Precambrian Research最新文献

{"title":"Late Paleoproterozoic within-plate mafic magmatism in the western Yangtze Block, South China Craton: Implications for the initial break-up of the Columbia supercontinent","authors":"Luyu Huang ,&nbsp;Jing Zhao ,&nbsp;Youliang Chen ,&nbsp;Xiaoping Long ,&nbsp;Jingsi Zhang ,&nbsp;Qiaoping Guo","doi":"10.1016/j.precamres.2024.107609","DOIUrl":"10.1016/j.precamres.2024.107609","url":null,"abstract":"<div><div>The Paleoproterozoic was an important period for the tectonic-magmatism evolution of the Yangtze Block, which coincided with the assembly and break-up of the global Columbia (also known as Nuna) supercontinent. However, an essential issue, when the Yangtze Block initiated rifting from the supercontinent, remains controversial. This paper presents new zircon chronology, Lu-Hf isotopic data, and whole-rock geochemical analyses of the Bajiaojing and Xiaoqingshan meta-diabases in the western Yangtze Block to address this issue. The magmatic zircons from the Bajiaojing and Xiaoqingshan meta-diabases yielded U-Pb ages of 1675 ± 38 Ma and 1719 ± 10 Ma, representing an episode of mafic magmatism during the Late Paleoproterozoic. Moreover, the abundances and elemental ratios of high-field-strength elements (HFSEs, e.g., Y, Ta, Th, and Hf) in both meta-diabases are very similar to those of within-plate and mantle plume magmas. This implies that these Late Paleoproterozoic mafic rocks were likely derived from a mantle plume source in a continental within-plate extensional setting. Their magmatic source was relatively heterogeneous in isotopic and geochemical compositions, as inferred from significant differences in ε_Hf(t) values and certain HFSE ratios (e.g., Nb/Yb, Ta/Yb, Th/Yb, Nb/Y, and Zr/Y) among samples. Such source heterogeneity might be attributed to interactions between the mantle plume and the overlying lithosphere. Combined with published ε_Hf(t) values of detrital zircons and whole-rock ε_Nd(t) values of (meta-)magmatic rocks, we speculate that the Yangtze Block experienced a tectonic transition from plate convergence to continental extension at ∼ 1.7 Ga. This means that the block began to rift from the Columbia supercontinent as early as 1.7 Ga. The Yangtze Block then evolved progressively as an isolated fragment until it was amalgamated into the Rodinia supercontinent.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107609"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sapphirine + quartz assemblage from the Irumide Belt, northern Malawi: Implications for Mesoproterozoic ultrahigh-temperature metamorphism related to Rodinia assembly","authors":"So Wakabayashi ,&nbsp;Kabang’u Grace Sakuwaha ,&nbsp;Toshiaki Tsunogae ,&nbsp;M. Santosh ,&nbsp;Mzee Wandembo Nyirongo","doi":"10.1016/j.precamres.2024.107607","DOIUrl":"10.1016/j.precamres.2024.107607","url":null,"abstract":"<div><div>The Irumide Belt <em>sensu lato</em> situated between the Bangweulu Block to the northwest and the Neoproterozoic Mozambique–Zambezi Belt to the southeast is a Mesoproterozoic orogenic belt that developed probably during the amalgamation of the supercontinent Rodinia. In this study, we present new petrological, geothermobarometric, and geochronological data of pelitic granulites and related rocks from the Jenda area in northern Malawi, and evaluate the timing and pressure–temperature (<em>P</em>–<em>T</em>) conditions of high-grade metamorphism. To the best of our knowledge, we are the first to report the occurrence of sapphirine + quartz association in pelitic granulite from the Irumide Belt <em>sl</em>. which provides a robust evidence of peak ultrahigh-temperature (UHT) metamorphism. The sapphirine occurs as poikiloblastic grains with rounded quartz inclusions in the absence of any retrograde minerals. The mineral phase equilibrium modeling constrains the peak UHT conditions of the pelitic granulites as 950–1000 °C and 7–8.5 kbar for sapphirine-bearing and ∼6 kbar and &gt; 950 °C for sapphirine-free samples. These conditions are consistent with the results of ternary-feldspar geothermometry (900–1000 °C at 8 kbar). From the stability of rutile, we estimate a prograde pressure of &gt;9 kbar, and the occurrence of retrograde cordierite and biotite suggests that the rocks went through <em>P</em>–<em>T</em> conditions of ∼6–7 kbar/∼775–825 °C, indicating a clockwise <em>P</em>–<em>T</em> path and defining high-pressure and UHT conditions. In-situ monazite Th–U–Pb_total geochronology of the sapphirine-bearing rock yielded a weighted-mean age of 1022 ± 10 Ma which is considered to mark the timing of peak metamorphism. Sapphirine-free granulites also gave consistent ages of 1049 ± 13 Ma and 1048 ± 10 Ma, which are also comparable with published ages. We thus infer that the Irumide Belt <em>sl</em>. underwent regional high-pressure to UHT metamorphism at ca. 1.05 to 1.02 Ga possibly related to the main collisional event of the Bangweulu Block with an unknown craton or magmatic arc during the assembly of Rodinia supercontinent.