Evidence of rapid Cenozoic uplift of the shoulder escarpment of the Cenozoic West Antarctic rift system and a speculation on possible climate forcing

Journal Article · Sun Mar 31 23:00:00 EST 1991 · Geology; (USA)

DOI:https://doi.org/10.1130/0091-7613(1991)019<0315:EORCUO>2.3.CO;2· OSTI ID:5657215

Behrendt, J C ^[1]; Cooper, A ^[2]

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1. Geological Survey, Denver, CO (USA)
2. Geological Survey, Menlo Park, CA (USA)

The Cenzoic West Antarctic rift system, characterized by Cenozoic bimodal alkalic volcanic rocks, extends over a largely ice-covered area, from the Ross Sea nearly to the Bellingshausen Sea. It is bounded on one side by a spectacular 4-to 5-km-high rift-shoulder scarp (maximum bedrock relief 5 to 7 km) from northern Victoria Land-Queen Maud Mountains to the Ellsworth-Whitmore-Horlick Mountains. Jurassic tholeiites crop out with the late Cenozoic volcanic rocks along the section of the Transantarctic Mountains from northern Victoria Land to the Horlick Mountains. The Cenozoic rift shoulder diverges here from the Jurassic tholeiite trend, and the tholeiites are exposed discontinuously along the lower elevation (1-2 km) section of the Transantarctic Mountains to the Weddell Sea. Various lines of evidence, no one of which is independently conclusive, lead the authors (as others have also suggested) to interpret the following. The Transantarctic Mountains part of the rift shoulder (and probably the entire shoulder) has been rising since about 60 Ma, at episodic rates of {approximately}1 km/m.y., most recently since mid-Pliocene time, rather than continuously at the mean rate of 100m/m.y. Uplift rates vary along the scarp, which is cut by transverse faults. The authors speculate that this uplift may have climatically forced the advance of the Antarctic ice sheet since the most recent warm period. They suggest a possible synergistic relation between episodic tectonism, mountain uplift, and volcanism in the Cenozoic West Antarctic rift system and waxing and waning of the Antarctic ice sheet beginning about earliest Oligocene time.

• OSTI ID: 5657215
• Journal Information: Geology; (USA), Journal Name: Geology; (USA) Vol. 19:4; ISSN GLGYB; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ANTARCTIC REGIONS
ANTARCTICA
CENOZOIC ERA
GEOLOGIC AGES
GEOLOGIC HISTORY
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOLOGY
GLACIERS
GROUND UPLIFT
ICE
IGNEOUS ROCKS
MOUNTAINS
OROGENESIS
PALEOCLIMATOLOGY
PALEONTOLOGY
PLIOCENE EPOCH
POLAR REGIONS
RIFT ZONES
ROCKS
SYNERGISM
TECTONICS
TERTIARY PERIOD
VOLCANIC ROCKS
VOLCANISM