Geology of the Nelson Limestone, Postel Nunatak, Patuxent Range, Antarctica

Abstract Postel Nunatak in the Patuxent Range has been previously mapped as Nelson Limestone but there was no biostratigraphic support for that interpretation until now. We confirm that limestone exposures at Postel Nunatak are at least partly correlated with the Nelson Limestone of the Neptune Rang...

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Bibliographic Details
Published in:Antarctic Science
Main Authors: Evans, Kevin Ray, McKenna, Lawrence W., Lieberman, Bruce S., Weichert, Wesley Donald, Macleod, Kenneth G.
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 2017
Subjects:
Geology
Ecology, Evolution, Behavior and Systematics
Oceanography
Argentina
Hannah
Neptune Range
Hannah Ridge
Patuxent Range
Argentina Range
Schneider Hills
Postel Nunatak
Antarc*
Antarctic Science
Antarctica
Online Access:http://dx.doi.org/10.1017/s0954102017000396
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102017000396
Description
Summary:Abstract Postel Nunatak in the Patuxent Range has been previously mapped as Nelson Limestone but there was no biostratigraphic support for that interpretation until now. We confirm that limestone exposures at Postel Nunatak are at least partly correlated with the Nelson Limestone of the Neptune Range, 160 km north-east, and are not correlative with the lower Cambrian Schneider Hills Limestone of the Argentina Range. Upper beds have yielded the trilobites Suludella? davnii Palmer & Gatehouse, 1972 and Solenopleura pruina Palmer & Gatehouse, 1972, which provide a basis for assignment to Cambrian Series 3 (late middle Cambrian), within the Drumian or lower Guzhangian stages. Limestone beds were deposited in a shallow marine setting, ranging from supratidal to lagoonal facies with rare subtidal intervals. These settings contrast with deeper water facies of the Neptune Range. Despite limitations in sampling density, isotopic analysis indicates that a greater than +2.5‰ shift in δ 13 C is consistent with δ 13 C trends documented for the Drumian Stage. Because the upper and lower contacts at Postel Nunatak are covered by snow and ice, the relationship with rocks mapped as the Patuxent Formation in the Patuxent Range remains uncertain, but part of it may belong to the Precambrian Hannah Ridge Formation.

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