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     The Geological Society of Iowa will combine its Spring 2010 field trip with the Annual Meeting of the Iowa Academy of Science on April 17, 2010, at Graceland University, Lamoni, Iowa.  The field trip will provide an opportunity to learn about “The Pennsylvanian of South-Central Iowa”, with visits to the Decatur Quarry, 7 miles northeast of Lamoni, and the Thayer Quarry, southwest of Thayer, Union County (see map Figure 1 below).  The field trip will be led by Iowa Geological and Water Survey geologists Brian Witzke, Tom Marshall, and Charles Monson with assistance from University of Iowa professor Phil Heckel.

Field trip participants will be able to observe limestones, shales, and mudstones, Upper Pennsylvanian Series, Missourian Stage, from Bronson Group (above Pleasanton Formation) to the Kansas City Group (top of Dewey Formation).  These strata were deposited in cycles of marine transgression and regression over the landscape as glaciers in the Southern Hemisphere built up and melted back.  The Bethany Falls, Winterset, Westerville, and Cement City are the major limestones of interest, and the Galesburg, Stark, Fontana, Wea, and Quivira are the major shales of interest.  Participants will learn how geologists tell these units apart, which of the limestones are economic, and what makes them so.  Brian Witzke and Thomas Marshall will talk about the general stratigraphy of the area, and Charles Monson will discuss the fossils found in these quarries.  Participants can collect fossils that interest them as well as small samples of shale and limestone.  Phil Heckel will share his vast wealth of Pennsylvanian  knowledge, and Greg Schildberg, quarry owner and operator, may be along to discuss quarrying the Pennsylvanian.  Overall, this trip provides a good look into stratigraphy of a part of the state not often visited on GSI field trips.

Field Trip participants are asked to meet at in the West Event Parking Lot on the southwest corner of the campus of Graceland University in Lamoni (see map Fig. 2 below) at 12:30 pm on Saturday April 17, 2010.  We will travel by personal car caravan to the Decatur Quarry then the Thayer Quarry.  Participants are asked to bring hard hats if they have them (GSI will have some for those who need them), eye protection (safety glasses, regular glasses, or sun glasses) and closed-toe shoes (preferably leather boots).  Please do not wear sandals.  Rock collecting will be allowed and encouraged!

Figure 1.  Location of the GSI Spring 2010 field trip.  The box locates Lamoni and Graceland University, field trip departure point and the stars identify quarries to be visited.

Figure 2.  Map of the Graceland University Campus.  Star identifies the West Events Parking Lot where participants in the Spring 2010 GIS field trip will meet prior to departure at 12:30 pm.

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