12-16 October 2011 2011 Four Day Field Trip Editors: Gary Motz and Julia Wise With contributions from: Dr. Carlton Brett, Dr. Thomas Lowell, and Paul Stefanik 2011 University of Cincinnati Four Day Field Trip following the Annual Meeting of the Geological Society of America Field trip coordinators: Gary Motz and Julia Wise With contributions from: Dr. Carlton Brett, Dr. Thomas Lowell, and Paul Stefanik ROAD LOG See a digital copy of this road log at http://g.co/maps/whzq6 WEDNESDAY 2pm Carl’s Ordovician outcrop in Minneapolis city limits 5pm Drive to Interstate State Park, MN THURSDAY 9am Canoeing along the St. Croix River 1pm Drive to Mirror Lake State Park, WI FRIDAY 9am Structure of Ableman’s Gorge, WI 10:30am Structure of Van Hise Rock, Rock Springs, WI 12pm Glacial geomorphology of Devils Lake State Park, WI 5pm Camp at Mirror Lake State Park, WI SATURDAY 9am Wisconsin Dells, WI 12pm Drive to Kankakee State Park, IL 1pm Mazon Creek Paleontology, Morris, IL SUNDAY 9am Mazon Creek Paleontology, Morris, IL 12pm Drive to Cincinnati, OH CAMP MENU WEDNESDAY THURSDAY FRIDAY SATURDAY SUNDAY Bagels/Oatmeal/Fruit Bagels/Oatmeal/Fruit Bagels/Oatmeal/Fruit Bagels/Oatmeal/Fruit Sandwiches (PBJ, cold Sandwiches (PBJ, cold Sandwiches (PBJ, cold Sandwiches (PBJ, cuts, cheese) cuts, cheese) cuts, cheese) cold cuts, cheese) Spaghetti dinner Hot dogs/hamburgers, Shepherd’s pies (ground Taco night (hard and soft with salad veggie burgers beef/tofu, potatoes, taco shells with ground (crumbled Italian S’mores mixed vegetables, beef, tomatoes, sour sausage or TVP) cheese, fresh onion) cream, cheese, etc.) There will be a few snack items in camp, but if you’d like your own chips, drinks, etc. please plan to stock up either prior to the trip or at one of our gas station stops. Additionally, there will be ample vegetarian options for your enjoyment. Thanks! Campground Information Suggested Packing List Interstate State Park Cup/bowl/plate/utensils (please bring your own!!) 307 Milltown Road Swimsuit/clothes that might get wet (if canoeing) Taylors Falls, MN 55084 Towel 651‐465‐5711 Headlamp/flashlight Site: WP Tent Site Type: Group Tents (non‐electric) Loop: Group Sites EP & WP Sleeping pad/bag Arrival Date: Wed Oct 12 2011 Pocket knife Departure Date: Thu Oct 13 2011 Raingear/umbrella Hat/gloves Mirror Lake State Park Water bottle E10320 Fern Dell Road Baraboo, Wisconsin 53913 Notebook/pencils 608‐254‐2333 Clipboard Site: 304 iPod/iPad/Nook (it’s a long drive) Site Type: Group Tents (non‐electric) Camera Loop: Group Spare batteries Arrival Date: Thu Oct 13 2011 Departure Date: Sat Oct 15 2011 Hand lens Rock hammer Kankakee River State Park Hat/sunglasses 5314 West Rt. 102 Jeans Bourbonnais, IL 60914 Hiking boots 815‐933‐1383 T-shirts/Long sleeved shirts Site: Group Camp 001 Site Type: Group Tents (non‐electric) Fleece/sweatshirt (it will get cold at night) Loop: Davis Creek GSA attire Arrival Date: Sat Oct 15 2011 Extra space in luggage for fossils/rocks Departure Date: Sun Oct 16 2011 Camp chair General History/Geology INTERSTATE PARK Interstate Park and Taylor Falls illustrate the geologic history of our continent from rifting remains of the Precambrian craton to recent ice age structures. In the Precambrian the North American Craton began to separate. The continent ripped apart nearly severing the southeastern portion of North America and creating an oceanic basin (now the basin occupied by Lake Superior). The rifting, caused by a hotspot, domed, cracked, stretched, and thinned the earth’s crust creating allowing basalt to reach the surface of the continent. This resulted in repeating, massive, and rapid basalt flows. Over 2,000,000 km3 of basalt, nearly four miles thick, was emplaced within 22 Ma. The basalt follows the rift stretching from Canada to Kansas. Interstate Park sits on one of these flows. Eventually compression of the crust from orogenies to the East closed and deactivated the rift. Sea levels rose and by 500 Ma Interstate park was a shallow sea replete with trilobites, brachiopods, and other common Ordovician life. Fossil remains can still be found in the area. 100,000 Ya water played another role in shaping the Interstate Park region. The Wisconsin Ice Sheet plowed over the area grinding the lava flows into conglomerates, creating hills, and gouging large valleys: the topography of the region. Perhaps the most prominent feature is the St. Croix River valley. Formed as the Grantsburg Sublobe’s moraine and blocked the flow of the St. Croix forcing it to migrate from the North to the East. As the sublobe melted back it formed Glacial Lake Duluth. Melt water streaming from this lake carved the St. Croix valley as we see it today. The most recent chapter of in Interstate Park’s geologic history comes 10,000 years ago with the breaking of an n ice sheet that had been keeping Lake Duluth in place. 