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206 Pb/ 238 U ages and relative 2σ error bars of zircons from an ash bed at the Triassic-Jurassic boundary in the Utctubamba Valley, northern Peru (data from Schaltegger et al., 2008, and Schoene et al., 2010b). The zircons on the left-hand side of the plot were analyzed using the 205-235 UNIGE tracer, whereas those on the right-hand side were analyzed using the ET2535 spike: note the difference of the associated errors bars in the two cases. Also shown are zircons from the North Mountain Basalt of the CAMP province analyzed with the ET2535 tracer. Note that whereas zircons from the felsic magma chamber, whose eruption has produced the Utcubamba ash layer, spread an age range of about 600 ka, those of the North Mountain Basalt have indistinguishable ages. This is the result of magmatic recycling at the X00-ka scale to produce felsic magmas in the crust as opposed to the lack of magmatic refinement in basaltic magmas.
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Determining the absolute duration of magmatic-hydrothermal events leading to the formation of porphyry
systems (i.e., including porphyry copper, skarn, and epithermal deposits) is one of the key questions in ore
geology. This is so because the duration of magmatic-hydrothermal events in porphyry systems is instrumental
to the development of genetic...
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The link between observed episodicity in ore deposit formation and preservation and the supercontinent cycle is well established, but this general framework has not, however, been able to explain a lack of deposits associated with some accretionary orogens during specific periods of Earth history. Here we show that there are intriguing correlations...
The Zn-Pb-Cu(-Ag±Au) San Martín deposit in northwestern Zacatecas is one of the most economically important and biggest skarns in Mexico. Mineral associations in this deposit belong to the sulfide skarn type (with rather " classical " prograde and retrograde zones) and contain peripheral subepithermal to epithermal veins. Re-Os ages were obtained f...
The Peña Colorada mineralized area
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Two 40Ar/39Ar ages at 24.50 ± 0.07 and 23.46 ± 0.26 Ma (latest Oligocene) were obtained in this paper for adularia separates from vein material of the Cinco Minas low sulfidation epithermal deposit in Jalisco, southwestern Mexico. Such ages confirm the migration of metallogenic activity along with volcanism as the Sierra Madre Occidental migrated s...
In Cajamarca and La Libertad regions, north of Perú, are located important mineral deposits like Tantahuatay, Cerro Corona, Yanacocha, Minas Conga, La Arena and others; which belong to metallogenic belts XXI-A, XXI-B and XX. The present research has been developed based on the information collected in the field, as well as the geochemical, isotopic...
Citations
... Hydrothermal deposits are typically understood as zoned and dynamically evolving geological objects where similar processes, including mineral precipitation, repeatedly occur over space and time as systems incrementally develop (Chiaradia et al., 2013;Chelle-Michou and Schaltegger, 2023). The final size and internal architecture of a deposit can thus reflect the protracted formation of small ore bodies individually produced in a relatively short timeframe but collectively accumulated over potentially longer timescales. ...
Mississippi Valley-type (MVT) deposits contain about 20% of global zinc resources and host critical raw materials
crucial to the development of green technologies. Despite their economic and strategic importance, there is a lack
of consensus on the duration of mineralizing fluid flow events in MVT systems. This study couples in-situ U-Pb
dating with Sr-isotope and trace element analysis of syn- and post-ore gangue carbonates to establish: (1) timing
and duration, (2) redox evolution, and (3) flow rates of mineralizing fluids in the world-class San Vicente Zn-(Pb)
deposit (Peru). New radiometric ages bracket the crystallization of syn-mineralization dolomite, characterized by
high Fe and Mn contents and Sr isotopic values overlapping with that of host carbonates, between 103.2 ± 4.1
Ma and 70.6 ± 5.6 Ma. This age interval reveals a direct genetic relationship between flow of mineralizing fluids
and late Cretaceous Andean compressional tectonics. Basinal fluid expulsion coeval with known tectonic events
continues in the district until Pliocene times, driving episodic crystallization of post-ore hydrothermal carbonates
between 61.6 ± 9.3 and 2.7 ± 0.2 Ma. The low Mn and Fe content and high 87Sr/86Sr values characteristic of
these post-ore, bedding-parallel and cross-cutting carbonate veins indicate a colder, oxidized environment. Our
findings highlight the contribution of paired carbonate geochemistry and U-Pb geochronology in drawing links
between tectonic events, fluid expulsion and the waxing and waning of mineralization potential in foreland
basins. The results of this study challenge our understanding of timescales in MVT systems and imply that
anomalous metal enrichment in basinal fluids over a short temporal interval is not a necessary precondition to
form economic-sized, sediment-hosted Zn-Pb deposits. Rather, it is the coexistence of a focused fluid flow in an
interconnected aquifer with suitable metal depositional mechanisms over a prolonged period of time (10^6–10^7
yr) that allows precipitation of economic amount of base metals at a specific site in the upper crust.
