Garnet-forming dehydration reactions and fluid migration in subduction zone

Abstract

Fluids released from dehydration reactions are thought to rise pore fluid pressure within subduction zone; however, little evidence has not been reported from metamorphic rocks. We report skeletal garnet in metachert, which contains large amount of quartz inclusions. The microstructural observations suggest grain-boundary cracking induced by dehydration. By using a model with distinct element method, the conditions and mechanism of reaction-induced fracturing and fluid flow are discussed.