Petrology and geochemistry of the Eastern Loma de Cabrera Batholith, Dominican Republic
The Eastern Loma de Cabrera Batholith, located in the NW Cordillera Central, Dominican Republic, is a heterogeneous intrusive complex composed of a zoned ultramafic-mafic core surrounded by tonalite and diorite. The batholith intrudes metasbasaltic rocks of the Duarte Complex of early Cretaceous age. The ultramafic-mafic core consists of peridotite, olivine-pyroxenite, pyroxenite, and augite-hypersthene gabbro-norite. Pyroxenites and gabbro-norites exhibit large scale interlayering and small scale layering involving a regular variation in the proportions of ortho- and clinopyroxene. Tonalities and diorites are mafic to leucocratic, some being porphyritic. Petrographic types include hornblende, hornblende-pyroxene, hornblende-biotite, and muscovite-biotite types. Aplites are abundant. Intrusive relations suggest that ultramafic-mafic complex is the oldest intrusive phase, and was partially amphibolitized during later intrusion of the felsic rocks. Ultramafic-mafic rocks contain 43-54% SiO/sub 2/ and MgO ranges from 8-45%. Trace and REE in these rocks are relatively depleted. Tonalitic rocks range in SiO/sub 2/ from 53-76%, with K/sub 2/O varying from 0.15-2.9%. In addition, they are LREE enriched. A small Eu anomaly is best explained by fractionation of plagioclase and hornblende. Trends shown by Rb-Sr data suggest that fractional crystallization of hornblende and plagioclase, that is high level fractionation, is the important factor in controlling chemical variation in the tonalites.
- Research Organization:
- George Washington Univ., Washington, DC (USA)
- OSTI ID:
- 6874570
- 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 Oct 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DOMINICAN REPUBLIC
PLUTONIC ROCKS
CHEMICAL COMPOSITION
CRYSTALLIZATION
MINERALOGY
PETROLOGY
BIOTITE
FELDSPARS
FRACTIONATION
GEOCHEMISTRY
GEOLOGIC HISTORY
HORNBLENDE
ISOTOPE DATING
PYROXENES
AGE ESTIMATION
AMPHIBOLE
CHEMISTRY
DEVELOPING COUNTRIES
GEOLOGY
GREATER ANTILLES
HISPANIOLA
IGNEOUS ROCKS
ISLANDS
MICA
MINERALS
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
ROCKS
SEPARATION PROCESSES
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
WEST INDIES
580400* - Geochemistry- (-1989)
580300 - Mineralogy
Petrology
& Rock Mechanics- (-1989)
580100 - Geology & Hydrology- (-1989)