Abstract:The subduction of oceanic plates beneath continental lithosphere is responsible for continental growth and recycling of oceanic crust, promoting the formation of Cordilleran arcs. However, the processes that control the evolution of these Cordilleran orogenic belts, particularly during their early stages of formation, have not been fully investigated. Here we use a multi-proxy geochemical approach, based on zircon petrochronology and whole-rock analyses, to assess the early evolution of the Andes, one of the m… Show more
“…Figure 3 presents zircon petrogenetic indicators of the intrusive units plotted against U–Pb ages used in the subsequent discussions. It also includes previously reported data for intrusive rocks located north of the study area, representing the magmatic conditions prior to the Copiapó Batholith 27 .…”
Section: Resultsmentioning
confidence: 99%
“… Figure 3 Zircon petrogenetic indicators of the Copiapó Batholith. Magmatic Stage I data are from Jara et al 27 . Molybdenite (Mo) Re–Os 33 and biotite (Bt) 40 Ar/ 39 Ar age 34 are shown as constraints on the timing of mineralization in Candelaria.…”
Section: Resultsmentioning
confidence: 99%
“…At ca. 112–110 Ma, the AFS become active under a compressional setting coinciding with the eastward migration of the magmatic arc 21 , 24 , 26 , 27 . During this period of crustal thickening, several porphyry Cu-Mo ± Au deposits such as Andacollo, Dos Amigos and Pajonales were emplaced between 116 and 90 Ma, forming a discontinuous belt to the east of the IOCG and IOA deposits 21 – 23 .…”
Iron oxide-copper-gold (IOCG) deposits are a vital source of copper and critical elements for emerging clean technologies. Andean-type IOCG deposits form in continental arcs undergoing extension, and they have a temporal relationship with magmatism although they do not exhibit a close spatial relation with the causative intrusions. The processes required to form IOCG deposits and their potential connections to iron oxide–apatite (IOA)-type mineralization remain poorly constrained, as well as the characteristics of magmatism linked to both deposit types. Here we combine zircon U–Pb geochronology with zircon trace element geochemistry of intrusive rocks associated with the Candelaria deposit, one of the world’s largest IOCG deposits, to unravel distinctive signatures diagnostic of magmatic fertility. Our results reveal a marked transition in the geochemistry of intrusions in the Candelaria district, characterized by changes in the redox state, water content and temperature of magmas over time. The oldest magmatic stage (~ 128–125 Ma), prior to the formation of the Candelaria deposit, was characterized by zircon Eu/Eu* ratios of 0.20–0.42, and redox conditions of ΔFMQ − 0.4 to + 1.0. The earliest magmatic stage related to the formation of Fe-rich mineralization at Candelaria (118–115 Ma) exhibits low zircon Eu/Eu* ratios (0.09–0.18), low oxygen fugacity values (ΔFMQ ~− 1.8 to + 0.2) and relatively high crystallization temperatures. In contrast, the youngest stage at ~ 111–108 Ma shows higher zircon Eu/Eu* (~ 0.37–0.69), higher oxygen fugacity values (ΔFMQ ~ + 0.4 to + 1.3) and a decrease in crystallization temperatures, conditions that are favorable for the transport and precipitation of sulfur and chalcophile elements. We conclude that Candelaria was formed through two distinct ore-forming stages: the first associated with a reduced, high temperature, water-poor magma developed under a low tectonic stress, followed by a more oxidized, water-rich, and low temperature magmatic event related to a compressional regime. The first event led to Fe-rich and S-poor IOA-type mineralization, while the second event with geochemical signatures similar to those of porphyry copper systems, generated the Cu- and S-rich mineralization. This late stage overprinted preexisting IOA mineralization resulting in the formation of the giant Candelaria IOCG deposit.
“…Figure 3 presents zircon petrogenetic indicators of the intrusive units plotted against U–Pb ages used in the subsequent discussions. It also includes previously reported data for intrusive rocks located north of the study area, representing the magmatic conditions prior to the Copiapó Batholith 27 .…”
Section: Resultsmentioning
confidence: 99%
“… Figure 3 Zircon petrogenetic indicators of the Copiapó Batholith. Magmatic Stage I data are from Jara et al 27 . Molybdenite (Mo) Re–Os 33 and biotite (Bt) 40 Ar/ 39 Ar age 34 are shown as constraints on the timing of mineralization in Candelaria.…”
Section: Resultsmentioning
confidence: 99%
“…At ca. 112–110 Ma, the AFS become active under a compressional setting coinciding with the eastward migration of the magmatic arc 21 , 24 , 26 , 27 . During this period of crustal thickening, several porphyry Cu-Mo ± Au deposits such as Andacollo, Dos Amigos and Pajonales were emplaced between 116 and 90 Ma, forming a discontinuous belt to the east of the IOCG and IOA deposits 21 – 23 .…”
Iron oxide-copper-gold (IOCG) deposits are a vital source of copper and critical elements for emerging clean technologies. Andean-type IOCG deposits form in continental arcs undergoing extension, and they have a temporal relationship with magmatism although they do not exhibit a close spatial relation with the causative intrusions. The processes required to form IOCG deposits and their potential connections to iron oxide–apatite (IOA)-type mineralization remain poorly constrained, as well as the characteristics of magmatism linked to both deposit types. Here we combine zircon U–Pb geochronology with zircon trace element geochemistry of intrusive rocks associated with the Candelaria deposit, one of the world’s largest IOCG deposits, to unravel distinctive signatures diagnostic of magmatic fertility. Our results reveal a marked transition in the geochemistry of intrusions in the Candelaria district, characterized by changes in the redox state, water content and temperature of magmas over time. The oldest magmatic stage (~ 128–125 Ma), prior to the formation of the Candelaria deposit, was characterized by zircon Eu/Eu* ratios of 0.20–0.42, and redox conditions of ΔFMQ − 0.4 to + 1.0. The earliest magmatic stage related to the formation of Fe-rich mineralization at Candelaria (118–115 Ma) exhibits low zircon Eu/Eu* ratios (0.09–0.18), low oxygen fugacity values (ΔFMQ ~− 1.8 to + 0.2) and relatively high crystallization temperatures. In contrast, the youngest stage at ~ 111–108 Ma shows higher zircon Eu/Eu* (~ 0.37–0.69), higher oxygen fugacity values (ΔFMQ ~ + 0.4 to + 1.3) and a decrease in crystallization temperatures, conditions that are favorable for the transport and precipitation of sulfur and chalcophile elements. We conclude that Candelaria was formed through two distinct ore-forming stages: the first associated with a reduced, high temperature, water-poor magma developed under a low tectonic stress, followed by a more oxidized, water-rich, and low temperature magmatic event related to a compressional regime. The first event led to Fe-rich and S-poor IOA-type mineralization, while the second event with geochemical signatures similar to those of porphyry copper systems, generated the Cu- and S-rich mineralization. This late stage overprinted preexisting IOA mineralization resulting in the formation of the giant Candelaria IOCG deposit.
