Geochronological and geochemical studies of the OIB-type Baiyanghe dolerites: implications for the existence of a mantle plume in northern West Junggar (NW China)

2018 ◽  
Vol 156 (4) ◽  
pp. 702-724 ◽  
Author(s):  
XIU-QUAN MIAO ◽  
XIN ZHANG ◽  
HUI ZHANG ◽  
JIN-RONG WANG ◽  
ZHENG LIU ◽  
...  
Keyword(s):  
Mantle Plume ◽  
Isotope Geochemistry ◽  
Tectonic Setting ◽  
Major And Trace Elements ◽  
Nd Isotope ◽  
Nw China ◽  
Tholeiite Basalt ◽  
West Junggar ◽  
Geochemical Studies ◽  
T Values

AbstractIn this paper, zircon U–Pb geochronology, major and trace elements, and Sr–Nd isotope geochemistry of the Baiyanghe dolerites in northern West Junggar of NW China are presented. The U–Pb dating of zircons from the dolerites yielded ages of 272.2±4 Ma and 276.7±6.2 Ma, which indicate the emplacement times. The dolerites are characterized by minor variations in SiO2(46.89 to 49.07 wt%), high contents of Al2O3(13.60 to 13.92 wt%) and total Fe2O3(11.14 to 11.70 wt%), and low contents of MgO (2.67 to 3.64 wt%) and total alkalis (Na2O+K2O, 5.1 to 5.97 wt%, K2O/Na2O = 0.37–0.94), which indicate affinities to metaluminous tholeiite basalt. The REE pattern ((La/Sm)N= 2.25–2.34, (La/Yb)N= 7.42–8.36), V–Ti/1000 and 50*Zr–Ti/50–Sm discrimination diagrams show that these rocks are OIB-type. The high contents of Zr and Ti indicate a within-plate tectonic setting, and samples plot in the ‘plume source’ field shown on the Dy/Yb(N)versus Ce/Yb(N)diagram. The positive εNd(t) values (+7.09 to +7.48), high initial87Sr/86Sr ratios (0.70442 to 0.70682) and depletions of Nb and Ta elements in the samples can be explained by the involvement of subducted sediments. In summary, it is possible that the Baiyanghe dolerites were derived from an OIB-like mantle source and associated with a mantle plume tectonic setting. Therefore, our samples provide the youngest evidence for the existence of a mantle plume, which may provide new insights into the Late Palaeozoic tectonic setting of West Junggar.

Gabbro in Wanning, Hainan Island: LA-ICP-MS Chronometry and its Geological Significance

2011 ◽  
Vol 137 ◽  
pp. 307-311
Author(s):  
Li Mei Tang
Keyword(s):  
Tectonic Setting ◽  
Research Work ◽  
Hainan Island ◽  
Major And Trace Elements ◽  
Ocean Basin ◽  
Age Dating ◽  
Icp Ms ◽  
Tethys Ocean ◽  
T Values ◽  
Made In

Gabbro is mostly the result of partly melting from mantle rock, and its formation is usually related with extension tectonic, the research work on Triassic gabbro from Hainan island has important instruction significance to its tectonic background. System chronometry and geochemistry research on hornblende gabbro in Wanning area was made in this paper, and its tectonic significance is to be discussed. The LA-ICP-MS zircon U-Pb age dating result shows that the gabbro in Wanning area was formed in 241±1.7Ma. The major and trace elements characteristic shows that the rocks belong to alkaline series, enrichment in light REE (LREE/HREE＝7.22-8.5) and LILE Rb, Th, and Sr, Ba while depleted in HFSE Nb, Ta and Zr, Hf. The Wanning gabbro exhibits a narrow range of εNd(t) values (1.59-1.76), and a broad rang 87Sr/86Sr initial ratios(0.70633-0.70964). The tectonic background of Wanning gabbro is intracontinental extensional setting, and its geochemistry characteristic declare that there was an ancient ocean basin existed, and maybe one branch of the ancient eastern Tethys ocean. The formation age and tectonic setting declare that the ancient ocean basin was disappeared at least before 241Ma.

scholarly journals Supplemental Material: Picrite-basalt complex in the Baoshan-Gongshan Block of northern Sibumasu: Onset of a mantle plume before breakup of Gondwana and opening of the Neo-Tethys Ocean

2021 ◽  
Author(s):  
Li Su ◽  
et al.
Keyword(s):  
Trace Elements ◽  
Mantle Plume ◽  
Potential Temperature ◽  
Major And Trace Elements ◽  
Nd Isotope ◽  
Tethys Ocean ◽  
Mantle Potential Temperature

Table S1-1: Olivine compositions of Menglian picrites; Table S1-2: Clinopyroxene compositions of Menglian picrites; Table S1-3: Spinel compositions of Menglian picrites; Table S2: Major and trace elements of picrites-basalts in the Baoshan-Gongshan block; Table S3: Whole-rock Rb–Sr and Sm–Nd isotope compositions of picrites and basalts from Baoshan-Gongshan Block; Table S4-1: Zircon U-Pb analyses of gabbroic samples of the picrite-basalt complex in Baosan-Gongshan Block; Table S4-2: Zircon U-Pb analyses of diabase sample (ST-23) of the picrite-basalt complex in Baosan-Gongshan Block; Table S4-3: U-Pb analyses of zircon Standards; Table S5: Calculated mantle potential temperature (Tp) and pressure for picrites and basalts in the Baoshan-Gongshan block.

