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Newspaper Clipping - Newspaper Clipping Scan - Ancient wood found in Eagan - 12/27/2001F er 2,0 30 40 50 b¢' TO 8'0 Q`0 1.01) 110- rL9 (36 rsa 160 170 Cr, Ft(L7 DRAFT SA(VC) to 4-40 ato jag 3td irRc4.D PAN 3z 341° 3SD gybe) SRNi� t GR►�'J L Ij 1-4-ART) PAN srneti , unroc pr).. iW 1 12S-Z t S 5�4�® gj® L(3K.E &6i-r »n STkor •, wcsn� St-teU.S CALIK4S CIF SetAKOete tAggse um-06 p' e c i rtf�CtD sHR e.OP6C juCLtj:i Na J ` --- ; ( G✓v . S v Jw aw ((AL wt1cow\S(3\a^- q(cCLC' COrr-' lc Li:vt� c't°NJ�: $urw/ CCA 5 c. P fl P ,,,_ (\w(k uxxl - Sciu ✓ G� c'e cf t..A. u (cL€ � co IA) at- 4epro, (G L (OX- ) s1 + eac` tw) ekoA" �, ( Ult4l I = rock, (tAiff„k ce. ° 1 u t tYe.M �lU �.,F 1 a r • �' ' A/' OV W y37 eA., (1 1 a. ) 's[x14>. Show. ��+►r.ttL Si L v (KiI 2- Z7-0( Ancient wood found in Eagan JOEL JURGENS, UNIVERSITY OF MINNESOTA A magnified image of the wood shows decay caused by microorganisms. Unearthed spruce bits hold clues about past BY MARA H. GOTTFRIED Pioneer Press Three hundred feet beneath Eagan, well diggers have discovered evidence of an ancient spruce forest that could be from a time when wool- ly mammoths roamed Minnesota. University of Minnesota scientists are now trying to piece together the mystery of how old the tiny chunks of wood are and what they reveal about how the region once looked. "The people who live in that part of Dakota County probably don't know they have a little piece of histo- ry right below their feet," said Carrie Patterson, a geologist at the Universi- ANCIENT WOOD, 11A Ancient wood (continued) ty of Minnesota's Minnesota Geological Survey. The wood, which is believed to be 50,000 to 2 million years old, can help scientists under- stand the history of an ancient local river valley, which could lead to new understanding about climate changes. "It helps us reconstruct the history of events," Patterson said. "This wood is just a little piece in a huge jigsaw puzzle." The pieces started falling into place Nov. 27 as well drillers dug where the city is building Central Park, northwest of Yan- kee Doodle and Pilot Knob roads. A worker pulled up small chunks of wood at 198 feet and found bigger ones as he dug down to about 300 feet over the next week. Patterson recently began try- ing to narrow down the age of the wood. By examining sand and rocks that were brought up with it, she concluded that two glaciers probably covered the area at different times. In the place where the wood was found, a river valley once extended for miles through Dakota, Hennepin, Scott and Goodhue counties. Scientists don't know how old the river valley is. Trees in the area that is now Eagan were probably on the shore of the river. That river turned into a lake, and the trees somehow wound up in the lake, though Patterson isn't certain if they fell in or were shoved in by a passing glacier. What preserved the trees for all this time were the glaciers that passed over the lake. The most recent was probably the Superior Lobe, which came from the Lake Superior basin into what is now the Twin Cities area 18,000 to 50,000 years ago. The other glacier probably came through the area about 150,000 years ago, Patterson said, but that still doesn't nar- row down how old the wood could be: No one knows how long the trees were there before the glaciers passed by. The work of examining the wood fell to Robert Blanchette, a professor in the Plant Patholo- gy Department at the Universi- ty of Minnesota who specializes in wood microbiology. It didn't take Blanchette long The wood is believed to be 50,000 to 2 million years old. to figure out the pieces were spruce. Working with research scientists Joel Jurgens and Ben- jamin Held, the scientists froze a portion of the wood and cut it very thin so it could be exam- ined under a scanning electron microscope. They determined the tree grew in tundralike conditions. When counting the rings on the tree, Blanchette noted that the climate was so cold and harsh that the tree grew only 3/8 of an inch in 30 years because it had only a few weeks a year to grow. Under the microscope, the wood's cell walls looked like Swiss cheese, Blanchette said. The wood was heavily decayed by microorganisms that attacked it while it lay in a body of water. As research continues, Eagan's forestry supervisor, Gregg Hove, said he's thinking about sending the wood for car- 11M GEHRZ, PIONEER PRESS University of Minnesota geologist Carrie Patterson examines sand taken from the site of an ancient forest as she works in her second -floor office at the Minnesota Geological Survey in St. Paul. Patterson is trying to determine which of two glaciers deposited the sand in what is now Eagan. bon dating. But that might not yield more answers about the wood's age, because the tech- nique works only for objects that are 50,000 years old or less. Once Eagan completes con- struction on its community cen- ter, Hove said, he hopes to set up a display there with the wood and its history. "This wood is a wonderful find, and it was purely coinci- dental, because if we had drilled five feet over, we may have never found it," Hove said. "When you think about what this wood may tell us about Eagan and the area long ago, it's just amazing." Mara H. Gottfried can be reached at mgottfried@pioneerpress.com or (651) 228-5262. Ancient timber Well diggers in Eagan recently found spruce wood while digging about 300 feet underground. The wood is 50,000 to 2 million years old and from an ancient river valley in the region, scientists report. In the area that's now Eagan, the river formed a lake and the trees likely fell in or were pushed in by a passing glacier. ® Ancient river valleys Modern rivers Source: Minnesota Geological Survey ALEX LEARY, PIONEER PRESS t Signs of ancient forest surface in Eagan Well -diggers unearthed small chunks of wood believed to be 50,000 to 2 million years old. Associated Press Well diggers in Eagan have discovered tiny chunks of wood 300 feet underground that sci- entists believe is evidence of an ancient spruce forest from a time when woolly mammoths roamed Minnesota. The wood is believed to be 50,000 to 2 million years old. University of Minnesota scien- tists are working to get a closer estimate of its age. "The people who live in that part of Dakota County probably don't know they have a little piece of history right below their feet," said Carrie Patterson, a ge- ologist at the university's Min- nesota Geological Survey. The wood was found Nov. 27 by well drillers at a munici- pal building site. A worker pulled up small chunks of wood at 198 feet and found bigger ones as he dug down to about 300 feet over the next week. Patterson examined sand and rocks that were brought up with the wood and concluded that two glaciers probably cov- ered the area at different times. In the place where the wood was found, a river valley once extended for miles through Da- kota, Hennepin, Scott and Goodhue counties. Scientists don't know how old it is. Trees in the area that is now Eagan were probably on the shore of the river. It turned into a lake, and the trees somehow wound up in the lake, although Patterson isn't certain whether they fell in or were shoved in by a passing glacier. The glaciers helped pre- serve the wood. The most re- cent glacier was probably the Superior Lobe, which came from the Lake Superior basin into the Twin Cities area 18,000 to 50,000 years ago. The earlier glacier came through the area about 150,000 years ago. But that information alone doesn't pinpoint the age of the wood. Robert Blanchette, a profes- sor in the university's Plant Pa- thology Department who spe- cializes in wood microbiology, determined that the wood was spruce, using an electron mi- croscope. He determined that the tree grew in tundralike conditions. Blanchette said the climate was so cold and harsh that the tree could grow only three - eighths of an inch in 30 years. Ancient wood found at new Central Park gives clues to Eagan's past by Erin Johnson Staff Writer While drilling hundreds of feet into the ground of Eagan's new Central Park, workers dis- covered something unusual: pieces of wood where wood isn't normally found. At about 200 feet below the surface, small pieces of wood showed up; a large chunk was found about 300 feet down. Sandwiched among layers of sand, clay and gravel, the dis- covery caught the attention of workers, who rarely find organ- ic material that deep in the ground. They collected the sam- pies and contacted the city with their find. The wood ended up in the hands of Gregg Hove, Eagan's supervisor of forestry. Hove ini- tially thought to have the age of the pieces identified through carbon dating, but was told that carbon dating is only effective on materials less than 50,000 years old. Hove next contacted Dr. Bob Blanchette, a plant pathologist at the University of Minnesota and Hove's former college advisor. "He thought it was pretty cool," Hove said. Blanchette identified the wood as spruce. He told Hove the wood existed in a frigid cli- mate that had a growing season of only a few weeks per year. It took 30 years for the tree to grow only 3/8 of an inch. It would take only one or two years for a tree to grow that much today, Hove said. Blanchette passed samples on to Dr. Carrie Jennings Patterson, a senior scientist at the Minnesota Geological Survey, which is part of the University of Minnesota. The wood is indeed a find, she said. "It is not common to have vegetation like this preserved," she said. See Wood, 20A two separate glaciers. Examinations of the wood led Patterson to believe the area was once a large river valley that was buried by a glacier. The valley eventually drained and a new valley was formed on top of the old one. The decaying of the wood is thought to be caused by water. When the tree died, it had been submerged in water until a gla- cier came and stopped the degradation, preserving the wood. Whether the wood was car- ried in with a flood and strand- ed in the area or had fallen in from nearby is unknown, Patterson said. Patterson tried to interpret the setting in which the wood existed to determine its age. She said she believes it probably dates back near the end of the last interglacial period, 75,000 to 130,000 years ago. "But it could be older," she said. What has amazed Patterson most about the wood, however, has been the interest it has gen- erated. She has been inter- viewed by several area newspa- pers, appeared on KARE-11's "Simply Science" and spoke on a Cities 97 radio show. Pieces of wood found at Eagan's Central Park date back thousands of years. The largest piece of wood is six inches long and two to three inches across. Submitted photo "What's been most surpris- ing is how many people are blown away by this idea," she said, adding that maybe geolo- gists need to make their find- ings more public in the future. Patterson said the wood is a small clue in the larger picture of what the area was like many thousands of years ago. "It's a piece in a jigsaw puz- zle and that's what we spend our careers doing. We don't expect to figure it all out. We just expect to add our few pieces," she said. The wood has been returned to the city, which is looking into setting up an interpretive dis- play at the new Community Center with the Eagan Historical Society. The display will require special care so the wood isn't exposed to oxygen. Hove plans to discuss ideas with a company that specializes in geologic displays. ca.t q✓(.Jj 12- Z7-0( Anelent wood found in Eagan JOEL JURGENS, UNIVERSITY OF MINNESOTA A magnified image of the wood shows decay caused by microorganisms. Unearthed spruce bits hold clues about past BY MARA H. GOTTFRIED Pioneer Press Three hundred feet beneath Eagan, well diggers have discovered evidence of an ancient spruce forest that could be from a time when wool- ly mammoths roamed Minnesota. University of Minnesota