Metallogenetic Epoch Research Articles

Metallogenetic epoch and material source of Be-pegmatite differentiated from biotite granite in Mufushan complex

The Mufushan Complex (MFSC) is a significant rare metal mineralized in the central China district and is renowned for its marked economic value of rare metal deposits. While the main rare metal mineralization (RMM) stage in the MFSC relates to the magmatic event of two-mica monzogranite, the mineralization event related to biotite monzogranite remains unknown. To fill this gap, this study focuses on porphyritic biotite monzogranite and adjacent Be-rich pegmatite samples obtained from Changqing Pegmatite No. 1, which is situated in the southeastern part of the MFSC. We subjected these samples to zircon U–Pb dating and Hf isotope analysis using laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) and utilized an electron probe X-ray microanalyzer (EPMA) and LA–ICP–MS to examine the major and trace elements present in the muscovite samples. Our findings revealed precise chronological data for the geological history of Changqing, pinpointing the intrusion age of biotite monzogranite to 145.8 ± 1.1 Ma and the crystallization age of Be-rich pegmatite to 144.9 ± 1.1 Ma, firmly situating these events within the Late Jurassic to Early Cretaceous epoch. Regarding isotopic composition, zircon εHf (t) for granite ranged from −9.29 to −5.09, and their corresponding TDM2 ranged from 1788 to 1520 Ma. Similarly, zircon εHf (t) for pegmatite ranged from −7.89 to −5.47, and their corresponding TDM2 ranged from 1699 to 1544 Ma. These isotopic signatures strongly indicate a shared origin for the initial magma of granite and pegmatite. The partial melting of the thick Lengjiaxi Group tasedimentary strata serves as a material source for RMM. The transition from granite to pegmatite exhibits remarkable constancy in the primary components of muscovite. By examining its geochemical attributes, we observed synchronous decreases in FeO, MgO, SiO2, MnO, Be, Rb, and Cs, coupled with synchronous increases in Nb and Ta contents, along with Ta/Nb values. These findings strongly imply that the Changqing biotite monzogranite and Be-rich pegmatite originate from the continuous differentiation and evolution of a common magmatic source, establishing a clear genetic relationship between them. The MFSC has its origins in three distinct stages of magmatic activity and RMM spanning from 160 Ma to 120 Ma. Considering the distribution patterns of similar pegmatite veins, the metallogenic potential observed during the biotite granite stage may serve as an external indicator of marked mineralization within large batholiths.

Metallogenic model of the Eocene Santa María and Antares Zn-Pb(-Ag) skarn deposits, Velardeña Mining District, Durango, Mexico

The Santa María and Antares Zn-Pb(-Ag) skarn deposits in the Velardeña Mining District are located in central–NW Mexico. They lie 470 m apart along the contact between Oligocene felsic intrusions and Cretaceous limestones, and were developed during prograde, retrograde, post-ore (Santa María), and late stages. Firstly, the prograde stage was formed by fluids at ~ 600 °C and 15 wt% NaCl equiv., and consists of garnet + wollastonite ± clinopyroxene and biotite ± K-feldspar assemblages. Secondly, the retrograde/ore stage was formed by fluids at 300–500 °C with salinities of 20–30 wt% CaCl2 (Santa María) and > 40 wt% NaCl equiv. (Antares). It comprises assemblages of chlorite, amphibole, epidote, calcite, scapolite, quartz, sericite, adularia, fluorite, and muscovite associated with sphalerite, pyrite, galena, pyrrhotite, arsenopyrite, chalcopyrite, and Pb-Bi-Sb sulfosalts. Thirdly, the post-ore stage was formed by fluids at ~ 400 °C and 20–30 wt.% CaCl2 and comprises poorly mineralized calcite veins. Fourthly, the late stage was formed by fluids at < 300 °C and 20–30 wt.% CaCl2 (Santa María) and ~ 15 wt% NaCl equiv. (Antares), and crystallized tetrahedrite-group minerals and pyrite + marcasite. δ18Ofluid between ~ 14‰ and 23‰ at Santa María and between ~ 12‰ and 17‰ at Antares show a less-modified magmatic affinity for mineralizing fluids at Antares; δ13Cfluid between 0‰ and –6‰ register recycling of sedimentary C. Moreover, sulfides with δ34SVCDT between –3‰ and 2‰ reveal a magmatic source for S. Altogether, these data suggest that, at Santa María, magmatic-derived fluids actively interacted with the wall rocks, whereas at Antares the fluid-rock interaction was milder. In both deposits, metal deposition was triggered by the cooling and neutralization of ore-bearing fluids with carbonate rocks. Our 40Ar/39Ar dates for adularia of ca. 37.5 Ma place the deposits within the Eocene–early Miocene metallogenetic epoch of central–NW Mexico, during which other world-class skarn-epithermal systems were emplaced (e.g., Concepción del Oro and Mazapil-Peñasquito).

