Geochronology of Dabie UHP Rocks


	The Dabie Shan are bounded by the Tan-Lu fault to the east, the Shang-Ma fault to the west, and the Xiaotian-Mozitiang fault to the north (Figs. 2, 5 in [Hacker, 1998 #970]). They formed as a result of Triassic (~240 Ma) collision between the passive northern margin of the Yangtze (south China) craton with the active southern margin of the Sino-Korean (north China) craton. To the west is the Hong'an area, which shows a regular progression of increasing metamorphic grade from greenschist facies in the south to coesite eclogite in the north (Fig. 2 in [Hacker, 1998 #970]). The Dabie Shan show a less regular progression complicated by the presence of a northern magmatic complex consisting of ortho (granitic or tonalitic)- and para (biotite)-gneisses.
	Dabie-Sulu UHP Belt:
	Largest UHP belt in the world.
	Target of the Chinese Deep Continental Drilling program beginning 1998.
	Occupies Triassic suture between northern Sino-Korean and southern Yangtze cratons.
	Consists of three principal units:
		Northern migmatite high-T terrane (Cenozoic?, P<2GPa)
		Central UHP coesite- and diamond-bearing eclogite belt (Triassic, P=2.6-4 GPa)
		Southern HP Barrovian zone (P=0.5-2.1 GPa).
	Contain abundant coesite and hydrous phases (talc, zoisite/epidote, phengite).
	Contain abundant mantle-derived garnet peridotites.
	Contain the world-record lowest ¹⁸O rocks.