LA-ICP-MS U-Pb zircon dating for felsic granulite, Huangtuling area, North Dabieshan: Constraints on timing of its protolith and granulite-facies metamorphism, and thermal events in its provenance

Abstract

Information about the protolith of the Huangtuling granulite in North Dabieshan has been unavailable. The complex evolution history of the rock and its host basement must be further discussed. LA-ICP-MS U-Pb dating was conducted on three textural domains in zircon from a high-temperature, high-pressure felsic granulite in the Huangtuling area, North Dabieshan, Central China. The metamorphic growth-derived detrital zircon domain yields a 207 Pb/ 206 Pb age in the range of (2 493± 54) -(2 500 ± 180) Ma. The magmatic genesis-derived detrital zircon domain gives a 207Pb/ 206Pb age ranging from 2 628 Ma to 2 690 Ma, with an oldest 206pb/ 238U age of (2 790±150) Ma. The metamorphic overgrowth or metamorphic recrystallization zircon domain yields a dicsordia with an upper intercept age of (2 044. 7 ± 29. 3) Ma. Compositions of the mineral assemblage, major element geochemistry, and especially the complex interior texture of the zircon suggest that the prololith of the felsic granulite is of sedimentary origin. Results show that the protolith material of the granulite came from a provenance with a complex thermal history, i. e. ∼ 2. 8 Ga magmatism and ∼2. 5 Ga metamorphism, and was deposited in a basin not earlier than 2. 5 Ga. The high-temperature and high-pressure granulite-facies metamorphic age was precisely constrained at (2. 04 ± 0. 03) Ga, which indicates the granulite in Huangtuling area should be a relict of a Paleoproterozoic UHT (ultrahigh temperature) metamorphosed slab.