Jurassic sedimentary provenances of the Hongshan and Huobuxun sags in the eastern segment of the northern Qaidam Basin: Basin–Mountain coupling

Abstract

The Hongshan and Huobuxun sags are located in the eastern segment of the northern Qaidam Basin, and the provenances of Jurassic deposits in the two sags are unclear. Based on the tectonic setting of the northern Qaidam Basin before the Jurassic, this paper discusses provenances of the two sags by field geological survey, analysis of detritus, and heavy minerals of the Jurassic strata. The Jurassic sedimentation in the Hongshan Sag mainly came from the Zongwulong Orogen and the Oulongbuluke and Kuerleike mountains, and the Xitie Mountain was the secondary provenance. The Jurassic deposits of the Houbuxun Sag mainly came from the Xitie and Aimunike and Dadakenwula mountains. Because of the barrier of the Zongwulong Orogen, the sources of Jurassic deposits from the South Qilian Caledonian Orogen were much fewer. Four Jurassic provenance systems of the Hongshan and Huobuxun sags are recognized through heavy mineral assemblages: Kuerleike–Zongwulong, Zongwulong–Oulongbuluke, Xitie, and Aimunike–Dadakenwula mountains provenance systems. Based on the provenance analysis of the two sags, the paper further discusses the basin–mountain system in the eastern segment of the northern Qaidam Basin during the Jurassic. The two sags were not an open connected basin as considered by some geologists but two isolated sags. The Kuerleike, Oulongbuluke, and Zongwulong mountains together constituted the northern sedimentary boundary of the Hongshan Sag, and the southern sedimentary boundary was the Xitie Mountain. The northern boundary of the Huobuxun Sag was the Xitie, Aimunike, and Dadakenwula mountains, which separated the Hongshan Sag from the Huobuxun Sag, resulting in the two sags to evolve independently into the faulted basins during the Jurassic.

Jurassic sediments geochemical constraints on provenance, weathering process, and palaeoclimate variation of the north margin of Qaidam Basin, north‐eastern Tibetan Plateau

“…Provenance interpretations of Jurassic sediments can provide data for surrounding mountains tectonic evolution of Qaidam Basin, thus enhancing the understanding of the uplift events in north‐eastern Tibetan Plateau. In recent years, research based on petrography (Feng et al, ; Tang et al, ; Wu et al, ), geochemistry (Cao et al, ; Jian et al, ), and heavy mineral (Shu et al, ) were carried out, but the detailed and systematic provenance studies of the sediments are relatively scarce. Dameigou profile sandstone detrital zircon geochronological studies were reported both by Yu et al () and Qian et al (), but the results indicate different Jurassic primary source areas.…”

Central China Orogen along the Silk Road (Part I): Tectono‐thermal evolution and its links

“…In the paper by Peng et al (), the focus of the study was on Early Paleozoic arc magmatism and metamorphism in the northern Qilian Block. The final three papers in this region by H. Feng et al (); Shu et al (); and Z. Tang et al () all concentrate on aspects of Jurassic basin sedimentation characteristics, and provenance in the northern Qaidam Block.…”