Hydrothermal systematics, alteration, and mineralization in the Grant Canyon, Bacon Flat, and Blackburn Oil Fields, Nevada - Intriguing Parallels with Carlin-Type gold deposits

Conference · Sun Aug 01 00:00:00 EDT 1993 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:7056286

Hulen, J B; Nielson, D L ^[1]

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1. Univ. of Utah Research Institute, Salt Lake City, UT (United States)

Nevada's three known thermally active oil reservoirs-Blackburn, Bacon Flat, and Grand Canyon-share a surprisingly long list of essential attributes with the Carlin-type, low-grade, sediment-hosted gold deposits, particularly those of the Alligator Ridge mining district. Like these rich precious-metal ore bodies, the three fields (1) are hosted by Paleozoic carbonate and calcareous silici-clastic strata; (2) occur in structural or structural/stratigraphic traps sealed beneath shales or hydrothermally argillized and silicified tuffs and epiclastic debris, (3) have undergone intense fracturing and brecciation, as well as massive hydrothermal decalcification as major porosity-creating processes; (4) occupy rocks partly altered to or veined by the secondary-mineral assemblage quartz-kaolin-barite-pyrite-marcasite; (5) have a direct geothermal connection; (6) are enriched in the elements arsenic, antimony, mercury, thallium, and even contain significant traces of gold-up 50 ppb in altered Mississippian Chainmain Shale in the Blackburn field. Moreover, measured temperatures, as well as late-stage, fluid-inclusion homogenization temperatures (T[sub h]) at the fields-all in the range 100-135[degrees]C-fall within the fluid-inclusion T[sub h] span of 90-165[degrees]C recorded for multiple Alligator Ridge deposits. Fracture-controlled live oil and oil-bearing fluid inclusions in some of the Alligator Ridge ores provide further evidence of genetic similarities with the oil reservoirs. The authors suggest that the three oil fields could represent either weakly mineralized analogs of the gold deposits or an incipient phase in their evolution ultimately leading to ore mineralization.

• OSTI ID: 7056286
• Report Number(s): CONF-930947-; CODEN: AABUD2
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 77:8; Conference: Rocky Mountain section meeting of the American Association of Petroleum Geologists (AAPG), Salt Lake City, UT (United States), 12-15 Sep 1993; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
58 GEOSCIENCES
GOLD
MINERALIZATION
OIL FIELDS
PETROLEUM GEOLOGY
ANTIMONY
ARSENIC
BARITE
HYDROTHERMAL ALTERATION
KAOLIN
MARCASITE
MERCURY
NEVADA
POROSITY
PYRITE
QUARTZ
SHALES
THALLIUM
CLAYS
DEVELOPED COUNTRIES
ELEMENTS
GEOLOGIC DEPOSITS
GEOLOGY
METALS
MINERAL RESOURCES
MINERALS
NORTH AMERICA
OXIDE MINERALS
PETROLEUM DEPOSITS
RESOURCES
ROCKS
SEDIMENTARY ROCKS
SEMIMETALS
SULFATE MINERALS
SULFIDE MINERALS
TRANSITION ELEMENTS
USA
020200* - Petroleum- Reserves
Geology
& Exploration
580000 - Geosciences