Gondwana Research最新文献_第2页

Counterclockwise P-T-t path, cyclic crustal anatexis and magmatic tempo in accretionary orogens: A case study in the Devonian arc of Central Patagonia, Argentina

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2025-02-26 DOI: 10.1016/j.gr.2025.02.011

Emiliano M. Renda , Paulo Marcos , Sebastian Oriolo , Benita Putlitz , Lukas Baumgartner , Pablo González , Michelle L. Foley , Victor Ruiz González , Haroldo Vizán

An intriguing aspect of accretionary orogen dynamics is the crustal growth of the West Gondwana margin throughout the Terra Australis Orogeny, particularly regarding the development of the Patagonian crust and whether it involved periods of collisional or non-collisional orogenesis. This study examines the Devonian tectono-thermal evolution of the western North Patagonian Massif (southern South America), through the investigation of high-grade metamorphic rocks associated with the Devonian arc of Central Patagonia. Phase equilibrium modelling and geothermobarometry indicate an initial MP-HT metamorphic event (M1) under contractional conditions at the amphibolite- to granulite-facies transition, with metamorphic conditions of 6.7 ± 1 Kbar and ∼ 760 °C, previously dated at 379 ± 5 Ma. Successive crustal thickening and associated anatexis are recorded by metamorphic conditions at 8.9 ± 1 Kbar and ∼ 750 °C. Zircon U-Pb geochronology indicates leucosome crystallization at 360 ± 2 Ma, while an associated megacrystic granite records a 368 ± 2 Ma crystallization age, suggesting it represents an earlier magmatic pulse within the prolonged anatectic scenario. Decompression and cooling led to zircon crystallization near the solidus, marking an MP-MT (M₂) metamorphic event at amphibolite facies conditions (∼ 6.5 Kbar and 620 °C), recorded by zircon ages of 353 ± 2 Ma. A final retrograde metamorphic event (M₃) is recorded at ∼ 660 °C and ∼ 4.6 Kbar with monazite ages of 323 ± 5 Ma. This event is linked to decompression and intrusion of gondwanide magmatism. These metamorphic conditions reveals an overall counterclockwise P-T-t path for the Taquetren range from the Devonian to Carboniferous. Combined with the study of magmatic addition rates in the arc and forearc during the Devonian, this pattern supports an accretionary orogen model characterized by alternating periods of advancing and retreating subduction, potentially driven by trenchward and landward slab folding, which may account for short-cycle variation (∼15 Myr). These dynamic slab movements may have influenced variations in magmatic activity in the forearc and arc, coupled with shifts in metamorphic conditions and tectonic regimes.

增生造山动力学的一个耐人寻味的方面是西冈瓦纳边缘在整个大洋洲造山运动中的地壳增长，特别是巴塔哥尼亚地壳的发展，以及它是否涉及碰撞或非碰撞造山时期。本研究通过调查与巴塔哥尼亚中部泥盆纪弧相关的高品位变质岩，研究了北巴塔哥尼亚地块西部（南美洲南部）泥盆纪构造热演化。相平衡建模和地热测温表明，在闪长岩向花岗岩过渡的收缩条件下，发生了最初的MP-HT变质事件（M1），变质条件为6.7 ± 1 Kbar和 ∼ 760 °C，先前的年代为379 ± 5 Ma。8.9±1千巴和∼750 °C的变质条件记录了连续的地壳增厚和相关的无性变质。锆石U-Pb地质年代显示白云母结晶于360±2 Ma，而相关的巨晶花岗岩记录的结晶年龄为368±2 Ma，这表明它代表了延长的无恒星状态中较早的岩浆脉冲。减压和冷却导致锆石在固结点附近结晶，标志着在闪长岩面条件（6.5 千巴和 620 °C）下的 MP-MT（M2）变质事件，记录的锆石年龄为 353 ± 2 Ma。最后一次逆行变质事件（M3）发生在 ∼ 660 °C和 ∼ 4.6 Kbar，独居石年龄为 323 ± 5 Ma。这一事件与减压和贡万岩浆侵入有关。这些变质条件揭示了塔克特伦山脉从泥盆纪到石炭纪的整体逆时针P-T-t路径。结合对泥盆纪弧和前弧岩浆增加速率的研究，这一模式支持一个增生造山运动模型，其特点是俯冲前进和后退交替进行，可能由向沟和向陆板块褶皱驱动，这可能是短周期变化（15 Myr）的原因。这些动态的板块运动可能影响了前弧和弧中岩浆活动的变化，再加上变质条件和构造体系的转变。

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引用次数: 0

Jurassic picritic and potassic mafic dyke swarms in eastern China: Evidence for thermal erosion of the lithospheric mantle during Paleo-Pacific subduction

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2025-02-26 DOI: 10.1016/j.gr.2025.02.012

Wenjia Wang , Shuguang Song , Chao Wang , Mark B. Allen , Lifei Zhang , Xiaowei Li , Li Su

