This study successfully isolates a fraction of intra-crystalline proteins from shells of the marine gastropod Patella vulgata and assesses the suitability of these proteins for IcPD (Intra-crystalline Protein Diagenesis) geochronology. We discuss the mineralogical composition of this gastropod, investigated for the first time by X-ray diffraction mapping, and use the results to inform our sampling strategy. The potential of the calcitic rim and of a bulk sample (containing both apex and rim) of the shell to act as stable repositories for the intra-crystalline proteins during diagenesis is examined. The composition and the diagenetic behaviour of the intra-crystalline proteins isolated from different locations within the shell are compared, highlighting the necessity of targeting consistent sampling positions.

We induced artificial diagenesis of both intra-crystalline and whole-shell proteins by conducting high-temperature experiments in hydrous environment; this allowed us to quantify the loss of amino acids by leaching and therefore evaluate the open- or closed-system behaviour of the different fractions of proteins. The results obtained provide further confirmation that patterns of diagenesis vary according to the protein sequence, structure, and location within or outside the intra-crystalline fraction. As Patella is frequently found in the fossil record, both in archaeological and geological contexts, the application of IcPD geochronology to this biomineral opens up the possibility to obtain reliable age information from a range of sites in different areas of the world.

这项研究成功地从海洋腹足动物髌骨的壳中分离出一小部分结晶内蛋白质，并评估这些蛋白质对 IcPD（结晶内蛋白质成岩）地质年代学的适用性。我们讨论了这种腹足动物的矿物组成，这是第一次通过 X 射线衍射图进行研究，并使用结果来告知我们的采样策略。检查了方解石边缘和壳的大量样品（包含顶点和边缘）在成岩过程中作为晶体内蛋白质的稳定储存库的潜力。对从壳内不同位置分离的晶体内蛋白质的组成和成岩行为进行了比较，突出了针对一致采样位置的必要性。

我们通过在含水环境中进行高温实验，诱导了晶内和全壳蛋白的人工成岩作用；这使我们能够通过浸出来量化氨基酸的损失，从而评估不同蛋白质部分的开放或封闭系统行为。获得的结果进一步证实了成岩作用的模式根据蛋白质序列、结构和结晶内部分内外的位置而变化。由于在考古和地质背景下的化石记录中经常发现髌骨，因此将 IcPD 地质年代学应用于这种生物矿物开辟了从世界不同地区的一系列地点获得可靠年龄信息的可能性。