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This paper addresses the Phanerozoic tectonic evolution of the western Tarim Basin based on an integrated stratigraphic, structural and tectonic analysis. P-wave velocity data show that the basin has a stable and rigid basement. The western Tarim Basin experienced a complex tectonic evolutionary history, and this evolution can be divided into six stages: Neoproterozoic to Early Ordovician, Middle Ordovician to Middle Devonian, Late Devonian to Permian, Triassic, Jurassic to Cretaceous and Paleogene to Quaternary. The western Tarim Basin was a rift basin in the Neoproterozoic to Early Ordovician. From the Middle Ordovician to Middle Devonian, the basin consisted of a flexural depression in the south and a depression that changed from a rift depression to a flexural depression in the north during each period, i.e., the Middle–Late Ordovician and the Silurian to Middle Devonian. During the Late Devonian to Permian, the basin was a depression basin early and then changed into a flexural basin late in each period, i.e., the Late Devonian to Carboniferous and the Permian. In the Triassic, the basin was a foreland basin, and from the Jurassic to Cretaceous, it was a downwarped basin. After the Paleogene, the basin became a rejuvenated foreland basin. Based on two cross sections, we conclude that the extension and shortening in the profile reflect the tectonic evolution of the Tarim Basin. The Tarim Basin has become a composite and superimposed sedimentary basin because of its long-term and complicated tectonic evolutionary history, highly rigid and stable basement and large size. [ABSTRACT FROM AUTHOR]

The Holocene hydrological regime on the Heixiazi Island is critical for understanding the evolution of the East Asian summer monsoon (EASM) for the island's climate-sensitive location on the northern fringe of the EASM domain. In this paper, a marsh depression on the central island was selected to reconstruct the locally hydrological variation and to discuss its indications for the Holocene EASM evolution. This work is based on multi-proxy (magnetic susceptibility, grain size, loss-on-ignition, and carbonate content) analyses of 22 modern sedimentary samples with a water-level gradient of 0–66 cm and 100 cored sedimentary samples covering last ~ 9.0 ka BP. The proxies' hydrological significance was previously interpreted by the 22 modern samples using linear regression equations to construct their relationships to water-level changes. Among these proxies, the magnetic susceptibility, carbonate content, as well as the Md and sand fraction of grain size exhibit high-level relationships against the water-level changes with R2 > 0.6. Thus, these four proxies' linear-regression equations were selected and used on the 100 cored samples, and the Holocene water-level changes in the studied depression were quantitatively reconstructed. It shows that two relatively high water-level stages with strengthened EASM occurred during 8.0–4.5 ka BP and 3.0–1.4 ka BP, which were alternated by three low water-level stages with declined EASM during ~ 9.0–8.0 ka BP, 4.5–3.0 ka BP, and 1.4–0 ka BP, respectively. Among these fluctuations, the highest water-level stage with most strengthened EASM which is defined as the Holocene Monsoon Maximum occurred during 6.4–4.5 ka BP. Such a new evolution pattern of the EASM can be further supported by a large variety of records from monsoon-margin regions. We suggest the Holocene EASM evolution was generally associated with the thermal conditions in both the inner Eurasia landmass and the West Pacific Ocean, with an exception of the weak EASM before 8.0 ka BP due to the enhanced Siberia High with the dominance of the Eurasia ice sheet in the early Holocene. [ABSTRACT FROM AUTHOR]