The Geological History of Northwest Ohio - Assignment Example

Name of writer appears here] [Course name appears here] [Professor’s name appears here] [Date appears here] Geological history of Northwest Ohio Introduction The Phanerozoic eon consists of three era and thirteen periods Palezoic era: Beginning with Cambrian, Ordovician, Silurian, Devonian, Carboniferous [Mississippian period and Pennsylvanian period] and Permian, Mesozoic era: Triassic, Jurassic and Cretaceous, Cenozoic era: Tertiary [Paleogene period and Neogene period] and ending with Quaternary. 570 Million To 500 Million years ago: Cambrian Period When the Cambrian period began the supercilious Precambrian mountains, formed by continental collision around a billion years ago were transformed into gentle landscapes by a series of serious erosions. The Cambrian climate was generally warm, wet and mild. At the end of the Precambrian and beginning of the Cambrian period, the Laurentian continental plate in North America started to get separated from the eastern continental plate Baltica in Northern Europe, and the Iapetus Ocean formed. Northwest Ohio at that time was on the stable position of the Laurentian continent. The basal Cambrian rock unit in most of Ohio is the Mt. Simon Sandstone, quartzose sandstone that is widespread across a multistate area. The Mt. Simon Sandstone ranges from 0 to nearly 400 feet in thickness. Cambrian time brings about with it the beginning of the animal life with hard shells and early ancestors of insects, crabs and spiders began to emerge. At the end of the Cambrian period the entire Ohio was covered by water. Trilobites one of the first animals to have complex skeletal systems capable of leaving fossilized remains, jellyfish, sponges, and brachiopods swam the vast seas covering most of the earth. Sandstone, deposited on the sea floor millions of years ago, formed as tiny sand grains were lithified with natural cement. In Ohio, Cambrian sandstone forms a deep, thick base, sometimes up to 135 feet thick. The terrestrial environment, so far as we know, was devoid of animals and probably plants except, perhaps, for algae and lichens. (Janssens, p. 197) 500 Million To 440 Million Years Ago: Ordovician Period Northwest Ohio was about 45 degrees clockwise from its present orientation. Ordovician period climate, even though, favorable for marine life, is considered to be severe ice age. Carbondioxide was almost 8 to 20 times more than their current value preventing an ice age and even the sea levels were high during this period but dropped radically to about 50 m before ice age. The tropical land that was about to become Ohio as I have mentioned before was covered by saltwater with marine life existing and evolving including the appearance of a large jawless vertebrate fish. 440 Million To 400 Million Years Ago: Silurian Period Northwest Ohio during Silurian period entered in long warm greenhouse time. However latitudinal variations in climate were rather similar to today, with glaciers occurring in the higher latitudes (over 65o). Regions of marked aridity occurred within 40o of the Silurian equator. Its murky waters filled with coral reefs, algae, jellyfish and crustaceans. The remains of these early sea creatures compressed to form a ring of dolomite and limestone around the present-day site of Lake Michigan and Lake Huron, and they met Lake Erie west of Sandusky before continuing to Niagara along the Ontario shore. Toward the end of the period, the climate became hot and dry. As the water evaporated, they left behind deposits salt deposits in northeast Ohio and gypsum in northwest Ohio. In Fairport Harbor and Cleveland, salt is mined from up to three miles out under the surface of Lake Erie. In Painesville, miners drill deep wells to dissolve salt with water. As the water is pumped to the surface, it evaporates, leaving behind salt. Witness both Silurian dolomite and limestone on the Lake Erie Islands. 400 Million To 345 Million Years Ago: Devonian Period The climate was warm and equable. The combination of sea and dry arid land continued throughout Devonian period but by the middle of the Devonian period Ohio was again covered by saltwater. This is known as the Age of the Fish, where some grew up to 25 feet long. Life invaded freshwater and land, creating insects, vascular plants, vertebrate animals, and ferns. Limestone and shale (created as sea-bottom muds compacted) are remnants of this age. The limestone and dolomite from Silurian and Devonian respectively make up the western basin of Lake Erie's ground, averaging less than 25 feet in depth. As the glaciers scraped and scooped their way across North America, they were able to dig deeper basins to the east because of the soft shale. 