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.

地层学和古生物学中正在进行的地理信息学倡议的最终产品将是在线电子地层记录。它面临着三个挑战：收集足够的数据，整合多个数据库，以及维护能够将所有本地数据记录汇编成地质时间轴的工具。第三个挑战是对化石记录进行排序，我们建议解决它面临的三个障碍：(1)相同年龄的化石生物群可能由于栖息地和保存的影响而不同；(2)必须对非常大的数据集进行小块测序，并将结果无缝地拼接在一起；(3)越来越多的过时的和有指纹的灰层需要更有效地利用。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，提出了同样的问题。奥陶纪和志留纪跨越了近1亿年的早期古生代，传统上被笔石和牙形刺细分，这两个化石分支具有不同的生态和保存特征，这限制了它们在很大程度上相互排斥的领域的使用。北美东部的莫霍基（晚奥陶世）恰恰呈现出一种具有挑战性的地质环境，在这种环境中，我们可以建立和测试时间序列和缝合方法。莫霍克地层在该地区广泛暴露，并产生了丰富的化石记录，其中包括各种各样的，但有些地方特有的牙形石动物群。Taconic前陆盆地的深水沉积物围绕着阿巴拉契亚边缘的顺地壳演替。这些地层包含一套洲际分布的笔石动物群，但很少有描述的牙形刺组合。大量蚀变火山灰沉积（k -膨润土）通过一套沿盆地内部边缘的过渡相将这些相连接起来。尽管有这些优点，但由于短剖面的普遍存在、构造的复杂性和动物群相的局限性，妨碍了克拉通和盆地演替之间精确可靠的对比，从而限制了我们比较它们不同动物群和构造历史的能力。学术价值：我们建议结合(1)莫霍克纪和早期辛辛那提期k -斑长岩的地球化学指纹（泥质年代学）和u - pb年代学；(2)北美东部11个地区的莫霍克纪牙形石和笔石的重新研究；(3)全球奥陶系牙形石和笔石化石记录的计算机辅助测序。这项工作将提供一个详细的时间和古生态框架，在此框架内，通过严格的定量技术，将生物相信息应用于化石记录的时间排序。在第1步和第2步中，我们将特别关注含有kbentonite的牙形刺和笔石的序列，特别是牙形刺和笔石紧密结合的区域。尽管有广泛的时间地层学信息，但我们在一个时间间隔内的工作结果仍然令人烦恼，这将对当地和全球地层学的基本问题产生影响。在本研究过程中，我们将测试北美中部和东部中上奥陶统现有的交替对比模型。这些结果将为研究奥陶系和志留系的动物更替和多样性变化提供一个改进的、年龄校准的基础。最重要的是，这项工作将导致时间尺度构建和验证的改进技术的发展。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来排序事件。该项目符合EARTHTIME在制定高精度时间尺度方面交叉培训地层学家和地质年代学家的目标。培养博士生2人（少数），本科生3人。我们将整合四所院校的努力，其中两所是少数族裔院校（UCR和UALR），以一种新的合作方式，促进每所院校所有学生和pi之间的互动。本科生将作为现场和实验室助理参与pisa和研究生，并将作为高级研究项目分配项目的一部分。每位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，作为阿肯色州奋斗计划的一部分。教师将根据他们的经验开发课堂项目。因此，该项目通过提高中学教师的知识基础和科学课程来影响后代的学生。