Paleo-Pacific subduction significantly impacted the structure and nature of the mantle in Eastern China. However, the thermal structure of the supra-subduction-zone mantle during the early stage of the Paleo-Pacific subduction has not been well constrained. Here, we present an integrated study involving field investigation, petrology, and geochemistry on two types of Jurassic (168–155 Ma) mafic dyke swarms in Western Liaoning, North China Craton (NCC), to trace the properties of the NCC mantle during the Jurassic. The picritic dyke swarms, trending NNW (330°–350°), show OIB-like geochemical signatures, with high mantle potential temperatures (Tp) ranging from 1498 ± 52°C to 1535 ± 56°C. These picritic dyke swarms are derived from high-degree of partial melting of the asthenospheric mantle by a hot and hydrous asthenospheric melts rising from the mantle transition zone above the subducted slab. In contrast, the Jurassic potassic mafic dyke swarms, trending NNW (325°–345°), were formed by partial melting of the metasomatized lithospheric mantle during the upwelling of the asthenospheric melts. We conclude that thermal erosion would be a major factor in the destruction of the lithospheric mantle beneath the NCC in the early stage of the Paleo-Pacific plate subduction.

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引用次数: 0

Retrieving petrogenetic source, compositional diversity and tectono-magmatic scenario of Tethyan sediment-derived magmatic flare-up: A tale from petrochemical and multi-isotopic (Sr–Nd–B–Hf) systematics 从岩石化学和多同位素（Sr-Nd-B-Hf）系统学的角度解读哲罗纪沉积物岩浆爆发的成岩来源、成分多样性和构造-岩浆情景：石油化学和多同位素（锶-钕-硼-铪）系统学的故事

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2025-02-26 DOI: 10.1016/j.gr.2025.02.013

Tehseen Zafar , Shuguang Song , Hafiz Ur Rehman , Hamed Gamaleldien , Abiola Oyebamiji , Zaheen Ullah , Umar Farooq Jadoon , Muhammad Farhan , Mohamed Zaki Khedr , Irfan Maqbool Bhat , Fatemeh Sepidbar , Fatemeh Nouri , Amjad Hussain , Zahid Hussain , Mabrouk Sami

The Earth’s continental crust is predominantly composed of granitic rocks, yet the genesis of pure sediment-derived peraluminous granites (PGs) remains debated. This study investigates the Ordovician Mansehra granitic suite (ca. 476–483 Ma) from the northwestern Himalayas of Pakistan as an example of S-type granites, comparing them with global counterparts from Diancangshan-Ailaoshan (China), Tanggula-Damxung (Tibet), and Karamese (Turkey). Geochemical and isotopic data, including variable zircon εHf(t) values (−37.7 to + 12.6), enriched Sr isotope ratios ((⁸⁷Sr/⁸⁶Sr)i: 0.5678–0.7444), negative εNd(t) values (−13.4 to − 2.9), and a narrow δ¹¹B range (−15.4 ‰ to − 9.5 ‰), indicate that PGs formed through partial melting of heterogeneous, mature pelitic sources under shallow, low-pressure conditions in the lower–upper crust, with minimal mantle input. Heterogeneous Hf isotopic behavior reflects the disequilibrium melting of variable metasedimentary protoliths. Geochemical modeling highlights fluid-flux melting as the dominant process, except for the Tanggula granites, which exhibit characteristics of fluid-absent melting. Tectonically, the Mansehra PGs are interpreted as products of Proto-Tethyan oceanic subduction beneath northern Gondwana, formed through the disequilibrium melting of exhumed back-arc basin sediments. Slab break-off likely triggered asthenospheric upwelling, enhancing heat flux and driving anatexis and PG production. While global PGs represent different geodynamic evolutionary contexts, they predominantly display significant tectonic events rather than direct contributions to crustal growth. The Mansehra PGs, along with similar granites, record large-scale anatexis linked to collisional tectonics, providing critical insights into Earth’s geodynamic evolution.

地球的大陆地壳主要由花岗岩组成，然而纯沉积物衍生的过铝花岗岩（PGs）的成因仍存在争议。本研究以巴基斯坦喜马拉雅山西北部的奥陶纪 Mansehra 花岗岩群（约 476-483 Ma）为例，研究了 S 型花岗岩，并将其与来自滇苍山-艾劳山（中国）、唐古拉-达姆松（西藏）和卡拉梅斯（土耳其）的全球同类花岗岩进行了比较。地球化学和同位素数据，包括可变的锆石εHf(t)值（-37.7 至 + 12.6）、富集的 Sr 同位素比（(87Sr/86Sr)i：0.5678-0.7444）、负的 εNd(t)值（-13.4 至 - 2.9）和较窄的 δ11B 范围（-15.4 ‰至- 9.5 ‰），表明PGs是在地壳下-上部浅层低压条件下，通过部分熔融异质、成熟的辉长岩源而形成的，地幔输入极少。不同的 Hf 同位素行为反映了不同的变质原岩的不平衡熔融。地球化学模型显示，流体流动熔融是主要的熔融过程，但唐古拉花岗岩除外，它们表现出流体缺失熔融的特征。从构造上看，曼塞赫拉花岗岩被解释为冈瓦纳北部下方原泰西期大洋俯冲的产物，是通过后弧盆地沉积物的非平衡熔融形成的。板岩断裂很可能引发了流体层上升流，从而增强了热通量，并推动了无氧运动和PG的生成。虽然全球 PGs 代表了不同的地球动力演化背景，但它们主要显示了重要的构造事件，而不是对地壳增长的直接贡献。曼塞赫拉 PGs 以及类似的花岗岩记录了与碰撞构造有关的大规模消长，为了解地球地球动力演化提供了重要信息。

