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During the Cretaceous, there were two factors that had important influences on the East Asian climate, the East Asian coastal mountains and Earth's orbital cycling. An important question is how the coastal mountains modulated the variability of East Asian climate over orbital timescales. Here, we perform simulations with the coastal mountains of 0, 2, and 4 km high and three orbital configurations to answer the question. Our results show that a mountain range at the East Asian coast can amplify the impacts of orbital forcing on East Asian climate. Specifically, precipitation over the Songliao Basin in Northeastern China has significant changes as the coastal mountain range is about 4 km high. Combining our simulation results with orbitally‐controlled sedimentary deposits from the Songliao Basin, we conclude that the altitude of the coastal mountain range was very likely higher than 2 km in the Late Cretaceous. Plain Language Summary: Tectonic events and solar insolation are the two important factors impacting variations of the climate system in the geological past. Regional climate responses to variations in the radiation from the sun over 104–105 years were often magnified or dampened by tectonic events. Cretaceous sedimentary records in East Asia suggest that East Asian climate was influenced by the solar insolation. Geological evidence showed that a mountain range existed along the East Asian coast then. Would this mountain range modulate impacts of solar insolation on East Asian climate? Our modeling results show that the influence of solar insolation on East Asian climate can be amplified by the coastal mountain range, depending on the mountain elevation. When the coastal mountain range is ∼2 km high, the amplification effects become significant. When its altitude reaches ∼4 km, the response of East Asian climate to solar insolation is considerably strengthened, and such a condition is supported by the rhythm induced by the climate variation due to solar insolation archived in the Cretaceous strata in the Songliao Basin. Thus, we speculate that the East Asian coastal mountains might have reached an altitude more than 2 km in the Late Cretaceous. Key Points: East Asian climate was sensitive to orbital forcing in the Late CretaceousEast Asian coastal mountains amplified orbital forcing on East Asian climate variabilityEast Asian coastal mountains were likely higher than 2 km in the Late Cretaceous [ABSTRACT FROM AUTHOR]

Geochemical studies of marine sediments indicate that most Oceanic Anoxic Events (OAEs) appear coincident with Large Igneous Province (LIP) volcanism. OAE 1d records peculiar paleoceanographic changes and global carbon cycle perturbations, however, its association with volcanism has not yet been supported by robust geochemical evidence. To examine the potential role of volcanism we investigated the mercury (Hg) concentration and isotopic record of OAE 1d interval at the Youxia section, southern Tibet. The interval prior to OAE 1d is marked by a combined positive Δ199Hg and Hg content shift, which suggests a volcanic Hg source. These findings are consistence with a prominent increase in sea surface temperatures and atmospheric CO2 before OAE 1d. We suggest that eruption of the central portion of the Kerguelen LIP may have been the main source of the Hg anomaly and resulted in global environment perturbations that drove the onset of the anoxia event. Plain Language Summary: The mid‐Cretaceous is characterized by globally high temperature, sea‐level, and atmospheric CO2. Recurrent volcanism considered to be the main driver of the Cretaceous hothouse, led also to frequent ocean anoxia events and global carbon cycle perturbations. One such perturbation is oceanic anoxic event (OAE) 1d; however, unlike other OAEs its association with volcanism has not yet been proven. Mercury (Hg) is mainly sourced from volcanism, and enhanced volcanic activity is recorded as spikes in Hg concentration in marine sediments. We used multiple geochemical proxies, especially Hg chemical analyses, to examine the potential role of volcanism in the OAE 1d event. Based on the data, we find a volcanic derived Hg anomaly occurred just prior to the onset of the OAE. These findings are in agreement with a prominent increase in sea surface temperatures and atmospheric CO2 at the same period. We suggest then that the eruption of the central portion of Kerguelen LIP resulted in global environment perturbations that drove the onset of the OAE 1d. Key Points: The first mercury (Hg) concentration and isotope record of Oceanic Anoxic Event (OAE) 1d, from southern TibetHg anomaly prior to the onset of OAE 1d is derived from a volcanic sourceCentral Kerguelen LIP volcanism may have triggered OAE 1d global climate change [ABSTRACT FROM AUTHOR]

The evolution of Cenozoic climate patterns in Asia has been linked to uplift of the Tibetan Plateau (TP), retreat of the Paratethys Sea, and global cooling. However, less attention has been placed on the latitudinal change of the TP. Here we report new climate modeling to explore how modern climate changes as a function of topographic growth and spatial migration of the TP. Our results show that the northward displacement of the uplifted proto‐TP within the subtropics can significantly affect the wind and precipitation pattern over East‐Central Asia. By compiling proxy‐based climatic records, paleolatitudinal and paleoelevational evolution models of the proto‐TP, and in comparison with previous modeling under a global paleogeography, we suggest that the northward migration of the proto‐TP in the Paleogene could have intensified the aridity in Central Asia, but its influence on East Asian precipitation and monsoonal circulation could be dependent on the paleogeography and other boundary conditions. Plain Language Summary: The evolution of the Asian monsoons and aridification of Asia's interior are thought to be driven by Tibetan‐Himalayan uplift. Recent geological observations suggest that the uplifted proto‐Tibetan Plateau (proto‐TP) migrated northward in the subtropics since the early Eocene and reached its present position by the latest Oligocene. We therefore simulated the effects of this process on East‐Central Asian climate. Our climate modeling shows the northward migration of the high proto‐TP from 21–29°N to 29–37°N can significantly change the present‐day wind and precipitation patterns over East‐Central Asia. Especially, Central Asia become drier because of the displacement of the anomalous dry belt caused by large‐scale atmospheric subsidence. We further suggest that forcing by the paleolatitudinal migration of the high proto‐TP within the subtropics from the Eocene to the earliest Miocene could have drove the Central Asian paleoclimate to dryer conditions, but migration might not be the sole parameter that governed the East Asian monsoon during the Paleogene. Key Points: The high proto‐Tibetan Plateau migrating northward can notably influence the modern East‐Central Asian climate systemCentral Asian aridification increased with the northward migration of the proto‐Tibetan Plateau in the PaleogeneThe impact of Paleogene proto‐Tibetan Plateau migration on East Asian climate could be dependent on boundary conditions [ABSTRACT FROM AUTHOR]