地球科学最新文献

{"title":"Petrogenesis and U-Pb zircon age of the Anorthosite-Gabbronorite association near Barabar Hill, Chotanagpur Granite Gneiss Complex (CGGC), eastern Indian shield","authors":"Priyanka Negi ,&nbsp;Ashima Saikia ,&nbsp;Ivan Belousov ,&nbsp;Leonid V. Danyushevsky ,&nbsp;Mansoor Ahmad ,&nbsp;Salim Akhtar","doi":"10.1016/j.precamres.2025.107940","DOIUrl":"10.1016/j.precamres.2025.107940","url":null,"abstract":"<div><div>Massif-type anorthosite intrusions represent critical archives of Proterozoic mantle-crust interactions, crustal accretion and reworking processes. These voluminous, plagioclase-dominated cumulates were emplaced predominantly during the Statherian-Tonian period (1.8–0.9 Ga), and temporally associated with the assembly of Columbia and Rodinia supercontinents. Despite their widespread occurrences during the restricted time interval, the petrogenesis of massif-type anorthosite remains contentious. Competing models invoke derivation from upwelling mantle melts, partial melting of lower crust and/or magmatism within subduction-related arc settings. Their enigmatic origin and temporal confinement highlight their significance in deciphering Proterozoic tectono-magmatic evolution. The Barabar Hill anorthosite-gabbronorite association, located in the northern Chotanagpur Granite Gneissic Complex (CGGC) of Bihar (India), represents a previously undocumented Paleoproterozoic anorthosite magmatism that sheds new light on the genesis of anorthosites and the overall crustal evolution of the eastern Indian Shield. This study integrates field observations, petrography, bulk-rock major and trace element geochemistry, mineral chemistry, and U–Pb zircon geochronology to constrain the (1) source, (2) parental melt composition, (3) role of crustal contamination, if any, and (4) emplacement age of the Barabar Hill anorthosite − gabbronorite association. Thermobarometric calculations suggest that clinopyroxenes in the gabbronorites crystallized at 1100–1175 °C and 0.04–2.30 kbar, and zircons in the anorthosites crystallized at 600–765 °C under FMQ buffer conditions. Equilibrium Distribution Method (EDM) constrain parental melt compositions at TMF = 0–20 % for the anorthosites and 15–30 % for the gabbronorites. Assimilation–Fractional Crystallization (AFC) modelling suggests derivation of the anorthosites from a depleted mantle source with significant contributions from upper crustal materials.</div><div>U-Pb zircon geochronology constrains the emplacement age of the Barabar Hill suite to 1760.8 ± 7.3 to 1762.0 ± 3.8 Ma (Statherian period), thus representing the first record of Paleoproterozoic anorthosite magmatism in the eastern Indian Shield. The Barabar Hill anorthosite represents a globally significant example of subduction-related magmatism, distinct from Archean megacrystic and Proterozoic massif-type anorthosites. The findings of this study suggests that anorthosites massifs were formed from basaltic magmas derived from the depleted mantle which was contaminated by upper crustal granitic materials. A hybrid mantle-crust origin for anorthosites expand our current understanding of Proterozoic crustal evolution.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"431 ","pages":"Article 107940"},"PeriodicalIF":3.2,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145327143","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":"Experimental differentiation of kimberlitic to carbonatitic melts: crystallization sequence and liquid line of descent","authors":"Rebecca F. Zech,&nbsp;Max W. Schmidt,&nbsp;Andrea Giuliani","doi":"10.1007/s00410-025-02273-x","DOIUrl":"10.1007/s00410-025-02273-x","url":null,"abstract":"<div><p>Kimberlites are volatile-rich, silica-undersaturated, mantle-derived magmas with an important role in studying mantle geochemistry, yet their compositional evolution during crystallization remains poorly constrained. This study defines the crystallization sequence and liquid line of descent of a reconstructed kimberlitic melt, using high-pressure experiments at 1–3 GPa and 1100–1400 °C. Early crystallization is dominated by olivine ± chromite, consistent with petrographic observations of natural samples, followed by