CAREER: Deciphering the Beat of a Timeless Rhythm- The Future of Astrochronology

职业：破译永恒节奏的节拍——占星年代学的未来

• 批准号: 1151438
• 负责人: Stephen Meyers
• 金额: $ 51.21万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1151438&HistoricalAwards=false
• 关键词: CAREER; Deciphering; Beat; Timeless; Rhythm

CAREER: Deciphering the Beat of a Timeless Rhythm - The Future of AstrochronologyStephen MeyersUniversity of WisconsinEAR-1151438The geologic record provides the only available documentation of long-term environmental change, but in order to accurately interpret this record and evaluate rates of change we require a means to tell time. The dating of sedimentary deposits via astrochronology has become one of the most important tools for construction of the state-of-the-art geologic time scale. This method utilizes the geologic record of climate oscillations - those ascribed to quasi-periodic changes in the Earth's orbit and rotation - to measure the passage of time directly from repetitive sedimentary layers. The impact of astrochronology on the quantification of 'deep-time' has been truly revolutionary, and the approach is now even employed to fine-tune (e.g., calibrate) radioisotopic data and to test their veracity. However, although the method has resulted in the development of extraordinary high-resolution time scales, the uncertainties in deep-time astrochronologies are almost uniformly poorly constrained. This CAREER project will address the three fundamental challenges to the field of deep-time astrochronology using a new computational approach, with the goal of enhancing the accuracy and precision of an astronomically tuned geologic time scale.The first of the challenges to deep-time astrochronology arises from the near ubiquitous lack of adequate independent time control (e.g., radioisotopic data with sufficiently small errors) to unambiguously calibrate observed spatial rhythms to temporal periods, which prohibits direct confirmation of the proposed astronomical tempo. This shortcoming has resulted in much confusion, including multiple incompatible interpretations for a given stratigraphic record, and has also roused suspicion about the veracity of astrochronology. The second major challenge is the corruption of the orbital insolation signal as it propagates through the climate system and into various depositional systems (including sedimentation rate changes and hiatus), which may ultimately render the preserved astronomical signature unidentifiable, or worse yet, result in erroneous inferences about the preserved tempo. The third major challenge to deep-time astrochronology is the lack of accurate orbital insolation solutions beyond ~50 Ma, which necessitates the distinction between 'floating' and 'anchored' astrochronologies. These three challenges will be addressed by uniting and building upon important scientific advances within the fields of Quaternary paleoclimate, cyclostratigraphy, geochronology and geophysics. The new computational approach will provide fundamental methodological advances towards the achievement of an astronomically tuned Phanerozoic time scale, and will yield a more complete understanding of how orbital insolation changes influenced the surficial Earth System during both icehouse and greenhouse intervals of Earth history. As a test case for the new methodology, this project will evaluate the Eocene Green River Formation, a stratigraphic unit of great historical significance to the field of cyclostratigraphy. A central feature of this CAREER project is the integration of research and education. Involvement in the UW-Madison PEOPLE program engages youth in scientific discovery, and increases underrepresented minority participation in Geoscience. Partnership with colleagues at the UW-Madison Geology Museum will culminate in the development of a new geologic time display that will be seen by ~45,000 visitors per year, and participation in their science outreach program will result in a new model railroad exhibit (the 'Deep-Time Express') to be deployed at large public events. Establishment of a national research hub for the intercalibration of astrochronologic and radioisotopic time scales will build community within the field of geochronology, and will facilitate the distribution of software and tutorials generated for the project. Finally, the development of courses in chronostratigraphy and cyclostratigraphy, coupled with student participation in research, will provide a unique interdisciplinary training for the integration of astrochronologic and radioisotopic time scales, thus cultivating future leaders in the field of geochronology.

职业：解密永恒节奏的节拍-天文年代学的未来斯蒂芬·迈耶威斯康星大学-1151438地质记录提供了唯一可用的长期环境变化的文件，但为了准确地解释这一记录和评估变化率，我们需要一种方法来告诉时间。通过天体年代学测定沉积物的年代已成为建立最先进的地质时标的最重要工具之一。这种方法利用气候振荡的地质记录--那些归因于地球轨道和自转的准周期性变化的气候振荡--直接从重复的沉积层测量时间的流逝。天体年代学对“深时”量化的影响是真正革命性的，这种方法现在甚至被用来微调（例如，校准）放射性同位素数据并检验其准确性。然而，虽然该方法已经导致了非常高分辨率的时间尺度的发展，在深时间天体年代学的不确定性几乎一致约束不足。这个CAREER项目将使用一种新的计算方法来解决深时天体年代学领域的三个基本挑战，目标是提高天文学调整的地质时标的准确性和精度。深时天体年代学的第一个挑战来自于几乎无处不在的缺乏足够的独立时间控制（例如，误差足够小的放射性同位素数据），以明确地将观测到的空间节奏校准到时间周期，这禁止直接确认所提出的天文克里思。这一缺陷导致了许多混乱，包括对一个给定的地层记录的多种不相容的解释，也引起了对天体年代学准确性的怀疑。第二个主要挑战是轨道日射信号在通过气候系统传播并进入各种沉积系统（包括沉积速率变化和间断）时的损坏，这可能最终使保存的天文特征无法识别，或者更糟的是，导致对保存的克里思的错误推断。深时天体年代学的第三个主要挑战是缺乏超过~50 Ma的精确轨道日射解，这就需要区分“浮动”和“锚定”天体年代学。这三个挑战将通过统一和建立在第四纪古气候，旋回地层学，地质年代学和地球物理学领域的重要科学进展来解决。新的计算方法将提供基本的方法学进展，实现天文学调整的中生代时间尺度，并将产生一个更完整的了解轨道日射变化如何影响地球表面系统在冰库和温室间隔的地球历史。作为新方法的测试案例，该项目将评估始新世绿色河组，这是一个对旋回地层学领域具有重大历史意义的地层单位。这个CAREER项目的一个中心特点是研究和教育的整合。参与澳门银河人计划从事青年科学发现，并增加在地球科学中代表性不足的少数民族参与。与同事们在澳门皇冠体育地质博物馆的伙伴关系将最终在一个新的地质时间显示，将由〜 45，000参观者每年看到的发展，并在他们的科学推广计划的参与将导致一个新的模型铁路展览（“深时间”）被部署在大型公共活动。建立一个天体年代学和放射性同位素时间尺度相互校准国家研究中心将在地质年代学领域内建立社区，并将促进为该项目制作的软件和教程的分发。最后，年代地层学和旋回地层学课程的发展，加上学生参与研究，将为天体年代学和放射性同位素时间尺度的整合提供独特的跨学科培训，从而培养地质年代学领域的未来领导者。