Records of atmospheric carbon dioxide concentration, sea-surface temperature, and global vegetation show that Earth’s climate and environment changed significantly during the late Miocene–early Pliocene. Understanding the environmental response to insolation forcing during this transitional period may provide insights into future environmental variations resulting from the perturbation of the global carbon cycle caused by fossil fuel combustion. However, terrestrial paleoclimate records capable of resolving orbital time-scale environmental variations are mostly from Europe, especially from the region around the Mediterranean Sea. Here, we present high-resolution records of grain size, black carbon, and geochemistry from a sedimentary sequence from the northeastern margin of the Tibetan Plateau, where precipitation is mainly via the East Asian summer monsoon. We observed increases in sediment accumulation rate and black carbon mass accumulation rate at ca. 5.3 Ma, which we interpret as the result of intensified seasonal precipitation associated with the strengthening of the East Asian summer monsoon; concurrently, precessional and obliquity cycles became more prominent during the early Pliocene. Our results suggest that, in response to current and future high atmospheric carbon dioxide concentrations, changes in the East Asian summer monsoon are likely to result in increased precipitation and seasonality within its region of influence.

中文翻译：

---

青藏高原东北部贵德盆地沉积物记录的中新世-上新世边界东亚夏季风变化

大气二氧化碳浓度、海面温度和全球植被的记录表明，中新世晚期至上新世早期，地球气候和环境发生了显着变化。了解这一过渡时期的环境对日照强迫的响应可能有助于了解由于化石燃料燃烧引起的全球碳循环扰动而导致的未来环境变化。然而，能够解决轨道时间尺度环境变化的陆地古气候记录大多来自欧洲，尤其是地中海周边地区。在这里，我们展示了青藏高原东北边缘沉积序列的粒度、黑碳和地球化学的高分辨率记录，那里的降水主要来自东亚夏季风。我们观察到沉积物积累率和黑碳质量积累率在大约 20 小时内增加。5.3 Ma，我们将其解释为与东亚夏季风加强相关的季节性降水加剧的结果；同时，进动和倾斜周期在上新世早期变得更加突出。我们的研究结果表明，为了应对当前和未来的高大气二氧化碳浓度，东亚夏季风的变化可能会导致其影响区域内的降水和季节性增加。