RUI: Integrated Stratigraphic and Sedimentological Analysis of the Cambro-Ordovican Inner Shelf, Colorado

[9419141] Myrow动物更替（包括大灭绝）的间隔与可能最终支配这些事件的各种沉积和构造过程之间的关系，对于全面理解地层记录至关重要。综合所有地区的沉积学、古生物学和地层学数据，在岸上-近海剖面中进行系统动力学的完整分析是必要的。寒武纪-奥陶纪界线段记录了包括Cordylodus provis牙形石带底部一次大灭绝在内的几次动物更替事件，但由于生物地层分辨率较差，在北美的内碎屑带沉积中通常未被识别或未被保存。沉积学和生物地层学数据来自有充分记录的寒武纪-奥陶纪台地和大盆地的近海地区以及其他地方，这些数据被用来提出动物灭绝的过程-响应模型，在许多情况下，这些模型包括被证实的令人兴奋的“事件”。不幸的是，从同时期的近地层沉积物中，很少或根本没有关于动物更替间隔与沉积和构造事件之间关系的信息，这些信息可以用来检验灭绝的原因或提出的狂喜事件的全球相关性。美国科罗拉多州中部和西部的寒武-奥陶系硅质碎屑和碳酸盐肉质岩石暴露良好，厚度较厚，为评估古北美寒武-奥陶系这一生物地层学不受约束的古地理区域在动物更替事件期间和之间的沉积体系时空变化提供了极好的机会。提出了一个为期两年的沉积学和地层学研究项目，其中使用牙形石生物地层学和沉积学标准识别不整合体将首次为科罗拉多州寒武纪-奥陶纪建立详细的层序地层格架。将这些沉积物的系统动力学与有充分记录的外部演替进行比较，将有助于更全面地了解动物群落的演化与沉积系统之间的相互作用。

9419141 Myrow The relationship between intervals of faunal turnover, including major extinctions, and various depositional and tectonic processes which may ultimately govern these events, is critical to the holistic understanding of the stratigraphic record. Integration of sedimentological, paleontological, and stratigraphic data from all regions in an onshore-offshore profile are required for a complete analysis of system dynamics. The Cambro-Ordovician boundary interval, which records several faunal turnover events including a major extinction at the base of the Cordylodus proavis conodont zone, is generally unrecognized or not preserved in inner detrital belt deposits in North America because of poor biostratigraphic resolution. Sedimentological and biostratigraphic data from well-documented Cambro-Ordovician platform and offshore areas of the Great Basin and elsewhere have been used to propose processes-response models for faunal extinctions, which in many cases include puported ecstatic "events". Unfortunately, little or no information exists from coeval proximal carnal deposits concerning the relationship of intervals of faunal turnover with depositional and tectonic events, which can be used as a test of the cause of extinctions or the global correlation of proposed ecstatic events. Well-exposed and thick Cambro-Ordovician siliciclastic and carbonate carnal rocks in central and western Colorado provide an excellent opportunity to assess spatial and temporal changes in depositional systems during and between faunal turnover events for this poorly understood and biostratigraphically unconstrained paleogeographic region in the Cambro-Ordovician of ancient North America. A two-year project is proposed for a sedimentological and stratigraphic study in which the recognition of unconformitites using conodont biostratigraphy and sedimentological criteria will for the first time enable construction of a detailed sequence-stratigraphic framework for the Cambro-Ordovician of Colorado. Co mparison of systems dynamics for these deposits with well-documented outboard successions will contribute to a more complete understanding of the interplay between the evolution of faunal communities and depositional systems.