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Minnesota Sesquicentennial Commission Grant Project conducted by the Geological Society of Minnesota to install or update seven Historical Markers at designated State Park Locations. 

 

Title                                  August 5, 2009
   

                                                    August 5, 2009

A complete and final report of the Project will be submitted to the Minnesota Historical Society by August 31, 2009.

The following is an accounting of encumbered funds by State Park location.

Split Rock    …………………… $3968.00

Interstate ……………………..    2538.17

Gooseberry Falls …………….  2613.17

Flood Bay ……………………….  2778.17

Frontenac   …………………….. 4800.17

McCarthy Beach …………….  6322.17

Beaver Creek …………………  3421.17

 

Total encumbered funds   $26441.02

Being that the Grant totaled $40000.00, the difference of $13558.98 is to be returned to the State per your instructions or we can apply the difference to additional State Park locations as will be determined, if authorized to continue the project.

Please advise us if any additional information is required to continue the project or if needed prior to our final reporting August 31, 2009.

Edward B Steffner, Project Manager

Doug Zbikowski, Project Director

SPRING 2008 VOLUME LXII NO. 1

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FALL 2006 VOLUME LX, NO. 3

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SUMMER 2005 VOLUME LIX NO. 2

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FALL 2005 VOLUME LIX NO. 3

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SUMMER 2004 VOLUME LVIII NO. 2

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WINTER 2004 VOLUMN LVIII NO. 4

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GSM Newsletter AUTUMN 2003 VOLUME LVII NO. 3

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SUMMER 2003 VOLUME LVII NO. 2

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Newletter Logo SUMMER 2003 VOLUME LVII NO. 2
   

 

DNR MINERALS TEACHER EDUCATION WORKSHOP Aug 5-7

 

Annual three-day workshop offers geology and earth-science training for K-12 teachers, parents that home school, and other educators. It consists of one day of classroom sessions; 1-1/2 days field trips and mining tours. Topics include general geology, rock and mineral ID, and mine reclamation. Held in Hibbing, $30, space is limited. Interested?  Visit:

<http://www.dnr.state.mn.us/education/geology/workshop/index.html> call (651) 296-4807; e-mail vicki.hubred@dnr.state.mn.us

 

Minnesota Geological Survey Faces Budget Cut as Legislature Faces Deadline

 

    The Minnesota Geological Survey is facing a budget cut of at least 8% for the coming two years as state lawmakers enter the final stage of wrestling with the state budget.

    The Legislature must adjourn on Monday, May 19, under the Minnesota Constitution. As this newsletter goes to press, most key budget decisions remain unresolved.

    The MGS is funded through the University of Minnesota’s budget bill.  The budget request submitted to the Legislature by Gov. Tim Pawlenty included deep cuts in funding for all higher education institutions.  Gov. Pawlenty’s recommendation cut the part of the U of M budget that funds the Survey by 14% below the 2003 level.  This would have cut the survey by $168,710 a year for the next two years - to $1,036,359 annually in each of the next two years.

    Republican lawmakers, who control the Minnesota House of Representatives, passed a higher education budget bill that restored some of the cuts proposed by the Governor.  Under the House bill,  MGS would lose a little less - about $150,000 per year.

    DFL lawmakers in the state Senate passed their version of the higher education budget bill with $100 million more than the Governor proposed.  However, it still cuts funding to the Survey by about $125,000 a year in each of the next two years.

Because the House and Senate passed wildly different bills, a conference committee - which consists of five House members and five Senators - has been appointed to negotiate a compro-mise package that can be re-passed by both sides of the Legis-lature and sent to the Governor’s desk.  As of May 12, no progress had been made.

    The budgets for the agencies that use the Geological Survey - including the Department of Natural Resources, Pollution Control Agency, Department of Health and others - likewise remain in limbo with the adjournment deadline less than two weeks away.  As with the higher education budget, the House and Senate passed budget bills with significant differences on funding and policy.

    Should the Legislature fail to pass a state budget package by the constitutional adjournment deadline of May 19, two things can happen:

 

  • The Governor can call lawmakers back for a special session to continue to work toward agreement, or
  • If there is no special session (and only the Governor can call one), or if there is no agreement in a special session, state government would completely shut down on July 1.  The state’s two-year budget cycle ends on June 30, and with no budget bills enacted, there would be no legal authority to spend money for any state government activity.

