scholarly journals Mesozoic adakites in the Lingqiu Basin of the central North China Craton: Partial melting of underplated basaltic lower crust

2006 ◽  
Vol 40 (5) ◽  
pp. 447-461 ◽  
Author(s):  
XUAN-CE WANG ◽  
YONG-SHENG LIU ◽  
XIAO-MING LIU
Keyword(s):  
Partial Melting ◽  
North China Craton ◽  
Lower Crust ◽  
North China

In-situ reaction-replacement origin of hornblendites in the Early Cretaceous Laiyuan complex, North China Craton, and implications for its tectono-magmatic evolution

2021 ◽  
Author(s):  
Jia Chang ◽  
Andreas Audétat ◽  
Jian-Wei Li
Keyword(s):  
Partial Melting ◽  
North China Craton ◽  
Lithospheric Mantle ◽  
Lower Crust ◽  
North China ◽  
Ultramafic Rocks ◽  
Magmatic Evolution ◽  
Mafic Magmas ◽  
Felsic Rocks

Abstract Two suites of amphibole-rich mafic‒ultramafic rocks associated with the voluminous intermediate to felsic rocks in the Early Cretaceous Laiyuan intrusive-volcanic complex (North China Craton) are studied here by detailed petrography, mineral- and melt inclusion chemistry, and thermobarometry to demonstrate an in-situ reaction-replacement origin of the hornblendites. Moreover, a large set of compiled and newly obtained geochronological and whole-rock elemental and Sr-Nd isotopic data are used to constrain the tectono-magmatic evolution of the Laiyuan complex. Early mafic‒ultramafic rocks occur mainly as amphibole-rich mafic‒ultramafic intrusions situated at the edge of the Laiyuan complex. These intrusions comprise complex lithologies of olivine-, pyroxene- and phlogopite-bearing hornblendites and various types of gabbroic rocks, which largely formed by in-situ crystallization of hydrous mafic magmas that experienced gravitational settling of early-crystallized olivine and clinopyroxene at low pressures of 0.10‒0.20 GPa (∼4‒8 km crustal depth); the hornblendites formed in cumulate zones by cooling-driven crystallization of 55‒75 vol% hornblende, 10‒20 vol% orthopyroxene and 3‒10 vol% phlogopite at the expense of olivine and clinopyroxene. A later suite of mafic rocks occurs as mafic lamprophyre dikes throughout the Laiyuan complex. These dikes occasionally contain some pure hornblendite xenoliths, which formed by reaction-replacement of clinopyroxene at high pressures of up to 0.97‒1.25 GPa (∼37‒47 km crustal depth). Mass balance calculations suggest that the olivine-, pyroxene- and phlogopite-bearing hornblendites in the early mafic‒ultramafic intrusions formed almost without melt extraction, whereas the pure hornblendites brought up by lamprophyre dikes required extraction of ≥ 20‒30 wt% residual andesitic to dacitic melts. The latter suggests that fractionation of amphibole in the middle to lower crust through the formation of reaction-replacement hornblendites is a viable way to produce adakite-like magmas. New age constraints suggest that the early mafic-ultramafic intrusions formed during ∼132‒138 Ma, which overlaps with the timespan of ∼126‒145 Ma recorded by the much more voluminous intermediate to felsic rocks of the Laiyuan complex. By contrast, the late mafic and intermediate lamprophyre dikes were emplaced during ∼110‒125 Ma. Therefore, the voluminous early magmatism in the Laiyuan complex was likely triggered by the retreat of the flat-subducting Paleo-Pacific slab, whereas the minor later, mafic to intermediate magmas may have formed in response to further slab sinking-induced mantle thermal perturbations. Whole-rock geochemical data suggest that the early mafic magmas formed by partial melting of subduction-related metasomatized lithospheric mantle, and that the early intermediate to felsic magmas with adakite-like signatures formed from mafic magmas through strong amphibole fractionation without plagioclase in the lower crust. The late mafic magmas seem to be derived from a slightly different metasomatized lithospheric mantle by lower degrees of partial melting.

scholarly journals Fluid Inclusions and C-H-O-S-Pb Isotope Systematics of the Changfagou Deposit, Jilin Province, Northeast China

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-21 ◽  
Author(s):  
Bo Peng ◽  
Bile Li ◽  
Jun Chen
Keyword(s):  
Partial Melting ◽  
North China Craton ◽  
Lower Crust ◽  
North China ◽  
Tectonic Setting ◽  
Ore Deposits ◽  
Jilin Province ◽  
Magmatic Fluid ◽  
Northern Margin ◽  
The North

