Cenozoic uplift of the Northerm Margin of the Guayana Shield, Venezuela, and its influence on the distribution of mineral deposits

Conference · Mon Feb 01 04:00:00 EST 1993 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:5941520

Olmore, S D ^[1]; Garcia, A ^[2]; Antonia, S C ^[3]

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1. S.D. Olmore Associates Inc., Golden, CO (United States)
2. CVG-Tecnica Minera C.A., Puerto Ordaz (Venezuela)
3. Lagoven S.A., Caracas (Venezuela)

We present new ideas regarding the Cenozoic intraplate tectonics of the northern margin of the Guayana Shield. During Caribbean Orogeny tectonic transpression induced by right-lateral shear brought about the uplift of a 500 km by 200 km, east-northeast-trending elongate region south of the Orinoco River in south-central Venezuela-Uplifted Imataca Block (UIB). Erosional stripping of mineralized greenstone units from the UIB exposed a high-grade metamorphic core of quartz-feldspar granulite gneiss of Archean age. A 1000-meter-thick section of deltaic sediments from erosion of the UIB were deposited in the marginal basin to the north during Miocene and younger time. These sedimentary units host the Orinoco heavy-oil belt. The UIB is bounded on the north by a series of east-northeast-trending step faults that lie along the approximate trace of the Orinoco River. The UIB is bounded on the south by the Guri fault zone. Numerous sub-parallel faults within the exposed Archean block show evidence of late Cenozoic, post-uplift, right-lateral and normal displacement. Some conclusions: (1) high-grade Archean granulite or praqneiss may underlie portions of the Proterozoic greenstone and granite-gneiss terrain of the Guayana shield to the south; (2) differences in El Pao and Cerro Bolivar iron ores are explained by differential erosional stripping accompanying block uplift. (3) The juxtaposition of oil-bearing Cenozoic sediments and metal-rich Archean and lower Proterozoic greenstone units by Mesozoic and Cenozoic faulting makes central Venezuela one of the richest mineral-bearing provinces of the world.

• OSTI ID: 5941520
• Report Number(s): CONF-930306--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 77:2
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
CONTINENTAL MARGIN
DEVELOPING COUNTRIES
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
LATIN AMERICA
MINERAL RESOURCES
MINERALS
ORIENTATION
ORIGIN
OROGENESIS
PETROLEUM DEPOSITS
RESERVES
RESOURCES
SEDIMENTARY BASINS
SOUTH AMERICA
TECTONICS
VENEZUELA