Premium
Lithospheric mapping: a pathfinder for hidden terrane and ore systems in southren Lhasa block
Author(s) -
Xu Bo,
Griffin William L.,
Hou ZengQian,
O'Reilly Suzanne Y.,
Xiong Qing,
Guo Zhen,
Pearson Norman J.,
Greau Yoann,
Yang ZhiMing,
Zheng YuanChuan
Publication year - 2019
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/1755-6724.14041
Subject(s) - pathfinder , terrane , lithosphere , block (permutation group theory) , geology , seismology , tectonics , computer science , geometry , library science , mathematics
Widespread Miocene (24-8Ma) mantle-derived ultrapotassic rocks, lamprophyres and their entrained xenoliths, provide information on the composition, geometry and thermal state of the sub-continental lithospheric mantle in southern Tibet during the India-Asia continental collision. The geochemical and isotopic characteristics of the ultrapotassic rocks along the Lhasa block delineate two distinct lithospheric source domains that have different histories of depletion and enrichment. The eastern ultrapotassic rocks (89-92°E) reveal a depleted, young and fertile lithospheric mantle (Sr/Srt=0.704 to 0.707; εHf(t) = +7.7 to +0.5; Hf TDM =216-499 Ma). The western ultrapotassic rocks (79-89°E) and peridotite xenoliths (81°E) reflect a refractory harzburgitic mantle refertilized by ancient metasomatism (the lavas have: Sr/Srt=0.714-0.734, εHf(t)= +1.1 to -21.2, Hf TDM = 1001-2471 Ma; the peridotites have Sr/Srt= 0.709-0.716).