Lithos最新文献

{"title":"Isothermal compression record in the high-pressure Bantimala garnet amphibolite: Implications on the Mesozoic subduction system between the Sundaland and Western Sulawesi (Indonesia)","authors":"Juiyen Hsia ,&nbsp;Jian Zhang ,&nbsp;Jiahui Qian ,&nbsp;Jin Liu ,&nbsp;Minjie Guo ,&nbsp;Chenying Yu ,&nbsp;Welson Weisheng Xian ,&nbsp;Changqing Yin ,&nbsp;Yuntao Tian","doi":"10.1016/j.lithos.2024.107813","DOIUrl":"10.1016/j.lithos.2024.107813","url":null,"abstract":"<div><div>The isothermal compression is a special prograde metamorphic P-T path in high-pressure rocks. However, the exact geodynamic processes and associated tectonic significance of this path remain unclear. The Mesozoic subduction and collision between the Sundaland Block and east Java-west Sulawesi (EJWS) generated various metamorphic rock assemblages, thus leading to the crucial need to understand the evolution of the Meso-Tethys. The Bantimala Complex is a key metamorphic basement in Western Sulawesi that preserves records of high-pressure (HP) to ultrahigh-pressure (UHP) metamorphism during Cretaceous subduction. This manuscript presents a detailed petrological, mineralogical, geochronological, phase equilibrium modelling, and Zr-in-rutile thermometry study of a garnet amphibolite from the Bantimala Complex. Petrographic observations indicate that the garnet amphibolite underwent three metamorphic stages that include prograde (M₁), peak (M₂), and retrograde (M_3a and M_3b) stages. Pseudosection modelling constrains the P-T conditions of these stages at 13–15.5 kbar/565–585 °C (M₁), ∼23.5 kbar/588 °C (M₂), 8–9.5 kbar/410–480 °C (M_3a), and 8.3–8.8 kbar/415–440 °C <em>(</em>M_3b), respectively. U<img>Pb dating utilizing magmatic zircon reveals a protolith formation age of 212 ± 3.1 Ma. ⁴⁰Ar/³⁹Ar dating results from sodic-calcic amphibole and phengite indicate the timing of HP metamorphism at 136–128 Ma (Early Cretaceous). In contrast to other HP metamorphic rocks in the Bantimala Complex (eclogite and blueschist), garnet amphibolite exhibits a unique counterclockwise P-T path that includes an isothermal compression stage. This implies that the rock likely detached from the upper plate and was transported to the lower plate within the subduction zone. Following peak metamorphism at a depth of approximately 75 km, it was exhumed along with other HP metamorphic rocks to a shallower crustal depth of approximately 25 km. Combined with the available data, this study also reveals the coexistence of diverse P-T trajectories within the Bantimala Complex, thus providing robust evidence for a Mesozoic subduction system between the Sundaland Block and Western Sulawesi (Indonesia).</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"488 ","pages":"Article 107813"},"PeriodicalIF":2.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312923","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":"Final subduction-closure process of the Paleo-Asian Ocean in the middle segments of the southern Central Asian Orogenic Belt: Constraints from Permian volcanic rocks and late Triassic mafic dike swarms","authors":"Rongsong Tian ,&nbsp;Zhangqing Yan ,&nbsp;Guoai Xie","doi":"10.1016/j.lithos.2024.107805","DOIUrl":"10.1016/j.lithos.2024.107805","url":null,"abstract":"<div><p>The final subduction-closure process of the Paleo-Asian Ocean (PAO) in the middle segments of the southern Central Asian Orogenic Belt (CAOB) is widely debated. Linear arc-related pyroclastic sedimentary rocks and subsequent mafic-alkaline intrusive rocks parallel to the orogenic belt provide valuable constraints on ocean closure. Linearly distributed volcanic samples from the northern margin of the Alxa Block have zircon U<img>Pb ages ranging from 272 to 271 Ma, displaying arc geochemical signatures and large ranges of variation (−14.4 to +6.4) of zircon Hf isotopic composition. The Honggueryulin mafic dikes in the Nuoergong–Langshan Belt (NLB) with zircon and apatite U<img>Pb dating of 232–231 Ma show a clear geochemical imprint of subduction components with enrichment of light rare earth