Cenozoic prograding sequences of the Antarctic continental margin - What balance between structural and eustatic control

Conference · Tue May 01 04:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:6761832

Cooper, A K ^[1]; Barrett, P ^[2]; Hinz, K ^[3]; Stagg, H ^[4]; Traube, V ^[5]

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1. Geological Survey, Menlo Park, CA (USA)
2. Victoria Univ., Wellington (New Zealand)
3. Federal Geosciences Institute, Hannover (West Germany)
4. Bureau of Mineral Resources, Canberra (Australia)
5. Sevmorgeologia, Leningrad (USSR)

Multichannel seismic reflection profiles across the Antarctic continental margin commonly reveal prograding sedimentary sequences that are bounded by unconformities. These sequences are as much as 5 km thick and, where sampled, are composed entirely of late Eocene( )-early Oligocene and younger glacial rocks. On nonpolar margins, prograding sequences generally are attributed to relative changes in sea level, sediment supply, and tectonism. Around Antarctica, ice sheets have also been important in controlling the geometry and location of prograding sequences. The Antarctic sequences may provide a proximal record of major Cenozoic ice volume changes and related sea level changes not obtainable from low-latitude continental shelves. Presently, the Antarctic record is poorly known because of limited core data. Two categories of prograding (P) and aggrading (A) sigmoidal sequences are observed around Antarctica: (1) P sequences that build principally outward (common) and (2) AP sequences that build largely upward and outward (less common). P sequences may result principally from grounded ice sheets, and AP sequences from open-marine basinal processes. Major rift embayments of Antarctica (e.g., eastern Ross Sea eastern Weddell Sea Lambert graben Wilkes basin) are also pathways for major ice movement. In general, most areas with P sequences lie within or adjacent to Mesozoic or older rift embayment, whereas the primary area with AP sequences (eastern Ross Sea) lies within a likely Cenozoic rift embayment. The Pacific side of the Antarctic Peninsula where Cenozoic ice sheets and Cenozoic tectonism have been active, is also marked by a P sequence. Scientific drilling on the Antarctic continental shelf has recovered openwater glacial deposits (Ross Sea) as well as glacial diamicts that were deposited beneath and in front of grounded glacier ice (Ross Sea and Prydz Bay).

• OSTI ID: 6761832
• Report Number(s): CONF-900605--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 74:5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
ANTARCTIC REGIONS
ANTARCTICA
CENOZOIC ERA
CONTINENTAL MARGIN
GEOLOGIC AGES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
POLAR REGIONS
RIFT ZONES
SEDIMENTARY BASINS