Granite may have more alkali feldspar, whereas a granite derived from partial melting of metaigneous rocks may be richer in plagioclase. It is on this basis that the modern "alphabet" classification schemes are based. The letter-based Chappell & White classification system was proposed initially to divide granites into I-type (igneous source) granite and S-type (sedimentary sources). Both types are produced by partial melting of crustal rocks, either metaigneous rocks or metasedimentary rocks. M-type granite was later proposed to cover those granites that were clearly sourced from crystallized mafic magmas, generally sourced from the mantle. However, this proposal has been rejected by
Kokerbin Rock the summit are accessible by marked bush walks. The rock formations include a wave rock formation, Dog Rock and Devil's Marbles. On the western side of Kokerbin Rock is a historic stone well and an old school site, remainders of early European settlement. <mapframe text="Kokerbin Rock is located within the Kokerbin Nature Reserve" width=300 height=300 zoom=15 latitude=-31.88772 longitude=117.70484>{ "type": "ExternalData", "service": "geoshape", "ids": "Q16893567", }</mapframe> Kokerbin Rock Kokerbin Rock, also known as Kokerbin Hill, is a granite rock formation located within the Kokerbin Nature Reserve in the Wheatbelt region of Western Australia. The area has special significance for Noonga. There