High-precision U-Pb age constraints on the Permian floral turnovers, paleoclimate change, and tectonics of the North China block
High-precision U-Pb age constraints on the Permian floral turnovers, paleoclimate change, and tectonics of the North China block
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DOI：
10.1130/g48051.1
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发表时间：
2021-02
期刊：
影响因子：
5.8
通讯作者：
Qiong Wu;J. Ramezani;Hua Zhang;Jun Wang;F. Zeng;Yi‐chun Zhang;Feng Liu;Jun Chen;Yaoping Cai;Z. Hou;Chaohui Liu;Wan Yang;C. Henderson;S. Shen
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作者：
Qiong Wu;J. Ramezani;Hua Zhang;Jun Wang;F. Zeng;Yi‐chun Zhang;Feng Liu;Jun Chen;Yaoping Cai;Z. Hou;Chaohui Liu;Wan Yang;C. Henderson;S. Shen
华北陆块二叠纪海陆交互系统为研究晚古生代冰期（LPIA）后从冰库到温室的关键过渡期北方温带生态系统的演化提供了一个独特的窗口。尽管对其丰富的油气储量和气候敏感的化石植物群进行了许多研究，但不确定的时间限制和相关性阻碍了对华北地块地质，生物和气候变化记录的全面了解。基于高精度U-Pb化学剥蚀-同位素稀释-热电离质谱（CA-ID-TIMS）年代学方法，对华北晚石炭-二叠纪沉积序列中的凝灰岩进行了年代地层学研究。结果表明，华北陆块早二叠世（Cisuralian）大陆红层的优势、气候的干旱化、煤和热带特有植物群的消失，都在进行之中，比以往认为的要早得多。近20米。华北陆块北方存在一个从昆古早世到瓜达卢普中期（或更晚）的间断，它与古亚洲洋的闭合和俯冲及其相关的构造汇聚有着密切的时空联系。这种长期的间断是伴随着高度多样性和丰富的华夏植物群的显着损失和广泛的入侵下，在华北地块的干旱气候条件下，单调的安加拉植物群。欧亚大陆和中国北方的植物和气候变化的历史相似性表明，除了区域构造控制和大陆运动，广泛的火山活动在西苏拉可能发挥了重要作用，在全球变暖和干旱化的后果LPIA。
The Permian marine-terrestrial system of the North China block provides an exceptional window into the evolution of northern temperate ecosystems during the critical transition from icehouse to greenhouse following the late Paleozoic ice age (LPIA). Despite many studies on its rich hydrocarbon reserves and climate-sensitive fossil flora, uncertain temporal constraints and correlations have hampered a thorough understanding of the records of geologic, biologic, and climatic change from the North China block. We present a new chronostratigraphy based on high-precision U-Pb chemical abrasion–isotope dilution–thermal ionization mass spectrometry (CA-ID-TIMS) geochronology of tuffs from a near-complete latest Carboniferous–Permian succession in North China. The results indicate that the predominance of continental red beds, climate aridification, and the disappearance of coals and characteristic tropical flora were well under way during the Cisuralian (Early Permian) in the North China block, significantly earlier than previously thought. A nearly 20 m.y. hiatus spanning the early Kungurian to the mid-Guadalupian (or later) is revealed in the northern North China block to have close temporal and spatial associations with the closure and/or subduction of the Paleo-Asian Ocean and its related tectonic convergence. This long hiatus was concomitant with the prominent loss of the highly diverse and abundant Cathaysian floras and the widespread invasion of the monotonous Angaran floras under arid climate conditions in the North China block. Similarities in the floral and climate shift histories between Euramerica and North China suggest that aside from the regional tectonic controls and continental movement, extensive volcanism during the Cisuralian may have played a major role in the global warming and aridification in the aftermath of the LPIA.