Repeated modification of lithospheric mantle in the eastern North China Craton: Constraints from SHRIMP zircon U-Pb dating of dunite xenoliths in western Shandong

Abstract

Four dunite xenoliths from the Tietonggou intrusion of western Shandong, China, were subjected to SHRIMP zircon U-Pb dating to constrain timing of the North China Craton (NCC) destruction, a topic of much controversy. Cathodoluminescence images revealed that 15 of the 18 zircon grains from the xenoliths display striped absorption. The rest showed oscillatory growth zoniation. All the zircons had variable contents of Th (49-3569 ppm; average, 885 ppm) and U (184-5398 ppm; average, 1277 ppm), and variable Th/U ratios (0.15-2.04). These zircon characteristics indicate a magmatic origin. The zircon age data can be divided into five groups: 131-145, 151-164, 261-280, 434-452, and 500-516 Ma. Group I (131-145 Ma) is consistent with timing of formation of the Tietonggou high-Mg diorites. Group II (151-164 Ma) is similar in age to Middle-Late Jurassic magmatism in the eastern NCC, which included both mantle-derived and intensive crust-derived magmatism. Group III (261-280 Ma) is similar in age to the Emeishan large igneous province, and Group IV (434-452 Ma) is similar in age to Paleozoic high-silica magmatism in the eastern NCC. Group V (500-516 Ma) may correspond to the global Pan-African event. Results indicate repeated modification of lithospheric mantle in the eastern NCC, and suggest that the most intensive modification occurred in the late Mesozoic (131-164 Ma).dunite, SHRIMP zircon dating, lithospheric mantle, multiple modification, North China Craton

Geochemistry, zircon U–Pb analysis, and fluid inclusion 40Ar/39Ar geochronology of the Yingchengzi gold deposit, southern Heilongjiang Province, NE China

“…These zircons show obvious striped absorption in CL images (Fig. ) which are similar to mafic magmatic crystalline zircon (Pei et al ., ; Yang et al ., ; Yu et al ., ). We interpret this to represent the timing of intrusion of the diabase–porphyrite, during the Early Silurian.…”

Prelude to Late Triassic Ni–Cu sulphide mineralization in the eastern Central Asian Orogenic Belt: Geochronological and geochemical constraints from Middle Triassic mafic‐ultramafic magmatism in central and eastern Jilin Province, NE China

“…Liati et al, 2004). Zircons in mafic-ultramafic rocks are widely reported in worldwide, for instance, zircons have existed in garnet peridotite and eclogite in Alps and Spain (Liati & Gebauer, 2002;Sanchez-Rodriguez & Gebauer, 2000), and in southern Australia (Chen et al, 1994;Rudnick et al, 1999) and western Shandong (Yang et al, 2012).…”