Sandstone Detrital Modes and Basinal Setting of the Trinity Peninsula Group, Northern Graham Land, Antarctic Peninsula: a Preliminary Survey

  1. Garry D. Mckenzie
  1. J. L. Smellie

Published Online: 21 MAR 2013

DOI: 10.1029/GM040p0199

Gondwana Six: Structure, Tectonics, and Geophysics

Gondwana Six: Structure, Tectonics, and Geophysics

How to Cite

Smellie, J. L. (1987) Sandstone Detrital Modes and Basinal Setting of the Trinity Peninsula Group, Northern Graham Land, Antarctic Peninsula: a Preliminary Survey, in Gondwana Six: Structure, Tectonics, and Geophysics (ed G. D. Mckenzie), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM040p0199

Author Information

  1. British Antarctic Survey, Natural Environment Research Council, High Cross, Cambridge, United Kingdom Cb3 Oet

Publication History

  1. Published Online: 21 MAR 2013
  2. Published Print: 1 JAN 1987

ISBN Information

Print ISBN: 9780875900643

Online ISBN: 9781118664483

SEARCH

Keywords:

  • Gondwana(Geology)—Congresses;
  • Geology,Structural—Congresses

Summary

Sandstone detrital modes for a representative sample of the Trinity Peninsula Group in northern Graham Land are described and assessed. Whereas the volumetrically dominant quartz and feldspar were derived principally from erosion of a plutonic and high-rank metamorphic terrane, the lithic population was derived mainly from a volcanic cover. The data clearly indicate the presence of two major sandstone suites (petro-facies I and II) with distinctive and probably separate provenances. Further scope for subdivision is limited by the small sample set, but four petrofacies (Ia, Ib, IIa, and IIb) may be present, three of which correspond with previously described lithostratigraphical units (Legoupil, Hope Bay, and View Point formations). The sample distribution and detrital modes enable approximate geographical limits to be assigned to each petrofacies for the first time, although the nature of the boundaries (stratigraphical or structural) is unknown. Petrofacies II could have been derived from an active magmatic arc and deposited in a forearc basin (sensu lato) or series of basins at a major consuming margin. Petrofacies I is a much more quartzose suite, although otherwise petrographically very similar to petrofacies II. Its depositional setting is ambiguous on the basis of the data presently available, and deposition can only be said to have occurred at either an active or a passive continental margin. Finally, there is the possibility that strike-slip faulting has structurally shuffled the Trinity Peninsula Group, causing the pronounced age and compositional contrasts observed.