Geochronology and geochemistry of the Cuihongshan Fe-polymetallic deposit, northeastern China: implications for ore genesis and tectonic setting

2018 ◽  
Vol 55 (5) ◽  
pp. 475-489 ◽  
Author(s):  
Yong Zhang ◽  
Jing-Gui Sun ◽  
Shu-Wen Xing ◽  
Zeng-Jie Zhang
Keyword(s):  
Tectonic Setting ◽  
Alkali Feldspar ◽  
Northeastern China ◽  
Late Triassic ◽  
Small Scale ◽  
Polymetallic Deposit ◽  
Central Asian ◽  
Metallogenic Belt ◽  
High K ◽  
Final Closure

The Lesser Xing’an Range is located in the eastern segment of the Central Asian Orogenic Belt. It hosts an important polymetallic metallogenic belt that contains more than 20 large- to small-scale porphyry Mo, epithermal Au, and skarn Fe-polymetallic deposits. The Cuihongshan Fe-polymetallic deposit is one of the largest polymetallic deposits in northeastern China. To better understand the formation of the Cuihongshan Fe-polymetallic deposit, we investigated the geological characteristics of the Cuihongshan deposit and applied geochemistry and geochronology to constrain the timing of the mineralization, and characteristics of the magmas. Zircon U–Pb dating of the alkali-feldspar granite and monzogranite yielded weighted mean 206Pb/238U ages of 495 ± 1.6 and 203 ± 1 Ma, respectively. Re–Os dating on molybdenite yielded an isochron age of 203.2 ± 1.4 Ma, and 40Ar/39Ar dating on phlogopite yielded an age of 203.4 ± 1.3 Ma. These data suggest that mineralization occurred during the Late Triassic, and is closely related with the monzogranite emplacement. These rocks belong to the high-K calc-alkaline and subalkaline series, are enriched in Rb, U, and Th, are depleted in Nb, Ta, and Ti, and show strong Eu anomalies, implying that they are A-type post-orogenic rocks. The Cuihongshan Fe-polymetallic formation is possibly related to an extensional environment resulting from the final closure of the Paleo-Asian Ocean.

Geochemistry, zircon geochronology, and isotopic systematics of the Zhanbuzhale granites in the East Kunlun, Qinghai Province, northwestern China: implications for the tectonic setting

2020 ◽  
Vol 57 (2) ◽  
pp. 275-291
Author(s):  
Hao-Ran Li ◽  
Ye Qian ◽  
Feng-Yue Sun ◽  
Liang Li
Keyword(s):  
Tectonic Setting ◽  
Alkali Feldspar ◽  
Northwestern China ◽  
Geochemical Data ◽  
Calc Alkaline ◽  
Qinghai Province ◽  
East Kunlun ◽  
Initial Stage ◽  
High K ◽  
Tethys Ocean

The Zhanbuzhale region, in the Eastern Kunlun Orogen of northwestern China, is characterized by large volumes of Phanerozoic granitoid rocks and is an ideal region for investigating the tectonic evolution of the Paleo-Tethys system. However, the exact timing of the final closure of the Paleo-Tethys Ocean and initial continental collision remains controversial because of a lack of precise geochronological and detailed geochemical data. In this paper, we report new zircon U–Pb ages and mineralogical, petrographic, and geochemical data for samples of Middle Triassic granodiorite and alkali feldspar granite from the Zhanbuzhale region. The zircon U–Pb ages indicate that the granodiorite and alkali feldspar granite formed at 239 and 236 Ma, respectively. The granodiorites are high-K calc-alkaline, metaluminous, high Sr content, high Sr/Y ratios, low Y content, and show adakite-like affinities. The alkali feldspar granites display high SiO2, extremely low MgO, and low Zr+Nb+Ce+Y contents as well as low Fe2O3t/MgO ratios, showing metaluminous to peraluminous and high-K calc-alkaline features. Geochemical and petrological characteristics of the alkali feldspar granites suggest that they are highly fractionated I-type granites. The granodiorites and alkali feldspar granites have zircon εHf(t) values ranging from –2.26 to –0.18, and from –2.17 to +2.18, respectively. Together with regional geological data, we propose that the Triassic (approximately 239–236 Ma) granitoids were generated during the later stages of northward subduction of the Paleo-Tethys oceanic plate, and that the initial stage of collision between the East Kunlun and the Bayan Har–Songpan Ganzi terrane occurred at approximately 236–227 Ma.