clinopyroxene, ilmenite, perovskite, apatite, and phlogopite. The absence of clinopyroxene in natural kimberlitessuggests that kimberlitic melts remain above 1150 °C at 1 GPa, conditions at which clinopyroxene is not observed in our experiments. Substantial cooling of kimberlitic melt and related abundant crystallization likely occur in the crust, possibly linked to extensive degassing at shallow pressures. The experimental melts evolve continuously through decreasing SiO₂ and MgO, and enrichment in CaO, alkalis (Na, K), and volatiles (CO₂, H₂O), ultimately transitioning at ≤ 1150 °C to carbonatitic melts with 7–10 wt% SiO₂, 6.5–7.5 wt% Na₂O + K₂O, and up to 35 wt% volatiles. Olivine (± clinopyroxene) fractionation drives Si depletion at almost constant MgO + FeO + CaO and moderate alkali-enrichment, such that the carbonate-silicate miscibility gap is bypassed. This evolution is in sharp contrast to mafic alkaline silicate melts where olivine + clinopyroxene crystallization causes Si enrichment hence promoting melt evolution towards the carbonate-silicate miscibility gap. Overall, the experimental results demonstrate a petrogenetic continuum between kimberlitic and carbonatitic melts and provide constraints on the crystallization conditions of kimberlitic melts.</p></div>","PeriodicalId":526,"journal":{"name":"Contributions to Mineralogy and Petrology","volume":"180 12","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00410-025-02273-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145327655","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":"Petrogenesis of the Paleoproterozoic Liuying hornblendite arc cumulates and implications for the tectonic evolution of the northern North China Craton","authors":"Wen-Mei Liu ,&nbsp;Jian-Ping Zheng ,&nbsp;Bernard Charlier ,&nbsp;Qiang Ma ,&nbsp;Timothy Kusky ,&nbsp;Hong-Kun Dai","doi":"10.1016/j.precamres.2025.107946","DOIUrl":"10.1016/j.precamres.2025.107946","url":null,"abstract":"<div><div>Understanding the Paleoproterozoic configuration of the northern North China Craton (NCC) is crucial for reconstructing its Precambrian tectonic history. This study integrates geological field observations, petrological data, U-Pb geochronology, and Lu-Hf isotopic analysis of zircons, alongside mineral and whole-rock geochemistry, including Sr-Nd isotopes from the Liuying ultramafic complex in Hebei Province. Our goal is to enhance the understanding of the tectonic history of the craton’s northern margin. The complex is composed of hornblendite and plagioclase hornblendite, showing igneous cumulate texture. Zircon U-Pb data from the ultramafic complex define three distinct groups of ages: 2211–2343 Ma, 1761–1999 Ma, and 246–310 Ma, corresponding to magma crystallization and metamorphism resulted from crustal thermal events. The major elements of rocks align with the differentiation trend of hydrous arc magmas. They display characteristics of enrichment in large ion lithophile elements and depletion in high field strength elements. Fractional crystallization of arc magmas with H₂O of 7.3–8.1 wt% at middle-lower crust depths (18–23 km) and 966–996 °C formed amphibole-enrichment arc cumulates. The zircon ε_Hf(t) values (–5.96 to + 9.05) are decoupled from enriched Sr-Nd isotopic compositions ((⁸⁷Sr/⁸⁶Sr)_i = 0.704185–0.705932, ε_Nd(t) = −14.6 to −5.68, (⁸⁷Sr/⁸⁶Sr)_amp = 0.705110–0.705846), suggesting a subduction-modified mantle source, incorporating 5–10 % subduction slab-derived melts and fluids. The northern part of the NCC was a continental arc above a paleo-subduction zone on a scale similar to the modern Andes at ca. 2.2 Ga. The oceanic slab subduction between the craton and the Siberian segment resulted in partial melting of metasomatized mantle wedge to form Paleoproterozoic hornblendite arc cumulates.