scientists are now trying to piece together the mystery of how old the tiny chunks of wood are and what they reveal about how the region once looked. "The people who live in that part of Dakota County probably don't know they have a little piece of histo- ry right below their feet," said Carrie Patterson, a geologist at the Universi- ANCIENT WOOD, 11A Ancient wood (continued) ty of Minnesota's Minnesota Geological Survey. The wood, which is believed to be 50,000 to 2 million years old, can help scientists under- stand the history of an ancient local river valley, which could lead to new understanding about climate changes. "It helps us reconstruct the history of events," Patterson said. "This wood is just a little piece in a huge jigsaw puzzle." The pieces started falling into place Nov. 27 as well drillers dug where the city is building Central Park, northwest of Yan- kee Doodle and Pilot Knob roads. A worker pulled up small chunks of wood at 198 feet and found bigger ones as he dug down to about 300 feet over the next week. Patterson recently began try- ing to narrow down the age of the wood. By examining sand and rocks that were brought up with it, she concluded that two glaciers probably covered the area at different times. In the place where the wood was found, a river valley once extended for miles through Dakota, Hennepin, Scott and Goodhue counties. Scientists don't know how old the river valley is. Trees in the area that is now Eagan were probably on the shore of the river. That river turned into a lake, and the trees somehow wound up in the lake, though Patterson isn't certain if they fell in or were shoved in by a passing glacier. What preserved the trees for all this time were the glaciers that passed over the lake. The most recent was probably the Superior Lobe, which came from the Lake Superior basin into what is now the Twin Cities area 18,000 to 50,000 years ago. The other glacier probably came through the area about 150,000 years ago, Patterson said, but that still doesn't nar- row down how old the wood could be: No one knows how long the trees were there before the glaciers passed by. The work of examining the wood fell to Robert Blanchette, a professor in the Plant Patholo- gy Department at the Universi- ty of Minnesota who specializes in wood microbiology. It didn't take Blanchette long The wood is believed to be 50,000 to 2 million years old. to figure out the pieces were spruce. Working with research scientists Joel Jurgens and Ben- jamin Held, the scientists froze a portion of the wood and cut it very thin so it could be exam- ined under a scanning electron microscope. They determined the tree grew in tundralike conditions. When counting the rings on the tree, Blanchette noted that the climate was so cold and harsh that the tree grew only 3/8 of an inch in 30 years because it had only a few weeks a year to grow. Under the microscope, the wood's cell walls looked like Swiss cheese, Blanchette said. The wood was heavily decayed by microorganisms that attacked it while it lay in a body of water. As research continues, Eagan's forestry supervisor, Gregg Hove, said he's thinking about sending the wood for car- JIM GEHRZ, PIONEER PRESS University of Minnesota geologist Carrie Patterson examines sand taken from the site of an ancient forest as she works in her second -floor office at the Minnesota Geological Survey in St. Paul. Patterson is trying to determine which of two glaciers deposited the sand in what is now Eagan. bon dating. But that might not yield more answers about the wood's age, because the tech- nique works only for objects that are 50,000 years old or less. Once Eagan completes con- struction on its community cen- ter, Hove said, he hopes to set up a display there with the wood and its history. "This wood is a wonderful find, and it was purely coinci- dental, because if we had drilled five feet over, we may have never found it," Hove said. "When you think about what this wood may tell us about Eagan and the area long ago, it's just amazing." Mara H. Gottfried can be reached at mgottfried@pioneerpress.com or (651) 228-5262. Ancient timber Well diggers in Eagan recently found spruce wood while digging about 300 feet underground. The wood is 50,000 to 2 million years old and from an ancient river valley in the region, scientists report. In the area that's now Eagan, the river formed a lake and the trees likely fell in or were pushed in by a passing glacier. MN Ancient river valleys 0 Modern rivers Source: Minnesota Geological Survey ALEX LEARY, PIONEER PRESS Signs of ancient forest surface in Eagan Well -diggers unearthed small chunks of wood believed to be 50,000 to 2 million years old. Associated Press Well diggers in Eagan have discovered tiny chunks of wood 300 feet underground that sci- entists believe is evidence of an ancient spruce forest from a time when woolly mammoths roamed Minnesota. The wood is believed to be 50,000 to 2 million years old. University of Minnesota scien- tists are working to get a closer estimate of its age. "The people who live in that part of Dakota County probably don't know they have a little piece of history right below their feet," said Carrie Patterson, a ge- ologist at the university's Min- nesota Geological Survey. The wood was found Nov. 27 by well drillers at a munici- pal building site. A worker pulled up small chunks of wood at 198 feet and found bigger ones as he dug down to about 300 feet over the next week. Patterson examined sand and rocks that were brought up with the wood and concluded that two glaciers probably cov- ered the area at different times. In the place where the wood was found, a river valley once extended for miles through Da- kota, Hennepin, Scott and Goodhue counties. Scientists don't know how old it is. Trees in the area that is now Eagan were probably on the shore of the river. It turned into a lake, and the trees somehow wound up in the lake, although Patterson isn't certain whether they fell in or were shoved in by a passing glacier. The glaciers helped pre- serve the wood. The most re- cent glacier was probably the Superior Lobe, which came from the Lake Superior basin into the Twin Cities area 18,000 to 50,000 years ago. The earlier glacier came through the area about 150,000 years ago. But that information alone doesn't pinpoint the age of the wood. Robert Blanchette, a profes- sor in the university's Plant Pa- thology Department who spe- cializes in wood microbiology, determined that the wood was spruce, using an electron mi- croscope. He determined that the tree grew in tundralike conditions. Blanchette said the climate was so cold and harsh that the tree could grow only three - eighths of an inch in 30 years. Ancient wood found at new Central Park gives clues to Eagan's past by Erin Johnson Staff Writer While drilling hundreds of feet into the ground of Eagan's new Central Park, workers dis- covered something unusual: pieces of wood where wood isn't normally found. At about 200 feet below the surface, small pieces of wood showed up; a large chunk was found about 300 feet down. Sandwiched among layers of sand, clay and gravel, the dis- covery caught the attention of workers, who rarely find organ- ic material that deep in the ground. They collected the sam- pies and contacted the city with their find. The wood ended up in the hands of Gregg Hove, Eagan's supervisor of forestry. Hove ini- tially thought to have the age of the pieces identified through carbon dating, but was told that carbon dating is only effective on materials less than 50,000 years old. Hove next contacted Dr. Bob Blanchette, a plant pathologist at the University of Minnesota and Hove's former college advisor. "He thought it was pretty cool," Hove said. Blanchette identified the wood as spruce. He told Hove the wood existed in a frigid cli- mate that had a growing season of only a few weeks per year. It took 30 years for the tree to grow only 3/8 of an inch. It would take only one or two years for a tree to grow that much today, Hove said. Blanchette passed samples on to Dr. Carrie Jennings Patterson, a senior scientist at the Minnesota Geological Survey, which is part of the University of Minnesota. The wood is indeed a find, she said. "It is not common to have vegetation like this preserved," she said. See Wood, 20A two separate glaciers. Examinations of the wood led Patterson to believe the area was once a large river valley that was buried by a glacier. The valley eventually drained and a new valley was formed on top of the old one. The decaying of the wood is thought to be caused by water. When the tree died, it had been submerged in water until a gla- cier came and stopped the degradation, preserving the wood. Whether the wood was car- ried in with a flood and strand- ed in the area or had fallen in from nearby is unknown, Patterson said. Patterson tried to interpret the setting in which the wood existed to determine its age. She said she believes it probably dates back near the end of the last interglacial period, 75,000 to 130,000 years ago. "But it could be older," she said. What has amazed Patterson most about the wood, however, has been the interest it has gen- erated. She has been inter- viewed by several area newspa- pers, appeared on KARE-11's "Simply Science" and spoke on a Cities 97 radio show. Pieces of wood found at Eagan's Central Park date back thousands of years. The largest piece of wood is six inches long and two to three inches across. Submitted photo "What's been most surpris- ing is how many people are blown away by this idea," she said, adding that maybe geolo- gists need to make their find- ings more public in the future. Patterson said the wood is a small clue in the larger picture of what the area was like many thousands of years ago. "It's a piece in a jigsaw puz- zle and that's what we spend our careers doing. We don't expect to figure it all out. We just expect to add our few pieces," she said. The wood has been returned to the city, which is looking into setting up an interpretive dis- play at the new Community Center with the Eagan Historical Society. The display will require special care so the wood isn't exposed to oxygen. Hove plans to discuss ideas with a company that specializes in geologic displays. city of eagan TO: EAGAN HISTORICAL SOCIETY FROM: GREGG HOVE, SUPEVISOR OF FORESTRY DATE: FEBRUARY 4, 2002 SUBJECT: ANCIENT WOOD FROM EAGAN — CENTRAL PARK WELL TIMELINE SUMMARY November 27, 2001 — Mike Chell, Eagan Utility Supervisor, brings small wood pieces into my office. Unique because the well digger has never seen organic material being brought up from this depth (198 feet). November 29, 2001 — Mike Chell brings another larger piece of wood into my office (this piece came from a depth of 300 feet). Early December — a) Research into a consultant to carbon date these wood pieces. Beta Analytic, Miami, FL. This process only works for samples less than 50,000 years. Cost about $300.00. Time frame is about 30-45 days. b) Telephone call to Dr. Robert Blanchette, U of M Plant Pathology. Purpose to identify species of wood samples. Refer to his memo. All samples were spruce trees. "Three weeks growing season". Mid December - Referred to Dr. Carrie Patterson, Senior Scientist, Minnesota Geological Survey. Purpose to examine wood samples and records to place an approximate date on them, (see her memo). DISCUSSION = SEE PHOTOS, MEMOS, AND NEWSPAPER ARTICLES. Aerial view of site, photo of wood samples, scanning electron microscope (first shows wood species, second show internal degradation), Dr. Blanchette memo, Dr. Patterson memo, soil/well profile, St. Paul Pioneer Press article, Star Tribune article, Thisweek article. FUTURE PLANS Wood Sample Storage Educational Display, Possible Site = New Community Center (?) School Presentations t:\ghove\2002fi1e\misc\Eagan hist soc ancient wood memo January 11, 2002 Mr. Greg Hove City of Eagan 3501 Coachman Point Eagan, Minnesota 55122 Dear Greg, Thank you for the opportunity to look at the wood you found and for putting me in touch with Bob Blanchette. As you know, articles have appeared in the Pioneer Press, Minneapolis Star Tribune and Duluth paper. I was taped for "Simply Science" on KARE 11 (I am not sure when this will air if it has not already) and will be interviewed on this topic on Wed. Jan. 16 at 8:20 AM on the Cities 97. Today I was also in touch with Jessica Mandole of the Science Museum. She has probably already contacted you about a small display there. There was much more interest in this topic than I imagined. First I will outline the information I was able to glean from the drillers' daily logs and from looking at the sand that you sent me. Of course, it is always best to see the material first-hand but these are my interpretations based on the information given me. After I describe the log and my interpretations, I will place this information in a larger context. 