Paleomagnetic chronology and paleoenvironmental records from drill cores from the Hetao Basin and their implications for the formation of the Hobq Desert and the Yellow River

Abstract

Reconstructing the Cenozoic environmental history of Hetao Basin, in the northern part of the Ordos Plateau in North China, is important not only for revealing the evolution of the Yellow River, but also for understanding the formation of the Hobq Desert. Here we present the stratigraphic framework of drill core DR01 with length of 2503.18 m, and the results of magnetostratigraphic and ESR dating and multi-proxy analyses of drill core WEDP05 with length of 274.60 m, from the Hetao Basin. The magnetostratigraphic and ESR results indicate that core WEDP05 spans the last ~1.68 Ma. Stratigraphic sequence of core DR01 indicates that the Hetao area was uplifted and eroded during the early Cenozoic, before subsiding to form a sedimentary basin. Subsequently, the basin was a fluvio-lacustrine environment during the Pliocene and then experienced alternating desert and fluvio-lacustrine conditions during the Quaternary. Sedimentary facies and multi environmental-proxy analyses of core WEDP05 indicate that the basin was occupied by a fluvio-lacustrine system during the following intervals: ~1.47-~1.30 Ma, ~1.17-~1.07 Ma, ~0.68-~0.60 Ma and from ~0.47 Ma to the last interglacial; and that a desert environment developed during the lake regression phases of ~1.30-~1.17 Ma, ~1.07-~0.68 Ma and ~0.60-~0.47 Ma. The presence of aeolian sand at the base of core WEDP05 suggests that the origin of the Hobq Desert can be traced back to the early Pleistocene, and resulted from the erosion and transportation of exposed fluvio-lacustrine sediments by near-surface winds associated with the Asian winter monsoon. A large river channel in the Hetao Basin may have existed as early as the Pliocene, which was 3 occupied by the Yellow River when its upper reaches formed by at least ~1.6 Ma. Subsequently, at least since ~1.2 Ma, the Yellow River formed its drainage system around the Hetao Basin and controlled the paleoenvironment evolution of the basin.

Phylogeography and conservation genetics of the endangered Tugarinovia mongolica (Asteraceae) from Inner Mongolia, Northwest China

“…mongolica . In addition, the divergence time of two geographic groups (Fig 4) is consistent with the formation of the Hobq Desert [56, 57], which, as a geographical barrier, may have blocked the genetic flow between the northern and southern groups. Previous studies have shown that the desert, as a geographical barrier, promotes the allopatric divergence of species [4].…”

Angular Unconformity of the Late Quaternary Strata in the Hetao Basin, North of the Ordos Block (West China): Timing and Its Tectonic Implications

“…Furthermore, the paleo-seismic studies revealed multiple ancient seismic events (Ran et al, 2003;. Drilling data in the Hetao Basin reveals that the maximum deposition thickness of the basin since the Quaternary is >2400 m, and the conversion of river-lacustrine deposition to aeolian deposition has occurred in multiple stages (Li et al, 2017). Previous authors based on thermochronology, regional stratigraphy, and structural geomorphology have shown that the mountains to the north of the Hetao Basin and the subsiding basins have experienced multiple periods of tectonic uplift, erosion and flattening.…”

“…In this study, we focused on the Hetao Rifted Basin to the north of the Ordos Block. As it acts as a paleolake during the last glacial-interglacial period (Li et al, 2007;Jia et al, 2016;Li et al, 2017;Cai et al, 2018), widely distributed lacustrine sediments of the Hetao paleolake could provide a sedimentary archive for recording the history of the evolution of the Hetao paleolake and its tectonics activity (Li et al, 2017;Cai et al, 2018;Yang et al, 2018, Yang et al, 2020. Based on a detailed investigation of the piedmont faults in the northern margin of the Hetao Basin, we documented a series of Late Quaternary angular unconformities within four sedimentary sections, including Hazigai, Haolaigou, Bianqianghao, and Huhesala.…”

Impact of sedimentation history for As distribution in Late Pleistocene-Holocene sediments in the Hetao Basin, China

“…Then, it started to flow out of the basin at the beginning of late Pleistocene. As a consequence, the paleolake started to shrink the size until it completely disappeared (Li et al 2017;Yang et al 2018).…”