Integrated ichnological-sedimentological facies models: mixed-influence delta deposits

这个为期5年的项目探索了保存在三角洲古代沉积物中的痕迹化石组合的复杂性。 遗迹化石的研究被称为“遗迹学”。研究所选的三角洲间隔显示出在岩石结构中保存的河流和波浪影响的混合物，或河流和潮汐影响的混合物。据推测，这些中间三角洲类型（而不是河流，波浪或潮汐为主的表达）具有独特的痕迹化石特征。这些特征包括微量化石的多样性，穴居强度，解释动物行为的类型，洞穴分布的均匀性，以及生源结构的大小范围。 将物理沉积特征与观察到的痕迹化石特征相结合，将提高我们在其他地方识别类似沉积物的能力，并将提供一个三角洲类型的连续体，以帮助开发更广泛适用的沉积模型。额外的案例研究将探讨三角洲不对称的概念，混合河流波浪影响三角洲的情况下，其特点可能是在三角洲瓣的下游侧的优先河流沉积。不对称三角洲产生独特的继承，历史上，很难在岩石记录中识别。 本项目中评估的案例研究将试图建立标准，以提高我们识别这些复杂继承的能力。

This 5-year project explores the complexities of  trace fossil assemblages that are preserved in ancient deposits of deltas.  The study of trace fossils is referred to as "Ichnology".The deltaic intervals selected for study show either a mixture of river and wave influences, or a mixture of river and tide influences preserved in the structures of the rocks. It is hypothesized that these intermediate delta types (as opposed to river-, wave-, or tide-dominated expressions) possess unique trace fossil characteristics. Such characteristics include trace fossil diversity, burrowing intensity, types of interpreted animal behaviours, uniformity of burrow distribution, and size ranges of the biogenic structures.The case studies chosen for this project will be compared to previously assessed successions that reflect end-member states.  The integration of the physical sedimentary features with the observed trace fossil characteristics will enhance our ability to identify similar deposits elsewhere, and will provide a continuum of delta types to assist in the development of more broadly applicable depositional models. Additional case studies will explore the concept of delta asymmetry; a situation where mixed river-wave influenced deltas may be characterized by preferential river deposition on the downdrift side of the delta lobe. Asymmetric deltas yield unique successions and have, historically, been difficult to identify in the rock record.  The case studies evaluated in this project will attempt to erect criteria to enhance our ability to recognize these complex successions.