0 - 40 Drift/Sand, brown. Interpretation: Sandy, reddish brown till of the Superior lobe. Late Wisconsinan glaciation. 40-77 Sand, brown. Interpretation: Stream sediment of the Superior lobe. 77-82 Sand and gravel. Interpretation: Coarser (nearer the glacier or higher energy) stream sediment of the Superior lobe. 82-95 Hardpan, brown. Interpretation: Another reddish brown, sandy till of the Superior lobe. We know that the Superior lobe was in this position at least twice during the Late Wisconsinan glaciation. 95-97 Sand: Interpretation: Stream sediment. 97-145 Hardpan, sand /trace of clay, brown. Interpretation: Till of the Superior lobe. This is not an unusual thickness of till given the location in a . moraine. 145-160 Sand and gravel, layered; brown. Interpretation: Stream sediment of the Superior lobe. 160-189 Sand, gray, sand and gravel, brown. Interpretation: Unoxidized stream sediment and oxidized stream sediment of the Superior lobe. Alternatively, we may be in the stream sediment of a glacier with a different source for its debris and the gray color is reflecting that change in source area. 189-198 Hardpan, gray, trace sand and gravel. Interpretation: Older, gray till with a northwest source. We unimaginatively call this till the "old gray till". Then the drillers changed bits and bailed the hole. The also drove casing to 190.34' before continuing drilling (as I read the log). 198-213 Sand (gray)/wood. Interpretation: Stream or beach sand with wood. The wood that I received actually had sand grain imbedded in it and as Dr. Blanchette noted, was rounded indicating it had been transported. 213-235 Sand (gray)/wood/decomposed grass reeds. Interpretation: deposits of a floodplain or shallow lake. 235-250 As above 250-260 As above, "lake bottom stuff". Interpretation. Deposits of a deeper lake or pond. This could be a cutoff meander lake or "oxbow" given its location in a buried bedrock valley or a "side lake" similar to the modern lakes on the Minnesota River floodplain that form behind the levees. 260-265 Sand, gray. Interpretation: stream sediment. 265-272 Sand, gravel, clay chunks, wood,shells. Interpretation: deposits of a lake or backwater on a flood plain. Clayey sediment is either in place or ripped up and redeposited by the stream that deposited the sand and gravel. 272-282 Sand, gravel, chunks of clay, shells, wood, rocks. Interpretation: as above. 282-290 Same stuff with chunks of Shakopee: Interpretation: Colluvium in stream sediment. This means that angular pieces of the local bluff - forming rocks fell into the stream and were not transported far before being buried by additional stream sediment. This indicates that the stream had moved to a position in its valley where it was impacting the channel wall. It could represent a flood event or rerouting of the stream. Given the nature of the sediment above this, the water flowing in this route was soon lessened to the point where the channel filled with finer sediment and became overgrown with reeds. The wood in this case would be drift wood in the stream. 290-295 Sand, light traces of gravel. Interpretation: stream sediment. 295-298 Gravel. Interpretation: coarser stream sediment 298-304 Sand, gravel, wood, chunks of Shakopee rock. Interpretation: stream sediment with colluvium (from rocky slopes) and either drift wood or wood that fell with the rock. 304-338 Sand, gravel, brown. Interpretation: stream sediment. 338-340 Shakopee (bedrock) The sample that I was given did not have a depth written on the bag. I am unsure where it came from exactly. However, there were no diagnostic grains in it that would indicate which glacier it was associated with. It is predominantly quartz. The quartz grains are angular to sub -rounded and clear, originating from a disaggregated granitic rock or saprolite to well-rounded and frosted, originating from the local sandstone bedrock. Quartz grains as well as the other types of sand grains found in this sample are resistant to physical weathering and survive vigorous and prolonged transport. Other grains included in the sample were local carbonate bedrock, iron -coated grains, feldspar and traces of dark, heavy minerals. The sand ranged from very fine to very coarse. I looked mainly at the 1-2mm sized sand grains for identification purposes. There may have been a couple of grains eroded from Cretaceous sands of the Ostrander formation. These grains have a characteristic polish. As you already know from the location of this drill hole with respect to the bedrock topography, the sand and gravel is associated with a buried valley carved into the bedrock. As far as we (I have discussed this with other survey geologists including Howard Hobbs and Gary Meyer) can tell, this bedrock stream was the master stream during the last interglacial and probably even prior to that. It is deeper and wider than the modern Mississippi but probably drained a similar area in central Minnesota. We interpret the greater depth and breadth to indicate that it existed for longer than the current, 10,000-15,000 year -old channel. According to the sequence of units in you hole, this valley was filling with sand and gravel that it was transporting. This could be just the normal bedload of the stream or it could represent the increase in sediment load due to an advancing glacier. I kind of favor the latter interpretation because of the cold climate indicated by the tree rings. In any case, the stream also hand chunks of the local bedrock falling into it at times. This probably means that it had somewhat steep bedrock walls. Then we see evidence for a lake forming near the river. This could either be an oxbow lake (cutoff meander) or a levee -dammed lake (side lake). It is still getting occasional deposits of sand and gravel so it close to the stream, but also has shells, reeds and grasses indicating that it is still and ponded some of the time. The wood is either carried in during flood events and gets stranded there or has fallen in from nearby. It is impossible to tell. We know from Dr. Blanchette's work that it was submerged in water as it decayed. Then a thin layer of gray till was apparently deposited over this stream sediment. It is possible that this till was also colluvial (meaning that it, too, fell from the valley walls to this position). The bulk of the material covering the channel fill is till and associated stream sediment from two advances of the Superior lobe. It is especially thick in this location because Eagan is located where the glacier stopped, depositing a thick end moraine. The wood is most likely from the end of the last interglacial and beginning of the Late Wisconsinan glaciation. It is definitely older than the St. Croix moraine, deposited approximately 20,000 years ago, most likely older than the first advance of the Superior lobe, not well dated but likely 30-40,000 years old, and probably dates to near the end of the last interglacial, 130,000 to 75,000 years before present. If you decide to have Beta Analytical get a radiocarbon date, have them do an extended count to push the date as far back as possible. It will most likely yield a "greater than the limit" date but even that could help to constrain our story. If there is anything else that you would like me to look at (gamma log, more drill cuttings) I would be happy to. I am including the business card of Kate Pound with Earthfolio. She is the person that I recommended help when you are ready to develop your interpretive display. Sincerely, Dr. Carrie Jennings Patterson Senior Scientist Minnesota Geological Survey to 30 '1V 50 60 TO 9'O (T0 toe tto ILO (36 rite tab ' C.1c.. F lt„(„_ l DRAFT S to N C) sPtNp rtPtRZ PQN S1.i2P4C6 Sur1.. « (Si Lit (�a{, UJtScw`Sta. - ettGcLv/ ( U U-•' S c v S e," t .Mo.,. L (L ;c- �U. T (( cA9-S`( ch"----) tTo SRNI� GRNet.. 5geel tw..t (-/tAw(0Lit ten o hvr.._ cr." SUtd✓G� 14AIM PAN 1 4��1 Zoo swvoD Zn LLo 0-6 4,44 LSo 44,0 ]06 t,t' E gbTTom STUFF " C5-01 St-teu CAutyKS of StrAg.orCE I,-tL(se tu1JD( Pi ; J 346 3$D 36b 3�0 33 0 3`1 .:1-42 17.S r-! t 6y S,t.c\i C1w l.cC-R /I Lcx c rto.' ------- ��Q� � t , d 5� (��,.. ,Get atl)I ?(o : 1 �iti-�G• -- ()ac`"w) (L4" .\L( 11441) = vac 5 �i it( on ( J co k0:4' t;.Y• t.ut a" W'rsY ia• << I t 24) FriS tt f j SmtU .rcchMtJY t-tf�RD SHRr;,oPeC jrock_ t joCLN S-CutvC- , J ` March 5, 2002 Ray Wade RE: Ancient wood from well drilling in Eagan, MN Dear Ray: The papers you gave me report that spruce wood was buried beneath ca. 300 feet of deposits, now lying under Eagan, MN. These deposits were most likely brought in by glaciation. The position of the wood indicates that the deposits were laid down over the wood, or that the wood was fixed in place (rooted?) before the glacial deposits covered it. The analysis of the wood indicates that it was most likely growing near the edge of the glacier (cold climate — slow growth). The glacier itself may have covered the wood first, then the deposits were laid down as the glacier ice melted away. The ice may not have actually covered the wood, but it may have been buried by outwash deposits as the glacier melted away. Evidence of microbial action in the wood may indicate that the wood was already ground up before the glacier buried it. I am not an expert in any of these things, so others would be better able to discuss the meaning of these findings. You asked, "Is this evolution?" The action of a glacier on woodland, and the deposition of soils are not themselves evolution, but they may have been factors that brought about biological (evolutionary) changes. If the spruce wood in the deposits is of a different (probably extinct) species than the present ones, then it could be said that evolution has occurred to.bring about new species from previous species under the influence of climate changes related to glaciation. Evolution is a very broad term defining the process of change. Long -tern climate changes, such as ice -ages in which glaciers cover previously unglaciated areas and cold climate could, in this general sense, be considered evolutionary change as far as the earth is concerned. But in terms of biological evolution, i.e., new species arising from previous species acted upon by environmental changes, the climate changes of the ice ages were the tools of evolution but not evolution itself. I heard about this in general, but now I have the benefit of the materials you gave me. Thank you. Joe Hopwood SuR.PrtCE ,o 30 ��cicf LL_l DR.t t SfnNC) 40 5d 66 TO QD lob (to 170 Set;vt HR.D PAN snNa , GR►O�EI. HARD PAN Zoo a SrnALU unroV Ito Z36 �,' 62r3sS t tZszOS 444 LS"p SEA N��®\® LAKE gb'TTowt StUC ' V �� - 44'0 eo l b jaa jtr, W CFO S t-f E- lrl- S CL UNKj of Set AK.°PC`E LAg-tse uatiob pieceS 316 35 3�0 31 0 3'► rtA[zD SHR K.OPEC c G�,r... suI ��w ( • L ((t%cw\SI'a- -. c v Sec((..".,��� T,((�,�.S�r�� �o 3 ct rL G Yrvb4. cr l l t ter ivro—s) ryz, S v/Lo w CciLQ l\w(k.t, ale' jtlu ✓ G� cip 7.s�1 t 6y S1r...