Geochemistry and Petrography of Alkaline rocks from Monte Santo Alkaline Intrusive Suite, Western Araguaia Belt, Tocantins State, Brazil

DOI: 10.4236/gep.2014.23010   PDF   HTML     5,119 Downloads   6,381 Views   Citations


The Monte Santo Alkaline Intrusive Suite (MSAIS) is an association syenite foid, nepheline syenite and syenite. The MSAIS rocks are intruded in metapelites of the Rio do Coco meta-volcanic-sedi- mentary Sequence and are abundant pegmathoid veins cutting all of them. The mineral paragenesis is represented by aegirina, arfvedsonite, albite and nepheline, crystallized during the initial phase of crystallization. A late magmatic phase show nepheline, perthite, calcite and biotite, and a hydrothermal phase allowed for the formation of cancrinite, sodalite, analcime and natrolita associated with altered nepheline. The geochemical analyses showed metaluminous and medium to high potassium characteristics, being classified as miaskitic rocks, according to agpaicity and the Na + K > 1/6Si indexes. However, the mineralogical assemblage suggests a low to medium agpaitic composition, which can be related to a transition from miaskitic to agpaitic crystallization regime. The rare earth elements showed depletion in heavy rare earth and a strong negative Eu anomaly and enrichments in the some lithophile elements, suggesting a differentiated pattern later, which can be associated to metasomatic alterations.

