S Type Granite Mineralogy

Granite is an intrusive igneous rock which means that it s formed by magma slowly cooling below the surface of the earth.

S type granite mineralogy. S type granite this type is of sedimentary origin paraorigin from anatexis of sedimentary rocks with high al2o3 and low sio2 content ex. Hornblende is common in the more mafic i types and is generally present in the felsic types also. 1 lecture 25 granites wednesday may 4th 2005 chapters 17 18. And soda granite s type can be considered as source for cu u and mo and metavolcanic rocks as source for cu ni co te bi and au sarkar 1982 1984.

If they are generated from different continental settings and from different magma so can we see. Magma type is usually peraluminous magma al2o3 na2o k2o cao. In the felsic s types hornblende is absent but muscovite is common while in the mafic s types biotite is often very abundant. Tectonic setting is arc collision.

Granite is the most common intrusive rock in earth s continental crust it is familiar as a mottled pink white gray and black ornamental stone it is coarse to medium grained. Mineralogy primary minerals present in the magma during crystallization major minerals present in amounts 5 volume like all granites the modal mineralogy of s type granites are dominated by alkali and plagioclase feldspars and quartz thus s type granites are silica over saturated contain quartz and do not contain feldspathoids an interesting feature of s type granites at the hand. True granite is a mixture of several different minerals including quartz mica silica feldspar and other trace minerals that lend different colors to the stone. I type granites have less quartz then their s type granite color index equivalents.

Both s and i type are dominantly magnesian but like the mesozoic batholiths of western north america fig. Rao and rao 1983a b. Primary minerals in i type granites are plagioclase potassium feldspar and quartz like s and a type granites. Granitoid rocks granitoids sensu lato.

Some of the geochemical aspects of s and i type granitoids are reflected in the mineralogy. 4 a considerable population of the. In our classification the s type granitoids of the lachlan fold belt are compositionally similar to the i type. I type granitoids are dominantly calc alkalic and calcic.

Garnet is a very common accessory mineral in this type. Loosely applied to a wide range of felsic plutonic rocks granite sensu stricto granodiorite tonalite associated volcanics occur and have same origin but are frequently eroded away. Potassium feldspar can show perthite textures carlsbad twinning and in microcline tartan twinning.