Collaborative research: Automated sequencing of the fossil record: Improved Methods and insights from Mohawkian (Ordovician) geochronology, tephrochronology, and biostratigraphy

合作研究：化石记录的自动测序：莫霍克纪（奥陶纪）地质年代学、岩石年代学和生物地层学的改进方法和见解

• 批准号: 0519106
• 负责人: Scott Samson
• 金额: $ 17万
• 依托单位: Syracuse University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0519106&HistoricalAwards=false
• 关键词: Collaborative; research; Automated; sequencing; fossil

The end-product of ongoing geoinformatics initiatives in stratigraphy and paleontology will be an onlineelectronic stratigraphic record. It faces three challenges: to compile sufficient data, to integratemultiple databases, and to maintain tools that can assemble all the local data records into a geologic timeline. The third challenge amounts to sequencing the fossil record and we propose to address three of theobstacles it faces: (1) Fossil biotas of the same age may differ as a result of habitat and preservationeffects; (2) Very large data sets must be sequenced in smaller pieces and the results stitched seamlesslytogether; (3) Increasing numbers of dated and fingerprinted ash beds need to used more effectively. Wepropose a case study of manageable geographic and temporal extent that, nevertheless, raises these sameissues. The Ordovician and Silurian periods span almost 100 million years of early Paleozoic time and aretraditionally subdivided by graptolites and conodonts - two fossil clades with different ecological andpreservational traits that restrict their use to largely mutually exclusive domains.The Mohawkian (Late Ordovician) of eastern North America presents precisely the type ofchallenging geological environment in which to build and test the temporal sequencing and stitchingapproaches that we envision. Mohawkian strata are widely exposed in the region and yield a rich fossilrecord that includes diverse, but somewhat endemic, conodont faunas. The epicratonic succession isrimmed along the Appalachian margin by deeper water sediments of the Taconic foreland basin. Thesestrata contain a suite of inter-continentally distributed graptolite faunas, but few described conodontassemblages. Numerous altered volcanic ash deposits (K-bentonites) link these facies through a set oftransitional facies along the interior basin margin. Despite these advantages, the prevalence of shortsections, structural complexity, and facies limitation of the faunas impedes precise and reliable correlationbetween the cratonic and basinal successions, consequently limiting our ability to compare their disparatefaunas and tectonic histories.Intellectual Merit: We propose to combine (1) geochemical fingerprinting (tephrochronology) andU-Pb geochronology of K-bentonites from the Mohawkian and early Cincinnatian with (2) a restudy oflate Mohawkian conodonts and graptolites from eleven regions across eastern North America and (3)computer assisted sequencing of the global Ordovician conodont and graptolite fossil record. This workwill provide a detailed temporal and paleoecological framework within which to refine the application ofbiofacies information to the temporal sequencing of the fossil record via rigorous quantitative techniques.We will focus in steps 1 and 2 particularly on conodont and graptolite-bearing successions that contain Kbentonites,and especially on regions where conodonts and graptolites occur in close association.The results of our work in a time interval that remains troublesome in spite of a wide range of timestratigraphicinformation will bear upon fundamental questions in both local and global stratigraphy. Inthe course of this study we will test existing alternate correlation models for the mid Upper Ordovician ofcentral and eastern North America. The results will provide an improved, age-calibrated basis for studiesof faunal turnover and diversity change in the Ordovician and Silurian. Most importantly, the work willlead to the development of improved techniques for time scale construction and validation.Broader Impact: The data and tools we develop will be shared immediately through the CHRONOSproject and will investigate technological solutions that are not being addressed by CHRONOS tosequence events. The project meets the EARTHTIME goal of cross-training stratigraphers andgeochronologists in developing high precision time-scales. We will train two PhD students (one aminority), and three undergraduates. We will integrate the efforts of four institutions, two with largeminority enrolment (UCR, UALR), in a new collaboration that will facilitate the interaction of all thestudents and PIs at each institution. Undergraduates will participate as field and lab assistants for the PIsand for the graduate students, and will be given pieces of the project as senior research projects. Eachstudent will present aspects of the research at a professional meeting. The project will also include asecondary school teacher who will work alongside PI Leslie during the summer as part of the ArkansasSTRIVE program. The teacher will develop class projects based on their experiences. The project thusimpacts future generations of students by enhancing a secondary education teacher's knowledge base andscientific curriculum.