Petrogenesis and tectonic setting of the Tuyeh-Darvar Granitoid (Northern Iran): Constraints from zircon U-Pb geochronology and Sr-Nd isotope geochemistry

Lithos ◽  
2018 ◽  
Vol 318-319 ◽  
pp. 494-508 ◽  
Author(s):  
Azin Naderi ◽  
Habibollah Ghasemi ◽  
José F. Santos ◽  
Fernando Rocha ◽  
William L. Griffin ◽  
...  
Keyword(s):  
Isotope Geochemistry ◽  
Tectonic Setting ◽  
Northern Iran ◽  
Nd Isotope

scholarly journals Sm–Nd isotope geochemistry and tectonic setting of the metasedimentary rocks from the basal allochthonous units of NW Iberia (Variscan suture, Galicia)

Lithos ◽  
2012 ◽  
Vol 148 ◽  
pp. 196-208 ◽  
Author(s):  
José Manuel Fuenlabrada ◽  
Ricardo Arenas ◽  
Rubén Díez Fernández ◽  
Sonia Sánchez Martínez ◽  
Jacobo Abati ◽  
...  
Keyword(s):  
Isotope Geochemistry ◽  
Tectonic Setting ◽  
Nd Isotope ◽  
Metasedimentary Rocks ◽  
Nw Iberia

scholarly journals Supplemental Material: Picrite-basalt complex in the Baoshan-Gongshan Block of northern Sibumasu: Onset of a mantle plume before breakup of Gondwana and opening of the Neo-Tethys Ocean

2021 ◽  
Author(s):  
Li Su ◽  
et al.
Keyword(s):  
Trace Elements ◽  
Mantle Plume ◽  
Potential Temperature ◽  
Major And Trace Elements ◽  
Nd Isotope ◽  
Tethys Ocean ◽  
Mantle Potential Temperature

Table S1-1: Olivine compositions of Menglian picrites; Table S1-2: Clinopyroxene compositions of Menglian picrites; Table S1-3: Spinel compositions of Menglian picrites; Table S2: Major and trace elements of picrites-basalts in the Baoshan-Gongshan block; Table S3: Whole-rock Rb–Sr and Sm–Nd isotope compositions of picrites and basalts from Baoshan-Gongshan Block; Table S4-1: Zircon U-Pb analyses of gabbroic samples of the picrite-basalt complex in Baosan-Gongshan Block; Table S4-2: Zircon U-Pb analyses of diabase sample (ST-23) of the picrite-basalt complex in Baosan-Gongshan Block; Table S4-3: U-Pb analyses of zircon Standards; Table S5: Calculated mantle potential temperature (Tp) and pressure for picrites and basalts in the Baoshan-Gongshan block.

scholarly journals Petrogenesis of Low Sr and High Yb A-Type Granitoids in the Xianghualing Sn Polymetallic Deposit, South China: Constrains from Geochronology and Sr–Nd–Pb–Hf Isotopes

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 182 ◽  
Author(s):  
ChangHao Xiao ◽  
YuKe Shen ◽  
ChangShan Wei
Keyword(s):  
South China ◽  
Tectonic Setting ◽  
Major And Trace Elements ◽  
Al2o3 Content ◽  
Hf Isotopes ◽  
Geodynamic Setting ◽  
Crustal Model ◽  
Extensional Tectonic ◽  
Polymetallic Mineralization ◽  
T Values

The nature and origin of the early Yanshanian granitoids, widespread in the South China Block, shed light on their geodynamic setting; however, understanding their magmatism processes remains a challenge. In this paper, we present both major and trace elements of bulk rock, Sr–Nd–Pb isotopic geochemistry, and zircon U–Pb–Hf isotopes of the low Sr and high Yb A2-type granites, which were investigated with the aim to further constrain their petrogenesis and tectonic implications. Zircon U–Pb dating indicates that these granites were emplaced at ca. 153 Ma. The granites are characterized by high SiO2 (>74 wt.%) and low Al2O3 content (11.0 wt.%–12.7 wt.%; <13.9 wt.%). They are enriched in large ion lithophile elements (LILEs) (e.g., Rb, Th, U, and K) and Yb, but depleted in high field-strength elements (HFSEs) (e.g., Nb, Ta, Zr and Hf), Sr, Ba P, Ti and Eu concentrations. They exhibit enriched rare earth elements (REEs) with pronounced negative Eu anomalies. They have εNd(t) values in a range from −6.5 to −9.3, and a corresponding TDM model age of 1.5 to 1.7 Ga. They have a (206Pb/204Pb)t value ranging from 18.523 to 18.654, a (207Pb/204Pb)t value varying from 15.762 to 15.797, and a (208Pb/204Pb)t value ranging from 39.101 to 39.272. The yield εHf(t) ranges from −6.1 to −2.1, with crustal model ages (TDMC) of 1.3 to 1.6 Ga. These features indicate that the low Sr and high Yb weakly peraluminous A2-type granites were generated by overlying partial melting caused by the upwelling of the asthenosphere in an extensional tectonic setting. The rollback of the Paleo-Pacific Plate is the most plausible combined mechanism for the petrogenesis of A2-type granites, which contributed to the Sn–W polymetallic mineralization along the Shi-Hang zone in South China.

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