... Minerals in the garnet group-which are found in the upper mantle, at different metamorphic temperatures, and in skarn deposits-are preferred for geochronological studies because they have high HREE contents [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Garnets growing under different physicochemical conditions show oscillatory chemical zoning in gross-andradite and grossalmandine solid solutions during the contact metamorphism and hydrothermal alteration of carbonate rocks. ...
... Skarn garnets feature oscillatory zoning due to the physicochemical conditions, liquid composition, and fugacity during crystallization [7,[29][30][31]. Jamtveit et al. [71] stated that oscillatory zonation in garnets occurs during the growth process due to thermal and chemical diffusion (especially the transport of fluids through the recurrent fractures in the hydrothermal system [12] and the multiple effects of the magmatic fluid [37]). ...
The Fe skarn and vein-type Cu mineralization types are common in the Eastern Taurus Mountains. This study aims to determine the U-Pb geochronology of garnets of varying sizes within the skarn zone developed at the quartz diorite-marble contact zone in Ayazpınar, Pertek District, Tunceli Province, Turkey. Additionally, this study aims to determine the age of the skarnization and the types of inclusion minerals in the garnets. Faulting and magma emplacement along the thrust plane caused mineralization in the Eastern Taurus Mountains, especially at the marble and quartz diorite contact zone between the cities of Elazıg and Tunceli. The greenish garnets found in the Ayazpınar deposit are characteristic of distal skarns, while red or brown Pertek garnets are observed in the proximal skarns. The garnets typically feature a core-rim texture. The cores of the garnet crystals are large, reddish in color, and have a high REE (Ce, Pr) content. Moreover, the cores have higher Fe and lower Al ratios, alongside higher La, Ce, and Pr contents, than the rims. We propose that the compositional differences between the rims and the cores reflect the transition from oxidized REE-and Fe3+-rich liquids to liquids with lower REE and Fe3+ contents, producing the differences in the garnet colors. Green garnets show lower REE contents than brown garnets with Fe-rich cores. The skarn under study includes the following successively formed zones: diorite → epidote skarn → garnet-magnetite → pyrite-garnet-magnetite → calcite carbonate. Diopside, magnetite, and hematite, including small grains, are surrounded or enveloped by garnets. The U-Pb age of the mineralization is 74.1 ± 5 Ma, indicating that the mineralization occurred concurrently with the intrusion settlement.
... Adularia is prevalent at the quartz-sulfide-calcite stage (Figure 4c). Given the lower temperature of adularia crystallization [44], in line with the low closure temperature of the 40 Ar/ 39 Ar system [45], adularia is a promising candidate for constraining the time of syn-/post-gold mineralization at Tietangdong. Consequently, the obtained date of 135.9 ± 1.5 Ma (Figure 6) may represent the age of gold mineralization in the Tietangdong breccia pipe. ...
... This discrepancy might be derived from the application of different radiometric dating systems and analytical methods. After accounting for their systematic and the decay constant uncertainties of 40 Ar/ 39 Ar (~2%, total relative uncertainty [45][46][47]) and U-Pb (~3%, total relative uncertainty [45][46][47]), the overlapping results around ca. 136 Ma are revealed. In summary, the spatial and temporal evidence strongly support a close genetic relationship between gold mineralization and the intrusive rocks at the Tietangdong breccia pipe. ...
... This discrepancy might be derived from the application of different radiometric dating systems and analytical methods. After accounting for their systematic and the decay constant uncertainties of 40 Ar/ 39 Ar (~2%, total relative uncertainty [45][46][47]) and U-Pb (~3%, total relative uncertainty [45][46][47]), the overlapping results around ca. 136 Ma are revealed. In summary, the spatial and temporal evidence strongly support a close genetic relationship between gold mineralization and the intrusive rocks at the Tietangdong breccia pipe. ...