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"431 ","pages":"Article 107946"},"PeriodicalIF":3.2,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145327142","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":"Mechanistic insights for (alkyl)methacrylate-based cationic hybrid gels reinforced with sepiolite, montmorillonite, mica, bentonite and kaolin: A comparative thermodynamic study with all-in-one formulations","authors":"Beril Tanc Kaya ,&nbsp;Rabia Bozbay ,&nbsp;Nermin Orakdogen","doi":"10.1016/j.clay.2025.108016","DOIUrl":"10.1016/j.clay.2025.108016","url":null,"abstract":"<div><div>A series of clay-based cationic hybrids from <em>N</em>,<em>N</em>-dimethylaminoethyl methacrylate and 2-acrylamido-2-methyl-1-propanesulfonic acid in the presence of various clays; montmorillonite (Mt), bentonite (Bnt), sepiolite (Sep), kaolin and mica was prepared by in-situ free-radical polymerization. The primary objective was to understand the macroscale properties of ionically modified (alkyl)methacrylate-based polymers reinforced with nanometer-sized clays. Water absorption, repeated on-off switching in salt solutions, elasticity and efficiency in removal of anionic indigo carmine (IC) dye, widely used in textile industry for denim production, were comparatively analyzed depending on the clay type. Compared to Sep and Mt-integrated hybrids, the mechanical property was weaker due to the inhomogeneous distribution in the structure, while the mica and kaolin-integrated gels were resistant to high compression. Mt- and Sep-addition increased the swelling by four-fold, while the swelling in the presence of mica was limited. Hybrids exhibited good salt resistance and pH-sensitive swelling, with largest change in the volume being observed in Mt-doped gels, while least change was in Kaolin-doped ones. Based on the effect of salinity, the swelling of hybrids in aqueous solutions of monovalent and divalent metal nitrates followed the decreasing order as KNO₃ &gt; NaNO₃ &gt; Ba(NO₃)₂. Regardless of clay type, hybrid cryogels prepared at low polymerization temperature followed Fickian diffusion, while at higher temperatures, the clay type altered the mechanism and non-Fickian diffusion was observed in hybrid hydrogels doped with Mt, kaolin and mica. Anionic IC adsorption, which reached equilibrium in 30 min, varied between 93.4 % and 97.6 %. The presence of Kaolin and Bnt caused a significant increase in adsorption, while a decrease was observed in presence of Sep. Adsorption isotherms determined by three parameter models were compared with two-parameter models in linear and non-linear fitting of equilibrium data; Freundlich isotherm model and pseudo-first order kinetic model had the best fitness. Comparative results demonstrated that clay-integrated (alkyl)methacrylate-based cationic hybrids can be employed as effective and economical adsorbents for removal of anionic dyes from aqueous environments.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"279 ","pages":"Article 108016"},"PeriodicalIF":5.8,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145327140","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":"Pre-Mesoproterozoic crustal framework and Mesoproterozoic evolution of the SW Angolan Shield: structural, geochemical, and isotopic insights from the Kunene Complex and surrounding basement","authors":"Enrique Merino-Martínez ,&nbsp;Ezequiel Ferreira ,&nbsp;Pablo Valverde-Vaquero ,&nbsp;José Feliciano Rodrigues ,&nbsp;Javier Escuder-Viruete ,&nbsp;José Luis García-Lobón ,&nbsp;Aratz Beranoaguirre ,&nbsp;María del Carmen Feria ,&nbsp;Carmen Rey-Moral ,&nbsp;Paulo Bravo Silva ,&nbsp;Pablo González-Cuadra ,&nbsp;João Carlos Sousa ,&nbsp;Julián Potti ,&nbsp;Jaime Máximo ,&nbsp;Miguel Gutiérrez-Medina ,&nbsp;Juan Carlos Gumiel ,&nbsp;Gustavo Galán ,&nbsp;Tania Mochales ,&nbsp;José Manuel ,&nbsp;Domingos Cordeiro ,&nbsp;Carmen Galindo","doi":"10.1016/j.precamres.2025.107937","DOIUrl":"10.1016/j.precamres.2025.107937","url":null,"abstract":"<div><div>The southwestern Angolan Shield hosts the Earth’s largest Mesoproterozoic massif-type anorthosite complex (up to 53,500 km²), the Kunene Complex (KC). This complex is the result of a long-lived (∼200 Ma) episodic emplacement of coalescent magmatic pulses. The recent acquisition of multidisciplinary data during the PLANAGEO project has significantly enhanced our understanding of the Precambrian crustal framework from the southwestern Angolan Shield. Combined multi-isotope, structural and geophysical data reveals distinctive crustal zones in the southwestern Angolan Shield that clearly influenced KC’s emplacement within a back-arc