Waukesha Dolomite

Last updated
Waukesha Dolomite
Stratigraphic range: Silurian
Type Formation
Location
Region Wisconsin
Country United States

The Waukesha Dolomite is a geologic formation in Wisconsin. It preserves fossils dating back to the Silurian period.

Wisconsin A north-central state of the United States of America

Wisconsin is a U.S. state located in the north-central United States, in the Midwest and Great Lakes regions. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin is the 23rd largest state by total area and the 20th most populous. The state capital is Madison, and its largest city is Milwaukee, which is located on the western shore of Lake Michigan. The state is divided into 72 counties.

The Silurian is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.8 million years ago (Mya), to the beginning of the Devonian Period, 419.2 Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by several million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out.

See also

Paleontology in Wisconsin

Paleontology in Wisconsin refers to paleontological research occurring within or conducted by people from the U.S. state of Wisconsin. Wisconsin has a relatively sparse fossil record. Fossils found in Wisconsin are generally very old, most ranging from 500 to 300 million years in age. During the early part of the Paleozoic era, Wisconsin was covered by a warm, shallow sea that would be home to creatures like brachiopods, bryozoans, cephalopods, corals, crinoids, and trilobites. During the Silurian, Wisconsin was home to massive reef system that formed one of the most biodiverse habitats in all of North America at the time. The interval spanning the Permian, Mesozoic, Paleogene and Neogene are missing from the local rock record. During the Ice Age the local climate became cold. Seals, walruses, and whales left behind fossil remains in the state near the Great Lakes. On land, hemlock and spruce trees formed forests inhabited by creatures like giant beavers, horses, and woolly mammoths. The first fossil reef systems ever scientifically documented in North America were discovered in the area around Milwaukee. The Silurian reefs of the Milwaukee area were also the first known fossil reefs from the Paleozoic era. Their associated fauna is one of the most diverse from the period ever documented in North America. The Ordovician to Silurian trilobite Calymene celebra is the Wisconsin state fossil.

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Mericoceras is an extinct nautiloid cephalopod that lived during the Late Devonian and possible as early as the Silurian.

<i>Pleurodictyum</i> genus of cnidarians

Pleurodictyum is an extinct genus of tabulate corals, characterized by polygonal corallites. Colonies commonly encrust hard substrates such as rocks, shells and carbonate hardgrounds.

Paleontology in Illinois

Paleontology in Illinois refers to paleontological research occurring within or conducted by people from the U.S. state of Illinois. Scientists have found that Illinois was covered by a sea during the Paleozoic Era. Over time this sea was inhabited by animals including brachiopods, clams, corals, crinoids, sea snails, sponges, and trilobites.

Paleontology in Minnesota

Paleontology in Minnesota refers to paleontological research occurring within or conducted by people from the U.S. state of Minnesota. The geologic record of Minnesota spans from Precambrian to recent with the exceptions of major gaps including the Silurian period, the interval from the Middle to Upper Devonian to the Cretaceous, and the Cenozoic. During the Precambrian, Minnesota was covered by an ocean where local bacteria ended up forming banded iron formations and stromatolites. During the early part of the Paleozoic era southern Minnesota was covered by a shallow tropical sea that would come to be home to creatures like brachiopods, bryozoans, massive cephalopods, corals, crinoids, graptolites, and trilobites. The sea withdrew from the state during the Silurian, but returned during the Devonian. However, the rest of the Paleozoic is missing from the local rock record. The Triassic is also missing from the local rock record and Jurassic deposits, while present, lack fossils. Another sea entered the state during the Cretaceous period, this one inhabited by creatures like ammonites and sawfish. Duckbilled dinosaurs roamed the land. The Cenozoic period of the ensuing Cenozoic era is also missing from the local rock record, but during the Ice Age evidence points to glacial activity in the state. Woolly mammoths, mastodons, and musk oxen inhabited Minnesota at the time. Local Native Americans interpreted such remains as the bones of the water monster Unktehi. They also told myths about thunder birds that may have been based on Ice Age bird fossils. By the early 19th century, the state's fossil had already attracted the attention of formally trained scientists. Early research included the Cretaceous plant discoveries made by Leo Lesquereux.

The Maquoketa Formation is a geologic formation in Illinois, Indiana. Iowa, Kansas, Minnesota, Missouri, and Wisconsin. It preserves mollusk, coral, brachiopod and graptolite fossils dating back to the Ordovician period.

The Racine Dolomite is a geologic formation in Illinois and Wisconsin. It preserves fossils dating back to the Silurian period.

The Dresbach Formation is a geologic formation in Wisconsin. It preserves fossils dating back to the Cambrian period.

The Franconia Formation is a geologic formation in Wisconsin. It preserves fossils dating back to the Cambrian period.

The Jordan Sandstone is a geologic formation in Wisconsin. It preserves fossils dating back to the Cambrian period.

The Trempealeau Formation is an Upper Cambrian geologic formation in Wisconsin. It contains graptolites.

The Lake Church Formation is a geologic formation in Wisconsin. It preserves fossils dating back to the Devonian period.

The Milwaukee Formation is a geologic formation in Wisconsin. It preserves fossils dating back to the Devonian period.

The Oneota Formation is a geologic formation in Wisconsin. It preserves fossils dating back to the Ordovician period.

The Fort Atkinson Formation is a geologic formation in Wisconsin. It preserves fossils dating back to the Ordovician period.

The Manistique Formation is a geologic formation in Wisconsin. It preserves fossils dating back to the Silurian period.

The Byron Formation is a geologic formation in Michigan and Wisconsin. It preserves fossils dating back to the Silurian period.

The Brandon Bridge Formation is a geologic formation in Wisconsin. It preserves fossils dating back to the Silurian period.

The Mayville Formation is a geologic formation in Wisconsin. It preserves fossils dating back to the Silurian period.

References