1. Instituto Oceanográfico da Universidade de São Paulo, Fisica, Geoquimica e Geologia, Praça do Oceanográfico 191, São Paulo, São Paulo 05508-120, Brazil
2. John Hopkins University, Earth and Planetary Sciences, 3400 N. Charles Street, Baltimore, Maryland 21218, USA
3. Department of Geology, Western Washington University, 516 High St., Bellingham, Washington 98225, USA
4. University of Hawaii at Manoa, Hawaii Institute of Geophysics and Planetology, Honolulu, Hawaii 96822, USA