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引用次数: 0

Carboniferous-Permian magmatism in western section of the North Qaidam, northern Tibet Plateau: Response to the spatio-temporal evolution of the Paleo-Tethys Ocean

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2025-02-21 DOI: 10.1016/j.gr.2025.02.007

Panlong Wang , Yongjun Li , Yujun Zhuang , Pingyang Gu , Gaoxue Yang , Fenghao Duan , Jianye Zhang , Wei Li , Nanhe Peng , Qian Wang , Hai Li

The origin of Late Paleozoic igneous rocks in the North Qaidam (NQ) remains controversial. This study presents comprehensive geochronological, geochemical, and isotopic data on the igneous rocks in western section of the NQ. The chronological results indicate that the Yanchangbeishan (YC) hornblende gabbro was formed at ca. 254 Ma; the Xiaosaishitengshan (XS) gabbro, biotite quartz-diorite, monzogranite, and andesite were formed at ca. 318 Ma, ca. 259 Ma, ca. 252 Ma, and ca. 271 Ma, respectively; and the Dasaishitengshan (DS) gabbro, tonalite, and biotite monzogranite were formed at ca. 268 Ma, ca. 272 Ma, and ca. 282 Ma, respectively. The Lu-Hf isotopic results show that the ε_Hf(t) values of YC hornblende gabbro, XS andesite, and DS gabbro and tonalite are + 1.21 to + 9.53, +9.01 to + 15.70, +0.05 to + 4.71, and − 5.43 to − 1.93, respectively. Among them, XS gabbro (high-alumina) and andesite, and YC gabbro (high-magnesium) exhibit significant depletions in Nb, Ta, and Ti, similar to island arc magmas, which formed by partial melting of depleted lithospheric mantle metasomatized by slab fluids to varying degrees. DS gabbro (high-Nb) shows slight depletions in Nb, Ta, and Ti, resembling intraplate rift basic rocks, and resulting from low-degree partial melting of depleted mantle wedge metasomatized by slab melts. XS biotite quartz-diorite, monzogranite, and DS biotite monzogranite have high SiO₂ (63.69–76.85 wt%) contents and low Mg^# values (28–43), classified as I-type granites, formed by partial melting of juvenile crust. DS tonalite (high Ba-Sr) shows depletions in Nb, Ta, and Ti, originating from the lithospheric mantle metasomatized by slab-derived fluids and undergoing extensive fractional crystallization. By integrating the results of this study with published work regarding the igneous rocks in the NQ, we propose a new tectonic evolution model involving Zongwulong Paleo-Tethys Ocean subduction slab roll-back and subduction zone retreat for the Late Paleozoic in the NQ.

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引用次数: 0

Decoding cycling and enrichment of boron and associated lithium in waters of the Tibetan Plateau with boron isotopes

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2025-02-12 DOI: 10.1016/j.gr.2025.02.006

Yu Zhang , Hongbing Tan , Zhiwei Shi , Fei Xue , Xiying Zhang , Huiying Ma

The Tibetan Plateau (TP), which has various water bodies exhibiting extreme enrichment of boron (B), lithium (Li) and other elements, is a unique and cost-effective supplier of B and Li globally. However, the sources and enrichment mechanisms of these elements remain disputed. Herein, big data on B isotopes and geochemistry were compiled to reveal cycling and enrichment of B and associated Li in the complex mountain-basin systems of the TP. Various water bodies on the TP show remarkably high B and Li concentrations compared with the global average levels. B and Li are supernormally enriched or even mineralized in some salt lakes, oilfield brines, and geothermal systems. Water with high B concentrations exhibits simultaneous ¹¹B depletion. The spatial patterns of B-Li concentrations and δ¹¹B values are characterized by a westward increase and a southward decrease, respectively. The mechanisms of B and Li cycling and enrichment, from source to sink, on the TP can be summarized as follows: 1) Slab subduction and following continental collisions induced partial melting of the mid-lower crust, resulting in late-stage highly differentiated crust-derived magma upwelling and invasion into the mid-upper crust. Hot springs thereby maintain an efficient release of abnormally abundant B and Li from magmatic fluids to the surface through deep geothermal circulation. 2) In the eastern and southeastern TP, Massive degassing of mantle fractions prevails along large strike-slip faults. B and Li enriched from mantle- or crust-derived fluids can reach the surface via local volcanism. 3) Water-rock interaction and weathering trigger further activation, mobilization, and enrichment of B and Li in water. The aforementioned geological processes supply constantly deep-source B and Li to rivers and groundwater as cold-hot springs. Eventually, B and Li are fed into the lake basin jointly with supergene processes; after prolonged evaporation-concentration, excellent B-Li-rich salt lake resources are formed.

