A 60 000‐year record of environmental change for the Wet Tropics of north‐eastern Australia based on the ODP 820 marine core

Abstract

Palynomorphs from the ODP Site 820 marine core have provided a detailed record of terrestrial environmental responses to glacial–interglacial forcing over the last 250 000 years in the Australian Wet Tropics. The development of an accurate geochronological framework for this key sequence has proved challenging. Consequently, different dominant forcing mechanism(s) have been proposed to drive environmental change in the low latitudes. A new chronology for the last 60 000 years, based on accelerator mass spectrometry radiocarbon (14C) dates of pollen concentrate material and the existing Marine Isotope Stage boundaries (MIS 4 to 1) has been produced. This new chronology provides a robust geochronological framework for interpreting environmental records across the region. In particular, our age model helps to resolve several debates concerning the timing of climatic changes and their impacts on both the marine and the terrestrial systems, as well as possible human arrival and associated impacts on the region's ecosystems. Our findings suggest 14C dating of terrestrial pollen concentrate in marine sediments is a valuable tool for resolving major chronological uncertainties in potentially diagenetically altered marine CaCO3 sediments and should play a role in future multi‐dating strategies. Copyright © 2017 John Wiley & Sons, Ltd.

Late Quaternary records and chronology of environmental change in the Southern Hemisphere – a contribution to SHAPE

“…Their results support previous interpretations for a more arid LGM followed by steadily increasing precipitation through to the onset of the Holocene. Interestingly, Moss et al (2017) conclude a similar LGM and Holocene climate scenario for north-east Queensland.…”

“…The pollen-climate reconstructions, including maximum LGM temperature depression of 6-8˚C, appear to be tied to shifts in the westerlies and are consistent with the model of ocean-atmosphere CO 2 flux modulated by their latitudinal migration. The same time interval is covered by the pollen record from ODP820, offshore from north-east Queensland presented by Moss et al (2017) Using accelerator mass spectrometry radiocarbon ages on pollen concentrates, they were able to develop a far more convincing chronology than was previously achieved by radiocarbon dating foraminifera and in so doing were able to shed important light on climate changes and human-environment interaction in the region.…”

“…The same time interval is covered by the pollen record from ODP820, offshore from north‐east Queensland presented by Moss et al . () Using accelerator mass spectrometry radiocarbon ages on pollen concentrates, they were able to develop a far more convincing chronology than was previously achieved by radiocarbon dating foraminifera and in so doing were able to shed important light on climate changes and human–environment interaction in the region.…”

“…Interestingly, Moss et al . () conclude a similar LGM and Holocene climate scenario for north‐east Queensland.…”

Environmental changes in the north‐east Sunda region over the last 40 000 years

“…The climate was cold and dry (Sun et al ., ). The extensive shelves on the south‐east Asia–Sahul Shelf and north‐eastern Australia were covered by grass and shrub vegetation, indicative of a dry environment (Kershaw, ; Kershaw et al ., ; Moss et al ., ; van der Kaars et al ., ) during the LGM. High grass values were also found during the LGM in Singapore and Sumba, an island in eastern Indonesia (Partin et al ., ; DiNezio and Tierney, ), and in a series of exposures in the Great Cave of Niah, Sarawak, Malaysian Borneo, as indicated by taxa characteristic of open environments or highly disturbed open forests (Hunt et al ., ).…”