南华北早二叠世泥岩沉积与深时陆地古温度重建

地球在地质历史时期经历过多次冰室与温室气候状态间的相互转换，也发生了以雪球地球为特征的极冷和以快速升温为特征的极热气候事件。二叠纪是晚古生代冰期到中生代温室气候转换的关键时期。为深入认识二叠纪的重大气候演变，急需解决的一个科学问题是如何获取高精年代地层约束的陆地古气候信息。通过总结近年来报道的华北南部石炭—二叠纪含煤岩系的同位素年代学和泥岩风化地球化学数据，建立了基于高精年代地层格架的化学风化趋势，定量重建了华南南部在约300~286 Ma的陆地古温度变化曲线，揭示了低纬陆地古气候对高纬冰川活动和全球气候变化的响应。新建的南华北陆地古温度曲线指示了与早二叠世Asselian初期和Sakmarian晚期两次冰川消融相对应的气候变暖事件，也指示了与Asselian早期和Artinskian早期两次冰川扩张相对应的气候变冷事件。

Early Permian Mudrock Deposits and Deep-time Land Surface Temperature Reconstruction,Southern North China

Earth has experienced multiple greenhouse and icehouse periods and their inter-transformations， and extreme climatic events （e.g.， ‘snowball’ Earth， hyperthermal hothouse） in its geological past. The Permian was a critical period for the evolution from the late Paleozoic ice age to the Mesozoic greenhouse. One of the main challenges to understanding climate evolution in the Permian has been the acquisition of high-precision age-constrained quantitative data regarding successive paleoclimate changes. This work reviews geochronological and geochemical weathering data reported in recent studies of Permo-Carboniferous coal-bearing successions in southern North China. From this data， a high-precision chronostratigraphic framework is established for strata from the Benxi Formation through to the Taiyuan and Shanxi to Xiashihezi Formations， tracking chemical weathering trends in mudrock-source regions in southern North China. The weathering trends correlate very well with the glacial-deglacial sequence in high-latitude Gondwana continents. The proposed land surface MAT （mean temperature） - τ_Na （sodium depletion index） transfer function reconstructs the MAT variations for southern North China in the time interval ~300-286 Ma. The MAT curve reflects climate warming during the earliest Asselian and late Sakmarian deglaciations， and indicates climate cooling with the initiation of the Asselian and subsequent Artinskian glaciations.