C-H-O Stable Isotope, Elements and Fluid Geochemistry of Uraniferous Leucogranites in Gaudeanmus Area, Southern Central Zone, Damara Orogen, Namibia

This paper focuses on the effect of the later hydrotherm on uraniferous leucogranites and the stages of uranium mineralization. Here, we review C-H-O stable isotope, elements and fluid geochemistry of uraniferous leucogranites in Gaudeanmus, Namibia. The results show that there is significant increasing amount of rare earth element from non-mineralized to uraniferous leucogra-nites, indicating the synchronization of REE enrichment and uranium mineralization. Uranium enrichment may have close relations with Pb, Th, Co, Ni, REE in this region, so REE and U evidently exist homology. There are at least two stages of uranium mineralization by later hydrothermal alteration: firstly, due to magnatic residual high temperature and low salinity fluid, the temperature of main metallogenetic epoch ranges from 470°C to 530°C, salinity ranges from 3.55% to 9.60% NaCleq, and C, H, O stable isotope is -23‰ - -13.6‰, -53.3‰ - -46.4‰, 7.71‰ - 8.81‰, respectively. Secondly, due to superim-posed hydrothermal fluid, the temperature, salinity, and C, H, O stable isotope is 150°C - 220°C, 4.65% - 19.05% NaCleq, -20.3‰ - -3.7‰, -64.7‰ - -53.6‰, 1.49‰ - 1.99‰, respectively. The fluid for reformation is derived from postmagmatic fluid, mixed with a number of meteoric water.

Sm–Nd and Ar–Ar Isotopic Dating of the Nuri Cu–W–Mo Deposit in the Southern Gangdese, Tibet: Implications for the Porphyry‐Skarn Metallogenic System and Metallogenetic Epochs of the Eastern Gangdese

AbstractThe Nuri Cu–W–Mo deposit is a large newly explored deposit located at the southern margin of the Gangdese metallogenic belt. There are skarn and porphyry mineralizations in the deposit, but the formation age of the skarn and the relationship between the skarn and porphyry mineralizations are controversial. Constraints on the precise chronology are of fundamental importance for understanding the ore genesis of the Nuri deposit. To determine the formation age of the skarn, we chose garnets and whole rock skarn samples for Sm–Nd dating. We also selected biotite associated with potassic alteration for Ar–Ar dating to confirm the ore formation age of the porphyry mineralizations. The Sm–Nd ages of the skarn are 25.73 ± 0.92 – 25.2 ± 3.9 Ma, and the age of the potassic alteration is 24.37 ± 0.32 Ma. The results indicate that the skarn and porphyry mineralization are coeval and belong to a unified magmatic hydrothermal system. Combined with a previous molybdenite Re–Os age, we think that the hydrothermal activity of the Nuri deposit lasted for 1.2 – 2.1 Myr, which indicates that the mineralization formed rapidly. The chronologic results indicate that the Nuri deposit formed in the period of transformation from compression to extension in the late collisional stage of the collision between the Indian and Eurasian continents.

