--> Integrating Sedimentology and Ichnology in the Beacon Supergroup, Central Transantarctic Mountains, Antarctica to Clarify Paleoenvironmental Interpretations and Refine Basin Analysis
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Integrating Sedimentology and Ichnology in the Beacon Supergroup, Central Transantarctic Mountains, Antarctica to Clarify Previous HitPaleoenvironmentalNext Hit Interpretations and Refine Basin Previous HitAnalysisNext Hit

Abstract

In order to develop accurate Previous HitpaleoenvironmentalNext Hit models for the evolution of ancient paleopolar fluvial-deltaic-shallow-marine depositional systems, such as those preserved in strata of the Beacon Supergroup in the Central Transantarctic Mountains, we employ a multidisciplinary approach that integrates sedimentology, stratigraphy, and ichnology. This approach helped solidify our model of a river-dominated Permian deltaic succession in the Mackellar-Fairchild Formations (Fms) at Turnabout Ridge and refine our model of a fluvio-lacustrine succession containing rivers, lakes, and forests in the Buckley-Fremow Fms at Lamping Peak. Our goal is to (1) reconstruct these paleopolar ecosystems, (2) clarify the forces driving Previous HitpaleoenvironmentalNext Hit and basin evolution (e.g. tectonics, fluctuating base level, climate change, autogenic processes), (3) refine high-paleolatitude reservoir models, and (4) provide better models for the response of modern polar ecosystems to a warming world. Facies and stratal architectures of the Mackellar-Fairchild Fms were found to exhibit gross similarities to those of the river-flood dominated Panther Tongue and Ferron Notom deltas of the Cretaceous Western Interior Seaway and a Late Ordovician proglacial delta of the Murzuq Basin in Libya. Ichnological Previous HitanalysisTop revealed traces known only from marine settings or those found across marine, brackish, and freshwater systems, with none known solely from freshwater systems. River-delivered freshets recurrently prepped a shallow marine basin, reducing delta-proximal salinities. Turnabout Ridge likely occupied a proximal-axial position relative to an Early Permian freshwater- and sedimentation-stressed, river-dominated marine deltaic system. Combined ichnology-sedimentology in Permo-Triassic strata at Lamping Peak helped identify lacustrine units, abandoned channels, and a fluctuating water table. We compare these Antarctic systems developed during a deep time icehouse-to-greenhouse transition to Arctic, paleopolar, greenhouse systems found in the Cretaceous of the North Slope of Alaska. We do this to identify facies, architectural, and ichnologic trends that help define the type of depositional systems and reveal characteristics that may be unique to high latitude depositional systems, especially those developed during greenhouse periods. These characteristics suggest that some ancient Arctic and Antarctic environments contain flashy river systems with seasonally fluctuating discharge.