«crw (6Le /11.0 r(c.r-,. �_ cLe fro 1; J �i� � yr ` c G-Q (OX y✓/ i UY Jtc� Nrn V r [!i (tad 1)(0 • y, 1+"*ncee-4t� (Lc,., Al.( 1.1 U I = roc. k s ►rt (t Qtovvvi r Jo(L17) SiONfi ' J - 1ejiy _ A1T,ient wood (continued) ty of Minnesota's Minnesota Geological Survey. The wood, which is believed to be 50,000 to 2 million years old, can help scientists under- stand the history of an ancient local river valley, which could lead to new understanding about climate changes. "It helps us reconstruct the history of events," Patterson said. "This wood is just a little piece in a huge jigsaw puzzle." The pieces started falling into place Nov. 27 as well drillers dug where the city is building Central Park, northwest of Yan- kee Doodle and Pilot Knob roads. A worker pulled up small chunks of wood at 198 feet and found bigger ones as he dug down to about 300 feet over the next week. Patterson recently began try- ing to narrow down the age of the wood. By examining sand and rocks that were brought up with it, she concluded that two glaciers probably covered the area at different times. In the place where the wood was found, a river valley once extended for miles through Dakota, Hennepin, Scott and Goodhue counties. Scientists don't know how old the river valley is. Trees in the area that is now Eagan were probably on the shore of the river. That river turned into a lake, and the trees somehow wound up in the lake, though Patterson isn't certain if they fell in or were shoved in by a passing glacier. What preserved the trees for all this time were the glaciers that passed over the lake. The probably the Superior Lobe, which came from the Lake Superior basin into what is now the Twin Cities area 18,000 to 50,000 years ago. The other glacier probably came through the area about 150,000 years ago, Patterson said, but that still doesn't nar- row down how old the wood could be: No one knows how long the trees were there before the glaciers passed by. The work of examining the wood fell to Robert Blanchette, a professor in the Plant Patholo- gy Department at the Universi- ty of Minnesota who specializes in wood microbiology. It didn't take Blanchette long The wood is believed to be 50,000 to 2 million years old. to figure out the pieces were spruce. Working with research scientists Joel Jurgens and Ben- jamin Held, the scientists froze a portion of the wood and cut it very thin so it could be exam- ined under a scanning electron microscope. They determined the tree grew in tundralike conditions. When counting the rings on the tree, Blanchette noted that the climate was so cold and harsh that the tree grew only 3/8 of an inch in 30 years because it had only a few weeks a year to grow. Under the microscope, the wood's cell walls looked like Swiss cheese, Blanchette said. The wood was heavily decayed by microorganisms that attacked it while it lay in a body of water. As research continues, Eagan's forestry supervisor, Gregg Hove, said he's thinking about sending the wood for car- JIM GEHRZ, PIONEER rneiS University of Minnesota geologist Carrie Patterson examines sand taken from the site of an ancient forest as she works in her second -floor office at the Minnesota Geological Survey in St. Paul. Patterson is trying to determine which of two glaciers deposited the sand in what is now Eagan. bon dating. But that might not yield more answers about the wood's age, because the tech- nique works only for objects that are 50,000 years old or less. Once Eagan completes con- struction on its community cen- ter, Hove said, he hopes to set up a display there with the wood and its history. "This wood is a wonderful find, and it was purely coinci- dental, because if we had drilled five feet over, we may have never found it," Hove said. "When you think about what this wood may tell us about Eagan and the area long ago, it's just amazing." Mara H. Gottfried can be reached at mgottfried@pioneerpress.com or (651) 228-5262. Ancient timber Well diggers in Eagan recently found spruce wood while digging about 300 feet underground. The wood is 50,000 to 2 million years old and from an ancient river valley in the region, scientists report. In the area that's now Eagan, the river formed a lake and the trees likely fell in or were pushed in by a passing glacier. ® Ancient river valleys O Modern rivers Source: Minnesota Geological Survey ALEX LEARY, PIONEER PRESS (c . l ( 2- Z7-o( kncient wood found in Eagan JOEL JURGENS, UNIVERSITY OF MINNESOTA A magnified image of the wood shows decay caused by microorganisms. Unearthed spruce bits hold clues about past BY MARA II. GOTTFRIED Pioneer Press Three hundred feet beneath Eagan, well diggers have discovered evidence of an ancient spruce forest that could be from a time when wool- ly mammoths roamed Minnesota. University of Minnesota scientists are now trying to piece together the mystery of how old the tiny chunks of wood are and what they reveal about how the region once looked. "The people who live in that part of Dakota County probably don't know they have a little piece of histo- ry right below their feet," said Carrie Patterson, a geologist at the Universi- ANCIENT WOOD, 11A J Signs of ancient forest surface in Eagan Well -diggers unearthed small chunks of wood believed to be 50,000 to 2 million years old. Associated Press Well diggers in Eagan have discovered tiny chunks of wood 300 feet underground that sci- entists believe is evidence of an ancient spruce forest from a time when woolly mammoths roamed Minnesota. The wood is believed to be 50,000 to 2 million years old. University of Minnesota scien- tists are working to get a closer estimate of its age. 'The people who live in that part of Dakota County probably don't know they have a little piece of history right below their feet," said Carrie Patterson, a ge- ologist at the university's Min- nesota Geological Survey. The wood was found Nov. 27 by well drillers at a munici- pal building site. A worker pulled up small chunks of wood at 198 feet and found bigger ones as he dug down to about 300 feet over the next week. Patterson examined sand and rocks that were brought up with the wood and concluded that two glaciers probably cov- ered the area at different times. In the place where the wood was found, a river valley once extended for miles through Da- kota, Hennepin, Scott and Goodhue counties. Scientists don't know how old it is. Trees in the area that is now Eagan were probably on the shore of the river. It turned into a lake, and the trees somehow wound up in the lake, although Patterson isn't certain whether they fell in or were shoved in by a passing glacier. The glaciers helped pre- serve the wood. The most re- cent glacier was probably the Superior Lobe, which came from the Lake Superior basin into the Twin Cities area 18,000 to 50,000 years ago. The earlier glacier came through the area about 150,000 years ago. But that information alone doesn't pinpoint the age of the wood. Robert Blanchette, a profes- sor in the university's Plant Pa- thology Department who spe- cializes in wood microbiology, determined that the wood was spruce, using an electron mi- croscope. He determined that the tree grew in tundralike conditions. Blanchette said the climate was so cold and harsh that the tree could grow only three - eighths of an inch in 30 years. Ancient wood found at new Central Park gives clues to Eagan's past by Erin Johnson Staff Writer While drilling hundreds of feet into the ground of Eagan's new Central Park, workers dis- covered something unusual: pieces of wood where wood isn't normally found. At about 200 feet below the surface, small pieces of wood showed up; a large chunk was found about 300 feet down. Sandwiched among layers of sand, clay and gravel, the dis- covery caught the attention of workers, who rarely find organ- ic material that deep in the ground. They collected the sam- pies and contacted the city with their find. The wood ended up in the hands of Gregg Hove, Eagan's supervisor of forestry. Hove ini- tially thought to have the age of the pieces identified through carbon dating, but was told that carbon dating is only effective on materials less than 50,000 years old. Hove next contacted Dr. Bob Blanchette, a plant pathologist at the University of Minnesota and Hove's former college advisor. "He thought it was pretty cool," Hove said. Blanchette identified the wood as spruce. He told Hove the wood existed in a frigid cli- mate that had a growing season of only a few weeks per year. It took 30 years for the tree to grow only 3/8 of an inch. It would take only one or two years for a tree to grow that much today, Hove said. Blanchette passed samples on to Dr. Carrie Jennings Patterson, a senior scientist at the Minnesota Geological Survey, which is part of the University of Minnesota. The wood is indeed a find, she said. "It is not common to have vegetation like this preserved," she said. See Wood, 20A two separate glaciers. Examinations of the wood led Patterson to believe the area was once a large river valley that was buried by a glacier. The N )•eventually drained and a new valley was formed on top of the old one. The decaying of the wood is thought to be caused by water. When the tree died, it had been submerged in water until a gla- cier came and stopped the degradation, preserving the wood. Whether the wood was car- ried in with a flood and strand- ed in the area or had fallen in from nearby is unknown, Patterson said. Patterson tried to interpret the setting in which the wood existed to determine its age. She said she believes it probably dates back near the end of the last interglacial period, 75,000 to 130,000 years ago. "But it could be older," she said. What has amazed Patterson r---t about the wood, however, aeen the interest it has gen- erated. She has been inter- viewed by several area newspa- pers, appeared on KARE-1 1's "Simply Science" and spoke on a Cities 97 radio show. Pieces of wood found at Eagan's Central Park date back thousands of years. The largest piece of wood is six inches long and two to three inches across. Submitted photo "What's been most surpris- ing is how many people are blown away by this idea," she said, adding that maybe geolo- gists need to make their find- ings more public in the future. Patterson said the wood is a small clue in the larger picture of what the area was like many thousands of years ago. "It's a piece in a jigsaw puz- zle and that's what we spend our careers doing. We don't expect to figure it all out. We just expect to add our few pieces," she said. The wood has been returned to the city, which is looking into setting up an interpretive dis- play at the new Community Center with the Eagan llistorical Society. The display will require special care so the wood isn't exposed to oxygen. Hove plans to discuss ideas with a company that specializes in geologic displays. city of eagan TO: EAGAN HISTORICAL SOCIETY FROM: GREGG HOVE, SUPEVISOR OF FORESTRY DATE: FEBRUARY 4, 2002 SUBJECT: ANCIENT WOOD FROM EAGAN — CENTRAL PARK WELL TIMELINE SUMMARY November 27, 2001 — Mike Chell, Eagan Utility Supervisor, brings small wood pieces into my office. Unique because the well digger has never seen organic material being brought up from this depth (198 feet). November 29, 2001 — Mike Chell brings another larger piece of wood into my office (this piece came from a depth of 300 feet). Early December — a) Research into a consultant to carbon date these wood pieces. Beta Analytic, Miami, FL. This process only works for samples less than 50,000 years. Cost about $300.00. Time frame is about 30-45 days. b) Telephone call to Dr. Robert Blanchette, U of M Plant Pathology. Purpose to identify species of wood samples. Refer to his memo. All samples were spruce trees. "Three weeks growing season". Mid December - Referred to Dr. Came Patterson, Senior Scientist, Minnesota Geological Survey. Purpose to examine wood samples and records to place an approximate date on them, (see her memo). DISCUSSION = SEE PHOTOS, MEMOS, AND NEWSPAPER ARTICLES. Aerial view of site, photo of wood samples, scanning electron microscope (first shows wood species, second show internal degradation), Dr. Blanchette memo, Dr. Patterson memo, soil/well profile, St. Paul Pioneer Press article, Star Tribune article, Thisweek article. FUTURE PLANS Wood Sample Storage Educational Display, Possible Site = New Community Center (?) School Presentations l:\ghove\2002fileUnisc\Eagan hist soc ancient wood memo J /I SMEAD• KEEPING YOU ORGANIZED No. 10334 2-1 53L SUSTAINAeU E Mk RECYCLED FORESTRY INITIATIVECQYiEM10% Certified Rb.r Sourcing POSTGONSUN6t www.tPyragr.mmy 1• f.: MADE IN USA GET ORGANIZED AT SMEAD.COAI FEBRUARY 16, 2002 A; atplacie 551-222-111 VRESTLING PNIGHT! 