Timing of Lithospheric Extension in Northeastern China: Evidence from the Late Mesozoic Nianzishan A-Type Granitoid Complex

2019 ◽  
Vol 30 (4) ◽  
pp. 689-706 ◽  
Author(s):  
Jinhua Qin ◽  
Cui Liu ◽  
Yuchuan Chen ◽  
Jinfu Deng
Keyword(s):  
Northeastern China ◽  
Late Mesozoic ◽  
Lithospheric Extension ◽  
Granitoid Complex

Late-Mesozoic tectonic evolution and magmatic history of the Zhe-Gan-Wan region, SE China: evidence from the Shiling rhyolite and other Yanshanian granitoids

2019 ◽  
Vol 196 (2) ◽  
pp. 89-109
Author(s):  
Xiu Liu ◽  
Xinqi Yu ◽  
Pengju Li ◽  
Jun Hu ◽  
Mengyan Liu ◽  
...  
Keyword(s):  
Late Jurassic ◽  
Southern China ◽  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Distribution Patterns ◽  
Igneous Rocks ◽  
Late Mesozoic ◽  
Plate Movement ◽  
Lithospheric Extension ◽  
Peraluminous Granites

Yanshanian granitoids (178–120 Ma, Jurassic to Cretaceous), which intruded into Precambrian crystalline base- ment and Paleozoic strata, are widely distributed at the junction of the Zhejiang, Jiangxi and Anhui provinces (the ZGW region) in southern China, along with coeval volcanic rocks. This paper summarizes zircon U–Pb age data, geochemi- cal characteristics and Sr-Nd isotopic characteristics of the Late Jurassic to Middle Cretaceous granitoids and volcanic rocks from the ZGW region. We demonstrate that members of the Shiling rhyolite formed during two different periods of magmatic activity at 154.7 ± 2.5 Ma and 139–134 Ma and that igneous rocks from the different periods have distinct geochemical characteristics. Jurassic igneous rocks of the ZGW region have relatively low SiO2and high Al 2O3contents, and show enrichment of large ion lithophile elements (LILEs) and depletion of high field strength elements (HFSEs). They are strongly enriched in LREE and depleted in HREEs with weakly negative Eu anomalies and strongly negative Nb, Ta anomalies. Rb and Y concentrations follow the trends of I-type and S-type granites. By contrast, Cretaceous igneous rocks of this region are characterized by high SiO2and low Al2O3contents with negative Eu anomalies. They have typical wing- shaped rare earth element (REE) distribution patterns and show enrichment of Rb, Th, U, Nb, Ta and depletion of Ba, Sr, P and Ti. They have affinity to A-type peraluminous granites or highly-fractionated felsic rocks. Overall, the igneous rocks evolved from high-Sr low-Yb to low-Sr high-Yb, which might reflect the evolution of the tectonic setting from subduction to lithospheric extension/thinning, i. e., a transition from a continental margin subduction setting during the Late Jurassic to a within-plate extensional setting during the Early Cretaceous, at c. 142 ± 3 Ma. The repeated alternation between lava extrusion and extension and extensional fault kinematics in the late Mesozoic is related to the changes of direction and rate of plate movement of the Izanagi and Pacific plates.

Age Constraints on Late Mesozoic Lithospheric Extension and Origin of Felsic Volcanism in the Songliao Basin, NE China

2015 ◽  
Vol 123 (2) ◽  
pp. 153-175 ◽  
Author(s):  
Shuang-Qing Li ◽  
Yi-Zeng Yang ◽  
Qing-Lu Xie ◽  
Yan Wang ◽  
Fukun Chen
Keyword(s):  
Songliao Basin ◽  
Ne China ◽  
Late Mesozoic ◽  
Lithospheric Extension ◽  
Felsic Volcanism ◽  
Age Constraints

PRECISE AGES FOR LODE GOLD MINERALIZATION IN THE XIAOQINLING GOLD FIELD, SOUTHERN MARGIN OF THE NORTH CHINA CRATON: NEW CONSTRAINTS FROM IN SITU U-Pb DATING OF HYDROTHERMAL MONAZITE AND RUTILE

2020 ◽  
Author(s):  
Junchen Liu ◽  
Yitian Wang ◽  
Jingwen Mao ◽  
Wei Jian ◽  
Shikang Huang ◽  
...  
Keyword(s):  
North China Craton ◽  
North China ◽  
Gold Mineralization ◽  
Late Mesozoic ◽  
The North ◽  
Southern Margin ◽  
Lithospheric Extension ◽  
Gold Producer ◽  
Gold Bearing

Abstract The Xiaoqinling gold field, located along the southern margin of the North China craton, is the second largest gold producer in China, which comprises more than 1,200 auriferous quartz veins with a proven gold reserve of at least 800 tons. Previously, the absolute age of the gold metallogenesis in this area has not been well defined due to the lack of suitable dating minerals. This study presents new in situ laser ablation-inductively coupled plasma-mass spectrometry U-Pb ages of coexisting hydrothermal monazite and rutile for the Fancha gold deposit in this area, which yielded 206Pb/238U ages of 127.5 ± 0.7 Ma (n = 65, mean square of weighted deviates [MSWD] = 1.8) and 129.7 ± 4.3 Ma (n = 37, MSWD = 1.4), respectively. Both ages overlap within analytical uncertainty at the 2σ level of significance, suggesting that both gold-bearing veins were emplaced at ca. 128 Ma. Mineralogical observations indicate that the monazite and rutile precipitated simultaneously with gold from the hydrothermal fluid. Our new data, combined with recently published monazite age, define a more precise gold episode, demonstrating that the gold endowment of the Xiaoqinling area was formed during a relatively brief period at ca. 130 to 127 Ma. We suggest that auriferous fluids were generated as a result of interactions between the enriched mantle and the lower crust, which was driven by westward flat slab subduction of the Paleo-Pacific plate during the late Mesozoic. The peak of lithospheric thinning during the postsubduction may have led to the rapid release of gold from the fertilized mantle. Consequently, the large number of gold-bearing veins in the Xiaoqinling area may ultimately be related to the tectonic evolution and mantle fluid processes that occurred during Early Cretaceous lithospheric extension.