{"title":"Decoding cycling and enrichment of boron and associated lithium in waters of the Tibetan Plateau with boron isotopes","authors":"Yu Zhang , Hongbing Tan , Zhiwei Shi , Fei Xue , Xiying Zhang , Huiying Ma","doi":"10.1016/j.gr.2025.02.006","DOIUrl":"10.1016/j.gr.2025.02.006","url":null,"abstract":"<div><div>The Tibetan Plateau (TP), which has various water bodies exhibiting extreme enrichment of boron (B), lithium (Li) and other elements, is a unique and cost-effective supplier of B and Li globally. However, the sources and enrichment mechanisms of these elements remain disputed. Herein, big data on B isotopes and geochemistry were compiled to reveal cycling and enrichment of B and associated Li in the complex mountain-basin systems of the TP. Various water bodies on the TP show remarkably high B and Li concentrations compared with the global average levels. B and Li are supernormally enriched or even mineralized in some salt lakes, oilfield brines, and geothermal systems. Water with high B concentrations exhibits simultaneous <sup>11</sup>B depletion. The spatial patterns of B-Li concentrations and δ<sup>11</sup>B values are characterized by a westward increase and a southward decrease, respectively. The mechanisms of B and Li cycling and enrichment, from source to sink, on the TP can be summarized as follows: 1) Slab subduction and following continental collisions induced partial melting of the mid-lower crust, resulting in late-stage highly differentiated crust-derived magma upwelling and invasion into the mid-upper crust. Hot springs thereby maintain an efficient release of abnormally abundant B and Li from magmatic fluids to the surface through deep geothermal circulation. 2) In the eastern and southeastern TP, Massive degassing of mantle fractions prevails along large strike-slip faults. B and Li enriched from mantle- or crust-derived fluids can reach the surface via local volcanism. 3) Water-rock interaction and weathering trigger further activation, mobilization, and enrichment of B and Li in water. The aforementioned geological processes supply constantly deep-source B and Li to rivers and groundwater as cold-hot springs. Eventually, B and Li are fed into the lake basin jointly with supergene processes; after prolonged evaporation-concentration, excellent B-Li-rich salt lake resources are formed.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"141 ","pages":"Pages 120-134"},"PeriodicalIF":7.2,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A review of Mesozoic geodynamic evolution of the North Makran (SE Iran): A tale of a Neo-Tethyan ocean vanished due to two coexisting subduction zones

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2025-02-12 DOI: 10.1016/j.gr.2025.01.016

Edoardo Barbero , Luca Pandolfi , Morteza Delavari , Asghar Dolati , Emilio Saccani , Maria Di Rosa , Michele Marroni

This paper presents a synthesis of the geological features of each tectonic unit of the North Makran (SE Iran), integrating results of multidisciplinary analyses, including structural and stratigraphic studies, petrographic and geochemical analyses, thermobarometric studies, as well as biostratigraphic and geochronological dating. This wealth of data forms the basis for a novel geodynamic model of the Jurassic − Eocene evolution of the Neo-Tethys realm, which evolved between the Arabian Plate and the Lut Block. The features of the North Makran tectonic units support the existence of a mid-ocean ridge setting during the Jurassic – Early Cretaceous. Contrary to previous interpretations, the data from these tectonic units suggests a single oceanic basin separating the Arabian and Lut continental margins, without the interposition of a microcontinental block. In the Early Cretaceous, subduction initiation is recorded by volcanic arc assemblages accommodating the convergence between the Arabian Plate and Lut Block. The nucleation of an intra-oceanic subduction marked the separation of the North Makran Ocean from the Neo-Tethys. The Late Cretaceous was characterized by plume-related magmatism and the onset of the convergence in the North Makran Ocean, inducing its subduction beneath the Lut Block. This subduction is recorded by volcanic arc assemblage and high pressure and low-temperature metamorphism within a subduction complex. Meanwhile, intra-oceanic subduction persisted within the Neo-Tethys, accompanied by a subduction complex and arc magmatism. The final closure of the North Makran Ocean occurred during the Late Cretaceous –Late Paleocene with the progressive amalgamation of the two subduction complexes and the deformation of the interposing oceanic lithosphere. This study suggests that the subduction of a seamount chain in the North Makran Ocean played a key role in the shortening and closure of this basin. This research emphasizes the importance of considering multiple factors in understanding the tectonic evolution of the Neo-Tethys realm.

