Scientific data near [38.99957,-120.79185]

Search area extends approximately 4.5 km east-west and 5.7 km north-south.

Geographic context

Counties, states, countries, continents, or oceans
Placer	county
California	state
United States	country
North America	continent
Land	continent
Map quadrangles, from USGS or Canadian NTS
Georgetown	quadrangle 1:24,000 scale
Placerville	quadrangle 1:100,000 scale
Sacramento	quadrangle 1:250,000 scale
Watershed boundaries (USGS hydrologic units)
North Fork American	hydrologic unit
Lower Sacramento	hydrologic accounting unit
Sacramento	hydrologic subregion
California	hydrologic region
Areas administered by US Federal agencies
Tahoe National Forest	National Forest
National Forest FS	Type of land area
FS	Federal land areas administered by FS

Geology of US states

Digital geologic maps of the US states with consistent lithology, age, GIS database structure, and format

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Unit	State	Lithology
Jurassic marine rocks, unit 1 (Western Sierra Nevada and Western Klamath Mountains)	CA	Triassic to Late Jurassic
Paleozoic marine rocks, undivided, unit 4 (Western Sierra Nevada)	CA	Ordovician to Triassic
Tertiary pyroclastic and volcanic mudflow deposits, unit 9 (Cascade Range)	CA	Tertiary (2-24 Ma)
Ultramafic rocks, chiefly Mesozoic, unit 2 (Western Sierra Nevada and Klamath Mountains)	CA	Late Proterozoic(?) to Early Jurassic

Airborne geophysical surveys

Aerial surveys of magnetic anomaly and gamma ray emission; older surveys were analog record which have been digitized, newer surveys collected data in digital form.

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ID	Data type	Description
North Sierra Foothills	M-D	North Sierra Foothills 8481 line km with spacing 0.80 km over parts of CA
Chico	M/R-D	Chico 4869 line km with spacing 4.80 km over parts of CA-NV
Sacramento	M/R-D	Sacramento 5005 line km with spacing 4.80 km over parts of CA

Estimates of undiscovered mineral resources

National Mineral Resource Assessment 1998: Estimates of the number of undiscovered mineral resources of gold, silver, copper, lead, and zinc within identified permissive tracts (geographic areas in which mineral deposits may form).

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Tract	Deposit Type	Mineralization age
PC03	Skarn Cu	Mesozoic
PC08	Porphyry Cu	Mesozoic
PC40	Low-sulfide Au-quartz vein	Mesozoic

The continental crust

Seventy-seven major components of the North American continent were delineated at a general scale (1:5,000,000); including the general composition, geological environment, and types of primary metals endowments that can be expected in each domain.

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Domain	Crust type	Region
Calaveras-Baker	Accretionary wedge	Western Cordillera

Geochemistry of stream sediments in the US from the NURE-HSSR database

National-scale geochemical analysis of stream sediments and soils in the US collected and analyzed under the National Uranium Resource Evaluation program.

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Sample ID	Date collected	Sample type
5190011	1980-04-30	Soil sample sieved to less than 149 microns (-100 mesh).

Asbestos mines, prospects, and occurrences in the US

Location and mineralogical characteristics of former mines, prospects, and occurrences of asbestos in the continental US. No asbestos producing mines are currently active. Data here are drawn from several previously published reports.

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Deposit name	Deposit type	Location
unnamed occurrence (near Forest Hill)	occurrence	Placer, CA

Podiform chromite deposits

Location and characteristics of 1,124 individual mineral deposits of this type, with grade and tonnage models for chromium as well as several related elements.

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Record	Type	Comment
Black Rock Chrome

Mineral Resource Data System

MRDS describes metallic and nonmetallic mineral resources throughout the world. Included are deposit name, location, commodity, deposit description, geologic characteristics, production, reserves, resources, and references.

