Petrogenesis and tectonic implication of the Late Jurassic Kunyushan granitic complex in the Jiaodong Peninsula, eastern China

2021 ◽  
Author(s):  
JiangTao He ◽  
JunJian Li ◽  
Chao Fu ◽  
HongYing Zhou ◽  
XiuZhang Li ◽  
...  
2007 ◽  
Vol 144 (4) ◽  
pp. 619-631 ◽  
Author(s):  
MING-LAN HOU ◽  
YAO-HUI JIANG ◽  
SHAO-YONG JIANG ◽  
HONG-FEI LING ◽  
KUI-DONG ZHAO

Two suites of granitoids, the Late Jurassic (158 ± 3 Ma) Linglong suite and the Early Cretaceous (130–126 Ma) Guojialing suite, crop out in the northwestern Jiaodong Peninsula, eastern China. The Linglong suite is a monzogranite, comprising alkali feldspar, plagioclase, quartz and Fe-rich biotite. The Guojialing suite includes at least five plutonic bodies of both granodiorite and monzo-granite. The rocks are composed of plagioclase, alkali feldspar, quartz, Mg-rich amphibole and Mg-rich biotite. Both the Linglong and Guojialing suites have adakitic affinity. They are enriched in LREE with high La/Yb ratios and show positive Eu anomalies. The rocks are also enriched in LILE and depleted in HFSE with high Sr/Y ratios. The Linglong granite shows very uniform Sr–Nd isotopic compositions with initial 87Sr/86Sr ratios of 0.7119–0.7126 and εNd (T) values of −21.3 to −21.6, which are similar to those of the local Neoarchaean basement. The Guojialing suite has variable initial 87Sr/86Sr ratios (0.7108–0.7120) and εNd (T) values (−10.8 to −17.2), which are distinct both from those of the Neoarchaean basement and from those of the local enriched lithospheric mantle inferred from the coeval mafic dykes in the studied area. Detailed petrological and geochemical data indicate that the Linglong suite was derived by partial melting of Neoarchaean metamorphic lower-crustal rocks at depth of > 50 km with a eclogite residue, whereas the Guojialing suite was formed by the reaction of delaminated eclogitic crust-derived melt with the upwelling asthenospheric mantle. The petrogenesis of these two contrasting adakitic granitoids suggests intensive lower-crustal delamination during Early Cretaceous times, following a crustal thickening process from the late stage of the Early Jurassic to early stage of the Late Jurassic with crustal thickness of < 32 km to > 50 km, respectively.


2020 ◽  
Author(s):  
Yingxin Song ◽  
Dapeng Li ◽  
Ke Geng ◽  
Pengfei Wei ◽  
Lei Shu ◽  
...  

Lithosphere ◽  
2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
YaYun Liang ◽  
Wenhui Guo ◽  
Yao Ma ◽  
Enquan Zhao

Abstract The eastern North China Craton (NCC) has been recognised as undergoing cratonic destruction during the Mesozoic; however, the mechanism of its destruction is still unclear. The main difference between the proposed models is whether the lower continental crust (LCC) underwent thinning. In this study, we conducted comprehensive analyses of Late Mesozoic felsic intrusive rocks, including Late Jurassic granites (166–146 Ma), Early Cretaceous granodiorites (136–123 Ma), and latest Early Cretaceous granites (123–108 Ma) from the Jiaodong Peninsula, located on the southeastern margin of the NCC. These rocks allowed us to investigate variations in the LCC thickness in this region and to further discuss the destruction mechanism of the eastern NCC. Here, temporal variations in crustal thickness can be tracked using whole-rock La/Yb ratios of the felsic intrusive rocks. Our study shows that the continental crust in the eastern NCC thickened during the Late Jurassic (&gt;40 km) due to compression and the westward subduction of the Palaeo-Pacific Ocean lithosphere beneath the NCC since the Early Jurassic. The continental crust further thickened during the Early Cretaceous, caused by the steepening of the subducting slab after ~144 Ma that produced crustal underplating of mantle-derived melts in an extensional setting. However, the continental crust thinned (20–40 km) during the latest Early Cretaceous, caused by the rollback of the subducting slab after ~123 Ma. The geochemical compositions of three stages of felsic intrusions also suggest that the regional tectonic stress that affects the eastern NCC altered from a compressional to an intraplate extensional environment after ~144 Ma. Thus, the Late Mesozoic destruction of the eastern NCC and its accompanying magmatism were controlled by prolonged thermomechanical-chemical erosion due to low-angle subduction, steepening, and rollback of the Palaeo-Pacific Oceanic lithosphere.


