%0 Journal Article
%A Retallack, G.J.
%A Alonso Zarza, Ana María
%T Middle Triassic paleosols and paleoclimate of Antarctica
%D 1998
%@ 1527-1404
%U https://hdl.handle.net/20.500.14352/59041
%X The Lashly Formation in the Allan Hills of southern VictoriaLand, Antarctica, is now at a latitude of 768S and during theMiddle Triassic was at least 708S. The combined evidence of fossil rootsand soils indicates a paleoclimate unusual for such a high latitude.Temperate paleotemperature is indicated by roots, logs, and leaves ofwoody plants and the degree of chemical weathering and clay formationwithin the paleosols. Paleosols of the Lashly Formation are morelike soils of southern Sweden than those of either Finland or southernEurope. Silt infiltration structures around root traces and in crackswithin the paleosols are evidence for a seasonally snowy climate, butthere is no evidence of ice wedges or other permafrost features in thepaleosols. Other evidence of climatic seasonality includes well-definedgrowth rings in fossil wood, and abscission scars at the base of fossilleaves. Diverse broadleaf plants, and noncalcareous paleosols, indicatea humid climate with mean annual precipitation of about 1200 mm.Such a wet climate is anomalous for the interior of the supercontinentof Pangea, and such a warm and mildly seasonal climate is anomalousfor such high latitudes. This paleoclimatic anomaly may be a lingeringeffect of global greenhouse initiated at the Permian–Triassic boundary.Paleoclimatic variables calculated here may be useful for recalibratingglobal paleoclimatic models for the middle Triassic
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