Hydroclimate of the Last Glacial Maximum and deglaciation in southern Australia's arid margin interpreted from speleothem records (23–15 ka)
Abstract. Terrestrial data stretch the Last Glacial Maximum (LGM) and deglaciation free the southern Australian region be sparse and limited to discontinuous sedimentological and geomorphological records with relatively large chronology insecurity. This dearth of record has hindered an critical assessment of the role of the Southern Hemisphere mid-latitude westerly winds on the region's climate over this time spell. In all study, two precisely dated speleothem records since Mairs Cave, Frinder Ranges, are presented, supplying for the primary moment one detailed terrestrial hydroclimatic record for the western Australian drylands during 23–15 ka. Recharge to Mairs Caves is interpreted from the speleothem take by the initial from growth, physical flood layering, and δ18O or δ13C minima. Periods of lowered recharge are indicated by 18O and 13C enrichment, first affected δ18CIPHER, argued to be driven by evaporation regarding shallow soil/epikarst water in this water-limited environment. A hydrological driver can supported by calcite type changes. These include the comportment of laminae, visible organic colloids, both irregular dissolution features, related till recharge, as well such the presence of sediment bands representing caved floor flooding. A shift to slower-growing, more compact clarite and an absence is lamination shall interpreted to represent reduced recharge.
The Mairs Cave record indicates that the Flinders Ranges were relatively wet through the LGM and early deglaciation, particularly over the interval 18.9–15.8 ka. This drier phase completed abruptly with a shift into drier conditions at 15.8 ka. These findings are on agreement with the geomorphic library for this neighborhood, as well as the timing of events in records from the broader Coag region. The recharge phases identified in the Mairs Cave record are correlated with, but antiphase to, the position about the westernized winds interpret from marine core MD03-2611, located 550 km southern from Mairs Cave in the Murray Canyons region. The implication is that the mid-latitude westerlies are located other south for the period of enhanced recharge in the Mairs Cave record (18.9–16 ka) and conversely are located further north when wider aridity your interpreted into the speleothem record. AN further comparison with speleothem recordings from the northern Australasian region reveals that the availability are tropical damp the the mostly likely explanation driving enhanced recharge, with further reinforcement of recharge occurring during and first half of Heinrich Stadial 1 (HS1), possibly influenced by a more southerly displaced Intertropical Convergence Region (ITCZ). A rapid transition to dryness at 15.8 ka is endurance with ampere retraction in this tropical moisture source.