Global and Planetary Change最新文献

{"title":"Persistence and resilience on Mount Etna's active flank: An integrated geological and archaeological perspective","authors":"Carla Bottari ,&nbsp;Alessandro Luppino ,&nbsp;Salvatore Claudio Alparone ,&nbsp;Francesca Forni ,&nbsp;Gianluca Groppelli ,&nbsp;Mimmo Palano ,&nbsp;Francesco Sortino ,&nbsp;Salvatore Giammanco","doi":"10.1016/j.gloplacha.2026.105327","DOIUrl":"10.1016/j.gloplacha.2026.105327","url":null,"abstract":"<div><div>Volcanic environments illustrate how human communities have learned to persist within dynamic, hazardous landscapes by balancing risk and opportunity. Mount Etna (Sicily, Italy) – one of the world's most active volcanoes – provides an outstanding natural laboratory to investigate the interplay between geodynamic and volcanic processes as well as human adaptation. The site of Santa Venera al Pozzo (SVP) exemplifies this duality: archaeological and geological evidence reveal a persistent human presence since the Late Neolithic, sustained by fault-controlled hydrothermal discharge and a geomorphological position that ensured long-term stability outside major lava flow pathways.</div><div>This study integrates geological, geochemical, geodetic, seismological, and archaeological data to examine how tectonic and magmatic processes sustained hydrothermal activity and supported enduring settlement. Results indicate that (i) deformation was largely accommodated by creeping faults, in turn enhancing permeability and maintaining spring discharge; (ii) the site's distal position from eruptive rift zones provided geomorphological stability; and (iii) cultural practices promoted the adaptive reuse of geothermal resources over the time.</div><div>The case of SVP demonstrates that the same Earth processes generating hazards also maintain vital resources, enabling long-term human resilience. This integrated geological–archaeological perspective provides a transferable framework for understanding sustainability and risk in volcanically active regions worldwide.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"259 ","pages":"Article 105327"},"PeriodicalIF":4.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146048396","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}

{"title":"Late Cenozoic transtensional deformation along the Chenghai fault zone and its constraint on micro-block clockwise rotation in the southeastern Tibetan Plateau","authors":"Xiaolong Huang ,&nbsp;Zhichao Li ,&nbsp;Zhonghai Wu ,&nbsp;Xiaojin Huang ,&nbsp;Kungang Wu ,&nbsp;Feipeng Huang","doi":"10.1016/j.gloplacha.2026.105320","DOIUrl":"10.1016/j.gloplacha.2026.105320","url":null,"abstract":"<div><div>The Chenghai fault zone is a crucial component of the Dali fault system, essential for understanding Cenozoic crustal deformation along the southeastern Tibetan Plateau. This study involved detailed remote sensing and field mapping to examine the geometry and kinematics of the fault zone, with the purpose of analyzing the late Cenozoic deformation in the study area. Findings reveal that the Chenghai fault zone extends for 200 km from Jinguan to the southern end of the eastern Midu Basin, where it intersects and follows the trace of the Red River Fault. The Chenghai fault zone has left-lateral, normal-slip kinematics, with the normal-slip component being pronounced along most fault segments. The transtensional slip likely began in the early Pliocene (ca. 7 Ma) based on the analysis of thermochronology data and the sedimentary age of the Sanying Formation. The maximum dip- and left-slip rates are about 0.2–0.3 mm/yr and 0.8–0.9 mm/yr, respectively, since. ca. 7 Ma. Through the analysis of the geometry, kinematics, and seismic activity of the Chenghai fault zone, the study concludes that the Chenghai fault zone exhibits significant rotation, which can be attributed to the clockwise rotation of the Dali fault system. Combined geodetic velocity profiles, we infer that the deformation of the Dali fault system is primarily influenced by the non-uniform rotation of the southeastern Tibetan Plateau. To the west of the Dali fault system, clockwise rotation remains uninterrupted, whereas to the east, material extrusion between the Dali fault system and the Xianshuihe-Xiajiang fault zone is inhibited by the Red River fault zone. The left-lateral motion along the Chenghai fault zone is predominantly governed by clockwise rotation, while the normal faulting is chiefly controlled by differential rotation. Consequently, we infer that the Dali rift system is a manifestation of differential rotation along the southeastern margin of the Tibetan Plateau. By comparing it with the Pamir Plateau and the Aegean Sea region, we propose that pre-existing structures and block rotation are crucial mechanisms driving lateral deformation in the peripheral zones of continent-continent collision orogens.