Sergio A. Marenssi, 2006. "Eustatically controlled sedimentation recorded by Eocene strata of the James Ross Basin, Antarctica", Cretaceous–Tertiary High-Latitude Palaeoenvironments: James Ross Basin, Antarctica, J. E. Francis, D. Pirrie, J. A. Crame
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The Eocene La Meseta Formation is an unconformity-bounded unit that records the geological evolution of the James Ross Basin, NE Antarctic Peninsula, during a period of decreasing tectonism and a lull in volcanic activity. This unit represents a composite incised valley, filled with deltaic, estuarine and shallow-marine deposits showing a landwards facies shift that indicates deposition during an overall sea-level rise. The six unconformity-based internal units (Valle de las Focas, Acantilados, Campamento, Cucullaea I, Cucullaea II and Submeseta allomembers) are interpreted to represent minor-scale regressive-transgressive events. Geological, palaeontological and new strontium isotopic ages allow the correlation of base-level changes with second- and third-order eustatic sea-level fluctuations. The base of the La Meseta Formation is correlated with a global 56 Ma lowstand in sea level followed by a main episode of flooding between 54.3 and 52.4 Ma. The base of the Cucullaea I Allomember is correlated with the well-known late Ypresian (49 Ma) lowstand, and the base of the Submeseta Allomember with the 36 Ma lowstand. Correlation of Eocene sea-level fluctuations in the northern Antarctic Peninsula with the global sea-level curve strengthens the concept of global syncroneity of the eustatic sea-level curve.
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High-latitude settings are sensitive to climatically driven palaeoenvironmental change and the resultant biotic response. Climate change through the peak interval of Cretaceous warmth, Late Cretaceous cooling, onset and expansion of the Antarctic ice sheet, and subsequently the variability of Neogene glaciation, are all recorded within the sedimentary and volcanic successions exposed within the James Ross Basin, Antarctica. This site provides the longest onshore record of Cretaceous–Tertiary sedimentary and volcanic rocks in Antarctica and is a key reference section for Cretaceous–Tertiary global change. The sedimentary succession is richly fossiliferous, yielding diverse invertebrate, vertebrate and plant fossil assemblages, allowing the reconstruction of both terrestrial and marine systems. The papers within this volume provide an overview of recent advances in the understanding of palaeoenvironmental change spanning the mid-Cretaceous to the Neogene of the James Ross Basin and related biotic change, and will be of interest to many working on Cretaceous and Tertiary palaeoenvironmental change.