elements and large-ion lithophile elements (e.g., K, Rb, and Ba) and depletion of high-field-strength elements (e.g., Nb, Ta). The whole-rock major and trace elements and Sr–Nd–Hf isotopic compositions suggest that the Late Triassic mafic dikes mainly originated from a lithospheric mantle that had been metasomatized by subduction-related fluids. Coupled with published data, our geochronological and geochemical data support an east–west-trending Late Triassic alkaline–mafic intrusive rock belt distributed along the northern margin of the Alxa Block–North China Craton, which was formed in a post-orogenic intraplate extensional setting. These pyroclastic sediments and mafic dikes in the NLB document the tectonic transition from the Permian subduction to the Late Triassic post-orogenic extension. Therefore, the final closure of the PAO in the middle segments of the southern CAOB is constrained to between the Early and Middle Triassic.</p></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"488 ","pages":"Article 107805"},"PeriodicalIF":2.9,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142241390","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":"Tectonic affinity and evolution of the Foziling Group: A window into the Dabie orogenic belt's shallow subduction process","authors":"Jiankang Tang ,&nbsp;Yonghong Shi ,&nbsp;Nanfei Cheng ,&nbsp;Genshan Yang ,&nbsp;Junjie Li ,&nbsp;Guoxing Tang","doi":"10.1016/j.lithos.2024.107804","DOIUrl":"10.1016/j.lithos.2024.107804","url":null,"abstract":"<div><p>The Dabie orogenic belt (DOB) has been a classical hot spot for the study of deep continental subduction. However, research on the characteristics of the shallow subduction of the belt is lacking, which limits the full interpretation of the subduction and exhumation processes in the DOB. The Foziling Group, located at the northernmost edge of the DOB, has been considered the best carrier for studying the shallow subduction. Unfortunately, there has been a considerable amount of controversy regarding the metamorphic grade and tectonic affinity of the Foziling Group. For this reason, detailed studies involving geological surveys, petrography, mineral chemistry, geothermobarometry, and detrital zircon geochronology were conducted on the group. The Foziling Group is mainly composed of mica schist, garnet-mica schist, mica-quartz schist, and a small amount of quartzite and marble. Based on the evaluation of the peak metamorphic <em>P-T</em> conditions for 45 samples and previously reported six peak metamorphic <em>P-T</em> values, the Foziling Group can be divided into Zone I and Zone II, whose peak metamorphic conditions are <em>T</em> = 467–519 °C and <em>P</em> = 0.39–0.57 GPa and <em>T</em> = 535–645 °C and <em>P</em> = 0.59–0.96 GPa, respectively. Both <em>P-T</em> estimates fall within the amphibolite facies, and a ∼ 26 °C/km geothermal gradient line was constructed in the field, indicating that the Foziling Group experienced Barrovian metamorphism. Moreover, U<img>Pb dating of 465 detrital zircon grains from 5 samples of the group revealed five age peaks at 2.48, 0.94, 0.82, 0.63, and 0.44 Ga and two sub-peaks around ∼2.0–1.85 and ∼ 1.4 Ga. Among them, the youngest six detrital zircon ages range from 412 ± 12 Ma to 389 ± 14 Ma, which indicates that the Foziling Group formed during the Late Devonian. Combining the provenance analysis of detrital zircons, all zircons from the Foziling Group are derived from the DOB, suggesting that the Foziling Group belongs to the Yangtze Block. Compared with the peak metamorphic conditions, the timing of protolith formation, and the ∼ 17 °C/km geothermal gradient line of the Susong Complex at the southern margin of the DOB, both units are interpreted as Late Paleozoic passive continental margin sediments at the northern edge of the Yangtze Block, having both experienced shallow crustal-level subduction during the Indosinian period of the Dabie orogeny. This subduction was of the warm type, terminating near the Moho discontinuity. In contrast, the deep continental subduction of the belt reached the lithospheric mantle and asthenospheric depths, representing a cold subduction type. The transition between these subduction types is speculated to be due to the change in the subduction angle of the tectonic plate.