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107607"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Precambrian Earth: Co-evolution of life and geodynamics","authors":"Frances Westall ,&nbsp;Shuhai Xiao","doi":"10.1016/j.precamres.2024.107589","DOIUrl":"10.1016/j.precamres.2024.107589","url":null,"abstract":"<div><div>The Precambrian covers 80% of the history the Earth. In this timespan, the Earth developed from an anaerobic planet to the oxygenic planet dominated by Wilson-style plate tectonics that we know today. Concomitant with geological evolution, life emerged and evolved, gradually colonising all known aqueous habitats. Until the Palaeoarchaean, life was largely dominated by its geological environment. However, as of the Mesoarchaean, when there were major changes in geodynamics leading to continental erosion and runoff of essential nutrients, the effects of life started to impinge on the geological environment. The interaction of life and Earth was and is reciprocal, hence the term biogeodynamics. In this review, we trace the evolution of geology and life in parallel, thus highlighting the gradual buildup of the importance of life on terrestrial processes, and the importance of changes in the geological environment on the evolution of life. We do not attempt to make an exhaustive review of all the occurrences of life in the Precambrian but use selected examples to illustrate key events and changes. We conclude by addressing certain aspects of the evolution of life that require more in-depth study and show how the finding of extra-terrestrial life would advance our understanding of life on Earth.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107589"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Widespread ca. 800 Ma granitoids in the southern Dabie Orogen: Petrogenesis and implications for Neoproterozoic accretion-type orogeny in the northern Yangtze Block","authors":"Chao Chen ,&nbsp;Zhenbing She ,&nbsp;Changqian Ma ,&nbsp;Jinling Yuan ,&nbsp;Lingyao Kong ,&nbsp;Di Wang ,&nbsp;Jiang Zhu ,&nbsp;Chuan Fan ,&nbsp;Pan Guo ,&nbsp;Hao Deng ,&nbsp;Roger Mason","doi":"10.1016/j.precamres.2024.107610","DOIUrl":"10.1016/j.precamres.2024.107610","url":null,"abstract":"<div><div>Large-scale Neoproterozoic granitoids occur widely in the Dabie Orogen of the northern Yangtze Block and provide significant clues to understanding the geological evolution of the Block within the Rodinia supercontinent. We present evidence for a prominent episode of granitoid intrusion at ca. 800 Ma in the southern Dabie Orogen (SDO), verified by new zircon LA-ICP-MS ages from four separate granitoid intrusions ranging from 807 Ma to 795 Ma in age. The granitoids are dominated by monzogranite and granodiorite with bulk-rock A/CNK and zircon <em>δ</em>¹⁸O values of 0.90–1.10 and 5.03–6.45‰, respectively, corresponding to I-type affinity. This is also supported by negative correlations of SiO₂ vs. P₂O₅ and Sr vs. P₂O<strong>₅</strong>, and positive correlations of SiO₂ vs. A/CNK, Rb vs. Y and Rb vs. Th. Low zircon ε_Hf(t) values (−15.03 to −3.84) and relatively old two-stage Hf model ages (mainly between 1900 and 2200 Ma) for these granitoids are consistent with primary derivation of magma from partial melting of Paleoproterozoic metabasites. Relatively low Ga/Al ratios, Zr contents, and zircon saturation temperatures and consistently negative zircon ε_Hf(t) and bulk-rock ε_Nd(t) values are distinct from those of 780–720 Ma A-type granites in the Dabie Orogen that formed in a rift setting. We propose that the ca. 800 Ma granitoids in the SDO were products of variable degrees of partial melting of ancient mafic crust, promoted by heating of the upwelled asthenosphere due to oceanic slab breakoff in an accretion-type orogeny. Our observations suggest that the formation of the unified Yangtze Block was achieved by diachronous assembly of multiple micro-blocks during the Neoproterozoic, consistent with a peripheral location of the Yangtze Block in the Rodinia supercontinent.