Late Quaternary Environment Evolution Of The Situation Of The Drilling Cores In The Ulan Buh Desert Southern

The Ulan Buh Desert(UBD), in southwestern Inner Mongolia, is one of the main dune fields and dust source areas in northern China, and is one of the main dust source areas. In the southern UBD, consisting primarily of high pyramidal and complex sand dunes, and consisting primarily of fixed dunes in the north. For the environmental changes of Tall Sand Mountain in Ulan Buh Desert southern, desert environment change and desert formation evolution process is unclear, due to a lack of depositional records and environmental proxy index analyses. In this study, quartz and K-feldspar optical dating, environmental proxy indexes of grain size, loss on ignition, pollen, and ostracod analysis were employed to supplement the sediment record of a 120.5 m drill core,WL12ZK-1, from the southern UBD. Quartz Optical Stimulated Luminescence(OSL) and K-feldspar multi-elevated-temperature post-IR IRSL(Met-pIRIR) dating technologies were employed to provide a chronology for this sequence. Internal checks of the quartz OSL dating indicate that the quartz single-aliquot regenerative-dose protocol is appropriate for equivalent dose determination and that the quartz ages younger than 60 ka are acceptable. The reliability of the K-feldspar ages is confirmed by both internal checks and an age-temperature plot. Combined with the desert north of the existing WL10ZK-1 and WL10ZK-2 drill core deposit before recording,arid environment Ulan Buh Desert in southern drill core WL12ZK-1 paleo environmental proxies and age results show that the UBD desert areas drought environment has been formed in middle and late pleistocene. The combined stratigraphy and chronology indicate a sand desert landscape developed in the southern UBD at least ~232 ka ago, and that a paleolake was present beginning sometime before ~155 ka and lasting until ~87 ka, with several possible lake level fluctuations.An arid environment appeared again after ~87 ka, and there is no evidence of a large stable lake in the UBD at any time thereafter. Sand dune deposition and a very arid desert environment were present throughout the last glacial period and lasted into the early Holocene. During the Holocene these arid conditions were interrupted by minor wetland intervals. Deserts in southern Inner Mongolia formed at least since the middle Pleistocene, expanded during the last glaciation and into the earlyHolocene and again after ~2 ka. We suggest that a combination of tectonic activity and climate change may be responsible for desert formation and environmental changes in southern Inner Mongolia since the middle Pleistocene, with additional human influence exacerbating these conditions in the late Holocene.