The Encantada Granite: registration of a peraluminous intrusion in the Rondonian Province - San Ignacio, in SW Amazonic Craton, Mato Grosso, Brazil
The Encantada Granite occurs on the extreme southwest of the state of Mato Grosso, SW of the Amazonian Craton, near the border of Brasil/Bolívia. It corresponds to an body oriented to NNW direction that intruded metasedimentary and metavolcanic rocks. It consists of leucogranites with monzo- to si...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Universidade de São Paulo
2015-06-01
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| Series: | Geologia USP. Série Científica |
| Subjects: | |
| Online Access: | http://ppegeo.igc.usp.br/pdf/guspsc/v15n2/a03v15n2.pdf |
| Summary: | The Encantada Granite occurs on the extreme southwest of the state of Mato Grosso, SW of the Amazonian Craton, near the
border of Brasil/Bolívia. It corresponds to an body oriented to NNW direction that intruded metasedimentary and metavolcanic rocks. It consists of leucogranites with monzo- to sienogranitic composition, marked by prominent schistosity. It is characterized by equigranular to porphyritic inequigranular texture, and composed of quartz, K-feldspar, plagioclase, muscovite and biotite with garnet, zircon, allanite and opaque minerals. Chlorite and epidote are the most common secondary minerals. The geochemical study allows the classification of the magmatism as having acid character, sub-alkaline, high-potassium-calc-alkaline to shoshonitic type. These rocks have alumina index saturation higher than 1, with normative corundum, and thus classified as peraluminous granite. Due to the reflection of the excess of aluminium, they have various aluminous phases, mainly muscovite, biotite and garnet; presents typical pattern of calc-alkaline rocks rich in potassium with enrichment of light ETRs over the heavy ones. The collected data allows to consider that the Encantada Granite rocks were generated from the partial melting of crustal rocks of pelitic composition. |
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| ISSN: | 1519-874X 2316-9095 |