Strontium isotopic evidence for an enriched source for post-subduction volcanic rocks, Dominican Republic
Later Cenozoic volcanic rocks from the eastern Las Cuevas region (ELCR), Dominican Republic are dominantly shoshonitic and are associated with a series of east-west trending faults. The ELCR rocks are highly enriched in Sr, Ba, and light REE, but contain relatively low amounts of Rb and HFS ions. Several basalts appear to be unfractionated and have Mg-numbers of >75. These transitional to alkalic volcanic rocks are atypical of Caribbean igneous rocks and are more similar to alkaline centers associated with late-stage, island arc volcanism in other regions. Elevated /sup 87/Sr//sup 86/Sr ratios (0.7041-0.7048) are high in comparison to most other igneous rocks from the Caribbean region and indicate that they were derived from a source relatively enriched in LIL and REE in comparison to the sources which gave rise to the majority of Caribbean igneous rocks. /sup 87/Sr//sup 86/Sr values increase linearly with increasing Sr contents, suggesting mixing of sources with relatively low Sr contents and depleted /sup 87/Sr//sup 86/Sr with material that is highly enriched in Sr and with /sup 87/Sr//sup 86/Sr values around 0.706. This enriched component may be a fluid derived from melting/dehydrating subducted oceanic crust and sediment which metasomatically veined the sub-arc mantle. Small degrees of partial melting (<7%) of this source may be responsible for the unusual and enriched chemical composition of the ELCR volcanic rocks.
- Research Organization:
- Univ. of Florida, Gainesville (USA)
- OSTI ID:
- 6031623
- Report Number(s):
- CONF-8510489-
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28-31 Oct 1985
- Country of Publication:
- United States
- Language:
- English
Similar Records
Petrology and Sr and Nd isotopic characteristics of five late Cretaceous-early Tertiary volcanic fields in western Alaska
Origin of Paleozoic volcanics, northern Sierra Nevada, California: trace element and isotopic evidence
Related Subjects
DOMINICAN REPUBLIC
VOLCANIC ROCKS
CHEMICAL COMPOSITION
PETROGENESIS
BARIUM
GEOCHEMISTRY
GEOLOGIC FAULTS
ISOTOPE RATIO
OCEANIC CRUST
RARE EARTHS
STRONTIUM
STRONTIUM ISOTOPES
SUBDUCTION ZONES
VOLCANIC REGIONS
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
CHEMISTRY
DEVELOPING COUNTRIES
EARTH CRUST
ELEMENTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GREATER ANTILLES
HISPANIOLA
IGNEOUS ROCKS
ISLANDS
ISOTOPES
METALS
ROCKS
WEST INDIES
580400* - Geochemistry- (-1989)
580300 - Mineralogy
Petrology
& Rock Mechanics- (-1989)