S Type Granite Classification

Both s and i type are dominantly magnesian but like the mesozoic batholiths of western north america fig.

S type granite classification. S type granite this type is of sedimentary origin paraorigin from anatexis of sedimentary rocks with high al2o3 and low sio2 content ex. Epizonal granite mesozonal granite catazonal granite buddington s depth zones chemical classification table 18 3. 4 a considerable population of the. They are characterised by low water and a lack of tectonic fabric.

Other articles where i type granite is discussed. A stands for anorogenic or anhydrous. Amphibole and pyroxene are more common in i type granitoids. Garnet is a very common accessory mineral in this type.

In our classification the s type granitoids of the lachlan fold belt are compositionally similar to the i type. S type granites are over saturated in aluminium with an asi index greater than 1 1 where asi al 2 o 3 cao na 2 o k 2 o in mol percent. I type granitoids are dominantly calc alkalic and calcic. Tectonic setting is arc collision.

Magma type is usually peraluminous magma al2o3 na2o k2o cao. Amphibole and pyroxene are more common in i type granitoids while s type granitoids may have garnet cordierite and sillimanite. The clear differences between mags and peralkaline granites patiño douce 1999 require a refined classification of these two a type granite groups. Patiño douce s criteria to distinguish strongly peraluminous topaz rhyolites from mags are less evident not least in view of the fact that topaz bearing granites similar in mineralogy and.

S i a m classification chappell and white s type granites i type granites a type granitoids m type granitoids s type granites occur in regional metamorphic terranes partial melting of metasediments high al but contain no hornblende biotite muscovite cordierite garnet high rb in source rocks. These result in i type granitoids derived from igneous protoliths and containing moderate amounts of al2o3 and high amounts of na2o and s type granitoids derived from sedimentary protoliths and containing high amounts of al2o3 and relatively low amounts of na2o. The granite class was proposed by loiselle and wones in 1979. The s i a m classification of granitoids type sio 2 k 2o na 2o ca sr a c n k fe 3 fe2 cr ni δ18o 87sr 86sr misc petrogenesis m 46 70 low high low low low 9 0 705 low rb th u subduction zone low lil and hfs or.

Other articles where s type granite is discussed. High amounts of na2o and s type granitoids derived from sedimentary protoliths and containing high amounts of al2o3 and relatively low amounts of na2o. A type granites are a class of granite. Petrographic features are representative of the chemical.

A principally new discriminant diagram is proposed for the classification of igneous a type rocks based on the analysis of earlier obtained results and the petrochemical composition of these.