1. Lamont-Doherty Earth Observatory, Columbia University, Route 9W, Palisades, NY 10964, USA
2. Lamont-Doherty Earth Observatory and Queens College, City University of New York, Flushing, NY 11367, USA
3. Lamont-Doherty Earth Observatory and Barnard College, Columbia University, 3009 Broadway New York, NY 10027, USA
4. Department of Geology, University of Dhaka, Dhaka 1000, Bangladesh