ABSTRACT

Kati Thanda-Lake Eyre (KT-LE) sits at the heart of Australia’s dust transport system. Satellite mapping demonstrates that the lower Channel Country/northern KT-LE represents a global dust hotspot – the largest in the Southern Hemisphere. This dust is transported widely, with two dominant plume pathways; southeast, across the Tasman Sea, South Pacific Ocean and Southern Ocean, and northwest over the Pilbara/Kimberly and Indian Ocean. Marine sedimentary records imply KT-LE has been emitting dust throughout the Quaternary and potentially longer, although dust deposits linked directly to KT-LE exist only for the past ~55 kyr. The southern section of KT-LE emits little dust today; however, palaeo-aeolian sediments outcrop in, and mantle, the southern lake margins, pointing to the possibility of major net dust deflation episodes over the last glacial cycle. The spatial extent of net-deflation episodes remains uncertain. Only one event, at 30–15 ka, is evident in both lake sedimentary records and distal dust records. Over the late Pleistocene, it remains difficult to quantity the contribution of KT-LE sediment to Australia’s dust load, although estimates suggest KT-LE generated 13% and 22% of Australia’s dust load over the last 80 and 40 ka, respectively. Modern-day/Holocene dust emissions are periodic and appear coupled to arid-humid cycles, with sediment recharge a key contributing factor. During the late Pleistocene, controls on emissions are less clear, but likely coincided with large-scale changes in moisture. Despite 80 years of dust research at KT-LE, there remains much to learn about climate–landscape interactions and dust generation in Australia’s arid heart.

摘要

Kati Thanda-Lake Eyre (KT-LE) 位于澳大利亚沙尘运输系统的核心。卫星测绘表明，较低的海峡国家/北部 KT-LE 代表了全球尘埃热点——南半球最大的尘埃热点。这种尘埃被广泛传播，有两条主要的羽流路径；东南，横跨塔斯曼海、南太平洋和南大洋，西北横跨皮尔巴拉/金伯利和印度洋。海洋沉积记录表明 KT-LE 一直在整个第四纪排放尘埃，并且可能更长时间，尽管与 KT-LE 直接相关的尘埃沉积物仅存在于过去约 55 kyr。KT-LE 南段今天几乎没有扬尘；然而，古风成沉积物在南部湖缘露头和地幔，指出在上一个冰河周期中可能发生主要的净尘埃通缩事件。净通货紧缩的空间范围仍然不确定。在湖泊沉积记录和远端尘埃记录中只有一个事件，即 30-15 ka。在更新世晚期，仍然难以量化 KT-LE 沉积物对澳大利亚沙尘负荷的贡献，尽管估计表明 KT-LE 在过去 80 和 40 ka 分别产生了澳大利亚沙尘负荷的 13% 和 22%。现代/全新世尘埃排放是周期性的，并且似乎与干旱-潮湿循环有关，沉积物补给是一个关键因素。在更新世晚期，对排放的控制不太清楚，但可能与水分的大规模变化同时发生。尽管在 KT-LE 进行了 80 年的粉尘研究，