The origin of spongy texture in minerals of mantle xenoliths from the Western Qinling, central China

The Qinling–Dabie orogen in central China is one of the major orogenic belts in East Asia. In the eastern Dabie–Sulu region, mafic lamprophyres show the enriched signatures of old sub-continental lithospheric mantle. However, little is known about the mafic igneous rocks and their lithospheric mantle sources in the western Qinling Range. New 40Ar–39Ar age dating, major- and trace-element data, and isotopic analyses of Qinling lamprophyres reveal their differences from the Dabie Sulu lamprophyres. Biotite 40Ar–39Ar dating yielded a plateau age of 219±2 Ma, identical to the ages of rapakivi-textured granitoids in the area. The association of lamprophyre dykes and rapakivi-textured granitoids indicates that the Qinling region was a post-collisional setting at c. 220 Ma. The Qinling lamprophyres are calc-alkaline, and rich in large ion lithophile elements (e.g. Ba, K), but depleted in Nb, Ta and Ti. They show highly fractionated REE patterns with LaN>100 and HREE <10 times chondrite abundances. εNd (219 Ma) values range from −0.5 to −3.3 and initial Sr isotope values from 0.7036 to 0.7058. These features suggest generation of the lamprophyre by partial melting of a metasomatized, garnet peridotite mantle source. The Qinling lamprophyres are distinct from the Dabie–Sulu lamprophyres in emplacement age (c. 135 Ma for Dabie–Sulu) and isotopic composition, suggesting that the nature of the lithospheric mantle and geodynamic evolution of the Qinling region contrasts with that of the Dabie–Sulu region.

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Geochronology and geochemistry of the Dashui adakitic granitoids in the western Qinling Orogen, central China: implications for Triassic tectonic setting

Geological Journal ◽

10.1002/gj.2541 ◽

2014 ◽

Vol 49 (4-5) ◽

pp. 383-401 ◽

Cited By ~ 27

Author(s):

Jin-Sheng Han ◽

Jun-Ming Yao ◽

Yan-Jing Chen

Keyword(s):

Tectonic Setting ◽

Central China ◽

Qinling Orogen ◽

Western Qinling

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Petrogenesis and tectonic implications of Early Cretaceous andesitic–dacitic rocks, western Qinling (Central China): Geochronological and geochemical constraints

Geoscience Frontiers ◽

10.1016/j.gsf.2018.09.013 ◽

2019 ◽

Vol 10 (4) ◽

pp. 1507-1520 ◽

Cited By ~ 1

Author(s):

Feifei Zhang ◽

Peter A. Cawood ◽

Yunpeng Dong ◽

Yuejun Wang

Keyword(s):

Early Cretaceous ◽

Central China ◽

Western Qinling ◽

Tectonic Implications ◽

Geochemical Constraints

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Geology, geochemistry and genesis of the Huachanggou gold deposit, western Qinling Orogen, central China

Geological Journal ◽

10.1002/gj.2557 ◽

2014 ◽

Vol 49 (4-5) ◽

pp. 424-441 ◽

Cited By ~ 24

Author(s):

Zhenju Zhou ◽

Zhenwen Lin ◽

Yan Qin

Keyword(s):

Gold Deposit ◽

Central China ◽

Qinling Orogen ◽

Western Qinling

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Petrogenesis and Geochronology of Tianshui Granites from Western Qinling Orogen, Central China: Implications for Caledonian and Indosinian Orogenies on the Asian Plate

Minerals ◽

10.3390/min10060515 ◽

2020 ◽

Vol 10 (6) ◽

pp. 515

Author(s):

Muhammad Saleem Mughal ◽

Chengjun Zhang ◽

Amjad Hussain ◽

Hafiz Ur Rehman ◽

Dingding Du ◽

...

