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遗迹化石组合的复杂性。遗迹化石的研究被称为“遗迹学”。选定用于研究的三角洲段要么显示河流和波浪影响的混合，要么显示保存在岩石结构中的河流和潮汐影响的混合。据推测，这些中间三角洲类型(与河流、波浪或潮汐主导的表现相反)具有独特的遗迹化石特征。这些特征包括遗迹化石多样性、挖掘强度、解释的动物行为类型、洞穴分布的一致性以及生物成因结构的大小范围。为该项目选择的案例研究将与先前评估的反映最终成员国的序列进行比较。物理沉积特征与观察到的遗迹化石特征的整合将增强我们识别其他地方类似沉积的能力，并将提供连续的三角洲类型，以帮助开发更广泛适用的沉积模型。更多的案例研究将探索三角洲不对称的概念；混合河浪影响三角洲的情况可能以三角洲扇下漂侧的优先河流沉积为特征。不对称三角洲产生独特的层序，从历史上看，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，以增强我们识别这些复杂层序的能力。

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.