ABSTRACT

The loess-paleosol proxy records from mid-latitude Asia have been instrumental in the reconstruction of regional paleoclimate evolution and its relationship with global climatic changes. The present study explores the discrete occurrence of a loess and paleosol sequence (LPS) in the Southern Zanskar Range (SZR), NW Himalaya. Stratigraphic variations in sediment texture, supplemented with geochemical, organic and magnetic proxies, indicate two broad phases of loess accretion (L-1) and paleosol formation (PS-1). The older phase of loess accretion (L-1) is dated between 2.5 ± 0.3 ka and >2.0 ka, whereas the L-2, which fully transformed into the modern soil (MS) probably deposited during the Little Ice Age (LIA) phase. The textural attributes (high sand content) of loess indicate source proximal deposition, whereas the geochemical and magnetic proxies point towards the pre-depositional weathering (in the source area). The PS-1 dated to 2189 ± 296 cal yr BP indicates improved moisture conditions, whereas the MS is assigned to post LIA warm phase. These findings provide an important step towards better understanding the sensitivity of loess accretion and paleosol formation in the SZR linked to late Holocene climate variability.

摘要

来自中纬度亚洲的黄土-古土壤代用记录有助于重建区域古气候演化及其与全球气候变化的关系。本研究探索了喜马拉雅西北地区南赞斯卡山脉 (SZR) 中黄土和古土壤层序 (LPS) 的离散出现。沉积物结构的地层变化，辅以地球化学、有机和磁性指标，表明黄土增生 (L-1) 和古土壤形成 (PS-1) 的两个主要阶段。较早的黄土增生阶段 (L-1) 的年代介于 2.5 ± 0.3 ka 和 >2.0 ka 之间，而完全转变为现代土壤 (MS) 的 L-2 可能在小冰河时代 (LIA) 阶段沉积. 黄土的结构属性（含砂量高）表明源近端沉积，而地球化学和磁性指标指向沉积前风化（在源区）。日期为 2189 ± 296 cal yr BP 的 PS-1 表明水分条件有所改善，而 MS 被分配到 LIA 后温暖阶段。这些发现为更好地理解 SZR 中黄土增生和古土壤形成与晚全新世气候变率的敏感性迈出了重要的一步。