Source:Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 490
Author(s): Stacey C. Priestley, Karl E. Karlstrom, Andrew J. Love, Laura J. Crossey, Victor J. Polyak, Yemane Asmerom, Karina T. Meredith, Ryan Crow, Mark N. Keppel, Marie A. Habermehl
Travertine deposits precipitated by groundwater discharging from the Great Artesian Basin (GAB) are widespread in central Australia and have the potential to provide a record of palaeohydrogeology and palaeoclimate. The GAB is one of the largest artesian basins in the world and a relationship between travertine deposits and recharge sites has potential importance regarding the time and position of past climate events, given that the travertines growth forms from precipitation discharge. We sampled numerous travertine sites in the southwest section of the GAB as a first approach to test this relationship. U-series dating of the travertine deposits reveal that spring discharge has likely been episodic for the last several hundred thousand years. Spring travertine deposition occurred episodically around 465±50ka, 370±20ka, 335±15ka, 285–240ka, 185±10ka, 160–150ka, 110–100ka and during the past 30ka. The periodicity of travertine ages observed with simultaneous deposition at multiple locations, argues for regional palaeohydrologic controls. Comparison of the travertine deposit ages with climate proxies in Australia shows that elevated travertine deposition rates are synchronous with wet periods in both central and southern Australia. Due to the large size of the GAB and that the recharge zones extend over multiple climatic regions of Australia, the times of travertine deposition are interpreted to represent times of high rainfall regionally. This study shows that the travertine deposits of central Australia provide a datable archive of past climate and hydrogeology of importance for understanding the groundwater evolution of the Great Artesian Basin, and that further more comprehensive studies are warranted.
from # All Medicine by Alexandros G. Sfakianakis via alkiviadis.1961 on Inoreader http://ift.tt/2Ayly1J
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