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1.
New 40Ar/39Ar thermochronology results and thermal modeling support the hypothesis of Hollister et al. (2004), that reheating of the mid-Cretaceous Ecstall pluton by intrusion of the Coast Mountains Batholith (CMB) was responsible for spatially variable remagnetization of the Ecstall pluton. 40Ar/39Ar ages from hornblende and biotite from 12 locations along the Skeena River across the northern part of the Ecstall pluton decrease with proximity to the Quottoon plutonic complex, the nearest member of the CMB to the Ecstall pluton. The oldest 40Ar/39Ar ages are found farthest from the Quottoon plutonic complex, and are 90 ± 3 Ma for hornblende, and 77.9 ± 1.2 Ma for biotite. The youngest 40Ar/39Ar ages are found closest to the Quottoon plutonic complex, and are 51.6 ± 1.2 Ma for hornblende, and 45.3 ± 1.7 Ma for biotite. No obvious relationship between grain size and age is seen in the Ecstall pluton biotites. Spatial trends in 40Ar/39Ar ages are consistent with model results for reheating by a thermal wall at the location of the Quottoon plutonic complex. Although no unique solution is suggested, our results indicate that the most appropriate thermal history for the Ecstall pluton includes both reheating and northeast side up tilting of the Ecstall pluton associated with intrusion of the Quottoon plutonic complex. Estimates of northward translation from shallow paleomagnetic inclinations in the western part of the Ecstall pluton are reduced to ∼3000 km, consistent with the Baja-BC hypothesis, when northeast side up tilting is accounted for.  相似文献   

2.
Vertical displacements on the SW–NE Têt fault (Eastern Pyrenees Axial Zone, France), which separates the Variscan Canigou-Carança and Mont-Louis massifs, were constrained using a thermochronologic multi-method approach. 40Ar/39Ar data from the granitic Mont-Louis massif record its Variscan cooling history and reveal no ages younger than Early Cretaceous, while the Canigou-Carança gneiss massif records systematically younger 40Ar/39Ar ages. These younger 40Ar/39Ar ages in the Canigou-Carança gneiss massif are the result of partial to total rejuvenation of argon isotopic systems related to a thermal flow coeval with the Cretaceous HT-BP metamorphism in the North Pyrenean Zone. Only the deepest rocks from the Canigou-Carança suffered this extensive Mid-Cretaceous thermal overprint probably due to differential burial around 4 km at that time. The post Mid-Cretaceous vertical displacements along the Têt fault are recorded by “low” temperature thermochronology using K-feldspar 40Ar/39Ar, zircon and apatite fission track and (U–Th)/He datings. The Mont-Louis granite samples experienced a long period of protracted cooling reflecting a lack of thermo-tectonic activity in this area from Late Palaeozoic to Early Cenozoic, followed by cooling from 55–60 Ma to Late Eocene at a mean rate of 15–20°C/Ma in the final stage. This cooling stage corresponds to Têt fault reactivation with a reversed component, promoting exhumation of the Mont-Louis roof zone contemporaneously with the south-vergent Pyrenean thrusting. In the Canigou-Carança massif, the main cooling event occurred from 32 to 18 Ma at a maximum rate of 30°C/Ma during Early Oligocene followed by a more moderate rate of 3°C/Ma from Late Oligocene to Early Burdigalian, coeval with the normal reactivation of the Têt fault in brittle conditions that accommodated the final exhumation of the massif during the opening of the Gulf of Lion.  相似文献   

3.
The Lukinda dunite–troctolite–gabbro massif in the Selenga–Stanovoy superterrane on the southeastern framing of the Siberian Platform was earlier considered Precambrian. The performed 40Ar/39Ar dating of the massif plagioclase yielded an Early Permian age (285 ± 7.5 Ma). The main specific petrochemical features of the intrusion rocks during their crystallization differentiation are an increase in SiO2 and CaO contents and a decrease in FeOtot content, with TiO2 content remaining low and showing minor variations. A specific geochemical feature of the Lukinda massif ultrabasite–basites is a slight domination of LREE over HREE, with (La/Yb)N= 1.0–8.2. The depletion of the massif rocks in LILE (except for Sr and Ba), REE, and HFSE suggests that the massif formed on an active continental margin.  相似文献   

