CRYSTALLOGRAPHY AND DIAGENESIS IN FOSSIL CRANIID BRACHIOPODS
CRYSTALLOGRAPHY AND DIAGENESIS IN FOSSIL CRANIID BRACHIOPODS
复制标题
颅骨腕足类化石的晶体学和成岩作用
DOI：
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发表时间：
2007
期刊：
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通讯作者：
Jennifer England
中科院分区：
文献类型：
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作者：
A. Pérez;M. Cusack;Jennifer England
摘要：生物矿化的基本问题之一是生物如何在生物矿化过程中控制晶体取向。了解成岩变化如何影响化石生物矿物结构中原始晶体模式的保存，为这种评估提供了先验的基础信息。利用电子背散射衍射（EBSD）技术，对晚奥陶世和晚白垩世的腕足类化石Petrocrania scabiosa和Crania craniolaris进行了高空间分辨率的晶体学分析。EBSD分析表明，P. scabiosa保留了大部分原始晶体学特征，包括来自单个方解石片和层的数据，而C. craniolaris仅保留了反映片在层间晶体学连续性的碎片性晶体学数据。数据表明，原始晶体特征的保存与壳层超微结构和地质年代无关。此外，这些结果使我们能够提出一系列由于成岩作用而导致的“晶体损失”演化的步骤。
Abstract: One of the fundamental questions in biomineralization is how organisms control crystallographic orientation during biomineral production. The understanding of how diagenetic changes influence the preservation of original crystallographic patterns in fossilized biomineral structures provides a priori fundamental information for such an assessment. Fossil craniid brachiopods Petrocrania scabiosa (Late Ordovician) and Crania craniolaris (Late Cretaceous) are analysed using electron backscattered diffraction (EBSD) to provide crystallographic data at high spatial resolution in the structural context. EBSD analyses show that P. scabiosa maintains most of the original crystallographic signature, including data from individual calcite tablets and laminae, while C. craniolaris only retains fragmentary crystallographic data reflecting the crystallographic continuity of tablets across laminae. Data show that the preservation of the original crystallographic signature is independent of that of shell ultrastructure and geological time. In addition, results allow us to propose a series of steps in the evolution of ‘crystallographic loss’ due to diagenesis.