{"title":"A review of Mesozoic geodynamic evolution of the North Makran (SE Iran): A tale of a Neo-Tethyan ocean vanished due to two coexisting subduction zones","authors":"Edoardo Barbero , Luca Pandolfi , Morteza Delavari , Asghar Dolati , Emilio Saccani , Maria Di Rosa , Michele Marroni","doi":"10.1016/j.gr.2025.01.016","DOIUrl":"10.1016/j.gr.2025.01.016","url":null,"abstract":"<div><div>This paper presents a synthesis of the geological features of each tectonic unit of the North Makran (SE Iran), integrating results of multidisciplinary analyses, including structural and stratigraphic studies, petrographic and geochemical analyses, thermobarometric studies, as well as biostratigraphic and geochronological dating. This wealth of data forms the basis for a novel geodynamic model of the Jurassic − Eocene evolution of the Neo-Tethys realm, which evolved between the Arabian Plate and the Lut Block. The features of the North Makran tectonic units support the existence of a mid-ocean ridge setting during the Jurassic – Early Cretaceous. Contrary to previous interpretations, the data from these tectonic units suggests a single oceanic basin separating the Arabian and Lut continental margins, without the interposition of a microcontinental block. In the Early Cretaceous, subduction initiation is recorded by volcanic arc assemblages accommodating the convergence between the Arabian Plate and Lut Block. The nucleation of an intra-oceanic subduction marked the separation of the North Makran Ocean from the Neo-Tethys. The Late Cretaceous was characterized by plume-related magmatism and the onset of the convergence in the North Makran Ocean, inducing its subduction beneath the Lut Block. This subduction is recorded by volcanic arc assemblage and high pressure and low-temperature metamorphism within a subduction complex. Meanwhile, intra-oceanic subduction persisted within the Neo-Tethys, accompanied by a subduction complex and arc magmatism. The final closure of the North Makran Ocean occurred during the Late Cretaceous –Late Paleocene with the progressive amalgamation of the two subduction complexes and the deformation of the interposing oceanic lithosphere. This study suggests that the subduction of a seamount chain in the North Makran Ocean played a key role in the shortening and closure of this basin. This research emphasizes the importance of considering multiple factors in understanding the tectonic evolution of the Neo-Tethys realm.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"141 ","pages":"Pages 74-101"},"PeriodicalIF":7.2,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Reactionary interaction of upper mantle minerals with SiC at 6 GPa and 1100–1500 °C: Implication for moissanite appearance in ophiolitic peridotite and other uncommon natural environments

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2025-02-11 DOI: 10.1016/j.gr.2025.02.005

K.D. Litasov , A. Shatskiy , A.V. Arefiev , H. Kagi

Experiments were carried out on the interaction of mantle rocks and minerals with SiC at 6 GPa and 1100–1500 °C. Fine powders of natural peridotites and eclogites from kimberlites with the addition of 10 wt% SiC, as well as monomineralic powders and crystals of chromite, olivine, and garnet, were used as starting materials. The experiments were carried out on a 1500-ton multianvil press. In all experiments, the reduction of silicates and chromite was observed with an increase in the magnesium number (Mg#=100 Mg/(Mg + Fe)) of minerals to 97–100 % and the precipitation of metallic phases − alloys in the Fe-Ni and Fe-Si-Cr systems. The most pronounced reactions occurred at 1500 °C. Equilibrium was not reached in all the studied systems even after 72 h of annealing at 1300 °C. Instead, reaction rims were formed on mineral grains and finely dispersed iron alloys were precipitated throughout the volume of crystals. The reaction between SiC and chromite was fastest. The Mg# of chromite changed from 57 (in the initial chromite) to 80–94 %. It was shown that at 6 GPa, SiC reacted quickly with minerals and mantle rocks to form metal phases, high-magnesian silicates, and chromite. This means that they cannot be in equilibrium, as was previously stated for ophiolite peridotite and chromitite, and volcanic rocks such as basalts and kimberlites. The kinetic relationships indicate that a few millimeter grains of SiC can survive in the fluid-free mantle during subduction-exhumation only in cold environments below 700–800 °C. We believe that SiC in most natural rocks is related to anthropogenic contamination. In rare cases, which should be carefully documented, moissanite may have a natural terrestrial origin related to very localized events of formation of highly reduced hydrogen-bearing fluids.

