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DOI	10.1016/j.jseaes.2024.106033
	Orbital cycles recorded in Early Cambrian shales with implications for organic matter accumulation
	Jin, Siding; Liu, Yan; Ma, Chao; Zhang, Quanlin; Chen, Anqing
发表日期	2024
ISSN	1367-9120
EISSN	1878-5786
起始页码	263
卷号	263
英文摘要	The Qiongzhusi Formation, dating back to the Early Cambrian period and located in the Yangtze Block of the South China Craton, is distinguished by its organic -rich shales. These shales, which developed during the pivotal Second Cambrian Explosion have increasingly become a focal point of scholarly research. Previous studies have identified a stratigraphic transition in Qiongzhusi Formation, signaling a major shift in the Early Cambrian ocean -climate system. While existing geochemical analyses have shed light on primary productivity and redox conditions, the impact of orbital -forcing on organic matter accumulation remains poorly understood. This study reports on the results of iron to aluminum ratio (Fe/Al) and total organic carbon (TOC) assessments conducted on Early Cambrian shale samples from drill hole JS103 in the Sichuan Basin. The analysis spans approximately 10.8 million years, covering Stages 2-3 (from -526 Ma to -515 Ma), and is based on data derived from astronomical tuning. Our findings reveal hierarchal periodicities corresponding to 405, -100 and -36-kyr cycles. Notably, the observed phase shifts in the 405-kyr filtered Fe/Al and TOC data series around -521 Ma indicate potential orbitally driven variations in carbon cycling, possibly influencing monsoon dynamics. Higher Fe/Al ratios indicate enhanced preservation under anoxia environmental conditions, while low ratios alongside high TOC suggest increased productivity due to nutrient influx. The phase shifts observed in the coupled series on a 405-kyr cycle scale imply a significant transformation of the ocean -climate system, driven by strong eccentricity pacing during the second Cambrian explosion. This suggests that Cambrian biotic radiation could have been influenced by astronomical forcing and variations in oceanic oxygen levels.
英文关键词	Orbital timescale; Eccentricity pacing; Shales; Astronomical calculations; Bio-evolution
语种	英语
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:001176465800001
来源期刊	JOURNAL OF ASIAN EARTH SCIENCES
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/299125
作者单位	Chengdu University of Technology; Chengdu University of Technology; Chengdu University of Technology; Sinopec
推荐引用方式 GB/T 7714	Jin, Siding,Liu, Yan,Ma, Chao,et al. Orbital cycles recorded in Early Cambrian shales with implications for organic matter accumulation[J],2024,263.
APA	Jin, Siding,Liu, Yan,Ma, Chao,Zhang, Quanlin,&Chen, Anqing.(2024).Orbital cycles recorded in Early Cambrian shales with implications for organic matter accumulation.JOURNAL OF ASIAN EARTH SCIENCES,263.
MLA	Jin, Siding,et al."Orbital cycles recorded in Early Cambrian shales with implications for organic matter accumulation".JOURNAL OF ASIAN EARTH SCIENCES 263(2024).