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A large body of evidence suggests that there were extensive coastal mountains along the East Asian margin during the Late Cretaceous. However, current knowledge of the paleo-mountains — the period, range, and elevation — is limited. Therefore, direct paleoaltimetry is needed to validate and evaluate the paleo-mountains in East Asia. Our study area is Jiaolai Basin, which is located at the East Asian continental margin. We estimate the paleoelevation of Jiaolai Basin during the Late Cretaceous using carbonate clumped isotope paleothermometry. After correcting for seasonal preference, latitudinal difference, and secular climate change, we conclude that the paleoelevation of Jiaolai Basin was almost certainly ≥2.0 km at ∼80 Ma. Combined with the evidence from stratigraphy, paleogeography, and paleoclimatology, our results suggest that the existence of coastal mountains along East Asia during the Late Cretaceous is likely and the model of Okhotomorsk–East Asia collision is preferred. [ABSTRACT FROM AUTHOR]

As CO 2 keeps emitting, it is urgent to project future climatic changes by quantitatively reconstructing deep time paleoclimate in high atmospheric CO 2 concentrations. However, there are still unneglected discrepancies between the terrestrial temperatures based on the climatic proxies and climate models, especially at low latitudes, which limits our interpretation of the terrestrial responses to global climate changes at low latitudes. In this study, the clumped isotope concentrations (Δ 47) and total mercury signals are analyzed for the uppermost Cretaceous-lowermost Paleogene strata in the low-latitude Nanxiong Basin, South China. After excluding the potential diagenesis by both recrystallization and solid-state reordering, our study presents an extremely high mean annual terrestrial temperature of ca. 30 °C in the low latitudes. Our result is significantly higher than the previous estimates and supports a hot and expanded tropics during the latest Cretaceous-earliest Paleocene (i.e., K-Pg boundary interval). In addition, we suggest that the hot climate was plausibly caused by Deccan Traps (DT) volcanism, although the mercury concentrations in the section show relatively low peaks during the main eruptions. We speculate that the mercury sequestration in the Nanxiong Basin may have been affected by the extremely hot and arid regional climate. • We analyze clumped isotopes and total mercury signals in low-latitude Nanxiong Basin. • The mean annual terrestrial temperature was ∼30 °C during the K-Pg boundary interval. • The low-latitude continents were extremely hot during the K-Pg boundary interval. • The mercury sequestration may had been affected by the hot and arid climate. [ABSTRACT FROM AUTHOR]