1:45 PM - 3:15 PM
[O08-P28] Discovery of Oscillatory Zoned Structure Recording the Effects of Hydrothermal Solution from Dacite Amphibole
Keywords:hydrothermal solution, ion replacement, oscillatory zoned structure, magma differentiation
After the minerals crystallize from the magma, the hydrothermal solution circulates to form an oscillatory zoning structure in the minerals. The authors discovered for the first time the oscillatory zoned structure of amphibole that constitutes the phenocrysts of dacite distributed in the Sanyo belt in the southern part of Hyogo prefecture, which was active from the late Cretaceous to the Paleogene. Not found in basalt.
The oscillatory zoned structure is an index for estimating what kind of ion replacement and how much is performed between the first crystallized amphibole and the subsequent circulating hydrothermal solution. The formation of an oscillatory zoned structure of the amphiboles of the dacite, which is a volcanic rock, indicates that the hydrothermal solution circulated in a very short time.
Since it is not found in basalt amphibole, it is presumed that the circulation of hydrothermal solution does not occur in the early stage of magma differentiation.
The oscillatory zoned structure is an index for estimating what kind of ion replacement and how much is performed between the first crystallized amphibole and the subsequent circulating hydrothermal solution. The formation of an oscillatory zoned structure of the amphiboles of the dacite, which is a volcanic rock, indicates that the hydrothermal solution circulated in a very short time.
Since it is not found in basalt amphibole, it is presumed that the circulation of hydrothermal solution does not occur in the early stage of magma differentiation.