Global and Planetary Change最新文献

{"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":"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":"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":"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}

{"title":"Oceanic deoxygenation linked to enhanced water column stratification in the eastern Tethys during Cretaceous Oceanic Anoxic Event 2","authors":"Yu Liang ,&nbsp;Yong-Xiang Li ,&nbsp;Hongxuan Lu ,&nbsp;Huanye Wang ,&nbsp;Cece Wang ,&nbsp;Cheng Quan ,&nbsp;Weiguo Liu ,&nbsp;Mei-Fu Zhou ,&nbsp;Zhonghui Liu","doi":"10.1016/j.gloplacha.2025.105270","DOIUrl":"10.1016/j.gloplacha.2025.105270","url":null,"abstract":"<div><div>The mid-Cretaceous Oceanic Anoxic Event 2 (OAE2, ∼94 Ma) stands as a prominent deep-time analogue for understanding global oceanic redox variations in response to major environmental perturbations. However, the mechanisms driving oceanic redox evolution in the eastern Tethys during OAE2, particularly the influence of water column stratification, remain poorly investigated. In this study, we analyze the connections between oceanic redox, stratification, and productivity changes in the eastern Tethys during OAE2 using biomarker records of glycerol dialkyl glycerol tetraethers (GDGTs) and <em>n</em>-alkanes from the Gongzha section, southern Tibet. Our results reveal pronounced increases in oceanic deoxygenation and stratification, alongside reduced productivity, through the carbon isotope stage C4, the main phase of OAE2 following the initial perturbation and prior to the recovery. Combining these findings with existing geological data from the Gongzha section, we infer that enhanced water column stratification may have driven the oceanic deoxygenation by diminishing ocean-atmosphere exchange in the eastern Tethys during OAE2. This mechanism differs from that previously observed in the circum-proto-North Atlantic, where increased productivity and associated enhancement in the organic remineralization may have triggered the marine anoxia. By providing biological constraints, our study indicates the dominant role of water column structure in shaping redox evolution in the eastern Tethys, highlighting distinct regional controls on oceanic redox evolution during OAE2.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"258 ","pages":"Article 105270"},"PeriodicalIF":4.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145895084","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":"Precession-dominated summer insolation forcing of East Asian monsoon precipitation since 1.2 Ma: Insights from the Weihe Basin, Central China","authors":"Xuke He ,&nbsp;Yougui Song ,&nbsp;Yue Li ,&nbsp;Jianhong Xu ,&nbsp;Xiaofen Fu ,&nbsp;Huifang Liu ,&nbsp;Qingliang Wang ,&nbsp;Yixiao Han","doi":"10.1016/j.gloplacha.2026.105281","DOIUrl":"10.1016/j.gloplacha.2026.105281","url":null,"abstract":"<div><div>The Asian monsoon is crucial for sustaining billions of people, yet its geological history, primary drivers, and mechanisms remain contentious. To explore the potential driving mechanisms of East Asian summer monsoon (EASM) precipitation since the Early Pleistocene, we here present data from a 272-m-long core of Quaternary lacustrine–fluvial–aeolian sediments from the Weihe Basin in central China. The chronology of the core is established through magnetostratigraphy and tie-point matching with speleothem oxygen isotope (δ¹⁸O) curves. Lithofacies and geochemical profiles reveal that the core records a sedimentary succession from lacustrine through fluvial to aeolian depositional environments since 1.18 Ma. End-member (EM) modeling of lacustrine deposits shows that the transport and deposition of coarse EM3, EM4, and EM5 components are linked to vigorous nearshore hydrodynamics. Consequently, the summed proportion of these three EMs serves as an indicator of monsoon-induced paleolake transgressions and regressions. Reduced precipitation causes lake contraction, and the development of littoral lake sub-facies enriched in coarse EM components. Hydrodynamic sorting, modulated by catchment hydrology, imparted a precession signal to lacustrine bulk-sediment XRF element intensities. On orbital timescales, EASM precipitation variations are governed by precession-dominated boreal-summer insolation. Featuring a robust chronology and sensitive response of lacustrine proxies to precipitation, our findings confirm that insolation forcing fundamentally governs precipitation patterns in East Asia.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"258 ","pages":"Article 105281"},"PeriodicalIF":4.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145895046","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":"Astronomically paced Katian (late Ordovician) sea-level changes: A record from Northern Yangtze Block","authors":"Chuanzhen Ren ,&nbsp;Qiang Fang ,&nbsp;Huaichun Wu ,&nbsp;Wentao Huang ,&nbsp;Xiuchun Jing ,&nbsp;Jinlin Liu ,&nbsp;Ziyu Wang ,&nbsp;Congcong Gai ,&nbsp;Meinan Shi ,&nbsp;Tianshui Yang ,&nbsp;Haiyan Li","doi":"10.1016/j.gloplacha.2026.105283","DOIUrl":"10.1016/j.gloplacha.2026.105283","url":null,"abstract":"<div><div>Astronomical forcing is recognized as a significant external driver influencing sea-level changes under both typical icehouse and greenhouse conditions; however, mechanisms underlying this forcing remain ambiguous in the context of such climatic transition. The Katian represents a key stage characterized by a gradual shift from Sandbian greenhouse to Hirnantian icehouse conditions in late Ordovician. Here, we conducted sedimentological and cyclostratigraphic analyses on the Katian Shiyanhe Formation at Sigang section in the Northern Yangtze Block, aiming to elucidate the forcing mechanisms of sedimentary processes during a period of climatic transition. Five microfacies zones comprising eight microfacies were identified, and these collectively indicate a mixed shelf sedimentary environment in which three third-order and nine fourth-order depositional sequences were developed. Cyclostratigraphic analyses of magnetic susceptibility (MS), calcium (Ca), and lithological rank series reveal robust Milanković cycle signals, including 405-kyr long eccentricity, 91–106-kyr short eccentricity, 32.4–33.4-kyr obliquity, and 17.5–21.6-kyr precession cycles. A newly constructed astronomical time scale calibrates the duration of third- and fourth-order depositional sequences as ∼1.2 Myr and ∼405 kyr, respectively corresponding to the long-period obliquity and long eccentricity cycles. The cause-and-effect relationship between these cycles and sea-level changes was further corroborated through the sedimentary noise modeling of MS and Ca data. In addition, a pronounced imprint of the obliquity cycle is evident in the middle <em>Aphelognathus grandis</em> conodont biozone (viz., 448.5–449.7 Ma). This interval coincides with sea-level fall and the reported ice sheet growth at Gondwana, indicative of an enhanced teleconnection between the low and high latitudes driven by global cooling. Our study highlights the controlling effects of different astronomical cycles on the sedimentary processes during the climatic transition of stepwise cooling.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"258 ","pages":"Article 105283"},"PeriodicalIF":4.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145902926","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}