Geochronology and Sr-Nd-Pb-Hf-O isotope geochemistry of Miocene intrusive rocks from Tsushima Islands, Japan: Constraints on petrogenesis and tectonic setting

Lithos ◽  
2021 ◽  
pp. 106280
Author(s):  
Eun Ji Yi ◽  
Sung Hi Choi ◽  
Ji-In Kim ◽  
Jeong-Hyun Lee ◽  
Nak Kyu Kim
Keyword(s):  
Isotope Geochemistry ◽  
Tectonic Setting ◽  
Intrusive Rocks ◽  
O Isotope

Characterizing magnetite reference material for secondary ion mass spectroscopy (SIMS)

2020 ◽  
Author(s):  
Malin Andersson ◽  
Valentin Troll ◽  
Martin Whitehouse ◽  
Frances Deegan ◽  
Karin Högdahl ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Reference Material ◽  
Crystal Orientation ◽  
Plate Tectonics ◽  
Tectonic Setting ◽  
Isotope Ratios ◽  
Orientation Effects ◽  
O Isotope ◽  
Sims Analysis ◽  
Secondary Ion

<p>Sweden is responsible for over 90% of the iron ore production in the European Union, the bulk of which originates from the Kiruna-Malmberget region in northern Sweden, the type locality for Kiruna-type apatite-iron oxide ores. Despite thorough investigations of these long known deposits, their origin is still debated. Currently, two main formation theories are discussed: formation by orthomagmatic processes (Nyström & Henriquez 1994; Troll et al. 2019), versus hydrothermal processes (Hitzman et al. 1992; Smith et al. 2013).</p><p>Secondary ion mass spectrometry (SIMS) analysis allows gathering of more detailed information regarding intra-crystal variations, such as core to rim growth zonations, than bulk analysis do. Measurements of δ<sup>56</sup>Fe and δ<sup>18</sup>O in Kiruna-type magnetites by SIMS would therefore aid in the determination of their main formation process. However, there are conflicting studies regarding crystallographic orientation effects of δ<sup>56</sup>Fe and δ<sup>18</sup>O in magnetite, and while some authors found that the isotope ratios varied depending on how the crystal was oriented (e.g. Huberty et al. 2010), others found no such effects (e.g. Marin-Carbonne et al. 2011). This research project thus aims to further examine any effects of crystal orientation on Fe and O isotope signatures and identify a suitable magnetite reference material for SIMS analysis. To enable comparison between isotope ratios and crystal orientations, the sample orientations will therefore be determined by electron backscatter diffraction (EBSD) prior to SIMS analysis. SIMS analysis require reference material mounted next to the sample for continuous corrections during analysis. Different magnetite samples will now be tested for usage as reference materials. If a homogeneous reference material is found, future studies can utilise it for further investigations of the formation of Kiruna-type magnetite, as well as any other research concerning δ<sup>56</sup>Fe or δ<sup>18</sup>O in magnetite.</p><p>Hitzman, M.W., Oreskes, N., & Einaudi, M.T. (1992). Geological characteristics and tectonic setting of proterozoic iron oxide (Cu-U-Au-REE) deposits. Precambrian Research. Precambrian Metallogeny Related to Plate Tectonics, vol. 58 (1), pp. 241–287. DOI:10.1016/0301-9268(92)90121-4.</p><p>Huberty, J.M., Kita, N.T., Kozdon, R., Heck, P.R., Fournelle, J.H., Spicuzza, M.J., Xu, H., & Valley, J. W. (2010). Crystal orientation effects in 18O for magnetite and hematite by SIMS. Chemical Geology, vol. 276 (3), pp. 269–283. DOI:10.1016/j.chemgeo.2010.06.012.</p><p>Marin-Carbonne, J., Rollion-Bard, C., & Luais, B. (2011). In-situ measurements of iron isotopes by SIMS: MC-ICP-MS intercalibration and application to a magnetite crystal from the Gunflint chert. Chemical Geology, vol. 285 (1), pp. 50–61. DOI:10.1016/j.chemgeo.2011.02.019.</p><p>Nyström, J.O. & Henriquez, F. (1994). Magmatic features of iron ores of the Kiruna type in Chile and Sweden; ore textures and magnetite geochemistry. Economic Geology, vol. 89(4), pp. 820–839. DOI:10.2113/gsecongeo.89.4.820.</p><p>Smith, M.P., Gleeson, S.A., & Yardley, B.W.D. (2013). Hydrothermal fluid evolution and metal transport in the Kiruna District, Sweden: Contrasting metal behaviour in aqueous and aqueous–carbonic brines. Geochimica et Cosmochimica Acta, vol. 102, pp. 89–112. DOI:10.1016/j.gca.2012.10.015.</p><p>Troll, V.R., Weis, F.A., Jonsson, E., Andersson, U.B., Majidi, S.A., Högdahl, K., Harris, C., Millet, M.-A., Chinnasamy, S.S., Kooijman, E., &Nilsson, K.P. (2019). Global Fe–O isotope correlation reveals magmatic origin of Kiruna-type apatite-iron-oxide ores. Nature Communications, vol. 10(1), pp. 1712. DOI:10.1038/s41467-019-09244-4.</p>

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.

scholarly journals Petrogenesis and Tectonic Setting of Early Cretaceous Intrusive Rocks in the Northern Ulanhot Area, Central and Southern Great Xing’an Range, NE China

