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Updated: Jun 3, 2025

$Synchrotron X-ray Microdiffraction and Fluorescence Imaging of Mineral and Rock Samples$

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在波斯末期灭绝的后果中,可能存在的glendonite矿物伪形体

Musaab Al-Sarmi¹, Rachel Wood²

¹Grant Institute, School of Geosciences, University of Edinburgh, James Hutton Road, Edinburgh, EH9 3FE, UK. M.S.A.Al-Sarmi@sms.ed.ac.uk.

Scientific reports

|January 6, 2025

概括

可能的格伦多尼特,在冷水中形成的矿物质伪形体,在阿曼的三叠纪早期碳酸盐中被发现. 它们独特的碳同位素特征表明,在波斯纪末期的大规模灭绝之后,它们是在高度性海洋中形成的.

科学领域:

地质化学地质化学
古气候学古气候学
沉积物学的沉积物学

背景情况:

格伦多尼特是矿物质伪形体,通过硫酸盐还原在寒冷的海洋沉积物 (27°C) 中由ikaite (CaCO3·6H2O) 形成.
它们通常在冷水环境中发现,并作为过去海洋条件的指标.

研究的目的:

报告在亚热带海洋碳酸盐中首次可能出现的格伦多尼特.
为了研究这些结构在最早的三叠纪 (大约. 252 Ma) 后的末珀米纪大规模灭绝.

主要方法:

从阿拉伯高原进行地质现场观测和样本采集,阿曼.
使用扫描电子显微镜 (SEM) 和阴极发光成像进行微结构分析.
碳酸盐晶体和周围微观基质的稳定同位素分析 (δ13C).

主要成果:

类似于格伦多尼特的奥特基因碳酸盐晶体在三叠纪早期的石石中被发现.
SEM和阴极光发光揭示了三种矿物阶段:低Mg酸盐 (类型1和2) 和二氧化.
伪形体的 δ13C 值 (平均值 -0.43 ‰) 比矩阵 (平均值 -1.64 ‰) 更为正,表明海洋溶解的无机碳是碳来源.

结论:

观察到的结构是潜在的格伦多尼特,由于它们的亚热带发生和碳同位素特征,与典型的格伦多尼特不同.
据推断,它们的形成与波斯末期灭绝后海洋异常高的性和pH值 (>9) 有关,可能与冷,无氧水的上游有关.
这些发现提供了有关在波斯纪末期恢复期中中断的碳循环动态和海洋条件的见解.

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