</p></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"488 ","pages":"Article 107804"},"PeriodicalIF":2.9,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142241391","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":"Zircon U-Pb-Hf isotopes constraints on the petrogenesis of Neoarchean granitic rocks from the Northeastern part of the Eastern Dharwar Craton, Southern India","authors":"B. Vikram Raju ,&nbsp;Ajay Dev Asokan ,&nbsp;Xiao-Ping Xia ,&nbsp;Zexian Cui ,&nbsp;Arathi G. Panicker ,&nbsp;M. Ram Mohan","doi":"10.1016/j.lithos.2024.107807","DOIUrl":"10.1016/j.lithos.2024.107807","url":null,"abstract":"<div><div>In the present study, we integrate bulk rock chemistry and in-situ zircon U-Pb-Hf isotopes of high-K Neoarchean granitoids from the northeastern part of the Eastern Dharwar Craton (EDC) to investigate their source, petrogenesis, and plausible tectonic setting. Based on the mineral assemblage, in coherence with their geochemical characteristics, these granitoids are classified as Hornblende-biotite granite (HBG) with Microgranular enclaves (ME), Biotite granite (BTG) and Monzogranite (MG). Field observations and zircon U-Pb ages reveal coeval emplacement of these granitoids between 2.53 and 2.50 Ga. The HBG, including ME, has low silica, metaluminous affinity, and high ferromagnesian element content, consistent with their derivation from a mafic source. Some of the HBG and ME samples are strongly enriched in incompatible elements, similar to the sanukitoids. The geochemical attributes and strongly evolved zircon Hf isotopic compositions (ɛHf_(t) = −4.3 to +1.8 and −7.3 to +0.2) of the HBG and ME suggest their derivation from a mantle source metasomatized by subducted sediments. The BTG and MG are compositionally similar, with high silica, low ferromagnesian element content, and moderate peraluminous affinity, suggesting the involvement of felsic crustal sources. The sub-chondritic to chondritic zircon Hf isotopic compositions (ɛHf_(t) = −2.7 to +1.4 and  −6.9 to +1.9) of these granitoids support the involvement of heterogeneous ancient crustal sources. While all granitoids exhibit similar zircon Hf isotopic compositions, their geochemical attributes suggest distinct sources. The HBG reflects juvenile crustal additions, whereas BTG and MG are products of the crustal reworking. We propose that these granitoids formed during the continent-continent collision between Western and Eastern Dharwar cratons, that took place after the break-off of the eastward subducting slab. The asthenospheric upwelling induced by slab break-off and/or lithospheric delamination of thickened crust led to the genesis of metasomatized mantle derived magma, which drove the crustal reworking. The observed zircon Hf isotopic composition of the EDC granitoids are similar to the present day Phanerozoic Alpine-Himalayan type orogenies supporting subduction followed by continental collision model for the stabilisation of Archean cratons. Evidence for the existence of Paleo- Mesoarchean felsic crust from this part of the EDC warrants further studies to test the three-terrane model for the Dharwar Craton.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"488 ","pages":"Article 107807"},"PeriodicalIF":2.9,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427793","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":"Diversity of Siderian magmatic pulses revealed by intracrustal melting of oceanic crust in the Mineiro Belt, southern São Francisco Craton","authors":"Stéphany Rodrigues Lopes ,&nbsp;Leonardo Gonçalves ,&nbsp;Cristiane Castro Gonçalves ,&nbsp;Hugo Moreira ,&nbsp;Syro Lacerda ,&nbsp;Pedro Vieira Armond","doi":"10.1016/j.lithos.2024.107806","DOIUrl":"10.1016/j.lithos.2024.107806","url":null,"abstract":"<div><div>The early Paleoproterozoic Era has been largely recognized as a period of global magmatic