~Tom Smalec

Some of you asked for the source of the Image in the first slide of Howard Hobbs’ presentation on 4/21/03.  It is located here: <http://www.jpl.nasa.gov/srtm/northAmerica_radar_images.html>

 

President’s Letter…

Since this is the end of our lecture series for 2002-2003, this seems to be a time for a whole lot of thank yous.

First, thanks to all the wonderful lecturers who worked so hard and taught us so much.  We’re also grateful to Rick Uthe, who put together the series on the “Fascinating Geology of Minnesota”.  We are grateful to the Minnesota Geological Survey staff who let us use their facility for all of our lab sessions, and who provided the geologists to deliver 13 of our lectures and labs. Where would we be without them!  (I hope we don’t soon have to find out.)

Thanks to the GSM Board and members and to former President Steve Erickson for the assistance they have given Rick in preparing  next year’s interesting lecture series, entitled “Geologic Landscapes”.

Thanks to members who serve on various committees of the society, and to all members, whose membership fees enable us to offer honoraria and reimbursed expenses to our speakers.

Plans are well underway to make our booth at the State Fair more attractive than it has been. Thanks to the Mattsons, long time members who supported this financially,  and to Roger Benepe, Tom Schoenecker, and Bruce Goetteman, who are making this plan a reality.  Thanks in advance to the people who will help by offering to staff our booth during the fair.

Doug Zbikowski continues to lead our Public Service Committee, while Bill Farquhar has taken over the education part of that committee.  Ted Chura does more than his fair share as he’s our treasurer, and heads our video library.

Gail Marshall is no longer on the Board, but she’s as active as before. She’s our Membership chair, and is one of the prime organizers for our summer field trips. Please support her and her partners in organizing: Diane Lentsch, Dick Heglund, and Steve Erickson. The three field trips still to be held this summer should be great.

After you look at our Website < www.geo.umn.edu/ orgs/gsm/>, thank Alan Smith for all he does to maintain that informative site.

Former president Bill Robbins’ wise counsel is always helpful, and an additional thank you to Bill for preparing the new 2003 directory.  Our continued gratitude goes to Katy Paul who prepared this newsletter, and effective with the August edition, has turned over the editorship to Tom Smalec.  Thanks for all you’ve done Katy!

I have not forgotten Judy Hamilton, our secretary, but will say more about her when her term of service is over, at the end of this year.  I apologize in advance to anyone whose name I omitted.

If you want your name to be on a list like this next year, or if you just want to become more involved in the work of the society, please know that you are very welcome to join in the fun, and work. Phone or email me or other Board members (phone numbers and emails in the directory).

           

                                                                        ~Paul Martin, President

Vertebrate Paleontology 

Society of Veretrate Palteontology Meeting 

Complaining About Gas Prices?

By Terry Almsted, Fredericksburg TX

The price of a gallon of gas is up again. Our daily lives are so dependent upon petroleum products, and so we complain about the rising prices. I'm a native Minnesotan who, by the quirks of fate, got involved with the oil industry years ago, and thought it might be interesting to the members of the GSM just what is involved in looking for oil these days. If I was addressing an audience of people living on the Gulf Coast of the United States, this would be general knowledge, as everyone living there has a cousin, neighbor or work themselves in the oil industry. Minnesotans are a different story, the oil industry is rather a foreign subject.

My experience is in one part of the oil industry, exploration. Along with it are production, refining and transporting to the customers, so I speak of one small part of the whole picture. It’s quite an amazing industry, and I wish I could write of all the people involved in getting a gallon of gas to the pumps, but here I hope to just enlighten you on the search for oil.

These days, most exploration takes place offshore.  The easy areas, dry land, have been surveyed already. The beginning of exploration is a guess as to what might be a likely place for the right conditions for oil to be trapped. A seismic survey ship will be hired to gather data at the area in question. The process of determining what lies in the twenty thousand feet of rock, sitting under a few thousand feet of water, is what offshore exploration is all about. A seismic boat has four main divisions of equipment: the seismic sources, the recording system, the processing system, and navigation. All of these work together to get a picture of what's down there, and even then, after all is said and done, it doesn't guarantee oil is there, only that the rock formations may be capable of trapping oil.

