Seyed Ali Mazhari
Abstract
Naqadeh intrusive pluton is composed of two distinct sections of felsic (40 Ma age) and mafic (99 Ma age) rocks. The granitoid rocks of Naqadeh pluton have different types of mafic ...
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Naqadeh intrusive pluton is composed of two distinct sections of felsic (40 Ma age) and mafic (99 Ma age) rocks. The granitoid rocks of Naqadeh pluton have different types of mafic enclaves, including mafic microgranular enclaves (MME) and quartz + amphibole bearing enclaves. The MME has the same age to its host granitoids and could be divided into two types. The first type has similar Sr-Nd composition to the host rock (87Sr/86Sri = 0.7062 and εNdi= -0.89), and their trace amphibole composition is like host granitoids. These enclaves are cogenetic with the granitoid magma and formed by early crystal-melt segregations. Another type of MME shows the textural evidence of magma mixing and is characterized by different isotopic ratios from granitoids (87Sr/86Sri = 0.7042 and εNdi= +2.98). The trace element composition of this type of enclave is completely different from the other enclaves and the host rocks. The quartz + amphibole bearing enclave formed contemporaneous with mafic rocks of Naqadeh pluton (99 Ma), and displays the same isotopic ratios and amphibole composition.