“…Zircon, a highly resistant mineral to weathering and abrasion, is commonly found in igneous rocks resistant to weathering and hydrothermal alteration, thus providing valuable insight into magmatic events recorded in eroded clastic sediments (e.g., Capaldi et al, 2022; Joaquín Jara et al, 2021). The DZs from the HQSL are overwhelmingly magmatic in origin and mainly reflect a sufficient mixing of the source rock ages in the southern Great Xing'an Range and Yanshan orogenic belts.…”
The provenance and aeolian–fluvial interaction are essential for understanding the formation and evolution of sandy land. However, the dune sediment source in the Horqin Sandy Land (HQSL), the largest semi‐stable sandy land in China, has been debated. Here, we collected 900 coarse (i.e., >63 μm) and 750 fine (i.e., <63 μm) detrital zircon (DZ) grains from surface sand in different spatial locations for U–Pb age analysis. The visual comparison largely shows remarkably similar zircon age characteristics throughout the HQSL, and the quantitative results of the inverse Monte Carlo modelling show the primary detrital contribution of the Central Asian orogenic belt (~50.5%–61.3%) to the HQSL. In contrast, the southeast of the HQSL is characterized by the absolute dominance of the North China Craton (~75.8%). The DZ age spectra in the western and northern HQSL are extremely similar but significantly different from the south, indicating the spatial heterogeneity of the HQSL. The DZ ages are largely unaffected by particle size sorting, except in the southeastern HQSL (e.g., the dramatically different detrital contribution of the North China Craton to the fine [52.4%] and coarse fractions [75.8%]). We argue that the aeolian–fluvial interaction and the resulting sedimentary sorting and recycling are responsible for the DZ age characteristics of the HQSL. We confirm that the DZ ages of the HQSL are a faithful record of the tectonic‐magmatic events, for example, the North China Craton massif collision and collusion, the Paleo‐Asian Ocean subduction and closure, the Mongolian‐Okhotsk Ocean plate subduction and the paleo‐Pacific Ocean subduction and retreat. Finally, this study suggests that caution must be exercised in interpreting the paleoclimatic record and the aeolian deposit source investigations due to the spatial heterogeneity and the complex wind‐fluvial interactions in the HQSL.
“…The Eastern Cordillera (EC), a young orogen (Cordilleran orogenic belts), separates the Orinoquia and Amazon basins from the Colombian Andean Block (CAB) continental growth by multiple accretion reaching [37], intracontinental [38] and wide plate margin deformation [39], and magmatism evolved in response to changes in the tectonic configuration [40,41], from transtensional/extensional conditions (215-145 Ma) to a transtensional regime (138-94 Ma), according to [40].…”
Section: A Colombian Andean Cordillera: Geological Framework and Phys...mentioning
This article presents a comprehensive vision of particularities and constraints of the Paja Formation in the Northern Andes of Colombia, supported by personal, institutional, and academic experiences, including a doctoral thesis in completion (geomorphology and risks research line). Such fine-grained marine rocks cause severe damage in diverse zones, with little spread, and are very unfavorable, especially within the Eastern Cordillera (departments of Santander and Cundinamarca), whose socio-environmental problems motivated a popular legal action in the municipality of Vélez due to the cracking and collapse of houses, damage to roads and landslides in the urban area, as well as flows, subsidence, and high hydrogeochemical dynamism or rare earths, although they also presented spontaneous ignition at the rural area. Understanding how these problems originate and interrelate is the main objective of the work. At the beginning, we include some brief definitions, terms, and key approaches to understand the consolidated geomaterials, location, and background of the problem; then, the results of meso–macro–micro studies, obtained by combining the field techniques and conventional instrumental laboratory analyses (tests on the chemistry of water and soil, description of samples with magnifying glasses, petrography with a polarized light microscope, micromorphology of regoliths–colluvions) of nanoscientists (emphasizing RXD-RXF, SEM, IR-Raman spectroscopy, TOC-TS) are presented. These characterizations and new knowledge must be socially and institutionally appropriated and applied in land use planning and risk management for the sustainability of challenging environments with the stratiforms of Lower Cretaceous rocks and associated Quaternary deposits in populated mountainous areas and contrasting intertropical hydroclimatological regimes, geologically active, so unstable and insecure.
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