Pluton, igneous rock

Fig. 3.14 Rb-Sr isochron defined by whole-rock samples of two Vanda Porphyry dikes (R1 and R2) and K-feldspar concentrates (FI and F2). The date of 460 7 Ma is the crystallization age of these dikes which were intruded into the metasedimentary rocks of the Asgard Formation, and into the plutonic igneous rocks of the Granite Harbor Intrusives in Wright Valley during the Middle Ordovician Epoch after the Ross Orogeny (Plotted from data by Jones and Faure 1967)...

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)...

Fig. 5.17 The plutons of Hope Granite that intruded the metasedimentary basement rocks of the Shackleton-Glacier area are collectively referred to as the Queen Maud batholith. The modal concentrations of Quartz (Q), alkali feldspar (A), and plagioclase (P) are used to classify a representative collection of the Hope Granite from this area (see also Fig. 3.21, Appendix 3.6.1). The distribution of data points indicates that the Hope Granite consists of granite (field 3), granodiorite (field 4), and quartz diorite (field 5) (Data by Wade and Cathey (1986) and classification of plutonic igneous rocks by Streckeisen (1967))...

Fig. 8.14 These silica variation diagrams support the conjecture that the Serpan Gneiss formed as a border facies of the magma of the Serpan Granite that was contaminated by assimilating rocks of the Patuxent Formation. Consequently, these bodies of plutonic igneous rocks have the same age but different Rb/Sr ratios. A straight line fitted to these samples in a Rb-Sr isochron diagram is a mixing line that cannot be used to calculate the age of these rocks. The chemical analyses of these rocks were provided by D.L. Schmidt to Eastin (1970)...

Halpern M (1966). Rubidium-strontium date from Mt. Byerly, West Antarctica. Earth Planet Sci Lett 1 455-457 Halpern M (1967) Rubidium-strontium isotopic age measurements of plutonic igneous rocks in eastern Ellsworth Land and northern Antarctic Peninsula, Antarctica. J Geophys Res 72 5133... 

The Plutonic igneous rocks are characterized by granular texture, massive structure and relatively homogeneous composition. In their unaltered state, they are essentially sound and durable with adequate strength for any engineering requirement (Table 5.28). In some... 

Slopes of excavations in fresh massive plutonic igneous rocks such as granite and gabbro can be left more of less vertical after removal of loose fragments. On the other hand, volcanic rocks such as basalt and andesite generally are bedded and jointed, and may contain layers of ash, which usually are softer and weather more rapidly. Thus, slope angles have to be reduced accordingly. 

Granite and to a lesser extent granodiorite are coarse grained plutonic igneous rocks (see Rocks and Meteorites for a precise petrological definition) primarily composed of silicate minerals such as quartz and feldspars often with small amount of accessory minerals such as... 

Mathews G. W. A classification of uranium deposits in and related to plutonic igneous rock. Reference 15, 15-21. 

Because the isotopic composition of igneous rocks is quite different from those of sedimentary rocks, studies of the isotope variations in the vicinity of an intrusive contact offer the possibihty of investigating the role of fluids interacting with rocks around cooling plutons. Two types of aureole can be distinguished (Nabelek 1991)... 

Bouse, R. M., Ruiz, J., Tidey, S. R., Tosdal, R. M., and Wooden, J. L. (1999). Lead isotope compositions of Late Cretaceous and Early Tertiary igneous rocks and sulfide minerals in Arizona Implications for the sources of plutons and metals in porphyry copper deposits. Econ. Geol. 94, 211-224. 

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