Experimental Mudstone Sedimentology: Evolving Methodology, Measuring Thresholds and Rates, Investigating Processes

实验泥岩沉积学：演化的方法论，测量阈值和速率，研究过程。泥岩是最丰富的，但却最不为人所知的沉积岩类型。纵观地球历史，这些细粒沉积物保存了古代地表条件和气候的记录，以及生物标志物和化石形式的有机活动。然而，尽管它们具有重要意义，我们对泥岩沉积过程的认识仍然是初级的。在一个新建的水槽中，PI进行了一系列初步实验，并证明，与传统观点相反，快速水流（10-30厘米/秒）造成的泥浆沉积在广泛的沉积环境中应该是一种普遍现象。粘土的絮凝作用导致粘土絮凝体的顺质运移，形成低起伏的迁移波纹，形成泥层。古泥岩的排列磁性结构表明，这一过程在岩石记录中的许多泥岩中也很活跃。对现有水槽设施的拟议修改将使PI能够更有效地测量控制泥浆沉积的物理参数，并记录由不同参数组合（例如盐度、粘土类型、流速）产生的小尺度沉积特征。这些数据将为了解泥浆沉积的物理条件提供基础，并将是整合泥浆沉积的物理、化学和生物参数的第一步。

Experimental Mudstone Sedimentology: Evolving Methodology, Measuring Thresholds and Rates, Investigating ProcessesJuergen Schieber and John SouthardIndiana University and MITEAR-0617128ABSTRACTMudstones are the most abundant, yet least understood sedimentary rock type. Throughout Earth history, these fine-grained sediments have preserved a record of ancient surface conditions and climates, as well as of organic activity in the form of biomarkers and fossils. In spite of their significance, however, our understanding of the depositional processes of mudstones is still rudimentary. In a newly built flume the PI's have conducted a series of initial experiments and can demonstrate that, contrary to conventional wisdom, mud deposition from swift currents (10-30 cm/sec) should be a common phenomenon in a wide range of sedimentary environments. Flocculation of clays leads to bedload transport of clay floccules, formation of low relief migrating ripples, and to buildup of mud layers. The aligned magnetic fabrics of ancient mudstones suggest that this process was active for many mudstones in the rock record as well. Proposed modifications to the existing flume facility will allow the PI's to more efficiently pursue the measurement of physical parameters that control mud deposition, and record the small scale sedimentary features that result from different combinations of parameters (e.g. salinity, clay type, flow velocity). These data will provide the baseline for understanding the physical conditions of mud deposition, and will be the first step in an effort to integrate physical, chemical, and biological parameters of mud deposition.