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Viana, R. and Battilani, G. (2014) Geochemistry and Petrography of Alkaline rocks from Monte Santo Alkaline Intrusive Suite, Western Araguaia Belt, Tocantins State, Brazil. Journal of Geoscience and Environment Protection, 2, 72-79. doi: 10.4236/gep.2014.23010.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Almeida, F. F. M., Hasui, Y. and Brito Neves, B. B., & Fuck R. A. (1977). Províncias Estruturais Brasileiras. In: VIII Simpósio de Geologia do Nordeste, Campina Grande. Atas. Pernanbuco, SBG-Núcleo Nordeste, 1, 363-392.
[2] Bates, R. L., & Jackson, J. A. (1980). Glossary of Geology. AGI, Falls Church, 751 p.
[3] Shand, S. J. (1922). The Problem of the Alkaline Rocks. Proceedings of the Geological Society of South Africa, 25, 19-33.
[4] Blichert-Toft, J., Arndt, N. T., & Ludden J. N. (1996). Precambrian Alkaline Magmatismo. Lithos, 37, 97-111.
[5] Bonin, B., Azzouni-Sekkal, A., Bussy, F., & Ferrag, S. (1998). Alkali-Calcic and Alkaline Post-Orogenic (PO) Granite Magmatism: Petrologic Contraints and Geodynamic Setting. Lithos, 45, 45-70.
[6] Carmichael, I. S. E, Turner, F. J., & Verhoogen, J. (1974). Igneous Petrology. McGraw-Hill, New York
[7] Ulbrich, H.H. (1984). A Petrografia, a Estrutura e o Quimismo de Nefelina Sienitos do Maci?o Alcalino de Po?os de Caldas, MG-SP. Ph.D. Dissertation, Inst. De Geociências, Univ. S?o Paulo, 477 p.
[8] Cunha, B. C. C., Potiguar, L. A. T., Lanhez, A. C., Bezerra, P. E. L., Pitham, J. H. L., Souza, Jr., J. J., & Tassinari, C. C. G. (1981). Geologia, Geomorfologia, Pedologia, Vegeta??o r uso potencial da Terra. Brasil. Projeto RADAMBRASIL. Folha SC.22 Tocantins. Rio de Janeiro, (Levantamento de Recursos Naturais, 22), 21-196.
[9] Fall, A. (2005). Fluid Evolution in the Nepheline Syenites of the Ditr?u Alkaline Massif, Transylvania, Romania. Ph.D. Dissertation, Blacksburg, Virginia, Faculty of the Virginia Polytechnic Institute and State University.
[10] Fall, A., Bodnar, R.J., Sszab?, C. and Pal-Moln?r, E. (2007). Fluid Evolution in the Nepheline Syenites of the Ditrau Alkaline Massif, Transylvania, Romania. Lithos, 95, 331-345.
[11] Fitton, J. G., & Upton, B. G. (1987). Alkaline Igneous Rocks. Geol. Soc. Spec. Publ. 30. 568 p.
[12] Frasca, A. A .S., & Araújo, V. A. (2001). Projeto Hidrogeologia no Tocantins—Folha Palmas—SD 22-Z-B. CPRM/Servi?o Geológico do Brasil, Goiania, 52 p.
[13] Frost, B. R., & Frost, C. D. (2008). A Geochemical Classification for Feldspathic Igneous Rocks. Journal of Petrology, 49, 1955-1969.
[14] Fuck, R. A., Dantas, E. L., Pimentel, M. M., Junges, S. L., & Moraes, R. (2001). Nd Isotopes, U-Pb Single Grain and SHRIMP Zircon Ages from Basement Rocks of the Tocantins Province. Proceedings of the III South American Symposium on Isotope Geology, Extended Abstract, Santiago, 141-144 (CD ROM).
[15] Iwanuch, W. (1991). Geologia dos complexos alcalinos proterozóicos do centro do estado de Tocantins. Ph.D. Dissertation, Instituto de Geociências, Universidade de S?o Paulo, S?o Paulo.
[16] Khomyakov, A. P. (1995). Mineralogy of Hyperagpaitic Alkaline Rocks (p. 223). Oxford: Clarendon Press.
[17] Le Maitre, R. W. (2002). Igneous rocks a Classification and Glossary of Terms Recommendations of the International Union of Geological Sciences, Sub-Commission on the Systematics of Igneous Rocks, Cambridge University Press, 236 p.
[18] Mantovani, M. S. M., & Brito Neves, B. B. (2005). The Paranapa-nema Lithospheric block: Its Importance for Proterozoic (Rodinia, Gondwana) Supercontinent theoRies. Gondwana Research, 8, 303-315.
[19] Marcheto, C. M. L. (1973). Nota Sobre a Ocorrência de um Litechfieidito no Morro da Estrucei, Município de Porto Nacional, Goiás. Congresso Brasileiro de Geologia, Resumo das Comunica??es. Soe. Bras. Geologia, Bol. 1, pp. 85-86.
[20] Marks, M. A. W., Hettmann, K., Schilling, J., Frost, B. R., & Markl, G. (2011). The Mineralogical Diversity of Alkaline Igneous Rocks: Critical Factors for the Transition from Miaskitic to Agpaitic Phase Assemblages. Journal of Petrology, 52, 439-455.
[21] McDonough, W. F., & Sun, S.-S. (1995). The Composition of the Earth. Chemical Geology, 120, 223-253.
[22] Middlemost, E. A. K. (1975) The Basalt Clan. Earth Science Reviews, 11, 337-364.
[23] Middlemost, E. A. K. (1985). Magmas and Magmatic Rocks. Longman Group Limited, Essex, UQ.
[24] Mitchell, R. H. (1996). Perovskites: A Revised Classification Scheme for an Important Rare Earth Element Host in Alkaline Rocks. In Jones, A. P., Wall, F., & Williams, C. T. (Eds.), Rare Earth Minerals: Chemistry, Origin and Ore Deposits (pp. 41-76). London: Chapman & Hall.
[25] Streckeisen, A., & Hunziker, I. C. (1974). Schweiz. Mineral. Petr. Mitt., 54, 59-77.
[26] Nakamura, N. (1974). Determination of REE, Ba, Fe, Mg, Na, and K in Carbonaceous and Ordinary Chondrites. Geochimica et Cosmochimica Acta, 38, 757-775
[27] Pearce, J. A., Harris, N. B. W., & Tindle, A. J. (1984). Trace Element Discrimination Diagrams for the Tectonic Interpretation of Granitic Rocks. Journal of Petrology, 25, 956-83.
[28] Pimentel, M. M., Fuck, R. A., Jost, H., Ferreira Filho, C. F., & Araújo, S .M. (2000). The Basement of the Brasília Fold Belt and the Goiás Magmatic Arc. In: Cordani, U. G., Milani, E. J., Thomaz Filho, A. and Campos, D. A. (Eds.), Tectonic Evolution of South America (pp. 190-229), Rio de Janeiro: 31st IGC.
[29] S?rensen, H. (1974). Alkali Syenites, Feldspathoidal Syenites and Related Lavas. In Sorense, H. (Ed.), The Alkaline Rocks (pp. 22-52), London: John Wiley & Sons.
[30] Sorensen, H. (1997). The AGPAITIC rocks—An Overview. Mineralogical Magazine, 61, 485-498.

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