Quantifying Ireland’s Dust Bowl: An interdisciplinary assessment of loess genesis, deposition, and dynamics in the Burren

The west coast of Ireland is currently one of the wettest environments in Europe, with year-round precipitation, high humidity, and minimal thermal seasonality maintained by a strongly North Atlantic climate. While such conditions are not conducive to dust entrainment, transport, and deposition today, we report geologic evidence from the limestone Burren uplands for a period of sustained aeolian sedimentation during the last glacial termination. Contrasting with Ireland’s till- and glacial-outwash-dominated lowlands, the Burren’s extant sediment cover comprises a homogenous mineral silt preserved in lee-side zones and karst depressions, the outer reaches of caves, and amongst drumlins. Compositionally, our sedimentologic-geochemical data confirm the quartz minerology of these silts, which are consistent in composition and morphology to similar deposits reported from the England and France previously identified as loess. We used U-Pb age profiling of zircons to establish the primary source of the loess, providing a robust test of whether Irish deposits are locally sourced or instead derived from more distal regions (e.g., central Europe-Asia); both scenarios have ramifications for atmospheric circulation patterns during glacial-interglacial transitions and abrupt climate shifts. While OSL dating of the Burren silts is ongoing, the sedimentary stratigraphy is consistent with deposition during or immediately following ice sheet retreat, which our ¹⁰Be-dating of glacial surfaces places during early Heinrich Stadial 1 (HS1). In Ireland, HS1 was also characterised by winter sea ice, extreme thermal seasonality, and relatively low sea level. At multiple Burren sites, a bi-fold stratigraphy suggests the in situ (i.e., airfall) loess is overlain by a subsequently reworked unit of silt that was remobilised during the mid-Holocene, potentially reflecting a combination of climatic and anthropogenic drivers. Thus far, the Burren loess is providing a new aeolian vantage on Europe’s Atlantic margin during the close of the last ice age and has considerable potential for exploring environmental conditions during climatic transitions.