2 OFF MrWTH THIS A 1 coupon Per perms Feb. 1 • th, 7:30 PM Saint Paul Armory et in West St. Paul, MN doors open at 6:30 Available t The Door $15 - Adults 0 - Kids 12 K under SDW on Channel 45 k Local Listings tg Hotline 65f-306.2231 LOCAL NEWS WWW_TWI14CITIES.COM ■ ST. PAUL PIONEER PRESS SOUTH SUBURBS EAGAN Dig unearths clues to icy geologic past Wood, sediment links area to glaciers BY MARA It. GOTTFRIED Pioneer Press The ancient spruce un- earthed in Fagan in November also brought sand, rocks, silt and clay from deep under ground. That glacier and stream sediment now offers more chies to the wood's past. The sediment harkens to the time of glaciers and puts the wood's age at 75,000 to 1.50,000 years old. But it could be much alder and the exact age of the spruce may always remain a mystery, said a University of Minnesota scientist. Since the small pieces of wood were found, there has been much oonmiunity interest. "People don't pay much attention to the surface we're on, let alone what lies beneath," said Carrie Patterson, a geolo- gist at the University of I4In- nesota's Minnesota Geological Survey. "So this probably came as a surprise to many people. It realty is a tangible connection to the past." The wood, which was initial- ly believed to be 50,000 to 2 mil- lion years old, can help scien- tists understand the history of an ancient local river valley and lead to new undecstaruling about climate changes. On Nov 27, well drillers dug where the city is building Cen- tral Park, northwest of Yankee Doodle and Not Knob roads. A worker pulled up small drinks of wood at 198 feet and found bigger pieces as be dug down to about 300 feet over the next week. The quartz grains brought up with the wood didn't indicate what glacier they came from, Patterson said. But they did help tell the story of a river val- ley that once went through Dakota, Hennepin, Scott and Goodhue counties. IL was the main river inthe area during the last period between glaraers and perhaps RIVER FALLS HOME FURNISHINGS HUGE SAVINGS IN EVERY DEPARTMENT PLUS... before that, Patterson said. Compared with the modem Mi issippi River, the ancient river would have been deeper and wider, but drained in a simi- lar area in central Minnesota At sonic point, an advancing glacier likely tfled in the river A slide lake formed near the river in the area that's now Ragan and trees from a spruce forest either fell in or w+tre car- ried in during a flood, Patterson said Another University of Min nesota scientist examined the wood in December and deter- red then that the wood grew in tundra -like conditions. When counting the rings an thc tree, Robert Blanchette, a professor in the Plant Pathology Depart- ment, noted the climate was so cold and harsh that the tree grew It of an inch in 30 years because it had only a few weeks a year to grow. A layer of tall was deposited over the lalae by the advancing Superior Lobe and perhaps an earlier glacier In Eagan, the deposit was e'p©ially large because that's likely the area where the glacier stopped, Pat terson said The wood is probably from the end of the last period between glaciers and the begin- ning of the Late Wisconsin gla- cier Yet discovering the exact age of the wood is largely insnificarnt, said Eagan's forestry supervisor, Gregg TO LEARN MORE • The Science Museum of Minnesota in St_ Paul has three pictures of the wood under an electron microscope on display in an area on current sci- ence news. The small dis- play will be there for about a month. • Eagan and Burnsville residents can watch a segment about the wood on "Community Journal," a cable access program showing throughout Feb- ruary. The show is on daily at 6 a.m., noon and 6 p.m_ what's important is that we got a pretty nice picture of what happened to the wood and where it came from," he said. The six pieces of wood have been vacuum -sealed and are being stored in a cool, dark place to prevent decay, since they had been waterlogged and were fragile. One day they will be put in dear, acrylic blocks for a dis- play; which lave is in the pre- liminary stages of planning. The exhibit would likely be in the citys community center; which opens next year, but could be mowed to the library and schools. Mara 13_ Gottfried can be reached jkl,St,de,e_K 01- Iq - 2)3D2 Ancient wood found at new Central Park gives clues to Eagan's past by Erin Johnson Staff Writer While drilling hundreds of feet into the ground of Eagan's new Central Park, workers dis- covered something unusual: pieces of wood where wood isn't normally found. At about 200 feet below the surface, small pieces of wood showed up; a large chunk was found about 300 feet down. Sandwiched among layers of sand, clay arid gravel, the dis- covery caught the attention of workers, who rarely find organ- ic material that deep in the ground. They collected the sam- two separate glaciers. Examinations of the wood led Patterson to believe the area was 'once a large river valley that was buried by a glacier: The valley eventually drained and a new valley was formed on top of the old one. The decaying of the wood is thought to be caused by water. When the tree died, it had been submerged in water until a gla- cier came and stopped the degradation, preserving the wood. Whether the wood was car- ried in with a flood and strand- ed in the area .or had fallen in from nearby is unknown, Patterson said. Patterson tried to interpret the setting in which the wood existed to determine its age. She said she believes it probably dates back near the end of the last interglacial period, 75,000 to 130,000 years ago. "But it could be older," she said. What has amazed Patterson most about the wood, however, has been the interest it has gen- erated. She has been inter- viewed by several area•newspa- pers, appeared on KARE-11's "Simply Science" and spoke on a Cities 97 radio show. pies and contacted the city with their find. The wood ended up in the hands of Gregg Hove, Eagan's supervisor of forestry. Hove ini- tially thought to have the age of the pieces identified through carbon dating, but was told that carbon dating is only effective on materials less than 50,000 years old. Hove next contacted Dr. Bob Blanchette, a plant pathologist at the University of Minnesota and Hove's former college advisor. "He thought it was pretty cool," Hove said. Blanchette identified the wood as spruce. He told Hove the wood existed in a frigid cli- mate that had a growing season of only a few weeks per year. It took 30 years for the tree to grow only 3/8 of an inch. It would take only one or two years for a tree to grow that much today, Hove said. Blanchette passed samples on to Dr. Carrie Jennings Patterson, a senior scientist at the Minnesota Geological Survey, which is part of the University of Minnesota. The wood is indeed a find, she said. "It is not common to have vegetation like this preserved," she said. See Wood, 20A Wood/From 1 A :File area where the wood was found, she said, likely saw Pieces of wood found at Eagan's Central Park date back thousands of years. The largest piece of wood is six inches long and two to three inches across. Submitted photo "What's been most surpris- ing is how many people are blown away by this idea," she said, adding that maybe geolo- gists need to make their find- ings more public in the future. Patterson said the wood is a small clue in the larger picture of what the area was like many thousands of years ago. "It's a piece in a jigsaw puz- zle and that's what we -spend our careers doing. We don't expect to figure it all out. We just expect to add our few pieces," she said. The wood has been returned to the city, which is looking into setting up an interpretive dis- play at the new Community Center with the Eagan Historical Society. The display will require special care so the wood isn't exposed to oxygen. Hove plans to discuss ideas with a company that specializes in geologic displays. SAINT PAUL PIONEER PRESS SUNDAY. MAY ib. iS J9 SOUTH SUBURBAN NEIGHBORS SERVING APPLE VALLEY • EAGAN • INVER GROVE HEIGHTS • LAKEVILLE • ROSEMOUNT EAGAN: HIGHRIDGE TERRACE V Putting RooDown Area of detail 1 '494 PIONEER PRESS • JOE ODEN/P10NEER PRESS Maggie Jacobson describes the 40-year-old ash tree that was destroyed in her back yard in Eagan during May storms last year. AT A GLANCE • Best: Residents look out for each other. close to Min- nesota River and Fort Snelling State Park. • Worst: Airplane noise. • Location: High - ridge Terrace is in the Valley View Plateau neighbor- hood close to the Mendota Heights border. The neigh- borhood is south of Lost Spur Country Club, west of Pilot Knob Road, north of Lone Oak Road, east of Highway 13. • Homes: Single- family mostly built in the 1950s. • Schools: Pilot Knob Elementary, Friendly Hills Middle School, Sibley High School. FYI "Eagan ... Forev- er Green!" will distribute another batch of plants in the fall. For infor- mation, call the city at (651) 681- 4600. • • y now, nearly all Eagan resi- dents who had to fix up their homes after last May's vicious rainstorm have finished home repairs, but one "repair" will take years: replacing large trees. But a city program, "Eagan ... For- ever Green!" is giving residents a head start by selling low-cost trees. On May 6 and 8, about 2,300 trees were distributed to neighbors throughout the city. Highridge Terrace is one of many neighborhoods in the city that have taken advantage of the program. Folks have planted oaks, maples and other varieties of trees. Three skinny trees now stand in Mag- gie.Jacobson's front yard, replacing the decades -old pine trees that fell like dominoes. "There is not a day that I look out the front window and don't miss those trees," Jacobson said. She also lost a 40- year-0Id ash tree in the back yard that fell into her pool. All that's left of it now is a patch of dirt and a pile of Togs. The, storm damaged homes and busi- nesses throughout the metro area. Clear- ly, repairing homes was the top priority, but residents who had come to love their People in Highridge Terrace still miss the trees that once stood majestically over their homes and yards. But the destructive storm last May did cement relationships in an already close neighborhood. towering trees speak emotionally about the loss. "(Trees) add character, warmth, homeyness," said Jacob- son, a self -described plant freak who has plants all over her house. Jacobson thinks the street looks more like a new subdivision since many of the large trees are gone. But there is a silver, or in this case, a green lining to the loss. The storm brought together an already close neigh- borhood. Highridge has always been the sort of place where neighbors keep a watchful eye on each other's homes when someone is on vacation, gather for Christmas parties and hold potlucks in the summer while the kids play kickball in the street. That close-knit atmosphere helped res- idents weather the storm. The night the BY AMY SHERMAN STAFF WRITER storm hit, a couple of neighbors knocked on doors to make sure everyone was OK. When most residents lost electricity, neigh- bors stored food in the freezer of one who had electricity, said Jenene Fredell, a Highridge resi- dent. Fredell still pines for the 25-year-old beautiful red sugar maple in her front yard. The tree used to cover up so much of the house that people who have driv- en by say they don't even recognize her home. The Fredells Jost nine trees but have planted some new ones. In an effort to help such neighbor- hoods, the city of Eagan teamed up with several companies and organizations to start a tree replacement program last year. In May, the group held the second of three rounds of sales. In all, the pro- gram will bring 10,000 new trees to the city — 5,000 trees measuring up to 10 feet tall and 5,000 seedlings. It will take years for the trees to grow to the height they once were, but it's a start. Jacobson talked up the pro- gram on her street, delivering forms to her neighbors. At age 67, Les Swenson said he won't live to feel the shade of his new trees. He replanted quickly, before the tree program began. "(The storm) bared out the place. It was hard to visualize the emptiness 'cause it was so full. May 31, it was just getting all greened up good, now it's all gone." But Swenson still appreciates the trees that remain. "It's a beautiful -looking neighborhood," said Swenson, describing the flowering crabapple trees in bloom and the lilac trees. "It's a beautiful area. It was more beautiful before the trees got chopped up. Amy Sherman, who covers Eagan, Inver Grove Heights and Rosemount. can be reached at asherman@pioneerpress.com or (651) 228- 2174. 