Abstract The Thar Desert, located in western South Asia, marks a major global biogeographic boundary and a major adaptive threshold for the eastward expansions of modern humans from Africa across Asia. Examining the framework of palaeoenvironmental change in this region, both in terms of the regional manifestation of global climate change and the physical geography of the landscape, is therefore important to understand how modern humans first engaged with this significant shift in ecology. Here, we present evidence for the oldest chronometrically dated evidence for fluvial activity within this region, located at the Nal Quarry site in the central Thar Desert. We use luminescence dating of alluvial facies to demonstrate phases of fluvial activity at the site at ∼172–174, 140–150, 79–95 and 26 thousand years ago. This result substantially extends existing evidence for fluvial activity within the Thar Desert, as well as overlapping with evidence from the southern and eastern Thar desert indicating increased fluvial activity during the Last Interglacial (Marine Isotope Stage 5), whereas the cessation of fluvial deposition at Nal Quarry is contemporaneous with the onset of activity within the Ghaggar-Hakkra channel in the northern and western Thar Desert. Critically, the phases of fluvial activity identified at Nal overlaps with substantial behavioural change across South Asia, as well as the wider expansion of modern humans across the continent. This research illuminates a dynamic fluvial landscape that existed in the late Middle Pleistocene and early Late Pleistocene at a key threshold for modern human dispersals.

中文翻译：

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塔尔沙漠中部中-晚更新世河流活动的第一个年代证据

摘要 位于南亚西部的塔尔沙漠是全球生物地理的主要边界，也是现代人类从非洲向东扩张跨越亚洲的主要适应门槛。因此，从全球气候变化的区域表现和景观的自然地理两方面检查该地区古环境变化的框架，对于了解现代人类如何首先参与这一生态学的重大转变非常重要。在这里，我们提供了该地区内河流活动最古老的计时证据，位于塔尔沙漠中部的纳尔采石场。我们使用冲积相的发光测年来证明大约 172-174、140-150、79-95 和 26000 年前该地点的河流活动阶段。这一结果大大扩展了塔尔沙漠内河流活动的现有证据，并与塔尔沙漠南部和东部的证据重叠，表明末次间冰期（海洋同位素第 5 阶段）期间河流活动增加，而纳尔的河流沉积停止采石场与塔尔沙漠北部和西部的 Ghaggar-Hakkra 海峡内的活动同时发生。至关重要的是，在 Nal 确定的河流活动阶段与整个南亚的重大行为变化以及现代人类在整个大陆的更广泛扩张重叠。这项研究阐明了存在于中更新世晚期和更新世早期的动态河流景观，这是现代人类传播的关键阈值。