4.
The Piaoak tin-bearing granite-leucogranites located in the Caobang Province of Northern Vietnam compose a stock-like hypabyssal body. Host rocks are represented by Early Devonian carbonate sequences and Early Triassic ??black?? shales. The geochronological age of the Piaoak granite-leucogranites corresponds to the Late Cretaceous: T = 83.5 ± 6.2 Ma, 87Rb/86Sr method; T = 89.7 ± 1.0 Ma, 39Ar/40Ar method. The massif has a simple basic to acid order: two-mica and muscovite granite-leucogranite ?? raremetal aplites, pegmatites ?? tin-bearing greisens and hydrothermal veins. The petrographic and microstructural studies revealed a sharp change in crystallization conditions of the granite-leucogranite magma at the late magmatic stage and formation of muscovite via incongruent melting of protolithionite. The study of melt and coexisting fluid inclusions showed that solidus crystallization occurred under fluid-saturated conditions at 635?C600°C. In composition, the granite-leucogranites of the Piaoak Massif correspond to the raremetal-plumasite geochemical type (according to L.V. Tauson), and reach Li-F facies in terms of their rare-element composition. The composition of aplites and pegmatites demonstrates that granite-leucogranite magma did not accumulate lithophile and volatile components in the residual melt during differentiation, but was initially enriched in rare-metals. It is most probable that the melt was generated from Proterozoic lithotectonic complexes and overlaying Lower Triassic ??black?? shales.  相似文献   

5.
New data on the geology and petrochemistry of rocks from the Klyuchevskoi massif located in the central part of the Aramil’sko-Sukhtelinskaya zone of the South Urals are reported in this paper. According to some geological, petrographic, and geochemical characteristics, rocks of the Kukushkinskii Complex, including the Klyuchevskoi massif, are very different from gabbroids of other formation types of the South Urals, but demonstrate significant similarity to rocks of the gabbro-granite formation of the Magnitogorsk Megazone. The relationship of the Klyuchevskoi massif to the gabbro-granite formation allowed us to combine the South Uralian and Middle Uralian segments of the Early Carboniferous rift into a general submeridional structure.  相似文献   

6.
The Gromadnen-Vurguveem peridotite-gabbro massif is confined to one of the largest ophiolite complex of western Chukotka and composed mainly of intrusive rocks. This paper reports the first comprehensive compositional data for its plutonic rocks (petrochemistry, geochemistry, and compositions of minerals). In terms of petrography, two groups of rocks can be distinguished in the Gromadnen-Vurguveem peridotite-gabbro massif. The first group includes leucocratic gabbroids (mostly gabbronorites), composing most of the massif. The second group includes olivine-bearing cumulate rocks: olivine gabbros, troctolites, plagioclase-bearing dunites, and amphibolized wehrlites. The major element variations in these rocks suggest their affiliation to low-titanium, low-potassium, and high-alumina plutonic derivatives of island-arc magmatism. According to geochemical characteristics (distribution of REEs and indicator incompatible elements), the gabbroids of the first group are akin to both island-arc tholeiites and boninites. The olivine-bearing rocks of the second groups show boninitic affinity. Based on these observations, it was concluded that the intrusive complex of the Gromadnen-Vurguveem massif was formed during an early stage of the development of an ensimatic island arc.  相似文献   

7.
During the Cretaceous, the South China Block (SCB) experienced a widely distributed extensional event including numerous plutons emplacement and basin opening. Investigations on the tectonic regime coeval with pluton emplacement, and emplacement mechanism of the pluton remain relatively rare in the SCB. In order to address these questions, a multidisciplinary approach, including field structural and petrographic observations, anisotropy magnetic susceptibility (AMS) and paleomagnetic analyses, was carried out on the Qingyang–Jiuhua granitic massif which intrudes into the Lower Yangtze fold belt in the northeastern part of the SCB. The Qingyang–Jiuhua massif is composed of the granodioritic Qingyang and monzogranitic Jiuhua plutons dated by zircon U–Pb method at ca. 142 Ma, and ca. 131 Ma, respectively. Our structural observations show that the intrusion of the Qingyang–Jiuhua massif does not modify the fold strike. A weak ductile deformation of the country rocks and granitoid can be only observed in the boundary zone with limited contact metamorphism. In the contact aureole of the massif, the foliation follows the pluton contour, and the mineral lineation is rare. When present, it exhibits a down-dip attitude. Field and microstructural observations indicate isotropic magmatic textures in most parts of the massif. The AMS analysis of 93 sites reveals weak values for the anisotropy degree (PJ < 1.2) and oblate magnetic fabric dominance (T > 0) for most of the measured samples. Two principal foliation patterns are identified: horizontal foliations in the center of the plutons, and vertical foliations on the boundaries. Magnetic lineation strike is largely scattered, and weakly inclined at the scale of the entire massif. The paleomagnetic investigations indicate that (a) the younger Jiuhua pluton did not produce a remagnetization in the older Qingyang pluton, (b) no relative movement can be observed between these two plutons, (c) the entire massif did not experience any important relative movement with respect to South China, considering the paleomagnetic uncertainties. Integrating the newly obtained results with previous observations, our study favors a permissive emplacement mechanism for the two plutons, i.e. vertical magma intrusion into an opening space controlled by the NW–SE brittle stretching of the upper crust, which is in agreement with a weak extensional regional tectonic framework of the SCB.  相似文献   

