Origin of the Indian Ocean-type isotopic signature in basalts from Philippine Sea plate spreading centers; an assessment of local versus large-scale processes

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doi: 10.1029/98JB02052
Author(s): Hickey-Vargas, Rosemary
Author Affiliation(s): Primary:
Florida International University, Department of Geology, Miami, FL, United States
Volume Title: Journal of Geophysical Research
Source: Journal of Geophysical Research, 103(B9), p.20,963-20,979. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0148-0227
Note: In English. 81 refs.; illus., incl. 1 table, sketch map
Summary: Basalts erupted from spreading centers on the Philippine Sea plate between 50 Ma and the present have the distinctive isotopic characteristics of Indian Ocean mid-ocean ridge basalt (MORB), such as high 208Pb/204Pb and low 143Nd/144Nd for a given 206Pb/204Pb compared with Pacific and Atlantic Ocean MORB. This feature may indicate that the upper mantle of the Philippine Sea plate originated as part of the existing Indian Ocean upper mantle domain, or, alternatively, that local processes duplicated these isotopic characteristics within the sub-Philippine Sea plate upper mantle. Synthesis of new and published isotopic data for Philippine Sea plate basin basalts and island arc volcanic rocks, radiometric ages, and tectonic reconstructions of the plate indicates that local processes, such as contamination of the upper mantle by subducted materials or by western Pacific mantle plumes, did not produce the Indian Ocean-type signature in Philippine Sea plate MORB. It is more likely that the plate originated over a rapidly growing Indian Ocean upper mantle domain that had spread into the area between Australia/New Guinea and southeast Asia before 50 Ma. Copyright 1998 by the American Geophysical Union.
Year of Publication: 1998
Research Program: DSDP Deep Sea Drilling Project
Key Words: 02 Geochemistry; 05 Petrology, Igneous and Metamorphic; Basalts; Cenozoic; Chemical composition; Deep Sea Drilling Project; Eruptions; Igneous rocks; Island arcs; Isotope ratios; Isotopes; Lead; Mantle; Mariana Trough; Metals; Mid-ocean ridge basalts; Nd-144/Nd-143; Neodymium; North Pacific; Northwest Pacific; Pacific Ocean; Pb-208/Pb-204; Petrography; Philippine Sea; Philippine Sea Plate; Plate tectonics; Radioactive isotopes; Rare earths; Samples; Sea-floor spreading; Spreading centers; Stable isotopes; Tectonics; Upper mantle; Volcanic rocks; Volcanism; West Pacific
Coordinates: N100000 N300000 E1480000 E1300000
Record ID: 1999011622
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