slowdown (∼2.3–2.2 Ga). The Lagoa Dourada Suite, located in the Mineiro Belt – southern São Francisco Craton - Brazil, is a juvenile high‑aluminum 2350 Ma TTG suite and spatially associated with a network of dykes that received little attention in the literature. Based on field features, petrography, whole-rock geochemistry, U-Th-Pb, and Hf isotopes in zircons, we propose that these dykes represent three different magmatic pulses produced via intracrustal melting of oceanic crust. Pulse 1 (&lt;2347 Ma) is <em>syn</em>-plutonic with low-SiO₂, high-Mg# and HREE, moderate [La/Yb]_N, and low Ba+Sr contents. Pulse 2 (ca. &lt;2330 Ma) shows high-SiO₂, low-Mg# and HREE, moderate [La/Yb]_N, and high Ba+Sr. Pulse 3 (ca. &lt;2325 Ma) has intermediate-SiO₂, low-Mg#, high HREE, moderate to high [La/Yb]_N, and high Ba+Sr values. Their Hf compositions are broadly similar to those of the host rock, with positive εHf_(t) values and the Hf-T_DM model ages ranging from 2.65 to 2.46 Ga, attesting to their juvenile nature. These characteristics, coupled with their homogeneous Hf signature (¹⁷⁶Hf/¹⁷⁷Hf = 0.281382 to 0.281481), suggest that all these magmatic pulses came from a similar source. However, the whole-rock chemical diversity of the dykes and host rock suggests chemical heterogeneities within this source rock and/or the different magmatic pulses were generated by variable degrees of partial melting of a tholeiitic metabasaltic source throughout approximately 25 Ma. These findings reveal a wide compositional diversity of magmas that gave rise to a network of dykes crosscutting the Lagoa Dourada Suite and, consequently, to the framework of a juvenile continental crust on the southern margin of the São Francisco Craton. Furthermore, these rocks constitute a singular example of juvenile magmatism and contribute to a better understanding of the tectono-magmatic lull and potential petrological processes during this period.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"488 ","pages":"Article 107806"},"PeriodicalIF":2.9,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312924","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":"Very high-T hydration in the lower gabbro section of Semail ophiolite, Hydrous components of the lower crust at fast-spreading ridge","authors":"Françoise Boudier,&nbsp;David Mainprice,&nbsp;Adolphe Nicolas","doi":"10.1016/j.lithos.2024.107800","DOIUrl":"10.1016/j.lithos.2024.107800","url":null,"abstract":"<div><p>Totally fresh black gabbros are observed locally at the very base of the gabbro section in southern Semail ophiolite. Devoid of medium to low-temperature diffuse alteration, the black gabbros are characterized by cloudy plagioclase marked by a high density of hydrothermal inclusions below the optical microscope resolution, evolving into diopside and pargasite crystals ∼10 μm sized. They record hydration at temperature over 900 °C as shown by their major elements composition. Focused Electron Backscattered Electron Diffraction (EBSD) study of the crystalline inclusions, suggests a phase transition from diopside to amphibole, and traces consistent crystallographic relationships of diopside inclusions with their host plagioclase. The detailed geometry of the microcrack system traces a complete fluid path from inter-grain cracking, to plagioclase intra-grain network, possibly thermally-induced. The evidence of solid-state deformation overprinting the magmatic textures suggests that twinning mechanism in plagioclase controls the intra-grain diffusion of hydrous fluids. Located at the interface of the Moho Transition Zone (MTZ) and semi-brittle lithosphere, the ‘black gabbros’ record a narrow domain where focused fluid flow induces rapid cooling below the gabbro solidus at the lowest limit of the magma chamber.