8.
安徽月山岩体的40Ar/39Ar年龄及与其有关的成矿时代估计   总被引：13，自引：0，他引：13  
安徽月山岩体是长江中下游钢铁成矿带中的一个重要含矿岩体.我们对该岩体的角闪石和黑云母进行了40Ar/39Ar年龄测定.角闪石的未扰动年龄谱给出岩体侵位年龄为136Ma.根据黑云母的扰动年龄谱,估计岩体从浸位到矿化（晚期热液作用）的时间间隔不少于9Ma.月山岩体的年龄测定结果以及前人对长江中下游其它含铜岩体的年龄测定结果表明,该区所有铜矿化岩体均形成于136Ma前,且产出于沿江构造单元内.此外,月山岩体的研究还表明,对中酸性岩的年龄测定,封闭温度高的角闪石是较理想的样品,在解释与矿化有关或热液作用发育的岩体的黑云母K-Ar结果时,必须持慎重态度.  相似文献   

9.
Zircon UPb dating by SIMS of the Mont-Louis granite yields an age of 305±5 Ma, intrepreted to reflect the igneous emplacement age of the massif. It is in agreement with the Hercynian syntectonic character of Pyrenees granite. 40Ar/39Ar on hornblende, biotite and K-feldspar permit, to estimate the massif cooling. A rapid temperature decrease (≈30 °C/Ma) is revealed from Westphalian to Late Stephanian, coeval with the emplacement of a laccolithe in the upper crust. Then, the cooling rate decreases to ≈1 °C/Ma. This would be consistent with a long time residence for the pluton from the Late Palaeozoic to the Early Cainozoic at 6–8 km depth. To cite this article: O. Maurel et al., C. R. Geoscience 336 (2004).  相似文献   

10.
A Cu-bearing skarn zone occurs north of the Shayvar Mountain in northwestern Iran. Skarn-type metasomatic alteration and mineralization occur along the contact between Upper Cretaceous impure carbonates and a Miocene Cu-bearing granitic stock. Both endoskarn and exoskarn developed in the rocks. Exoskarn is the principal skarn zone and is enclosed by a skarnoid–hornfelsic zone. Skarn formation occured during stages: (1) prograde, (2) middle stage and (3) late stage. In the prograde stage, there were two main processes: (a) metamorphic–bimetasomatic and (b) prograde metasomatic. The metamorphic process began immediately after intrusion of the pluton into the enclosing impure carbonates. The prograde metasomatic stage commenced with segregation and evolution of a fluid phase in the pluton and movement into fractures and micro-fractures in the skarnoid–hornfelsic rocks developed in a metamorphic zone. The introduction of considerable amounts of Fe, Si and Mg led to the development of voluminous medium- to coarse-grained anhydrous calc-silicates. During the middle stage, the previously formed skarn zones were affected by intense multiple hydrofracturing in the Cu-bearing stock. In addition to Fe, Si and Mg, substantial amounts of Cu, Pb and Zn, along with volatile components such as H2S and CO2 were added to the skarn system. Consequently, substantial amounts of hydrous calc-silicates (epidote, tremolite–actinolite), sulfides (pyrite, chalcopyrite and molybdenite), oxides (magnetite, hematite) and carbonates (calcite) replaced the anhydrous calc-silicates. The retrograde stage was synchronous with the incursion of relatively low-temperature, more oxidized fluids into skarn system, resulting in partial alteration of the early-formed calc-silicates and development of a series of very fine-grained aggregates of chlorite, clay, hematite and calcite. Zircon grains from the endoskarn zone provide constraints on the timing of solidification of the granite stock (9.91 ± 0.31 Ma) that caused mineralization in the Anjerd area. One sample of primary hornblende from the monzogranitic Shayvar batholith has an 40Ar/39Ar age of 26.54 ± 0.65 Ma and indicates that intrusion of the Miocene stock and associated Cu skarn formation occurred a considerable time after intrusion of the batholith.  相似文献   

