Emigrant Springs Formation
Geologic formation in Nevada, United States
From Wikipedia, the free encyclopedia
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
The Emigrant Springs Formation contains three members, which are as follows, in ascending age:
Members
- 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
The 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
| 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
| 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
| 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. | |