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
Granite outcrops of Western Australia as temporary protection against predation or seasonal habitat insulated from the extremes of weather. Granite outcrops occur along the southern coast of the state, where they are exposed to high winds and extremes and wave and tidal action. They often form steep coastline, headlands and islands. Granite outcrops of Western Australia Granite outcrops of Western Australia are weathered landforms that occur throughout the state of Western Australia, composed primarily of the rock type granite. All recognised types of this landform can be observed, commonly as bornhardts, but also as inselbergs, castle koppies and Nubbins. Rising abruptly from the surrounding landscape