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Natural History of Cleveland UST 259. Lecture 2 Geology – Glaciacian – Landform Regions. Natural History of Cleveland. GEOLOGY. Ohio Bedrock. Bedrock foundation of Ohio landform Composed of different kinds of rock Highly susceptible to erosive forces, but form basis of our soils
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Natural History of ClevelandUST 259 Lecture 2 Geology – Glaciacian – Landform Regions
Natural History of Cleveland GEOLOGY
Ohio Bedrock • Bedrock foundation of Ohio landform • Composed of different kinds of rock • Highly susceptible to erosive forces, but form basis of our soils • 11 different rocks that comprise our bedrock in Ohio
Ohio Bedrock • Conglomerate • Sandstone • Shale • Siltstone • Limestone • Dolomite • Chert • Clay • Gypsum • Coal • Salt
Ohio Geology • 3 categories of rocks in Ohio: • Igneous – Igneous rock is formed through the cooling and solidification of magma or lava. • Sedimentary – Sedimentary rock is a type of rock that is formed by sedimentation of material at the Earth's surface and within bodies of water. • Metamorphic – Metamorphic rock is the transformation of an existing rock type, in a process called metamorphism, which means "change in form". How rocks form animation Images of 3 types of rock
Ohio Bedrock • All Ohio bedrock is stratified • Occurs in layers • Formed by sediment deposits left by ancient seas, swamps, and marsh land • Forms what we call Sedimentary Rock
Ohio Geology • Fossil formation • Plant and animal decomposition • Became embedded in sediment layers – water, dry out, water, dry out… • Fossils show what plants and animals lived during different time periods, as well as what the land form was like (under sea?)
Ohio’s Geologic Timetable Broken up into Era’s and Periods
Ohio’s Geologic Timetable • Based on Era’s and Period’s • Track geologic activity over long period of time • Provide “picture” of landform conditions – again, under water, dry out…
Precambrian Era • All geologic time prior to Paleozoic Era • 4.5 billion years ago to 544 million years ago • First Invertebrates Precambrian
Cambrian Period • Start of Paleozoic Era • Marine seas • Limestone sediments Cambrian
Ordovician Period • Warm, shallow seas • Bryozoans • First land plants image of bryozoan Ordovician
Silurian Period • Cleveland area covered by Silurian Sea during most of this period • Return of warm, shallow seas • Limestone, dolomite • Halite Silurian
Devonian Period • Dry early, then seas again • Columbus limestone formation • Ohio shale on top of limestone Devonian
Devonian Period (continued) • Ohio Shale is very dominant in NE Ohio • Evident in Rocky River • Formed by small grains of mineral (clay / mud) Devonian
Mississippian Period • Period saw more sands and silts • Led to formation of sandstone • Black shale (Bedford shale) • Berea sandstone Mississippian
Mississippian Period (continued) • Amherst, Ohio – home to one of the largest sandstone quarries • One of the thickest layers of sandstone formation at 200’ thick
Pennsylvanian Period • Again Ohio is covered by sea, but more coastal swamps • Two important minerals formed during this period • Sand and clay buried and compressed marsh vegetation to form coal • Flint also formed during this period out of limestone–Ohio’s State Mineral • Coal is Ohio’s most important mineral Pennsylvanian
Permian Period • Said to be last period for Ohio rock formation • Sea covered but more coastal plain swamp • However… Permian
Mesozoic & Cenozoic Eras • No rock formation? • No fossils • Why? – different theories • Geologists theorize that rock formed but was likely removed by erosion Mesozoic & Cenozoic Eras
Geologic Map & Cross Section of Ohio showing closest rock to surface:
O.K., so now we have all of this rock… Now what?
Natural History of Cleveland Glaciacian
Glaciacian • 4 classical known glacial periods • Nebraskan • Kansan • Illinoian • Wisconsinan
Glaciacian • 56 of Ohio’s 88 Counties at one point were covered in ice • 1,000 to 8,000 feet thick • Over a period of million’s of years Continental glacier images
Glaciacian • Last glacial activity was about 25,400 years ago • Wisconsinan • End moraine • Ground moraine & • esker
Estimated to be 8,000 feet thick over Cleveland End moraines – Geologists measure ice movement by studying till left as glacier receded Plants & Animals – Impacted by ice & temperature, moved from needle bearing trees (spruce-fir-pine) to current broad leaf species (oak-maple-beech). Animals better adapted, demise more related to over hunting. Ice Over Ohio
Impact of Glaciers • Picture Ohio flat from layers of build-up from ancient seas • 60 million years of erosion – stream flows, wind, freeze & thaw – then eroded surface into rolling hills, steep hills similar to SE Ohio • Last ice age came through and shaped current landscape - Polished rock surfaces, glacial grooves
Interesting Phenomenon • Kames & Eskers – deposits left by glaciers forming various landscape features • Valleys – may appear like valley formed by glacier movement, but some are glacial till • Cuyahoga – 500’ old valley under river • Till = glacier dirt
Interesting Phenomenon • Are we done? • Geologists predict that we could se another Ice Age that could possibly include Ohio • Not in our lifetime, but what happened to Global Warming?
So, we had this rock, it got eroded and shaped by ice… Now what?
Natural History of Cleveland Landform Regions
Today’s Landscape • NevinFenneman – U of C Geology Professor • Described 5 Physiographic Regions that exist in Ohio • Regions: • Lake Plains • Till Plains • Bluegrass • UnglaciatedAppalacian Plateau • Glaciated Appalacian Plateau
Today’s Landscape • Lake Plains – Primarily NW Ohio but runs along entire shoreline • Includes Cleveland • Very flat, fertile but poorly drained soils • Great Black Swamp • Areas of sand dunes / bars • Number of roads built on • the ridges. Lake Plains
Today’s Landscape • Till Plains – Western part of the State • Less flat, better drainage • Rich farmland • Hills composed of boulders and soil left from glaciers • Southwest of Cincinnati- Clay soils are hard and poorly drained • “Crawfish Land” due to conditions ripe for crawfish burrows. Crawfish (or crayfish) image Crawfish chimney Till Plains
Today’s Landscape • Bluegrass – Small area in Southern Ohio • Famous area for Serpent Mound, known for a possible meteor explosion and well known Indian burial place Serpent mound Bluegrass or Lexington Plain
Today’s Landscape • Unglaciated Appalachian Plateau – Southeast portion of the State • Primarily sandstone outcrop • Area of fertile soils • Undisturbed vegetation (at least from glaciers) Unglaciated Appalachian Plateau
Today’s Landscape • Glaciated Appalachian Plateau – Just South of Cleveland • Less hilly • More fertile agricultural area then the unglaciated region. Glaciated Appalachian Plateau
Today’s Landscape • Ohio blessed with abundant fresh water – drains to Lake Erie to the North and Ohio River to the South • Over 6,000 streams in 18 watersheds • Third of water lost to evapotranspiration, third to runoff, and third that eventually infiltrates and re-charges groundwater • Western Ohio stores more due to limestone & permeable glacial outwash storage River drainage and watersheds
Today’s Landscape • Watershed • Land area drainage • Rain & snow melt • “Bowl”
Today’s Landscape • In 1970, Ohio ranked 5th in the nation in water use – consumption by residents, industry, & agriculture • Productive drilling (ground H2O), but need to be aware of valuable resource
Today’s Field Visit • Rocky River Nature Center • Field Trip – Focus on Geology / Some Glacial Impacts • Meet at 1:00 pm @ Nature Center