The Metallogenetic Epoch of Magnetite Deposits in Awulale Iron Belt, Western Tianshan Mountains

The Metallogenetic Epoch of Magnetite Deposits in Awulale Iron Belt, Western Tianshan Mountains

A U–Pb zircon Paleoproterozoic age for the metasedimentary host rocks and gold mineralization of the Crixás greenstone belt, Goiás, Central Brazil

The Crixás greenstone belt, Central Brazil, consists of a greenschist to low amphibolite facies metamorphic volcanosedimentary sequence that contains the sixth largest gold reserve (∼ 70 t Au, in the average 12 g/t) of Brazil and the largest gold-only deposit of Central Brazil. The gold orebodies are hosted by low-angle thrust faults within the stratigraphically upper metasedimentary rocks and are crosscut by a set of post-mineralization mafic dykes. For decades the sequence has been interpreted as a typical Archean greenstone belt of the Brazilian Shield and the gold mineralization considered either Archean or Neoproterozoic. This study shows the results of in situ U–Pb SHRIMP and LA-ICP-MS dating of detrital zircon grains from graywacke and mafic dyke samples, as well as Pb and Nd isotopic signatures of the ores. The oldest detrital zircon grains of the graywacke samples yielded U–Pb ages of 3354 ± 40 Ma and the youngest between 2209 ± 28 Ma and 2222 ± 30 Ma, which indicates a mixture of Archean and Paleoproterozoic (Rhyacian) source area and that the maximum depositional age is of ca. 2.2 Ga. Magmatic zircon of the post-mineralization mafic dykes yielded the U–Pb age of 2170 ± 17 Ma, which suggests that the basin stage, its deformation, metamorphism and mineralization were restricted to the Rhyacian and took place during a time-span of about 30–40 m.y. The paper thus provides a new insight into the age of the Crixás greenstone belt rocks and of its gold-only deposits, and reveals that Mid-Paleoproterozoic was a more widespread metallogenetic epoch related to greenstone belts of the Brazilian Precambrian Platform then previously interpreted. The observed Pb and Nd isotopic signatures of the ores suggest that metabasalts, carbonaceous schist and metagraywackes could provide the adequate sources for the ore-bodies and that the initiation of fluid circulation may have resulted by the emplacement of a high-level granite.

Metallogenetic epoch and mechanism of the tungsten ore in Yushan, Beishan orogenic belt, Gansu

Using SHRIMP zircon U-Pb dating methods and cathodoluminescence (CL) technique, we have precisely dated ore samples from tungsten ore deposit, ore-bearing volcanic-sedimentary strata and granite in the Yushan region within the east Tianshan-Beishan W-bearing zone. This study reveals Yushan tungsten ore deposit zone formed in 250 ± 9 Ma, and it is closely associated with the Permian granites and felsic volcanic rocks. This new type of tungsten ore deposit in the east Tianshan-Beishang multiple-metallogenetic province may probably be associated with the regionally right-literal shearing after the main Carboniferous collisional orogeny, and the formation of pull-apart basin and the felsic magmatism.

Isotope systematics and metallogenetic age of Zhuanghe gold deposit, Liaoning province, China

Based on the metallogenetic geology conditions, the H, O, C and S isotopic compositions were measured by MAT-251 mass spectrometer, and Pb isotope and Rb-Sr dating were carried with MAT-261 multi-acceptor mass spectrometer. The results show that the δ18O values of gold-bearing vein quartz from different levels are 1.19%–1.42%. The calculated δ18O values of ore fluids are 0.55%–0.78%, and δD values are from −8.64% to −6.66%. The calculated values of \(\delta ^{34} S_{H_2 S} \) by the δ34Spy values in quartz veins display sulfur isotope compositions from −0.053% to +0.413%. Carbon isotope compositions of carbonates are from −0.612% to 0.140%. The mole ratios of 206Pb to 204Pb, 207Pb to 204Pb and 208Pb to 204Pb in auriferous quartz vein are 16.987–17.545, 15.342–15.623, and 38.254–38.744, respectively. The age of the Zhuanghe gold deposit determined by Rb-Sr isochron of the fluid inclusions in quartzes is (143.0±5.8) Ma. These isotopic data suggest that the metallogenetic fluids are generated from magmatic hydrotherm and the origin of ore-forming matters is related to the deep-derived magmatic activities. Meanwhile, the metallogenetic epoch of the Zhuanghe gold deposit is in Yanshanian period.

