Collaborative Research: Filling the Triassic geochronologic gap: A continuous cored record of continental environmental change in western North America

合作研究：填补三叠纪地质年代学空白：对北美西部大陆环境变化的连续核心记录。Paul Olsen，Lamont-Dougherty，EAR-0958976 George Gehrels，亚利桑那大学，EAR-0959107兰德尔·伊尔米斯，犹他大学，EAR-0958915丹尼斯·肯特，罗格斯大学，EAR-0958859罗兰·蒙迪尔，伯克利地质年代学实验室，EAR-0958723ABRACT三叠纪时期被有史以来最大的两次大灭绝打断，见证了现代生物群中大多数元素的进化，以及恐龙时代的到来。科罗拉多高原是这一时期陆地上生物和环境变化最丰富的档案之一，尽管经过了100多年的研究，但它在时间上仍然没有得到很好的校准，与全球其他记录的登记也很差。为了满足这一需求，我们将在美国亚利桑那州石化森林国家公园(PFNP)的几乎整个三叠纪时代段(Chinle组和Moenkopi组)钻取一个连续的a~500m岩心，这是地球上最著名和研究最深入的陆相三叠纪地层之一。需要一个连续的采样(核心)，才能将这一壮观的记录放在一个可靠的定量和可输出的时间尺度上，这在露头已被证明是不切实际的。石化森林岩芯将提供一个定量合理的参考剖面，其中磁性地层、地质年代学、环境和古生物数据被记录到一个明确叠加的共同厚度标尺上，并将提供原始的未风化样品。有了这样一个参考节，来自PFNP和周围区域的大量露头数据的整个集合就可以纳入全球框架。该孔将与垂直方向偏离30°，为方位导向器提供岩心-地层定向交叉点；此外，将使用全岩心扫描和指南针定向的声光电视图像和倾角测量仪将岩心的定向记录到孔壁上。岩心定向将有助于恢复高分辨率磁极地层学，以便与化石丰富的露头剖面进行对比。极性序列将由一系列从核心离散水平获得的高精度U-Pb锆石测年进行校准，并将提供关键数据，以填补晚三叠世全球陆地和海洋时间尺度的地质年代学空白。经年代校准的PFNP岩芯年代地层学将用于解决早中生代生物和环境变化的主要问题。这些问题包括：晚三叠世的海洋生物和大陆生物周转事件是否耦合；晚三叠世陆地上最大规模的动物群周转事件是否与巨大的马尼库阿根撞击同步；美国国家科学基金会资助的纽瓦克盆地天文校准的时间尺度是否与钦勒地层的高精度U-Pb锆石年龄数据一致；以及纽瓦克盆地湖泊记录中记录的周期性气候变化是否与米兰科维奇气候变化同步？除了核心产生的科学及其融入当地和全球环境和生物框架之外，该项目还将有一个重要的教育和宣传部分。石化森林国家公园是一个主要的旅游目的地，平均每年接待游客60万人次。我们计划利用这一巨大的资源，为公园开发一个关于取心项目及其重要科学成果的永久展览。在实际的取心活动中，我们将包括许多学生团体，包括新墨西哥大学/盖洛普大学的美洲原住民地球科学集中者和来自整个盖洛普地区的K-12学生。此外，我们亦会在公园举办多个工作坊，并邀请市民参与。该项目涉及来自不同机构的六个共同指标，将持续24个月，旨在提供基本地层学、测井、磁极和地质年代学数据的初步概要，供国际科学界用于进一步研究和与其他研究相结合，以及一个主要的外联平台，以更好地了解现代世界是如何形成的。

Collaborative Research: Filling the Triassic Geochronologic Gap: A Continuous Cored Record of Continental Environmental Change in Western North America.Paul Olsen, Lamont-Dougherty, EAR-0958976George Gehrels, University of Arizona, EAR-0959107Randall Irmis, University of Utah, Ear-0958915Dennis Kent, Rutgers University, EAR-0958859Roland Mundil, Berkeley Geochronology Laboratory, EAR-0958723ABSTRACTThe Triassic Period was punctuated by two of the largest mass-extinctions of all time and witnessed the evolution of most elements of the modern biota, as well as the advent of the age of the dinosaurs. One of the richest archives of the biotic and environmental changes on land for this period is on the Colorado Plateau, which despite over 100 years of study still remains poorly calibrated in time and poorly registered to the rest of the global record. To provide this desiderata, we will drill a continuous a ~500 m core through nearly the entire Triassic age section (Chinle and Moenkopi formations) at Petrified Forest National Park (PFNP), Arizona, USA, one of the most famous and best studied successions of the continental Triassic on Earth. A continuous sampling (core) is needed to place this spectacular record in a reliable quantitative and exportable time scale, which has proved impractical in outcrop. The Petrified Forest core will provide a quantitatively sound reference section in which magnetostratigraphic, geochronologic, environmental, and paleontologic data are registered to a common thickness scale with unambiguous superposition and will provide pristine unweathered samples. With such a reference section in hand the entire voluminous assemblage of outcrop data from the PFNP and the surrounding region can be integrated into the global framework. The hole will be deviated 30° from vertical to provide core-bedding orientation intersections for an azimuthal guide; additionally, the orientation of the core will be registered to the hole wall using whole-core-scans and compass-oriented acoustic and optical televiewer images and dipmeter surveys. Core orientation will facilitate the recovery of a high-resolution magnetic polarity stratigraphy for correlation to the fossil-rich outcrop sections. The polarity sequence will be calibrated by a series of high-precision U-Pb zircon dates obtained from discrete levels in the core, and will provide critical data to fill the geochronologic gap in global terrestrial and marine time scales for the Late Triassic. The age-calibrated chronostratigraphy of the PFNP core will be used to address major issues of early Mesozoic biotic and environmental change. These include whether marine and continental biotic turnover events in the Late Triassic were coupled; was the largest magnitude faunal turnover event on land during the Late Triassic synchronous with the giant Manicouagan impact; Is the NSF-funded Newark basin astronomically-calibrated time scale consistent with high precision U-Pb zircon age data from the Chinle Formation; and was the cyclical climate change recorded in the Newark basin lacustrine record paced by Milankovitch climate change? In addition to the science generated by the core and its integration into the local and global environmental and biotic framework, the project will have a major education and outreach component. The Petrified Forest National Park is a major tourist destination, averaging 600,000 visitors a year. We plan to leverage this huge resource by developing a permanent exhibit on the coring project and its important scientific results for the park. We will involve numerous student groups during the actual coring activities, including Native American geoscience concentrators at The University of New Mexico/Gallup and K-12 students from throughout the Gallup area. In addition, we will sponsor several workshops at the Park and will reach out to the general public for their participation. The project involves six co-PIs from different institutions and will last 24 months and is intended to provide an initial synopsis of basic stratigraphic, logging, magnetic polarity, and geochronologic data for utilization by the international scientific community for further research and integration with other studies, as well as a major platform for outreach, and a better understanding of how the modern world came to be.