The Frasnian-Famennian mass extinction: insights from high-resolution sequence stratigraphy and cyclostratigraphy in South China

doi:10.1016/S0031-0182(02)00716-2

	The Frasnian-Famennian mass extinction: insights from high-resolution sequence stratigraphy and cyclostratigraphy in South China
	Chen, DZ ; Tucker, ME
刊名	PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
	2003-04-01
卷号	193 期号:1 页码:87-111
关键词	Frasnian-Famennian event mass extinction sequence stratigraphy cyclostratigraphy orbital forcing eustasy and eutrophication Late Devonian South China
ISSN号	0031-0182
DOI	10.1016/S0031-0182(02)00716-2
文献子类	Article
英文摘要	Two sequences (SFr, SFa), each 1-1.2 Myr in duration, are recognised in the strata across the Frasnian-Famennian (F-F) transition both in carbonate platform and interplatform basinal successions in South China. The sequence boundary between the two sequences is placed a little below the top of the Frasnian. The sequences are basically composed of coarsening-upward/bed-thickness increasing-upward cycles and shallowing-upward cycles (parasequences) in basinal and platform deposits respectively, which stack into cycle-sets (typically six to eight cycles). 10 and 12 cycle-sets are identified in sequences SFr and SFa respectively. These cycle-sets can be further grouped into larger-scale composite cycle-sets (herein termed mesocycle- and megacycle-sets with two and four cycle-sets respectively). This vertical cycle-stacking pattern and the hierarchy of cyclicity suggest a Milankovitch style of forcing such that the cycles and cycle-sets were formed in response to the orbital perturbations of precession (16-18 kyr) and eccentricity (similar to 100 kyr in duration), respectively. In the basinal cycles, smaller-scale rhythmic stratification beds (typically six to eight beds in a cycle) are extensive, and were likely caused by millennial-scale climatic forcing. In the lower sequence, SFr, the latest highstand deposits consist of calciturbidites and debrites in deep-water strata and fenestral limestones in shallow-water strata, representing a major (third-order) sea-level fall. Within these deposits, four cycle-sets are further identified in both coeval deep-water and platform successions. Succeeding deeper-water organic-rich facies, within which three cycles occur, are the transgressive deposits of the overlying Famennian sequence (SFa). These cycles represent three higher-frequency (16-18 kyr) sea-level fluctuations and accompanying anoxia, superimposed on a major third-order sea-level rise. The F-F boundary is placed at the top of the first cycle, based on conodont data. Thus, a major sea-level fall and then a rise occurred in the F-F transitional period. Faunal and sedimentological data reveal a massive biotic decline in concert with the major sea-level fall, and a further biotic demise coinciding with the major sea-level rise and its three superimposed higher-frequency sea-level fluctuations and accompanying anoxia. The F-F biotic crisis was therefore characterised by two episodes of step-down extinction. On the basis of Milankovitch orbital rhythms, the first major biotic extinction took place over -similar to 400 kyr, and the subsequent event was similar to 50 kyr in duration, i.e. similar to 450 kyr for the entire event. At the same time as the massive decline of normal-marine fossils during the latest Frasnian sea-level fall, there was widespread cyanobacterial growth and a thriving of planktonic calcispheres, suggesting eutrophic conditions. This situation could have caused a severe biotic loss, as a result of the deterioration of surface water clarity and formation of anoxic bottom waters due to overconsumption of oxygen through respiratory demands and decomposition by the cyanobacteria and phytoplankton. The subsequent rapid sea-level rise with superimposed higher-frequency sea-level fluctuations and accompanying anoxia could have caused rapid elevation of anoxic bottom waters and expansion of eutrophic surface waters over shallow-water platforms due to enhanced upwelling ocean currents and improved ocean circulation. This situation would have exerted further stresses upon the already-weakened biota, leading to a further biotic demise.
WOS关键词	ORGANIC-CARBON BURIAL ; SEA-LEVEL CHANGE ; GEOLOGICAL RECORD ; PLATFORM MARGIN ; ANOXIC EVENTS ; RUGOSE CORALS ; BOUNDARY ; CYCLES ; MIDDLE ; CRISIS
WOS研究方向	Physical Geography ; Geology ; Paleontology
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000181829100005
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/78881]
专题	中国科学院地质与地球物理研究所
通讯作者	Chen, DZ
作者单位	1.Univ Durham, Dept Geol Sci, Durham DH1 3LE, England 2.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Chen, DZ,Tucker, ME. The Frasnian-Famennian mass extinction: insights from high-resolution sequence stratigraphy and cyclostratigraphy in South China[J]. PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,2003,193(1):87-111.
APA	Chen, DZ,&Tucker, ME.(2003).The Frasnian-Famennian mass extinction: insights from high-resolution sequence stratigraphy and cyclostratigraphy in South China.PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,193(1),87-111.
MLA	Chen, DZ,et al."The Frasnian-Famennian mass extinction: insights from high-resolution sequence stratigraphy and cyclostratigraphy in South China".PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY 193.1(2003):87-111.