Crustobody’s movement and evolution and its relationship with Cu-Au mineralization of Eastern Tianshan, Xinjiang

Eastern Tianshan, a cardinal part of Northern Xinjiang compound continental crustoblock, is located in the east of Tianshan Diwa region. By analysis of regional geological and geophysical data, and by using crustobody theory and researching methods, this region can be divided into three sectors of different crustal structure. During Proterozoic to Eopaleozoic, the spreading and closing of Northern Tianshan Sea, on the foundation of disparate continental basements of each sectors, the transversal heterogeneity of tectonic movement and evolution resulted in the diversity of crustal structure and material formations. The metallogenic evolution indicated that different geotectonic evolution periods had not only different characteristics of mineralization commodity and mineral deposit types, but also the progressive mineralization feature. In Neopaleozoic, the closing of Northern Tianshan Sea from north to south and the difference of transmeridional tectonic deformation and magmation formed in the movement constituted the different metallogenic environment in shallow crust. Furthermore, it brought on the diverse Cu-Au-polymetal mineral deposit types and metallogenetic epoch from north to south and from west to east.

The metallic ore-deposits of the Guerrero Terrane, western Mexico: an overview

The Guerrero Terrane has produced Ag, Au, Pb, Zn, Cu, and Fe from Cretaceous, Paleocene, and mid-Tertiary ore bodies, which here are considered to be those deposits hosted by Guerrero Terrane rocks regardless of their ages or genetic links. The deposits formed during the three metallogenetic epochs are described. The most important, economically, are the mid-Tertiary deposits hosted in rocks of the Guerrero Terrane, which show a characteristic distribution. Fe-skarn deposits are close to the Pacific coast. Ag–Au and base metal ore bodies are generally located along the eastern border of the Guerrero Terrane. Copper deposits are present between these two zones. Important precious and base metal epithermal deposits are aligned along the suture zone between the Guerrero Terrane and the Sierra Madre Oriental Terrane, where mid-Tertiary age igneous bodies intruded shallow levels.

Laser microarea analysis of40Ar-39Ar isochron age for Fanshan superlarge alunite deposit, Zhejiang Province, China

Laser micro-area analysis40Ar-39Ar isochron dating for pure alunite is first reported. Microarea40Ar-39Ar isochron dating results revealed that the metallogenetic epoch of Fanshan superlarge alunite deposit is 74.50 Ma, and this age is 10–20 Ma later than that of regional volcanic activity. Moreover, the potential application of micro-area analysis40Ar-39Ar isochron dating method in metallogenetic epoch studies for nonmetal deposits is also discussed.

Radiometric ages of quartz diorite bodies related to the Chichibu pyrometasomatic deposits and their relevance to the metallogenetic epoch.

The K-Ar and fission track ages of quartz diorite bodies related to the Chichibu pyrometasomatic deposits were determined. The K-Ar biotite age from C body (Eastern intrusive body) is 6.59±0.27 Ma. The fission track dating on zircon from the same sample gives the concordant age of less than 8.1 Ma. The K-Ar biotote and hornblende ages from A body (Western intrusive body) are 5.87±0, 37 and 10.5±1.5 Ma, respectively. All ages obtained here correspond to the Late Miocene. By the previous paleomagmetical work it has been determined that the C body or igneous activity of C body among many igneous phases in the mining area is responsible for ore deposition. Therefore, we conclude that the age of 6.6 Ma which is obtained from C body is the mineralization age in the mining area. It is noteworthy that the mineralization of the Chichibu mining area is Late Miocene in age, whereas most other pyrometasomatic deposits in Japan were formed in Cretaceous time.

