摘要
Geological, geophysical and geochemical evidence for lower crustal delamination in the Qinling-Dabie orogenic belt is presented and a chemical geodynamie model for lower crustal delamination is developed. The synthetic results suggest that eclogite from the Dabie-Sulu ultrahigh pressure metamorphic belt is the most likely candidate as the delaminated material, and that a cumulative 37—82 km thick eclogitic lower crust is required to have been delaminated in order to explain the relative deficits in Eu, Sr, Cr, Ni, Co, V and Ti in the present total crust composition of the Qinling-Dabie orogenic belt. Delamination of the lower crust can well interpret many geological, geophysical and geochemical characteristics of the belt.
Geological, geophysical and geochemical evidence for lower crustal delamination in the Qinling-Dabie oro-genic belt is presented and a chemical geodynamic model for lower crustal delamination is developed. The synthetic results suggest that eclogite from the Dabie-Sulu ultrahigh pressure metamorphic belt is the most likely candidate as the de-laminated material, and that a cumulative 37-82 km thick eclogitic lower crust is required to have been delaminated in order to explain the relative deficits in Eu, Sr, Cr, Ni, Co, V and Ti in the present total crust composition of the Qin-ling-Dabie orogenic belt. Delamination of the lower crust can well interpret many geological, geophysical and geochemical characteristics of the belt.
基金
Project cosupported by the National Nature Science Foundation of China (Grant Nos. 49625305, 49573183, 49794043, 49672144)
the Ministry of Education of China, the Open Laboratory of Constitution.