Keyword(s):

Partial Melting ◽

Saturation Index ◽

Central China ◽

Qinling Orogen ◽

North China Block ◽

Western Qinling ◽

The North ◽

Western Segment ◽

Indosinian Orogeny ◽

North Qinling

The precise timing, petrogenesis, and geodynamic significance of three granitoid bodies (Beidao granite, Caochuanpu granite, Yuanlongzhen granite, and the Roche type rock) of the Tianshui area in the Western Qinling Orogen, central China, are poorly constrained. We performed an integrated study of petrology, geochemistry, and zircon U-Pb dating to constrain their genesis and tectonic implication. Petrographic investigation of the granites shows that the rocks are mainly monzogranites. The Al saturation index (A/CNK versus SiO2) of the granitoid samples indicates meta-aluminous to peraluminous I-type granites. Their magmas were likely generated by the partial melting of igneous protoliths during the syn-collisional tectonic regime. Rare-earth-elements data further support their origin from a magma that was formed by the partial melting of lower continental crust. The Beidao, Caochuanpu, and Yuanlongzhen granites yielded U-Pb zircon weighted mean ages of 417 ± 5 Ma, 216 ± 3 Ma, and 219 ± 3 Ma, respectively. This study shows that the Beidao granite possibly formed in syn- to post-collision tectonic settings due to the subduction of the Proto-Tethys under the North China Block, and can be linked to the generally reported Caledonian orogeny (440–400 Ma) in the western segment of the North Qinling belt, whereas Yuanlongzhen and Caochuanpu granites can be linked to the widely known Indosinian orogeny (255–210 Ma). These granitoids formed due to the subduction of the oceanic lithospheres of the Proto-Tethyan Qinling and Paleo-Tethyan Qinling. The Roche type rock, tourmaline-rich, was possibly formed from the hydrothermal fluids as indicated by the higher concentrations of boron leftover during the late-stages of magmatic crystallization of the granites.

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Typomorphic Characteristics of Pyrites from the Shuangwang Gold Deposit, Shaanxi, China: Index to Deep Ore Exploration

Minerals ◽

10.3390/min9060383 ◽

2019 ◽

Vol 9 (6) ◽

pp. 383

Author(s):

Wang ◽

Liu ◽

Wang ◽

Zeng ◽

Liu ◽

...

Keyword(s):

Gold Deposit ◽

Inductively Coupled Plasma ◽

Gold Mineralization ◽

Trace Element Composition ◽

Central China ◽

Western Qinling ◽

Inductively Coupled ◽

Contour Maps ◽

Plasma Mass Spectrometry ◽

P Type

The large Shuangwang gold deposit (>80 t gold) is located in the Western Qinling Orogen (WQO) of central China. It is an orogenic-type gold deposit hosted in an NW-extending breccia belt in the Devonian Xinghongpu Formation. Gold mineralization of the Shuangwang deposit is featured by hydrothermal breccia ores with strata fragments cemented by hydrothermal minerals dominated by ankerite, quartz, and pyrite with minor amounts of calcite and albite. Pyrite is the major gold-hosting sulfide and the most abundant ore mineral. Crystal habits, thermoelectricity, and trace-element composition of pyrites from the main ore-forming stage of the Shuangwang gold deposit were studied by microbinocular, BHTE-06 thermoelectric coefficient measuring instrument, and high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). Spatial distribution of the above data for pyrites was delineated by contour maps of morphology index, P-type frequency, and primary halo elements (e.g., supraore halo elements Ba and Sb; near-ore halo elements Pb, Zn, and Cu; and subore halo elements Co, Mo, and Bi). Based on the above results, four target areas (areas between prospecting lines 0 and 1, between lines 14 and 18 below orebody KT9; areas between prospecting lines 30 and 34, between lines 44 and 46 below orebody KT8) were put forward for deep gold exploration in the future. These targets are consistent with the depth extrapolation of proven gold orebodies, indicating the practicality of typomorphic characterization of pyrites as vector to deep/concealed gold orebodies. The effectiveness of the pyrite typomorphic parameter for deep gold prediction seems to be chemical composition, crystal habits, and then thermoelectricity.

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