Ice-crystal traces imply ephemeral freezing in early Permian equatorial Pangea

Lily S. Pfeifer, Brooke A. Birkett, Jean Van Den Driessche, Stéphane Pochat, Gerilyn S. Soreghan

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

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

Original languageEnglish (US)
Pages (from-to)1397-1401
Number of pages5
JournalGeology
Volume49
Issue number11
DOIs
StatePublished - Nov 2021
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Geology

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