Exploring the Interplay Between Paleolandslides and Glacial Activity in Upper Paleozoic Mass-Transport Diamictite Formation

Glaciation and deglaciation elevate the probability of subaquatic landslides in marine and lacustrine basins. Glacial-related factors contributing to instability include base-level changes, high sedimentation rates, meltwater floods, and seismic activity linked to glacioisostatic adjustments (GIA). These mechanisms have been studied as potential triggers for landslides at mid- to high-latitudes since the last glacial maximum. Mass-transport deposits (MTDs), a well-known result of subaquatic landslides, are common in late Paleozoic ice age (LPIA) sequences across Gondwana sub-continents, frequently appearing as diamictite. While this may suggest a climatic influence on landslides and diamictite formation during the LPIA, the cause-and-effect relationship between glaciation/deglaciation and landslides remains underexplored or speculative. This study reexamines accurately described late Paleozoic stratigraphic frameworks to decipher the conditions of MTD emplacement in relation to glaciation. Two critical questions are addressed: firstly, is there a discernible genetic link between landslide initiation and variations at the ice margin? Secondly, can mass-transport diamictites serve as indicators of a specific stage within a glacial cycle? The analysis yields two scenarios: 1) downslope resedimentation of glaciomarine sediment linked to sudden deepening caused by isostatic subsidence; 2) collapse of deltaic sediment during tectonically induced base level fall. GIA seismicity is accounted as the most likely trigger in both cases, with wave and/or tide friction due to base level fall as a contributing process in type 2 MTDs. In conclusion, ice-margin fluctuations and landslides are interconnected, but mass-transport diamictite may form at least twice within a glacial cycle, corresponding to these distinct scenarios.