A global survey of marine magnetic anomalies to constrain the Late Cretaceous-Eocene time scale

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Part 1The Late Cretaceous-Cenozoic geomagnetic polarity time scale based on the C-sequence magnetic anomalies created by seafloor spreading provides an independent measure that can guide magnetic polarity time scale in sediments and thus its importance to geochronology. Since the time scale based on magnetic anomalies was last attempted over 20 years ago the global data has grown considerably, and detailed finite plate rotations have been determined on several spreading centers. The PI plans to use these new results for time scale information to substantially update the time scale information provided by marine magnetic anomalies by extending the analysis originally done in the S Atlantic to several spreading centers. The results will impact all of geological disciplines that require accurate time scale for the Cretaceous through Tertiary interval. The educational components comprise undergraduate training, workshop for Earth2Class program for K-12 science teachers and outreach at Lamont Open House. Part 2The Late Cretaceous-Cenozoic geomagnetic polarity time scale based on the C-sequence magnetic anomalies created by seafloor spreading provides an independent measure that can guide magnetic polarity time scale in sediments and thus its importance to geochronology. The latest in-depth analysis of marine magnetic anomalies, mostly based on the South Atlantic patterns, was carried out more than twenty years ago. The global marine magnetic anomaly record has since grown considerably, and detailed finite plate rotations have been determined on several spreading centers (Central and SE Indian Ridge, Pacific-Antarctic Ridge, NE Pacific, Central N Atlantic). These new results have not been fully analyzed for time scale information, and magnetic anomalies are presently underutilized. The proposed project is to substantially update the time scale information provided by marine magnetic anomalies by extending the analysis originally done in the S Atlantic to several spreading centers. Advancing the state of the art in dating and correlating past events has significant implications in a wide range of geoscience disciplines. To enhance the broader understanding of the fundamental concepts behind the development of a quantitative geologic time scale and to promote scientific training, the project will support an undergraduate student during a 10-week summer internship at the Lamont-Doherty Earth Observatory. The PI will closely supervise the student in selecting suitable profiles, identifying magnetic anomalies, constructing reversal distance data sets, and preparing a presentation of the results. The PI will also run a workshop on the proposed project in the Earth2Class program, where K-12 science teachers are introduced to research by Lamont scientists. The quantification of deep time will be presented to the general public during the Lamont Open House, an annual outreach event that attracts thousands of visitors.