The Cincinnati Arch is a broad structural uplift between the Illinois Basin to the west, the Michigan Basin to the northwest, and the Appalachian Basin and Black Warrior Basin to the east and southeast. It existed as a positive topographic area during late Ordovician through the Devonian period which stretched from northern Alabama northeastward to the southeastern tip of Ontario . Fossils from the Ordovician are commonplace in the geologic formations which make up the Cincinnati Arch and are commonly studied along man made roadcuts . The Nashville Dome of Tennessee and the Jessamine Dome or Lexington Dome of central Kentucky make up the central portion of the arch. In the northern part, north of Cincinnati, Ohio , the Cincinnati Arch branches to form the Findlay and Kankakee arches. The Findlay plunges under Ontario and reappears as the Algonquin Arch further north.
18-657: The Kankakee Arch is a geologic arch with a northwest–southeast trending axis which connects the Cincinnati Arch to the southeast with the Wisconsin Dome to the northwest. It lies beneath northeastern Illinois , northern Indiana and southeastern Wisconsin . This structural ridge lies between the Illinois Basin to the southwest and the Michigan Basin to the northeast. The area of central Illinois began to depress by
36-503: A few grams to several hundred kilograms in mass, coal balls are formed when water containing carbonate permeates the cells of an organism. This type of fossilization yields information about plant life in the Upper Carboniferous Period (325 to 280 million years ago). This method involves the elements sulfur and iron . Organisms may become pyritized when they are in marine sediments saturated with iron sulfides. ( Pyrite
54-418: Is a process of fossilization of bones and tissues in which mineral deposits form internal casts of organisms. Carried by water, these minerals fill the spaces within organic tissue. Because of the nature of the casts, permineralization is particularly useful in studies of the internal structures of organisms, usually of plants. Permineralization, a type of fossilization, involves deposits of minerals within
72-555: Is a shift as ocean levels dramatically drop and the Cincinnati Arch comes above the water line; after this point there is little sedimentation . The Ordovician period contained many marine animals. These animals can be found fossilized in the layers of the Cincinnati Arch. The types of animals that appear in these formations are: bryozoans , gastropods , cephalopods , horn corals , brachiopods , crinoids , and trilobites . Different species of each family can be found throughout
90-472: Is iron sulfide.) As organic matter decays it releases sulfide which reacts with dissolved iron in the surrounding waters. Pyrite replaces carbonate shell material due to an undersaturation of carbonate in the surrounding waters. Some plants become pyritized when they are in a clay terrain, but to a lesser extent than in a marine environment. Some pyritized fossils include Precambrian microfossils, marine arthropods and plants. Permineralized fossils preserve
108-510: Is the Richmondian. The Richmondian contains: Bull Fork , Saluda , Whitewater , Drakes and parts of Grant Lake Limestone as well as Fernvale and Arnheim. Formations can be a part of only one stage or in multiple stages depending on how old they are. Formations can also be represented in multiple states depending on how far they reach. The Cincinnati Arch formed from ocean sediments deposited between 488 and 444 million years ago on
126-581: The Edenain , Maysvillian , and the Richmondian . The Edenian stage is the oldest stage of the three. The Edenian contains these formations: Kope , Clays Ferry , Garrard Siltstone , Catheys , Inman , Fairview , and Leipers Limestone . The Maysvillian is the second oldest stage containing these formations: Dillsboro , Kope , Bellevue , Fairview , Grant Lake Limestone , Ashlock , Calloway Creek , Leipers , Fernvale , and Arnheim . The most recent stage
144-465: The North American Continent . The geology is characterized by layers of shale interspersed with layers of fossiliferous limestone . Layers of shale are believed to have formed from sediment deposited by large hurricanes . Shale layers can represent as little as a single day of sediment deposition. Shale layers indicate times of low ocean levels when erosion brought out more sediment from
162-510: The differences between layers in a vertical column. Laws can vary state to state, but in most cases collecting or working at these sites is legal as long as the roadcut is not located on an interstate highway . Popular roadcuts in the Cincinnati Arch can be found in Ohio, Indiana, and Kentucky. The most prominent of these roadcuts is one located near Maysville, Kentucky , known as the " Maysville roadcut ." Permineralization Permineralization
180-473: The weathering of rocks releases silicate minerals and the silica makes its way into a body of still water. Eventually, the mineral-laden water permeates the pores and cells of some dead organism, where it becomes a gel . Over time, the gel will dehydrate , forming an opaline crystal structure that is an internal cast of the organism. This accounts for the detail found in permineralization. Silicification reveals information about what type of environment
198-569: The arch. Over the arch, the depth of the deposits diminish, thus layers 100 feet (30 m) northeast of the arch become only 10 feet (3.0 m) across the top of the arch. As in the Silurian Period, the Devonian Period (438 to 408 MYA) witnessed a renewal of the shallow seas after a short period when the area was above sea level. Deposition resumed with related, but significantly different dolomites and limestones both north and south of
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#1732851898167216-422: The cells of organisms. Water from the ground, lakes, or oceans seeps into the pores of organic tissue and forms a crystal cast with deposited minerals. Crystals begin to form in the porous cell walls. This process continues on the inner surface of the walls until the central cavity of the cell, the lumen , is completely filled. The cell walls themselves remain intact surrounding the crystals. In silicification ,
234-408: The continent into the sea. Fossiliferous limestone is made up of beds of previously organic matter that has undergone permineralization and fossilized forming large mats of calcite and aragonite rich rock. These layers represent periods of sediment starvation when sea levels were elevated and the impact of tropical storms was negligible. In the most recent formations such as White Water there
252-647: The late Ordovician . The Cincinnati Arch was developing across eastern Indiana during the late Ordovician . By the Early Silurian the seas northwest of the Cincinnati Arch began to become shallower. By the Early Mississippian , the Kankakee arch was above sea level. During the Silurian Period (420 to 405 MYA) a shallow sea spread across Indiana. This sea deposited limestones along the southwest slope of
270-560: The layers in the region, with different concentrations depending on the formation. A typical fossil that is common in many road-cuts around the arch is the extinct Isorthoceras albersi . The geologic layers that make up the Cincinnati Arch are most easily viewed at roadcuts . Roadcuts are common along highways throughout the arch's range and are often studied by geologists and paleontologists alike. Since roadcuts are typically made quite steep they allow scientists to view changes in prehistoric conditions through millions of years by studying
288-535: The organism was likely to have lived in. Most fossils that have been silicified are bacteria , algae , and other plant life. Silicification is the most common type of permineralization. Carbonate mineralization involves the formation of coal balls. Coal balls are the fossilizations of many different plants and their tissues. They often occur in the presence of seawater or acidic peat. Coal balls are calcareous permineralizations of peat by calcium and magnesium carbonates. Often spherical in shape and ranging from
306-447: The original cell structure, which can help scientists study an organism at the cellular level. These three-dimensional fossils create permanent molds of internal structures. The mineralization process helps prevent tissue compaction, distorting organs' actual size. A permineralized fossil will also reveal much about an organism's environment and the substances found in it since it preserves soft body parts. This helps researchers investigate
324-593: The shallow area of the arch. Cincinnati Arch Petroleum was first discovered in a relatively low part of the arch, between the Jessamine and Nashville domes, the Cumberland Saddle, in Cumberland County, Kentucky , in 1829. The saddle and adjoining areas have been significant producers since drilling for oil came to the region in the late 19th century. The Cincinnati Arch contains three distinct stages:
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