The seismic sources are typically referred to as air guns, as they release air, compressed at 2000PSI, to create a shock wave that travels down through the water, and through the rock layers. It reflects back to the surface as it encounters various faults and density changes. The guns come in different sizes, each one creating a specific frequency content in the shock wave, and they are placed out in the water in an array of up to 100 individual guns. Each gun is roughly equivalent to a stick of dynamite going off when it releases its high pressure air. Indeed, 2000PSI is capable of blowing a hole through a human body. Safety is a major concern around the guns. To gather good data, all the guns in the array must fire at the same time, i.e. within a thousandth of a second of each other. That is where I do my work. I build the electronics that control the gun timing. The guns are towed about 200 meters behind the ship, on what are called strings. At the far end of the strings, are GPS receivers, to tell the boat exactly where the guns are when they fire. Also, each string has electronic instruments to tell the operators exactly what depth in the water the guns are at, as this is critical. Large tubular floats, each about the size of a civil war cannon, and large enough to crawl through, support the guns in the water.

Towed behind the guns, and extending out nearly a quarter mile either side of the ship, and to a length of over a mile, are very sensitive underwater microphones, called hydrophone streamers. To maintain their position, this quarter mile out from the sides of the ship, devices called paravanes that are like kites in the water, pull the streamers outward. The tension on the streamers is monitored constantly, as too much or too little indicates problems. The tension on pulling these streamers through the water is about 2 or 3 thousand pounds each streamer.  There is so much drag from towing all this stuff through the water, that the ship burns about 8000 gallons of diesel fuel per day.  (They're their own best customer). The shock waves generated by the seismic guns are reflected back from deep in the ground under the water, to these streamers of hydrophones. Then the data is converted  to an electrical signal, which is sent by cables to the recording system on the ship.        

There will be thousands of hydrophones in a single streamer, and each streamer is valued at over $100,000.  Like the guns, they must be at a certain depth.  Too shallow, and they get too much noise from wave action; too deep, and they get reflections from the surface that confuse the data. To maintain the correct depth, a ”bird” is placed every so many meters along a streamer. A bird is a cylindrical instrument that has wings that can be controlled from the boat, to cause the streamer to dive or to rise. For the birds to work correctly, the streamers must have near neutral buoyancy. This is accomplished by mounting the hydrophones inside oil filled plastic tubes, the oil being lighter than water. Every job done requires varying the amount of oil, to compensate for differences in water temperature and salinity.

At the other end of the hydrophone streamers, is a recording system. Every time the guns fire, for five seconds, or so,  the recording system tapes the data from all the hydrophones. The amount of data is phenomenal:  gigabytes each shot, terabytes to the max each job. Each shot requires the logging of the GPS data of each gun string, and of course each hydrophone streamer has a GPS receiver to be recorded.  Also recorded are depth data, air pressure on the guns, and gun timing data, should a gun be out of time by a couple of milliseconds.

In the old days, no processing was done on board the ship. But now, with the advances made in electronics, a lot of data is processed to a point where it can be determined that all is well with the information being gathered. The data from each hydrophone shows up as a squiggly line when printed, and compensation must be made for such things as its distance from the seismic guns. The interpretation of the data is well beyond my explanatory capabilities. The data is organized in conjunction with the navigation of the ship. What is called a seismic line is steered by the ship, again with help from GPS. This line is simply a course the ship follows, and may typically be about 50 miles long. As the ship follows this line, the guns are fired by the GPS navigation system every 50 meters, or so. At the end of a line you may have fired the guns a few thousand times. A whole prospect survey may encompass 50 or 100 lines to be navigated. Because the streamers are a mile or more in length, for the ship to end one line, turn around, and come onto a new line, requires about 4 hours, and the lines themselves are about 12 hours long. You just can't turn around sharply, or you'll tangle your streamers. Each line surveyed costs the client about $150,000, and since you can do 1 or 2 lines a day, any hours lost due to a tangle in your streamers, or guns failing, or a fishing boat crossing your streamers and cutting them off, rapidly mounts up in the dollars category.

 

Besides the technical people operating the seismic systems, there is the ship’s crew. They keep the boat moving, keep the technicians fed, and maintain a safe and clean environment. Everyone works 12 hours on, 12 off; heck, there isn't anyplace to go after work anyway. Its an interesting amalgam of people. For example, my last trip involved a Louisiana company-owned ship, leased by a Russian geophysical company whose technicians operated the seismic systems, with a mostly Philipino crew, and with Brits, Scots, Australians, Americans and Canadians installing the systems and teaching the operators, and the company hiring the boat was from India, so the company reps were Indian. Every-one must have respect for the others, the ship is only 300 feet long, you can't hide from the society onboard. Courtesy and honesty are rampant. The staff onboard, crew and technicians, normally stay for about 60 days, and get rotated out with a relief crew. Then its fly home for a few weeks, and back out to another job. I'm lucky, I just teach and install, usually on and off in 2 weeks, but for most, its a mighty long commute to work.