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"259 ","pages":"Article 105320"},"PeriodicalIF":4.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146015048","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}

{"title":"Holocene relative sea-level changes from the Atlantic coasts of South America","authors":"K. Rubio-Sandoval ,&nbsp;T.A. Shaw ,&nbsp;M. Vacchi ,&nbsp;N. Khan ,&nbsp;B.P. Horton ,&nbsp;J.R. Angulo ,&nbsp;M. Pappalardo ,&nbsp;A.L. Ferreira-Júnior ,&nbsp;S. Richiano ,&nbsp;M.C. de Souza ,&nbsp;P.C. Giannini ,&nbsp;D.D. Ryan ,&nbsp;E.J. Gowan ,&nbsp;A. Rovere","doi":"10.1016/j.gloplacha.2026.105315","DOIUrl":"10.1016/j.gloplacha.2026.105315","url":null,"abstract":"<div><div>Holocene relative sea-level (RSL) changes along the Atlantic coast of South America reflect a complex interplay between ice equivalent sea-level, glacio-isostatic adjustment (GIA), regional tectonics, and local sedimentary processes. However, the uneven spatial and temporal resolution of existing Holocene RSL data has hindered regional assessments. Here, we compile and standardize 1108 RSL data points from Brazil, Uruguay, Argentina, and Chilean Tierra del Fuego, creating the first comprehensive database for the southwestern Atlantic. The data reveals a widespread Mid-Holocene highstand between 7000 and 4000 years BP, with RSL rising 2 to 4 m above present-day sea level, followed by a gradual fall to present. This pattern is consistent with GIA model predictions across the region's &gt; 50° latitudinal span. Peak rates of RSL change occurred during the Early to Mid-Holocene transition, reaching up to 17.2 mm/yr in Tierra del Fuego and decreasing to 1.6 mm/yr near the Amazon delta. After 5000 years cal BP, RSL started to fall at 0.5 mm/yr. This Atlantic coast of South America database fills a critical geographic gap and provides a robust framework for refining GIA models and understanding sea-level evolution during the Holocene in the Southern Hemisphere.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"259 ","pages":"Article 105315"},"PeriodicalIF":4.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995747","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}

{"title":"Active faulting and crustal deformation along the East Sunda-Banda Arc: Implications for Regional Geohazards","authors":"Xiaodong Yang ,&nbsp;Xiwu Luan ,&nbsp;Liangyu Zhu ,&nbsp;Xinze Han ,&nbsp;Zhiwen Zhang ,&nbsp;Zhiyuan Zhou ,&nbsp;Jian Lin ,&nbsp;Liming Wang","doi":"10.1016/j.gloplacha.2026.105326","DOIUrl":"10.1016/j.gloplacha.2026.105326","url":null,"abstract":"<div><div>The east Sunda-Banda Arc is among the most tectonically active regions in southeast Asia. However, most instrumental major earthquakes (M_W ≥ 6.6) have occurred along the Flores-Wetar thrust (FWT) in the backarc, while few such events have occurred in the Java trench and Timor Trough (TT) in the forearc. The mechanism behind such contrasting earthquake distribution from backarc to forearc remains unclear. Here we integrate new 2D seismic profiles, seismicity and focal mechanisms, GPS velocities and seismic velocity models to study the active faulting, strain partition, earthquake locations and their implications for regional geohazards. Our results show that the FWT and TT slip at rates of 7.6–23.9 mm/yr and 13.3–30.7 mm/yr respectively, accounting for 9.3%–29.2% and 16.3%–37.6% of the convergence between Indo-Australian and Sunda plates. The FWT is seismically more active presently with 12 thrust events (M_W ≥ 6.6) including the largest one of 1992 Flores M_W 7.9, while the TT seems to be less active as it is absent of thrust events (M_W ≥ 6.6) and lacks seafloor thrusting. However, the short observational period (since 1900) cannot rule out a possible longer earthquake recurrence along TT. A variable strain rate is observed along FWT where the highest value (&gt;200 nanostrain/yr) is coincident with the 1992 M_W 7.9 location may represent a transient feature which will decay with time. By integrating the strain rate with earthquake and rupture locations, we propose two seismic gaps along FWT, which combined with distinct seafloor FWT scarps at places reveals a significant seismic and tsunami threat.