scholarly journals Zircon U–Pb geochronology and geochemistry of granitic rocks in central Mongolia

2020 ◽  
Vol 50 ◽  
pp. 23-44
Author(s):  
Boldbaatar Dolzodmaa ◽  
Yasuhito Osanai ◽  
Nobuhiko Nakano ◽  
Tatsuro Adachi
Keyword(s):  
Tectonic Setting ◽  
Granitic Rocks ◽  
Metamorphic Rocks ◽  
Calc Alkaline ◽  
Volcanic Arc ◽  
Central Mongolia ◽  
Central Asian ◽  
High K ◽  
Three Stages ◽  
Late Neoproterozoic

The Central Asian Orogenic Belt had been formed by amalgamation of voluminous subduction–accretionary complexes during the Late Neoproterozoic to the Mesozoic period. Mongolia is situated in the center of this belt. This study presents new zircon U–Pb geochronological, whole-rock major and trace element data for granitoids within central Mongolia and discusses the tectonic setting and evolution of these granitic magmas during their formation and emplacement. The zircon U–Pb ages indicate that the magmatism can be divided into three stages: the 564–532 Ma Baidrag granitoids, the 269–248 and 238–237 Ma Khangai granitoids. The 564–532 Ma Baidrag granitoids are adakitic, have an I-type affinity, and were emplaced into metamorphic rocks. In comparison, the 269–248 Ma granitoids have high-K, calc-alkaline, granodioritic compositions and are I-type granites, whereas the associated the 238–237 Ma granites have an A-type affinity. The 564–532 Ma Baidrag and 269–248 Ma Khangai granitoids also both have volcanic arc-type affinities, whereas the 238–237 Ma granites formed in a post-collisional tectonic setting. These geochronological and geochemical results suggest that arc magmatism occurred at the 564–532 Ma which might be the oldest magmatic activity in central Mongolia. Between the Baidrag and the Khangai, there might be paleo-ocean and the oceanic plate subducted beneath the Khangai and produced voluminous granite bodies during the 269–248 Ma. After the closure of the paleo-ocean, the post collisional granitoids were formed at the 238–237 Ma based on the result of later granitoids in the Khangai area.

scholarly journals The Alkaline Lamprophyres of the Dolomitic Area (Southern Alps, Italy): Markers of the Late Triassic Change from Orogenic-like to Anorogenic Magmatism

2019 ◽  
Vol 60 (6) ◽  
pp. 1263-1298 ◽  
Author(s):  
Federico Casetta ◽  
Ryan B Ickert ◽  
Darren F Mark ◽  
Costanza Bonadiman ◽  
Pier Paolo Giacomoni ◽  
...  
Keyword(s):  
Trace Element ◽  
Southern Alps ◽  
Late Triassic ◽  
Small Scale ◽  
Main Process ◽  
Calc Alkaline ◽  
Isotopic Signatures ◽  
Systematic Uncertainties ◽  
High K ◽  
Magmatic Event

AbstractWe present the first complete petrological, geochemical and geochronological characterization of the oldest lamprophyric rocks in Italy, which crop out around Predazzo (Dolomitic Area), with the aim of deciphering their relationship with Triassic magmatic events across the whole of the Southern Alps. Their Mg# of between 37 and 70, together with their trace element contents, suggests that fractional crystallization was the main process responsible for their differentiation, together with small-scale mixing, as evidenced by some complex amphibole textures. Moreover, the occurrence of primary carbonate ocelli suggests an intimate association between the alkaline lamprophyric magmas and a carbonatitic melt. 40Ar/39Ar data show that the lamprophyres were emplaced at 219·22 ± 0·73 Ma (2σ; full systematic uncertainties), around 20 Myr after the high-K calc-alkaline to shoshonitic, short-lived, Ladinian (237–238 Ma) magmatic event of the Dolomitic Area. Their trace element and Sr–Nd isotopic signatures (87Sr/86Sri = 0·7033–0·7040; 143Nd/144Ndi = 0·51260–0·51265) are probably related to a garnet–amphibole-bearing lithosphere interacting with an asthenospheric component, significantly more depleted than the mantle source of the high-K calc-alkaline to shoshonitic magmas. These features suggest that the Predazzo lamprophyres belong to the same alkaline–carbonatitic magmatic event that intruded the mantle beneath the Southern Alps (e.g. Finero peridotite) between 190 and 225 Ma. In this scenario, the Predazzo lamprophyres cannot be considered as a late-stage pulse of the orogenic-like Ladinian magmatism of the Dolomitic Area, but most probably represent a petrological bridge to the opening of the Alpine Tethys.