I hope this makes you feel a little better next time you fill up your tank. A lot of people, from all cultures and nationalities had a hand in bringing this energy to you. All the easy oil has been found, what's left is in the remote and deep areas of our planet. And don't forget the motto of the oil industry: There's no fuel like an old fuel.♦  

You know you’re an ardent fan of geology when...

  You ARE watching for rocks.
  You consider road cuts tourist attractions.
  You expect collection site information with your jewelry.
  Your favorite necklace is made by Bausch & Lomb.
  On returning from vacation, the front wheels of your car are almost off the ground.
  You don't think of "cleavage" the same way everyone else does.
  You look at the stone facades of buildings with your hand lens.
  You knew the rock was obsidian in "The Shawshank Redemption".
  You use a pick and shovel while you're on vacation.
  The baggage handlers at airports know you on sight and refuse to help you with your luggage.
  You associate the word "hard" with a value on the Mohs scale.
  You associate the word "saw" with diamonds instead of "wood".
  Your home page has images of rocks.
  You think Herkimer, New York might be a cool place to go on a vacation.
  You follow when you see a university's geology class going on a field trip.
  You associate the name "Franklin" with New Jersey instead of "Ben".
  Your children are named Rocky, Jewel, Crystal, and Beryl.
  You've taken a copy of Dana's Manual of Mineralogy to the bathroom.

 

From the Editor:  Its been fun, but I have decided that it is time for a change, time for someone else to take over the newsletter.  Tom Smalec has graciously agreed to do this.  So with this issue, I’ll be turning over the Editorship to him.  But don’t think that you won’t see any more articles from me in the newsletter.  Tom doesn’t know it yet, but I plan to deluge him with articles.  And I hope that other members will do the same.  The newsletter editor’s job is very difficult when there is nothing to publish.  And a newsletter written solely by one person can get pretty stale.  So please submit articles and ideas to Tom. The newsletter represents ALL the membership, and all the membership can submit things for consideration.  No guarantee that everything submitted can or will be used, but it sure is great to have choices.

                       ~Katy Paul

 

WOMEN IN GEOLOGY:  Inge Lehmann

 

     Inge Lehmann (1888 – 1993) was born in Denmark, on May 13, 1888.  In 1920 she earned her master's degree in mathematics. After 12 years of undergraduate and graduate studies at the University of Copenhagen and University of Cambridge, studies that were interrupted by 6 years of full-time actuarial work, she earned a second master's degree in 1928, in geodesy, from the University of Copenhagen.

     Lehmann's career in seismology began in 1925 when she aided N. E. Norlund as he established seismic networks first in Denmark, then in Greenland. By 1928, Lehmann was named the first chief of the seismology department of the newly established Royal Danish Geodetic Institute, a position she held for 25 years.

     In 1936 she published the paper that sealed her place in the history of geophysics. Known simply as

"P' (P-prime)," the paper suggested a new discontinuity in the seismic structure of the Earth, now known as the Lehmann discontinuity, a region that divides the core into inner and outer parts. Using ray theory and travel time curves to interpret seismograms, Lehmann discovered that the P' phase of seismic waves traveling through the inner Earth was not the result of diffraction, the commonly held interpretation at the time, but a clear indication of an inner core.

     Later, Lehmann established herself as an authority on the structure of the upper mantle. Extended parts of her later years were spent as a visiting scientist at the Lamont-Doherty Earth Observatory, Dominion Observatory, the Seismological Laboratory at Caltech, and the University of California, at Berkeley. She also led her colleagues as a founder and president of the European Seismological Federation, president of the Danish Geophysical Society, and vice president of the International Association of Seismology and Physics of the Earth's Interior.

     In 1971, Inge Lehmann was presented with the William Bowie Medal, the American Geophysical Union's highest honor, which is granted to a scientist who has made fundamental contributions to the study of geophysics and who has lived up to the AGU ideal of unselfish cooperation in research. Lehmann also was named an AGU Fellow and was awarded honorary doctorates from Columbia University and the University of Copenhagen. ♦

 

☼ ☼ ☼ ☼ ☼  IT'S STATE FAIR TIME AGAIN!  ☼ ☼ ☼ ☼ ☼

It’s a little early, but think STATE FAIR.  The Show and Exhibits committee is now working on a revision to our booth at the FAIR.  We hope it will be enough of an improvement to make your time in the booth more pleasant.

