Ice-crystal traces imply ephemeral freezing in early Permian equatorial Pangea
نویسندگان
چکیده
Abstract Delicate impressions in lacustrine strata of the lower Permian (lower Cisuralian) Usclas Formation record ephemeral freezing equatorial Pangea. These sediments accumulated paleoequatorial and intramontane Lodève Basin (southern Massif Central, France) during peak icehouse conditions Late Paleozoic Ice Age. Experimental replication these features supports interpretation that they are ice-crystal molds. Evidence for films ice marginal-lacustrine sediment at such low latitudes inferred to moderate altitudes (1–2 km) calls a reevaluation climate eastern Ephemeral implies either cold tropical temperatures (~5 °C cooler than Last Glacial Maximum) and/or lapse rates exceeded those Maximum. Extreme continentality would have amplified seasonality, albeit climatic forcing(s) necessary promoted Pangea remain enigmatic.
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ژورنال
عنوان ژورنال: Geology
سال: 2021
ISSN: ['0091-7613', '1943-2682']
DOI: https://doi.org/10.1130/g49011.1