Alkali granite

The mineralized district is restricted by two main strike-slip faults of Kubanan to the east and Posht e Bdam to the west (Fig. la). The host rocks are a thick sequence of Upper Precambrian-Cambrian rhyolite, tuff, alkali granite, syenite, mafic dykes, magnetitite, dolomite, gypsum, limestone, black shale, and sandstone. The Upper Percambrian-Cambrian sequence is overlain unconformably by Mesozoic and... 

In figure 8.2 the rocks with a composition as indicated by the shaded part are called alkali granite . The comers of this shaded area represent four mixtures whose compositions can be found in table 8.1. 

Fig. 3.21 The classification of plutonic igneous rocks by Streckeisen (1967, 1976) is based on the modal abundances of quartz (Q), alkali feldspar (including albite, An < 5%) (A), and plagioclase (An >5%) (P). The fields have been numbered in order to identify the rock types that correspond to them 1. quartz, 2. alkali granite, 3. granite, 4. granodiorite, 5a. quartz diorite (trondhjemite), 5b. quartz diorite (tonalite), 6. alkali syenite, 7a. quartz syenite, 7b. syenite, 8a. quartz monzonite (adamellite), 8b. monzonite, 9a. monzodiorite, 9b. monzogabbro, 10. diorite/gabbro (Adapted from Streckeisen 1967)...

The amli pluton is subalkaline and calc-alkaline, and mainly diorite porphyry, granodiorite, quartz monzonite, and granite-porphyry in composition (Fig. 3). The metadiabase is alkali basalt in composition,... 

Based on mineralogical and textural similarities (supported by geochemistry), the rocks of the syenitic dyke swarm can be subdivided into three groups (1) nepheline syenite - nephelinolite group (NS-N), (2) syenite - monzodiorite group (SM), and (3) an alkali feldspar granite dyke. 

The syenitic dyke swarm of the Moose Creek Valley can be subdivided based on mineralogy and geochemistry, into three groups SM, NS-N, and an alkali feldspar granite dyke. 

Watson E.B. and Jurewicz S.R. (1984) Behavior of alkalies during diffusive interaction of granitic xenoliths with basaltic magma. /. Geol. 92, 121-131. 

QUARTZ PORPHYRY. One of the hypabyssal or effusive rocks chemically related to the granite or alkali family but rich in silica, which occurs as quartz phenocrysts in a crypto or microcrystalline ground mass. 

Elba island 8.5-6.8 - Monzogranites and minor granodiorites, sieno-granites, alkali feldspar granites, aplites and pegmatites forming stocks, laccoliths, dykes and sills. Late (5.8 Ma) calc-alkaline mafic dike. 

The Gavorrano intrusive rocks consist of 4.9 to 4.3 Ma syenogranites, alkali-feldspar granites and monzogranites that are mostly hidden below... 

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