气候变化领域集成服务门户(CCPortal): Improving the detection of shell alteration: Implications for sclerochronology

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DOI	10.1016/j.palaeo.2020.109968
	Improving the detection of shell alteration: Implications for sclerochronology
	Coimbra R.; Huck S.; de Winter N.J.; Heimhofer U.; Claeys P.
发表日期	2020
ISSN	0031-0182
卷号	559
英文摘要	Sclerochronology makes use of (fossil) shell-archives to establish records allowing for investigation of high-resolution environmental dynamics. Nevertheless, this potential can often not be fully exploited due to the interplay between paleoenvironmental variability, vital effects and the potential diagenetic modification of skeletal materials, which often results in highly complex records. A novel dynamic approach, aiming to separate pristine from altered shell material for paleoclimate and paleoenvironmental reconstructions is proposed. Seventeen fossil bivalve shells (requieniid rudists, pectinids and chondrodonts) from two neighbouring Lower Cretaceous (Albian) shallow-water sections (Lusitanian Basin, western Portugal) were analysed for their major and trace elemental compositions using high-resolution quantitative μXRF line scans. Their complex records were subject to a novel statistical analysis protocol, which tested mono- and multi-species datasets, as well as comparing shells from both locations. Characteristic elemental associations reveal the differential impact of early and late diagenetic alteration processes. The incorporation of elements associated with detrital contribution (Fe, Si, Al) is attributed to syn-depositional bioerosion (shell-boring). In clear contrast, shell-portions showing a strong correlation between Fe and Mn are indicative of later diagenetic alteration. The influence of each process is different at each site, revealing local differential alteration pathways. Mono-specific comparisons provides identical geochemical responses, suggesting that intra-specific differences do not control the observed elemental patterns. In contrast, inter-species tests rendered a clear separation in the way elements are incorporated in the shells of pectinids and requieniids (e.g., as evidenced by differences in Mg or Sr content). Such differences can be linked to differential biomineralization pathways, easily detected by the applied method. We present a new, dynamic method for distinguishing pristine from altered shell material, not relying on arbitrary diagenetic thresholds for trace element content. By clearly identifying shell-alteration pathways, syn- to post-depositional processes are recognized. A progressive cleaning of the elemental dataset allows paleoenvironmental studies to be based on the most pristine data, contributing to unravelling the complex interplay between climate, environmental dynamics and their impact on biomineralization processes and sclerochronological archives. © 2020 Elsevier B.V.
英文关键词	Diagenesis; Geochemistry; Paleoenvironment; Shells; Statistical analysis
语种	英语
scopus关键词	bioerosion; biomineralization; bivalve; Cretaceous; fossil record; intraspecific variation; paleoclimate; paleoenvironment; reconstruction; shallow water; shell; skeletal remains; trace element; Atlantic Ocean; Lisboa [Portugal]; Lusitanian Basin; Mono; Portugal; Portugal; Bivalvia; Pectinidae
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/150327
作者单位	GeoBioTec, Departamento de Geociências, Universidade de Aveiro, Portugal; Institut of Geology, Leibniz University Hannover, Germany; Analytical, Environmental and Geochemistry Department, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, 1050, Belgium; Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Netherlands
推荐引用方式 GB/T 7714	Coimbra R.,Huck S.,de Winter N.J.,et al. Improving the detection of shell alteration: Implications for sclerochronology[J],2020,559.
APA	Coimbra R.,Huck S.,de Winter N.J.,Heimhofer U.,&Claeys P..(2020).Improving the detection of shell alteration: Implications for sclerochronology.Palaeogeography, Palaeoclimatology, Palaeoecology,559.
MLA	Coimbra R.,et al."Improving the detection of shell alteration: Implications for sclerochronology".Palaeogeography, Palaeoclimatology, Palaeoecology 559(2020).