01/07/2002 11:05 EAGAN MAINT FAC 4 CITY HALL NO.200 P01 7671 oate',7 O�pe9Bs* Post -it' Fax Note From GR-Efi4 1 OtR Ta Itiel K) 2?'1 Co./Dept. c Phone 1 Plane k Fax N Fax q Sl .T>Q I Z- Z-7-0( Acieut wood found in Eagan MELJURGENS, WiNERSTY OF MINNESOTA A magnified Image of the wood shows decay caused by microorganisms. Unearthed spruce bits hold clues about past SI MARA H. GOTTFRIED Pioneer Press Three hundred feet beneath Eagan, well diggers have discovered evidence of an ancient spruce forest that could be from a time when wool- ly mammoths roamed Minnesota. University of Minnesota scientists are now trying to piece together the mystery of how old the tiny chunks of wood are and what they reveal about how the region once looked "The people who live in that part of Dakota County probably don't know they have a little piece of histo- ry right below their feet," said Carrie Patterson, a geologist at the Universi- ANCIENT WOOD, 11A Ancient wood (continued) ty of Minnesota's Minnesota Geological Survey. The wood, which Is believed to be 50,000 to 2 million years old, can help scientists under- stand the history of an ancient local river valley, which could lead to new understanding about climate changes. "It helps us reconstruct the history of events," Patterson said. "This wood is just a little piece in a huge jigsaw puzzle." The pieces started flitting into place Nov. 27 as well drillers dug where the city is building Central Park, northwest of Yan- kee Doodle and Pilot Knob roads. A worker pulled up small chunks of wood at 198 feet and found bigger ones as he dug down to about 300 feet over the next week. Patterson recently began try- , ing to narrow down the age of the wood. By examining sand and rocks that were brought up with it., she concluded that two glaciers probably • covered the area at different times. In the place where the wood was found, a aver valley once extended for miles through Dakota, Hennepin, Scott and Goodhue counties. Scientists don't know how old the river valley is. 'frees in the area that is now Eagan were probably on the shore of the river. That river turned into a lake, and the trees somehow wound up in the lake, though Patterson isn't certain if they fell in or were shoved in by a passing glacier. What preserved the trees for all this time were the glaciers that passed over the lake. The most recent was probably the Superior Lobe, which came from the Lake Superior basin into what is now the Twin Cities area 18,000 to 50,006 years ago. The other glacier probably came through the area about 150,000 years ago, Patterson said, but that still doesn't nar- row down how old the wood could be: No one knows how Iong the trees were there before the glaciers passed by. The work of examining the wood fell to Robert Blanchette, a professor in the Plant Patholo- gy Department. at the Universi- ty of Minnesota who specializes in wood microbiology. It didn't take Blanchette long The wood is believed to be 50,000 to 2 million years old. to figure out the pieces were spruce. Working with research scientists Joel Jurgens and Ben- jamin Held, the scientists froze a portion of the wood and cut it very thin so it could be exam- ined under a scanning electron microscope. They determined the tree grew in tundralike conditions. When counting the rings on the tree, Blanchette noted that the climate was so cold and harsh that the tree grew only 3/8 of an inch in 30 years because It had only a few weeks a year to grow. Under the microscope, the wood's cell walls looked like Swiss cheese, Blanchette said. The wood was heavily decayed by microorganisms that attacked it while It lay in a body of water. As research continues, Eagan's forestry supervisor, Gregg Hove, said he's thirzlcing about sending the wood for car- JIM (, HR2, PIONEER PRESS University of Minnesota geologist Carrie Patterson examines sand taken from the site of an ancient forest as she works in her second -floor office at the Minnesota Geological Survey in St. Paul. Patterson is trying to determine which of two glaciers deposited the sand in what is now Eagan. bon dating. But that might not yield more answers about the wood's age, because the tech- nique works only for objects that are 50,000 years old or less. Once Eagan completes con- struction on Its community cen- ter, Hove said, he hopes to set up a display • there with the wood and its history "This wood is a wonderful find, and it was perely coinci- dental, because 1f we had drilled five feet. over, we may have never found it," Hove said. "When you think about what this wood may tell us about Eagan and the area long ago, It's just amazing." Mara 11. Gottfried can be reached at mgattfriedCapiofeerpress.cor++ or (651) 228-5262. Ancient timber Well diggers in Eagan recently found spruce wood while digging about 300 feet underground. The wood is 50,000 to 2 million years old and from an ancient river valley in the region, scientists report. In - the area that's now Eagan, the river formed a lake and the trees likely fell in or were pushed in by a passing glacier. IMO Ancient river valleys p Modem rivers Source: Minnesota G-oloalcel Survey ALEX UEARY, PIONEER PREYS 200E/L0iti0 11dH k±I3 F add 1NIdW Nd9d3 Vika® UPC 10330 No. 153L HASTINGS, MN city of eagan TO: EAGAN HISTORICAL SOCIETY FROM: GREGG HOVE, SUPEVISOR OF FORESTRY DATE: FEBRUARY 4, 2002 SUBJECT: ANCIENT WOOD FROM EAGAN — CENTRAL PARK WELL TIMELINE SUMMARY November 27, 2001 — Mike Chell, Eagan Utility Supervisor, brings small wood pieces into my office. Unique because the well digger has never seen organic material being brought up from this depth (198 feet). November 29, 2001 — Mike Chell brings another larger piece of wood into my office (this piece came from a depth of 300 feet). Early December — a) Research into a consultant to carbon date these wood pieces. Beta Analytic, Miami, FL. This process only works for samples less than 50,000 years. Cost about $300.00. Time frame is about 30-45 days. b) Telephone call to Dr. Robert Blanchette, U of M Plant Pathology. Purpose to identify species of wood samples. Refer to his memo. All samples were spruce trees. "Three weeks growing season". Mid December - Referred to Dr. Carrie Patterson, Senior Scientist, Minnesota Geological Survey. Purpose to examine wood samples and records to place an approximate date on them, (see her memo). DISCUSSION = SEE PHOTOS, MEMOS, AND NEWSPAPER ARTICLES. Aerial view of site, photo of wood samples, scanning electron microscope (first shows wood species, second show internal degradation), Dr. Blanchette memo, Dr. Patterson memo, soil/well profile, St. Paul Pioneer Press article, Star Tribune article, Thisweek article. FUTURE PLANS Wood Sample Storage Educational Display, Possible Site = New Community Center (?) School Presentations L:\ghove\2002file\misc\Eagan hist soc ancient wood memo ANCIENT WOOD REVEALS CLUES OF EAGAN'S PAST During well digging operations pieces of ancient trees were brought up from a depth of 300 feet that give a picture of Eagan's historical past. Five wood samples have been identified as tundra climate spruce wood that grew in a cold environment with a growing season of only about 3 weeks. These trees, probably growing next to a glacial river, date back to near the end of the last interglacial period, 75,000 to 130,000 years ago. These wood pieces have been preserved in sound condition under hundreds of feet of glacial till. These wood samples are on display inside Eagan's Community Center. ANCIENT FOREST DISCOVERED BELOW THIS LOCATION Wood pieces, dating back to 130,000 years ago, have been uncovered 300 feet below this location. Identified as slow growing tundra spruce, scientists have used these samples to create a picture of Eagan's ancient landscape as being similar to the current arctic Northern Canada. These wood samples are on display inside Eagan's Community Center. j Signs of ancient forest surface in Eagan Well -diggers unearthed small chunks of wood believed to be 50,000 to 2 million years old. Associated Press Well diggers in Eagan have discovered tiny chunks of wood 300 feet underground that sci- entists believe is evidence of an ancient spruce forest from a time when woolly mammoths roamed Minnesota. The wood is believed to be 50,000 to 2 million years old. University of Minnesota scien- tists are working to get a closer estimate of its age. "The people who live in that part of Dakota County probably don't know they have a little piece of history right below their feet," said Carrie Patterson, a ge- ologist at the university's Min- nesota Geological Survey. The wood was found Nov. 27 by well drillers at a munici- pal building site. A worker pulled up small chunks of wood at 198 feet and found bigger ones as he dug down to about 300 feet over the next week. Patterson examined sand and rocks that were brought up with the wood and concluded that two glaciers probably cov- ered the area at different times. In the place where the wood was found, a river valley once extended for miles through Da- kota, Hennepin, Scott and Goodhue counties. Scientists don't know how old it is. Trees in the area that is now Eagan were probably on the shore of the river. It turned into a lake, and the trees somehow wound up in the lake, although Patterson isn't certain whether they fell in or were shoved in by a passing glacier. The glaciers helped pre- serve the wood. The most re- cent glacier was probably the Superior Lobe, which came from the Lake Superior basin into the Twin Cities area 18,000 to 50,000 years ago. The earlier glacier came through the area about 150,000 years ago. But that information alone doesn't pinpoint the age of the wood. Robert Blanchette, a profes- sor in the university's Plant Pa- thology Department who spe- cializes in wood microbiology, determined that the wood was spruce, using an electron mi- croscope. He determined that the tree grew in tundralike conditions. Blanchette said the climate was so cold and harsh that the tree could grow only three - eighths of an inch in 30 years. sit PG-1 ItCJr a2,, CJJ 12- Z7-0( Anelent wood found in Eagan JOEL JURGENS, UNIVERSITY OF MINNESOTA A magnified image of the wood shows decay caused by microorganisms. Unearthed spruce bits hold clues about past BY MARA H. GOTTFRIED Pioneer Press Three hundred feet beneath