干旱区生态环境知识资源中心(Arid): Improved constraints on open-system processes in fossil reef corals by combined Th/U, Pa/U and Ra/Th dating: A case study from Aqaba, Jordan

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DOI	10.1016/j.gca.2018.11.024
	Improved constraints on open-system processes in fossil reef corals by combined Th/U, Pa/U and Ra/Th dating: A case study from Aqaba, Jordan
	Obert, J. Christina 1,2; Scholz, D.1; Felis, T.3; Lippold, J.4; Jochum, Klaus P.2; Andreae, Meinrat O.5,6
通讯作者	Obert, J. Christina
来源期刊	GEOCHIMICA ET COSMOCHIMICA ACTA
ISSN	0016-7037
EISSN	1872-9533
出版年	2019
卷号	245 页码:459-478
英文摘要	Here we present Th-230/U, Pa-231/U as well as( 226)Ra/ Th-230 isotope ratios from five fossil reef corals of Last Interglacial origin from the Gulf of Aqaba, Northern Red Sea. The results show clear evidence for open-system behaviour with strongly elevated delta U-234 values and U concentrations indicating post-depositional U addition. The combined application of all isotope systems enables us to better constrain the nature and timing of the open-system processes than only based on the Th-230/U data. Quantitative modelling of the diagenetic processes allowed us to reproduce the trends in the isotope ratios. Two of the five corals were probably affected by two separate phases of U addition with different delta U-234 values. The trends observed for two other corals can be explained by U addition followed by U loss. The fifth coral shows signs of both U gain and loss at the same time in the more recent past. The timing of the diagenetic processes is remarkably similar for the five corals and can be constrained to approx. 1 and 6 thousand years (ka) and 100 and 102 ka after coral growth, respectively. Based on the modelling results, we suggest that conventional Pa-231/Th-230 ages provide the best estimate for the true age of four of the five corals, which range from 109.1 to 114.1 ka. This implies a late Last Interglacial time of deposition. For the fifth coral, the most reliable age estimate is the conventional( 230)Th/U age of one of the subsamples (117.3 ka), based on a concordia diagram for all subsamples. The timing of the modelled open-system processes suggests that the early event of U addition was associated with interaction of the corals with U-234-enriched seawater or saline groundwater. The later open-system event can be described as U redistribution within the coral reef, since some corals apparently lost U while others gained U. The timing of the second event is broadly consistent with the Bolling-Allerod interstadial, which was probably characterised by enhanced wetness in this typically hyper-arid region. (C) 2018 Elsevier Ltd. All rights reserved.
英文关键词	U-series dating Coral open-system behaviour Last Interglacial Concordia diagram
类型	Article
语种	英语
国家	Germany ; Saudi Arabia
收录类别	SCI-E
WOS记录号	WOS:000453771600027
WOS关键词	MELTWATER PULSE 1B ; SEA-LEVEL ; U-TH ; MASS-SPECTROMETRY ; URANIUM ; DIAGENESIS ; AGES ; ACCURATE ; PRECISE ; ISOTOPE
WOS类目	Geochemistry & Geophysics
WOS研究方向	Geochemistry & Geophysics
来源机构	King Saud University
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/215904
作者单位	1.Johannes Gutenberg Univ Mainz, Inst Geosci, Mainz, Germany; 2.Max Planck Inst Chem, Climate Geochem Dept, Mainz, Germany; 3.Univ Bremen, MARUM Ctr Marine Environm Sci, Bremen, Germany; 4.Heidelberg Univ, Inst Earth Sci, Heidelberg, Germany; 5.Max Planck Inst Chem, Mainz, Germany; 6.King Saud Univ, Dept Geol & Geophys, Riyadh, Saudi Arabia
推荐引用方式 GB/T 7714	Obert, J. Christina,Scholz, D.,Felis, T.,et al. Improved constraints on open-system processes in fossil reef corals by combined Th/U, Pa/U and Ra/Th dating: A case study from Aqaba, Jordan[J]. King Saud University,2019,245:459-478.
APA	Obert, J. Christina,Scholz, D.,Felis, T.,Lippold, J.,Jochum, Klaus P.,&Andreae, Meinrat O..(2019).Improved constraints on open-system processes in fossil reef corals by combined Th/U, Pa/U and Ra/Th dating: A case study from Aqaba, Jordan.GEOCHIMICA ET COSMOCHIMICA ACTA,245,459-478.
MLA	Obert, J. Christina,et al."Improved constraints on open-system processes in fossil reef corals by combined Th/U, Pa/U and Ra/Th dating: A case study from Aqaba, Jordan".GEOCHIMICA ET COSMOCHIMICA ACTA 245(2019):459-478.