Late Mesozoic elevation history of the north Taihang Mountains, China: Constraints from clumped isotope geochemistry

Abstract

A series of tectonic events during the late Mesozoic, including the Yanshanian Orogeny and the Early Cretaceous tectonic extension, reshaped the tectonic regime and landscape of North China (NC). During this period, the Taihang Mountains (THM) became a prominent geomorphic and ecological separation zone, which separates NC into regions with different landforms, tectonic settings, and climatic regimes. The uplift history of the THM during the late Mesozoic is of great interest, since it is critical to constrain the geodynamic and regional climatic evolution of NC. In this study, we report the first carbonate clumped isotope thermometry (Δ47) data for paleosol carbonates from this region to constrain the paleoelevation of the north THM during the late Mesozoic. Our result indicates that the north THM was almost certainly 2.0 ± 0.8 km elevation at ca. 160 Ma associated with crust thickening and shortening. After the collapse of the eastern North China Craton (NCC), the north THM maintained high elevation at ca. 113 Ma (2.7 ± 0.7 km). The findings suggest that the present topographic features of NC may have been established in the Early Cretaceous. Finally, our study suggests elevation decrease at the end of the Early Cretaceous (ca. 110−100 Ma), which is possibly related to isostatic adjustment caused by asthenosphere upwelling and partial crustal thinning in the central NCC.

The Dynamic Evolution Model of the Chemical and Carbon Isotopic Composition of C1–3 during the Hydrocarbon Generation Process

“…The problems in the application of traditional natural gas isotope geochemistry can be attributed to the following two aspects: (a) for the current isotope analysis technology of monomer hydrocarbon, the isotopic information of the internal functional groups of the monomer hydrocarbon disappears in the process of oxidizing the target component to CO 2 or reducing it to H 2 and, accordingly, the intra-molecular isotope distribution information which can disclose the formation and evolution process of natural gas is not fully obtained [ 7 , 14 , 15 ]; (b) the dynamic evolution laws of the isotope composition of monomer hydrocarbon and corresponding mechanism during the formation and evolution process of natural gas are still in dispute [ 6 , 12 , 16 , 17 ]. Efforts to explore the intra-molecular isotope distribution of hydrocarbons, including position-specific isotope and clumped isotope analyses, have been made in the past decades [ 7 , 14 , 18 , 19 , 20 ].…”