Cenozoic oblique collision of South American and Caribbean plates: New evidence in the Coastal Cordillera of Venezuela and Trinidad
- Northwestern Univ., Evanston, IL (United States)
- Carnegie Institute of Washington (United States)
- Ohio State Univ., Columbus (United States)
The hinterland of the Caribbean Mts. orogen in Trinidad and Venezuela contains schist and gneiss whole protoliths are wholly or partly of continental provenance. The hinterland lies between the foreland thrust belt and terranes. The terranes are alien to continental South America (SA) and may have proto-Caribbean or Caribbean plate origins. The hinterland rocks were widely thought to come from sediments and granitoids of Mesozoic protolithic ages and to be of Cretaceous metamorphic age. Such rocks are now know to be of at least two or more types, as follows: (1) low grade, protoliths of pre-Mesozoic basement and shelfal cover of uncertain age range, inboard locus, Oligocene to mid-Miocene metamorphic ages younging eastward (Caracas, Paria, and Northern Range belts), and (2) higher grade including high P/T, varies protoliths of uncertain age range, Cretaceous and ( )early Paleogene metamorphic ages (Tacagua, Araya, Margarita). The geometry, protoliths, structures, and metamorphic ages of type 1 parautochthoneity and an origin as a thickened wedge of crust-cored passive margin cover. The wedge grew by accretion between about 35 and 20 Ma during oblique transport toward the foreland. The diachroneity of metamorphism implies, as does the timing of foreland deformation, that the wedge evolved in a right-oblique collision between northern SA and terranes moving wholly or partly with the Caribbean plate since the Eocene. Type 2 rocks probably came with the terranes and are products of convergent zone tectonics, either in the proto-Caribbean plate. The hinterland boundaries are brittle thrusts that are out of sequence and imply progressive contraction from mid-Cenozoic to the present.
- OSTI ID:
- 6063673
- Report Number(s):
- CONF-930306--
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Vol. 77:2; ISSN 0149-1423; ISSN AABUD2
- Country of Publication:
- United States
- Language:
- English
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58 GEOSCIENCES
580000 -- Geosciences
ANDES
CENOZOIC ERA
DEFORMATION
DEVELOPING COUNTRIES
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
GEOMORPHOLOGY
ISLANDS
LATIN AMERICA
LESSER ANTILLES
METAMORPHISM
MIOCENE EPOCH
MOUNTAINS
ORIGIN
PLATE TECTONICS
ROCKS
SEDIMENTS
SOUTH AMERICA
TECTONICS
TERTIARY PERIOD
TRINIDAD AND TOBAGO
VENEZUELA
WEST INDIES