2020 ◽  
Vol 55 (8) ◽  
pp. 5903-5913 ◽  
Author(s):  
Junjian Li ◽  
Pengpeng Zhang ◽  
Guohua Li ◽  
Wengang Liu ◽  
Zhelin Zhao ◽  
...  

2017 ◽  
Vol 155 (5) ◽  
pp. 1040-1062 ◽  
Author(s):  
LI-QIANG YANG ◽  
YILDIRIM DILEK ◽  
ZHONG-LIANG WANG ◽  
ROBERTO F. WEINBERG ◽  
YUE LIU

AbstractThe Jurassic Linglong granites, intrusive into the North China Craton (NCC) in eastern China, provide a critical record of the first major episode of lithospheric-scale extension and magmatism in NE China during Mesozoic time. Our U–Pb zircon dating reveals that the Linglong granites were emplaced during 161–158 Ma, shortly after the inception of a shallow subduction of the Palaeo-Pacific plate beneath East Asia during Middle Jurassic time. These granites have high alkali contents (K2O + Na2O = 8–9 wt%), low MgO and Mg no. values and variable Cr–Ni abundances. Their relatively high Ba and Sr concentrations, relatively low heavy rare Earth element (HREE) and strongly fractionated REE patterns characterize them as high Ba–Sr granites. The negative whole-rock εNd(t) values ranging from −22.4 to −10.9 and wide-ranging zircon εHf(t) values of −39.1 to −1.5 suggest that magmas of the Linglong granites were produced by partial melting of a garnet-amphibolite-bearing lower crust of the Jiaobei Terrane and by re-melting of the Triassic ultrahigh-pressure (UHP) metamorphic rocks and alkaline suites of the Sulu Terrane. The occurrence in the granitic rocks of inherited zircons of the Neoarchaean, Palaeoproterozoic, Neoproterozoic, Palaeozoic and Triassic ages suggests that magmas of the Linglong granites interacted with the ancient crust in these terranes during their ascent. Asthenospheric upwelling, induced by the steepening and rapid rollback of the Palaeo-Pacific slab during Late Jurassic time, provided the heat source for the inferred lower crustal melting. Trench migration and thermal weakening of the crust caused extensional deformation and thinning in the eastern part of the NCC.


2019 ◽  
Vol 70 ◽  
pp. 50-70 ◽  
Author(s):  
Liang Zhang ◽  
Li-Qiang Yang ◽  
Roberto F. Weinberg ◽  
David I. Groves ◽  
Zhong-Liang Wang ◽  
...  

2020 ◽  
Vol 57 (12) ◽  
pp. 1428-1446
Author(s):  
Peng Chai ◽  
Hong-rui Zhang ◽  
Zeng-qian Hou ◽  
Zhi-yu Zhang ◽  
Lei-lei Dong

The Damoqujia gold deposit within the Zhaoping Fault Zone on Jiaodong Peninsula in eastern China is hosted primarily by Mesozoic granitoids and contains >60 t of gold, making it an important gold producer. Three mineralization stages are distinguished (early, middle, and late): (K-feldspar)–sericite–quartz–pyrite, quartz – gold – polymetallic sulfides, and quartz–carbonate. Gold deposition occurred mainly in the middle stage. The primary fluid inclusions of three stages are mainly homogenized at temperatures of 236–389, 191–346, and 104–251 °C, with salinities of 2.96–11.33, 1.39–17.28, and 0.53–11.48 wt.% NaCl equivalent, respectively. Fluid inclusion studies indicate that the metallogenic system evolved from CO2-rich mesothermal homogeneous fluids to CO2-poor aqueous fluids due to inputs of meteoric waters. The gold was carried as a bisulfide complex in the ore-forming fluids. Precipitation of gold was caused by a combination of fluid immiscibility and water–rock interaction. Studies of the fluid inclusion characteristics (medium temperature, CO2-rich, and low salinity H2O–CO2–NaCl homogeneous system), hydrogen and oxygen isotopes ([Formula: see text] = –1.0‰ to 7.6‰, δD = –109‰ to –77‰), sulfur values ([Formula: see text] = 4.5‰ to 8.5‰), and regional geological events show that the ore-forming fluids reservoir was likely metamorphic in origin. Based on the immiscibility of fluid inclusion assemblages, the estimated depth and pressure of trapping are 8.3–10.2 km and 83–276 MPa, respectively, corresponding to the depth and pressure of mineralization.


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