The Upper Devonian orbital cyclostratigraphy and numerical dating conodont zones from Guangxi,South China

作     者：GONG Yiming, XU Ran, TANG Zhongdao & LI Baohua Faculty of Earth Science, China University of Geosciences, Wuhan 430074, China Laboratory of Marine Geology, Tongji University, Shanghai 200092, China 

作者机构：Faculty of Earth Science China University of Geosciences Wuhan China Laboratory of Marine Geology Tongji University Shanghai China 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2005年第48卷第1期

页      面：32-41页

核心收录：

学科分类：070902[理学-地球化学] 070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 07[理学] 

基　　金：This work was jointly supported by the National Natural Science Foundation of China(Grant Nos.40072041 and 40472020) the Chinese Commission on Stratigrapby and the Climbing Project of Ministry of Science and Technology of China(SSER) 

主　　题：orbital cyclostratigraphy, conodont zone, numerical dating, mass extinction, Devonian, Guangxi, South China. 

摘      要：The hierarchically organized laminae, bundles, bundlesets and superbundlesets which correspond to a sub-Milankovitch, obliquity or precession, eccentricity and long eccentricity cyclothems, respectively, have been distinguished from the Upper Devonian Fras-nian-Famennian (F-F) transitional carbonate successions deposited in the carbonate-basin and slope facies of Guangxi, South China. The durations of cyclothems are 8000-10000a, 16667a or 33333a, 100000a and 400000a, respectively. The ratio of eccentricity to precession, eccentricity to obliquity, and long eccentricity to eccentricity is 1 : 6, 1 : 3 and 1 : 4 in the Devonian, respectively. Orbital cyclostratigraphical studies show that the durations of the conodont falsio-valis Zone, transitans Zone, punctate Zone, Lower hassi Zone, Upper hassi Zone, jamieae Zone, Lower rhenana Zone, Upper rhenana Zone, linguiformis Zone, Lower triangularis Zone, Middle triangularis Zone and Upper triangularis Zone are 0.4, 0.4, 0.4, 0.3, 0.4, 0.2, 0.8, 0.6, 0.8, 0.3, 0.3 and 0.3 Ma from bottom to top, respectively, and the duration of the Frasnian is 4.3 Ma. The conodont is the normal marine organism of the latest mass extinction (the latest linguiformis Zone) and the first recovery (including the whole Lower triangularis and Middle triangularis Zone) in the F-F transition. The conodont mass extinction and recovery lasted 200000-100000a and 0.6 Ma, respectively. We consider that average durations of the fossil zones calculated by reported numerical ages divided by fossil zone numbers within a stage or series or system cannot discovery complications and non-uniformity of evolutionary organisms and environments.