Lower Cretaceous alkali feldspar granites in the central part of the Great Xing’an Range, northeastern China: chronology, geochemistry and tectonic implications

2014 ◽  
Vol 152 (3) ◽  
pp. 383-399 ◽  
Author(s):  
DEXIN TIAN ◽  
WENCHUN GE ◽  
HAO YANG ◽  
GUOCHUN ZHAO ◽  
YANLONG ZHANG
Keyword(s):  
Lower Cretaceous ◽  
Tectonic Setting ◽  
Alkali Feldspar ◽  
Pacific Plate ◽  
Northeastern China ◽  
Formation Time ◽  
Granitic Rocks ◽  
Geochemical Data ◽  
Regional Geology ◽  
Great Xing’An Range

AbstractThe Mingshui–Jilasitai–Suolun area, located in the central part of the Great Xing’an Range, is characterized by large volumes of alkali feldspar granites. However, the formation time and tectonic setting of these rocks remains controversial owing to a lack of precise geochronological and detailed geochemical data. In this paper, we report new SIMS U–Pb zircon ages and mineralogical, petrographical and geochemical data for Lower Cretaceous alkali feldspar granites from the Mingshui–Jilasitai–Suolun area. The SIMS zircon dating results indicate that these granites formed at 133.6–135.9 Ma. The mineralogical, petrographical and geochemical data show that these granitic rocks belong to highly fractionated I-type granites. Combined with the regional geology data, we propose that the formation of the Lower Cretaceous alkali feldspar granitic rocks was related to an extension induced by delamination of the lithosphere that arose from subduction of the Palaeo-Pacific plate.

Geochemistry Features and the Tectonic Setting of Intrusive Rocks in Halegati, Xinjiang

2014 ◽  
Vol 962-965 ◽  
pp. 286-291
Author(s):  
Xin Li Wang ◽  
Wen Tian Mi ◽  
Yi Wei Peng ◽  
Hu Gao ◽  
Li Qiang Zhang ◽  
...  
Keyword(s):  
Close Association ◽  
Tectonic Setting ◽  
High Field Strength ◽  
Low Magnesium ◽  
Metallogenic Belt ◽  
High K ◽  
Ree Distribution ◽  
Intrusive Rocks ◽  
Type Granite ◽  
The Right

Halegati Fe-Cu deposit of skarn was located in the Boluokenu metallogenic belt. With the research of the geochemistry characteristic of granodiorites, the results showed that the rocks belonged to I type granite with the features of siliceous, metaluminous, low magnesium , high-k and alkalic. The intrusive rocks had a close association with the mineralization, which had the features of enrichment of large-ion lithophile elements (K, Rb, Ba, Th) and relative depleted in high-field strength elements (Nb, Ta, P, Ti).The intrusive rocks in Halegati had the characteristic of strongly differentiation between LREE and HREE and negative Eu anomalies obviously. The REE distribution curves had the right types. The intrusive rocks were formed in the environment of volcanic arc, which produced in the tectonic setting of supra subduction zone.

Early Permian to Late Triassic tectonics of the southern Central Asian Orogenic Belt: geochronological and geochemical constraints from gabbros and granites in the northern Alxa area, NW China

2020 ◽  
Vol 157 (12) ◽  
pp. 2089-2105
Author(s):  
Run-Wu Li ◽  
Xin Zhang ◽  
Qiang Shi ◽  
Wan-Feng Chen ◽  
Yi An ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Orogenic Belt ◽  
Central Asian Orogenic Belt ◽  
Late Triassic ◽  
Magma Source ◽  
Nw China ◽  
The North ◽  
Central Asian ◽  
Depleted Mantle ◽  
Southern Central

