Nichols Magnesite deposit, Hemet, Riverside Co., California, USA
|Latitude & Longitude (WGS84):||33° 42' 39'' North , 117° 1' 41'' West|
|Latitude & Longitude (decimal):||33.71087,-117.02808|
|Köppen climate type:||Csa : Hot-summer Mediterranean climate|
A magnesite deposit located in the NW¼ sec. 30, T5S, R1W, SBM, 6.7 km (4.1 miles) SW of Hemet (center), S of Ryan Airport & Domenigani Parkway. MRDS database stated accuracy for this location is 500 meters.
NOTE: USGS MRDS database file #10064423 presents geographic coordinates (33.70837, -116.91753) that place this locality in sec. 30, T1E versus sec. 30, T1W. All 3 MRDS files state that it is in sec. 30, T1W.
Mineralization is hosted in serpentinite. Local rocks include Quaternary alluvium and marine deposits.
Workings include underground openings comprised of a 50 foot shaft.
1 valid mineral.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
|Holocene - Pliocene|
0 - 5.333 Ma
|Quaternary alluvium and marine deposits|
Age: Cenozoic (0 - 5.333 Ma)
Stratigraphic Name: Temescal Formation; Modesto Formation; Victor Formation; Alameda Formation; Aromas Red Sands; Bautista Beds; Brawley Formation; Borrego Formation; Burnt Canyon Breccia; Cabezon Fanglomerate; Campus Formation; Casitas Formation; Chemehuevi Formation; Corcoran Clay; Cushenbury Springs Formation; Dos Picachos Gravels; Dripping Springs Formation; Frazier Mountain Formation; Friant Formation; Harold Formation; Heights Fanglomerate; Hookton Formation (part); Huichica Formation; La Habra Formation; Manix Lake Beds; Mohawk Lake Beds; Montezuma Formation; Nadeau Gravel; Ocotillo Conglomerate; Orcutt Formation; Pacoima Formation; Pauba Formation; Peckham Formation; Pinto Formation; Resting Springs Formation; Riverbank Formation; Rohnerville Formation; San Dimas Formation; Shoemaker Gravel; Temecula Arkose; Battery Formation; Bay Point Formation; Colma Formation; Lindavista Formation; Lomita Marl; Merritt Sand; Millerton Formation; Palos Verdes Sand; San Pedro Formation; Sweitzer Formation; Timms Point Silt
Description: Alluvium, lake, playa, and terrace deposits; unconsolidated and semi-consolidated. Mostly nonmarine, but includes marine deposits near the coast.
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. 
0.0117 - 2.588 Ma
|Old alluvial-fan deposits|
Age: Pleistocene (0.0117 - 2.588 Ma)
Description: Moderately- to well- consolidated silt, sand, and gravel. Subunits are distinguished on basis of soil- profile development, degree of dissection, and relative position in local terrace- riser succession. On south side of San Bernardino Mountains, reddish-brown alluvial-fan deposits of primarily sand- to boulder-sized clasts are moderately consolidated and slightly to moderately dissected. They have moderate to well developed pedogenic soils (A/AB/B/Cox profiles with Bt horizons). On north side of San Bernardino Mountains, Qof deposits near east edge of quadrangle are mainly coarse debris flows consisting of angular boulders in matrix ranging from small boulders to silt. They are essentially unstratified, and have moderately well developed soil horizons and well dissected surfaces. Old fan deposits southeast of Hesperia, east of Mojave River, are stream-deposited, consisting of poorly to moderately well stratified pebble- to boulder-bearing sand, containing pebble to boulder lenses. Fan surfaces are cut by well defined channels separated by relatively smooth surfaces having moderately well developed soil horizons. West of Sheep Creek, on north side of San Gabriel Mountains, Qof fans consist of massive to poorly bedded, sand to boulder alluvium. Many show 2-m-thick soil profiles having well developed B1 horizons ranging from dark brown to orangish-brown. Moderately well consolidated; highly dissected (Kenney, 1999). In Santa Ana quadrangle, extensive Qof deposits surround Lakeview Mountains, flank both sides of Santiago Creek east of Orange, and occur at places in and along Elsinore trough.
Reference: Morton, D.M., F.K. Miller . Geologic Map of the San Bernardino and Santa Ana 30' x 60' quadrangles, California. U.S. Geological Survey Open-File Report 2006-1217. 
Saul, R.B., Evans, J.R., and Gray, C.H. (1970) Mines and mineral resources of Riverside County. California Division of Mines and Geology County Report 9 (unpublished manuscript): 888.
Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 204.
USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10064423, 10110903 & 10236775
U.S. Bureau of Mines Minerals Availability System/Mineral Industry Location System (MAS/MILS): file #0060650376.