| Impressamergel Formation | |
|---|---|
| Stratigraphic range: | |
| Type | Formation |
| Underlies | Wohlgeschichtete Kalk Formation |
| Overlies | Ornatenton Formation |
| Thickness | 25 to 125 metres |
| Lithology | |
| Primary | Limestone |
| Location | |
| Country | Germany |
The Impressamergel Formation is a geologic formation in Germany. It preserves fossils dating back to the Jurassic period.
The term was proposed by Gert Bloos, Gerd Dietl and Günter Schweigert in 2005 for a lithostratigraphic rock formation. The name goes back to the term Impressakalke introduced by Friedrich August Quenstedt in 1857. The name is derived from the brachiopod Terebratula impressa (today Aulacothyris impressa ).
The Impressamergel formation includes dark gray to light gray limestones with some embedded limestone beds. The lower limit is relatively well defined by the change in color (from "brown" to "white" Jura). The upper limit is formed by the onset of the limestone of the Wohlgeschichtete Kalk Formation . It meshes with the Lochen Formation especially in the higher part and is increasingly replaced by this formation. In the Upper Rhine Valley, it is represented by Kandern Formation, Korallenkalk Formation and Nerineenkalk Formation . The distribution of the Impressamergel formation extends over the entire Swabian Alb to the Wutach area.
The Traverse Group is a geologic group in Michigan, Indiana and Ohio comprising middle Devonian limestones with calcareous shale components. Its marine fossils notably include Michigan's state stone, the Petoskey stone, among other corals and records of ancient marine life. A range of trilobites has also been found in the Traverse Group.
The Williamsport Sandstone is a sandstone geologic formation in West Virginia, Virginia, Pennsylvania, and Maryland. The formation includes the Cedar Creek Limestone member. Near Cumberland, Maryland it includes the Cedar Creek Limestone member. It preserves fossils dating back to the Silurian period.
The Maxville Limestone is a geologic formation in Ohio. It preserves fossils dating back to the Carboniferous period.
The Sugar Run Dolomite is a geologic formation in Illinois. It is a finely-bedded dolomite, preserving fossils dating back to the Silurian period. This formation is named for the Sugar Run stream in Joliet, along which it is well exposed. The dolomite is off-white/grey on freshly cut surfaces but over time oxidizes to a distinctive cream yellow color due to trace presence of iron. It is a member of the Niagaran series.
The Kinzers Formation is a geologic formation in Pennsylvania. It preserves fossils dating back to the Cambrian Period.
The Tomstown Dolomite or Tomstown Formation is a geologic formation in Maryland, Pennsylvania, Virginia and West Virginia. It preserves fossils dating to the Cambrian Period.
The Smackover Formation is a geologic formation that extends under parts of Arkansas, Louisiana, Texas, Alabama, Mississippi, and Florida. It preserves fossils dating back to the Jurassic period. The formation is a relic of an ancient sea that left an extensive, porous, and permeable limestone geologic unit.
The Lithograph City Formation is a geologic formation in Iowa, part of the Cedar Valley Group. It preserves fossils dating back to the Devonian period. The formation is composed of dolomite and limestone, with many fossils and vugs in the lower part, while the upper part contains few fossils.
The Del Rio Clay is a geologic formation in Texas. It preserves fossils dating back to the Cretaceous period.
The Edwards Group is a geologic group in Texas. It preserves fossils dating back to the Cretaceous period.
The Troublesome Formation is a geologic formation in Colorado. It preserves fossils dating back to the Neogene period. It consists of Pale shades of pink, tan, gray, green, and white interbedded siltstone and mudstone, less abundant arkosic sandstone and conglomerate, and sparse limestone and altered crystal-vitric ash and tuff; generally poorly consolidated. It includes atypical deposits containing abundant pink, granitic cobbles and boulders along the western parts of the outcrop in the west-central and southwestern parts of the Granby Quadrangle, Fossil mammals from three sites indicate a late Oligocene age.
The Langston Formation is a geologic formation in Idaho and Utah. It preserves fossils dating back to the Cambrian period. The formation is composed of bluish-gray limestone, weathering to a buff color, often with rounded edges.
The Notch Peak Formation is a geologic formation in Utah. It preserves fossils dating back to the Cambrian period.
The Colton Formation is a geologic formation in Utah. Its age is based on its position between the Upper Cretaceous-Paleocene North Horn Formation and overlying Green River Formation.
The Virgin Formation is a geologic formation in Utah. It preserves fossils dating back to the Triassic period.
The Cobourg Formation is a geologic formation in Ontario. It preserves fossils dating back to the Ordovician period. Technically the formation extends into New York State with Canadian section called Lindsay Formation. The formation was named by Raymond (1921). The Cobourg formation was estimated to have a total thickness of about 70 m.
The Assistance Formation is a geologic formation located on Devon Island and Ellesmere Island in Nunavut. It preserves fossils dating back to the Permian period. The formation rides along the southeastern edges of the Sverdrup Basin, as well as on Melville Island and Grinnell Peninsula.
The Agua Nueva Formation is a geologic formation in Mexico. It preserves fossils dating back to the upper part of the Cenomanian stage of the Cretaceous period. It consists "predominantly of alternating fossiliferous, organic matter-rich, laminated, dark gray limestone and non-laminated, organic matter-poor limestone in decimeter-thick beds with occasional centimetric beds of brown shale that show no apparent internal structures." The formation is noted for its qualities as a Konservat-Lagerstätte, with notable finds including the plesiosaur Mauriciosaurus, the mosasaur Yaguarasaurus and sharks Ptychodus and Aquilolamna.
The Georgetown Formation is a geologic formation in Mexico and the United States. It preserves fossils dating back to the Cretaceous period.
The Staffin Bay Formation is a geologic formation in Scotland. It preserves fossils dating back to the Callovian of the Middle Jurassic. It consists of two members, the lower Upper Ostrea Member, which consists of dark grey, fissile mudstone with a shelly limestone bed, and laminated and rippled sandstones. While the upper Belemnite Sands Member consists of medium-grained calcareous sandstones and siltstones
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