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Tonalite is an igneous, plutonic rock, of felsic composition, with phaneritic (coarse-grained) texture. Feldspar is present as plagioclase (typically oligoclase or andesine ) with alkali feldspar making up less than 10% of the total feldspar content.
Tonalite–trondhjemite–granodiorite (TTG) rocks are intrusive rocks with typical granitic composition (quartz and feldspar) but containing only a small portion of potassium feldspar. Tonalite , trondhjemite , and granodiorite often occur together in geological records , indicating similar petrogenetic processes. [ 1 ]
In some literature, tonality is a generic term applied to pre-modern music, referring to the eight modes of the Western church, implying that important historical continuities underlie music before and after the emergence of the common practice period around 1600, with the difference between tonalité ancienne (before 1600) and tonalité ...
A greater amount of plagioclase would designate the rock as tonalite. Granodiorite is felsic to intermediate in composition. It is the intrusive igneous equivalent of the extrusive igneous dacite .
It is a relatively homogeneous mafic tonalite that consists primarily of plagioclase, quartz, hornblende, biotite and minor garnet, with small, cross-cutting felsic veins. [ 9 ] Lithology
Trondhjemite – Light-colored intrusive igneous rock – A form of tonalite where plagioclase-group feldspar is oligoclase; Tuff – Rock consolidated from volcanic ash; Websterite – Ultramafic and ultrabasic rock – A type of pyroxenite, composed of clinoproxene and orthopyroxene
Trondhjemite is a leucocratic (light-colored) intrusive igneous rock.It is a variety of tonalite in which the plagioclase is mostly in the form of oligoclase. [1] Trondhjemites that occur in the oceanic crust or in ophiolites are usually called plagiogranites.
Hooiberg is a Cretaceous-era tonalitic batholith that outcrops on Aruba consisting of tonalite with subordinate and comagmatic trondhjemite, diorite, gabbro, norite, and a dark-colored (melanocratic), hydrous, igneous rock termed hooibergite, or hornblende-rich mela-diorite.