GRANMUD: Granulometric and geochemical contrast comparison of carbonate mud lithified under natural and laborytory conditions

碳酸盐软泥，或泥晶，其岩化的对应物，形成了整个地球历史上石灰石的主要成分。泥晶数据通常代表沉积环境的地球化学平均值，但它们的起源（台地、斜坡、水柱、自生）和矿物学（文石、（Mg-）方解石）往往缺乏约束，胶结过程中形成的碳酸盐沉淀的地球化学和体积意义也是如此。这就是所谓的泥晶问题。大块基质泥晶构成了许多处理过去碳循环或化学地层学的地球化学研究的（知之甚少的）支柱。在这里，我建议研究沉积物柱中不同程度自然岩化的海相碳酸盐岩软泥，并将这些泥晶的粒度数据与在受控实验室条件下岩化的碳酸盐岩软泥的粒度数据进行比较。重点是文石泥（海相）和方解石泥（湖相）。在实验室中，碳酸盐泥浆使用示踪元素进行岩化，以便清楚地分离沉淀（水泥）和碎屑（泥浆）成分。目标是物理分离泥晶的特定成分，并研究它们的起源、矿物学、颗粒形态和地球化学。建议采用已建立的Paris方法，并对新的Kiel （SPLITT）方法进行测试。虽然这两种方法都不能弥补文石或高镁钙质软泥的沉积后成岩蚀变，但认为该研究是朝着正确方向迈出的重要一步。

Carbonate ooze, or micrite, its lithified counterpart, forms a main constituent of limestones throughout Earth History. Micrite data commonly represent a geochemical average of the depositional environmeht, but their origin (platform, slope, water column, authigenic) and mineralogy (aragonite, (Mg-)calcite) is often poorly constrained as is the geochemical and Volumetrie significance of carbonate precipitates formed during cementation. This is referred as the micrite problem . Bulk-matrix micrites form the (poorly understood) backbone of many geochemical studies dealing with past carbon cycle or chemostratigraphy. Here l propose to investigate marine carbonate oozes naturally lithified within the sediment column to variable degrees and to compare granulometric data from such micrites with such from carbonate oozes lithified under controlled laboratory conditions. The focus is both on aragonite mud (marine) as well as calcite mud (lacustrine). In the laboratory, carbonate muds are lithified using a tracer element in order to clearly separate precipitated (cement) and detrital (mud) components. The goal is to physically separate specific components of micrite and to investigate their origin, mineralogy, grain morphology and geochemistry. It is proposed to use the well established Paris method and to test the new Kiel (SPLITT) method. It is acknowledged that neither method can compensate for any post-depositional diagenetic alteration of aragonitic or high-Mg calcitic oozes but it is believed that this research is an important step in the right direction.