Magmatic–hydrothermal breccia pipes are widespread in numerous major porphyry and epithermal gold deposits globally, representing significant repositories of metal resources and serving as potential indicators for exploration targeting. More than ten breccia pipes occur in the Central Taihangshan District (CTD) of the North China Craton. Some of these breccia pipes host gold mineralization and are proposed to be related to the adjacent lode gold mineralization. However, the lack of detailed geological constraints make this hypothesis ambiguous. To address this, the present study conducted comprehensive field observations, drill core logging, an in situ sulfur isotope analysis of pyrite, and the 40Ar/39Ar dating of adularia along a 1400 m section of the Tietangdong breccia pipe at Yixingzhai. Three distinct breccia facies were identified at Tietangdong, exhibiting variable proportions across the entire section, including a massive skarn breccia; polymictic, skarn matrix-supported breccia; and polymictic, intrusive rock cement chaotic breccia. Furthermore, adularia 40Ar/39Ar dating indicates a syn-/post-gold mineralization age of 136 ± 1.5 Ma, coinciding with the age of post-breccia felsite dike. The deepest sampled pyrite displays δ34S values of ~2.7‰, strongly indicating a magmatic–hydrothermal signature. These results, when combined with the geological, geochronological, and isotopic studies on the adjacent lode gold mineralization, further suggest a close genetic relationship between the breccia pipes and the lode Au mineralization, paving the way for their utilization as effective indicators for gold targeting within the CTD.
... However, multiple magmatic-hydrothermal events from 156 ± 3 Ma to 118 ± 5 Ma have been recognized in the region (Wang et al., 2008;Gao et al., 2010;Mao et al., 2010;Li et al., 2012b;Ren, 2012;Zhao et al., 2012). Considering the relatively lower closure temperature of mica (∼300 °C; Chiaradia et al., 2013), it is highly probable that post-ore hydrothermal activities may have resulted in isotopic resetting of mica during thermal events and deformation, thereby casting doubt on the geological implications of the 40 Ar-39 Ar geochronology. ...
The Xiaoqinling gold province, located in the Neoarchean−Paleoproterozoic uplifted footwalls of the Xiaoqinling metamorphic core complex (XMCC), is one of China’s largest gold producers; however, achieving a consensus regarding their metallogenic model remains elusive. Scheelite is an indicator mineral that commonly occurs in lode gold deposits worldwide used to recognize deposit types and understand hydrothermal evolution and the origin of features. Xenotime, monazite, and rutile are common hydrothermal minerals in association with lode gold deposits worldwide. Here, we provide textual, in situ U-Pb geochronology of xenotime, monazite, and rutile, and in situ elemental and Sr-Nd isotopic compositions of scheelite within different stages from the large Yangzhaiyu lode gold deposit, aiming to elucidate its genesis and, for the first time, establish a holistic correlation between the lode gold mineralization and the evolution of the XMCC. Notably low εNd(t) values (−30.7 to −23.7), high 87Sr/86Sr ratios (0.72659−0.75914), and distinct rare earth elements, Sr, Mo, and As contents of scheelite confirm a metamorphic crustal source. Xenotime U-Pb dating and pre-ore (Stage I) scheelite reveal that ore-barren metamorphic fluids at ca. 140 Ma were oxidized with low Bi contents and buffered by greenschist facies metamorphism when the XMCC initiated. Monazite and rutile U-Pb dating combined with ore-stage scheelite geochemistry indicate a compositional shift in the more reduced auriferous metamorphic fluids, which dominated during major gold deposition periods (stages II and III) from 130 Ma to 120 Ma, characterized by significantly depleted Na and increased Bi contents. This resulted from the prograde greenschist-to-amphibolite metamorphism at mid-lower crustal depths as the result of the XMCC isostatic doming and the lithospheric mantle thinning after 130 Ma. This study highlights the crucial role of metamorphic core complexes in governing the timing, locations, and resources of the lode gold metallogenic system.
... The sericite and inclusion 40 Ar-39 Ar ages from the Xiaoshan deposits are 156.1 ± 1.0 Ma (Tang, 2014) and 130.6 ± 2.6 Ma , respectively. However, argon can diffuse out of the crystalline lattice of commonly dated minerals at temperatures lower than those at which they were crystallized (e.g., ~300 • C for biotite and ~ 350 • C for muscovite: Harrison et al., 1985;Chiaradia et al., 2013;Oriolo et al., 2018). The homogenization temperature of fluid inclusions (~393 ℃, Li et al., 2018a;2020) suggests that the primary ore formation temperature surpasses the mica's closure temperature. ...
