Pacific Seafloor

• Main Authors: West Indian, East Tethyan, J. J. Mahoney, R. Frei, M. L. G. Tejada, X. X. Mo, P. T. Leat, T. F. Nägler
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1997
• Subjects: Alexander Island; Indian; Pacific; Antarc*; Antarctica; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.565.2506; http://petrology.oxfordjournals.org/content/39/7/1285.full.pdf

that the Indian Ocean mantle domain may not greatly pre-date theThe isotopic difference between modern Indian Ocean and Pacific age of earliest spreading in the Indian Ocean.or North Atlantic Ocean ridge mantle (e.g. variably lower 206Pb/ 204Pb for a given eNd and 208Pb/204Pb) could reflect processes that occurred within a few tens of millions of years preceding the initial breakup of Gondwana. Alternatively, the Indian Ocean isotopic signature could be a much more ancient upper-mantle feature KEY WORDS: mantle geochemistry; old Indian Ocean; Tethyan crust inherited from the asthenosphere of the eastern Tethyan Ocean, which formerly occupied much of the present Indian Ocean region. Age-corrected Nd, Pb, and Sr isotopic data for 46–150 Ma seafloor Tethyan ophiolites (Masirah, Yarlung–Zangpo) reveal the presence of Isotopic studies of MORB (mid-ocean ridge basalts) have both Indian-Ocean-type compositions and essentially Pacific–North established the existence of a vast mantle domain in the Atlantic-type signatures. In comparison, Jurassic South Pacific Indian Ocean distinct from the sources of Pacific and ridge basalts from Alexander Island, Antarctica, possess normal North Atlantic MORB. Along the present Indian Ocean