| Summary: | The 118 m thick volcanic sequence exposed at the Ramírez Nunatak, western Jason Peninsula (65°57′S, 60°33′W), Antarctic Peninsula, is composed of a lower section where ash fall tuffs and volcanic sandstones are exposed, and an upper section dominated by rhyolithic ignimbrites. The volcaniclastic sediments of the lower section show imprints of lives assigned to Hausmannia de-ferrariisi Feruglio, which indicates a Mid-Jurassic age. The rocks from Ramírez Nunatak are correlated with Maple Formation of the same age, which is typically exposed at the surroundings of Cape Disappointment, located about 60 km northward from Jason Peninsula. These rocks form part of a siliceous large igneous province developed in Patagonia and Antarctic Peninsula in relation to the Gondwana break-up. © 2006 Asociación Geológica Argentina.
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