Rhodes Marsh (Virginia Marsh), Mineral County, Nevada, USAi

Regional Level Types
Rhodes Marsh (Virginia Marsh)	- not defined -
Mineral County	County
Nevada	State
USA	Country

Tectonics: Basin And Range

Deposit: First production year: 1862 (salt); about 1872 (borates) playa-type borate deposit. The marsh is 2.5 miles long in a ne-s W direction and As much As 1.5 miles wide, with an area of about 3 sq miles. Halite is most pure in a mile square area in the central part of the playa. Cottonball ulexite was the main borate ore and occurs in soft sediments within a foot or two of the surface along the west and north margins of the marsh; the ulexite areas partially surround the central halite area. Thenardite occurs in lenses 3-5 ft thick lying 2-6 ft belo W the surface. Borax/tincalconite is widely distributed As a crust 1-3 inches thick in the southern part of the playa and As crystals up to an inch in diameter in the near-surface mud to the west, southwest, and southeast of the main halite area. The thenardite lenses occur principally in a band that encircles most of the central halite area and mirabilite occurs mostly As disseminated crystals beneath the thenardite. A near surface layer of mirabilite up to 15 ft thick has been reported in one area. Sodium carbonate has been reported As a surface crust in the southeastern part of the playa.

Deposit type: Lacustrine borates

Development: First worked in 1860's when exploited for salt which was shipped by camel to virginia city for use in extracting silver and gold from the comstock ores. In 1870's, borax was discovered and much "cotton ball" ulexite was recovered until discovery of more easily recovered deposits at death valley. The marsh was also prospected for potash, but the content of the brines was too low. In the late 1920's and early 1930's, sodium sulfate was produced from mirabilite and thenardite.

Geology: Geol.desc: thenardite occured As lenses 3 to 5 feet thick overlain by 2 to 6 feet of silt and salt

Fossils

There are 1 fossil localities from the PaleoBioDB database within this region.

BETA TEST - These data are provided on an experimental basis and are taken from external databases. Mindat.org has no control currently over the accuracy of these data.

Occurrences	6
Youngest Fossil Listed	251 Ma (Early/Lower Triassic)
Oldest Fossil Listed	252 Ma (Early/Lower Triassic)
Stratigraphic Units	Unit No. Occurrences Age Candelaria 6 252.17 - 251.3 Ma (Phanerozoic)
Fossils from Region	Click here to show the list.
Accepted Name Hierarchy Age Lingulidae family Animalia : Brachiopoda : Lingulata : Lingulida : Lingulidae 252.17 - 251.3 Ma Phanerozoic Microconchus genus Animalia : Mollusca : Tentaculita : Microconchida : Microconchus 252.17 - 251.3 Ma Phanerozoic Ophiceratidae family Animalia : Mollusca : Cephalopoda : Ammonoidea : Ophiceratidae 252.17 - 251.3 Ma Phanerozoic Claraia stachei species Animalia : Mollusca : Bivalvia : Pectinida : Pterinopectinidae : Claraia : Claraia stachei 252.17 - 251.3 Ma Phanerozoic Claraia aurita species Animalia : Mollusca : Bivalvia : Pectinida : Pterinopectinidae : Claraia : Claraia aurita 252.17 - 251.3 Ma Phanerozoic Claraia clarai species Animalia : Mollusca : Bivalvia : Pectinida : Pterinopectinidae : Claraia : Claraia clarai 252.17 - 251.3 Ma Phanerozoic
Fossil Localities	Click to show 1 fossil locality

References

Other Databases

Link to USGS MRDS:	10103596