青藏高原中部色林错矿物组合特征对晚全新世气候的响应

Late Holocene Climatical and Environmental Evolutions Inferred from Mineralogical Records in Selin Co, Central Qinghai-Tibetan Plateau

对气候敏感区青藏高原中部色林错SL-1孔岩心样品进行X射线衍射分析表明,SL-1孔岩心的矿物主要包括文石、方解石、水菱镁矿、白云石和石膏以及细碎屑物石英、白云母、绿泥石、长石等。根据岩心中矿物及其组合的意义,以1135 a BP和2900 a BP为界,可将色林错湖区5090 a BP以来的气候环境演变划分成明显不同的3个阶段,反映了色林错湖区气候总体上凉干-冷干的变化。同时,在中后期多次出现典型的冷相矿物水菱镁矿的富集沉积,揭示了色林错湖区在晚全新世期间存在多次百年尺度的冷事件。

The X-ray diffraction （XRD） analysis of the core SL-1, collected from Selin Co, the climate sensitive regions in the central Qinghai-Tibetan Plateau, reveals that the minerals in the core mainly include aragonite, calcite , hydromagnesite, dolomite, gypsum and clastic materials such as quartz, muscovite, chlorite, feldspar, etc.. Based on the mineralogy of the sediments, three climate evolution stages are identified in Selin Co area since 5090 a BP, i.e. , 5090-2900 a BP; 2900-1135 a BP; 1135-0 a BP. The climate was changed from cool dry at 5090-2900 a BP to cold dry 1135 a BP-present, with a transition during 2900-1135 a BP. Meanwhile, several cold events are also retrieved in the late Holocene, according to the accumulation of hydromagnesite in the lower part of the core.