Spatial distribution, P–T–t paths, and tectonic significance of high-pressure mafic granulites from the Daqingshan–Wulashan Complex in the Khondalite Belt, North China Craton

Paleoproterozoic mafic dyke swarms in central part of the North China craton can be divided into two types: metamorphosed and unmetamorphosed.The unmetamorphosed dykes formed in a short duration of～20Ma from 1780 to 1760Ma and were produced by the latest Paleoproterozoic mafic mgmatism in the North China eraton.They may be subdivided into following three groups:high Mg-Ti and low P,low Mg and high Ti-P,and high Mg and low Ti-P,and individual groups have different geochemical features.A new zircon U-Pb age obtained for the high Mg and low Ti-P marie dykes to the northwest of Fengzhen city is 1769±4Ma, in good agreement with previous data such as ~(40)Ar/~(39)Ar and conventional and SHRIMP zircon and baddeleyite U-Pb ages for the unmetamorphosed dykes.Thee_(Hf)(t)values of the dated zircons at 1770Ma vary from-6.4 to+0.4,with an average of -2.2,and are slightly higher than those of the granitic rocks formed at similar time,indicating that the magmas,with little crustal contamination during their ascent,emplacement and crystallization,were derived from an enriched source from the subcontinental lithospheric mantle induced by subducted sediments.In addition,the enriched mantle source for the high Mg and low Ti-P mafic dykes had thee_(Nd)(t) values of - 5.6 to -2.8(average -4.4)and the initial ~(87)St/~(S6)Sr ratios of 0.7040 to 0.7050(average 0.7046),as shown by the data available from the literature.

Enriched mantle source for Palcoproterozoic high Mg and low Ti-P mafic dykes in central part of the North China craton:constraints from zircon Hf isotopic compositions

Magmatic hydrothermal origin of the Hadamengou-Liubagou Au-Mo deposit, Inner Mongolia, China: Constrains on geology, stable and Re-Os isotopes

Geochemical and isotopic study of metasomatic apatite: Implications for gold mineralization in Xindigou, northern China

The early Statherian (ca. 1800–1750 Ma) Prutivka-Novogol large igneous province of Sarmatia : Geochronology and implication for the Nuna/Columbia supercontinent reconstruction

Geochronology, geochemistry and Sr-Nd-Pb-Hf isotopes of the Paleoproterozoic mafic dykes from the Wulashan area, North China Craton: Petrogenesis and geodynamic implications

Re-Os Dating of Molybdenite from Hadamengou Gold Ore Field in Inner Mongolia and Its Geological Significance

The age, petrogenesis and geodynamic implication of Xiaomiaogou granite porphyry dykes in the northern margin of the North China Craton were investigated using geochronology, geochemistry and Sr–Nd–Pb–Hf isotopic data. LA-MC-ICP-MS zircon U–Pb dating yielded the concordant 206Pb/238U weighted mean age of 350.4 ± 1.4 Ma for the dykes, suggesting they were the productions of the Early Carboniferous magmatism in the northern margin of the North China Craton. The granite porphyries display the pronounced A-type affinities: apart from higher zircon saturation temperature, they are high-K calc-alkaline and metaluminous, with high concentrations of K2O + Na2O varying from 7.93 to 8.55 wt.%, incompatible elements (e.g. Zr, Y, Nb and Ce), REEs and 10 000 Ga/Al ratios but less obvious LREE and HREE fractionation. With the lower initial 87Sr/86Sr ratios (0.7055 to 0.7070), negative values of eNd(t) (−7.1 to −4.9) and eHf(t) (−11.2 to −8.0) and old Nd (1505 to 1681 Ma) and Hf (1861 to 2061 Ma) model ages, all the rocks exhibit the similar geochemical compositions to the melts obtained in experimental studies by dehydration melting of meta-basalts, implying a lower continental crust origin. However, the high Mg# values (47.53 to 53.60) and subcontinental lithospheric mantle-like eNd(t), eHf(t) and Pb isotopic compositions ((206Pb/204Pb)i = 17.296–17.766, (207Pb/204Pb)i = 15.460–15.490 and (208Pb/204Pb)i = 37.097–37.568) indicate the involvement of melts from subcontinental lithospheric mantle. Combined with the special features of mafic microgranular enclaves occurring within the granite porphyries, mixing of the lower crust and subcontinental lithospheric mantle of the North China Craton is proposed for the genesis of granite porphyry dykes in this study. During the hybrid magma ascending, pronounced fractional crystallization and crustal assimilation may have also occurred. Based on geochemical criteria, the Xiaomiaogou granite porphyries can be classified into A1 group. Characterized by the compositional features of anorogenic granites, an intraplate setting is envisaged for the formation of Xiaomiaogou granite porphyry dykes. Such a tectonic environment may be related to the northward drift of the North China Craton during rifting away from East Gondwana. Copyright © 2016 John Wiley & Sons, Ltd.

The Early Carboniferous Xiaomiaogou granite porphyry dykes in the northern margin of the North China Craton: implication for crust–mantle interaction and intraplate magmatism

Village, 38km southwest of Wuchuan County, Inner Mongolia. Its mineralization age is still a quite controversial subject, which directly restricts the understanding of metallogenic mechanism and regularity. In this paper, we present the results of Re-Os isotopic age of molybdenites sampled from auriferous quartz vein within the Houshihua gold deposit in an attempt to constrain the timing of the mineralization, the tectonic setting in which the deposit was formed and also to provide more evidence for multi-stage Au-Mo mineralization in the northern margin of the North China Craton.

Chunjiao Chang

Papers

Geochronology, geochemistry and Sr-Nd-Pb-Hf isotopes of the Paleoproterozoic mafic dykes from the Wulashan area, North China Craton: Petrogenesis and geodynamic implications

Re-Os Dating of Molybdenite from Hadamengou Gold Ore Field in Inner Mongolia and Its Geological Significance

The Early Carboniferous Xiaomiaogou granite porphyry dykes in the northern margin of the North China Craton: implication for crust–mantle interaction and intraplate magmatism

Re‐Os Dating of Molybdenites from Houshihua Gold Deposit in Wuchuan County, Inner Mongolia, and Its Geological Significance