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"259 ","pages":"Article 105326"},"PeriodicalIF":4.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033662","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}

{"title":"Tropicalization and biodiversity restructuring of calcifying plankton in a rapidly warming Mediterranean Sea","authors":"Arturo Lucas ,&nbsp;Sven Pallacks ,&nbsp;Alessandro Incarbona ,&nbsp;P. Graham Mortyn ,&nbsp;Patrizia Ziveri","doi":"10.1016/j.gloplacha.2026.105314","DOIUrl":"10.1016/j.gloplacha.2026.105314","url":null,"abstract":"<div><div>Climate-driven shifts in species diversity, community composition and phenology can disrupt ecosystem functioning and compromise marine ecosystem stability. The Mediterranean Sea, a global biodiversity hotspot, is particularly vulnerable to anthropogenic climate change and is experiencing a growing biodiversity crisis especially driven by warming, habitat degradation, pollution and the introduction of new species. Yet, current knowledge of biodiversity changes in this region is largely limited to shallow shelf benthic communities and macroorganisms. Calcifying phytoplankton and zooplankton, however, offer a unique lens into pelagic ecosystem dynamics, as their fossil record preserves signals of biodiversity change in deep-sea sediments spanning the Industrial Era and the current phase of rapid warming. This study focuses on the reconstruction of diversity change of two dominant calcifying plankton groups: coccolithophores and foraminifera (primary and secondary producers). We examine two selected sedimentary records of the western and central Mediterranean—Alboran Sea and the Strait of Sicily—spanning the last ∼1700 and 200 years of modern climate, respectively. By quantifying abundance, diversity and turnover of species composition we evaluate the potential response of calcifying plankton assemblages to oceanographic changes under anthropogenic climate change. The results revealed contrasting changes in the diversity of the two dominant calcifying plankton groups, with a rapid increase in coccolithophore diversity alongside a decrease in planktonic foraminiferal diversity during the Industrial Era. We attribute these group-specific responses to ecological and physiological differences, particularly in relation to life cycles and water column distribution, under increasingly stratified, nutrient-depleted surface waters driven by rising sea surface temperatures. In addition, this study provides first indication of tropicalization of the western Mediterranean plankton derived from the increasing intrusion and eastward expansion of the coccolithophore <em>Gephyrocapsa oceanica</em> from the Strait of Gibraltar into the Mediterranean Sea. The highest abundances of this species are restricted to the Equatorial Atlantic Divergence Zone and only found in higher proportions in the Mediterranean during past warm periods. Although the temperate-productivity foraminiferal species of <em>Globigerina bulloides</em> and <em>Globorotalia inflata</em> remain the dominant foraminiferal species, previous minor dominant species are being replaced by warm-oligotrophic species, such as <em>Trilobatus sacculifer</em> and <em>Globigerinella</em> spp. These align with model projections of tropical species migrating into the area, previously documented among benthic organisms and point to a broader restructuring of planktonic life.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"259 ","pages":"Article 105314"},"PeriodicalIF":4.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995746","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}

