Paleoproterozoic Multiple Tectonothermal Events in the Longshoushan Area, Western North China Craton and Their Geological Implication: Evidence from Geochemistry, Zircon U–Pb Geochronology and Hf Isotopes

Zeng, Renyu; Lai, Jin; Mao, Xiaoming; Li, Bin; Zhang, Jiandong; Bayless, Richard C.; Yang, Lizhi

doi:10.3390/min8090361

Cited by 20 publications

(19 citation statements)

References 101 publications

(110 reference statements)

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“…The Yushigou diabase is characterized by a relatively low ϵ Nd (t) value (−14.4 to −13.4), EM-I-like Pb isotopic compositions, an enrichment in alkali, LREE and LILE contents, and a depletion in HFSE and HREE contents. These results indicate that the rock was derived from an enriched mantle source and/or it underwent extensive crustal contamination during ascent within the continental crust (Li et al 2015;Zeng et al 2018). As mentioned in Section 6.b.1, the Yushigou diabase did not undergo substantial crustal contamination during magmatic evolution.…”

Section: B3 Source Characteristicsmentioning

confidence: 60%

“…The Longshoushan area consists primarily of outcrops of the Mesoarchean-Palaeoproterozoic Longshoushan Complex (Gong et al 2016;Zeng et al 2018), the late Mesoproterozoic Dunzhigou Group (Xu & Jiang, 2003) and the Neoproterozoic-Cambrian Hanmushan Group (Xie et al 2013). As the basement rock, the NWW-striking Longshoushan Complex is exposed in a long narrow belt that is approximately 500 km long and 30 km wide (Tung et al 2007).…”

Section: Geological Setting and Petrologymentioning

confidence: 99%

“…It is in unconformable contact with the overlying strata of the Dunzhigou Group. The Longshoushan Complex underwent strong deformation, low-amphibolite facies regional metamorphism and migmatization during the middlelate Orosirian period (Tung et al 2007;Zeng et al 2018). It mainly consists of marbles, amphibolites, schists, leptynites and migmatites.…”

Section: Geological Setting and Petrologymentioning

confidence: 99%

“…Based on banded zoning or weak oscillatory zoning structures and high Th/U ratios (0.61-1.16; average, 0.88), the zircon grains from the Yushigou diabase can be ascribed to typical magmatic zircons crystallized from mafic rocks. In addition, the diabase dyke intrudes into the early Precambrian metamorphic basement, which is characterized by a large amount of Palaeoproterozoic zircon (Tung et al 2007;Zeng et al 2018). The youngest detrital zircon in the metamorphic For the calculation of ϵ Hf (t) values, we adopted the 176 Lu decay constant of 1.867 × 10 −11 (Söderlund et al 2004), and the present-day chondritic values of 176 Lu/ 177 Hf = 0.0332 and 176 Hf/ 177 Hf = 0.282772 (Blichert-Toft & Albarède, 1997).…”

Section: A Emplacement Agementioning

confidence: 99%

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Geochemistry and zircon ages of the Yushigou diabase in the Longshoushan area, Alxa Block: implications for crust–mantle interaction and tectonic evolution

et al. 2020

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The North Qilian orogenic belt in North China has been defined as a subduction–collision zone between the Alxa Block and the Qilian Block. We present petrography, zircon U–Pb geochronology, major- and trace-element geochemistry, and Sr–Nd–Pb–Hf isotope analysis for the Yushigou diabase from the Longshoushan area, which is located SW of the Alxa Block, aiming to understand its petrogenetic link to subduction processes. The Yushigou diabase belongs to the tholeiite series, and shows enrichment in light rare earth and large-ion lithophile elements, and a depletion in heavy rare earth and high-field-strength elements. Laser ablation – inductively coupled plasma – mass spectrometry U–Pb zircon dating yielded an emplacement age of 414 ± 9 Ma, with an ϵHf(t) value in the range of −10.3 to 1.8. The whole-rock initial 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios of the diabase range over 16.811–17.157, 15.331–15.422 and 37.768–37.895, respectively. The (87Sr/86Sr)i ratios vary between 0.7086 and 0.7106, and ϵNd(t) values vary between −14.4 and −13.4, which are significantly higher than the ϵHf(t) value (Nd–Hf decoupling). An interpretation of the elemental and isotopic data suggests that the Yushigou diabase was derived from partial melting of an enriched mantle I (EM-I) -type lithospheric mantle in the spinel–garnet transitional zone. Based on the geochemical features and previous regional geological data, we propose that the Silurian magmatism was most likely triggered by slab break-off after the closure of the North Qilian Ocean, and ancient continental materials from the subduction slab metasomatized the overlying lithospheric mantle during exhumation.

