Application of multivariate analysis in the exploration for tin in granites: a study of granites from northwestern tanzania using discriminant function and factor analysis

J.R. IKINGURA, Department of Geology, University of Dar es Salaam, TanzaniaFollow

Section

Physical Sciences

Abstract

Variations in major and trace element Composition of granites from Karagwe-Ankolean (NE Kibaran) belt in northwestern Tanzania have been investigated by factor analysis and discriminant function statistical methods, The variations are attributed to three main factors. Factor 1 is positively loaded with CaO, MgO, Fe₂O₃ (Fe total), TiO₂, MnO, Ba, Sr, Zr and Y, and negatively loaded with P₂O₅, SiO₂, B and Rb. Factor 2 is positively loaded with Na2O, P₂O₅ Mno, Sn, Li, Rb and Y, and negatively loaded with TiO₂, K₂O, Ba, Sr and Zr. Factor 3 is positively loaded with Al₂O₃. MnO, P₂O₅, Fe₂O₃, Nb, F and Rb, and negatively loaded with SiO₂. Factor 1 is considered to indicate fractional crystallization of mafic minerals and plagioclase from original magmas while factor 2 indicates albitization and Sn-enrichment in the granites. Factor 3 is thought to indicate F-metasomatism and muscovitimtion of the granites. The majority of tin granites (85%) in the Karagwe-AnkoIean belt can be discriminated from the barren granites using the discriminant functions: DF1 = 0.70630Na₂0 – 0.50776CaO - 0.3800MgO - 3.79034 and DF2 = 0.01972Y - 0.02239Zr – 0.01326Zn – 0.04670K/Rb + 6.19790. These results suggest that multivariate analysis of lithochemical data can be used as an exploration tool for tin granites.

Recommended Citation

IKINGURA, J.R. (1995) "Application of multivariate analysis in the exploration for tin in granites: a study of granites from northwestern tanzania using discriminant function and factor analysis," Tanzania Journal of Science: Vol. 21: Iss. 1, Article 4.
Available at:https://doi.org/10.65085/2507-7961.2422