{"title":"Early Pliocene (Zanclean) sea surface temperature for PlioMIP3","authors":"Harry J. Dowsett,&nbsp;Kevin M. Foley","doi":"10.1016/j.gloplacha.2026.105293","DOIUrl":"10.1016/j.gloplacha.2026.105293","url":null,"abstract":"<div><div>Paleoclimate researchers have been comparing Pliocene environmental data to paleoclimate model results since the 1980s. The Pliocene Model Intercomparison Project (PlioMIP) began in 2008 with a focus on the Late Pliocene. Here we assess the availability and utility of sea surface temperature (SST) data for verification of Pliocene Model Intercomparison Project (PlioMIP3) Early Pliocene (Zanclean) experiments. We analyze published data in terms of quantity and spatial distribution. Only SST estimates derived using alkenone paleo thermometry are reported, and all estimates are based upon the same temperature calibration. Sea surface temperature data are selected from within three distinct time intervals: The early Zanclean 5.3 Ma – 4.2 Ma time slab, and two time slices within the early Zanclean, chosen by PlioMIP3 at 4.870 Ma and 4.474 Ma. Results show the early Zanclean time slab contains 2055 individual estimates. Approximately ∼ 80% of these estimates come from Sites 609, 642, 846, 847, 882, 907, and 1146. There are 17 sites with a total of 42 estimates within the 4.474 Ma ±10 kyr time slice, and 15 sites with a total of 47 data points within the 4.870 Ma ±10 kyr interval. The sparse spatial and temporal distribution of Zanclean data, relative to the data available for the mid Piacenzian, makes point-by-point data model comparison suspect. We suggest interpreting model output against lower resolution long term trends in proxy data, and comparison of models through temperature gradients, may be the most useful application of currently available data. Integrating Zanclean age coastal plain sequences within data model comparison schemes, for increased understanding of regional climate impacts, also holds great potential.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"259 ","pages":"Article 105293"},"PeriodicalIF":4.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995745","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}

{"title":"Multi-scale pattern analysis of permafrost dynamics on the Qinghai–Tibet Plateau based on machine-learning reconstruction","authors":"Peng Jiang ,&nbsp;Kunqi Ding ,&nbsp;Jiaying Ni ,&nbsp;Rongrong Zhang ,&nbsp;Peng Shi ,&nbsp;Qin Ju ,&nbsp;Bin Yang ,&nbsp;Zhongbo Yu","doi":"10.1016/j.gloplacha.2026.105341","DOIUrl":"10.1016/j.gloplacha.2026.105341","url":null,"abstract":"<div><div>The accelerating degradation of permafrost on the Qinghai–Tibet Plateau (QTP) is a critical driver of regional and global climate change. However, conventional models often limit our understanding by overlooking thermal memory and failing to deconstruct complex spatial dynamics. This study introduces a novel diagnostic framework that pairs a thermal-memory-aware machine learning model with a multi-scale spatiotemporal analysis system to overcome these limitations. Our reconstruction from 1960 to 2020 reveals that the total permafrost area shrank by approximately 16% from its peak, while the mean active layer thickness (ALT) deepened, with degradation accelerating sharply after the 1980s. Vertically, we identify a systematic misalignment between the elevation of maximum permafrost stability (peak area) and maximum thermal sensitivity (peak ALT), the magnitude of which serves as a robust indicator of basin-scale vulnerability. Horizontally, we reveal a critical spatiotemporal mismatch: the geometric centroid of the permafrost area remains relatively stable, while its thermal center of mass exhibits large, volatile oscillations. This decoupling is driven by the contrast between rapid degradation at the warm, wet margins and the anchoring effect of the vast thermal inertia in the cold, arid core. Ultimately, our study reveals that permafrost degradation is a complex, multi-scale process rather than a uniform retreat. The diagnostic framework and the identified spatiotemporal decoupling provide a new perspective for assessing the stability and vulnerability of cryospheric systems in a warming world.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"259 ","pages":"Article 105341"},"PeriodicalIF":4.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072729","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}