{"title":"Reactionary interaction of upper mantle minerals with SiC at 6 GPa and 1100–1500 °C: Implication for moissanite appearance in ophiolitic peridotite and other uncommon natural environments","authors":"K.D. Litasov , A. Shatskiy , A.V. Arefiev , H. Kagi","doi":"10.1016/j.gr.2025.02.005","DOIUrl":"10.1016/j.gr.2025.02.005","url":null,"abstract":"<div><div>Experiments were carried out on the interaction of mantle rocks and minerals with SiC at 6 GPa and 1100–1500 °C. Fine powders of natural peridotites and eclogites from kimberlites with the addition of 10 wt% SiC, as well as monomineralic powders and crystals of chromite, olivine, and garnet, were used as starting materials. The experiments were carried out on a 1500-ton multianvil press. In all experiments, the reduction of silicates and chromite was observed with an increase in the magnesium number (Mg#=100 Mg/(Mg + Fe)) of minerals to 97–100 % and the precipitation of metallic phases − alloys in the Fe-Ni and Fe-Si-Cr systems. The most pronounced reactions occurred at 1500 °C. Equilibrium was not reached in all the studied systems even after 72 h of annealing at 1300 °C. Instead, reaction rims were formed on mineral grains and finely dispersed iron alloys were precipitated throughout the volume of crystals. The reaction between SiC and chromite was fastest. The Mg# of chromite changed from 57 (in the initial chromite) to 80–94 %. It was shown that at 6 GPa, SiC reacted quickly with minerals and mantle rocks to form metal phases, high-magnesian silicates, and chromite. This means that they cannot be in equilibrium, as was previously stated for ophiolite peridotite and chromitite, and volcanic rocks such as basalts and kimberlites. The kinetic relationships indicate that a few millimeter grains of SiC can survive in the fluid-free mantle during subduction-exhumation only in cold environments below 700–800 °C. We believe that SiC in most natural rocks is related to anthropogenic contamination. In rare cases, which should be carefully documented, moissanite may have a natural terrestrial origin related to very localized events of formation of highly reduced hydrogen-bearing fluids.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"141 ","pages":"Pages 102-119"},"PeriodicalIF":7.2,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Recent increase in soil moisture levels concerning climate variability in the karst region of southwest China using wavelet coherence and multi-linear regression

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2025-02-07 DOI: 10.1016/j.gr.2025.02.002

Azfar Hussain , Huizeng Liu , Jianhua Cao , Hui Yang , Abolfazl Rezaei , Pei Wang , Qukan Luo , Mengxia Zhou , Zhong Liang

Classifying climate-induced variations in soil moisture (SM) is vital in the face of climate change to enhance vegetation restoration and decrease rocky desertification in karst areas. In this paper, the Monotonic Mann-Kendall and Sen’s Slope test are used to assess the changes in SM and regional climatic variables from 1981 to 2019 across the karst region of southwest China (KRSC) using the ERA5 SM at 0–7, 7–28 and 28–100 cm. By utilizing wavelet coherence and multi-linear regression (MLR), we assess the association of SM with local climatic factors and teleconnections. Our findings indicate increased SM, NDVI, temperature (TMP), and precipitation (PCP) from 2002 to 2019 in the KRSC. The combined variance of the first and second EOF for 0–7, 7–28, and 28–100 cm showed 55 %, 52 %, and 44 %, respectively. The findings revealed a dominant influence of PCP and sensible heat fluxes (SHF) in SM for 8–120 months (∼1–10 years) periodic cycles, whereas the teleconnections showed consistent patterns in karst and non-karst regions. For integrated factors, PCP + actual evapotranspiration (AET), NDVI + SHF and long-wave radiation (LWR) + SHF showed mean significant coherences between 0.70 and 0.80, whereas ENSO + PDO + NAO (0.71–0.76) explained high coherence in comparison to other combinations. The karst SM showed a significant correlation with PCP (0.63–0.89), LWR (0.59–0.77), and SHF (0.76–0.95), while non-karst exhibited a significant correlation with ENSO (0.07–0.49), PDO (0.16–0.41) and PNA (0.10–0.38) in all seasons. The MLR identified PCP, SHF and LWR as the leading influencing variables in the karst region, whereas PCP and LWR showed more influence in the non-karst region for 0–7 cm. Our findings give valuable insights regarding sustainable SM management to promote vegetation and reduce rocky desertification.

