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Indiana Geological Survey Summary of Indiana Geology

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Indiana Geological Survey Summary of Indiana Geology Map illustrating plate boundaries and tectonic movement [1] Igneous Rocks Volcanic eruption (Iceland) Devils Tower Wyoming Metamorphic Rocks Kink banding in metamorphic rock Diagram showing major depositional basins for sediment accumulation. Sedimentary Rocks Periods Cambrian Precambrian Pre-erosional surface Periods Pennsylvanian Mississippian Devonian Silurian Ordovician Cambrian Precambrian Periods Pennsylvanian Mississippian Devonian Silurian Ordovician Cambrian Precambrian Million years Recent Periods 295 Pennsylvanian 325 Mississippian 355 Devonian 410 Silurian 435 Ordovician 540 Cambrian 1.8 billion Precambrian Yrs. ago Periods Pennsylvanian Mississippian Devonian Silurian Ordovician Cambrian Precambrian Jointed limestone bedrock Joints enlarged by solution Sinkholes of the Mitchell Plain Stream in cave passage Tight cave passage Sediment sorting by running water Shale bedrock (shale weathers in part by slaking) Ripple marks and cross-bedding in sand dune complex Sandstone bedrock with preserved cross-bedding Evaporite deposits (white deposits) Geologic Time Unconsolidated Deposits [2] The Ice Age Periods Quaternary Pennsylvanian Mississippian Devonian Silurian Ordovician Cambrian Precambrian Glacial till (five events represented in this exposure) Striated Boulder (striae were cut by more recent ice advance) Braided outwash plain (Red Glacier, Alaska) Valley train outwash sand and gravel Glacial Outwash and Related Deposits Explanation Alluvium Outwash Outwash fan Pitted outwash deposits Pinhook Bog (LaPorte County, Indiana) Pitcher plant (Pinhook Bog, LaPorte Co., Indiana) Map of northwestern Indiana, Lake Rim district [3] Quaternary Deposits EXPLANATION a,b Wisconsin glacial c,d till e Pre-Wisconsin till f Wind-blown silt g Glacial lakes h Sand and gravel of glacial river origin [4] Physiographic Regions [5] Bedrock Geologic Map EXPLANATION Pennsylvanian Mississippian Mississippian- Devonian Devonian Silurian Ordovician [6] View of Knobstone Escarpment from Weedpatch Hill (Brown County State Park) Small bedrock stream valley filled with glacial till Tipton Till Plain For Further Information Please Contact: Indiana Geological and Water Survey 611 North Walnut Grove Bloomington, IN 47405 IGWS.Indiana.edu E-mail: [email protected] 812-855-7636 References [1] Composite derived from various sources. [2] Derived and modified from Gray, H.H, 1983, Map of Indiana showing thickness of unconsolidated deposits: Indiana Geological Survey, Miscellaneous Map 37. [3] Derived and modified from Schneider, A.F. and Keller, S.J., 1970, Geologic map of the 1o X 2o Chicago quadrangle, Indiana, Illinois, and Michigan, showing bedrock and unconsolidated deposits: Indiana Geological Survey, Regional Geologic Map No. 4 (Chicago Sheet). [4] Derived from Gray, H.H., 1989, Quaternary geologic map of Indiana: Indiana Geological Survey, Miscellaneous Map 49. [5] From Gray, 2001, Map of Indiana showing physiographic divisions: Indiana Geological Survey, Miscellaneous Map 69. [6] Modified from Indiana Geological Survey, 1990, Map of Indiana showing bedrock geology: Indiana Geological Survey, Miscellaneous Map 50..
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