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Rapid quantification of calcite in north Atlantic sediments by DRIFTS and its climate significance — Example of drilling site U1308

GE Yun, LIU Lian-wen, JI Jun-feng, BALSAM William   

  1. 1. State Key Laboratory of Mineral Deposits Research, Institute of Surficial Geochemistry, Department of Earth Sciences, Nanjing University, Nanjing 210093, China; 2. Department of Earth and Environmental Sciences, University of Texas at Arlington, Arlington, Texas 76019, USA
  • Received:2009-06-20 Revised:2009-06-20 Online:2009-06-20 Published:2009-06-20

Abstract: A rapid and simple method based on diffuse reflectance coupled with lnfrared Fourier Transform Spectroscopy (DRIFTS)was developed for the quantification of calcite content in deep sea sediments. Taking the drilling site U1308 from North Atlantic as an example, the standard sediment sample was put on DRIFTS detection and the area ratio of calcite peak 713 cm-1 to quartz peak 800 cm-1 was set as independent variable. The calcite content was obtained by Vacuum-Gasometric technique, and the correlation between DRIFTS area ratio and calcite content was analysed and a regression equation was validated. The results show that the DRIFTS method can clearly quantify the calcite in sediments, which is especially sensitive for the low calcite content with good mesure precision and detection limit. In this way, we determined the calcite content for drilling site U1308 sediments of recent nearly 1 Ma, which displays typical Atlantic carbonate cycle. It reflects intensified changes in calcite preservation during mid-Brunhes event (MBE) and mid-Pleistocene evolution (MPE). In response to global climate change, it also reflects the driven force mechanism of global carbon reservoir changes in North hemisphere ice sheet expansion and influence of deep water circulation on calcium carbonate preservation.