{"title":"Recent increase in soil moisture levels concerning climate variability in the karst region of southwest China using wavelet coherence and multi-linear regression","authors":"Azfar Hussain , Huizeng Liu , Jianhua Cao , Hui Yang , Abolfazl Rezaei , Pei Wang , Qukan Luo , Mengxia Zhou , Zhong Liang","doi":"10.1016/j.gr.2025.02.002","DOIUrl":"10.1016/j.gr.2025.02.002","url":null,"abstract":"<div><div>Classifying climate-induced variations in soil moisture (SM) is vital in the face of climate change to enhance vegetation restoration and decrease rocky desertification in karst areas. In this paper, the Monotonic Mann-Kendall and Sen’s Slope test are used to assess the changes in SM and regional climatic variables from 1981 to 2019 across the karst region of southwest China (KRSC) using the ERA5 SM at 0–7, 7–28 and 28–100 cm. By utilizing wavelet coherence and multi-linear regression (MLR), we assess the association of SM with local climatic factors and teleconnections. Our findings indicate increased SM, NDVI, temperature (TMP), and precipitation (PCP) from 2002 to 2019 in the KRSC. The combined variance of the first and second EOF for 0–7, 7–28, and 28–100 cm showed 55 %, 52 %, and 44 %, respectively. The findings revealed a dominant influence of PCP and sensible heat fluxes (SHF) in SM for 8–120 months (∼1–10 years) periodic cycles, whereas the teleconnections showed consistent patterns in karst and non-karst regions. For integrated factors, PCP + actual evapotranspiration (AET), NDVI + SHF and long-wave radiation (LWR) + SHF showed mean significant coherences between 0.70 and 0.80, whereas ENSO + PDO + NAO (0.71–0.76) explained high coherence in comparison to other combinations. The karst SM showed a significant correlation with PCP (0.63–0.89), LWR (0.59–0.77), and SHF (0.76–0.95), while non-karst exhibited a significant correlation with ENSO (0.07–0.49), PDO (0.16–0.41) and PNA (0.10–0.38) in all seasons. The MLR identified PCP, SHF and LWR as the leading influencing variables in the karst region, whereas PCP and LWR showed more influence in the non-karst region for 0–7 cm. Our findings give valuable insights regarding sustainable SM management to promote vegetation and reduce rocky desertification.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"141 ","pages":"Pages 40-54"},"PeriodicalIF":7.2,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143376839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Spatial and temporal distribution, fate, and potential health risks of microplastics in urban indoor air

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2025-02-06 DOI: 10.1016/j.gr.2025.01.015

Liyuan Peng , Na Zheng , Qirui An , Xiaoqian Li , Siyu Sun , Yunyang Li , Jingze Yu , Fan Shao , Yingxi Qiu , Shuyue Zhang

The growing awareness of microplastics (MPs) in indoor residential environments stems from their pervasive presence and potential health risks. MPs were collected from living rooms and bedrooms, and their accumulation in the lungs of residents in three urban cities during summer and winter was assessed. The abundance of MPs at ≤ 2.5 μm and ≤ 10 μm was determined (Changchun: 713 ± 477 and 4239 ± 2420, Xingtai: 1003 ± 726 and 3781 ± 2070, Guangzhou: 492 ± 479 and 2446 ± 903, item/m³/day). Nearly 50 % of the total abundance of MPs discovered in this study were ≤ 10 μm in size. Considerable differences in MPs abundance were observed between summer and winter (p < 0.01). The quantity of MPs in residential settings correlated with lifestyle choices and ventilation time (p < 0.05). Fragments represented the primary shape of MPs (45 % – 68 %), with polyamide (PA; 5 % – 35 %) and polycarbonate (PC; 5 % – 33 %) being the predominant polymers. Indoor uptake of MPs in lungs varied by age group. Adults had the highest intake, followed by teenagers and older individuals, while children had the lowest intake. Children and adults were estimated to intake 530 – 2060 and 1046 – 4068 items/day of MPs, respectively. Additionally, living rooms and bedrooms exhibited medium to extreme hazards according to the pollutant loading index (PLI) and polymer hazard index (PHI) assessments. This study deepens our understanding of MPs pollution in urban indoor air, raises awareness of the health risks to lungs associated with MPs exposure, and provides data to support these findings.

{"title":"Spatial and temporal distribution, fate, and potential health risks of microplastics in urban indoor air","authors":"Liyuan Peng , Na Zheng , Qirui An , Xiaoqian Li , Siyu Sun , Yunyang Li , Jingze Yu , Fan Shao , Yingxi Qiu , Shuyue Zhang","doi":"10.1016/j.gr.2025.01.015","DOIUrl":"10.1016/j.gr.2025.01.015","url":null,"abstract":"<div><div>The growing awareness of microplastics (MPs) in indoor residential environments stems from their pervasive presence and potential health risks. MPs were collected from living rooms and bedrooms, and their accumulation in the lungs of residents in three urban cities during summer and winter was assessed. The abundance of MPs at ≤ 2.5 μm and ≤ 10 μm was determined (Changchun: 713 ± 477 and 4239 ± 2420, Xingtai: 1003 ± 726 and 3781 ± 2070, Guangzhou: 492 ± 479 and 2446 ± 903, item/m<sup>3</sup>/day). Nearly 50 % of the total abundance of MPs discovered in this study were ≤ 10 μm in size. Considerable differences in MPs abundance were observed between summer and winter (<em>p</em> < 0.01). The quantity of MPs in residential settings correlated with lifestyle choices and ventilation time (<em>p</em> < 0.05). Fragments represented the primary shape of MPs (45 % – 68 %), with polyamide (PA; 5 % – 35 %) and polycarbonate (PC; 5 % – 33 %) being the predominant polymers. Indoor uptake of MPs in lungs varied by age group. Adults had the highest intake, followed by teenagers and older individuals, while children had the lowest intake. Children and adults were estimated to intake 530 – 2060 and 1046 – 4068 items/day of MPs, respectively. Additionally, living rooms and bedrooms exhibited medium to extreme hazards according to the pollutant loading index (PLI) and polymer hazard index (PHI) assessments. This study deepens our understanding of MPs pollution in urban indoor air, raises awareness of the health risks to lungs associated with MPs exposure, and provides data to support these findings.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"141 ","pages":"Pages 1-12"},"PeriodicalIF":7.2,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Pre-Himalayan crustal evolution in the northern margin of India: Implications from zircon U–Pb, Hf and O isotope study of Chhota Shigri granitoids, Himachal Himalaya, Northwest India

