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Revisiting the Ceara Rise, equatorial Atlantic Ocean: isotope stratigraphy of ODP Leg 154

Roy Wilkens, Thomas Westerhold, Anna Joy Drury, Mitchell Lyle, Thomas Gorgas, Jun Tian
2017 Climate of the Past Discussions  
Isotope stratigraphy has become the method of choice for investigating both past ocean temperatures and global ice volume. Lisiecki and Raymo (2005) published a stacked record of 57 globally distributed benthic δ<sup>18</sup>O records versus age (LR04 stack). In this study LR04 is compared to high resolution records collected at all of the sites drilled during ODP Leg 154 on the Ceara Rise, in the western equatorial Atlantic Ocean. Newly developed software is used to check data splices of the
more » ... ta splices of the Ceara sites and better align out-of-splice data with in-splice data. Core images recovered from core table photos are depth and age scaled and greatly assist in the data analysis. The entire splices of ODP Sites 925, 926, 927, 928 and 929 were reviewed. Most changes were minor although several were large enough to affect age models based on orbital tuning. A Ceara Rise composite record of benthic δ<sup>18</sup>O is out of sync with LR04 between 1.80 and 1.90&amp;thinsp;Ma, where LR04 exhibits 2 maxima but where Ceara Rise contains only 1. The interval between 4.0 and 4.5&amp;thinsp;Ma in the Ceara Rise compilation is decidedly different from LR04, reflecting both the low amplitude of the signal over this interval and the limited amount of data available for the LR04 stack. A regional difference in benthic δ<sup>18</sup>O of 0.2&amp;thinsp;‰ relative to LR04 was found. Independent tuning of Site 926 images and physical property data to the Laskar et al. 2004 orbital solution and integration of available benthic stable isotope data from the Ceara Rise provides a new regional reference section for the equatorial Atlantic covering the last 5 million years
doi:10.5194/cp-2016-140 fatcat:l445h6m4e5fufb73b2bjvtifzq