In the next two months, the committee will be putting together the roster of workers for this year’s booth.  We will need 72 people to work the booth during the fair.  The fair will be from Thursday, Aug. 21st through Monday, Sept. 1st.  Each day will be divided into three shifts.  The shifts will be from 9 AM to 1 PM, 1 PM to 5 PM, and from 5 PM to 9 PM.  We will need two people per shift.

We know that the May Newsletter may be a little early for you to start planning, however, the August newsletter would be too late.  So why don’t you check your schedules, pencil in a good date, and call Tom Schoenecker at   952-474-4600, and have him reserve that time (or a good substitute) for you.  HURRY BEFORE ALL THE GOOD TIMES ARE GONE.  Tom will send you a reminder before the fair starts.

Remember, you don’t have to be a Geological Genius, but just have an unbridled interest in Geology, and just plain old Rocks, to work the Fair.  Your job at the fair is to invite those with the same interests to our lectures and field trips.  Membership will hopefully come from that.

 

FIELD TRIP SCHEDULE – 2003

June 28-29   Baraboo Area of Wisconsin                           contact Dick Heglund

                        Leader:  Phil Fauble

                        Wisconsin Department of Natural Resources

July ??         The Great Mississippi River Road                             contact Gail Marshall

                        Dubuque, Iowa to Saint Paul, Minnesota

                        Leader:  Ian Williams, University of Wisconsin (tentative)

August 17   Geological Walking Tour of Saint Paul                contact Steve Erickson

                        Guides:  Science Museum of Minnesota

                                    Geological Society of Minnesota

                                      Minnestoa Mineral Society

Final details of each field trip will be provided to members in a mailing, approximately three weeks before the trip.  Questions prior to that time may be directed to the contact person listed above. ♦

Summer 2002 Volume LVI NO. 2

Posted in
Newsletter Photo Summer 2002 Volume LVI NO. 2
   

 

FASCINATING GEOLOGY OF MINNESOTA:
FROM A gates TO Z eolites

 

Just wait until you see the outstanding Lecture Series we have coming up for the 2002-2003 season!  The Program Lectures and Labs committee has put together a lineup of presenters that reads like a “Who’s Who of Minnesota Geology”.  If you have not been in the habit of attending lectures in the past, you may want to pay close attention to this series.  It is not to be missed.

 

The Lecture Series Schedule will be published in the next issue of GSM News (Aug. 15th), so you’ll have to wait until then.  But here’s a tiny hint:  if you’ve ever read works by Richard Ojakangas or John Green, and wished you could ask questions in person, you are going to be pleasantly surprised.

 

 

News from the Board…

 

 

Greetings!

 

            I am very pleased at the end of this lecture set, for the year 2001-2002.  This had started with something of a disaster, with the State Employees strike, causing some quick reworking of the schedule.  We had to cancel one lecture due to bad weather, but still, we managed to cover a lot of very interesting topics this year.  I am pleased with the turnout to the lectures, but, I still don’t think we are reaching all the people who would have liked to have heard these seminars.  The board has talked repeatedly about how to get the message out to the general public about our mission and our activities.  I  am always open to suggestions.  One of the most important points of contact with the general public is our booth at the Minnesota State Fair.  We need volunteers to man the booth.  You do not need to be a geologist to do this.  We do not attempt to be the source of “Geo-wisdom” at the fair.  All the volunteers do is promote the organization.  Please call me if you are interested in participating in meeting the public and/or setting up the booth.  When I first did this, I thought it might be boring to stay in one space for a four hour shift.  It turned out to be a lot of fun, and I met some old friends who walked by.  

 

             This summer looks like we will have a great set of field trips.  My thanks to the members of the field trip committee for all their hard work.  I hope all of you can get away for as many of these trips as you can.  Please be prepared to team up with other members of the group to car pool.   This is a great way to meet new people and this makes the trip operate more smoothly.  

 

                                                                Steve Erickson, President

 

 

 

AGATE CENTER CONSTRUCTION BEGINS

 

     Moose Lake State Park broke ground on Saturday, April 6, for a summer-long project that began the construction of the Moose Lake Agate/Geological Center, which is expected to be completed this fall. 

 

     The 4,500-square-foot Agate/Geological Center will include interpretive displays, a multi-purpose classroom, nature store gift shop, park offices, a resource workroom, restrooms and an exhibition hall that will showcase Minnesota's gemstone, the agate. When completed, visitors will be able to view exhibits and attend programs that focus on the rocks, minerals and geology of Minnesota. 

 

     A centerpiece of the new facility will be an entrance area floor inlay that will be fashioned in the shape of the state of Minnesota. Stone inlays will be set in geographic areas of the state that reflect the type of rock indigenous to the area. 