The Changfagou Cu deposit in Jilin province, China, is located in the eastern segment of the northern margin of the North China Craton and lies at the southern end of the Lesser Xing’an Mountains-Zhanggangcailing Mountains. According to the mineral paragenetic association and its various relationships, the hydrothermal mineralization can be divided into 4 metallogenic stages from early to late: stage I is K-feldspar-quartz-magnetite, stage II is quartz-molybdenite, stage III is quartz-chalcopyrite (polymetallic sulfide), and stage IV is carbonate. Stages II and III are the main metallogenic stages. Overall, the metallogenic fluid associated with the Changfagou deposit is characterized as a F-rich CO2-H2O-NaCl hydrothermal system. The hydrogen and oxygen isotopic characteristics suggest the initial ore-forming fluids of the Changfagou deposit evolved from a primitive magmatic fluid and mixed with meteoric water. The sulfur and lead isotopic characteristics show that the metallogenic material was derived from partial melting of the lower crust. Phase separation or immiscibility is the important mechanism in the precipitation of molybdenum, whereas a decrease in temperature is the important mechanism in the precipitation of copper polymetallic sulfides. The above characteristics are similar to those of the porphyry deposits related to continental environments. Compared with the deposits in the Xilamulun metallogenic belt, both have similar metallogenic ages and tectonic positions. In conclusion, the Changfagou deposit formed in an intracontinental extensional environment due to lithospheric thinning. The mineralization was related to magmatism associated with partial melting of the lower crust. The intersection of the Dunhua-Mishan fracture and Kangbao-Chifeng fracture along the northern margin of the North China Craton is a promising location for porphyry ore deposits related to a continental tectonic setting.

U–Pb and Hf-isotope analysis of zircons in mafic xenoliths from Fuxian kimberlites: evolution of the lower crust beneath the North China craton

2004 ◽  
Vol 148 (1) ◽  
pp. 79-103 ◽  
Author(s):  
Jianping Zheng ◽  
W. L. Griffin ◽  
Suzanne Y. O’Reilly ◽  
Fengxiang Lu ◽  
Chunmei Yu ◽  
...  
Keyword(s):  
North China Craton ◽  
Lower Crust ◽  
North China ◽  
Isotope Analysis ◽  
Hf Isotope ◽  
The North

Comparative studies on two phases of Archaean TTG magmas from different blocks of the North China Craton: petrogenesis and constraints on crustal evolution

2020 ◽  
pp. 1-16
Author(s):  
Houxiang Shan ◽  
Mingguo Zhai ◽  
RN Mitchell ◽  
Fu Liu ◽  
Jinghui Guo
Keyword(s):  
North China Craton ◽  
Lower Crust ◽  
North China ◽  
Tectonic Setting ◽  
Source Material ◽  
Crustal Growth ◽  
Garnet Amphibolite ◽  
The North ◽  
Western Block ◽  
Subducting Slab

Abstract Whole-rock major and trace elements and Hf isotopes of magmatic zircons of tonalite–trondhjemite–granodiorite (TTG) rocks with different ages (2.9, 2.7 and 2.5 Ga) from the three blocks (the Eastern Block, Western Block and Trans-North China Orogen) of the North China Craton were compiled to investigate their respective petrogenesis, tectonic setting and implications for crustal growth and evolution. Geochemical features of the 2.5 Ga TTGs of the Eastern Block require melting of predominant rutile-bearing eclogite and subordinate garnet-amphibolite at higher pressure, while the source material of the 2.7 Ga TTGs is garnet-amphibolite or granulite at lower pressure. The 2.5 Ga TTGs have high Mg#, Cr and Ni, negative Nb–Ta anomalies and a juvenile basaltic crustal source, indicating derivation from the melting of a subducting slab. In contrast, features of the 2.7 Ga TTGs suggest generation from melting of thickened lower crust. The 2.5 and 2.7 Ga TTGs in the Trans-North China Orogen were formed at garnet-amphibolite to eclogite facies, and the source material of the 2.5 Ga TTGs in the Western Block is most likely garnet-amphibolite or eclogite. The 2.5 Ga TTGs in the Trans-North China Orogen and Western Block were generated by the melting of a subducting slab, whereas the 2.7 Ga TTGs in the Trans-North China Orogen derived from melting of thickened lower crust. The Hf isotopic data suggest both the 2.5 and 2.7 Ga TTG magmas were involved with contemporary crustal growth and reworking. The two-stage model age (TDM2) histograms show major crustal growth between 2.9 and 2.7 Ga for the whole North China Craton.

