Collaborative Research: Foreland basin development and biotic change in Late Ordovician trilobite faunas of eastern North America

本项目的重点是在区域到大陆尺度上重建生态系统的小规模破坏，通常是相对生态稳定的间断性间隔。这些地质上频繁的灭绝事件对生物圈的累积影响可能超过了更知名的，相对罕见的全球大规模灭绝的影响。这种小规模的改变也是令人感兴趣的，因为它们可能在规模上更接近于威胁现代生物区系的许多人为生境改变过程。PI将研究北美东部晚奥陶世三叶虫动物群的生物周转的两个事件，这些事件是对塔康造山运动期间阿巴拉契亚前陆盆地发展相关的深刻环境变化的响应。他们将使用比较的方法来发现这两个事件的共同特征。年轻的事件，在后期的Edenian-Maysvillian的特点是由oleniodean，Triarthrus，可能是区域古海洋学的变化与构造相关的变化在盆地配置和/或euglyca的生物签名为主的三叶虫生物相的入侵。其他环境变化表现在较老的事件（都灵？Chatfieldian边界间隔）在浅水环境中出现的隐石三叶虫，一组通常出现在更深的环境。两条横断面进入前陆盆地，肯塔基州？田纳西？弗吉尼亚和纽约中部？安大略南部将被纳入研究。中南部俄克拉荷马州，阿巴拉契亚前陆盆地以外的地区，将被用作？控制？来帮助分离出这个盆地特有的动物群模式。将沉积岩序列数据与碳同位素曲线相结合，重建环境。该项目包括对三叶虫动物群的系统学、生物地层学和古生态学的全面研究。拟议活动的更广泛影响在于教育和培训;四名研究生和至少四名本科生将参加这项研究。PI也将带来更广泛的影响，研究的预防公众通过制定一个？虚拟展览？以及其他基于网络的教育资源，与俄克拉荷马州自然历史博物馆的教育部门合作。他们不仅会考虑在？深时间？，还有最近的过去（第四纪灭绝）和生物圈目前面临的挑战（如全球气候变化、海洋酸化和栖息地破坏）。

ABSTRACT This project focuses on the minor extinctions that restructure ecosystems on regional to continent-wide scales and commonly punctuate intervals of relative ecological stability. These geologically frequent extinction events may have a cumulative effect on the biosphere that exceeds the impact of the better-known, relatively rare global mass extinctions. Such minor extinctions are also of interest because they may be closer in scale to many of the processes of anthropogenic habitat alteration that threaten the modern biota. PIs will study two episodes of biotic turnover in the Late Ordovician trilobite faunas of eastern North America that are responses to profound environmental changes associated with the development of the Appalachian Foreland Basin during the Taconic Orogeny. They will use a comparative approach to discover features common to both events. The younger event, in the late Edenian-Maysvillian is characterized by incursions of trilobite biofacies dominated by the oleniodean, Triarthrus that may be the biotic signatures of regional paleoceanographic shifts associated with tectonically-related changes in basin configuration and/or eustasy. Other environmental changes are expressed at the older event (Turinian?Chatfieldian boundary interval) by the appearance in shallow water settings of cryptolithine trilobites, a group that typically occurs in deeper environments. Two transects into the foreland basin, Kentucky?Tennessee?Virginia and central New York?southern Ontario, will be included in the study. South-central Oklahoma, a region outside of the Appalachian foreland basin, will be used as a ?control? to help isolate faunal patterns that are unique to the basin. The environments will be reconstructed by combining data from the sedimentary rock succession with carbon isotope curves. The project includes a full treatment of the systematics, biostratigraphy and paleoecology of the trilobite faunas. The broader impact of the proposed activity lies in education and training; four graduate students and at least four undergraduates will participate in the study. PIs will also bring the broader implications of the study of extinctions to the public by developing a ?virtual exhibit? and other web-based educational resources in collaboration with the Education Department at the Oklahoma Museum of Natural History. They will consider not only extinctions in ?deep time?, but also the recent past (Quaternary extinctions) and the challenges currently facing the biosphere (such issues as global climate change, ocean acidification, and habitat destruction).