11.
《Gondwana Research》2001,4(3):541-550
Since the late 1980s, it has been hypothesized that the wide range of apparent argon ages seen within single K-feldspar samples might be due to a distribution of diffusion domain sizes within the mineral. To test and apply this idea, an analytical technique that combines conventional laboratory degassing experiments (resistance heating) with numerical inversion procedures has been developed to extract cooling history information from feldspars. A key part of the method involves careful control of temperature in the laboratory to constrain the diffusion parameters of the feldspar samples. In our study, we have K-feldspar data from single crystals that mimic the types of data seen in classic resistance heater fusion experiments. Our step-heating data are based on using a continuous argon-ion laser with no direct control on temperature. However, with only a single added free parameter in the model, we show that it is possible to analyze this data in the multi-domain style, and make some simple inferences on the nature of the cooling history of the Carion pluton in central Madagascar. The Carion granitic pluton in central Madagascar was intruded into warm continental crust following orogenic events related to the final amalgamation of Gondwana. U-Pb SHRIMP dating of the pluton yields an emplacement age of 532.1 ± 5.2 Ma followed by relatively slow cooling as constrained by 40Ar/39Ar ages on hornblende, biotite and K-feldspar. Four hornblende samples yielded a mean 40Ar/39Ar age of 512.7 ± 2.6 Ma. A biotite sample yielded an age of 478.9 ± 1.0 Ma and modeled K-feldspar ages show cooling from 350° C at 466 Ma to 100° C by 410 Ma. Collectively, the data suggest that the pluton cooled from 850° C at 532.1 ± 5.2 (U-Pb zircon) Ma to 500° C at 512.7 ± 2.6 Ma (40Ar/39Ar hornblende), or approximately 18 °C/Ma slowing to ∼4 °C/Ma between 512 Ma and 478 Ma and finally to about 3°C/Ma between 478 and 410 Ma.  相似文献   

12.
Detailed 40Ar/39Ar geochronology on single grains of muscovite was performed in the Variscan Tanneron Massif (SE France) to determine the precise timing of the post-collisional exhumation processes. Thirty-two plateau ages, obtained on metamorphic and magmatic rocks sampled along an east–west transect through the massif, vary from 302 ± 2 to 321 ± 2 Ma, and reveal a heterogeneous exhumation of the lower crust that lasted about 20 Ma during late Carboniferous. In the eastern part of the massif, the closure of the K–Ar isotopic system is at 311–315 Ma, whereas in the middle part of the massif it closes earlier at 317–321 Ma. These cooling paths are likely to be the result of differential exhumation processes of distinct crustal blocks controlled by a major ductile fault, the La Moure fault that separates both domains. In the western part of the massif, the ages decrease from 318 to 303 Ma approaching the Rouet granite, which provides the youngest age at 303.6 ± 1.2 Ma. This age distribution can be explained by the occurrence of a thermal structure spatially associated to the magmatic complex. These ages argue in favour of a cooling of the magmatic body at around 15 Ma after the country rocks in the western Tanneron. The emplacement of the Rouet granite in the core of an antiform is responsible for recrystallization and post-isotopic closure disturbances of the K–Ar chronometer in the muscovite from the host rocks. These new 40Ar/39Ar ages clearly outline that at least two different processes may contribute to the exhumation of the lower crust in the later stage of collision. During the first stage between 320 and 310 Ma, the differential motion of tectonic blocks limited by ductile shear zones controls the post-collisional exhumation. This event could be related to orogen parallel shearing associated with crustal-scale strike-slip faults and regional folding. The final exhumation stages at around 300 Ma take place within the tectonic doming associated to magmatic intrusions in the core of antiformal structures. Local ductile to brittle normal faulting is coeval to Upper Carboniferous intracontinental basins opening.  相似文献   