10,000 years ago Glacial Lake Duluth over topped the ice dam. Water flooded into the valley so forcefully it carved The Dalles of the St. Croix and cut Taylor’s Falls straight into the Precambrian basalt. For an idea of the scale of this outburst fed river: stand at the campground‐‐you are standing at the bottom of the Glacial St. Croix river. Swirling eddies of this river carved the “World’s Deepest Potholes” into the basalt of the area. These potholes can be over 50 feet deep and 15 feet wide and there are over 100 of them in fewer than 20 acres. DEVIL’S LAKE and THE BARABOO HILLS The Baraboo hills form the Northern and Southern arms of large gentle syncline. These quartzites dating to 1.7 Gya are bisected by several more recent valleys—one of which houses Devil’s Lake—formed by glacial processes. The Baraboo quartzites are the metamorphic remains of an early Proterozoic orogeny. The Penokean Orogeny saturated the shallow passive continental margin that Wisconsin lay on with sand. Over the next 200 million years rippled sandstone formed and was metamorphosed into quartzite as the orogeny continued. (Later this orogeny would rift apart as the Mid‐continent Rift System and emplace the basalts seen at Taylor Falls and Interstate Park). In the quartzites of the hills, early ripples are still visible. In the north at Ableman’s Gorge several layers of Cambrian cobble sit uncomformably upon rippled Precambrian quartzite standing at a 90 degree dip. In the northern arm of the Baraboo hills sits Devil’s Lake displaying Proterozoic, Cambrian, and Ice age geology. During the maximum extent of the most recent ice age the Green Bay Lobe of the Laurentide Ice sheet created a large terminal moraine blocking one of the Baraboo hills’ bisecting valleys forming Devil’s Lake. This moraine rises 100 feet above the current lake level. Devil’s Lake is a stream fed lake with no river drainage from it. Glacial overflow indicators such as potholes and carved gorges can be seen throughout the park. Beyond this end moraine are outwash planes. It’s estimated that 20,000 years ago the Green Bay Glacial Lobe was nearly 1000 thick. To the northeast of Devil’s Lake the lobe dammed the Wisconsin River forming Glacial Lake Wisconsin. When the ice dam failed a large flood was released cutting through the sandstone bedrock creating the Wisconsin Dells and leaving behind Central Sand Plains. MAZON CREEK In the Pennsylvanian, the depositional setting of northern Illinois consisted of numerous shallow marine bays. Plants and animals lived in the swampy areas along the rivers and as they died they fell to the bottom of the bay where they were rapidly buried in a muddy fluvial substrate and preserved. Bacterial decomposition of the organic matter produced carbon dioxide in the sediments around the remains. The carbon dioxide combined with iron from the groundwater around the remains, entombing these fossils in siderite concretions. The combination of rapid burial and rapid formation of siderite resulted in excellent preservation of the diverse assemblage of animals and plants in the Carboniferous of Northern Illinois. The quality and diversity of fossils recovered in the Mazon Creek nodules makes these localities important worldwide. In most fossil deposits only the hard parts of organisms are preserved, whereas in this lagerstätte, frequent soft parts and organisms that are generally not well preserved are in abundance (fossil jellyfish abound at these localities). These factors give a good indication of Mazon Creek paleoenvironment and stratigraphy that provide scientists with an extraordinary view of biodiversity 300 million years ago. Many of the fossils reported from the Mazon Creek localities include many plants (club mosses, horsetails, ferns, and gingkos) and animals (Tully monsters, jellyfish, corals, anemones, hydroids, worms, crustaceans, centipedes, insects, snails, clams, squids, fish, and many more) some of which are found nowhere else in the world. Reference List Here is a list of articles posted on the Blackboard website for your perusal and general background information: Attig, J., M. Bricknell, E. Carson, L. Clayton, M. Johnson, D. Mickelson, and K. Syverson. 2011. Glaciation of Wisconsin. In J. Robertson, ed. Wisconsin Geological and Natural History Survey, Madison, Wisconsin. Attig, J., P. Hanson, J. Rawling, A. Young, and E. Carson. 2011. Optical ages indicate the southwestern margin of the Green Bay Lobe in Wisconsin, USA, was at its maximum extent until about 18,500 years ago. Geomorphology 130:384‐390. Baird, G. 1978. Lithology and fossil distribution, Francis Creek Shale in northeastern Illinois. In M. Nitecki, ed. Mazon Creek Fossils. Academic Press, New York. Baird, G., S. Sroka, C. Shabica, and T. Beard. 1985. Mazon Creek‐type fossil assemblages in the U.S.