Foraminiferal record of Oligocene-Miocene shales from the Limon Basin, eastern Costa Rica

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6654425

Cassell, D T; Sen Gupta, B K

Foraminiferal analysis of an unusually thick and continuous section of Tertiary shales from the western margin of the Limon Basin, Costa Rica, indicates that rocks from this section are older than similar facies elsewhere in the basin. Approximately 620 meters of silty shales from the Quebrada Terciopelo belong to zones N3 through N9 while the oldest shales from the rest of the basin are in N12 to N13. The lowermost N3 zone is characterized by the presence of the Late Oligocene larger foraminifera Lepidocyclina waylandvaughani and Heterostegina antillea associated with oncolite clasts in a siltstone. Shales above contain typical Early to Middle Miocene planktonic foraminifera, including Catapsydrax stainforthi, Globorotalia kugleri, G. sicanus, and G. peripheroronda. The first two species, used widely as Early Miocene markers and reported to have nonoverlapping stratigraphic ranges, are found together within a short interval in this section. This Quebrada Terciopelo sedimentary section shows the transition from a shallow nearshore environment in the Late Oligocene to an open marine outer shelf or upper slope in the Miocene. The biostratigraphic analysis demonstrates than an approximately 70 meter thick Late Oligocene (N3) to Early Miocene (N5) section is repeated. This is apparently related to normal faulting associated with the uplift of the Talamanca Mountains.

• Research Organization: Louisiana State Univ., Baton Rouge (USA)
• OSTI ID: 6654425
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580100* -- Geology & Hydrology-- (-1989)
AGE ESTIMATION
ANIMALS
CENOZOIC ERA
CENTRAL AMERICA
COSTA RICA
DEVELOPING COUNTRIES
FORAMINIFERA
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOLOGY
INVERTEBRATES
LATIN AMERICA
MICROORGANISMS
PALEONTOLOGY
PROTOZOA
ROCKS
SARCODINA
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SHALES
STRATIGRAPHY
TERTIARY PERIOD