Terrestrial Material Input to the Northwest Shelf of Australia Through the Pliocene‐Pleistocene Period and Its Implications on Continental Climates

Abstract

AbstractBased on biomarkers and bulk organic carbon isotope, we reconstructed a 5‐million‐year history of terrestrial material input to the northwest shelf of Australia. Vegetational organic input continuously decreased through the Pliocene‐Pleistocene period due to decreased vegetation coverage and discharge under general aridification process. Triggered by lowered sea level and drier climates, soil input increased after ∼2.5–2.2 million years ago (Ma). Bulk terrestrial organic input demonstrates stronger variability after ∼1.7 Ma, as influenced by large‐amplitude hydrological swings on the Australian continent. Source of soils shifted between ∼1.5 and 1.2 Ma, along with presence of active dune fields. All lines of evidence together indicate a general wet climate in northwestern Australia during the early Pliocene, a continuously drying trend to the mid‐Pleistocene, and a drier phase with less vegetation coverage and expanded desert during the late Pleistocene, which is modulated by ongoing Indonesian Throughflow constriction and global atmospheric circulations.