地层学和古生物学领域正在进行的地理信息学举措的最终产品将是在线电子地层记录。它面临三个挑战：编译足够的数据、集成多个数据库以及维护可以将所有本地数据记录组装成地质时间轴的工具。第三个挑战是对化石记录进行测序，我们建议解决它面临的三个障碍：（1）由于栖息地和保护效应，同一年龄的化石生物群可能有所不同； (2) 非常大的数据集必须分成更小的片段进行排序，并将结果无缝地拼接在一起； (3) 越来越多的有日期和指纹的灰床需要更有效地利用。我们提出了一个可管理的地理和时间范围的案例研究，然而，它提出了这些相同的问题。奥陶纪和志留纪跨越了早古生代的近一亿年，传统上按笔石和牙形石细分——这两个化石分支具有不同的生态和保存特征，限制了它们在很大程度上相互排斥的领域的使用。北美东部的莫霍克阶（晚奥陶纪）准确地呈现了具有挑战性的地质环境类型，在该环境中构建和测试我们所采用的时间排序和拼接方法设想。莫霍克阶地层在该地区广泛暴露，并产生丰富的化石记录，其中包括多种但有些特有的牙形刺动物群。外皮层序沿阿巴拉契亚边缘被塔科尼克前陆盆地更深的水沉积物包围。这些地层包含一套洲际分布的笔石动物群，但很少描述牙形刺组合。许多蚀变火山灰沉积物（钾膨润土）通过沿盆地内部边缘的一组过渡相将这些相连接起来。尽管有这些优点，但动物群的短断面、结构复杂性和相限制的普遍存在阻碍了克拉通和盆地序列之间精确可靠的关联，从而限制了我们比较不同动物群和构造历史的能力。智力优点：我们建议结合（1 ) 莫霍克阶和早期辛辛那阶钾膨润土的地球化学指纹图谱（年代学）和 U-Pb 地质年代学(2) 对北美东部 11 个地区的晚期莫霍克期牙形刺和笔石进行重新研究，以及 (3) 对全球奥陶纪牙形刺和笔石化石记录进行计算机辅助测序。这项工作将提供一个详细的时间和古生态框架，在该框架内通过严格的定量技术完善生物相信息在化石记录时间排序中的应用。我们将在步骤 1 和 2 中特别关注包含 Kbentonites 的牙形石和笔石序列，特别是在牙形石和笔石密切相关的地区。尽管地层信息的时间范围很广，但我们在一个时间间隔内的工作结果仍然很麻烦，这将涉及一些基本问题在局部和全球地层学中。在本研究过程中，我们将测试北美中部和东部中上奥陶统的现有替代相关模型。研究结果将为奥陶纪和志留纪动物群更替和多样性变化的研究提供改进的、年龄校准的基础。最重要的是，这项工作将促进时间尺度构建和验证改进技术的开发。更广泛的影响：我们开发的数据和工具将立即通过 CHRONOS 项目共享，并将研究 CHRONOS 未解决的技术解决方案以对事件进行排序。该项目满足了交叉培训地层学家和地质年代学家开发高精度时间尺度的地球时间目标。培养博士生2名（氨基1名），本科生3名。我们将整合四所机构的努力，其中两所拥有大量少数族裔学生（UCR、UALR），进行新的合作，以促进每个机构的所有学生和 PI 之间的互动。本科生将作为 PI 和研究生的现场和实验室助理参与其中，并将获得该项目的部分内容作为高级研究项目。每个学生将在专业会议上介绍研究的各个方面。该项目还将包括一名中学教师，他将在夏季与 PI Leslie 一起工作，作为 ArkansasSTRIVE 计划的一部分。老师将根据他们的经验开发课堂项目。因此，该项目通过增强中等教育教师的知识基础和科学课程来影响未来几代的学生。