Permian loess and dust in the Lodève basin (France) Lily
Abstract
French Carboniferous–Permian sedimentary basins record intramontane paleoequatorial climate
during Pangean assembly, ice-age collapse, and megamonsoon inception. Herein we present data
to elucidate the provenance, depositional character, and climatic signals recorded in the ~1.5 kmthick
Permian Salagou Formation (Lodève Basin, southern Massif Central, France). The Salagou
Formation predominantly consists of fine-grained red beds – Transitioning up-section from
internally massive red mudstone (with local pedogenic fea-tures) to mudstone commonly
interbedded with sedimentary structures that record intermittent shallow water. We interpret
these strata to reflect eolian transport and ultimate deposition as loess, or in shallow, ephemeral
lacustrine environments. Provenance analyses record rapid (1-17mm/year) exhumation of local
Variscan basement during early Permian syn-orogenic extension. The coarse-grained nature of
protoliths and geochemistry data that suggests minimal chemical weathering suggests that the
generation of silt occurred by physical (cold-weathering processes). This work adds to a record of
voluminous loess across low-latitude Pangea that archives a dusty atmosphere, potentially linked
to glaciated alpine terranes. Finally, analysis and modeling of rock magnetic data records
Milankovitch-scale paleoclimatic variability (predominant orbital eccentricity-scale, ~10-m- thick)
through the middle to late Cisuralian (ca. 285—275 Ma) and optimal sedimentation rates between
9.4 - 13 cm/kyr.