Dark inclusions in the Nose pluton are usually fine-grained massive rocks with somewhat rounded shape. Under the microscope, they are diabasic to granoblastic texture, consisting essentially of pyroxene and plagioclase, accompanied with variable amount of amphibole, biotite and quartz. They occur frequently in mafic facies of the complex such as quartz diorite, and less frequently in adamellite.
Compositions of plagioclase and pyroxenes of dark inclusions are essentially similar to those ofthe host rocks. Moreover, major elements of the dark inclusions are similar to the quartz diorite. It is considered that orgin of these dark inclusions are concentrations of early crystallized minerals in the Nose dioritic magma.
Dark inclusion of the Myoken pluton has an occurrence like a dyke. Judging from the petrochemical and mineralogical evidences, it is considered that this dark inclusion is parts of rocks cogenetic with the Myoken granitic magma but older than it.
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