Deep-water facies sections have advantages of recording complete information across the Permian-Triassic boundary(PTB). Here we present a detailed study on the conodont biostratigraphy and carbon isotope profile range...Deep-water facies sections have advantages of recording complete information across the Permian-Triassic boundary(PTB). Here we present a detailed study on the conodont biostratigraphy and carbon isotope profile ranges from the Wuchiapingian-Changhsingian boundary(WCB) to the PTB of two deep-water facies sections at Zhuqiao and Shiligou in the Middle Yangtze region, western Hubei, South China. Fifteen species and three genera are identified. Eight conodont zones are recognized which in ascending order are the Clarkina orientalis, C. wangi, C. subcarinata, C. changxingensis, C. yini, C. meishanensis, Hindeodus parvus and Isarcicella isarcica zones. The onset of deposition of the deep-water siliceous strata of Dalong Formation in western Hubei began in the Late Wuchiapingian and persisted to the Late Changhsingian. Carbon isotope negative excursions occur near both the WCB and PTB in both sections. The WCB δ13 Ccarb negative excursion is in the C. orientalis and C. wangi zones. The PTB δ13 Ccarb negative excursion began in the C. yini Zone and extended to the I. isarcica Zone. The absence of several Changhsingian zones may indicate the difficulty of extracting conodonts from siliceous strata or the presence of an intra-Changhsingian hiatus.展开更多
在末次冰期发生的6次海因里希事件(Heinrich事件,简称H事件)中,H6事件发生年代最早,对其研究较少,利用高分辨率石笋记录研究H6事件期间的气候环境变化,有助于理解高低纬度气候变化对H事件的响应过程。本文基于重庆市金佛洞石笋JF2017铀...在末次冰期发生的6次海因里希事件(Heinrich事件,简称H事件)中,H6事件发生年代最早,对其研究较少,利用高分辨率石笋记录研究H6事件期间的气候环境变化,有助于理解高低纬度气候变化对H事件的响应过程。本文基于重庆市金佛洞石笋JF2017铀系测年数据和碳同位素数据,重建H6事件期间中国西南地区季风气候环境的演化过程。结果显示:石笋JF2017的δ13C值在61811±204 a B.P.~59716±159 a B.P.时段显著偏重,持续大约2095 a,暗示该时段季风减弱和生态植被退化,对应北大西洋H6事件。H6事件期间,石笋JF2017的δ13C记录在61811~60848 a B.P.期间开始先逐渐偏重至最大值,随后发生短时间尺度的波动变化;最后在60848~59716 a B.P.期间缓慢偏轻至H6事件结束,整体呈现先逐渐偏重后又缓慢偏轻的趋势,内部存在百年际尺度的气候震荡,表明H6事件期间当地气候不稳定。石笋JF2017记录的百年际尺度的季风气候变化可能与热带辐合带和北大西洋经向翻转环流密切相关。展开更多
基金supported by the Natural Science Foundation of China(Nos.41572002,41830320,41272044,41472087,4183000426,41802016)
文摘Deep-water facies sections have advantages of recording complete information across the Permian-Triassic boundary(PTB). Here we present a detailed study on the conodont biostratigraphy and carbon isotope profile ranges from the Wuchiapingian-Changhsingian boundary(WCB) to the PTB of two deep-water facies sections at Zhuqiao and Shiligou in the Middle Yangtze region, western Hubei, South China. Fifteen species and three genera are identified. Eight conodont zones are recognized which in ascending order are the Clarkina orientalis, C. wangi, C. subcarinata, C. changxingensis, C. yini, C. meishanensis, Hindeodus parvus and Isarcicella isarcica zones. The onset of deposition of the deep-water siliceous strata of Dalong Formation in western Hubei began in the Late Wuchiapingian and persisted to the Late Changhsingian. Carbon isotope negative excursions occur near both the WCB and PTB in both sections. The WCB δ13 Ccarb negative excursion is in the C. orientalis and C. wangi zones. The PTB δ13 Ccarb negative excursion began in the C. yini Zone and extended to the I. isarcica Zone. The absence of several Changhsingian zones may indicate the difficulty of extracting conodonts from siliceous strata or the presence of an intra-Changhsingian hiatus.
文摘在末次冰期发生的6次海因里希事件(Heinrich事件,简称H事件)中,H6事件发生年代最早,对其研究较少,利用高分辨率石笋记录研究H6事件期间的气候环境变化,有助于理解高低纬度气候变化对H事件的响应过程。本文基于重庆市金佛洞石笋JF2017铀系测年数据和碳同位素数据,重建H6事件期间中国西南地区季风气候环境的演化过程。结果显示:石笋JF2017的δ13C值在61811±204 a B.P.~59716±159 a B.P.时段显著偏重,持续大约2095 a,暗示该时段季风减弱和生态植被退化,对应北大西洋H6事件。H6事件期间,石笋JF2017的δ13C记录在61811~60848 a B.P.期间开始先逐渐偏重至最大值,随后发生短时间尺度的波动变化;最后在60848~59716 a B.P.期间缓慢偏轻至H6事件结束,整体呈现先逐渐偏重后又缓慢偏轻的趋势,内部存在百年际尺度的气候震荡,表明H6事件期间当地气候不稳定。石笋JF2017记录的百年际尺度的季风气候变化可能与热带辐合带和北大西洋经向翻转环流密切相关。