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1414
Author(s):  
Baoqiang Tai ◽  
Wentian Mi ◽  
Genhou Wang ◽  
Yingjie Li ◽  
Xu Kong
Keyword(s):  
Early Cretaceous ◽  
Tectonic Setting ◽  
Granite Porphyry ◽  
Granitic Rocks ◽  
Magma Source ◽  
Isotopic Data ◽  
Quartz Porphyry ◽  
Intrusive Rocks ◽  
Quartz Monzonite ◽  
Great Xing’An Range

Abundant Early Cretaceous magmatism is conserved in the central and southern Great Xing’an Range (GXR) and has significant geodynamic implications for the study of the Late Mesozoic tectonic framework of northeast China. In this study, we provide new high-precision U–Pb zircon geochronology, whole-rock geochemistry, and zircon Hf isotopic data for representative intrusive rocks from the northern part of the Ulanhot area to illustrate the petrogenesis types and magma source of these rocks and evaluate the tectonic setting of the central-southern GXR. Laser ablation inductively coupled plasma–mass spectrometry (LA-ICP-MS) zircon U–Pb dating showed that magmatism in the Ulanhot area (monzonite porphyry: 128.07 ± 0.62 Ma, quartz monzonite porphyry: 127.47 ± 0.36, quartz porphyry: 124.85 ± 0.34, and granite porphyry: 124.15 ± 0.31 Ma) occurred during the Early Cretaceous. Geochemically, monzonite porphyry belongs to the metaluminous and alkaline series rocks and is characterized by high Al2O3 (average 17.74 wt.%) and TiO2 (average 0.88 wt.%) and low Ni (average 4.63 ppm), Cr (average 6.69 ppm), Mg# (average 31.11), Y (average 15.16 ppm), and Yb (average 1.62 ppm) content with enrichment in Ba, K, Pb, Sr, Zr, and Hf and depletion in Ti, Nb, and Ta. The granitic rocks (e.g., quartz monzonite porphyry, quartz porphyry, and granite porphyry) pertain to the category of high-K calc-alkaline rocks and are characterized by high SiO2 content (>66 wt.%) and low MgO (average 0.69 wt.%), Mg# (average 31.49 ppm), Ni (average 2.78 ppm), and Cr (average 8.10 ppm) content, showing an affinity to I-type granite accompanied by Nb, Ta, P, and Ti depletion and negative Eu anomalies (δEu = 0.57–0.96; average 0.82). The Hf isotopic data suggest that these rocks were the product of the partial melting of juvenile crustal rocks. Notably, fractionation crystallization plays a crucial role in the process of magma emplacement. Combining our study with published ones, we proposed that the Early Cretaceous intrusive rocks in the Ulanhot area were formed in an extensional tectonic background and compactly related to the subduction of the Paleo-Pacific Ocean plate.

Re-Os dating and H-O isotope geochemistry of the Shimensi deposit, northern Jiangxi, China: Implication for ore genesis

2016 ◽  
Vol 50 (2) ◽  
pp. 139-152 ◽  
Author(s):  
Zhang-Huang Ye ◽  
Peng Wang ◽  
Xin-Kui Xiang ◽  
An-Jian Wang ◽  
Qiang Yan ◽  
...  
Keyword(s):  
Isotope Geochemistry ◽  
Ore Genesis ◽  
O Isotope

Geochronology, geochemistry, and geological implications of late Carboniferous – early Permian mafic and felsic intrusive rocks from Urad Zhongqi, western Inner Mongolia

2015 ◽  
Vol 152 (6) ◽  
pp. 1057-1072 ◽  
Author(s):  
YINGDE WANG ◽  
FENGYUE SUN ◽  
LIANG LI ◽  
RUIHUA LI ◽  
JIAN WANG ◽  
...  
Keyword(s):  
Partial Melting ◽  
Inner Mongolia ◽  
Tectonic Setting ◽  
Field Investigation ◽  
Late Carboniferous ◽  
Transitional Period ◽  
Crustal Material ◽  
Early Permian ◽  
Porphyritic Granite ◽  
Intrusive Rocks

AbstractThe mafic and felsic Haertaolegai intrusions crop out in Urad Zhongqi, western Inner Mongolia and are dominated by monzogranite, porphyritic granite, and gabbroic diorite intrusions. We investigate the tectonic setting, geochronology, and anorogenic characteristics of the western Inner Mongolia through field investigation, microscopic and geochemical analyses of samples from the Haertaolegai bimodal intrusions and laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) zircon U–Pb dating of gabbroic diorite and adakitic granites. Petrographic and geochemical studies of the bimodal intrusions indicate that the gabbroic diorites formed from a primary magma generated by the partial melting of lithospheric mantle material that had previously been modified by subduction-related fluids. The felsic rocks are high-K calc-alkaline and metaluminous, have characteristics of adakitic rocks and were generated during the partial melting of juvenile crustal material. Zircon U–Pb dating indicates that the felsic portion of this pluton was emplaced during late Carboniferous – early Permian time, with the mafic portion of the pluton emplaced during early Permian time. The zircons of adamellites have ɛHf(t) values and TDM2 ages of +1.0 to +2.7 and 1032–1128 Ma, respectively, suggesting that they formed from magmas generated by partial melting of juvenile Mesoproterozoic lower crust. These data, combined with the geology of the region, indicate that the late Carboniferous – early Permian bimodal intrusive rocks in western Inner Mongolia record a transitional period from collisional compression to post-collisional extension. These results indicate that the Paleo-Asian Ocean in western Inner Mongolia closed before 300 Ma.

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