Origin of Garnet zoning in the contact metamorphic areole of Hassan-Abaad intrusion, southwest of Taft

In the contact metamorphic aureole of the next to the granodiorite intrusive body in the Hassan-Abaad village of Yazd, high frequency garnet in different metamorphic zones is notable, which some contain garnet crystal with obvious zoning. Obtained data from core to rim of garnet by SEM point analysis, show that garnet crystals belong to grandite series, and sharp variation of Al and Fe from center to rim indicates garnet zoning formed during crystal growth, but the zoning has been disturbed by fluid infiltration next to fractures. Researching on mineral variations from core to rim indicates that the main factor on the formation of oscillatory zoning was immiscibility in grandite series and followed by changes in hydrothermal solution composition.