Collaborative Research: Integrating Radioisotopic and Astronomical Time Scales for the Cretaceous

合作研究：整合白垩纪的放射性同位素和天文时间尺度

• 批准号: 0959108
• 负责人: Bradley Singer
• 金额: $ 40.64万
• 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: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2015-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0959108&HistoricalAwards=false
• 关键词: Collaborative; Research; Integrating; Radioisotopic; Astronomical

Collaborative Research: Integrating Radioisotopic and Astronomical Time Scales for the CretaceousPIs: Brad Singer, Steve Meyers, Brad SagemanThe Cretaceous period, between about 146 and 66 million years ago, was a time of sustained global warming during which atmospheric CO2 levels likely surpassed 800 part per million, similar to the amount predicted for 2100 by ?business-as-usual? emission scenarios. Cretaceous strata record evidence of high sea level, remarkably cyclic sedimentation thought to reflect orbitally-forced climate oscillation, high biological productivity, large scale igneous activity, and major perturbations of the carbon cycle during ocean anoxic events (OAEs). Understanding these phenomena, and their influence on fluxes into and out of the marine carbon reservoir, can provide deep-time analogues and a rich context for possible greenhouse scenarios of the future. However, a major limitation on our understanding of these deep-time analogues is the lack of accurate chronologies for assessing timing and rates of climatic and oceanic change. This project comprises a complete re-calibration of the Cretaceous time scale via new radioisotopic dating of volcanic ash beds integrated with chemical profiling and time-series analysis of sediment sequences aimed at detecting the influence of earth?s orbit and solar energy budget on sediment deposited in a shallow ocean setting. This will provide a solid foundation for the Cretaceous in the next iteration of the geologic time scale and should help resolve a number of outstanding problems. Moreover, the intercalibration of the 40Ar/39Ar and U-Pb radioisotopic chronometers - based on a common set of sanidine and zircon-bearing volcanic ash samples - will provide geologic tests of these decay systems, thereby addressing a primary goal of the NSF-sponsored EARTHTIME initiative and the entire geochronology community. This project will support two graduate student theses at UW-Madison and forge collaborations with active research groups in Europe, Canada and the US. Because Cretaceous strata also supply most of the global petroleum and natural gas reserves, our efforts to improve the 4-D understanding of Cretaceous rocks has high societal relevance with respect to these energy resources. To raise public awareness we have developed an outreach plan with staff of Lake Pueblo State Park, CO, which had 1.8 million visitors in 2008 and is home to one of the world's most classic exposures of Cretaceous strata, including the Cenomanian-Turonian Global Boundary Stratotype Section and Point (GSSP). Working in collaboration with the Park and Pueblo County school kids, as well as scientists at the USGS in Denver, we will design and install signs that highlight the science of geologic age determination and significance of the GSSP.

协作研究：将放射性病和天文时间尺度整合到of cretaceoustpis：Brad Singer，Steve Meyers，Brad Sagemanthe Ceraceous of Cretaceous of Cretaceous of Cretaceous of 146至6600万年前，是一个持续的全球变暖时期，在哪个大气中，大气CO2水平超过800份，可能超过800份，相似于2100乘以2100的企业？排放方案。 白垩纪地层记录了高海平面的证据，人们认为循环沉积物被认为反映了荒谬的气候振荡，高生物学生产力，大规模的火成活性以及海洋缺氧事件期间碳循环的主要扰动（OAES）。了解这些现象及其对海洋碳储层中磁通量的影响，可以为未来的可能的温室场景提供深层的类似物和丰富的背景。 但是，我们对这些深度类似物的理解的主要局限性是缺乏评估气候和海洋变化率的准确时间。 该项目包括对白垩纪时间尺度的完整重新校准，这是通过与化学分析和时间序列分析集成的新的放射性分析性，这些灰烬床对沉积物序列进行了集成，旨在检测地球轨道和太阳能预算对沉积物沉积在浅海环境中沉积的影响。 这将为白垩纪的下一个地质时间尺度迭代提供坚实的基础，并应有助于解决许多未来的问题。 此外，基于一组常见的sanidine和含氧火山灰样品的40AR/39AR和U-PB放射性化天文组织的构图将提供这些衰减系统的地质测试，从而解决NSF启发的Earthtime Enter Intiative Initiative otiative和整个地球机制社区的主要目标。 该项目将支持UW-Madison的两个研究生论文，并与欧洲，加拿大和美国的活跃研究小组进行锻造合作。 由于白垩纪地层还提供了大部分全球石油和天然气储量，因此我们提高对白垩纪岩石的4D理解的努力在这些能源方面具有很高的社会相关性。 为了提高公众意识，我们与科罗拉多州普韦布洛湖州立公园的工作人员制定了推广计划，该计划在2008年有180万游客，并且是世界上最经典的白垩纪地层暴露之一的所在地，包括Cenomanian-Turonian-Turonian全球边界型分层型和Point（GSSP）。 与公园和普韦布洛县学校的孩子以及丹佛USGS的科学家合作，我们将设计和安装标志，以强调GSSP的地质年龄确定和意义的科学。