Coesite from Mengzhong eclogite at Dhonghai county, northeastern Jiangsu province, China

Abstract

Coesite has been found as an inclusion in garnet from the Mengzhong eclogite in Donghai county, northeastern Jiangsu province, eastern China. The host eclogite occurs closely associated with regionally developed gneiss and was formed under P-T conditions of about 810~ and more than 28 kbar.

Multichronometric Evidence for an In Situ Origin of the Ultrahigh‐Pressure Metamorphic Terrane of Dabieshan, China

“…1a; Xu et al 1987;Okay and Sengö r 1992;Yin and Nie 1993). Coesite and its quartz pseudomorphs are found as inclusions in garnet, omphacite, kyanite, and epidote from eclogites (!200 mm; Wang et al 1989Wang et al , 1992Yang and Smith 1989;Okay and Sengö r 1993;Zhang et al 1995), marbles Liou 1991, 1993;Xu et al 1992), and very rarely in gneisses (Enami and Zhang 1990;Hirajima et al 1990;Wang and Liou 1991;Liou et al 1997). Eclogites commonly occur as small lenses or blocks !20 m in size within serpentinized ultramafics or as thin layers in granitic gneisses or marbles.…”

Linking continental deep subduction with destruction of a cratonic margin: strongly reworked North China SCLM intruded in the Triassic Sulu UHP belt

“…It formed during the northward deep subduction that accompanied the collision of the Yangtze craton with the North China craton in Triassic time (Ames et al 1993;Li et al 1993Li et al , 2000Jahn 1998;Ye et al 2000) and contains abundant coesite-bearing and diamond-bearing eclogites (Okay et al 1989;Hirajima et al 1990;Xu et al 1992) and many ''orogenic'' peridotitic bodies (Yang et al 1993;Zhang et al 2000Zhang et al , 2003Yang and Jahn 2000;Zheng et al 2003bZheng et al , 2005a. The peridotitic bodies have been divided into Type A (Mantle) and Type B (Crustal) peridotites (Carswell 1983;Zhang et al 2000).…”

SHRIMP U–Pb dating, trace elements and the Lu–Hf isotope system of coesite-bearing zircon from amphibolite in the SW Sulu UHP terrane, eastern China

“…In Sulu-Dabie eclogites, index coesite-and diamondbearing UHP mineral assemblages indicate the subduction of crustal materials to mantle depths >120 km (Okay et al, 1989;Wang et al, 1989;Yang and Smith, 1989;Hirajima et al, 1990;Xu et al, 1992Xu et al, , 2003Xu et al, , 2005Xu et al, 1998). Research on the timing of UHP metamorphism has focused mainly on zircon from eclogites (e.g., Zheng et al, 2003).…”