AbstractSituated between the North China Craton to the east and the Tarim Craton to the west, the northern Alxa area in westernmost Inner Mongolia in China occupies a key location for interpreting the late-stage tectonic evolution of the southern Central Asian Orogenic Belt. New LA-ICP-MS zircon U–Pb dating results reveal 282.2 ± 3.9 Ma gabbros and 216.3 ± 3.2 Ma granites from the Yagan metamorphic core complex in northern Alxa, NW China. The gabbros are characterized by low contents of Si, Na, K, Ti and P and high contents of Mg, Ca, Al and Fe. These gabbros have arc geochemical signatures with relative enrichments in large ion lithophile elements and depletions in high field strength elements, as well as negative εNd(t) (−0.91 to −0.54) and positive εHf(t) (2.59 to 6.37) values. These features indicate that a depleted mantle magma source metasomatized by subduction fluids/melts and contaminated by crustal materials was involved in the processes of magma migration and emplacement. The granites show high-K calc-alkaline and metaluminous to weakly peraluminous affinities, similar to A-type granites. They have positive εNd(t) (1.55 to 1.99) and εHf(t) (5.03 to 7.64) values. These features suggest that the granites were derived from the mixing of mantle and crustal sources and formed in a postcollisional tectonic setting. Considering previous studies, we infer that the final closure of the Palaeo-Asian Ocean in the central part of the southern Central Asian Orogenic Belt occurred in late Permian to Early–Middle Triassic times.

Geochemistry Characteristics of Cenozioc Alkaline-Rich Intrusions and its Forming Tectonic Setting in Jiudingshan Porphyry Cu-Mo Polymetallic Deposit, West Yunnan

2013 ◽  
Vol 868 ◽  
pp. 125-128
Author(s):  
Yan Dao ◽  
Feng Li ◽  
Wang Rong
Keyword(s):  
Tectonic Setting ◽  
High Alumina ◽  
High Potassium ◽  
Porphyry Cu ◽  
Polymetallic Deposit ◽  
Eu Anomaly ◽  
High K ◽  
Lree Enrichment ◽  
Granite Type ◽  
Geochemistry Characteristics

Geochemistry Characteristics of iudingshan Porphyry Cu-Mo Polymetallic Deposit are analyzed in the presented work. The Jiudingshan alkaline-rich porphyry is formed in Cenozoic (from 52 Ma to 29 Ma), being characterized by high potassium, rich alkali and high alumina can be attributed to high K calc alkaline series and shoshonite series, which showing LREE enrichment, HREE depletion, weak negative Eu anomaly (δEu=0.72~1.02, av.=0.86) close to the crust-mantle granite type (δEu=0.83) and mainly is formed in a post-collisional intraplate tectonic setting.

scholarly journals A Combined Geochemical and Fluid Inclusion Study of the Hongyan Cu-Polymetallic Deposit in the Eastern Hegenshan-Heihe Suture Zone, NE China: Implications for Petrogenesis, Tectonic Setting and Mineralization

2018 ◽  
Author(s):  
Chen Mao ◽  
Xinbiao Lü ◽  
Chen Chao
Keyword(s):  
Oxygen Fugacity ◽  
Fractional Crystallization ◽  
Tectonic Setting ◽  
Source Region ◽  
Alkali Feldspar ◽  
Suture Zone ◽  
Fluid Inclusion Study ◽  
Hydrothermal Mineralization ◽  
Polymetallic Deposit ◽  
Magmatic Oxygen Fugacity

In order to study the petrogenesis and tectonic setting of Permian A-type granites and their relationships with hydrothermal mineralization along the Hegenshan-Heihe suture zone (HHSZ) in northeastern China, we select the newly discovered Hongyan Cu-polymetallic deposit in the northeastern part of the HHSZ that develops three stages of mineralization associated with the Shanshenfu alkali-feldspar granite (SAFG). The zircon U-Pb dating and whole rock geochemistry suggest that the SAFG is a typical A-type granite formed in the Early Permian. The zircon Hf isotopes and trace elements suggest that the SAFG has high Ti-in-zircon temperature (721–990℃), high magmatic oxygen fugacity and largely positive εHf(t) (+6.0 to +9.9). Therefore, we propose that the SAFG was derived from the crustal assimilation and fractional crystallization of the charnockitized juvenile crust. The high oxygen fugacity favors the chalcophile elements (e.g., Cu, Au, Ag) of the source region enriched in the fluid phases after magmatic fractional crystallization, consequently facilitating subsequent hydrothermal mineralization, which is also consistent with the characteristics of ore-forming fluids that changed from the initial high temperature, high salinity, high fO2 and CO2-rich magmatic-hydrothermal fluids of stage I to CO2-poor, dilute, and cooling meteoric fluids of stage III. Combined with regional geological background, the Permian A2-type granites along the HHSZ can be formed in post-collisional slab break-off process. In subsequent exploration for hydrothermal deposits along the HHSZ, the Permian A-type granites with arc-related juvenile crustal source and high fO2 have great potential and need more attention.