13.
The island of Sark (Channel Islands, UK) exposes syntectonic plutons and country rock gneisses within a Precambrian (Cadomian) continental arc. This Sark arc complex records sequential pulses of magmatism over a period of 7 Ma (ca. 616–609 Ma). The earliest intrusion (ca. 616 Ma) was a composite sill that shows an ultramafic base overlain by a magma-mingled net vein complex subsequently deformed at near-solidus temperatures into the amphibolitic and tonalitic Tintageu banded gneisses. The deformation was synchronous with D2 deformation of the paragneissic envelope, with both intrusion and country rock showing flat, top-to-the-south LS fabrics. Later plutonism injected three homogeneous quartz diorite–granodiorite sheets: the Creux–Moulin pluton (150–250 m; ca. 614 Ma), the Little Sark pluton (>700 m; 611 Ma), and the Northern pluton (>500 m; 609 Ma). Similar but thinner sheets in the south (Derrible–Hogsback–Dixcart) and west (Port es Saies–Brecqhou) are interpreted as offshoots from the Creux–Moulin pluton and Little Sark pluton, respectively. All these plutons show the same LS fabric seen in the older gneisses, with rare magmatic fabrics and common solid state fabrics recording syntectonic crystallisation and cooling. The cooling rate increased rapidly with decreasing crystallisation age: >9 Ma for the oldest intrusion to cool to lower amphibolite conditions, 7–8 Ma for the Creux Moulin pluton, 5–6 Ma for the Little Sark pluton, and <3 Ma for the Northern pluton. This cooling pattern is interpreted as recording extensional exhumation during D2. The initiation of the D2 event is suggested to have been a response to the intrusion of the Tintageu magma which promoted a rapid increase in strain rate (>10−14 s−1) that focussed extensional deformation into the Sark area. The increased rates of extension allowed ingress of the subsequent quartz diorite–granodiorite sheets, although strain rate slowly declined as the whole complex cooled during exhumation. The regional architecture of syntectonic Cadomian arc complexes includes flat-lying “Sark-type” and steep “Guernsey-type” domains produced synchronously in shear zone networks induced by oblique subduction: a pattern seen in other continental arcs such as that running from Alaska to California.  相似文献   

14.
《Gondwana Research》2014,25(3-4):1031-1037
Although the Sibumasu terrane in Asia was previously considered to be composed of Phanerozoic rocks with Cambrian crystalline basement, no reliable or direct radiometric dating evidences of such crystalline basement was ever reported. Our new in-situ zircon U/Pb dating of the Khao Tao orthogneiss yields a concordant age of 501.5 ± 7.5 Ma (2σ), which provides the first robust evidence for the Cambrian crust in Upper Peninsula of Thailand. The zircon εHf(T) values range from + 3.7 to − 6.1 with model ages (TCDM) of 1244–1827 Ma, suggests a mixed crust-mantle source. The chemical similarity and spatial continuity of the Khao Tao orthogneiss with other pre-Neotethys marginal Eurasian and Sibumasu granitoids indicate the linear paleogeographic association under a similar magmatic arc-related regime along the Gondwana India–Australia margin as part of the Pan-African Orogeny system.  相似文献   

15.
The Lugokan ore cluster is located in the southeastern part of Transbaikalia within the Aga–Borzya structural–formational zone of the Mongol–Okhotsk orogenic belt. The 40Ar/39Ar dating of K-bearing minerals of syngenetic to ore parageneses has been carried out applying stepwise heating technique: it has been demonstrated that the earliest gold-ore mineral associations are Au–pyrite–arsenopyrite (163 ±1.9 Ma) and Au–chalcopyrite (160 ±2 Ma). The later parageneses encompass the Au–polymetallic (156.3 ± 1.8 Ma) and Au–Bi (155.9 ± 4.5 Ma) one. By their ages and position in the general scheme of the Late Jurassic magmatism of Eastern Transbaikalia, the Lugokan’s ore cluster gold-bearing mineral associations corresponds to the time of intrusion of the Shakhtama pluton (161 Ma) and the Porphyry Complex (159–155 Ma).  相似文献   

