Metamorphic P–T–t evolution of mafic HP granulites in the northeastern segment of the Tarim Craton (Dunhuang block): Evidence for early Paleozoic continental subduction

He Z, Zhang Z, Zong K, Xiang H, Klemd R (2014)


Publication Type: Journal article

Publication year: 2014

Journal

Publisher: Elsevier

Book Volume: 169

Pages Range: 1-13

DOI: 10.1016/j.lithos.2014.02.020

Abstract

The Dunhuang block, which constitutes the northeastern segment of the Tarim Craton, is located between the Central Asian Orogenic Belt (CAOB) to the north and the Altyn-Qilian Orogenic Belt to the south. The present study reveals that the early Paleozoic HP mafic granulites from the Dunhuang block underwent four stages of metamorphism: prograde amphibolite-facies (M1), peak high-pressure (HP) granulite-facies (M2) and two late stages of amphibolite-facies retrograde metamorphism. Based on phase equilibrium modeling, P-T conditions of the four stages of metamorphism are estimated at 720-750. °C and 11-13. kbar, 760-800. °C and 14-16. kbar, 690-720. °C and 8-8.5. kbar, and at <. 6. kbar and <. 640. °C respectively. Peak granulite-facies metamorphism is characterized by a low geothermal gradient of ca. 16. °C/km. Zircon U-Pb dating shows that the HP granulite-facies metamorphism occurred at ca. 431. Ma and the early retrograde amphibolite-facies overprint at ca. 403. Ma. Thus the investigated mafic rocks here reveal a clockwise P-T-t path involving burial heating before peak granulite-facies metamorphism and subsequent decompression-cooling with an uplift rate of ca. 0.8. km/Ma. This, together with a continental affinity of the HP metamorphic rocks, indicates that the Dunhuang block experienced a collisional orogenesis during the early Paleozoic. © 2014 Elsevier B.V.

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APA:

He, Z., Zhang, Z., Zong, K., Xiang, H., & Klemd, R. (2014). Metamorphic P–T–t evolution of mafic HP granulites in the northeastern segment of the Tarim Craton (Dunhuang block): Evidence for early Paleozoic continental subduction. Lithos, 169, 1-13. https://dx.doi.org/10.1016/j.lithos.2014.02.020

MLA:

He, Zhenyu, et al. "Metamorphic P–T–t evolution of mafic HP granulites in the northeastern segment of the Tarim Craton (Dunhuang block): Evidence for early Paleozoic continental subduction." Lithos 169 (2014): 1-13.

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