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Section: B3 Source Characteristicsmentioning

confidence: 60%

Section: Geological Setting and Petrologymentioning

confidence: 99%

Section: Geological Setting and Petrologymentioning

confidence: 99%

Section: A Emplacement Agementioning

confidence: 99%

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Geochemistry and zircon ages of the Yushigou diabase in the Longshoushan area, Alxa Block: implications for crust–mantle interaction and tectonic evolution

et al. 2020

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“…Strong metamorphism and deformation in multiple periods [33] make the strata fragmented and it is difficult to judge the original stratigraphic sequence [34]. It mainly consists of schlieren and homogenic migmatites, marble, biotite-plagioclase gneiss, granulites, quartz schist, amphibolite, and pyroclastic rock [27,35]. The Dunzigou group is the earliest sedimentary overlying strata in the Longshoushan terrane, which is in angular unconformity contact with the lower Longshoushan group.…”

Section: Geological Background Of the Survey Areamentioning

confidence: 99%

Deep Mineral Exploration of the Jinchuan Cu–Ni Sulfide Deposit Based on Aeromagnetic, Gravity, and CSAMT Methods

et al. 2020

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The exploration of deep mineral resources is an important prerequisite for meeting the continuous demand of resources. The geophysical method is one of the most effective means of exploring the deep mineral resources with a large depth and a high resolution. Based on the study of the geological background, petrophysical properties, and aeromagnetic anomaly characteristics of the Jinchuan Cu–Ni sulfide deposit, which is famous throughout the world, this paper uses the widely used gravity, aeromagnetic, and CSAMT (controlled source audio-frequency magnetotellurics) methods with a complementary resolution to reveal the favorable prospecting position. In order to obtain better inversion results, the SL0 norm tight support focusing regularization inversion method is introduced to process the section gravity and aeromagnetic data of the mining area. By combining the results with CSAMT, it is found that the medium-low resistivity, high density, and the high magnetic anomaly areas near the structural belt can nicely correspond with the known ore-bearing rock masses in the mining area. At the same time, according to the geophysical exploration model and geological and physical property data, four favorable ore-forming prospect areas are delineated in the deep part of the known mining area.

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Magma mixing in the genesis of the Qingshanbao granitoids in the Longshoushan area: Implications for the tectonic evolution of the North Qilian orogenic belt, NW China

et al. 2021

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The geochemical differences of magmatic rocks can be influenced by melt source and magmatic processes, including partial melting, fractional crystallization and magma mixing. New whole‐rock geochemical analyses, zircon U–Pb ages and Hf‐isotope data on granitoids from the Qingshanbao complex in the Longshoushan belt highlight a significant Late Ordovician–Early Silurian magmatic episode during the collision between the Alxa and Qilian‐Qaidam blocks, in which magma mixing was a fundamental process. The Qingshanbao complex comprises K‐feldspar granite, granodiorite and diorite emplaced coevally from 442 to 433 Ma. They exhibit peraluminous to metaluminous I‐type features, are enriched in large‐ion lithophile elements (LILEs) and light rare earth elements (LREEs) and depleted in high‐field‐strength elements (HFSEs). Chondrite‐normalized REE patterns are fractionated (LaN/YbN = 10.2–34.9) with weakly negative Eu anomalies (Eu/Eu* = 0.66–0.94). The 176Lu/177Hf zircon two‐stage model ages (TDM2) and the εHf(t) on zircons extracted from the K‐feldspar granite (1613–2,316 Ma, εHf(t) = −14.4 to −3.0) and granodiorite (1640–2015 Ma, εHf(t) = −9.6 to −3.6) suggest they were formed by the mixing of melts produced by the melting of Mesoproterozoic crustal materials, most likely meta‐basic rocks from the Longshoushan Group, and to a lesser extent mantle materials. In contrast, zircons in the diorite yield TDM2 ages ranging from 964 to 1767 Ma and εHf(t) values of −5.5 to 7.1, implying melting of depleted mantle rocks with subordinate participation of lower crust materials. We suggest that the Qingshanbao complex was emplaced when the North Qilian area was in a transitional stage from a compressional to an extensional environment as early as approximately 442 Ma.

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Paleoproterozoic Multiple Tectonothermal Events in the Longshoushan Area, Western North China Craton and Their Geological Implication: Evidence from Geochemistry, Zircon U–Pb Geochronology and Hf Isotopes

Cited by 20 publications

References 101 publications

Geochemistry and zircon ages of the Yushigou diabase in the Longshoushan area, Alxa Block: implications for crust–mantle interaction and tectonic evolution

Geochemistry and zircon ages of the Yushigou diabase in the Longshoushan area, Alxa Block: implications for crust–mantle interaction and tectonic evolution

Deep Mineral Exploration of the Jinchuan Cu–Ni Sulfide Deposit Based on Aeromagnetic, Gravity, and CSAMT Methods

Magma mixing in the genesis of the Qingshanbao granitoids in the Longshoushan area: Implications for the tectonic evolution of the North Qilian orogenic belt, NW China

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