 

     Moose Lake State Park, and the future Agate/Geological Center can be found by exiting I-35 at Exit 214; then head east on County Road 137 to the park entrance.

 

 

 

COLOSSAL CRYSTALS

 

In April 2000, Eloy and Javier Delgado were blasting a new tunnel, 1,000 feet down in the silver and lead Naica Mine of southern Chihuahua, Mexico.  Eloy climbed through a small opening and found a 30- by 60- foot cavern choked with immense gypsum crystals, the length and girth of mature pine trees.  He said that the sight was beautiful “…like light reflecting off a broken mirror”.  The translucent crystals lie pitched atop one another, as though moonbeams suddenly took on weight and substance.  One month later, another team of Naica miners found an even larger cavern adjacent to the first one.

 Officials of the Penoles Company, which owns the mine, kept the discoveries secret out of concern about vandalism.  Not many people, however, would venture inside casually:  the temperature hovers at 150 degrees, with 100 percent humidity.  A person can stay inside the cave for only six to ten minutes before becoming disoriented.

 Geologists conjecture that a chamber of magma, lying two to three miles underneath the mountain, forced mineral-rich fluids upward through a fault into openings in the limestone bedrock near the surface.  Over time, this hydrothermal liquid deposited metals such as gold, silver, lead and zinc in the limestone bedrock.  These metals have been mined here since prospectors discovered the deposits in 1794 in a small range of hills south of Chihuahua city.

 In a few caves the conditions were ideal for formation of a different kind of treasure.  Groundwater in these caves, rich with sulfur from the adjacent metal deposits, began dissolving the limestone walls, releasing large quantities of calcium.  This calcium, in turn, combined with the sulfur to form crystals on a scale never before seen by humans.

 In addition to 4-foot diameter crystal columns 50 feet in length, the cavern contains row upon row of shark-tooth-shaped formations up to 3 feet high, which are set at odd angles throughout.  This crystal form of the mineral gypsum, is known as selenite, named after Selene, the Greek goddess of the moon.  The superintendent at the Naica mine has speculated that under perfect conditions, the crystals would have taken between 30 to 100 years to grow.  Previously, the world’s largest examples of selenite crystals came from a nearby cavern discovered in 1910 within the same Naica cave complex.  Several examples of these large crystals are exhibited at the Smithsonian Institution’s National Museum of Natural History.

 Until April 2000, mining officials had restricted exploration on one side of the fault out of concern that any new tunneling might lead to flooding of the rest of the mine.  Only after pumping out the mine did the level of water drop sufficiently for exploration.  Everyone who knows the area is now anxiously awaiting the possible discovery of new caverns with even more fantastic crystal formations.

 

Excerpted from Smithsonian  Magazine,  April 2002

 

 

 

GROUND BREAKING FOR UM EARTHQUAKE TESTING FACILITY

 Earthquake Testing facility

 

>Wielding shovels to break ground for the U of M’s new earthquake testing facility on the Minneapolis campus are: President - Mark Yudof, Vice President for Research - Christine Maziar, Institute of Technology Dean - Ted Davis, and University faculty involved in the research.~

The University of Minnesota began construction in February of a new facility to test structures for their resistance to earthquakes and other high-stress forces.  (See GSM News, Summer 2001)

The Multi-Axial Subassemblage Testing (MAST) system was funded by the National Science Foundation through a four-year, $6.5 million grant to the university’s civil engineering department. Dr. Catherine French, who conducted a tour of the university’s existing testing facilities for GSM members last year, is the principal investigator on the project, along with Dr. Arturo Schultz.

The U of M’s MAST facility will become part of the nationwide Network for Earthquake Engineering Simulation (NEES), a network of 12 similar facilities nationwide conducting research on structural components of buildings. The facilities will be linked by the internet, allowing researchers from around the world to obtain data from, or participate in, experiments at any other NEES facility. The goal of the NEES project is to allow earthquake engineering researchers to work on integrated physical models, databases and model-based simulation rather than isolated physical experiments.

The MAST testing system incorporates 10 hydraulic cylinders capable of delivering up to 880,000 pounds of force in both horizontal directions while simultaneously delivering 1.3 million pounds of force vertically. No other testing facility can so closely simulate earthquake forces, according to French and Schultz.