Eagan, well diggers have discovered evidence of an ancient spruce forest that could be from a time when wool- ly mammoths roamed Minnesota. University of Minnesota scientists are now trying to piece together the mystery of how old the tiny chunks of wood are and what they reveal about how the region once looked. "The people who live in that part of Dakota County probably don't know they have a little piece of histo- ry right below their feet," said Carrie Patterson, a geologist at the Universi- ANCIENT WOOD, 11A Ancient wood (continued) ty of Minnesota's Minnesota Geological Survey. The wood, which is believed to be 50,000 to 2 million years old, can help scientists under- stand the history of an ancient local river valley, which could lead to new understanding about climate changes. "It helps us reconstruct the history of events," Patterson said. "This wood is just a little piece in a huge jigsaw puzzle." The pieces started falling into place Nov. 27 as well drillers dug where the city is building Central Park, northwest of Yan- kee Doodle and Pilot Knob roads. A worker pulled up small chunks of wood at 198 feet and found bigger ones as he dug down to about 300 feet over the next week. Patterson recently began try- ing to narrow down the age of the wood. By examining sand and rocks that were brought up with it, she concluded that two glaciers probably covered the area at different times. In the place where the wood was found, a river valley once extended for miles through Dakota, Hennepin, Scott and Goodhue counties. Scientists don't know how old the river valley is. Trees in the area that is now Eagan were probably on the shore of the river. That river turned into a lake, and the trees somehow wound up in the lake, though Patterson isn't certain if they fell in or were shoved in by a passing glacier. What preserved the trees for all this time were the glaciers that passed over the lake. The most recent was probably the Superior Lobe, which came from the Lake Superior basin into what is now the Twin Cities area 18,000 to 50,000 years ago. The other glacier probably came through the area about 150,000 years ago, Patterson said, but that still doesn't nar- row down how old the wood could be: No one knows how long the trees were there before the glaciers passed by. The work of examining the wood fell to Robert Blanchette, a professor in the Plant Patholo- gy Department at the Universi- ty of Minnesota who specializes in wood microbiology. It didn't take Blanchette long The wood is believed to be 50,000 to 2 million years old. to figure out the pieces were spruce. Working with research scientists Joel Jurgens and Ben- jamin Held, the scientists froze a portion of the wood and cut it very thin so it could be exam- ined under a scanning electron microscope. They determined the tree grew in tundralike conditions. When counting the rings on the tree, Blanchette noted that the climate was so cold and harsh that the tree grew only 3/8 of an inch in 30 years because it had only a few weeks a year to grow. Under the microscope, the wood's cell walls looked like Swiss cheese, Blanchette said. The wood was heavily decayed by microorganisms that attacked it while it lay in a body of water. As research continues, Eagan's forestry supervisor, Gregg Hove, said he's . thinking about sending the wood for car- JIM GEHRZ, PIONEER PRESS University of Minnesota geologist Carrie Patterson examines sand taken from the site of an ancient forest as she works in her second -floor office at the Minnesota Geological Survey in St. Paul. Patterson is trying to determine which of two glaciers deposited the sand in what is now Eagan. bon dating. But that might not yield more answers about the wood's age, because the tech- nique works only for objects that are 50,000 years old or less. Once Eagan completes con- struction on its community cen- ter, Hove said, he hopes to set up a display • there with the wood and its history. "This wood is a wonderful find, and it was purely coinci- dental, because if we had drilled five feet over, we may have never found it," Hove said. "When you think about what this wood may tell us about Eagan and the area long ago, it's just amazing." Mara H. Gottfried can be reached at mgottfried@pioneerpress.com or (651) 228-5262. Ancient timber Well diggers in Eagan recently found spruce wood while digging about 300 feet underground. The wood is 50,000 to 2 million years old and from an ancient river valley in the region, scientists report. In the area that's now Eagan, the river formed a lake and the trees likely fell in or were pushed in by a passing glacier. ® Ancient river valleys o Modern rivers Source: Minnesota Geological Survey ALEX LEARY, PIONEER PRESS Signs of ancient forest surface in Eagan Well -diggers unearthed small chunks of wood believed to be 50,000 to 2 million years old. Associated Press Well diggers in Eagan have discovered tiny chunks of wood 300 feet underground that sci- entists believe is evidence of an ancient spruce forest from a time when woolly mammoths roamed Minnesota. The wood is believed to be 50,000 to 2 million years old. University of Minnesota scien- tists are working to get a closer estimate of its age. "The people who live in that part of Dakota County probably don't know they have a little piece of history right below their feet," said Carrie Patterson, a ge- ologist at the university's Min- nesota Geological Survey. The wood was found Nov. 27 by well drillers at a munici- pal building site. A worker pulled up small chunks of wood at 198 feet and found bigger ones as he dug down to about 300 feet over the next week. Patterson examined sand and rocks that were brought up with the wood and concluded that two glaciers probably cov- ered the area at different times. In the place where the wood was found, a river valley once extended for miles through Da- kota, Hennepin, Scott and Goodhue counties. Scientists don't know how old it is. Trees in the area that is now Eagan were probably on the shore of the river. It turned into a lake, and the trees somehow wound up in the lake, although Patterson isn't certain whether they fell in or were shoved in by a passing glacier. The glaciers helped pre- serve the wood. The most re- cent glacier was probably the Superior Lobe, which came from the Lake Superior basin into the Twin Cities area 18,000 to 50,000 years ago. The earlier glacier came through the area about 150,000 years ago. But that information alone doesn't pinpoint the age of the wood. Robert Blanchette, a profes- sor in the university's Plant Pa- thology Department who spe- cializes in wood microbiology, determined that the wood was spruce, using an electron mi- croscope. He determined that the tree grew in tundralike conditions. Blanchette said the climate was so cold and harsh that the tree could grow only three - eighths of an inch in 30 years. Ancient wood found at new Central Park gives clues to Eagan's past by Erin Johnson Staff Writer While drilling hundreds of feet into the ground of Eagan's new Central Park, workers dis- covered something unusual: pieces of wood where wood isn't normally found. At about 200 feet below the surface, small pieces of wood showed up; a large chunk was found about 300 feet down. Sandwiched among layers of sand, clay and gravel, the dis- covery caught the attention of workers, who rarely find organ- ic material that deep in the ground. They collected the sam- pies and contacted the city with their find. The wood ended up in the hands of Gregg Hove, Eagan's supervisor of forestry. Hove ini- tially thought to have the age of the pieces identified through carbon dating, but was told that carbon dating is only effective on materials less than 50,000 years old. Hove next contacted Dr. Bob Blanchette, a plant pathologist at the University of Minnesota and Hove's former college advisor. "He thought it was pretty cool." Hove said. Blanchette identified the wood as spruce. He told Hove the wood existed in a frigid cli- mate that had a growing season of only a few weeks per year. It took 30 years for the tree to grow only 3/8 of an inch. It would take only one or two years for a tree to grow that much today, Hove said. Blanchette passed samples on to Dr. Carrie Jennings Patterson, a senior scientist at the Minnesota Geological Survey, which is part of the University of Minnesota. The wood is indeed a find, she said. "It is not common to have vegetation like this preserved," she said. Sea Wood, 20A two separate glaciers. Examinations of the wood led Patterson to believe the area was once a large river valley that was buried by a glacier. The valley eventually drained and a new valley was formed on top of the old one. The decaying of the wood is thought to be caused by water. When the tree died, it had been submerged in water until a gla- cier came and stopped the degradation, preserving the wood. Whether the wood was car- ried in with a flood and strand- ed in the area or had fallen in from nearby is unknown, Patterson said. Patterson tried to interpret the setting in which the wood existed to determine its age. She said she believes it probably dates back near the end of the last interglacial period, 75,000 to 130,000 years ago. "But it could be older," she said. What has amazed Patterson most about the wood, however, has been the interest it has gen- erated. She has been inter- viewed by several area newspa- pers, appeared on KARE-11's "Simply Science" and spoke on a Cities 97 radio show. Pieces of wood found at Eagan's Central Park date back thousands of years. The largest piece of wood is six inches long and two to three inches across. Submitted photo "What's been most surpris- ing is how many people are blown away by this idea," she said, adding that maybe geolo- gists need to make their find- =ings more public in the future. Patterson said the wood is a small clue in the larger picture of what the area was like many thousands of years ago. "It's a piece in a jigsaw puz- zle and that's what we spend our careers doing. We don't expect to figure it all out. We just expect to add our few pieces," she said. The wood has been returned to the city, which is looking into setting up an interpretive dis- play at the new Community Center with the Eagan Historical Society. The display will require special care so the wood isn't exposed to oxygen. Hove plans to discuss ideas with a company that specializes in geologic displays. S trmRb PAN 4 YS Lc' KV 5d 61) 'tAClC Fici,,_/ Dest't SANC) To 4'0 TO to* ticr ILO tab ►ko 1 ct1 *0 17D SRN GizAvet - • 14AL X PAN srnnct, ur+ro0 1/'' 6Ckr4SS tZetOS ®\tD l E &6rTt)'\ STutf( �� vo tvo ago cAut,tKi ' Stti ..Pee JOG )1n 3 346 30 3-7ck 3r0 3112 wcsdz] , stteu.s 1.4A-Pse tutlon PEce rt.(,R SHRK.OPeC Ji 12 01 UtAke STvtvt:i ((a-L (j./kccr,".S1;.\0-"`• /(`cLc"...) (moo-^ if SeJ(Qwl. tcL. T; (( r\—w- s )t.rect n.. SK1,a ICA-- cr c 41 eP*fls1 .. SL./Le,;ca'.