Rapid interhemispheric climate links via the Australasian monsoon during the last deglaciation

Abstract

International audienceRecent studies have proposed that millennial-scale reorganization of the ocean-atmosphere circulation drives increased upwelling in the Southern Ocean, leading to rising atmospheric carbon dioxide levels and ice age terminations. Southward migration of the global monsoon is thought to link the hemispheres during deglaciation, but vital evidence from the southern sector of the vast Australasian monsoon system is yet to emerge. Here we present a 230thorium-dated stalagmite oxygen isotope record of millennial-scale changes in Australian- Indonesian monsoon rainfall over the last 31,000 years. The record shows that abrupt southward shifts of the Australian-Indonesian monsoon were synchronous with North Atlantic cold intervals 17,600-11,500 years ago. The most prominent southward shift occurred in lock-step with Heinrich Stadial 1 (17,600-14,600 years ago), and rising atmospheric carbon dioxide. Our findings show that millennial-scale climate change was transmitted rapidly across Australasia and lend support to the idea that the 3,000-year-long Heinrich 1 interval could have been critical in driving the last deglaciation. DOI: 10.1038/ncomms3908

Southern Hemisphere control on Australian monsoon variability during the late deglaciation and Holocene

“…In contrast, there is evidence for sustained precipitation in the Flores Sea area during HS1 from speleothem d 18 O (ref. 17) and from 232 Th flux records as a proxy for detrital riverine input 18 . However, our records from the Timor Strait do not indicate substantially increased precipitation at this time (Fig.…”

Millennial meridional dynamics of the Indo-Pacific Warm Pool during the last termination

“…Wang et al, 2001;Lea et al, 2003;X. Wang et al, 2007;Griffiths et al, 2009;Shakun and Carlson, 2010;Mohtadi et al, 2011;Meckler et al, 2012;Ayliffe et al, 2013;Carolin et al, 2013;Gibbons et al, 2014;McGee et al, 2014, Fig. 6).…”

“…Lynch's crater records from northeastern Australia at 17 • S (Muller et al, 2008) show strong Australian summer monsoonal conditions. Stalagmite δ 18 O records at Flores Island (8 • S) also feature intense precipitation during H1 and the YD (Griffiths et al, 2009;Ayliffe et al, 2013). However, marine and stalagmite δ 18 O evidence reveal conditions of reduced precipitation and increased salinity in the northern IPWP, north of 8-10 • S, including the South China Sea (12 • N; Steinke et al, 2006), Sulu Sea (8 • N; Rosenthal et al, 2003), Philippine Sea (6 • N; Stott et al, 2002;Boillet et al, 2011), Java Island (8 • S; Mohtadi et al, 2011), Solomon Sea (9 • S; this study), and Borneo island (4 • N; Meckler et al, 2012;Carolin et al, 2013) (Fig.…”

Hydroclimate of the Last Glacial Maximum and deglaciation in southern Australia's arid margin interpreted from speleothem records (23–15 ka)

“…De Deckker et al, 2012). Speleothem records from Liang Luar, Flores (Ayliffe et al, 2013) (e); Ball Gown Cave, Western Australia (Denniston et al, 2013a) (f); and C126 Cave in Cape Range, also in Western Australia (Denniston et al, 2013b) (g). Reconstructed salinity from marine care SO189-39KL from the northern Mentawai Basin, Indonesia (h).…”

“…1a). We also draw on a comparison of our data with independent evidence for the location of the westerly winds, inferred from the foraminifer-derived proxy record of the STF from marine core MD03-2611(De Deckker et al, 2012 and tropical speleothems from northern Australasia (Ayliffe et al, 2013;Denniston et al, 2013a, b) as well as other archives of climatic change relevant to the southern Australian region.…”