Multi-proxy validation of glacial-interglacial rainfall variations in southwest Sulawesi
Multi-proxy validation of glacial-interglacial rainfall variations in southwest Sulawesi
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DOI：
10.1038/s43247-023-00873-8
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发表时间：
2023-06
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通讯作者：
A. Kimbrough;M. K. Gagan;G. Dunbar;W. Hantoro;Chuan‐Chou Shen;Hsun-Ming Hu;Hai Cheng;R. Edwards;H. Rifai;B. Suwargadi
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作者：
A. Kimbrough;M. K. Gagan;G. Dunbar;W. Hantoro;Chuan‐Chou Shen;Hsun-Ming Hu;Hai Cheng;R. Edwards;H. Rifai;B. Suwargadi
Speleothem δ18O 被广泛用作热带地区冰期-间冰期至年际尺度降雨量的代表。然而，对这一著名代理的解释的不确定性给热带古气候学带来了一个棘手的问题。在这里，我们对印度尼西亚苏拉威西岛西南部的石笋进行了配对的多代理地球化学测量，并确认了冰河时代终止期间降雨量的变化。总的来说，这些石笋跨越了大约 380,000 至 330,000 年前和 230,000 至 170,000 年前的两次冰期-间冰期过渡期。生长缓慢的石笋中的镁/钙受到穿过岩溶的水和先前方解石降水的影响，使其成为当地降雨变化的良好代表。当配对时，Mg/Ca 和 δ18O 证实了澳大利亚季风域核心从干燥冰川到湿润间冰期的显着转变。这些降雨量的变化比冰期-间冰期全球气温上升和苏拉威西岛植被的相关响应晚 4,000-7,000 年，由洞穴沉积物 δ13C 决定。
Speleothem δ18O is widely used as a proxy for rainfall amount in the tropics on glacial-interglacial to interannual scales. However, uncertainties in the interpretation of this renowned proxy pose a vexing problem in tropical paleoclimatology. Here, we present paired multi-proxy geochemical measurements for stalagmites from southwest Sulawesi, Indonesia, and confirm changes in rainfall amount across ice age terminations. Collectively, the stalagmites span two glacial-interglacial transitions from ~380,000 to 330,000 and 230,000 to 170,000 years ago. Mg/Ca in the slow-growing stalagmites is affected by water moving through the karst and prior calcite precipitation, making it a good proxy for changes in local rainfall. When paired, Mg/Ca and δ18O corroborate prominent shifts from drier glacials to wetter interglacials in the core of the Australasian monsoon domain. These shifts in rainfall occur 4,000-7,000 years later than glacial-interglacial increases in global temperature and the associated response of Sulawesi vegetation, determined by speleothem δ13C.