Therearefourunitsofhigh-pressuretoultrahigh-pressuremetamorphismextendingfromsouthtonorthacrosstheTongbai-DabieMountains:theepidote-blueschist-faciesunit,thelow-temperatureeclogitefaciesunit,theultrahigh-pressureeclngitefaciesunitandthemedium-temperatureeclogitefaciesunit.ThelatertwounitswereformedduringtheCaledoniansubductionbetweentheTongbai-DabiemicroplateandtheNorthChinaplate,theformertwounitsaretheproductsofIndosiniancontinental-continentalsubductionandcollisionbetweentheYangtzeandtheNorthChinaplates.