... The ~166 Ma P1 granite hosts quartz wolframite vein W ores with newly obtained Re-Os isochron age of ~155 Ma. Studies have shown that the single magmatic hydrothermal event is mostly limited within a couple of million years, maximally not exceeding 10 Ma (Chiaradia et al., 2013). The occurrence of quartz wolframite vein W orebodies elucidates that the quartz vein W mineralization age was later than the intrusion of P1 granite (Fang et al., 2018). ...
... However, some zircons also yield concordant U-Pb age of 237.7 ± 0.7 Ma (Fig. 5b), with Th/U ratios ranging from 0.494 to 0.978 (SupplementaryTable S1), suggesting the fine-grained granite may have experienced magmatic activity in the Triassic. Accurately determining the precise age of ore deposit formation is challenging, especially when distinctly associated minerals providing insights into the mineralization process are scarce (Zack et al., 2011;Chiaradia et al., 2013). Cassiterite, a prominent ore mineral found in tin deposits, typically displays elevated concentrations of U and relatively low levels of common Pb within its lattice. ...
... The closure temperature of the muscovite-lepidolite 40 Ar/ 39 Ar dating system is 350-400°C, which is similar to the temperature of potassic alteration (Richards and Mumin 2013). The 40 Ar/ 39 Ar plateau age usually represents the cooling time of the experimental mineral below a specific temperature in the deposit rather than the crystallization age of the mineral (Chiaradia et al. 2013). Therefore, the 40 Ar/ 39 Ar age can be considered as the cooling and potassic hydrothermal alteration age of pegmatites ( Figure 8a). ...
... In addition to Cu, they also contain economic Mo, Au, Pb and Zn, Ag, and other metals (Sillitoe, 2010;Lin et al., 2023a, b). The lifespan and precise timing of the ore-forming magmatic systems of giant porphyry deposits have been a controversial issue (Chiaradia et al., 2013) because of multiple magmatism and hydrothermal events and because of the low precision of many geochronology studies. Due to the multiple stages of igneous emplacement, hydrothermal mineralization, and alteration, the duration of magmatism and mineralization is suspected to have played a significant role in controlling the size of the deposits, with evidence that the longevity of a hydrothermal system is to some extent proportional to tonnage (Harris et al., 2008;Chiaradia and Caricchi, 2017;Chelle-Michou and Schaltegger, 2018;Chiaradia, 2020;Chelle-Michou and Rottier, 2021). ...
... Highprecision chemical abrasion-isotope dilution-thermal ionization mass spectrometry (CA-ID-TIMS) zircon U-Pb dating and isotope dilution-negative-thermal ionization mass spectrometry (ID-N-TIMS) Re-Os dating of molybdenite indicate that some large porphyry copper systems formed rapidly, in 266 k.y. or less (Li et al., 2017;Large et al., 2020;Zhao et al., 2021). This indicates that the highest-precision geochronology methods are precise enough to yield the age and duration of porphyry systems, which are the accumulation of several pulsed, short-lived events (Chiaradia et al., 2013;Large et al., 2020). ...
... Here, we use highprecision CA-ID-TIMS U-Pb zircon dating to decipher the chronology of different porphyry intrusions at Jiama. In addition, 40 Ar-39 Ar dating of hydrothermal biotite coexisting with molybdenite from a deep monzogranite porphyry and from shallow hornfels helps us constrain the timing of hydrothermal events of the Jiama porphyry Cu system (Chiaradia et al., 2013(Chiaradia et al., , 2014. Finally, the accurate lifespan of magmatic events at Jiama is deciphered with these geochronological results, which helps to understand the ore-forming process in giant porphyry copper systems. ...
