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.

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 Geochronology and Geochemistry of Ore-Hosting Rhyolitic Tuff in the Kengdenongshe Polymetallic Deposit in the Eastern Segment of the East Kunlun Orogen

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 589 ◽  
Author(s):  
Liang ◽  
Xia ◽  
Shan ◽  
Ma ◽  
Zhao ◽  
...  
Keyword(s):  
Large Scale ◽  
Major And Trace Elements ◽  
Polymetallic Deposit ◽  
East Kunlun ◽  
Low Concentrations ◽  
Icp Ms ◽  
Eastern Segment ◽  
Rhyolitic Tuff ◽  
Tethys Ocean ◽  
Bayan Har

The Kengdenongshe Au–Ag–Pb–Zn polymetallic deposit, a newly discovered large-scale polymetallic deposit in the southeastern section of the East Kunlun Orogen (EKO), contains an Au resource of 40 t, Ag resource of 690 t and Pb–Zn resource of 10.5 × 105 t. The ore-bearing rocks are mainly composed of laminar barite and rhyolitic tuff. In this study, LA-ICP-MS zircon U–Pb dating and whole rock major and trace elements analyses have been conducted on the ore-bearing rhyolitic tuff. LA-ICP-MS zircon U–Pb dating data show that these rhyolitic tuffs were emplaced at ca. 243.3 ± 1.6 Ma. The samples show similar features to those of S-type granites, including high contents of SiO2 (76.4–82.6 wt. %) and Al2O3 (11.0–12.7 wt. %) and relatively low concentrations of Na2O (0.35–2.43 wt. %) and CaO (0.095–0.124 wt. %), with high A/CNK (molar [Al2O3/(CaO + Na2O + K2O)]) (1.72–2.03) and K2O/Na2O ratios (1.41–17.1). Further, they exhibit depletion in HFSEs (High Field Strength Elements) and enrichment in LREEs (Light Rare Earth Element) with negative Eu anomalies (Eu/Eu* = 0.51–0.64). These geochemical characteristics indicate that the Kengdenongcuo rhyolitic tuff originated from the fluid-absent melting of a plagioclase-poor, clay-rich metapelitic source and experienced minor fractional crystallization. In combination with arc-type magmatism and contemporaneous syn-collision granitoids in the region, the Kengdenongcuo tuff formed in a continental collision setting, implying that the Bayan Har–Songpan Ganzi Terrane collided with the East Kunlun Terrane and the Paleo-Tethys Ocean was closed at the period of ~243 Ma. The Kengdenongcuo polymetallic deposit formed at about the same time.

scholarly journals Supplemental Material: Multiple sources and magmatic evolution of the Late Triassic Daocheng batholith in the Yidun Terrane: Implications for evolution of the Paleo-Tethys Ocean in the eastern Tibetan Plateau

2021 ◽  
Author(s):  
Pengsheng Dong ◽  
Guochen Dong
Keyword(s):  
Trace Elements ◽  
Geochemical Modeling ◽  
Major And Trace Elements ◽  
Late Triassic ◽  
Magmatic Evolution ◽  
Eastern Tibetan Plateau ◽  
Isotopic Data ◽  
Multiple Sources ◽  
Icp Ms ◽  
Tethys Ocean

Table S1: Mineral association of samples from the Daocheng batholith; Table S2: LA-ICP-MS U-Pb isotopic data for zircons from the Daocheng batholith; Table S3: Hf isotopic data for zircons from the Daocheng batholith; Table S4: Trace elements data for zircons from the Daocheng batholith; Table S5: Major and trace elements data for the Daocheng batholith; Table S6: Whole-rock Sr-Nd isotopic data of the Daocheng batholith; Table S7: Representative microprobe analyses of amphibole from the Daocheng batholith; Table S8: Partition coefficient for minerals used in geochemical modeling.

scholarly journals Supplemental Material: Multiple sources and magmatic evolution of the Late Triassic Daocheng batholith in the Yidun Terrane: Implications for evolution of the Paleo-Tethys Ocean in the eastern Tibetan Plateau

2021 ◽  
Author(s):  
Pengsheng Dong ◽  
Guochen Dong
Keyword(s):  
Trace Elements ◽  
Geochemical Modeling ◽  
Major And Trace Elements ◽  
Late Triassic ◽  
Magmatic Evolution ◽  
Eastern Tibetan Plateau ◽  
Isotopic Data ◽  
Multiple Sources ◽  
Icp Ms ◽  
Tethys Ocean