Correlation of Precambrian Ore provinces of East Africa, India and West Australia

On the basis of the recent stratigraphic, tectonic and isotope age data, the paper attempts to classify and correlate the Precambrian tracts of Eastern Africa, South and East India and Western Australia. The stratigraphic assemblages of the Archean-Proterozoic sequences reveal a broad parallelism from the Katarchaean granulite tracts at the base up to the Upper Proterozoic Katangan-Kaimur-Cardup sequence. Six metallogenetic epochs are recognizable. The corresponding metallogenetic provinces are: (i) the Granulite province of India, Ceylon, E. Africa and W. Australia, containing deposits of graphite, ilmenite, rutile, zircon and gemstones with local Cu-Pb-Zn-Mo-La concentrations; (ii) the Nyanzian-Kavirondian-Dharwar-Kalgoorlie province containing deposits of Fe, Mn, Ni, Cr, Au etc. with minor Cu, Pb, Zn, Sb, Sn etc. (iii) the Mayumbian-Bonai-Mt. Bruce province containing Fe, Mn, Au, Cu, Pb ore deposits; (iv) the Ruzizian-Singhbhum-Gangpur province containing Cu, Pb-U, Ni, Mo, Cr, La mineralization; (v) the Kibaride-Karagwe-Ankole-Chotanagpur-Cuddapah-Bangemall province containing Sn and W mineralization, located along the contact of the batholiths as well as Pb-Cu deposits and diamondiferous diatremes, and (vi) the Katanga-Bukoban-Kaimur-Cardup province containing syngenetic Cu-Ni-Co-U mineralization.On the basis of this correlation, potential targets for further exploration are: (i) Cr in Yilgarn block (W. Australia) ; (ii) Mn, Ni, Cr, Au in Nyanzian (Tanzania and Uganda) and Fe, Mn, Cu, Pb in Mayumbian (S.E. Congo) sequences; (iii) Sn around Closepet Granite (Mysore) and Chotanagpur batholith (Bihar-Orissa); (iv) Ni in the Dharwarian ultramafites; (v) Cu and U in Bukobans (Tanzania), in Kaimurs (India) and in Cardup formation (W. Australia).

Placers of the Urals, Their Formation, Distribution and Elements of Geomorphic Prediction

AbstractThe gold, platinum and titanium placers are analyzed from the geomorphic point of view to establish future prospects as the Quaternary placers now being worked become depleted. The key to placer prospecting is seen in the historical sequence of deposition and redeposition in which older placers in turn became source areas for younger placers. The main metallogenetic epoch is associated with the Middle and Late Jurassic as well as a substantial part of the Cretaceous when intensive weathering of the regolith yielded rich placer accumulations in Mesozoic erosional-structural depressions that represent segments of the drainage net of the period. These depressions subsequently were the source areas for new placers as the drainage pattern was reoriented. In some areas crustal movements played a role as renewed erosion induced by uplifting resulted in the redeposition of metal in new placers. As the Quaternary placers become depleted, an effort is therefore recommended to focus prospecting and explorati...