{"title":"Two-dimensional lithospheric electrical structure and implications for the geodynamic process of the Western Kunlun Orogen","authors":"Munirdin Tohti ,&nbsp;Wenjiao Xiao ,&nbsp;Qigui Mao ,&nbsp;Miao Sang ,&nbsp;Zhiguo An ,&nbsp;Qingyun Di ,&nbsp;Yibo Wang ,&nbsp;Liang Zhao","doi":"10.1016/j.gloplacha.2025.105265","DOIUrl":"10.1016/j.gloplacha.2025.105265","url":null,"abstract":"<div><div>The Western Kunlun Orogen (WKO), located on the northwestern margin of the Tibetan Plateau, is considered as an accretionary orogen that preserves the entire tectonic evolution of the Tethyan oceans. Its Paleozoic to early Mesozoic orogenic history is crucial for reconstructing the Paleo-Asian plate, as it occupies a key tectonic position at the junction of the Pan-Asian and Tethyan tectonic domains. However, considerable dispute exists regarding its long-term orogenic process, particularly concerning the closure timings, positions, and subduction polarity of the Proto -Tethys and Paleo-Tethys Ocean in the WKO. The main cause of these controversies is the lack of a high-resolution lithospheric structure in this area. To clarify and gain deeper insights into the orogenic processes of Tethys, a 350-km-long Magnetotelluric (MT) profile, consisting of 32 broadband sounding stations, was deployed across the Tarim Basin (TB), Northern Kunlun Terrane (NKT), Southern Kunlun Terrane (SKT), Mazar Accretionary prism, and Karakorum Terrane (KKT) to collect field data for at least 36 h. Dimensionality analysis indicated that a 2D analysis was valid. The MT data were rotated to a 150° direction before inversion, based on an electrical principal strike analysis. The MT data were then imaged through a joint inversion of Transverse Electric Field (TE) and Transverse Magnetic Field (TM) modes using a nonlinear conjugate gradient (NLCG) algorithm. The resulting model provides crucial new constraints on the lithospheric structure beneath the WKO, revealing several distinct resistive anomalies. The bidirectional dipping geometry of these anomalies, integrated with geochronological and geochemical evidence, reveals two distinct subduction systems: one between the Northern and Southern Kunlun terranes, representing the subduction polarity of Proto-Tethys Ocean, and another between the Southern Kunlun and Karakorum terranes, recording the subduction process of Paleo-Tethys Ocean. Additionally, we interpret two resistive lower crust-uppermost mantle structures beneath the Mazar accretionary prism as a delaminated oceanic slab. Concurrently, a large, interconnected high-conductivity zone from the crust to the upper mantle is identified, likely reflecting partial melting due to asthenospheric upwelling triggered by Mid-Jurassic slab delamination. Furthermore, we propose that these pre-existing weak zones ultimately facilitated the Cenozoic deformation and uplift of the Kunlun Mountains during the ongoing India-Asia collision.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"258 ","pages":"Article 105265"},"PeriodicalIF":4.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145785308","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}

{"title":"Geochemical and isotopic insights into uranium mineralization in the Dongsheng Area (Ordos Basin, NW China): Implications for global uranium systems","authors":"Shamim Akhtar ,&nbsp;Tehseen Zafar ,&nbsp;Xiaoyong Yang ,&nbsp;Fabrizio Frontalini","doi":"10.1016/j.gloplacha.2026.105313","DOIUrl":"10.1016/j.gloplacha.2026.105313","url":null,"abstract":"<div><div>The Dongsheng region of the Ordos Basin (China) contains important sandstone-hosted uranium deposits that reveal an evolving interaction of geochemical evolution and tectono-sedimentary dynamics. The present work combines whole-rock and carbon‑sulfur isotopic compositions to understand the origin and formation of uranium metallogeny within the Middle Jurassic intracontinental Zhiluo Formation of the Ordos Basin. The δ¹³C values (−26.7‰ to −2.2‰) of calcite-cement indicate that the carbon mainly originated through biochemical remineralization. Negative and variable δ¹³C values indicate a strong biogenic carbon contribution, while positive excursions reflect mantle