Potassic/ultrapotassic magmatism pos a tardi-orogenic (associated to subduction) in the western of Bahia: batolite monzo-syenitic from Guanambi-Urandi and the syenites from Correntina, Brazil
Creators
- 1. Bahia Univ., Salvador, BA (Brazil). Inst. de Geociencias
- 2. Sao Paulo Univ., SP (Brazil). Inst. de Geociencias
Description
The western portion of Bahia State is characterized by polimetamorfic rocks (granulites and gneissic-migmatitics) intruded by great volume of undeformated monzonitic and syenitic rocks. Tectonically, this region is interpreted as an Early Proterozoic mobile belt. Clynopiroxene-syenitic rocks are more conspicuous in the western side of the Sao Francisco river (Correntina Syenites), while amphibole-mica monzonitic and syenitic rocks (Guanambi-Urandi Batholith) occur southeastward. The Guanambi-Urandi, a 6000 km2 batholith, shows a slight sigmoidal shape whereas the Correntina Syenites outcrop along the valleys where the Phanerozoic cover difficults the mapping. The existing geochronological data reveal a contemporaneity between these set of rocks, about 2 Ga. Our geochemical data point to potassic plutonism, with high Ba, Sr, REE and moderate Ti, Zr, Nb and Y. The above characteristics suggest an orogenic environment, probably linked a subduction zone. (author)
Additional details
Additional titles
- Original title (Portuguese)
- Magmatismo potassico/ultrapotassico pos a tardi orogenico (associado a subduccao) no oeste da Bahia: batolito monzo-sienitico de Guanambi-Urandi e os sienitos de Correntina
Publishing Information
- Journal Title
- Geochimica Brasiliensis
- Journal Volume
- 10
- Journal Issue
- 1
- Journal Page Range
- p. 27-42
- ISSN
- 0102-9800
- CODEN
- GEBREK
INIS
- Country of Publication
- Brazil
- Country of Input or Organization
- Brazil
- INIS RN
- 30009750
- Subject category
- S58: GEOSCIENCES; S37: INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY;
- Descriptors DEI
- ARGON ISOTOPES; BRAZIL; CHEMICAL ANALYSIS; GEOCHEMISTRY; ISOTOPE DATING; MAGMATISM; PETROGRAPHY; PLUTONIC ROCKS; POTASSIUM ISOTOPES; RUBIDIUM 87; STRONTIUM 86; STRONTIUM 87; SYENITES
- Descriptors DEC
- AGE ESTIMATION; ALKALINE EARTH ISOTOPES; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; DEVELOPING COUNTRIES; ELECTRON CAPTURE RADIOISOTOPES; EVEN-EVEN NUCLEI; EVEN-ODD NUCLEI; GEOLOGY; HOURS LIVING RADIOISOTOPES; IGNEOUS ROCKS; INTERMEDIATE MASS NUCLEI; ISOMERIC TRANSITION ISOTOPES; ISOTOPES; LATIN AMERICA; NUCLEI; ODD-EVEN NUCLEI; PLUTONIC ROCKS; RADIOISOTOPES; ROCKS; RUBIDIUM ISOTOPES; SOUTH AMERICA; STABLE ISOTOPES; STRONTIUM ISOTOPES; YEARS LIVING RADIOISOTOPES
Optional Information
- Notes
- 62 refs., 7 figs., 2 tabs.