Nd and Sr isotopic signatures of Mesozoic plutons in northeastern North America
Nd and Sr initial isotope ratios are reported for 17 Mesozoic plutons of the Monteregian Hills and White Mountain series provinces in northeastern North America. Some variation in the isotopic ratios at most localities is caused by crustal-contamination processes. When the crustal assimilation effects are taken into account, the initial ratios for apparently uncontaminated, mantle-derived parental magmas show only restricted range in /sup 87/Sr//sup 86/Sr (0.7032 to 0.7040) and epsilon/sub Nd/ (T) (+5.4 to +2.3), which are inversely correlated. These ratios characterize alkaline to subalkaline magmas emplaced over more than 400 km/sup 2/ and about 80 m.y. The isotopic and trace-element characteristics are broadly similar to those of many modern ocean-island basalts, specifically the New England Seamounts, suggesting similar time-integrated, lithophile-element-depleted mantle sources. The results are consistent with plume-related mantle sources deeper than the subcontinental mantle.
- Research Organization:
- Ohio State Univ., Columbus (USA)
- OSTI ID:
- 6765055
- Journal Information:
- Geology; (United States), Vol. 16:8
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NORTH AMERICA
PLUTONIC ROCKS
AGE ESTIMATION
GEOLOGIC HISTORY
ISOTOPE RATIO
MAGMA
MESOZOIC ERA
NEODYMIUM ISOTOPES
STRONTIUM 86
STRONTIUM 87
ALKALINE EARTH ISOTOPES
BETA DECAY RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
GEOLOGIC AGES
HOURS LIVING RADIOISOTOPES
IGNEOUS ROCKS
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
NUCLEI
RADIOISOTOPES
ROCKS
STABLE ISOTOPES
STRONTIUM ISOTOPES
580100* - Geology & Hydrology- (-1989)