or inorganic inputs. Additionally, the δ³⁴S composition (−25.2‰ to 10.2‰) indicates the mutual inputs from bacterial sulfate reduction and Rayleigh fractionation. The broad δ³⁴S range of pyrite similarly points to multiple sources, with a strong bacterial sulfate reduction signal. Trace element patterns show Light Rare Earth Element (LREE) enrichment, Heavy Rare Earth Elements (HREE) depletion, and distinctive “W-shaped” anomalies (e.g., Nd, Nb, Zr), consistent with reductive immobilization under diagenetic conditions. Tectonic reconstruction and sedimentary provenance support a deposition along an active continental margin with felsic to intermediate source rocks. The Zhiluo Formation was deposited in arid to semi-arid settings, as evidenced by low Rb/Sr and high Sr/Cu and Sr/Ba ratios, reflecting high paleosalinity and strong evaporation. A revised genetic model is here proposed in which oxidized uranium-bearing groundwater interacts with both locally derived organic matter and hydrocarbon-charged reducing fluids (e.g., CH₄, CO, H₂S, CO₂) along structurally controlled fluid pathways, resulting in redox-driven uranium precipitation. This integrated isotopic–geochemical framework not only refines the mineralization model for the Dongsheng deposit but also provides a predictive approach for uranium exploration in analogous basinal settings worldwide. Our outcomes stress the wider role of microbial-hydrocarbon cycling in modulating uranium deposits across continental settings.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"258 ","pages":"Article 105313"},"PeriodicalIF":4.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995741","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}

{"title":"Late Ordovician arc-continent collision in the northernmost Tethyan-Ocean: Insights from detrital chromite and garnet geochemistry of the Koumenzi Formation in the Qilian Orogenic Belt","authors":"Hui Chen ,&nbsp;Zhen Yan ,&nbsp;Changlei Fu ,&nbsp;Jonathan C. Aitchison","doi":"10.1016/j.gloplacha.2026.105280","DOIUrl":"10.1016/j.gloplacha.2026.105280","url":null,"abstract":"<div><div>The Qilian Orogen in the northeastern margin of Qinghai-Tibetan plateau records the tectonic history of the Proto-Tethyan Ocean from its initial subduction to final closure. However, the timing of subduction initiation, subduction polarity, and arc-continent collision processes remain controversial. This study investigates detrital heavy mineral assemblages and geochemistry of 135 detrital chromite and garnet grains from nine sandstone samples of the Upper Ordovician Koumenzi Formation in a coastal tidal environment within the North Qilian Belt. The results reveal distinct spatial variations in mineral abundance: chromite is more prevalent in the northern samples compared to central and southern sections, while garnet abundance exhibits an inverse pattern, with the highest abundance observed in the central section. Compositional analyses reveal that the detrital chromites closely resemble those from North Qilian MOR- and forearc SSZ-type ophiolites, whereas garnets display geochemical affinities with high-pressure/low-temperature metamorphic rocks from the accretionary complex and amphibolite–granulite–facies metamorphic complex, suggesting a mixed provenance. Integrated with detrital compositions of sandstone and conglomerate, as well as a multiple flow system characterized by SEE to NEE- and NWW to W-ward currents, these data collectively support a dual source region involving both the North Qilian island arc–accretionary complex (NQIAC) and the Central Qilian Block (CQB). Based on the spatial-temporal evolution of the NQIAC and Andean-type margin of the CQB, we suggest that the Proto-Tethyan Ocean underwent bidirectional subduction between the CQB and the North Qilian island arc from ∼520 to 450 Ma, followed by a subduction polarity reversal during arc-continent collision at ∼450–440 Ma, triggering formation of a retro-foreland basin that received detritus from both the uplifted accretionary complex and the CQB.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"258 ","pages":"Article 105280"},"PeriodicalIF":4.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928707","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}