Metallogenetic epochs and provinces of Bolivia

Part I. An attempt is made to solve the relationships between tectonism, magmatism and the formation of ore deposits using the Bolivian tin-province as an example. In the eastern Cordillera we are not dealing with an orthogeosyncline, but with a fault-block mountain system. Vertical movements of the fault blocks are predominant. An approximately E-W trending, old geotectonic zone of weakness divides the tin district into two parts which differ from each other in their history of development. The northern part has been uplifted against its southern counterpart. In the former, granitic plutons connected with early Variscan block faulting and folding crop out. Synorogenic Au and Sb mineralization and postorogenic W, Sn, Bi, Zn, and Pb ore deposits are connected with these. In the southern part two metallogenic epochs can be differentiated: a highly plutonic phase of Miocene age with generally weaker mineralization and a subvolcanic phase which took place during Pliocene. The Pliocene phase, which also gave rise to rich Ag mineralization, was of a greater intensity than the phases connected with the older metallogenic epochs. The genesis of the tin-silver mineralization is discussed. Within the tin-province three metallogenic epochs are recognized, with approximately the same mineralization within the same space. Part II. The metallogenic provinces of the Altiplano have been investigated with reference to their relationship to sedimentation, tectonism and magmatism, and the genesis of the deposits is discussed. The Altiplano constitutes a stable element situated between two mobile realms located to the east and west. Its subsidence began with the start of the Tertiary. During the entire Tertiary, over 15,000 m of clastic sediments were supplied to the northern portion of the basin from areas of the east and west. Copper was supplied by sulfate-bearing waters through erosion of the late Mesozoic porphyry formations from the west and was fixed as chalcocite in the Red Bed deposits. These are distributed throughout a bedded complex of approximately 9,000 m thickness, which range in age from Paleocene up till the base of the Miocene. A strong uplifted block in the NE of the basin underwent intensive erosion and peneplanation during the late Tertiary, by means of which the copper in the Red Bed-horizons was dissolved out reprecipitated again and enriched in deeper-lying horizons. Hereby, abundant chlorides and sulfates played a dominant role. The copper deposits of the Corocorotype are epigenetic and probably in principle of descendent solution-migration origin. The native copper-bearing mineralization occurs in higher horizons stratigraphically than the chalcocite mineralization. The mineral deposits are older in age than the last strong block-movement which took place during the Pliocene and by means of which they were down-faulted and consequently preserved. The polymetallic province of the Altiplano contains subvolcanic ore deposits, principally with Pb, Zn, Ag, Cu, Cd mineralization and Sb subordinately. They are associated with acid differentiated end products of Upper Tertiary volcanic activity. Transitions to the deposits of the tin-province exist in the north (Laurani and La Joya) and in the south. The polymetallic ore deposits of the Altiplano are of Pliocene age and are probably of approximately the same age as the subvolcanic Sn-W-Bi-Ag-deposits of the tin-province.

Observations on mineralogical and ore-genetic problems at Mangula

Following the author's previous paper on the broad outline of the Geology of the Mangula Copper Deposits (Jacobsen, in print), a few of the more complex problems of mineralisation are discussed. Introduction of iron, manifested by widespread, often structurally controlled martitisation, is shown to be likely. Origin of copper and iron bearing veins by lateral secretion is rejected. General silicification, potassium and boron metasomatism and intense chloritisation at Norah Mine in particular are interpreted as further proof of hydrothermal activity emanating from intruding granites. Close relationship of the mineralogical phenomena to those described recently byDarnley (1960) andVaes (1960) from Northern Rhodesia and Katanga leads to a discussion of genetic theories on the Northern Rhodesia copper deposits. Their classifications into one regional metallo-genetic epoch and province during the late algonkian Katanga-Lomagundi orogeny is proposed. Hydrothermal origin in the wake of syn-or postkinematic granite intrusions under hypothermal or even granitising conditions is accepted for all deposits within the Katanga-Lomagundi geosyncline.

Metallogenetic belts, centers, and epochs in Argentina and Chile

Three metallogenetic belts are distinguished, each related to a major geosynclinal orogenic-magmatic belt--an easterly Precambrian belt, a central belt of Hercynian deformation and mineralization, and a western Laramide belt. Late Tertiary deposits are scattered without regard to these earlier mobile belts. Quaternary volcanism along the Andean crest gave rise to sulfur and borate deposits.

わが国の鉱床生成期・生成區と、それらの二、三の問題(2)

わが国の鉱床生成期・生成區と、それらの二、三の問題(2)

Some Notes on the Metallogenetic Epochs and Provinces (1)(Special Number in Memory of the Tenth Grand Meeting of the Association for the Geological Collaboration, Democratic Scientist&apos;s Society in Japan)

Some Notes on the Metallogenetic Epochs and Provinces (1)(Special Number in Memory of the Tenth Grand Meeting of the Association for the Geological Collaboration, Democratic Scientist&apos;s Society in Japan)

Clarke Memorial Lecture. Metallogenetic epochs and ore regions in the Commonwealth of Australia.

Clarke Memorial Lecture. Metallogenetic epochs and ore regions in the Commonwealth of Australia.