Was the Oligocene-Miocene a time of fire and rain? Insights from brown coals of the southeastern Australia Gippsland Basin

Abstract

Lithotype cycles (ranging from 10 to 30. m thick) in the brown coals of the Latrobe Valley, Gippsland Basin, Australia, display well-developed lightening-upward trends. Cycle tops are characterized by abrupt and unconformable boundaries with the overlying cycle. Geological, geochemical, palynological and macrofossil evidence is consistent with a relative drying (terrestrialization) upward depositional model for the cycles.The abundance of charcoal in dark lithotypes near the cycle bases is explained by the fire-prone and highly flammable nature of the herbaceous/reed wetlands, in common with similar modern wetlands in modern Australasia, in which the dark lithotypes are suggested to have for..