Collaborative Research: Post-Impact Studies of the Chesapeake Bay Impact Structure: Quantifying Continental Margin Evolution

0606705Kominz该项目将扩展由CD资助的早期工作，涉及美国中大西洋边缘的地层分析。 PI参与了一个长期项目的取芯，测井和地震剖面的被动边缘，以提取全球海平面变化的地层记录和评估的作用，euclide，构造沉降和沉积物输入被动大陆边缘沉积。 这一努力最终导致了对过去1亿年海平面变化的估计，这一估计主要来自对新泽西陆上钻孔的回剥研究。切萨皮克湾撞击构造（CBIS）最近由美国地质勘探局钻探（在撞击坑内钻了5个岩心孔）。 PI（在CD资助下）参与了钻孔记录，并可以访问岩心进行分析。 初步研究报告将评估对地壳沉降的巨大影响的地球动力学效应，以及全球海平面和区域构造变化对塑造边缘地层记录的相对作用。 比较回剥（占沉积物负荷，压实，古水深度和盆地沉降的影响）的结果，从5个岩芯孔在火山口与以前分析的岩芯孔外的火山口将使他们能够量化的影响构造和全球海平面。 这些比较将提供一个自然的实验，量化影响产生的住宿与“正常”的热挠曲沉降，海平面和沉积物供应的被动大陆边的演变的相对影响。 该项目特别关注影响的短期和长期构造后果，东海岸新生代地层的细化，以及后始新世时期区域和全球海平面曲线的改进。 该项目还将检查撞击后立即沉积的沉积物的氧和碳同位素组成，以寻找与撞击造成的气候影响有关的同位素偏移。

0606705KominzThis project will extend earlier work funded by CD involving the analysis of stratigraphy on the US Mid-Atlantic Margin. The PIs have been involved in a long term project of coring, logging, and seismic profiling of this passive margin in order to extract global sea-level change from the stratigraphic record and evaluate the role of eustasy, tectonic subsidence, and sediment input on passive continental margin sedimentation. This effort has culminated in the development of a eustatic estimate for the past 100 million years derived largely from backstripping studies of New Jersey onshore boreholes. The Chesapeake Bay Impact Structure (CBIS) has recently been drilled by the USGS (5 coreholes drilled within the crater). The PIs were involved (with CD funding) in logging the holes and have access to the cores for analysis. The PIs will evaluate the geodynamic effects of a large impact on crustal subsidence and the relative roles of global sea-level and regional tectonic changes on molding the stratigraphic record of the margin. Comparison of backstripping (accounting for the effects of sediment loading, compaction, paleowater depth, and basin subsidence) results from the 5 coreholes in the crater with previously analyzed coreholes outside the crater will allow them to quantify the effects of tectonics and global sea level. These comparisons will provide a natural experiment quantifying the relative effects of impact-generated accommodation versus "normal" thermo-flexural subsidence, sea-level, and sediment supply on the evolution of a passive continental margin. The project specifically focuses on short and long term tectonic consequences of impact, refinement of Cenozoic stratigraphy for the east coast, and improvement of the regional and global sea level curve for post-Eocene time. The project will also examine the oxygen and carbon isotopic composition of sediments deposited immediately after the impact in order to look for isotopic excursions associated with climatic effects caused by the impact.