setting. The spatio-temporal arrangement of KC pulses suggests westwards magma migration within a complex contractional regime involving large strike-slip systems. A long-lasting and extensive accretionary orogen was responsible for the tectono-thermal activity recorded during most of the Mesoproterozoic. Crustal thinning and partial melting of isotopically heterogeneous lower-crustal sources through mantle upwelling promoted the episodic felsic magmatism contemporaneous with the KC. Crustal contamination processes are evident in gabbro-anorthosites, indicating mantle metasomatism and interaction with wall-rocks and granite melts during ascent, upwelled by lateral-driven forces. Deposition of extensive metasedimentary sequences (&lt;1.26 Ga) covering the KC, along with 1.23–1.07 Ga sublithospheric and mantle-derived magmatism, indicate a shift from a compressional to an extensional regime during late-Mesoproterozoic times. Regional correlations with other Mesoproterozoic units in African and Brazilian counterparts suggest a shared geological evolution, despite potential differences in tectonic setting. These findings supports a refined geological model for the Mesoproterozoic evolution of the southwestern part of the Congo Craton.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"431 ","pages":"Article 107937"},"PeriodicalIF":3.2,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145327169","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":"Understanding Ferruginous Versus Euxinic Conditions by Simulating Microbial Conditions in Meromictic Lakes","authors":"Vanessa M. Hawkins,&nbsp;Cody S. Sheik,&nbsp;Sergei Katsev","doi":"10.1111/gbi.70037","DOIUrl":"https://doi.org/10.1111/gbi.70037","url":null,"abstract":"<p>Ferruginous (iron-rich) conditions have been prominent in oceans throughout the Earth's geologic history but now are reliably found only in a handful of permanently stratified lakes. Microbially mediated iron reduction in such anoxic environments competes with sulfate reduction, which promotes euxinic (sulfide-rich) conditions. Besides the shared demand for organic compounds, the competition is fostered by the produced hydrogen sulfide, which may reduce iron oxides abiotically or co-precipitate with dissolved iron as iron sulfides. Understanding why some environments develop ferruginous rather than euxinic conditions (or vice versa), as well as the attendant effects on methanogenic fermentation, is key to understanding both modern and ancient anoxic ecosystems. Here, we reproduce biogeochemical distributions in multiple anoxic, low-sulfate, meromictic lakes around the world using a biomass-explicit reaction-transport model with a fixed set of metabolism-specific microbial parameters. The results suggest that sulfate reduction and methanogenesis are ubiquitous even in iron-rich systems, and are reflected in microbial surveys. Ferruginous conditions typically develop for surface sulfate concentrations below ≃100 μM. Interestingly, there seems to be a dearth of stably stratified water bodies where sulfate concentrations can persist in the medium-sulfate range of several hundred μM. Rather, when sulfur burial into the sediments becomes iron limited, sulfate tends to accumulate in the water column to much higher (mM) concentrations. A similar mechanism could be suggested to have operated in the variably sulfidic and ferruginous water columns of early oceans. Model simulations also reveal the previously underappreciated role of physical transport in shaping biogeochemical distributions, as minor variations in mixing rates can lead to large variations in microbial abundances. Model applicability across multiple lakes points to an encouraging possibility that geochemical patterns in complex biogeochemical systems may be described from a small number of thermodynamic and kinetic principles using a minimum of fitting parameters.