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107610"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Syn-rift volcanism (ca. 670 Ma) in the lower Windermere Supergroup, southern Canadian Cordillera: New constraints on the syn- to post-rift transition for northwestern Laurentia","authors":"Thomas Hadlari ,&nbsp;N.M. Rayner ,&nbsp;T.P. Poulton ,&nbsp;R.W.C. Arnott","doi":"10.1016/j.precamres.2024.107604","DOIUrl":"10.1016/j.precamres.2024.107604","url":null,"abstract":"<div><div>The southern Canadian Cordillera is considered the type area for the Windermere Supergroup, where it had long been assumed that the <em>syn</em>-rift basaltic lavas of the Irene Formation were co-genetic with the ca. 720 Ma Franklin LIP. Accordingly, the inferred age of the Irene volcanics is variously cited for either the breakup of Rodinia or for the base of Cryogenian strata in the southern Canadian Cordillera, and yet they have not been directly dated until now. Reported here are geochronological data from a volcanic sample of the Irene Formation yielding a U-Pb SHRIMP zircon age of 669.6 ± 6.7 Ma, which is significantly younger than the presumptive age. The Irene Formation is overlain by basin floor turbidite facies that correlate with the Horsethief Creek Group, which represent some of the oldest post-rift deposits in the study area and are interpreted as the earliest indication of a passive continental margin setting for northwestern Laurentia. The dated sample was collected from the upper portion of the Irene Formation and so the transition from <em>syn</em>-rift to post-rift is younger than ca. 670 Ma, which is estimated at approximately 660–650 Ma. Additionally, these new age data place the associated diamictites at the end of the Sturtian glaciation.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107604"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The early syn-tectonic mafic to felsic Oamikaub Ring Complex (Damara orogen, Namibia) revisited – No role for a Pacific-type subduction?","authors":"S. Jung,&nbsp;R.L. Romer","doi":"10.1016/j.precamres.2024.107612","DOIUrl":"10.1016/j.precamres.2024.107612","url":null,"abstract":"<div><div>The Damara orogen of Namibia is an essentially ensialic orogen that was formed in the Neoproterozoic between ∼ 750 and ∼ 450 Ma. Most igneous rocks have negative εNd values and radiogenic Pb isotope compositions reflecting their crustal provenance. Mafic rocks are rare. The ∼ 564 Ma-old Oamikaub Ring Complex as part of the Goas Intrusive Suite belongs to a suite of mafic (ultramafic) to intermediate rocks that mark the onset of collision tectonics in the Damara Belt of Namibia. Therefore, they are particularly suitable to constrain the contribution of mantle material during the early stages of the Damara orogeny. The Oamikaub Ring Complex contains gabbros, gabbro-diorites, diorites, granodiorites and granites. All gabbros, gabbro-diorites and diorites are moderately enriched in most incompatible elements including REE but depleted in Rb, Ba and Sr. HFSE are depleted relative to primitive mantle (Zr/Hf: 28.3–40.5, Nb/Ta: 7.88–19.2) as a result of accumulation processes and the presence of enriched interstitial melts. The Sr and Nd isotopic compositions are variable (initial ⁸⁷Sr/⁸⁶Sr: 0.7058 to 0.7095; initial εNd: −1.9 to −11.8). The granodiorites are also enriched in incompatible elements showing similar HFSE abundances as the gabbros, gabbro-diorites, and diorites (Zr/Hf: 29.4–37.3; Nb/Ta: 8.25–19.7) and more evolved initial ⁸⁷Sr/⁸⁶Sr (0.7078 to 0.7103) and initial εNd (−10.7 to −14.1). Granites show lower Zr/Hf (18.7–28.7) but broadly similar Nb/Ta (4.25–14.6). Strontium and Nd isotopes are distinct relative to the other rock types (initial εNd: −18.2 to −18.8; initial ⁸⁷Sr/⁸⁶Sr: 0.7117–0.7128) implying an ancient lower crustal source. There are two competing models for the Damara orogen; a “Pacific-type” model involving subduction of oceanic crust and an ensialic model with subduction of mainly extended continental crust. Our new data from the Oamikaub Ring Complex, especially from the gabbros, gabbro-diorites and diorites, lack depleted isotope signatures but bear a strong crustal flavour for all rock types making a common subduction zone environment involving the subduction of oceanic crust unlikely. The rocks of the Oamikaub Ring Complex have isotope signatures similar to “lower crust” that are explained by “flat” subduction involving ancient continental mantle lithosphere and continental crust without melting of depleted asthenospheric mantle.