</p></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"488 ","pages":"Article 107800"},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142274269","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":"Dating syn-orogenic exhumation of subducted continental crust: The case of the Northern Apennines","authors":"Francesco Giuntoli ,&nbsp;Giulio Viola ,&nbsp;Igor M. Villa","doi":"10.1016/j.lithos.2024.107801","DOIUrl":"10.1016/j.lithos.2024.107801","url":null,"abstract":"<div><p>Dating deformation is key to unravel the evolution of orogens. Unfortunately, this is commonly challenged by the occurrence in the rock record of multiple overprinting deformation stages that lead to repeated blastesis and form multiple fabrics during both prograde and retrograde evolutions. Additionally, recrystallization is not always complete, which causes a mixture of inherited and neoblastic mineral phases. Therefore, an approach integrating age dating with microstructural and petrographic analyses is necessary to extract structurally constrained ages from the rock record. We used this approach to contribute to the long-lasting debate about exhumation of continental metamorphic units subducted to high-pressure conditions. We studied continental metasedimentary sequences of the Tuscan Metamorphic Units of the Northern Apennines (Italy) from two localities: the Island of Giglio to the west and the Monticiano-Roccastrada Unit to the east. We obtained two analytically distinct ⁴⁰Ar/³⁹Ar age ranges: an older 21–16 Ma age cluster is related to syn-orogenic top-to-the E contractional deformation occurring at ca. 1 GPa and 350 °C. A younger 15–11 Ma age group is related, instead, to exhumation to shallower structural levels and retrogression of these units to greenschist facies conditions. The interpretation of the results is based on white mica chemical compositions and rock fabrics. By integrating our results with published literature, we conclude that the investigated high-pressure continental metasedimentary sequences experienced early syn-orogenic exhumation from blueschist to greenschist facies conditions predominantly by a combination of extrusion and out- and in-sequence thrusting, with only minor contributions by extensional shearing during regional crustal thinning. Therefore, this study highlights the role of contractional fabrics in accommodating significant exhumation amounts of deeply subducted continental rocks.</p></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"488 ","pages":"Article 107801"},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0024493724003141/pdfft?md5=f606515b2680df2a48063bc61aaca446&pid=1-s2.0-S0024493724003141-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142172523","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":"Compositional diversity of late Mesozoic granites rooting from the subducted crust in the Qinling–Dabie orogenic belt","authors":"Jun He ,&nbsp;Zeqiu Qi ,&nbsp;Aimin Hu ,&nbsp;Zhiyi Wang ,&nbsp;Jiansen Li ,&nbsp;Fukun Chen","doi":"10.1016/j.lithos.2024.107785","DOIUrl":"10.1016/j.lithos.2024.107785","url":null,"abstract":"<div><p>Continental subduction has been identified in many orogens, such as the Alps, the Himalayas, and the Dabie; however, better understanding of the mechanism and outcome of different subduction processes remains desirable. The Qinling–Dabie orogen in Central China shows an asymmetric distribution of Triassic ultrahigh-pressure metamorphic rocks and <em>syn</em>- and post-tectonic granitoid plutons, thereby providing an excellent means by which to probe the diverse processes of continental subduction. Many late Mesozoic granitoid plutons that formed in post-orogenic or even anorogenic settings are widely distributed in both the Qinling and Dabie tectonic units and can be useful for studying the composition of materials beneath the crust because of their conspicuous compositional diversity. In the present study, we report zircon ages and Nd<img>Hf isotopic compositions for the Shangcheng and Heyu granite plutons, which represent late Mesozoic plutons in Dabie and Qinling. When compared with those of the Shangcheng pluton, the wide range of Nd isotopic values and the slightly depleted Hf isotopic compositions of the Heyu pluton indicate that there may be juvenile crust beneath the Qinling tectonic unit that is not present beneath the southern margin of North China. The currently undetectable juvenile material in this region may be an important candidate source of the late Mesozoic magmatism and metal mineralization in the southern margin of North China. The compositional diversity of these granites, as indicated by the Nd<img>Hf isotopic compositions, is attributed to the nature of the deep crust within the orogenic belt, and the magmatic origins of this region are discussed in the present study.