Hydroxyl in continental deep subduction zone: Evidence from UHP eclogites of the Dabie Mountains

Infrared spectra in the region of 3 000 to 4 000 cm(-1) have been measured by an FTIR spectrometer on minerals in UHP eclogites from the Bixiling and Shuanghe areas, the Dabie Mountains. It is shown that omphacite is the most important hydrous mineral (100-200 mug/g) in UHP eclogites, Garnet and qua rtz contain virtually no H2O or OH. Accessory mineral rutile contains a sig nificant amount of OH (>1 000 mug/g). Coesite gives no indication of the pr esence of OH but apparent H2O bands. The results have considerable implicat ions for existing forms and contents of hydroxyl in the continental deep su bduction zone, the eastern Dabie Mountains.