Separating multiple episodes of partial melting in polyorogenic crust: An example from the Haiyangsuo complex, northern Sulu belt, eastern China

2019 ◽  
Vol 132 (5-6) ◽  
pp. 1235-1256
Author(s):  
Peng Feng ◽  
Lu Wang ◽  
Michael Brown ◽  
Songjie Wang ◽  
Xiawen Li
Keyword(s):  
Partial Melting ◽  
North China Craton ◽  
North China ◽  
Eastern China ◽  
Magma Ascent ◽  
Magmatic Zircon ◽  
Weighted Mean ◽  
Heavy Rare Earth Element ◽  
Orogenic Collapse ◽  
The North

Abstract The exotic Haiyangsuo complex is structurally part of the Sulu belt but its contact relationship with surrounding Sulu gneisses is unexposed and therefore unknown, making its affinity uncertain. It comprises gneisses with in-source leucosomes that host minor metabasite bodies; both are cut by leucogranite dikes. In this study, we determine the timing and petrogenesis of leucosomes and leucogranites and assess the tectonic affinity of the complex based on data from gneisses and metabasites. Most zircon from gneisses and leucosomes has oscillatory-zoned cores with CL-bright overgrowth rims, but some has CL-dark cores or mantles between cores and rims. CL-dark and bright zircon yield weighted mean ages of ca. 1817–1812 Ma. CL-dark zircon has flat heavy rare earth element (HREE) patterns and crystallization temperatures of 829–875 °C, suggesting metamorphic growth, whereas rims have steep HREE patterns but a similar range of crystallization temperatures, suggesting growth from anatectic melt; εHf (t = 1813 Ma) of –18.3 to –10.8 indicates a North China Craton source. Magmatic zircon from metabasites yields ages of ca. 825 Ma, similar to those of scattered metabasite occurrences in the North China Craton. Paleoproterozoic zircon cores were scavenged during magma ascent. By contrast, zircon cores from the leucogranites yield concordant dates of 776–701 Ma, consistent with protolith ages in the Sulu belt, whereas overgrowth mantles and rims yield weighted mean ages of ca. 220 Ma and 162 Ma, respectively. Both mantles and rims host multiphase solid inclusions, representing former melt, suggesting anatexis and crystallization of zircon first during initial decompression and then during orogenic collapse of the Sulu belt; whole-rock Nd and Sr isotope compositions implicate the Sulu belt gneisses as the source of these melts. Our interpretation of these data is that the Haiyangsuo complex has an early geologic history similar to the Jiaobei terrane from the southeastern part of the North China Craton and was incorporated into the Sulu belt during Triassic collision of the Yangtze and North China Cratons. The two stages of melting relate to Upper Triassic early exhumation and Upper Jurassic late-stage orogenic collapse, during which the leucogranite magma was derived from a source similar to one elsewhere in the Sulu belt such as the subducted Yangtze Craton and not the North China Craton. This shows that during continental collisions, crust from the upper plate may be dragged into the subduction channel, deformed, and subsequently exhumed in association with partial melting of the crust.

Early Cretaceous Xiuyan adakitic granitoids in the Liaodong Peninsula, eastern China: petrogenesis and implications for lithospheric thinning of the North China Craton

2021 ◽  
Vol 58 (1) ◽  
pp. 50-66
Author(s):  
Yang Dong ◽  
Jingdang Liu ◽  
Yanfei Zhang ◽  
Shiyong Dou ◽  
Yanbin Li ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
North China Craton ◽  
Lower Crust ◽  
North China ◽  
Eastern China ◽  
Lithospheric Thinning ◽  
The North ◽  
Magma Sources ◽  
Liaodong Peninsula ◽  
T Values

Mesozoic magmatic rocks are widely distributed in the North China Craton (NCC) and are crucial to understanding the timing, location, and geodynamic mechanisms of lithospheric thinning of the NCC. In this study, we report geochronological, petrogeochemical, and Lu–Hf isotopic data for adakitic granitoids from different parts of Xiuyan pluton in the Liaodong Peninsula, aiming to constrain their magma sources, petrogenesis, and tectonic implications. The adakites are metaluminous to weakly peraluminous and are classified as high-K calc-alkaline I-type granite with Early Cretaceous zircon U–Pb ages of 129–126 Ma. They exhibit adakite-like geochemical characteristics, such as high Sr content and low Yb and Y contents, coupled with high Sr/Y and no pronounced Eu anomalies. They are enriched in Rb, U, and light rare-earth elements and are depleted in Ta, Nb, P, and Ti. The adakites from the eastern part of the pluton have low εHf(t) values (–8.5 to –4.0) with old TDM2 ages (1.57–1.31 Ga), indicating they were derived from the lower crust containing juvenile mantle-derived materials. In contrast, adakites from the northern part of the pluton have lower εHf(t) values (–19.7 to –16.6) with older TDM2 ages (2.21–2.03 Ga), indicating that they were derived mainly from an ancient crust. Our results show that both adakitic magmas were derived from partial melting of delaminated lower crust. Their relatively high MgO and Ni contents and Mg# values indicate that the melts interacted with mantle peridotites. The lower crust delamination beneath the Liaodong Peninsula resulted from paleo-Pacific plate subduction during the Early Cretaceous, which resulted in thinning of Mesozoic crust in the Xiuyan area.

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