The Reed Dolomite is an Ediacaran aged geologic formation in California, outcropping in the White and Inyo Mountains, as well as Esmeralda County, Nevada, and is fossiliferous in nature.
| Reed Dolomite | |
|---|---|
| Stratigraphic range: [1] | |
.jpg) Cymopterus cinerarius, growing on substrate within the Reed Dolomite | |
| Type | Geological Formation |
| Sub-units | Lower, Hines Tongue, and Upper Members |
| Underlies | Deep Spring Formation |
| Overlies | Wyman Formation |
| Thickness | 0–1,600 ft (0–488 m)[1] |
| Lithology | |
| Primary | Dolomite |
| Other | Quartzite, Sandstone |
| Location | |
| Region | California, Nevada |
| Country | United States |
Geology
editThe Reed Dolomite, as its name suggests, is mainly composed of medium-gray, yellowish-gray, and pale-yellowish-brown medium to coarse-crystalline dolomite. Within these dolomites, oolites, pisolites and irregular pellets, which all may be algal in origin.[1]
Members
editThe Reed Dolomite contains three members, which are as follows, in stratigraphic order (lowest to highest):
- Lower Member: This member is primarily composed of coarse-crystalline pink dolostone, which is cross-bedded with oolthic horizons and minor domal stromatolite horizons, and was most likely deposited in a sub-tidal to inter-tidal marine environment.[2]
- Hines Tongue: The Hines Tongue forms the middle member of the formation, as is a wedge of clastic material, which can get up to 800 ft (240 m). It contains a number of minerals, but is primarily composed of yellowish-gray or very-pale-orange evenly laminated quartzite and calcareous sandstone, some of which is very fine to fine, and fine to medium grained. There is also medium-gray to pale-yellowish-brown dolomite, limestone, sandy dolomite, and sandy limestone within the wedge. It is also inter-stratified with quartzite and calcareous sandstone. There are also small yellowish-gray to pale-yellowish-brown siltstone,[1] and may have been deposited below a normal wave base, but above the storm base. It also contains a number of trace fossils throughout.[2]
- Upper Member: This member is predominately composed of massive dolostones, with minor karstification at the contact point with the overlying Deep Spring Formation. It is also known to contain packstones of Cloudina.[2]
Paleobiota
editThe Reed Dolomite contains a number of algal structures, as well as the mollusc like fossils Wyattia, and ichnogenera such as the Skolithos burrows.[1][3]
Color key
|
Notes Uncertain or tentative taxa are in small text; |
incertae sedis
editFlora
edit| Genus | Species | Notes | Images |
|---|---|---|---|
| Possible Algal Structures[1] |
|
Flattened, spherical structures, half an inch across. | |
Ichnogenera
edit| Genus | Species | Notes | Images |
|---|---|---|---|
| Skolithos[3] |
|
Burrows. |  |
| Helminthoidichnites[2] |
|
Burrows. | |
| Planolites[2] |
|
Burrows. | |
| Torrowangea[2] |
|
Burrows. | |
References
edit- 1 2 3 4 5 6 7 Stewart, J. H. "Upper Precambrian and Lower Cambrian Strata, in the Southern Great Basin California and Nevada" (PDF). U.S. Geological Survery. Geological Survey Professional.
- 1 2 3 4 5 6 7 Corsetti, Frank A.; Hagadorn, James W. (2003). "The Precambrian-Cambrian Transition in the Southern Great Basin, USA". The Sedimentary Record. 1 (1): 4–8. doi:10.2110/sedred.2003.1.4.
- 1 2 Peter Crimes, T. (March 1987). "Trace fossils and correlation of late Precambrian and early Cambrian strata". Geological Magazine. 124 (2): 97–119. doi:10.1017/S0016756800015922.
- ↑ Taylor, Michael E. (1966). "Precambrian Mollusc-like Fossils from Inyo County, California". Science. 153 (3732): 198–201. ISSN 0036-8075.
- 1 2 Yang, Ben; Warren, Lucas V.; Steiner, Michael; Smith, Emily F.; Liu, Pengju (March 2022). "Taxonomic revision of Ediacaran tubular fossils: Cloudina , Sinotubulites and Conotubus". Journal of Paleontology. 96 (2): 256–273. doi:10.1017/jpa.2021.95. hdl:11449/222774.
- Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.