Molluscan biozones, event/cycle chronostratigraphy, and sealevel history; a new integrated Cretaceous chronology for Northern South America

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

OSTI ID:6063459

Villamil, T; Johnson, C C; Kauffman, E G ^[1]

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1. Univ. of Colorado, Boulder (United States)

The Cretaceous marine basins of northern South America, in their evolution, record a dynamic interplay between regional and plate tectonics, sealevel history, changing paleo-ocean/paleoclimate systems, and the rates/patterns of sedimentation driven by both allocyclic and autocyclic processes. Regional interpretation of these complex interactions; and the evolution of the South American passive margin, requires a high-resolution stratigraphic system of dating and correlation. Because short-term events and dynamic processes shape the stratigraphic record, this chronology must have a resolution of <1 million years, ideally 10's-100's of ka correlation units. This resolution does not currently exist in South America, where Cretaceous radiometric dates and paleomagnetic analyses are few, event/cycle chronostratigraphy and sequence stratigraphy are not yet well developed and where current biostratigraphic resolution based on mollusks averages 1- > 2 Ma/biozone. New efforts to establish a more refined chronology for South America involve: (a) High-resolution (cm-scale) event/cycle chronostratigraphic analyses of key Colombian and Venezuelan sections; (b) search for datable ash/bentonite beds; (c) detailed paleontologic collecting to firmly establish biostratigraphic ranges of mollusks and microplankton with high biostratigraphic potential, and to formulate regional assemblage zones; and (d) integration of these diverse data through graphic correlation to provide a new chronologic standard for the region. Initial results are presented: Middle Cretaceous biozones are now resolved to <500 ka/zone; a fine-scale sequence stratigraphy and sealevel history has been determined; numerous regional physical and chemostratigraphic event beds are identified; and climate-driven cyclostratigraphy has been resolved to at least 50 ka within the passive margin sequences of Colombia and Venezuela.

• OSTI ID: 6063459
• 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
&amp; Exploration
58 GEOSCIENCES
580000 -- Geosciences
BENTONITE
CLAYS
COLOMBIA
CONTINENTAL MARGIN
CRETACEOUS PERIOD
DEVELOPING COUNTRIES
GEOLOGIC AGES
GEOLOGIC HISTORY
GEOLOGY
INORGANIC ION EXCHANGERS
INTERACTIONS
ION EXCHANGE MATERIALS
LATIN AMERICA
MATERIALS
MESOZOIC ERA
ORIGIN
PACIFIC OCEAN
PALEOCLIMATOLOGY
PALEONTOLOGY
PLATE TECTONICS
SEAS
SEDIMENTATION
SOUTH AMERICA
STRATIGRAPHY
SURFACE WATERS
TECTONICS
VENEZUELA