                                                                                                                                                                                ~Tom Smalec

 

 

GROUNDWATER – Carver County, Minnesota, Part I in a Series
by Bruce Goetteman

 

 

 Confining rock layer

At the time this picture was taken, bedrock was a limiting factor when dipping a well. This 1920s photograph gives literal meaning to the term “confining rock layer”. Bedrock type and depth determined, in large part, whether or not a parcel of land was suitable for a homestead. The setting for this photograph is in Stearns County, Minnesota.

Closer to home, in Carver County, Minnesota, I have had the privilege of contributing to the development of a groundwater protection plan for the County. This experience has allowed me to gain insight and thus be able to provide a general overview of the hydrogeologic structure of Carver County.

The settlement of Carver County in the 1840s & 50s created a demand for water supply which was safer than that found in the rivers and lakes.  Wells were needed.  While other technology existed, the typical well was constructed by hand digging, and lining the well with brick, stone, or wood.  These wells utilized the water table aquifer.  Consequently, they were highly susceptible to contamination from any number of sources

 

As the supply of water in the water table aquifer was depleted, became contaminated, or was not sufficient to meet demand, deeper wells were constructed using technologies such as cable tool, jetting, hollow rod, and other techniques.  These well designs were less likely to become contaminated than the previously dug wells.  In addition to deeper wells, the newer technologies permitted a deeper understanding of the geologic structure of the County.

Carver County is part of a geologic structure called the Hollandale Embayment, which formed as a result of erosion, sedimentation, and the rise and fall of ancient seas. In brief, these actions resulted in a sedimentary deposition of rock over 1,000 feet deep that covers older sedimentary and igneous rocks. The significance of this formation for groundwater planning is that, along with the glacial drift, it makes up the groundwater system in Carver County.

The uppermost layer in the system is the glacial drift, which covers the entire county at depths from 100 to over 500 feet.  Repeated advances and declines of glaciers over the last two million years deposited drift. The last of these deposits is likely from the Wadena and Des Moines lobe advances that occurred during the Wisconsin glaciation 75,000 to 12,000 years ago.  Glacial drift consists of two types of sediment: till and outwash.

Till is unconsolidated (mixed) material consisting of varying portions of clay, silt, sand, gravel, and boulders. The composition of the mixture can affect the transmission of the groundwater through the system. Till that tends to be clayey will transmit water more slowly than till with high percentages of sand and gravel. In some areas of the county, very heavy deposits of clay occur which severely limit the transmissivity of water.  While till in an area may be clayey, there will typically be sand and gravel lenses which can greatly affect the flow of water through the drift layer making localized flow of groundwater extremely variable.

Outwash is sand and gravel material that has been deposited by a stream or river.  It is highly permeable and will transmit water at a high rate. Areas closer to the Minnesota River show large amounts of outwash deposited from the glacial River Warren. The development where I reside is situated on one such area.

Carver County has more than 4200 homes served by on-site wells.  Approximately 3000 of these wells have been constructed since 1975, when the Well Log program was initiated. Examination of the Minnesota Geological Survey and local databases indicated that over 30 percent of the wells are finished in drift. All of the residential wells in my neighborhood are in outwash.

Next time: Part II will explore the Bedrock Strata in Carver County and their relationship to groundwater.

 

 

 

Text of the Geological Marker which will be Located in Fillmore County, within Fountain City Park and adjacent to Highway 52.

 

GEOLOGY OF SINKHOLES

 

The surrounding area and much of southeastern Minnesota are karst landscapes.  Minnesota’s karst landscapes consist of limestone and dolostone bedrock that lies very close to the surface.  This carbonate bedrock is often riddled with features eroded by slightly acidic water: sinkholes, passageways, extensive underground water systems, and caves.

Rainwater becomes slightly acidic by absorbing carbon dioxide in the atmosphere, and if it seeps through the soil, by absorbing the carbon dioxide given off by plant roots, bacteria, and other organisms.  Over time, this water following bedrock joints, or fractures, dissolves the carbonate rock and gradually enlarges the passageways.  A system of underground drainage will develop that bypasses the surface drainage pattern.  Sinkholes are inlets to that system.

A sinkhole may begin to develop where joints in the bedrock intersect and the downward flow of water is more rapid.  Over time, a funnel-shaped cavity often forms in the rock.  Infiltrating surface water erodes the soil and moves it down the hole, thus forming a pronounced depression in the ground.  When erosion into the subsurface is slow, sinkhole formation is also a slow, gradual process.  When erosion is rapid, a sudden collapse of overlying sediment can occur.  Sinkholes sometimes collapse suddenly after heavy rains.  A sinkhole may become temporarily closed as newly collapsed sediment clogs the passageway.