scholarly journals Petrogenesis and Tectonic Setting of the Highly Fractionated Junye Granitic Intrusion in the Yiliu Tungsten Polymetallic Deposit, Guangdong Province, South China: Constraints from Geochemistry and Sr-Nd-Pb-Hf Isotopes

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 631
Author(s):  
Tao Wu ◽  
Zhilong Huang ◽  
Mu Yang ◽  
Dexian Zhang ◽  
Jiawei Zhang ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
South China ◽  
Tectonic Setting ◽  
Granitic Magma ◽  
Geochemical Data ◽  
Metallogenic Province ◽  
Polymetallic Deposit ◽  
South Central ◽  
High K

The Yiliu tungsten polymetallic deposit, located in the south central portion of the Nanling nonferrous metal metallogenic province in South China, is an area with common Yanshanian tectonothermal events. Early Yanshanian magmatism leads to the emplacement of voluminous tungsten-bearing granite intrusions, such as the Baoshan, Benggangling and Junye plutons, which are considered temporally and spatially associated with W-polymetallic mineralization in the Yiliu region. Here, we investigate the basic geological and petrological characteristics of the Junye granites, and present major and trace element geochemical data and bulk-rock Sr-Nd-Pb-Hf isotopic data to gain insight into the petrogenesis and tectonic setting of granitic intrusions in the region. The Junye granites are high-K calc-alkaline and metaluminous to weakly peraluminous [A/CNK = molar ratios of Al2O3/(CaO + Na2O + K2O) = 0.97–1.02] with enrichment in SiO2 (75.68–76.44 wt.%), relatively high total alkalis (K2O + Na2O = 8.06–8.45 wt.%) with K2O/Na2O ratios ranging from 1.12 to 1.42, and moderate Al2O3 (12.62–13.00 wt.%), but low in P2O5 (<0.01 wt.%), MgO (0.02–0.04 wt.%), CaO (0.78–0.95 wt.%) and Fe2O3T (0.93–1.07 wt.%). They show spectacular tetrad effect REE (rare earth element) patterns with low ΣREE content (53.2–145.3 ppm), negative Eu anomalies (δEu = 0.09–0.17) and slight enrichment of LREEs (light rare earth elements) relative to HREEs (heavy rare earth elements). The granites are enriched in Rb (481–860 ppm), Th (16.2–46.1 ppm) and U (25.4–40.8 ppm) but depleted in Ba (1.0–5.8 ppm), Sr (11.1–23.4 ppm), P (9.5–26.7 ppm) and Ti (241–393 ppm). All geochemical features lead us to interpret the Junye granites as highly fractionated I-type granites. These granites underwent intense interaction between highly evolved magma and volatile-rich hydrothermal fluids during the late stage of formation, and accompanied fractional crystallization of biotite, plagioclase and accessory minerals, such as apatite, monazite and allanite. Additionally, the granites show uniform Nd isotopic ratios with calculated εNd (152 Ma) values of −8.28 to −8.91 and Nd model age (TDM2) of 1645 to 1698 Ma, stable age-corrected initial Pb isotopic compositions with (206Pb/204Pb)i of 18.646–19.010, (207Pb/204Pb)i of 15.767–15.786 and (208Pb/204Pb)i of 39.113–39.159, respectively, and homogeneous Hf isotopic values yielding εHf (152 Ma) values from −6.9 to −9.5 with TDM2 ages of 1680 to 2214 Ma, collectively suggesting that the granitic magma was probably derived from the remelting of ancient infracrustal materials in the basement of the Nanling region. Consequently, we consider that the Junye granites are the products of partial melting of Paleoproterozoic infracrustal medium- to high-K metamorphic basaltic rocks in the Cathaysia Block, which was caused by the underplating of coeval mantle basaltic magmas that provided abundant heat energy for melting in a tectonic setting, with lithospheric extension and thinning during the late Jurassic period.

Facies and small-scale geometries of the Late Triassic Kawr Platform, Sultanate of Oman

2001 ◽  
Vol 28 (1) ◽  
pp. 155-157
Author(s):  
Elias Samankassou ◽  
M. Bernecker ◽  
Erik Flügel
Keyword(s):  
Late Triassic ◽  
Small Scale ◽  
Sultanate Of Oman
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