COLLABORATIVE RESEARCH: Towards a Milankovitch-Scale Stable Isotope Stratigraphy For the Late Oligocene to Early Miocene

合作研究：渐新世晚期到中新世早期的米兰科维奇规模稳定同位素地层学

• 批准号: 9725311
• 负责人: Benjamin Flower
• 金额: $ 9.14万
• 依托单位: University of South Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-01-01 至 2000-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9725311&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Towards; Milankovitch; Scale

9725311 Flower We propose to develop the first astronomically tuned stable isotope time series for the late Oligocene to early Miocene (21-27.5 Ma) with cores collected during Ocean Drilling Program (ODP) Leg 154 to Ceara Rise, western Equatorial Atlantic. This time series will be a composite record, constructed with the carbon and oxygen isotope records of benthic foraminifers from three Holes on Ceara Rise (Sites 926, 928, and 929). Through splicing, the composite will be stratigraphically continuous over a 6.5 m.y long interval. As such, it will be one of the single longest high-resolution isotope time series ever assembled. Preliminary work has demonstrated the feasibility of the proposed approach. In fact, efforts are now underway to tune the magnetic susceptibility and existing stable isotope records to orbital spectra for this interval (in collaboration with N.J. Shackleton). With the astronomically tuned isotope record we will be able to (1) estimate the relative ages of the Oligocene/Miocene boundary, (18O maxima Oi2a, Mi1, Mi1a (as well as all minor events), and (2) characterize in unprecedented detail the evolution of late Oligocene/early Miocene climate variability (ice-volume/temperature). Several important benefits will be derived from the results of this investigation. For one, the proposed astronomically tuned isotope time series will serve as a global standard reference section by which all other late Oligocene-early Miocene marine sequences are compared. It will be possible, using stable isotope stratigraphies, to correlate and calibrate either long or short segments of sedimentary sections to this record, thereby significantly improving the accuracy of age models. More importantly, by providing the framework for reconstructing changes in climate, deep ocean circulation and chemistry, the tuned Ceara Rise isotope records should greatly enhance paleoceanographic and paleoclimatic research on this interval. In sum, the proposed Milankovitch-scale records will rep resent a significant advance in Cenozoic stratigraphy and Earth history.

9725311 Flower 我们建议开发第一个天文学调整的渐新世晚期到中新世早期（21-27.5 Ma）的稳定同位素时间序列，其岩心是在海洋钻探计划（ODP）154段至赤道大西洋西部塞阿拉海隆期间收集的。 该时间序列将是一个复合记录，由塞阿拉隆起三个洞（926、928 和 929 号地点）的底栖有孔虫的碳和氧同位素记录构建。 通过拼接，复合材料将在 6.5 m.y 长的间隔内保持地层连续性。 因此，它将成为有史以来最长的高分辨率同位素时间序列之一。 初步工作证明了所提出方法的可行性。 事实上，目前正在努力将磁化率和现有的稳定同位素记录调整到该区间的轨道光谱（与 N.J. Shackleton 合作）。 通过天文调谐同位素记录，我们将能够（1）估计渐新世/中新世边界的相对年龄（18O最大值Oi2a、Mi1、Mi1a（以及所有次要事件），以及（2）以前所未有的细节描述渐新世晚期/中新世早期气候变化（冰量/温度）的演变。 这项调查的结果。 首先，拟议的天文调谐同位素时间序列将作为全球标准参考部分，用于比较所有其他晚渐新世 - 早中新世海洋序列。 使用稳定同位素地层学，可以将沉积剖面的长段或短段与该记录进行关联和校准，从而显着提高年龄模型的准确性。 更重要的是，通过提供框架 为了重建气候、深海环流和化学的变化，调整后的塞阿拉海隆同位素记录将大大加强这一区间的古海洋学和古气候研究。 总之，拟议的米兰科维奇尺度记录将代表新生代地层学和地球历史的重大进步。