16.
The Frankenstein gabbro complex in the northern Odenwald/FR Germany is one of the Hercynian plutonic bodies of the Saxothuringian zone in the Variscan belt.87Sr/86Sr isotopic investigations on pyroxene,40Ar/39Ar age determinations on hornblendes, plagioclases, biotites and pyroxenes and207Pb/206Pb dating on single zircon crystals have been carried out. The87Sr/86Sr initial ratio of the gabbro (0.70380) indicates uncontaminated derivation of the magma from the mantle. The results on hornblendes, plagioclases and zircons establish the isotopic age of intrusion and the mode of cooling. Pyroxene and biotite data indicate disturbed K-Ar systems of these minerals. The average ages of the hornblendes (363±7 Ma), of the plagioclases (359±3 Ma) and of the zircons (362 ±9 Ma) agree within the 1-sigma levels and constrain the early history of the plutonic intrusion at the turn from Devonian to Carboniferous times. These minerals must have been cooled below their closure temperatures within a time-interval shorter than the error margins of 10 Ma. The ages therefore are, unlike those of the neighbouring Bergsträßer Odenwald, not long-time cooling ages due to largescale and slow geological uplift of the crustal segment. Instead, they will closely estimate the time of intrusion of the Frankenstein pluton into a shallow crustal level. The hiatus of about 20 Ma compared to the average ages of the crystalline rocks of the Bergsträßer Odenwald in the south characterizes the mafic Frankenstein pluton as a separated unit of the Odenwald crystalline, and underlines the importance of the Carboniferous tectonic fault zone in-between. The present data set clearly demonstrates the importance of the applied combination of methods and techniques to constrain the history of intrusion and cooling of mafic plutonic rocks.  相似文献   

17.
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18.
清原树基沟英云闪长岩40Ar/39Ar年龄谱   总被引：7，自引：0，他引：7       下载免费PDF全文
清原太古代花岗-绿岩地体位于华北断块北缘,辽宁地块铁岭-靖宇古隆起中部,分布面积约8,000平方公里,花岗岩与绿岩出露面积比为2.5:1。绿岩地层自下而上分为石棚子组、红透山组和南天门组。石棚子组与红透山组整合接触,南天门组不整合于红透山组之上。  相似文献   

19.
Left-lateral motion along the Ailao Shan–Red River (ASRR) Shear Zone has been widely advocated to be the result of the collision between the Indian and Eurasian plates and to account for sea-floor spreading in the South China Sea. Our new 40Ar/39Ar data on the south-easternmost outcrop of the Day Nui Con Voi metamorphic massif, northern Vietnam, suggest that the exhumation of metamorphic massif by shearing along the ASRR zone began ∼27 Ma and lasted until ∼22 Ma. A perfect correlation between location and cooling path for the samples along the shear zone suggests that the transtensional deformation may have propagated northwestward at a rate of ∼6 cm y−1. Such a good correlation also indicates that the onset of the left-lateral movement of the shear zone may have occurred later than ∼27.5 Ma. This conclusion is consistent with our previous interpretation that collision-induced southeastward extrusion of Indochina along the ASRR Shear Zone postdates the opening of the South China Sea, and that extrusion tectonics in SE China may not be responsible for the opening of the South China Sea.  相似文献   

20.
The Dzheltula alkaline massif is located in the Tyrkanda ore region of the Chara–Aldan metallogenic zone of the Aldan–Stanovy Shield (South Yakutia). The region contains separate placer gold objects, which are being explored at the present time, and ore-bearing Mesozoic alkaline intrusions, which are weakly studied due to their poor accessibility. The Dzheltula massif (DM) is the largest exposed multiple-ring intrusion within the Tyrkanda ore region; therefore, it is considered as a typical object for geological, petrological, geochronological, and metallogenic studies. The DM consists of five magmatic phases of syenite composition. 40Ar–39Ar dating has established that the crystallization age of the oldest phase, the leucocratic syenite porphyry (pulaskite), is 121.1 ± 1.3 Ma. The crystallization age of the cross-cutting phases represented by syenite–porphyry dikes (laurvikites and pulaskites) ranges from 120.1 ± 2 to 118.3 ± 2.1 Ma. The youngest phase of the massif, trachyte, crystallized at 115.5 ± 1.6 Ma. According to the mineralogical and geochemical studies, two types of ore mineralization, namely gold and uranium–thorium–rare-earth (U–Th–REE), are established within the DM. The gold mineralization was found in the quartz–chlorite–pyritized metasomatites. It is confined to the NNE- and NNW-trending fault zones and coincides with the strike of the syenite porphyry dike belt. Uranium–thorium–rare-earth mineralization has been established in the quartz–feldspathic metasomatites localized in the outer contact of the massif. The juxtaposition of mineralization of different types in some zones of the Dzheltula syenite massif significantly increases the ore potential of the studied object within the Tyrkanda ore region.  相似文献   

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