Lower cretaceous organic-rich sediments drilled on Antarctic continental margin during ODP Leg 113

Conference · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5924157

O'Connell, S

Lower Cretaceous organic-rich sediments were recovered below a major unconformity at two sites on the eastern Weddell Sea margin during ODP Leg 113. No age overlap exists between the two sites. A more continuous Cretaceous section was previously recovered at DSDP Site 511 on the Falkland plateau. Site 692 (2,880 m water depth) is located on a mid-slope bench in Wegener Canyon. Early Cretaceous-age (pre-Albian) sediments extend from 53-98 m below sea floor (mbsf) and are dominated by organic-rich nannofossil claystone. Macrofossils (e.g., belemites and ammonites), thin carbonate lenses (<1 cm), and water escape structures are abundant. Thin beds of devitrified ash, bioturbation, and graded bedding are present. Site 693 (2,360 m water depth), 30 km west of Site 692 on the canyon's outer rim, recovered Albian-age organic-rich claystones and mudstones from 416-483 mbsf. Site 693 sediments have lower organic contents than those at Site 692. Glauconite is common in the upper part of the unit. Well-preserved diatoms and diatomite layers suggest high productivity.

• OSTI ID: 5924157
• Report Number(s): CONF-880301-
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
&amp; Exploration
58 GEOSCIENCES
580500 -- Oceanography-- (1980-1989)
ANTARCTIC REGIONS
ANTARCTICA
ATLANTIC OCEAN
BIOGEOCHEMISTRY
CHEMISTRY
CONTINENTAL MARGIN
CRETACEOUS PERIOD
FOSSILS
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGY
MESOZOIC ERA
ORGANIC MATTER
POLAR REGIONS
SEAS
STRATIGRAPHY
SURFACE WATERS
WEDDELL SEA