scholarly journals Neoproterozoic S-type granites in the Alxa Block, westernmost North China and tectonic implications: In situ zircon U-Pb-Hf-O isotopic and geochemical constraints

2014 ◽  
Vol 314 (1) ◽  
pp. 110-153 ◽  
Author(s):  
W. Dan ◽  
X.-H. Li ◽  
Q. Wang ◽  
X.-C. Wang ◽  
Y. Liu
Keyword(s):  
North China ◽  
Tectonic Implications ◽  
Geochemical Constraints

Geological and isotopic geochemical constraints on the evolution of the Fuping Complex, North China Craton

2002 ◽  
Vol 117 (1-2) ◽  
pp. 41-56 ◽  
Author(s):  
Shuwen Liu ◽  
Yuanming Pan ◽  
Jianghai Li ◽  
Qiugen Li ◽  
Jian Zhang
Keyword(s):  
North China Craton ◽  
North China ◽  
Geochemical Constraints

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.

Magnetostratigraphic ages of the Cenozoic Weihe and Shanxi Grabens in North China and their tectonic implications

2021 ◽  
pp. 228914
Author(s):  
Xingqiang Chen ◽  
Shuwen Dong ◽  
Wei Shi ◽  
Andrew V. Zuza ◽  
Zhenhong Li ◽  
...  
Keyword(s):  
North China ◽  
Tectonic Implications

Geochemistry of Paleoproterozoic (∼1770Ma) mafic dikes from the Trans-North China Orogen and tectonic implications

2008 ◽  
Vol 33 (1-2) ◽  
pp. 61-77 ◽  
Author(s):  
Yuejun Wang ◽  
Guochun Zhao ◽  
Peter A. Cawood ◽  
Weiming Fan ◽  
Touping Peng ◽  
...  
Keyword(s):  
North China ◽  
Tectonic Implications
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