Field and Detrital Zircon Constraints from Late Paleozoic Glacial Paleogeography in Oman

Joe Martin¹, Jonathan Redfern², Matthew Horstwood³, Ian Millar³, and Brian Williams^4
1Exploration and Production, Shell International, Rijswijk, Netherlands
²School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, United Kingdom
³NERC Isotope Geosciences Laboratory, NERC, Keyworth, United Kingdom
⁴Department of Geology and Petroleum Geology, University of Aberdeen, Aberdeen, United Kingdom

The difficulties involved in reconstructing glacier-influenced sedimentary environments are well illustrated with the Al Khlata Formation (AKF) of the Sultanate of Oman, deposited during the Late Paleozoic Gondwanan ice age. Whereas detailed palynological dating of the subsurface AKF over the last several decades has resulted in its sub-division into 3 unconformity-bound production units (from oldest to youngest, P9, P5, P1), only P5 is exposed. This lack of exposure combined with the typical problems of reconstructing glacial environments associated with, for example, pronounced erosion and facies variability, have resulted in widely different paleogeographic models for the AKF. Our study presents a revised paleogeography for the Late Paleozoic ice age of Oman, based on provenance analysis utilizing uranium-lead dating and hafnium-isotope geochemistry of detrital zircons from all stratigraphic intervals of the AKF. When integrated with field measurements and considered within context of existing biostratigraphy and regional studies, the results demonstrate the evolution of the Late Paleozoic ice age in Oman was more complex than previously suggested and occurred at a variety of scales from alpine to continental.

AAPG International Conference and Exhibition, Cape Town, South Africa 2008 © AAPG Search and Discovery