Petrology
haleh ghorbani; robab hajialioghli; mohsen moazzen
Abstract
The Ghareh naz migmatites were formed as a result of partial melting of amphibolites under granulite facies conditions. Structeral, textural, mineralogical and geochemical evidence in the migmatites migmatites indicates their formation via partial melting during partial melting. The studied migmatites ...
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The Ghareh naz migmatites were formed as a result of partial melting of amphibolites under granulite facies conditions. Structeral, textural, mineralogical and geochemical evidence in the migmatites migmatites indicates their formation via partial melting during partial melting. The studied migmatites have a variety of structures including patchy, scholen, ophthalmitic, stromatic, diktyonitic, ptygmatic, phlebetic, schliren, pegmatitoid and nebulitic. The presence of striated plagioclases and amorphous quartzes along with granular texture, myrmecite and peritite in the locosome parts as well as the presence of zoning, polysynthetic twin in the plagioclases indicate a partial melting role in the formation of migmatites. Based on mass balance calculations in the ghareh naz migmatites, the parts of the migmatite components of the locosome, melanosome, and mesosome are aligned in a straight line, indicating a partial melting source of the studied migmatites.The percentage of partial melting for the studied megmatites was calculated to be about 36.5% and 43.6%,respectively. The difference in partial melting percentages may depend on the relationship between the rate and melt outflow and to a small extent on the amount of melt in the region. The formation temperature of these migmatites is determinated about 850-850 ° C and the pressure is about 6-7 kbar.