-L°Le (\ov(k uec.d, SU"u ci,ae•Sr ( e SU.a«Uw (c fiLcivir(C. cLQ (o{1 Ur wry, (ck2 (Ox- ) -- ct 10A dY cLC {� Wwr ac /p(o %. Luc %**Tetc**: (Lek 'm.JJ = roc k.1 41r(A` fig t((k‘ S ((le S UNIVERSITY OF MINNESOTA Twin Cities Campus December 17, 2001 Mr. Gregg Hove City of Eagan 3501 Coachman Point Eagan, Minnesota 55122 I)ear Greg, Department of Plant Pathology College of Agricultural, Food. and Environmental Sciences 495 Borlaug Hall 1991 Upper Buford Circle St. Paid. MN 55108-6030 612-625-8200 Fax: 612-625-9728 E-mail: plea@puccini.crl.umn-edu http:/lwww.plpa.agri.umn.edu The wood samples recovered from approximately 300 feet below ground during the well drilling in Eagan have been examined and identified. All of the samples have anatomical characteristics of spruce. Sections of the wood indicate that is has been extensively degraded. The wood has degradation patterns of soft -rot fungi (which cause spiral cavities to form in the cell walls) and bacteria (causing an erosion and minute tunneling in the wood). Our previous work on fossil wood in the arctic, buried archaeological woods and waterlogged woods (sunken logs in lake superior, sunken ships, etc.) provides information that allows these decay characteristics to be identified. They are not the types of decay found in a typical forest ecosystem, instead they are what would occur if the wood had fallen into a lake or river and became waterlogged. The soft rot fungi and bacteria attacked the wood slowly as it was on the river or lake bottom. The amount of decay present in the wood indicates the wood was submerged for many years (most likely decades). Since the largest wood sample also has rounded edges and a smooth surface it resembles wood that was eroded by water in a river system. The surface of the wood also has evidence of mud adhering to it despite being found in a sand -gravel environment at the drill site. The sediments from the glacier buried the wood and established anaerobic conditions that inhibited further decay and served to preserve it. A cross section of the small branch wood among the samples indicates that the trees were growing in a very different environment than found today. The annual rings are very small and consist of only a few cells. In the branch, with a diameter about the size of a small finger, there are almost 30 annual rings present. This indicates the tree was restricted in its annual growth and most likely was living during a time when there was an extremely short growing season that may have consisted of only a few weeks. The 300 feet of sand and gravel were deposited on top of the wood during a past glaciating event. For information about Minnesota's past geology you may want to talk to Carrie Patterson at the University (Minnesota Geological Survey) at 612-627-4780 ex 220. She indicated to me that this wood was probably much older than 50,000 years and it would not be possible to use radiocarbon dating for this. She also indicated that it is quite possible that it is well over a million years old. Page 2 To summarize, this wood was from very slow growing spruce trees living in a very growth -limiting environment. These pieces of wood had fallen into a river or lake and became waterlogged. While they were on the river or lake bottom they were subjected to decay organisms specific to this environment. After many years they were displaced and covered by glacial till. I suspect that 300 feet beneath Eagan there is an ancient river and or lakebed filled with remnants of an ancient forest that once covered this part of Minnesota. These woods provide a glimpse of what that forest was like and the environment that they lived in. We are providing a few scanning electron micrographs so you can see the unusual characteristics of this ancient wood. In addition to myself, Mr. Joel Jurgens and Mr. Benjamin Held, research scientists wording on my project, helped to mount, section and examine the woods to get these results. Sincerely, obert A. Blanchette Professor UNIVERSITY OF MINNESOTA Twin Cities Campus Minnesota Geological Survey Institute of Technology January 11, 2002 Mr. Greg Hove City of Eagan 3501 Coachman Point Eagan, Minnesota 55122 Dear Greg, 2642 University Avenue St. Paul, MN55114-1057 612-627-4780 Fax: 612-627-4778 E-mail: mgs@gold.tc.umn.edu Thank you for the opportunity to look at the wood you found and for putting me in touch with Bob Blanchette. As you know, articles have appeared in the Pioneer Press, Minneapolis Star Tribune and Duluth paper. I was taped for "Simply Science" on KARE 11 (I am not sure when this will air if it has not already) and will be interviewed on this topic on Wed. Jan. 16 at 8:20 AM on the Cities 97. Today I was also in touch with Jessica Mandole of the Science Museum. She has probably already contacted you about a small display there. There was much more interest in this topic than I imagined. First I will outline the information I was able to glean from the drillers' daily logs and from looking at the sand that you sent me. Of course, it is always best to see the material first-hand but these are my interpretations based on the information given me. After I describe the log and my interpretations, I will place this information in a larger context. 0 - 40 Drift/Sand, brown. Interpretation: Sandy, reddish brown till of the Superior lobe. Late Wisconsinan glaciation. 40-77 Sand, brown. Interpretation: Stream sediment of the Superior lobe. 77-82 Sand and gravel. Interpretation: Coarser (nearer the glacier or higher energy) stream sediment of the Superior lobe. 82-95 Hardpan, brown. Interpretation: Another reddish brown, sandy till of the Superior lobe. We know that the Superior lobe was in this position at least twice during the Late Wisconsinan glaciation. 95-97 Sand: Interpretation: Stream sediment. 97-145 Hardpan, sand /trace of clay, brown. Interpretation: Till of the Superior lobe. This is not an unusual thickness of till given the location in a moraine. 145-160 Sand and gravel, layered, brown. Interpretation: Stream sediment of the Superior lobe. 160-189 Sand, gray, sand and gravel, brown. Interpretation: Unoxidized stream sediment and oxidized stream sediment of the Superior lobe. Alternatively, we may be in the stream sediment of a glacier with a 189-198 different source for its debris and the gray color is reflecting that change in source area. Hardpan, gray, trace sand and gravel. Interpretation: Older, gray till with a northwest source. We unimaginatively call this till the "old gray till". Then the drillers changed bits and bailed the hole. The also drove casing to 190.34' before continuing drilling (as I read the log). 198-213 Sand (gray)/wood. Interpretation: Stream or beach sand with wood. The wood that I received actually had sand grain imbedded in it and as Dr. Blanchette noted, was rounded indicating it had been transported. 213-235 Sand (gray)/wood/decomposed grass reeds. Interpretation: deposits of a floodplain or shallow lake. 235-250 As above 250-260 As above, "lake bottom stuff'. Interpretation. Deposits of a deeper lake or pond. This could be a cutoff meander lake or "oxbow" given its location in a buried bedrock valley or a "side lake" similar to the modern lakes on the Minnesota River floodplain that form behind the levees. 260-265 Sand, gray. Interpretation: stream sediment. 265-272 Sand, gravel, clay chunks, wood,shells. Interpretation: deposits of a lake or backwater on a flood plain. Clayey sediment is either in place or ripped up and redeposited by the stream that deposited the sand and gravel. 272-282 Sand, gravel, chunks of clay, shells, wood, rocks. Interpretation: as above. 282-290 Same stuff with chunks of Shakopee: Interpretation: Colluvium in stream sediment. This means that angular pieces of the local bluff - forming rocks fell into the stream and were not transported far before being buried by additional stream sediment. This indicates that the stream had moved to a position in its valley where it was impacting the channel wall. It could represent a flood event or rerouting of the stream. Given the nature of the sediment above this, the water flowing in this route was soon lessened to the point where the channel filled with finer sediment and became overgrown with reeds. The wood in this case would be drift wood in the stream. 290-295 Sand, light traces of gravel. Interpretation: stream sediment. 295-298 Gravel. Interpretation: coarser stream sediment 298-304 Sand, gravel, wood, chunks of Shakopee rock. Interpretation: stream sediment with colluvium (from rocky slopes) and either drift wood or wood that fell with the rock. 304-338 Sand, gravel, brown. Interpretation: stream sediment. 338-340 Shakopee (bedrock) The sample that I was given did not have a depth written on the bag. I am unsure where it came from exactly. However, there were no diagnostic grains in it that would indicate which glacier it was associated with. It is predominantly quartz. The quartz grains are angular to sub -rounded and clear, originating from a disaggregated granitic rock or saprolite to well-rounded and frosted, originating from the local sandstone bedrock. Quartz grains as well as the other types of sand grains found in this sample are resistant to physical weathering and survive vigorous and prolonged transport. Other grains included in the sample were local carbonate bedrock, iron -coated grains, feldspar and traces of dark, heavy minerals. The sand ranged from very fine to very coarse. I looked mainly at the 1-2mm sized sand grains for identification purposes. There may have been a couple of grains eroded from Cretaceous sands of the Ostrander formation. These grains have a characteristic polish. As you already know from the location of this drill hole with respect to the bedrock topography, the sand and gravel is associated with a buried valley carved into the bedrock. As far as we (I have discussed this with other survey geologists including Howard Hobbs and Gary Meyer) can tell, this bedrock stream was the master stream during the last interglacial and probably even prior to that. It is deeper and wider than the modern Mississippi but probably drained a similar area in central Minnesota. We interpret the greater depth and breadth to indicate that it existed for longer than the current, 10,000-15,000 year -old channel. According to the sequence of units in yoWhole, this valley was filling with sand and gravel that it was transporting. This could be just the normal bedload of the stream or it could represent the increase in sediment load due to an advancing glacier. I kind of favor the latter interpretation because of the cold climate indicated by the tree rings. In any case, the stream also hard chunks of the local bedrock falling into it at times. This probably means that it had somewhat steep bedrock walls. Then we see evidence for a lake forming near the river. This could either be an oxbow lake (cutoff meander) or a levee -dammed lake (side lake). It is still getting occasional deposits of sand and gravel so it close to the stream, but also has shells, reeds and grasses indicating that it is still and ponded some of the time. The wood is either carried in during flood events and gets stranded there or has fallen in from nearby. It is impossible to tell. We know from Dr. Blanchette's work that it was submerged in water as it decayed. Then a thin layer of gray till was apparently deposited over this stream sediment. It is possible that this till was also colluvial (meaning that it, too, fell from the valley walls to this position). The bulk of the material covering the channel fill is till and associated stream sediment from two advances of the Superior lobe. It is especially thick in this location because Eagan is located where the glacier stopped, depositing a thick end moraine. The wood is most likely from the end of the last interglacial and beginning of the Late Wisconsinan glaciation. It is definitely older than the St. Croix moraine, deposited approximately 20,000 years ago, most likely older than the first advance of the Superior lobe, not well dated but likely 30-40,000 years old, and probably dates to near the end of the last interglacial, 130,000 to 75,000 years before present. If you decide to have Beta Analytical get a radiocarbon date, have them do an extended count to push the date as far back as possible. It will most likely yield a "greater than the limit" date but even that could help to constrain our story. If there is anything else that you would like me to look at (gamma log, more drill cuttings) I would be happy to. I am including the business card of Kate Pound with Earthfolio. She is the person that I recommended help when you are ready to develop your interpretive display. Sincerely, Dr. Carrie Jennings Patterson Senior Scientist Minnesota Geological Survey 1 { pre2-`168hait-11 a !+ ` fife 5 �" tom. 4. • 0 ■ � ♦ •• • c n i . 1 . ©1 x.2.Ok 2Oum .'