Establishing the Magnesium Isotope Signature of Dolomites

镁是大陆地壳中含量第八丰富的元素，也是水文和生物系统以及世界海洋中的重要元素。镁是白云岩的关键元素，但关于准同生期和沉积后白云岩的镁同位素特征以及成岩作用对白云岩δ26Mg的影响的研究资料最多也就很少。这为使用波鸿沉积物和同位素地质系最先进的MC-ICP-MS设备对各种白云岩类型进行深入的镁同位素研究形成了强烈的动机。本研究计划的目的是：(1)验证特定白云岩类型以特定δ26Mg特征为特征的假设；(2)以阿尔卑斯地区上三叠统中白云岩（Dolomia Principale）为例，评估准同生白云岩δ26Mg增加成岩蚀变的影响。根据前两个目标的结果，考虑在项目第三年编制选定地层间隔的时间序列δ26Mg地层学。在这项研究的框架内，我们打算与来自几个机构的专家同事合作，以获得广泛选择的白云岩案例，包括前寒武纪和显生宙的材料。这项工作的结果对那些关注白云岩问题的人来说具有重要意义，并且有可能代表一种新的和独立的方法来研究白云岩形成和稳定过程中活跃的动力学过程。

Magnesium is the 8th most abundant element in the continental crust and an important element in the hydrological and biological system and in the world’s oceans. Magnesium is the key element of dolomite and yet, published data on the magnesium-isotope signature of pene-contemporaneous and post-depositional dolomites and the impact of diagenesis on dolomite δ26Mg are at best scarce. This forms a strong motivation for an in depth magnesium-isotope study of various dolomite types using the state-of-the-art MC-ICP-MS facilities at the department of Sediment- and Isotope Geology at Bochum. The aims of this research proposal are (1) to test the hypothesis that specific dolomite types are characterized by specific δ26Mg signatures and (2) to assess the effects of increasing diagenetic alteration of pene-contemporaneous dolomite δ26Mg using the example of the Upper Triassic Hauptdolomit (Dolomia Principale) in the Alps. Depending on the outcome of the first two objectives, the compilation of a time-series δ26Mg stratigraphy of selected stratigraphic intervals is considered for the third project year. In the framework of this research, we intend to collaborate with expert colleagues from several institutions in order to obtain a broad selection of well-studied dolomite case examples including Precambrian and Phanerozoic material. The outcome of this work is of significance for those concerned with the dolomite problem in general and has the potential to represent a novel and independent approach for kinetic processes active during dolomite formation and stabilization.