Four granite provinces have been delineated each with its own distinctive pattern of mineralization. 1. The Main Range Province. Endogenous greisen-bordered vein swarms of cassiterite and wolframite. 2. The Eastern Province. Magnetite–cassiterite skarns ± base metal sulphides with antimony in Thailand. 3. The Western (Peninsular Thailand–Burma) Province. Endogenous greisen-bordered vein swarms and pegmatites of cassiterite and wolframite. 4. The North Thailand Migmatitic Province. Endogenous vein and skarn replacement scheelite and fluorite deposits with some tin and local antimony. In all provinces, but particularly in the Main Range, granitoids designated as two-phase variants have been recognized where xenocrysts and xenoliths of coarse, primary texture granite are enclosed in, and corroded by an invasive, equigranular quartzo–feldspathic matrix. These rocks form an essential part of the granite sequence in all provinces and have probably resulted from the infiltration and disruption of the host granite by late stage magmatic fluids. Whole rock geochemistry from Peninsular Malaysia shows that the granites from the Main Range and Eastern Provinces comprise two contrasted suites which correspond approximately to the I and S-type categories advocated by Chappell & White (1974). In addition it is shown that individual plutons within batholiths in the two provinces have distinctive geochemical parameters. Variation diagrams of plutons having the intrusive sequence primary texture granite—two-phase granite—microgranite show linear trends with increasing SiO 2 , Na 2 O, Rb, W, Sn and U, and decreasing Sr, Ba, Th and all other major elements.

Pureora andesite volcano is sited at the junction of the Taupo Volcanic Zone with a line of andesite volcanoes extending from Ohakune to Waiheke Island.The lavas are porphyritic, with plagioclase, augite, and hypersthene the dominant phenocrysts. Chemically all samples may be classified as low-silica andesites, and both major and trace element contents are consistent with their derivation by crystal accumulation of pyroxene from a labradorite or labradorite-pyroxene andesite magma.

Textural evolution from coarse K-feldspar megacrystic granite, through heterogeneous granite porphyry to microgranite corresponds to a sequence of geochemical evolution. It was probably triggered by a sudden loss of pressure, resulting in quenching, fluidization, and disruptive emplacement of the residual melt into the partially or wholly crystalline host granite. It was accompanied by alkali metasomatism, volatile-fluxing, and hydrothermal alteration, culminating in the formation of greisen bordered vein swarms and massive greisens mineralized with tin and other metals.

Re-examination of the eastern and northern partsofthe Stong Complex has shown that there are three plutonic components. The earliest two phases are in part highly deformed in a manner similar to that of the marginal country rocks. The third phase, a distinctive set of pink granites. is underformed. Around the granitic rocks a contact aureole is developed in which the highest grade rocks are of low amphibolite facies. The numerous metasedimentary and metavolcanic enclaves within the granites have upper amphibolite facies mineralogy. Available evidence suggests that the intense dynamothermal metamorphism and deformation recorded in both sedimentary and some plutonic rocks resulted from forces generated by emplacement of the granitic rocks. At least the last part of the intrusive history of the Stong Complex took place in Late Cretaceous times; the age of the earlier phases is uncertain but lies within the time-frame Triassic to Late Cretaceous.

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