Biostratigraphy of Tallahatta Formation (Eocene) in Eastern Gulf Coastal Plain and revised age for Claiborne Stage

Conference · Thu Sep 01 04:00:00 EDT 1983 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:6626198

Bybell, L M; Gibson, T G

Five continuous core holes drilled downdip of the outcrop belt of the Tallahatta Formation from western Georgia to eastern Alabama yielded calcareous inner neritic sand and clay containing calcareous nannofossils and foraminifers. The occurrence of these biostratigraphically useful groups in the subsurface Tallahatta allows the reliable dating of the entire formation; this has been difficult in the past because of the dominance in the outcrop belt of heavily leached, noncalcareous coarse clastics and sparsely fossiliferous siliceous clay and silt. Fossilferous sand at the base of the Tallahatta generally overlies carbonaceous clay of the Hatchetigbee Formation. These lowest Tallahatta strata contain calcareous nannofossils diagnostic of Zone NP12 of Martini; overlying these strata are beds placed in Zone NP13. The uppermost Tallahatta beds in the core holes and in the Little Stave Creek outcrop section in western Alabama are assigned to Zone NP14; no positive evidence for strata belonging to Zone NP15 was found. Erosion surfaces separate the sediments belonging to each of the three calcareous nannofossil zones. On the basis of foraminiferal assemblages, the strata belonging to Zone NP12 and the lower part of Zone NP13 are interpreted as probably representing shallow-marine deposits; sediments in the upper part of Zone NP13 and Zone NP14 were probably deposited in somewhat deeper inner-shelf environments. Zones NP12 and NP13 are normally placed in the lower Eocene of the intercontinental correlation charts, whereas Zone NP14 has been considered entirely middle Eocene, or straddling the boundary. Most of the Tallahatta Formation, including those strata considered to represent the basal Meridian Sand Member, is therefore of early Eocene age.

• Research Organization: Geological Survey, Reston, VA
• OSTI ID: 6626198
• Report Number(s): CONF-8310301-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 67:9
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580100* -- Geology & Hydrology-- (-1989)
AGE ESTIMATION
ALABAMA
ANIMALS
CENOZOIC ERA
DRILL CORES
FEDERAL REGION IV
FORAMINIFERA
FOSSILS
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGY
GEORGIA
GULF COAST
INVERTEBRATES
MICROORGANISMS
NORTH AMERICA
PROTOZOA
SARCODINA
STRATIGRAPHY
TERTIARY PERIOD
USA