The changing course of the Orinoco River during the neogene
- Universidad Central de Venezuela, Caracas (Venezuela)
Recent studies have revealed that the varied fresh-water vertebrate fossil fauna of the Urumaco Formation in northwestern Falcon, of Late Miocene age, belongs biogeographically to the Orinoco River system. This makes possible to chart the changing course of the Orinoco River through the Neogene. The Misoa delta of Lake Maracaibo, of middle Eocene age, was probably constructed by a proto-Orinoco river that ran in a south-north direction, draining the Central Cordillera of Colombia and the Guayana Highlands. The late Eocene uplifting of western Venezuela changed the paleogeographic setting, with no evidence of delta-building during the Oligocene. In the earliest Miocene, the Falcon Basin was the site of marine shale sedimentation. In the second half of the Early Miocene, a deltaic sequence was initiated in northwestern Falcon that continued, except for a transgressive episode, until the end of the Middle Miocene, depositing a total thickness of over 2.5 km. The Urumaco overlies this sequence and its vertebrate fauna indicates that the river that built the previous delta was the proto-Orinoco. The initial uplifting of the northern part of the Andes and the western edge of the Caribbean Mountains can thus be dated to occur at the end of the Middle Miocene, causing the distal course of the river to move to a west-east direction. The sedimentary record of the Orinoco River delta appears in the Maturin Basin of eastern Venezuela at the end of the Miocene, and is especially evident in Trinidad and the Columbus Basin during the Pliocene and Pleistocene.
- OSTI ID:
- 6064825
- Report Number(s):
- CONF-930306-; CODEN: AABUD2
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 77:2; Conference: International congress of the American Association of Petroleum Geologists (AAPG), Caracas (Venezuela), 14-17 Mar 1993; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
Similar Records
Misoa formation sandstone diagenesis, blocks III and V, Maracaibo Basin, Venezuela
Cenozoic uplift of the Northerm Margin of the Guayana Shield, Venezuela, and its influence on the distribution of mineral deposits
Related Subjects
58 GEOSCIENCES
CARBONACEOUS MATERIALS
DEPOSITION
COLOMBIA
GEOLOGIC HISTORY
RIVERS
MAPPING
SEDIMENTARY BASINS
ORIGIN
TRINIDAD AND TOBAGO
VENEZUELA
ANDES
EOCENE EPOCH
FRESH WATER
MIOCENE EPOCH
OROGENESIS
PALEONTOLOGY
RIVER DELTAS
SEDIMENTATION
SHALES
THICKNESS
CENOZOIC ERA
COASTAL REGIONS
DEVELOPING COUNTRIES
DIMENSIONS
GEOLOGIC AGES
GEOLOGIC STRUCTURES
HYDROGEN COMPOUNDS
ISLANDS
LATIN AMERICA
LESSER ANTILLES
MATERIALS
MOUNTAINS
OXYGEN COMPOUNDS
ROCKS
SEDIMENTARY ROCKS
SOUTH AMERICA
STREAMS
SURFACE WATERS
TERTIARY PERIOD
WATER
WEST INDIES
020200* - Petroleum- Reserves
Geology
& Exploration
580000 - Geosciences