Integrated Ichnological-Sedimentological Facies Models for Mixed-Influence Delta Deposits

混合影响三角洲沉积物的综合水相-沉积相模型

• 批准号: 184293-2012
• 负责人: MacEachern, James
• 金额: $ 1.97万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=569708
• 关键词: Integrated; Ichnological; Sedimentological; Facies; Models

The 5-year project explores the complexities of trace fossil suites that are preserved in the ancient deposits of deltas. The study of trace fossils is referred to as "Ichnology". The deltaic deposits selected for analysis range from outcrop to subsurface core datasets, and show either a mixture of river and wave influences, or a mixture of river and tide influences preserved in the structures of the sedimentary rocks. It is hypothesized that these intermediate delta types (as opposed to river-, wave-, or tide-dominated end member expressions) possess unique trace fossil characteristics. The study will focus on trace fossil diversity, burrowing intensity, interpreted animal behaviours (ethology), burrow distribution, and size ranges of the biogenic structures. These biogenic characteristics will be integrated with physical and chemical processes of sedimentation, as reflected in the sedimentary rocks. Genetic stratigraphic frameworks (e.g., sequence stratigraphy) will be developed for the successions in order to assess delta lobe architectures and differentiate delta lobe switching from changes imposed by relative sea level. The case studies chosen for this project will be compared to previously assessed successions that reflect end-member states as well as mixed influence conditions. The integration of physical sedimentary features with the trace fossil characteristics will enhance our ability to identify similar deposits elsewhere, and will provide a continuum of delta types to facilitate development of more broadly applicable depositional models. Case studies also will explore the concept of delta asymmetry, a situation common to mixed river-wave influenced deltas wherein preferential river discharge occurs on the downdrift side of the delta lobe. Asymmetric deltas yield unique, spatially discrete successions and have, historically, been difficult to identify in the rock record. Differentiation of such deltaic successions from persistently brackish-water (salinity stressed) settings is challenging. The case studies evaluated in this project will attempt to erect criteria that enhances our ability to recognize these complex asymmetric successions.

这个为期5年的项目探索了保存在古代沉积物中的痕迹化石套件的复杂性 三角洲。遗迹化石的研究被称为“遗迹学”。 选择用于分析的三角洲沉积物的范围从露头到地下岩心数据集，并且显示出河流和波浪影响的混合物，或者河流和潮汐影响的混合物保存在沉积岩的结构中。据推测，这些中间三角洲类型（相对于河流，波浪，或潮汐为主的端员表达）具有独特的痕迹化石特征。这项研究将侧重于微量化石的多样性，挖掘强度，解释动物行为（行为学），洞穴分布，和生物结构的大小范围。这些生物成因特征将与沉积的物理和化学过程相结合，反映在沉积岩中。成因地层框架（例如，层序地层学），以评估三角洲瓣结构，并区分三角洲瓣转换与相对海平面的变化。 为这个项目选择的案例研究将与以前评估的继承进行比较， 最终成员国以及混合影响条件。将物理沉积特征与遗迹化石特征相结合，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，以促进更广泛适用的沉积模型的开发。 案例研究还将探讨三角洲不对称的概念，一种常见的混合河流波浪影响的三角洲，其中优先河流流量发生在三角洲瓣的下漂侧的情况。不对称三角洲产生独特的，空间上离散的继承和历史上，很难识别的岩石记录。区分这种三角洲的继承持续咸水（盐度强调）设置是具有挑战性的。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的不对称继承的能力。