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空白：北美西部大陆环境变化的连续岩芯记录

• 批准号: 0958915
• 负责人: Randall Irmis
• 金额: $ 8.06万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-15 至 2018-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0958915&HistoricalAwards=false
• 关键词: Collaborative; Research; Filling; Triassic; geochronologic

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.

合作研究：填补三叠纪地质年代学空白：北美西部大陆环境变化的连续岩心记录。Paul Olsen，Lamont-Doughnut，E-0958976乔治·格瑞尔斯，亚利桑那大学，E-0959107兰德尔·伊尔米斯，犹他州大学，E-0958915丹尼斯·肯特，罗格斯大学，E-0958859罗兰·蒙迪尔，伯克利地质年代学实验室，三叠纪时期被有史以来最大的两次大规模灭绝所打断，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。这一时期陆地上生物和环境变化的最丰富档案之一是在科罗拉多高原，尽管有100多年的研究，但仍然没有及时校准，也没有很好地记录到全球其他记录。为了满足这一要求，我们将在美国亚利桑那州石化森林国家公园（PFNP）的几乎整个三叠纪地层（Chinle和Moenkopi地层）钻取一个连续的~500 m岩心，该公园是地球上大陆三叠纪最著名和研究最好的继承地之一。 需要连续取样（岩心），以将这一壮观的记录置于可靠的定量和可输出的时间尺度中，这在露头中已被证明是不切实际的。石化森林岩心将提供一个定量的可靠参考剖面，其中磁性地层学、地质年代学、环境和古生物学数据将以明确的叠加方式记录到一个共同的厚度尺度上，并将提供原始的未风化样品。有了这样一个参考剖面，PFNP和周围地区的大量露头数据就可以纳入全球框架。钻孔将与垂直方向偏离30°，以便为方位角导向提供岩心-层理方向交叉点;此外，将使用全岩心扫描和罗盘导向的声学和光学电视图像以及地层倾角仪勘测将岩心方向与孔壁配准。岩心定向将有助于恢复高分辨率的磁极性地层，以便与富含化石的露头剖面进行对比。极性序列将通过一系列从岩芯离散水平获得的高精度U-Pb锆石年龄进行校准，并将为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提供关键数据。PFNP岩心的年龄校准年代地层学将用于解决中生代早期生物和环境变化的主要问题。这些问题包括：晚三叠世的海陆生物更替事件是否耦合;晚三叠世最大规模的陆地动物群更替事件是否与Manicouagan撞击事件同步; NSF资助的纽瓦克盆地天文学校准的时间尺度是否与Chinle组的高精度锆石U-Pb年龄数据一致;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地方和全球环境和生物框架外，该项目还将有一个重要的教育和外联部分。 石化森林国家公园是一个主要的旅游目的地，平均每年有60万游客。我们计划利用这一巨大的资源，为公园开发一个关于取芯项目及其重要科学成果的永久展览。 在实际的取芯活动中，我们将涉及许多学生团体，包括新墨西哥州/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，并会主动邀请市民参与。该项目涉及来自不同机构的六名共同研究员，将持续24个月，旨在提供基本地层、测井、磁极性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，并提供一个重要的外联平台，更好地了解现代世界是如何形成的。