Australia: The Land Where Time Began

A biography of the Australian continent 

Tropical Western Pacific - A 4 Ma record of Thermal Evolution - Implications for Climate Change

In this study alkenone palaeothermometry was used to reconstruct orbital resolution thermal histories over the last 4 Ma at ODP site 1143 in the western tropical Pacific. The temperature profile is characterised by a steady state of about 29o C, with fluctuations of <1oC before 2.7 Ma and a strong oscillating state from 2.7 Ma and largely as a result of cooling from up to 4oC from ~29oC during the interglacial to 26oC within the glacial intervals. A relative warm, stable surface echography during the the Early and Middle Pliocene is implied by this, in this region, that is influenced by the warm pool prior to the decrease of temperature as a response to global cooling and the formation of glacial stages that are distinct since the Late Pliocene. The smaller SST gradient between tropical eastern and western Pacific, and between the southern and northern South China Sea prior to the Pliocene, therefore indicates a warm pool, that is super sized  in the Pacific, while the larger SST gradient since that time marks progressively intensifying Walker circulation and meridional Hadley circulation, which represents the monsoon circulation in the region. On the onset of glaciation and the subsequent deglaciation during the Late Pliocene and Pleistocene may have been aided by the intensification of the Walker and Hadley circulation over the tropical Pacific.

Sources & Further reading

  1. Li, Li, Qianyu Li, Jun Tian, Pinxian Wang, Hui Wang, and Zhonghui Liu. "A 4-Ma Record of Thermal Evolution in the Tropical Western Pacific and Its Implications on Climate Change." Earth and Planetary Science Letters 309, no. 12 (9/1/ 2011): 10-20.


Author: M. H. Monroe
Last updated  13/12/2013
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