The Emigrant Springs Formation (Also known as the Emigrant Springs Limestone) is a geologic formation in Nevada. It preserves fossils dating back to the Cambrian period.
| Emigrant Springs Formation | |
|---|---|
| Stratigraphic range: [1] | |
| Type | Formation |
| Sub-units | See: Members |
| Underlies | Dunderberg Formation |
| Overlies | Patterson Pass Shale |
| Lithology | |
| Primary | Calcisiltite |
| Other | Mudstone, Calcilutite, Calcarenite |
| Location | |
| Region | Nevada |
| Country | United States |
Geology
editThe Emigrant Springs Formation is predominately composed of various carbonate rocks, and is overlain by the Dunderberg Formation, whilst it is underlain by the Patterson Pass Shale. It also contains three members, which are as follows, in ascending stratigraphic order (lowest to highest):
Members
edit- Member A: This member is the thinnest, only getting up to 256 ft (78 m) thick, and is composed of medium-gray, thin to medium-bedded calcisiltite and calcilutite, with breccia's in the upper beds of the member.[1]
- Member B: This member is the thickest, getting up to 1,509 ft (460 m) thick, and is dominated by light-olive-gray, yellowish or pink calcisiltite, which contains silt-sized quartz grains. At the base of this member, there are also mudstones present, transitioning to medium-light-gray, thin to thick-bedded calcisiltite and calcilutite above.[1]
- Member C: This member can get up to 495 ft (151 m) thick, and is primarily composed of medium-gray oolitic calcarenite, calcilutite and calcisiltite.[1]
Paleobiota
editThe Emigrant Springs Formation contains a small number of trilobites,[1] and a collection of conodonts, and various molluscs.[2]
Color key
|
Notes Uncertain or tentative taxa are in small text; |
Arthropoda
edit| Arthropoda | |||||
|---|---|---|---|---|---|
| Genus | Species | Notes | Images | ||
| Coosina[1] |
|
Ptychoparid trilobite. | |||
| Blountia[1] |
|
Ptychoparid trilobite. | |||
| Crepicephalus[1] |
|
Ptychoparid trilobite. | |||
| Tricrepicephalus[1] |
|
Ptychoparid trilobite. | |||
| Pemphigaspis[1] |
|
Ptychoparid trilobite. | |||
| Elrathia[2] |
|
Ptychoparid trilobite. | |||
| Cedaria (?)[1] |
|
Ptychoparid trilobite. | |||
| Meteoraspis (?)[1] |
|
Ptychoparid trilobite. | |||
| Baltagnostus[2] |
|
Diplagnostid agnostid. | |||
| Hypagnostus[2] |
|
Diplagnostid agnostid. | |||
| Pseudagnostus[1] |
|
Agnostid trilobite. | |||
| Utagnostus[1] |
|
Agnostid trilobite. | |||
| Kymagnostus (?)[1] |
|
Agnostid trilobite. | |||
| Lejopyge[2][1] |
|
Ptychagnostid agnostid. | |||
| Ptychagnostus[2] |
|
Ptychagnostid agnostid. | |||
| Glaphyraspis[1] |
|
Trilobite. | |||
| Cheliacephalus[1] |
|
Trilobite. | |||
| Aphelaspis[1] |
|
Trilobite. | |||
Chordata
edit| Genus | Species | Notes | Images |
|---|---|---|---|
| Hertzina[2] |
|
Furnishinid paraconodont. | |
| Westergaardodina[2] |
|
Westergaardodinid paraconodont. | |
| Furnishina[2] |
|
Furnishinid paraconodont. | |
| Distacodus[2] |
|
Distacodontid conodont. | |
| Oneotodus[2] |
|
Protopanderodontid tenuis. | |
Lophotrochozoa
edit| Genus | Species | Notes | Images |
|---|---|---|---|
| Helcionella[2] |
|
Helcionellid mollusc. | |
| Scenella (?)[2] |
|
Scenellid mollusc. | |
| Canthylotreta[3] |
|
Acrotretid brachiopod. | |
| Lingulella[2] |
|
Obolid brachiopod. | |
| Livnarssonia[2] |
|
Brachiopod. | |
| Paterina[2] |
|
Brachiopod. | |
See also
editReferences
edit- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Kellogg, Harold E. (1963). "Paleozoic Stratigraphy of the Southern Egan Range, Nevada". Geological Society of America Bulletin. 74 (6): 685. doi:10.1130/0016-7606(1963)74[685:PSOTSE]2.0.CO;2.
- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Clark, David L.; Robison, Richard A. (1969). "Oldest Conodonts in North America". Journal of Paleontology. 43 (4): 1044–1046. ISSN 0022-3360.
- ↑ Streng, Michael; Holmer, Lars E. (January 2006). "New and poorly known acrotretid brachiopods (Class Lingulata) from the Cedaria-Crepicephalus zone (late Middle Cambrian) of the Great Basin, USA". Geobios. 39 (1): 125–154. doi:10.1016/j.geobios.2004.10.004.
- Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Archived from the original on 25 March 2022. Retrieved 8 July 2014.