GEOLOGICAL SOCIETY OF IOWA

Last fall’s GSI field trip investigated the “Natural History of Wapsipinicon State Park, Jones County, Iowa,” but also included a stop at the Weber Stone Company’s dimension stone quarry at nearby Stone City. About 94 field trip participants began the field trip at the Weber Quarry, one of a series of quarries in and around Stone City that are among the oldest in Iowa. These quarries produced building stone for many structures in the area and still produce a variety of products under the general name Anamosa Stone (Anamosa Member of the Silurian Gower Formation). The trip began in light snowfall, the first that any of us could remember on a fall GSI field trip. The first stop was the underground mines, now used principally for stone splitting during winter conditions. From there, we traveled to the active open quarry area where we discussed the geology and mining techniques and examined the quarry. Upon leaving the quarry area, we drove past the stone splitting operation, where stone is split and broken to standard dimension sizes for retaining walls and other uses, and back to the quarry office area for a tour of the rock sawing building. In that facility we viewed a series of diamond saws and related equipment used to cut slabs and other specialty items from the stone. The largest saw had a 16 ft diameter and fully automated. Other equipment included large routers for stone carving, laths for turning stone columns, and rock polishing equipment. There were many beautiful examples of their product stockpiled around the facility. Many thanks to Weber Stone Company for allowing us access to their facility and providing staff for the tour.

After the quarry tour, the field trip caravanned into Anamosa past the Anamosa State Penitentiary, a beautiful example of construction with Anamosa Member dimension stone, then continued to Wapsipinicon State Park to examine various aspects of the natural history of the park, including the a look at park geology and exposures of the Silurian Scotch Grove Formation rocks with Brian Witzke (IGWS). Brian led tours of Ice and Horsethief caves and exposures near the park entrance and exit. Joe Artz from the Office of the State Archaeologist led a discussion of the Native American activity in the park and surrounding area and described past archaeological activities. John Pearson (DNR) discussed the parks trees, including the white pine plantation and the grassland areas. Darryl Howe (DNR) provided great background information on the animals of the park including a discussion of threatened or endangered clams in the adjacent Wapsipinicon River. Last but not least, we thank Wapsipinicon State Park manager Dennis Murphy for helping arrange the field trip and being on hand to discuss the park’s history and answer questions.

The 8^th annual Project Aware Volunteer River Cleanup will this year clean the East and West forks of the Nishnabotna Rivers in southwest Iowa during the week of July 10-17. Project Aware annually chooses a stretch of an Iowa river for a canoe-based daily clean-up of junk and debris and evenings of camping and entertainment. Interested people may participate for a day, the entire week, or any period of time between. For more information see www.iowaprojectaware.com.

Earthscope is a National Science Foundation sponsored project to explore the structure and evolution of the North American Continent. The project draws on the scientific community to conduct multidisciplinary research across the Earth sciences utilizing the freely accessible data from geophysical instruments that measure motions of the Earth's surface, record seismic waves, and recover rock samples from depths at which earthquakes originate. One of the major components of this program is the transportable array, a grouping of 400 portable, unmanned three-component broadband seismometers deployed on a uniform grid along a swath that runs from Canada to Mexico. Each year 200 stations are removed and moved east to a new swath. This procedure will systematically cover the entire U.S. between 2005 and 2013. Each USArray station includes the instrumentation necessary to continuously sense, record, and transmit ground motions from a wide range of seismic sources, including local and distant earthquakes, volcanic eruptions, and other natural and human-induced activities. Scientists will use the information recovered information to develop models for the structure of the lower crust and mantle under the U.S. Beginning this summer, 12 seismic stations will be installed in western Iowa, with 20 additional stations to be installed in the summer of 2011. Each station will continuously record for 2 years before it is removed and relocated. For more information on the Earthscope program see www.earthscope.org.

An earthquake monitoring seismometer station was installed near State Center in Marshall County in 2006. The station is a part of the US Geological Survey’s Advanced National Seismic System (ANSS) Backbone Network , designed to provide accurate and timely data and information products for seismic events, including their effects on buildings and structures, employing modern monitoring methods and technologies. Data from the station is transmitted to a central data repository, the USGS Albuquerque Seismological Laboratory, where it is processed and disseminated via the internet to scientist and interested citizens. Today, the ANSS Backbone consists of nearly 100 stations in the United States, many of them contributed by partner networks and organizations. Learn more about the State Center station on its ANSS website at http://earthquake.usgs.gov/monitoring/operations/station.php?network=US&station=SCIA. To view any seismic activity detected in the last 24 hours at the State Center station, visit this site; http://aslwww.cr.usgs.gov/Seismic_Data/telemetry_data/SCIA_24hr.html.

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!

2010 GSI OFFICERS AND DIRECTORS
	President:	Chad Heinzel	Board of Directors:
	President Elect.:	Thomas Marshall		Jim Caldwell (2008-2010)
	Secretary-Treasurer:	Chad Fields		Stephanie Tassier-Surine (2009-2011)
	Past President:	Ray Anderson		John Dawson (2010-2012)

GEOLOGICAL SOCIETY OF IOWA

Spring 2010 NEWSLETTER

INTERNET EDITION

GSI world wide web homepage: http://www.iowageology.org


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.