</p>","PeriodicalId":173,"journal":{"name":"Geobiology","volume":"23 5","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gbi.70037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145317800","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":"An Investigation of Dust Activities in Southwest Baluchestan, Iran, by Synergistic use of Handheld Sunphotometer Measurements and CALIPSO-CALIOP Data","authors":"Amir Masoumi,&nbsp;Ruhollah Moradhaseli,&nbsp;Ali Bayat,&nbsp;Farhad Narouie,&nbsp;Ali Akbari","doi":"10.1007/s13143-025-00417-4","DOIUrl":"10.1007/s13143-025-00417-4","url":null,"abstract":"<div><p>The atmospheric aerosol properties near Iranshahr City in Southwest Baluchestan, Iran, were investigated using handheld Calitoo sunphotometer measurements, space-borne CALIPSO-CALIOP lidar recordings, and synoptic station data. The findings indicate the prevalence of dust aerosols throughout the year, with a pronounced presence during the summer season. The aerosol optical depth (AOD), as determined by Calitoo measurements at 540 nm between April and October 2022, peaked in July with a monthly-mean value of 0.61 ± 0.14. During this month, the Angstrom exponent reached 0.43 ± 0.19, providing further evidence of severe dust storm activities in the region. An analysis of the level 2 aerosol profile data obtained from CALIOP measurements during 2006-2023 has been presented. The monthly-averaged AOD at 532 nm obtained from CALIOP data has a bell-shaped distribution with a peak in July (0.92 ± 0.39). These results are in agreement with those measured by Calitoo. The vertical profile of the particulate depolarization ratio (PDR) at 532 nm confirms the dominance of dust at all altitudes. Moreover, the extinction coefficient spike near the surface explains why horizontal visibility decreases during dust events. Consistent with previous studies, our findings identify the dry bed of Hamun Lakes as the primary dust source for the Baluchestan region. Additionally, the dry bed of the Jazmurian ephemeral lake and parts of the Lut Desert appear to be other major dust sources, particularly affecting the western parts of Baluchestan, Iran. These latter sources should be studied in more detail.</p></div>","PeriodicalId":8556,"journal":{"name":"Asia-Pacific Journal of Atmospheric Sciences","volume":"61 4","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145316436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 Significant Role of the Mafic Lower Crust in the Chemical Diversity of Arc Magmas","authors":"Masao Ban,&nbsp;Jun-Ichi Kimura,&nbsp;Toshiro Takahashi,&nbsp;Yuka Hirahara,&nbsp;Tsukasa Ohba,&nbsp;Akihiko Fujinawa,&nbsp;Shintaro Hayashi,&nbsp;Takeyoshi Yoshida,&nbsp;Takashi Miyazaki,&nbsp;Nobutaka Tsuchiya,&nbsp;Shin-ichi Kagashima,&nbsp;Qing Chang,&nbsp;Ryoko Senda,&nbsp;Bogdan Stefanov Vaglarov,&nbsp;Yoshiyuki Tatsumi","doi":"10.1111/iar.70033","DOIUrl":"https://doi.org/10.1111/iar.70033","url":null,"abstract":"<p>The origin of extremely diverse arc magmas erupted along the 600-km-long Quaternary frontal arc of NE Japan was examined using Sr–Nd–Hf–Pb isotopic and major/trace elemental compositions. The major/trace element chemistry of the magmas varied with the various combinations of low-K to medium-K and calc-alkaline to tholeiitic rock suites, even within a single volcano. Nevertheless, magmas from individual volcanoes showed quasi-linear isotopic variations in the Pb–Pb and Nd–Pb isotope spaces irrespective of their complex rock suites. The isotope data indicate a binary mixing origin of the magmas derived from a mostly homogeneous mantle source and the others from an isotopically diverse crust represented by Cretaceous to Paleogene basement granitoids. Assimilation-fractional-crystallization (AFC) and melting-assimilation-storage-hybridization (MASH) processes formed the tholeiitic and calc-alkaline series, respectively. These would have occurred in the amphibolitic lower crust that constitutes the roots of the basement granitoids. This study demonstrates that the mafic lower crust extensively contributes to the chemical diversity of arc magmas, even for relatively undifferentiated basaltic andesites.