Liang Hu , Matthias Alberti , Ying Tian , Zheng Fang , Yanhong Pan
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引用次数: 0
Abstract
Biominerals in hard parts are widely used as paleoenvironmental archives, employing proxies such as elemental and isotopic composition, microstructure, and crystallography. However, the effective selection and application of these proxies in fossil materials depends on their preservational potential. Here we evaluated the preservational potential of these proxies through controlled experiments on bivalves, one of the commonly used fossils in paleoenvironmental reconstructions. We utilized cultured Mytilus galloprovincialis specimens at five controlled temperatures to investigate the impact of elevated temperatures on various proxies extracted from both aragonitic and calcitic components of the same shell, including isotopic composition, microstructure and crystallography. Elevated temperatures first induced changes in the oxygen isotope composition (in both aragonite and calcite), followed by modification in aragonitic parts, such as changes in the aragonite phase, textures, nacre microstructure, and grain size of aragonite crystals. Despite aragonite's susceptibility to temperature, the microstructure and texture of calcite remained largely unaltered, demonstrating significantly higher resilience. Our findings emphasize the preservational potential of different shell proxies under heat exposure, ranging from oxygen isotopes to microstructure and texture. A ranking of preservation potential provides a practical guide for selecting well-preserved specimens, as textures and microstructures are not always reliable indicators. In distinguishing aragonite from calcite in fossils, our study pioneers a new avenue by proposing the analysis of high-angle boundary (HAB) content, including twin boundaries, as a reference for altered aragonite.
期刊介绍:
Palaeogeography, Palaeoclimatology, Palaeoecology is an international medium for the publication of high quality and multidisciplinary, original studies and comprehensive reviews in the field of palaeo-environmental geology. The journal aims at bringing together data with global implications from research in the many different disciplines involved in palaeo-environmental investigations.
By cutting across the boundaries of established sciences, it provides an interdisciplinary forum where issues of general interest can be discussed.