scholarly journals Pyroxenite xenoliths record complex melt impregnation in the deep lithosphere of the northwestern North China Craton

2020 ◽  
Author(s):  
Hong-Kun Dai ◽  
Jian-Ping Zheng ◽  
William L Griffin ◽  
Suzanne Y O’Reilly ◽  
Qing Xiong ◽  
...  
Keyword(s):  
North China Craton ◽  
Lithospheric Mantle ◽  
North China ◽  
Northwestern Part ◽  
Isotopic Ratios ◽  
Late Mesozoic ◽  
Peridotite Xenoliths ◽  
Lithospheric Extension ◽  
Melt Impregnation ◽  
Convex Upward

Abstract Transformation of refractory cratonic mantle into more fertile lithologies is the key to the fate of cratonic lithosphere. This process has been extensively studied in the eastern North China Craton (NCC) while that of its western part is still poorly constrained. A comprehensive study of newly-found pyroxenite xenoliths from the Langshan area, in the northwestern part of this craton is integrated with a regional synthesis of pyroxenite and peridotite xenoliths to constrain the petrogenesis of the pyroxenites and provide an overview of the processes involved in the modification of the deep lithosphere. The Langshan pyroxenites are of two types, high-Mg# [Mg2+/(Mg2++Fe2+)*100 = ∼ 90, atomic ratios] olivine-bearing websterites with high equilibration temperatures (880 ∼ 970 oC), and low-Mg# (70 ∼ 80) plagioclase-bearing websterites with low equilibration temperatures (550 ∼ 835 oC). The high-Mg# pyroxenites show trade-off abundances of olivine and orthopyroxene, highly depleted bulk Sr-Nd (ƐNd = +11.41, 87Sr/86Sr = ∼0.7034) and low clinopyroxene Sr isotopic ratios (mean 87Sr/86Sr = ∼0.703). They are considered to reflect the reaction of mantle peridotites with silica-rich silicate melts derived from the convective mantle. Their depletion in fusible components (e.g., FeO, TiO2 and Na2O) and progressive exhaustion of incompatible elements suggest melt extraction after their formation. The low-Mg# pyroxenites display layered structures, convex-upward rare earth element patterns, moderately enriched bulk Sr-Nd isotopic ratios (ƐNd = -14.20 ∼ -16.74, 87Sr/86Sr = 0.7070 ∼ 0.7078) and variable clinopyroxene Sr-isotope ratios (87Sr/86Sr = 0.706-0.711). They are interpreted to be crustal cumulates from hypersthene-normative melts generated by interaction between the asthenosphere and heterogeneous lithospheric mantle. Combined with studies on regional peridotite xenoliths, it is shown that the thinning and refertilization of the lithospheric mantle was accompanied by crustal rejuvenation and that such processes occurred ubiquitously in the northwestern part of the NCC. A geodynamic model is proposed for the evolution of the deep lithosphere, which includes long-term mass transfer through a mantle wedge into the deep crust from the Paleozoic to the Cenozoic, triggered by subduction of the Paleo-Asian ocean and the Late Mesozoic lithospheric extension of eastern Asia.

scholarly journals Anatomy and Systematics of the Confuciusornithidae (Theropoda: Aves) from the Late Mesozoic of Northeastern China

The Auk ◽  
2000 ◽  
Vol 117 (3) ◽  
pp. 836-839 ◽  
Author(s):  
Storrs L. Olson
Keyword(s):  
Northeastern China ◽  
Late Mesozoic ◽  
Subjective Assessments ◽  
Official Policy ◽  
The Individual

Abstract The following critiques express the opinions of the individual evaluators regarding the strengths, weaknesses, and value of the books they review. As such, the appraisals are subjective assessments and do not necessarily reflect the opinions of the editors or any official policy of the American Ornithologists' Union.

scholarly journals Cordilleran magmatism in Yukon and northern British Columbia: characteristics, temporal variations, and significance for the tectonic evolution of the northern Cordillera

2021 ◽  
Author(s):  
A Zagorevski ◽  
C R van Staal
Keyword(s):  
Building Blocks ◽  
Temporal Variations ◽  
Late Mesozoic ◽  
Magmatic Rocks ◽  
Temporal Relationships ◽  
Continental Arc ◽  
Lithospheric Extension ◽  
Tectonic Framework ◽  
Back Arc

Geochemical and temporal characterization of magmatic rocks is an effective way to test terrane definitions and to evaluate tectonic models. In the northern Cordillera, magmatic episodes are mostly interpreted as products of continental arc and back-arc settings. Re-evaluation of Paleozoic and Late Mesozoic magmatic episodes presented herein highlights fundamental gaps in the understanding of the tectonic framework of the northern Cordillera. In many cases, the character of magmatism and temporal relationships between various magma types do not support existing tectonic models. The present re-evaluation indicates that some of the magmatic episodes are best explained by lithospheric extension rather than arc magmatism. In addition, comparison to modern analogues suggests that many presently defined terranes are not the fundamental tectonic building blocks, but rather combine distinctly different tectonic elements that may not be related each other. Grouping of these distinctly different tectonic elements into single terranes hinders the understanding of Cordilleran evolution and its mineral deposits.

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