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107612"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Rio de la Plata and Paranapanema cratons: Uncovering the hidden pieces of west Gondwana","authors":"Miguel A.S. Basei ,&nbsp;Mathias Hueck ,&nbsp;Sebastián Oriolo ,&nbsp;Mario C. Campos Neto","doi":"10.1016/j.precamres.2024.107582","DOIUrl":"10.1016/j.precamres.2024.107582","url":null,"abstract":"<div><div>The Rio de la Plata and Paranapanema cratons are major constituents of the South American Platform, yet both cratons are predominantly covered by Paleo- to Cenozoic basins. Because of that, much about their geological evolution and tectonic position in different supercontinent cycles is still little known, and most inferences about these paleocontinents is recorded indirectly in their surrounding orogenic systems. This special volume collects 15 novel contributions highlighting recent advancements in uncovering the cratonic blocks and their surrounding orogenic systems, from their ancient evolution to their tectonic significance during the assembly of Gondwana and establishment of the Proto-Pacific active margin. The collected studies span a large geographic extent in South America and African counterparts, and follow a variety of methodological approaches.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107582"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deformation in the Agnew-Wiluna Greenstone Belt and host Kalgoorlie Terrane during the c. 2675–2630 Ma Kalgoorlie Orogeny: ∼45 Ma of horizontal shortening in a Neoarchean back-arc region","authors":"Quentin Masurel,&nbsp;Nicolas Thébaud","doi":"10.1016/j.precamres.2024.107586","DOIUrl":"10.1016/j.precamres.2024.107586","url":null,"abstract":"<div><div>This study re-evaluates the tectonic processes that contributed to the final assembly of the Yilgarn Craton (Western Australia) in the late Neoarchean. We combine regional-scale (10–100 km) geological data collected from surface exposures over the Agnew-Wiluna Greenstone Belt (AWGB) in the Kalgoorlie Terrane of the Eastern Goldfields Superterrane (EGST) together with published and open-file geochronological and structural data from the Geological Survey of Western Australia. The combined datasets are then compared with the structural record in the Kalgoorlie Terrane, allowing for new insights into the tectonic evolution of the EGST and broader Yilgarn Craton. We show that c. 2675–2630 Ma orogenic deformation in the AWGB was associated with a protracted sequence of events, marked by the activation of distinct shear zones through time and repeated shifts in the location of sedimentary depocentres. We propose that the observed strain pattern resulted from the complex interplay of deformation, magmatism, and sediment deposition under progressive, ENE-WSW-directed horizontal shortening spanning ∼45 Ma. We suggest that the identified deformation scheme represents the local expression of tectono-thermal events affecting the Kalgoorlie-Kurnalpi Rift and broader EGST. Building on prior knowledge on the geological evolution of the Yilgarn Craton, our study supports a model proposed more than a decade ago whereby orogenesis was driven by a west-dipping, outboard subduction zone located further east of the exposed margins of the Yilgarn Craton. Lastly, we emphasize that such scale-integrated, unified perspective provides a balanced reconciliation between the debated allochthonous and <em>para</em>-autochthonous models for the EGST.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107586"},"PeriodicalIF":3.2,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Linking Neoproterozoic lode gold provinces to a metasomatized mantle source in South China: Evidence from fluid inclusions and H-O-S-Pb isotope systematics","authors":"Huimin Wang ,&nbsp;Qinglin Xia ,&nbsp;Liang Cao ,&nbsp;Yin Gong ,&nbsp;Zhou Zhou ,&nbsp;Li Lei ,&nbsp;Yongpu Wu ,&nbsp;Changliang Chen","doi":"10.1016/j.precamres.2024.107603","DOIUrl":"10.1016/j.precamres.2024.107603","url":null,"abstract":"<div><div>Lode gold deposits are typically formed in fields, belts, or provinces, representing the peak stages of continental crust growth and spanning from the Archean to the Neogene. The Meso- and Neoproterozoic eras represent critical stages of the continental crust growth period. In fact, the formation of lode gold deposits during this period has attracted considerable attention due to their global rarity. Recently, a Neoproterozoic lode gold province, encompassing more than 70 gold deposits/occurrences with over 300 gold veins, has been identified in the Huangling area of South China. Nevertheless, our understanding of the fluid characteristics, source, and evolution governing the formation