Sources of island arcs as indicated by Nd and Sr isotopic studies
Island arc lavas from New Britain and the Marianas have /sup 143/Nd//sup 144/Nd similar to other oceanic basalts and distinctly different from continental flood basalts and thus appear to be derived from a high Sm/Nd, light-REE-depleted reservoir. Consideration of both Nd and Sr isotopes suggests seawater involvement in the generation of some island arc lavas and thus indicates that they may be derived from altered subducted oceanic crust. Other island arc lavas show no evidence of seawater involvement and may be derived from mantle reservoirs with affinities to the sources of ocean island basalts. Andesite and rhyolite from an Andean volcano reflect assimilation of old continental crust. Nd and Sr in basaltic and ultrapotassic continental rocks indicate that some mafic magmas in continental regions may be derived from old low-Sm/Nd reservoirs or are heavily contaminated with old continental crustal material. Fish debris from the ocean floor provides an estimate of /sup 143/Nd//sup 144/Nd in seawater and indicates that light-REE in the marine environment are derived mainly from continents. Basalts erupted above sea level in oceanic and continental areas are isotopically distinct from those erupted on the ocean floor, suggesting a relationship between parental reservoirs and hydrostatic head.
- Research Organization:
- The Lunatic Asylum, Div. of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125
- OSTI ID:
- 7287741
- Journal Information:
- Geophys. Res. Lett.; (United States), Vol. 4:10
- Country of Publication:
- United States
- Language:
- English
Similar Records
O-, Sr-, Nd-isotope, and trace element relationships in lavas from Mount Shasta in northern California
Isotopic and chemical constraints on the petrogenesis of Blackburn Hills volcanic field, western Alaska
Related Subjects
LAVA
ORIGIN
ROCK-FLUID INTERACTIONS
ANDESITES
BASALT
ISLANDS
ISOTOPE RATIO
MAGMA
NEODYMIUM 143
NEODYMIUM 144
SEAWATER
STRONTIUM 86
STRONTIUM 87
ALKALINE EARTH ISOTOPES
ALPHA DECAY RADIOISOTOPES
BETA DECAY RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
HOURS LIVING RADIOISOTOPES
HYDROGEN COMPOUNDS
IGNEOUS ROCKS
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
NEODYMIUM ISOTOPES
NUCLEI
OXYGEN COMPOUNDS
RADIOISOTOPES
RARE EARTH NUCLEI
ROCKS
STABLE ISOTOPES
STRONTIUM ISOTOPES
VOLCANIC ROCKS
WATER
YEARS LIVING RADIOISOTOPES
580202* - Geophysics- Volcanology- (1980-1989)