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2025-02-06 DOI: 10.1016/j.gr.2025.02.001

Waikhom Nongdon , Bidyananda Maibam , Pankaj Kumar , Yoann Gréau , Jasper Berndt , Stephen Foley , Atul Kumar Singh , Deeksha Khandelwal

A systematic geochemical, geochronological (U−Pb), and isotopic study (Lu−Hf and O) of zircons from the northern margin of India has been carried out to understand the pre-Himalayan crustal evolution along the area. The rocks were characterized as granitoid and yielded two significant age peaks: 1018–715 Ma and 516–476 Ma, with sparse inherited cores of Paleoproterozoic to Archean ages, defining two major magmatic events (Tonian and Cambro-Ordovician) in the NW Himalaya. While Tonian ages are preserved in the zircon cores, the rims and numerous whole grains record the younger Cambro-Ordovician event. The Tonian zircon cores display εHf values ranging from –5.9 to +8.3, indicating both juvenile mantle-derived and recycled crustal sources. The Tonian zircon cores yield single-stage Hf model (T_DM) ages of 1.66–1.19 Ga and δ¹⁸O values of 5.75–10.88‰, suggesting that Tonian granitoids formed from mixed sources comprising juvenile material, recycled ancient crust and δ¹⁸O-rich supracrustal components. The Cambro-Ordovician zircons yielded εHf values from –27.4 to –4.0 and single-stage Hf model (T_DM) ages of 2.16–1.21 Ga, demonstrating extensive reworking of both Neoproterozoic crust and ancient crust occurred during the Cambro-Ordovician magmatism. Their elevated δ¹⁸O values (8.05–11.35‰) further support widespread crustal remelting with substantial incorporation of δ¹⁸O-rich supracrustal materials. These evidence the preservation of supercontinent (Rodinia) components within the NW Himalaya.

{"title":"Pre-Himalayan crustal evolution in the northern margin of India: Implications from zircon U–Pb, Hf and O isotope study of Chhota Shigri granitoids, Himachal Himalaya, Northwest India","authors":"Waikhom Nongdon , Bidyananda Maibam , Pankaj Kumar , Yoann Gréau , Jasper Berndt , Stephen Foley , Atul Kumar Singh , Deeksha Khandelwal","doi":"10.1016/j.gr.2025.02.001","DOIUrl":"10.1016/j.gr.2025.02.001","url":null,"abstract":"<div><div>A systematic geochemical, geochronological (U−Pb), and isotopic study (Lu−Hf and O) of zircons from the northern margin of India has been carried out to understand the pre-Himalayan crustal evolution along the area. The rocks were characterized as granitoid and yielded two significant age peaks: 1018–715 Ma and 516–476 Ma, with sparse inherited cores of Paleoproterozoic to Archean ages, defining two major magmatic events (Tonian and Cambro-Ordovician) in the NW Himalaya. While Tonian ages are preserved in the zircon cores, the rims and numerous whole grains record the younger Cambro-Ordovician event. The Tonian zircon cores display εHf values ranging from –5.9 to +8.3, indicating both juvenile mantle-derived and recycled crustal sources. The Tonian zircon cores yield single-stage Hf model (T<sub>DM</sub>) ages of 1.66–1.19 Ga and δ<sup>18</sup>O values of 5.75–10.88‰, suggesting that Tonian granitoids formed from mixed sources comprising juvenile material, recycled ancient crust and δ<sup>18</sup>O-rich supracrustal components. The Cambro-Ordovician zircons yielded εHf values from –27.4 to –4.0 and single-stage Hf model (T<sub>DM</sub>) ages of 2.16–1.21 Ga, demonstrating extensive reworking of both Neoproterozoic crust and ancient crust occurred during the Cambro-Ordovician magmatism. Their elevated δ<sup>18</sup>O values (8.05–11.35‰) further support widespread crustal remelting with substantial incorporation of δ<sup>18</sup>O-rich supracrustal materials. These evidence the preservation of supercontinent (Rodinia) components within the NW Himalaya.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"141 ","pages":"Pages 55-73"},"PeriodicalIF":7.2,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0