Growth of the broader Indonesia archipelago as a driver of Neogene cooling
Abstract
The broader Indonesia archipelago has an out-sized influence on modern chemical weathering fluxes. The confluence of steep topography, a warm and wet tropical climate, and the presence of mafic lithologies results in high fluxes of Ca and Mg cations and associated CO 2 consumption relative to its area. Land area within the region has grown significantly since the Miocene due to the ongoing arc-continent collision between Australia and the Sunda-Banda arc system. Over the past ~15 Ma, these collisions have led to the emergence of Indonesia and New Guinea and the exhumation of large supra-subduction ophiolites and associated forearcs in the tropics. Simultaneously, cooling since the Mid-Miocene climatic optimum led to growth of the Antarctic ice sheet and onset of Northern Hemisphere glaciation. We seek to evaluate the hypothesis that the growth of the broader Indonesia archipelago played a significant role in driving this cooling trend. To do so, we have compiled paleoshoreline data and incorporated them into GEOCLIM, which couples a silicate weathering model with spatially resolved lithology to a global climate model. We find that without the increase in area of the broader Indonesia archipelago over the Neogene, atmospheric p CO 2 would have been significantly higher than present day values, remaining above the levels necessary for initiating Northern Hemisphere ice sheets.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMGP51A..08P
- Keywords:
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- 1525 Paleomagnetism applied to tectonics: regional;
- global;
- GEOMAGNETISM AND PALEOMAGNETISM;
- 1616 Climate variability;
- GLOBAL CHANGE;
- 8157 Plate motions: past;
- TECTONOPHYSICS;
- 8177 Tectonics and climatic interactions;
- TECTONOPHYSICS