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

摘要本项目侧重于在区域到大陆范围内重建生态系统的次要物种灭绝，通常是相对生态稳定的间隔期。这些地质上频繁发生的灭绝事件对生物圈的累积影响可能超过了更知名、相对罕见的全球大灭绝的影响。这样的小规模灭绝也令人感兴趣，因为它们可能在规模上更接近威胁现代生物群的许多人为栖息地改变过程。PIS将研究北美东部晚奥陶世三叶虫动物群中的两幕生物更替，这两幕生物更替是对与塔科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反应。他们将使用比较的方法来发现这两个事件的共同特征。较年轻的事件发生在Edenian-Maysvillian晚期，以三叶虫生物相侵入为特征，该生物相以奥列尼奥德和Triartrus为主，可能是与构造相关的盆地构造和/或海平面变化有关的区域古海洋变化的生物标志。其他环境变化在较老的事件(都灵-查特菲尔德边界区间)表现为在浅水环境中出现隐石型三叶虫，这类生物通常出现在较深的环境中。进入前陆盆地的两个断面，肯塔基州、田纳西州、弗吉尼亚州和纽约中部、安大略省南部，将被包括在研究中。俄克拉荷马州中南部，阿巴拉契亚前陆盆地之外的一个地区，将被用作控制？以帮助分离盆地独有的动物群模式。通过结合沉积岩序列和碳同位素曲线的数据，将重建环境。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进行全面的处理。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与研究。PIS还将通过开发一个虚拟展览，将灭绝研究的更广泛影响带给公众。和其他基于网络的教育资源，与俄克拉何马州自然历史博物馆的教育部合作。他们将不仅考虑“深度灭绝”，而且还考虑最近的过去(第四纪灭绝)和目前生物圈面临的挑战(如全球气候变化、海洋酸化和栖息地破坏等问题)。

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).