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Site name	Development	Commodities
Three Queens	Past Producer	AU PB
Little Greek Claims	Producer	CR
Josephine	Past Producer	AU
Black Rock Chrome Deposit	Past Producer	CR
Chrome Divide	Past Producer	CR
Dry Hill and Blue Jay	Past Producer	AU
West Quartz	Past Producer	AU
Perkins Consolidated	Occurrence	AU
Buckeye Hill Flora	Occurrence	AU
Murzo Brass	Occurrence	AU
Lucky Strike Occurrence	Past Producer	CR
California and Virginia	Occurrence	AU
Unnamed	Past Producer	AU
Dry Hill	Unknown	AU
Barnes	Unknown	AU
Josephine	Unknown	AU
Josephine Mine	Unknown	AU
Eva Lode	Unknown	AU
Homestake	Unknown	AU
Little Greek Claims	Past Producer	CR
Independent	Past Producer	AU
Gray Eagle Cliff	Unknown	AU
Homestake	Occurrence	AU
Middle Fork	Occurrence	AU
Worthington	Unknown	AU
Moss Ledge	Producer	AU
Rio Del Oro	Producer	AU
Mcaloney Placer	Unknown	AU
Prospect	Unknown	AU
E A Garrison Prospects	Occurrence	CR
Marigold	Past Producer	AU AG
Murzo	Unknown	AU
Hope	Unknown	AU
Unnamed Location	Occurrence	AU
Middle Fork	Occurrence	AU
California & Virginia Placer Mines	Unknown	AU
Lucky Strike	Past Producer	CR
Sellier	Unknown	AU
Marigold	Past Producer	AU AG
Eva Lode	Past Producer	AU
Independent	Producer	AU
Ladies Canyon	Unknown	AU
Josephine Shields	Occurrence	AU
Prospects 2	Occurrence	AU
Perkins Cons	Past Producer	AU
Carpenter Ranch	Unknown	AU
Winfred Shirley	Unknown	AU
Chrome Divide	Past Producer	CR
Black Rock Chrome	Past Producer	CR
Moss Ledge	Past Producer	AU
Blue Jay	Unknown	AU
Unnamed Mine	Unknown	AU
Spanish	Unknown	AU
Prospect	Unknown	AU
Perkins Consolidated	Occurrence	AU
Maus Tunnel	Unknown	AU
Rio Del Oro	Past Producer	AU
Three Queens	Past Producer	AU
Duffy Property	Occurrence	AU

An index to PGE-Ni-Cr deposits and occurrences in selected mineral-occurrence databases (web-accessible database)

A compendium of references to previously published databases and database records that describe PGE, nickel, and chromium deposits and occurrences. These data show where to obtain more detailed information about each deposit or occurrence.

Database Home

Deposit name	Deposit type	Location
Lucky Strike Occurrence	Past Producer	California, United States
Chrome Divide	Past Producer	California, United States
Black Rock Chrome Deposit	Past Producer	California, United States
Black Rock Chrome	Past Producer	California, United States
Chrome Divide	Past Producer	California, United States
Lucky Strike	Past Producer	California, United States
E A Garrison Prospects	Occurrence	California, United States
Forest Hill District	Past Producer	California, United States

National Geochemical Database: Soil

Geochemical analysis of soil samples from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are from the continental US and Alaska.

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Sample ID	Sample source	Sample notes
C239059	unknown	NURE Archived SOILS

Global assessment of undiscovered copper resources

Deposits, prospects, and permissive tracts for porphyry and sediment-hosted copper resources worldwide, with estimates of undiscovered copper resources.

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Tract name	Deposit type	Geology
Cascade Arc	porphyry copper	U.S. part of a continental margin arc that formed during subduction of the Pacific and Juan de Fuca plates beneath western North America
Sierran Arc	porphyry copper	A composite island-continental margin arc that formed during subduction of the Farallon Plate beneath western North America
Western U.S. and Sonoran Desert Jurassic Arc	porphyry copper	U.S. and Mexican parts of a composite island-continental margin arc that formed during subduction of the Farallon Plate beneath western North America

Prospect- and mine-related features on USGS topographic maps

Symbols indicating mining-related features digitized from historical USGS topographic maps in the western part of the conterminous US. Includes prospect pits, mine shafts and adits, quarries, open-pit mines, tailings piles and ponds, gravel and borrow pit

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Feature ID	Feature type	Feature name
Adit	point	Josephine Mine
Adit	point	Josephine Mine
Adit	point	Homestake Mine
Adit	point	Homestake Mine
Adit	point
Adit	point	Three Queens Mine
Adit	point	Three Queens Mine
Adit	point