Home – Home – Jornals – Russian Geology and Geophysics 2001 number 5

The composition of minerals and rocks of the Arban granulite massif has been studied. The massif is a tectonic block among stratified volcanometasedimentary deposits of the Onot greenstone belt (Sharyzhalgai protrusion of the Siberian Platform). According to mineral and chemical compositions two types of basic granulites are recognized: leucocratic, close in contents of major and trace elements to low-titanium tholeiitic basalts, and melanocratic, depleted in SiO₂, Na₂O, Rb, Ba, Sr, and LREE and enriched in Fe₂O₃, Ti, Nb, HREE, Y, and Sc (compared with the leucocratic granulites) and compositionally similar to restite equilibrated with tonalite melt. Acid plagiogranulites are compositionally close to high-alumina tonalite-trondjemites forming from a metabasic source at P 12