Table S1: Mineral association of samples from the Daocheng batholith; Table S2: LA-ICP-MS U-Pb isotopic data for zircons from the Daocheng batholith; Table S3: Hf isotopic data for zircons from the Daocheng batholith; Table S4: Trace elements data for zircons from the Daocheng batholith; Table S5: Major and trace elements data for the Daocheng batholith; Table S6: Whole-rock Sr-Nd isotopic data of the Daocheng batholith; Table S7: Representative microprobe analyses of amphibole from the Daocheng batholith; Table S8: Partition coefficient for minerals used in geochemical modeling.

scholarly journals Copper Mineralization Potential of Late Triassic Granitoids in Northern Yidun Arc, SW China

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 337 ◽  
Author(s):  
Xing-Yuan Li ◽  
Jing-Ru Zhang ◽  
Hao Song ◽  
Chun-Kit Lai
Keyword(s):  
Age Dating ◽  
Late Triassic ◽  
Clear Correlation ◽  
Sw China ◽  
Copper Mineralization ◽  
Icp Ms ◽  
High Concentrations ◽  
T Values ◽  
Yidun Arc

Yidun arc is an important constituent of the Sanjiang Tethyan Domain in SW China. The Changdagou pluton, located in the northern part of the Yidun Arc, mainly consists of granodiorite. In this study, we conducted in-situ LA-ICP-MS zircon U-Pb dating, and trace element and Hf isotope analyses on the Changdagou granites. Age dating results yielded a weighted mean U-Pb age of 214.97 ± 0.98 Ma (MSWD = 1.2, 2σ), broadly coeval with extensive late Triassic magmatism across the Yidun Arc. All zircon grains analyzed showed high concentrations of Th, U, and HREE, with positive Ce and negative Eu anomalies. Logfo2 and CeN/CeN* values vary from FMQ −3.14 to FMQ +7.44 (average FMQ +3.98), and 14 to 172 (avg. 98), respectively. The zircon EuN/EuN* (avg. 0.22) ratios have no clear correlation with the CeN/CeN* ratios, suggesting that the former were mainly affected by the magma water content. In addition, zircon εHf(t) values vary in a narrow range (–2.9 to −4.9, avg. −3.4) that clusters around zero, indicating a greater component of mantle-derived magma. Hence, we propose that the Changdagou granodiorite was derived from a highly oxidized, “wet”, Cu-rich source, of the type likely to generate porphyry Cu mineralization. However, these parameters (logfO2, EuN/EuN*, (Ce/Nd)/Y, and εHf(t)) are all lower than those of intrusions associated with Cu ores at Pulang and Lannitang, which may explain why the Cu deposit discovered at Changdagou is small by comparison. Furthermore, on the basis of the decreasing trends of εHf, logfO2, and H2O content from south to north along the Yiduan arc, we infer that the northern segment of the Yidun arc (including Changdagou) was located further away from the subduction front.

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.

Age and tectonic setting of the East Taiwan Ophiolite: implications for the growth and development of the South China Sea

2016 ◽  
Vol 154 (3) ◽  
pp. 441-455 ◽  
Author(s):  
ROBERT B.-J. HSIEH ◽  
J. GREGORY SHELLNUTT ◽  
MENG-WAN YEH
Keyword(s):  
South China Sea ◽  
South China ◽  
Tectonic Setting ◽  
The South China Sea ◽  
Spreading Ridge ◽  
The South ◽  
China Sea ◽  
Marginal Seas ◽  
Icp Ms ◽  
T Values

AbstractThe South China Sea is one of the youngest marginal seas and understanding its development is important for reconstructing the tectonic evolution of Southeast Asia. The South China Sea is thought to have been actively spreading between 32 Ma and 15.5 Ma. The East Taiwan Ophiolite (ETO) is one of the few preserved remnants of the South China Sea on land and provides an opportunity to investigate the age and the tectonic setting of the accreted easternmost portion. The age of the ETO was obtained by LA-ICP-MSin situzircon U–Pb methods and yielded a mean206Pb–238U age of 14.1±0.4 Ma, suggesting that magmatic activity in the South China Sea continued ~1.5 million years beyond current estimates. Cr-spinel data (Cr no. = 42–54) and depleted εNd(t) values (i.e. +9.1 to +11.4) from the serpentinized peridotites and gabbros and the light rare earth element depleted patterns (La/Yb ≤ 1) of the ETO mafic rocks are consistent with a ridge setting (i.e. N-MORB composition). Therefore, the ETO likely represents the terminal portion of the South China Sea spreading ridge that was sheared off during the northward translation of the Luzon arc.