In a karst landscape, water flowing into sinkholes bypasses the natural filtering action of a lengthy percolation through thick soil and sediment layers.  Once in the bedrock, water can move rapidly through a complex system of passageways at rates as high as several kilometers per day.  Using dye to color the water, scientists have shown that water entering this sinkhole emerges in about a day at the headwater springs of Trout Creek, about two kilometers northwest of here. 

In karst terrains, bedrock aquifers, a common source for drinking water, are susceptible to rapid contamination from activities on the surface of the land.  Likewise, water quality in spring-fed streams, which mark the end point of underground drainage in a karst landscape, may also be affected.

Erected by the Geological Society of Minnesota in partnership with the

Minnesota Department of Transportation and the Minnesota Geological Survey 

2002

*****

 

 

 

 

 

National Cave and Karst Research Institute

Caves and karst systems support fragile ecosystems, contain mineralogical resources, and are important water supply sources.  Improved knowledge of caves and karst systems leading to improved protection and management is important to ecosystem and public health and to sustainable economic development.  Several congressional acts have addressed the need for inventories of cave and karst resources and the need to have a scientific basis for cave and karst management.

 In October 1998, Congress passed the National Cave and Karst Research Institute Act that mandated the National Park Service to establish and operate the institute.  The act stipulated that the institute be located in the vicinity of Carlsbad Caverns National Park in New Mexico (but not inside park boundaries), and that the institute cannot spend federal funds without a match of private funds.

 The interim director for the National Cave and Karst Research Institute reported in July 2000 for a two-year period to move forward with National Park Service efforts to establish the institute by defining the purview and scope of operation, designing an organizational structure, forming partnerships, finding funding sources and a physical facility, and defining research needs.  The institute will pass through several phases before it fully reaches the capacity to sponsor a wide range of activities.  The fully operational phase should be attained by 2006, when the institute becomes a significant and recognized resource in cave and karst research, education, and support of cave and karst management.

 

SINKHOLE DYNAMICS

Geologists classify sinkholes based on their geometry and how they developed. Understanding sinkhole dynamics is critical to detecting and mitigating damages these karst features can cause. 

 Collapse sinkholes occur when the bridging material over a subsurface cavern cannot support the overlying material. The cover collapses into the cavern and a large, funnel-shaped depression forms. 

 Solution sinkholes result from increased groundwater flow into higher porosity zones within the rock, typically through fractures or joints within the rock. An increase of slightly acidic surface water into the subsurface continues the slow dissolution of the rock matrix, resulting in slow subsidence as surface materials fill the voids. 

 Alluvial sinkholes are older sinkholes that have been partially filled with marine, wetland or soil sediments. These features are common in Florida, where the water table is shallow, and typically appear as shallow lakes, cypress “domes” and wetlands. 

 Raveling sinkholes form when a thick overburden of sediment over a deep cavern calves into the void and pipes upward toward the surface. As the overlying material or “plug” erodes into the cavern, the void migrates upward until the cover can no longer be supported and then subsidence begins. 

 

 

 

 

FIELD TRIPS – 2002

 

May 18th            Hydrogeology of the Rochester and Surrounding Areas

                        *Leaders:  Tony Runkel and Robert Tipping, Minnesota Geological Survey

The Jordan Sandstone and Prairie du Chien Dolomite bedrock layers will be the focus of this one-day trip.  Stops will provide opportunities to examine exposures of these formations.  Discussion topics will include groundwater systems, surface water, karst terraines, etc.

 

June 15-16             Wisconsin South Shore Geology 

*Leader:  Tom Fitz, Northland College, Ashland, Wis.

                        This trip will begin in the Superior, Wis. area and work East from there.

                        Several Wisconsin State Parks will be visited.

 

July 27-28              Geologic Highlights of SW Minnesota 

*Leader:   Dale Setterholm, Minnesota Geological Survey

The participants in this field trip will examine Precambrian rocks of the Minnesota River valley, the Sioux Quartzite and catlinite (pipestone) beds, and glacial features.  Stops will include the Pipestone National Monument and the Jeffers Petroglyphs.

 

Sept 7-8               Minnesota North Shore Geology

                        *Leader:   Jim Miller, NRRI

The Gunflint Trail has a wonderful cross section of everything – gabbro, mid-continent rift, Mesabi iron formation, Copper-Nickel base of the Duluth complex, and more.  We will explore this area on the first day of the trip, beginning in Grand Marais, and will work our way down to Beaver Bay at the end of day 2

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