</p></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"488 ","pages":"Article 107785"},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142167534","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":"Corrigendum to “Magnetization related to late-Variscan extensional collapse in the Lugo Dome (NW Iberian Massiff): A metamorphic petrology approach” [Lithos Volumes 484–485 (2024) 107745]","authors":"Manuela Durán Oreja ,&nbsp;Pavel Pitra ,&nbsp;Alicia López-Carmona ,&nbsp;José R. Martínez Catalán ,&nbsp;Puy Ayarza","doi":"10.1016/j.lithos.2024.107781","DOIUrl":"10.1016/j.lithos.2024.107781","url":null,"abstract":"","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"488 ","pages":"Article 107781"},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656728","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":"Generation of isotopically enriched giant Lincang Batholith by disequilibrium melting of the heterogeneous lower crust","authors":"Jin-Cheng Xie ,&nbsp;Di-Cheng Zhu ,&nbsp;Qing Wang ,&nbsp;Peter A. Cawood ,&nbsp;Zhi-Dan Zhao ,&nbsp;Qiong-Yao Zhan ,&nbsp;Jia-Hao Fan ,&nbsp;Yao Wang","doi":"10.1016/j.lithos.2024.107803","DOIUrl":"10.1016/j.lithos.2024.107803","url":null,"abstract":"<div><p>Deciphering the origin of granitoids with enriched isotopic compositions is essential to understanding the mechanism of continental growth and reworking. Establishing their origin is also an effective solution to the decoupled interpretations between geochemical and isotopic observations in competing petrogenetic models. This paper reports on the whole-rock major and trace elements, Sr-Nd-Pb-Hf isotopes, and zircon U<img>Pb age and Hf isotope data of samples from the Late Triassic Lincang Batholith in SW China. The hornblende-bearing granodiorites are weakly peraluminous, whereas the coeval biotite monzogranites are generally strongly peraluminous. These two types of granitoids show identical and extremely enriched isotopic compositions with (⁸⁷Sr/⁸⁶Sr)_i ratios of 0.71991 to 0.74302, whole-rock ε_Nd(t) values of −13.5 to −10.1, and ε_Hf(t) values of −13.4 to −10.3, as well as a large variation of zircon ε_Hf(t) values of −17.6 to +0.6. The inherited zircons from both suites of samples show similar age peaks (ca. 950 Ma and ca. 1150 Ma), trace element concentrations, and ε_Hf(t) variations to those of the detrital zircons from the Lancang Group. These similarities indicate that these rocks are most likely derived from the anatexis of the Lancang Group that is mainly composed of quartz schist, sericite schist, greenschist, chlorite albite schist, and minor eclogite. On the other hand, the Lancang Group is characterized by more enriched isotopic compositions than the granitic batholith with whole-rock ε_Nd(225 Ma) value of −13.3 and ε_Hf(225 Ma) value of −19.1, but identical to those of the average ε_Hf(225 Ma) values of inherited and detrital zircons (−18.1 and − 16.3). This isotopic fractionation between the granitoids and the Lancang Group may result from disequilibrium melting of the Lancang Group with different dissolution behavior of accessory minerals (i.e., zircon, monazite, apatite, titanite, etc.). The Lincang Batholith is on average more silicic and richer in incompatible elements than the upper continental crust, suggesting that the isotopically enriched giant granitic batholith is a mature magmatic response to continental reactivation and reworking.</p></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"488 ","pages":"Article 107803"},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240642","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}