345 Million To 320 Million Years Ago: Carboniferous /Mississippian Period Climate was warm. Again the movement over dry and sea continued in this time as the tectonic plates started to move toward each other. Few corals could survive because the water did not provide them with the survival environment due to being murky. However, lush vegetation began to grow on land. Berea Sandstone was laid during this time, perhaps created from sands that washed into the area from Canadian streams. 320 Million To 280 Million Years Ago: Carboniferous/ Pennsylvanian Period The rise and fall of the seas continued. When dry, Ohio's lands grew an extensive forest in coastal swamps. This was a tropical time with lush green environment and ferns growing as long as the trees. The leaves and stems were covered with water as soon as the sea level rose. For million of years this was covered with sand and clay which even preserved oxygen. Compressed with the weight of the water and other sediments, the stems and plant materials formed coal deposits in Pennsylvania and southern Ohio. 280 Million To 225 Million Years Ago: Permian Period As the two super-continents collided, a giant continent appeared. Although we may never know for sure, this collision may have been the force that created the Cincinnati and Findlay arches. Once higher, these land elevations were worn down over the years through erosion. Due to this arch formation some rock layers bended towards east and the older ones were bended towards the west side. Much of the interior of Pangea was probably arid, with great seasonal fluctuations (wet and dry seasons), because of the lack of the moderating effect of nearby bodies of water. This drying tendency continued through to the late Permian, along with alternating warming and cooling periods. Pelee, Middle and Kelleys Island are composed of the younger Devonian limestone, whereas the East Sister and Hen islands, along with North, Middle and South Bass islands, are composed of the older Silurian dolomite. As South Bass Island tilted during the upheaval of the Cincinnati Arch, the rocks weakened and gaps appeared. Water flowed through the gaps, causing the mineral anhydrite to expand. The expanding anhydrite changed to gypsum which pushed the limestone apart. The gypsum was then dissolved by moving groundwater and holes were left in the rock. These holes are the caves. Perry's Cave and Crystal Cave, both on South Bass Island, is the only two island caves open to the public. 225 Million To 135 Million Years Ago: Triassic and Jurassic Periods The rocks of the Northwest Ohio has no literate stories of the time known as “The Age of the Reptiles” the Mesozoic Era left little traces in the area surrounding Lake Erie. We don’t know as such anything about this age but the supercontinent of Pangea began to tear apart and Laurentia moved towards its present location in north. 135 Million To 65 Million Years Ago: Cretacious Period New species emerged; species that could adapt to this new environment. Tall beech and maple trees arrived, and deciduous forests began to appear. Birds, mammals and flowering plants appeared as the planet witnessed a warming period. North American was still joined on the east with Greenland and Europe, and on the west with Asia. This permitted animals and plant species to pass freely, and it's why similar plants and animals can be found between these continents. 65 Million To 2.5 Million Years Ago: Tertiary Period divided into Paleogene period and Neogene period An ancient river system drained much of the eastern and central United States. With its headwaters in North Carolina, the Teays River system flowed north across Virginia, West Virginia and Ohio. It branched off and eventually connected with the Erigan River. This east-flowing river had its center in what is now Lake Erie and flowed into the ancient St. Lawrence River. This ancient water system played an important role in the creation of Lake Erie. Although the river was dry by the time glaciers came to town, a long, wide basin remained. As glaciers moved across the land, this low-lying basin created the palette on which the ice could carve Lake Erie. 2.5 Million Years ago till today: Quaternary Period Known as the "Age of the Mammals," The Cenozoic Era has witnessed many changes to its physical and animal world. In fact, we are still in the Cenozoic Era today, and our world continues to evolve. Choices we make contribute to these ecological and biological changes. Our modern-day Ice Age begins during this time, and it left behind the shape of the land we see today. Read More