</p>","PeriodicalId":14791,"journal":{"name":"Island Arc","volume":"34 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/iar.70033","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145317489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Hydrogen and carbon isotopes of plant leaf wax n-alkanes over the entire Loess Plateau of China: Implications for paloehydroclimatic reconstructions","authors":"Jinzhao Liu ,&nbsp;Dongna Yan ,&nbsp;Jiaju Zhao ,&nbsp;Yuan Yao ,&nbsp;Changfeng Sun ,&nbsp;Yunning Cao ,&nbsp;Zhisheng An","doi":"10.1016/j.palaeo.2025.113358","DOIUrl":"10.1016/j.palaeo.2025.113358","url":null,"abstract":"<div><div>Leaf wax <em>n</em>-alkanes have been widely used to indicate past changes of hydroclimates. However, the responses of hydrogen (δ²H_wax) and carbon isotopes (δ¹³C_wax) of leaf wax <em>n</em>-alkanes to hydroclimates still remain unclear. In this study, we systematically investigated leaf wax <em>n</em>-alkane compounds such as <em>n</em>-alkanes, δ²H_wax, and δ¹³C_wax values in modern plants throughout the spatial Chinese Loess Plateau (CLP; ∼ 640, 000 km²) across different seasons (spring, summer, autumn), and analyzed the relationships between δ²H_wax and δ¹³C_wax values and hydroclimatic factors. Our results showed that, over the regional-scale CLP, the effects of plant types on leaf wax <em>n</em>-alkanes were prominent, but the seasonal differences became muted. These finding indicates that plant type effects should be considered, but seasonal variations might be ignored, when leaf wax <em>n</em>-alkanes were used to reconstruct paleohydroclimates on the CLP. Additionally, the isotopic apparent fractionations (ε_app values for δ²H_wax; ε_wax/bulk values for δ¹³C_wax) also showed consistent plant type effects, highlighting differences of ε_app values between dicots and monocots and discrepancies of ε_wax/bulk values between C₃ and C₄ plants. Considering plant type effects, δ²H_wax and δ¹³C_wax values from the CLP were consistent with expectations from the global contexts, and they well responded to hydroclimatic factors (temperature and precipitation). The δ²H_wax values in both dicots and monocots likely responded mainly to temperature, but δ¹³C_wax values in C₃ plants primarily reflected precipitation whereas δ¹³C_wax values in C₄ plants primarily reflected temperature. These findings indicate that δ²H_wax and δ¹³C_wax values have great potentials as proxies for paleotemperature and paleoprecipitation on the CLP and globally.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"680 ","pages":"Article 113358"},"PeriodicalIF":2.7,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145327115","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":"Investigating the different roles of urban environment in long- and short-distance outdoor jogging: Evidence from Shanghai, China","authors":"Ziran Ye ,&nbsp;Xinyue Gu","doi":"10.1016/j.apgeog.2025.103811","DOIUrl":"10.1016/j.apgeog.2025.103811","url":null,"abstract":"<div><div>Urban environments play a crucial role in shaping physical activity behaviors, with outdoor jogging being one of the most accessible and popular forms of exercise. However, most existing studies focus on modeling all jogging in aggregate rather than differentiating between short- and long-distance jogging, despite their distinct spatial and environmental demands. Hence, this study explores the impact of urban environmental factors on both short- and long-distance outdoor jogging in Shanghai, China. Using advanced spatial machine learning techniques, the effects of various urban features, such as density, accessibility and visual perception on jogging intensity are examined. Our findings reveal that road density and housing prices are the most consistent and influential factors. Short-distance jogging is more influenced by proximity to transport hubs, while long-distance jogging is more related to access to open space. Perceptual variables significantly promote jogging intensity when exceeding a certain threshold. Additionally, short-distance jogging is promoted in more mixed-use and central neighborhoods while long-distance jogging is converse. The study contributes to the understanding of urban health dynamics and offers insights into urban planning strategies that encourage outdoor physical activity and promote healthier lifestyles.</div></div>","PeriodicalId":48396,"journal":{"name":"Applied Geography","volume":"186 ","pages":"Article 103811"},"PeriodicalIF":5.4,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145323217","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}