scholarly journals Two stages of Late Carboniferous to Triassic magmatism in the Strandja Zone of Bulgaria and Turkey

2021 ◽  
pp. 1-14
Author(s):  
Anna Sałacińska ◽  
Ianko Gerdjikov ◽  
Ashley Gumsley ◽  
Krzysztof Szopa ◽  
David Chew ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Tectonic Setting ◽  
Age Groups ◽  
Late Carboniferous ◽  
The Balkans ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
Tethys Ocean ◽  
Two Stages

Abstract Although Variscan terranes have been documented from the Balkans to the Caucasus, the southeastern portion of the Variscan Belt is not well understood. The Strandja Zone along the border between Bulgaria and Turkey encompasses one such terrane linking the Balkanides and the Pontides. However, the evolution of this terrane, and the Late Carboniferous to Triassic granitoids within it, is poorly resolved. Here we present laser ablation – inductively coupled plasma – mass spectrometry (LA-ICP-MS) U–Pb zircon ages, coupled with petrography and geochemistry from the Izvorovo Pluton within the Sakar Unit (Strandja Zone). This pluton is composed of variably metamorphosed and deformed granites which yield crystallization ages of c. 251–256 Ma. These ages are older than the previously assumed age of the Izvorovo Pluton based on a postulated genetic relationship between the Izvorovo Pluton and Late Jurassic to Early Cretaceous metamorphism. A better understanding of units across the Strandja Zone can now be achieved, revealing two age groups of plutons within it. An extensive magmatic episode occurred c. 312–295 Ma, and a longer-lived episode between c. 275 and 230 Ma. Intrusions associated with both magmatic events were emplaced into pre-Late Carboniferous basement, and were overprinted by Early Alpine metamorphism and deformation. These two stages of magmatism can likely be attributed to changes in tectonic setting in the Strandja Zone. Such a change in tectonic setting is likely related to the collision between Gondwana-derived terranes and Laurussia, followed by either subduction of the Palaeo-Tethys Ocean beneath Laurussia or rifting in the southern margin of Laurussia, with granitoids forming in different tectonic environments.

scholarly journals Statherian (ca. 1714–1680 Ma) Extension-Related Magmatism and Deformation in the Southwestern Korean Peninsula and Its Geological Significance: Constraints from the Petrological, Structural, Geochemical and Geochronological Studies of Newly Identified Granitoids

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 557
Author(s):  
Byung-Choon Lee ◽  
Weon-Seo Kee ◽  
Uk-Hwan Byun ◽  
Sung-Won Kim
Keyword(s):  
Korean Peninsula ◽  
Tectonic Setting ◽  
Alkali Feldspar ◽  
Ductile Deformation ◽  
Southwestern Part ◽  
The North ◽  
Deformation Event ◽  
Geochemical Analyses ◽  
A Minor ◽  
T Values

In this study, petrological, structural, geochemical, and geochronological analyses of the Statherian alkali feldspar granite and porphyritic alkali feldspar granite in the southwestern part of the Korean Peninsula were conducted to examine petrogenesis of the granitoids and their tectonic setting. Zircon U-Pb dating revealed that the two granites formed around 1.71 Ga and 1.70–1.68 Ga, respectively. The results of the geochemical analyses showed that both of the granites have a high content of K2O, Nb, Ta, and Y, as well as high FeOt/MgO and Ga/Al ratios. Both granites have alkali-calcic characteristics with a ferroan composition, indicating an A-type affinity. Zircon Lu-Hf isotopic compositions yielded negative εHf(t) values (−3.5 to −10.6), indicating a derivation from ancient crustal materials. Both granite types underwent ductile deformation and exhibited a dextral sense of shear with a minor extension component. Based on field relationships and zircon U-Pb dating, it was considered that the deformation event postdated the emplacement of the alkali feldspar granite and terminated soon after the emplacement of the porphyritic alkali feldspar granite in an extensional setting. These data indicated that there were extension-related magmatic activities accompanying ductile deformation in the southwestern part of the Korean Peninsula during 1.71–1.68 Ga. The Statherian extension-related events are well correlated with those in the midwestern part of the Korean and eastern parts of the North China Craton.

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