Mairs Cave, Southern Australia 23-15 KYrBP Speleothem Stable Isotope Data Treble, P.C.; Baker, A.; Ayliffe, L.K.; Cohen, T.C.; Hellstrom, J.C.; Gagan, M.K.; Frisia, S.; Drysdale, R.N.; Griffiths, A.D.; Borsato, A. Treble, P.C. Baker, A. Ayliffe, L.K. Cohen, T.C. Hellstrom, J.C. Gagan, M.K. Frisia, S. Drysdale, R.N. Griffiths, A.D. Borsato, A. earth science/paleoclimate/speleothems (depth,null,null,millimeter,null,speleothems,null,null,N,null) earth science/paleoclimate/speleothems (delta 18O,calcite,null,per mil VPDB,null,speleothems,raw,continuous-flow isotope ratio mass spectrometry,N,null) earth science/paleoclimate/speleothems (age,null,null,calendar kiloyear before present,null,speleothems,null,null,N,null) earth science/paleoclimate/speleothems (delta 13C,calcite,null,per mil VPDB,null,speleothems,raw,continuous-flow isotope ratio mass spectrometry,N,null) earth science/paleoclimate/speleothems earth science/paleoclimate/speleothems (Mairs Cave>LATITUDE -32.16>LONGITUDE 138.83) Terrestrial data spanning the Last Glacial Maximum (LGM) and deglaciation from the southern Australian region are sparse and limited to discontinuous sedimentological and geomorphological records with relatively large chronological uncertainties. This dearth of records has hindered a critical assessment of the role of the Southern Hemisphere mid-latitude westerly winds on the region's climate during this time period. In this study, two precisely dated speleothem records for Mairs Cave, Flinders Ranges, are presented, providing for the first time a detailed terrestrial hydroclimatic record for the southern Australian drylands during 23-15 ka. Recharge to Mairs Cave is interpreted from the speleothem record by the activation of growth, physical flood layering, and d18O and d13C minima. Periods of lowered recharge are indicated by 18O and 13C enrichment, primarily affecting d18O, argued to be driven by evaporation of shallow soil/epikarst water in this water-limited environment. A hydrological driver is supported by calcite fabric changes. These include the presence of laminae, visible organic colloids, and occasional dissolution features, related to recharge, as well as the presence of sediment bands representing cave floor flooding. A shift to slower-growing, more compact calcite and an absence of lamination is interpreted to represent reduced recharge. The Mairs Cave record indicates that the Flinders Ranges were relatively wet during the LGM and early deglaciation, particularly over the interval 18.9-15.8 ka. This wetter phase ended abruptly with a shift to drier conditions at 15.8 ka. These findings are in agreement with the geomorphic archives for this region, as well as the timing of events in records from the broader Australasian region. The recharge phases identified in the Mairs Cave record are correlated with, but antiphase to, the position of the westerly winds interpreted from marine core MD03-2611, located 550 km south of Mairs Cave in the Murray Canyons region. The implication is that the mid-latitude westerlies are located further south during the period of enhanced recharge in the Mairs Cave record (18.9-16 ka) and conversely are located further north when greater aridity is interpreted in the speleothem record. A further comparison with speleothem records from the northern Australasian region reveals that the availability of tropical moisture is the most likely explanation driving enhanced recharge, with further amplification of recharge occurring during the early half of Heinrich Stadial 1 (HS1), possibly influenced by a more southerly displaced Intertropical Convergence Zone (ITCZ). A rapid transition to aridity at 15.8 ka is consistent with a retraction of this tropical moisture source. STUDY NOTES: Two U-series age dated speleothem records for Mairs Cave, Flinders Ranges, southern Australia. Data span 23-15 ka. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Treble, P.C. Investigator : Baker, A. Investigator : Ayliffe, L.K. Investigator : Cohen, T.C. Investigator : Hellstrom, J.C. Investigator : Gagan, M.K. Investigator : Frisia, S. Investigator : Drysdale, R.N. Investigator : Griffiths, A.D. Investigator : Borsato, A. 2017-05-10 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/22074 https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/australia/mairs2017mc-s1.txt https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/australia/mairs2017mc-s2.txt https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/australia/mairs2017mc-s1.txt https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/australia/mairs2017mc-s2.txt English https://www.ncdc.noaa.gov/paleo/study/22074 https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/australia/mairs2017mc-s1.txt https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/australia/mairs2017mc-s2.txt Pauline C. Treble, Andy Baker, Linda K. Ayliffe, Timothy J. Cohen, John C. Hellstrom, Michael K. Gagan, Silvia Frisia, Russell N. Drysdale, Alan D. Griffiths, and Andrea Borsato2017Hydroclimate of the Last Glacial Maximum and deglaciation in southern Australia's arid margin interpreted from speleothem records (23-15 ka)Climate of the Past136667-68710.5194/cp-13-667-2017http://www.clim-past.net/13/667/2017/ START YEAR: 23197 cal yr BP * END YEAR: 14845 cal yr BP 138.83 -32.16 138.83 -32.16