Jiama is the largest porphyry-skarn ore system in the Gangdese metallogenic belt, Tibet. It is composed of porphyry Cu-Mo, Cu-polymetallic skarn, Cu-Pb-Zn manto, and distal vein Au orebodies with associated Ag, W, and Bi. However, the precise timing of the magmatism and hydrothermal events at Jiama remains obscure. Here, using high-precision chemical abrasion-isotope dilution-thermal ionization mass spectrometry (CA-ID-TIMS) U-Pb zircon dating of ore-bearing and post-ore intrusions, we accurately constrain the lifespan of magmatism and hydrothermal mineralization. Monzogranite porphyry dikes are cut by Cu-Mo vein mineralization in the deeper part of the system, indicating that they were emplaced pre-ore, and yield a crystallization age of 15.534 ± 0.007 Ma (mean square of weighted deviates [MSWD] = 0.99, n = 6). A granodiorite porphyry that cuts the monzogranite porphyry and hosts vein and disseminated chalcopyrite and molybdenite is considered synchronous with ore and yields a crystallization age of 15.368 ± 0.007 Ma (MSWD = 1.01, n = 5). These two phases of intrusions are cut by quartz-diorite porphyry bodies, which yield a crystallization age of 15.076 ± 0.006 Ma (MSWD = 0.13, n = 6) and contain weak, subeconomic Cu and almost no molybdenum mineralization. A post-ore barren quartz monzonite porphyry yields a crystallization age of 14.925 ± 0.006 Ma (MSWD = 1.12, n = 6). The lifespan of magmatism at Jiama is thus about 0.61 m.y. The difference with previous molybdenite Re-Os isochron ages from the porphyry (14.7 ± 0.3 Ma), hornfel (14.7 ± 0.4 Ma), and skarn (15.4 ± 0.2 Ma) suggests that high-precision chronology is required to decipher accurate timing of mineralization in porphyry systems such as Jiama. The 40Ar/39Ar ages of hydrothermal biotite coexisting with molybdenite in monzogranite porphyry and hornfels are 15.25 ± 0.17 Ma (MSWD = 1.6) and 15.25 ± 0.24 Ma (MSWD = 0.14), respectively, slightly younger than the granodiorite porphyry and older than weakly mineralized quartz diorite porphyry, which represents the time of the ore-forming hydrothermal event. Thus, Jiama is the product of pulsed magmatism during which a short-lived hydrothermal event formed the giant Cu polymetallic system.
... Younger Triassic dates have also been proposed based on the argon-argon ( 40 Ar/ 39 Ar) thermochronometer in adularia, which is associated with sulfide and sulfosalt deposits that occur throughout the central and eastern Anti-Atlas and is interpreted as being paragenetically late with respect to arsenide ores at Bou Azzer (Levresse, 2001). However, 40 Ar/ 39 Ar ages in adularia are readily thermally reset (see Chiaradia et al., 2013). To end with, preliminary evidence from rhenium-osmium (Re-Os) dates of molybdenite at Bou Azzer imply a major ore-forming event for Co-Ni-arsenide mineralization in the Late Devonian (Stein et al., 2021). ...
Cobalt arsenide deposits associated with Neoproterozoic serpentinite in Morocco represent the highest-grade cobalt resource worldwide. Yet, genetic models for their origin remain controversial. We report here mineralogical and geochemical evidence for arsenide-calcite mineralization at Bou Azzer to constrain the temporal framework and identify the geodynamic trigger for mineralization mechanisms. To this end, radiometric ages for ore minerals are paramount for understanding the origin of the Bou Azzer cobalt arsenide deposit. New safflorite (CoAs2) rhenium-osmium (Re-Os) ages are Late Devonian in age: 380.1 ± 0.9 and 373.4 ± 1.2 to 368.1 ± 5.0 million years ago (Ma) for coarse-grained and fine-grained safflorite, respectively. These dates overlap with the timing of break-up of the supercontinent Gondwana, and the building of an arch-and-basin geometry from northern Africa to Arabia. Our findings temporally and spatially contextualize previous knowledge of fluid chemistry and mineralization mechanisms involving a two-fluid mixing. Arsenide mineralization resulted from mixing of a methane-dominated fluid with highly saline basinal brines that leached Os ([187Os/188Os]initial = 0.120 ± 0.001), and by corollary cobalt, from Neoproterozoic serpentinite. Carbon and sulfur stable isotope data of ore-stage calcite and arsenides, respectively, show that hydrocarbons acted as the main reductant for mineralization. We speculate that the seawater-derived brines sank into the sedimentary basins adjacent to a carbonate platform with the Bou Azzer serpentinite in its basement in the Late Devonian. In the context of an enhanced geothermal gradient, such brines would have been involved in warm hydrothermal alteration of hydrocarbon source rocks of the local expression of the Kellwasser event in the geological record of present-day Morocco. This warm hydrothermal alteration of hydrocarbon source rocks may have taken place for coarse-grained safflorite mineralization (380.1 ± 0.9 Ma) shortly after ca. 382–381 Ma Lower Kellwasser horizons were deposited, or, for fine-grained safflorite mineralization (373.4 ± 1.2 to 368.1 ± 5.0 Ma) while the Upper Kellwasser horizons of present-day Morocco were being deposited.
