Indonesian Throughflow drove Australian climate from humid Pliocene to arid Pleistocene

Abstract

Late Miocene to mid‐Pleistocene sedimentary proxy records reveal that northwest Australia underwent an abrupt transition from dry to humid climate conditions at 5.5 million years (Ma), likely receiving year‐round rainfall, but after ~3.3 Ma, climate shifted toward an increasingly seasonal precipitation regime. The progressive constriction of the Indonesian Throughflow likely decreased continental humidity and transferred control of northwest Australian climate from the Pacific to the Indian Ocean, leading to drier conditions punctuated by monsoonal precipitation. The northwest dust pathway and fully established seasonal and orbitally controlled precipitation were in place by ~2.4 Ma, well after the intensification of Northern Hemisphere glaciation. The transition from humid to arid conditions was driven by changes in Pacific and Indian Ocean circulation and regional atmospheric moisture transport, influenced by the emerging Maritime Continent. We conclude that the Maritime Continent is the switchboard modulating teleconnections between tropical and high‐latitude climate systems.

Deciphering the State of the Late Miocene to Early Pliocene Equatorial Pacific

“…The warm mean state, observed between 8.0–6.5 and 5.2–4.4 Ma, may be the result of a relatively unrestricted ITF following global sea level rise driven by a reduction in global ice volume between 7.7–6.7 and 5.2–4.4 Ma, as indicated by deep‐sea benthic δ 18 O and ice proximal evidence (Cook et al, ; Drury et al, , ; Hodell et al, ; McKay et al, ). Furthermore, coincident with the early Pliocene warm mean state (~5.2–4.4 Ma), the onset of humid conditions in northwest Australia at ~5.5 Ma has also been attributed to a more open ITF (Christensen et al, ).…”

Timing and Pacing of Indonesian Throughflow Restriction and Its Connection to Late Pliocene Climate Shifts

“…Modeling studies suggest that ITF variability has a major influence on ocean heat distribution (Brierley & Fedorov, ; Cane & Molnar, ; Di Nezio et al, ; Jochum et al, ), yet its contribution to the global climatic evolution is difficult to resolve due to the tectonic complexity of the Indonesian Archipelago (Brierley & Fedorov, ; Gordon et al, ; Gordon & Kamenkovich, ; Holbourn et al, ; Kuhnt et al, ; Spooner et al, ; Susanto & Song, ). Generally, ITF restriction is likely driven by two distinct mechanisms: (1) sea level‐driven restriction leading to the emergence of shelf areas restricting the ITF paths only to the deep marine troughs during glacial intervals (De Vleeschouwer et al, ; Di Nezio et al, ; Holbourn et al, ; Xu et al, , ; Zuraida et al, ); and (2) geometric reorganization of the Indonesian Gateway system caused by tectonic activity linked to the northward movement of the Australasian Plate and the related collision with the Eurasian Plate (Cane & Molnar, ; Christensen et al, ; Karas et al, ; Kuhnt et al, ; Molnar & Cronin, ; Sarnthein et al, ).…”

Toward a Robust Plio‐Pleistocene Chronostratigraphy for ODP Site 762

“…With this commentary, we highlight the issues that arise in comparative studies when all available chronostratigraphic data are not integrated or updated. We show the importance of an approach that integrates all chronostratigraphic information by comparing several Plio‐Pleistocene paleoclimate archives in the eastern Indian Ocean (Andrae et al, ; Auer et al, ; Christensen et al, ; De Vleeschouwer et al, , ; Karas et al, ; Sniderman et al, ; Stuut et al, ). These records provide insights into the climate evolution of Australia and the role of the Indonesian Throughflow between 2 and 5.5 Myr.…”