of Neoproterozoic lode gold provinces remains relatively poor. To address these issues, pyrite-chalcopyrite-gold-dominated quartz veins from four representative deposit areas (Guaizigou, Mahuagou, Hongwucun, and Shuiyuesi) under various rock formations were studied through fluid inclusion and H-O-S-Pb isotope assessments. These fluids exhibited medium–low temperature, medium–low salinity, and an H₂O-NaCl-CO₂ ± CH₄ system. The calculated <em>δ</em>¹⁸O_water and δ¹⁸D_water values of quartz in the ore-forming fluids ranged from −1.7 to + 3.6 ‰ and −74.1 to −40.5 ‰, respectively, suggesting that the ore-forming fluids were derived from a combination of mantle sources, metamorphic water, and meteoric water. The influence of the mantle-derived fluids on the southern gold deposits was significant. Fluids in sulfur isotope equilibrium with pyrite exhibited δ³⁴S_H2S values between + 3.1 and + 6.7 ‰, which is consistent with a mantle origin under crustal influences. The Pb isotopes of pyrite indicated a metasomatized lithospheric mantle origin of the gold deposits in the region, which is similar to local mafic dikes. In addition, the gold deposits are strengthened by crustal contamination progressing from south to north of the Huangling area. According to previous Sr-Nd-C isotope data and multiple isotopic features, the ore-forming fluids and metals were derived from a metasomatized lithospheric mantle in the Neoproterozoic lode gold provinces of South China. The gold deposits interacted with basement rocks through their movement path and ore-forming fluid ascendancy. The fluids might be boiled due to rapid cooling and decompression. Indeed, they experienced mixing with a small amount of meteoric water and ultimately precipitated at secondary faults, leading to gold mineralization.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107603"},"PeriodicalIF":3.2,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrogenesis and tectonic setting of mafic magmatism within the Laguna Amarga Metamorphic Complex, Andes of Catamarca, Argentina: Insights into the opening of the Cuyania/Precordillera terrane from the Ouachita rift","authors":"Eber A. Cristofolini ,&nbsp;Facundo A. Escribano ,&nbsp;Juan E. Otamendi ,&nbsp;Augusto F. Morosini ,&nbsp;Andrea C. Galli ,&nbsp;Paula Armas ,&nbsp;María Paula Benito ,&nbsp;Matías G. Barzola","doi":"10.1016/j.precamres.2024.107601","DOIUrl":"10.1016/j.precamres.2024.107601","url":null,"abstract":"<div><div>Neoproterozoic crystalline basement rocks are exposed as fault-bounded blocks over the high Andes of Catamarca. The crystalline basement is stratigraphically grouped into the unique Laguna Amarga Metamorphic Complex and represents the northern extension of the Cuyania/Precordillera terrane. Tabular bodies of <em>meta</em>-mafic rocks are widespread in the basement interspersed within a thick sequence of <em>meta</em>-sedimentary rocks derived from siliciclastic, calc-silicate, and limestone protoliths. Overall, the geochemical characteristics of <em>meta</em>-mafic rocks are in the compositional range of Normal-Mid Ocean Ridge Basalt (Normal-MORB), reflecting a common depleted-mantle source with varying degrees of partial melting. While preserving the typical bulk chemistry of MORB magmatism, some mafic magma underwent differentiation at emplacement, leading to the development of high-Ti mafic rocks. New U-Pb zircon geochronology reveals three distinct age peaks, with two coinciding with ages identified in the metasedimentary host rocks. The dominant Mesoproterozoic age cluster is linked to inherited zircon crystals assimilated within a single <em>meta</em>-mafic rock. In contrast, zircon ages from the late Ordovician to early Devonian are attributed to metamorphic overgrowths. Notably, the third age cluster, delineates a Late Neoproterozoic magmatic event, indicating the temporal span of mafic magmatism. The finding agrees with the best available age (576 ± 17 Ma) for mafic magmatism on the Precordillera Mafic-Ultramafic Belt. Stratigraphic relationships and geochemical fingerprints enable correlation among the <em>meta</em>-mafic rocks from Laguna Amarga, tracing a belt of mafic magmatism with an oceanic affinity that extends southward. Building upon previous works, this study reaffirms that the rift-drift transition of the Cuyania/Precordillera terrane, linked to the Ouachita rift opening from southeastern Grenville, evolved during the latest Neoproterozoic.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107601"},"PeriodicalIF":3.2,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}