" Soutenance de thèse de Xu-Dong HUANG. | Université d'Orléans

Université d'Orléans

Soutenance de thèse de Xu-Dong HUANG.

28/10/2018 - 14:00 - 28/10/2018 - 18:00

URL: http://www.univ-orleans.fr/actus/soutenances

Nom du contact: Etudes Doctorales

Courriel du contact: etudes.doctorales@univ-orleans.fr

Lieu: Zhu Gongshan Building 205 - Nanjing University - CHINA

Titre : Middle-Late Jurassic Cu-Pb-Zn-bearing and W-bearing granitoids and their skarn mineralization in the Nanling Range, South China: the Tongshanling and Weijia deposits.

Discipline : Sciences de la Terre et de l'Univers

ECOLE DOCTORALE EMSTU

Résumé :

The Middle-Late Jurassic Cu-Pb-Zn-bearing and W-bearing granitoids in the Nanling Range were mainly derived from non-simultaneous partial melting of the mafic amphibolitic rocks in the lower crust and the muscovite-rich metasedimentary rocks in the upper-middle crust, respectively. The fertile sources in the Nanling Range are beneficial to the formation of Cu-Pb-Zn and W deposits during Middle-Late Jurassic. The lower-crust origin of the Cu-Pb-Zn-bearing granodiorites is further demonstrated by the dioritic microgranular enclaves in the Tongshanling granodiorite which are reworked restite enclaves derived from partial melting of the mafic amphibolitic source. The Cu and Zn associated with these intrusions were most probably released from the mafic amphibolitic lower crust by partial melting, whereas, Pb was extracted from the upper crust by ascending granodioritic magmas. The emplacement of these ore-bearing granitoid magmas may have a structural connection with the subsequent polymetallic mineralization in some way. For instance, the exoskarn and sulfide-quartz veins in the Tongshanling Cu-Pb-Zn deposit are evidently controlled by magma emplacement-induced wall-rock deformation. The different mineralization types and ore deposits in the Tongshanling Cu-Mo-Pb-Zn-Ag ore district are genetically linked together in the same skarn system as the productions of evolution and zonation. The Weijia granite was crystallized from a F-rich and water-saturated magma. The key factors controlling the occurrence of unusual magnesian skarn W mineralization during Late Jurassic in the Nanling Range mainly include a W enriched metasedimentary source, a fluorine-rich magma, a strong crystal fractionation, and a fluorine-rich hydrosaline melt.