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Principles of Petrological Analysis of Igneous Rocks
Published in O.A. Bogatikov, R.F. Fursenko, G.V. Lazareva, E.A. Miloradovskaya, A. Ya, R.E. Sorkina, Magmatism and Geodynamics Terrestrial Magmatism Throughout the Earth’s History, 2020
The intrusive equivalents of the potassic moderately alkaline (shoshonite– latite) series are represented by subalkaline and gabbro–monzonite intrusions, recorded from the Kurile Islands and Japan (Tsvetkov, 1984). They make up the thick, sill-like bodies of the southern group of the Kuriles (Tanfilieva and Zeleny, etc.) and the Nemura Peninsula of Japan. They exhibit some layering features: from orthoclase-olivine gabbroids at the base, to monzonite, monzodiorite and syenite in the upper parts of the sills. Monzonite is the dominant rock type. Melt crystallization took place under near-surface conditions, as suggested by the spatial association with shoshonite lavas and pyroclastics.
Basaltic dykes and their xenoliths from the Gerroa–Kiama region, southern Sydney Basin, New South Wales: evidence for multiple intrusive episodes
Published in Australian Journal of Earth Sciences, 2022
S. Abu-Shamma, I. T. Graham, P. Lennox, G. Bann, A. Greig
The shoshonitic basaltic andesites (Five Islands, Bumbo and Calderwood latite members) are porphyritic, holocrystalline dark grey to black rocks. Phenocrysts comprise plagioclase, clinopyroxene, titanomagnetite and chlorite pseudomorphs after olivine (Carr, 1984). In some areas, the phenocrysts group together to form a glomeroporphyritic texture. The phenocryst-to-groundmass ratio varies from 1:1 to 1:9. Although some of these contain either vesicles or amygdales (lined with quartz, chlorite, hematite and laumontite), the vesicles and/or amygdales seldom surpass 10% by volume of rock. The groundmass displays a range of textures that vary from pilotaxitic, orthophyric, intergranular and more rarely intersertal. The primary groundmass phases consist of feldspar, clinopyroxene, apatite and titanomagnetite, whereas chlorite, hematite, calcite, sericite, kaolinite and epidote form the secondary minerals.