Global and Planetary Change最新文献

{"title":"Testing Bergmann's rule in marine invertebrates: Using global brachiopod data during the Permian glacial-interglacial transition","authors":"Xiujuan Wu ,&nbsp;Thomas L. Stubbs ,&nbsp;Huiting Wu ,&nbsp;Yang Zhang ,&nbsp;Anfeng Chen ,&nbsp;Hongsong Guo ,&nbsp;Fanshuai Meng","doi":"10.1016/j.gloplacha.2025.104737","DOIUrl":"10.1016/j.gloplacha.2025.104737","url":null,"abstract":"<div><div>Bergmann's rule states that organisms tend to be larger in cold higher latitudinal areas and smaller in warmer lower latitudes, and that this latitudinal gradient of body-size becomes steeper during colder time intervals. Originally formulated for warm-blooded animals, this theory has also been applied to ectotherms. However, few studies have been conducted to examine latitudinal patterns of marine invertebrate body-size, and the idea concerning the latitudinal gradient varying along with overall climate has received little attention. Based on body-size data of 26,112 brachiopods from the Permian glacial-interglacial transition, this paper finds that the latitudinal size distribution of brachiopods followed Bergmann's rule, but the changing pattern of latitudinal gradients along with climate was opposite to that expected in Bergmann's rule.</div><div>Except for several specific regions where trends were affected by paleoequatorial currents or there are limited data, brachiopod body-size generally increased as latitude increased. From the colder early Cisuralian (Asselian–Sakmarian) to the warmer Guadalupian, the latitudinal gradient of brachiopod body-size distinctly increased. The starvation-resistance hypothesis may explain this latitudinal pattern of brachiopod body-size and the variation in latitudinal gradients. In higher latitudinal areas, brachiopods tend to grow to larger size to cope with seasonal fluctuation in resource availability, resulting in higher proportion of brachiopods with large body-size in higher latitudinal areas. During the cold ice age, small individuals, which were more abundant in low latitudinal areas, were more vulnerable to, and heavily affected by, the highly seasonal climates. This resulted in heavier losses of small-sized brachiopods in lower latitudinal areas than in high latitudes, and therefore flatter latitudinal gradient of body-size than warmer periods. During the warmer late Cisuralian (Artinskian-Kungurian) and Guadalupian, more small-sized individuals started to flourish in low latitudinal areas, and cool high latitudinal areas with pronounced seasonality still favored large individuals over small ones. The increased proportion of small-sized individuals in lower latitudes then resulted in the steeper latitudinal gradients of brachiopod body-size in warmer periods. Metabolic rate and oxygen solubility have been used to explain the larger body-size of marine invertebrate in higher latitudes in previous studies, but these are considered to have played a less important role in the latitudinal patterns of body-size in this study, since they do not support the result that the latitudinal gradient became steeper when it got warmer.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"246 ","pages":"Article 104737"},"PeriodicalIF":4.0,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143350555","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":"Insight into the continental lithosphere using 3D geophysical and petrological modelling: An example from the Novohrad-Gemer region (Pannonian Basin, Slovakia-Hungary)","authors":"Jaroslava Pánisová ,&nbsp;Miroslav Bielik ,&nbsp;Monika Huraiová ,&nbsp;Dominika Godová ,&nbsp;Vladimír Bezák ,&nbsp;Patrik Konečný ,&nbsp;Vratislav Hurai","doi":"10.1016/j.gloplacha.2025.104735","DOIUrl":"10.1016/j.gloplacha.2025.104735","url":null,"abstract":"<div><div>Percolation of fluids and melts in the crust and the lithospheric mantle produces alteration zones with significantly disturbed physical properties, such as electrical resistivity and seismic velocity. The geophysical signatures of a metasomatized mantle include gravity responses as well because the modified modal and chemical compositions result in density changes. Here, we show how the local anomalous gravity field can be mapped in intraplate tectonic settings and interpreted using three-dimensional integrated modelling, involving intra-crustal structures, deep faults, and various mantle lithologies. The 3D interpretation performed using IGMAS+ software enables the integration of independent geo-datasets. Densities of near-surface (&lt;5 km) bodies have been defined using laboratory measurements of surface and borehole rock samples and from well-logging. To calculate rock densities at greater depths, p-wave velocities have been transformed to <em>in situ</em> densities (<em>ρ</em>), while the densities of the lower lithosphere have been determined using thermodynamic modelling constrained by the chemical composition of xenoliths brought to the surface by alkali basalts. Thermobarometric data on megacrysts helped constrain the vertical extent of mantle metasomatism. To elucidate the inherent ambiguity of the gravity method, several geologically reasonable models conforming to the observed gravity field are tested. Based on the proposed 3D lithospheric models, the following conclusions can be drawn regarding the northern margin of the Pannonian Basin: a) The thickness of Neogene volcanics and sediments is variable, ranging from 0 to 4 km; b) The Hurbanovo-Diósjenő-Darnó fault zone is a steep and deeply penetrating first-order tectonic zone filled with low-density rocks in the upper crust and characterized by low-amplitude gravity anomalies and a maximum of modified horizontal gradient amplitude; c) Garnet-bearing mafic rocks with a density of 3.1 g⋅cm⁻³ are identified at the Conrad discontinuity; d) The subjacent lithospheric mantle is characterized by a sandwich structure consisting of a 9.0–9.5 km thick upper layer of mafic cumulates, a 12.0 km thick middle layer of the metasomatized mantle, and the wehrlitized mantle in a depth interval from 50 km to 77 km. Alternative models admit either a crustal Cadomian(?) segment with a density of 2.84 g⋅cm⁻³, with its upper boundary ranging from 10 to 18 km located beneath the Veporic unit, or a purely hypothetical eclogite layer with a density of 3.51 g⋅cm⁻³ within the mantle. Such an interdisciplinary approach combining geophysical and petrological data is also applicable in other continental tectonic settings. Detection of crustal and mantle sources related to deep-seated deformation zones through specific geophysical patterns could play an important role in global lithosphere research.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"247 ","pages":"Article 104735"},"PeriodicalIF":4.0,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Nitrogen cycling and marine redox evolution during the Ediacaran–Cambrian transition","authors":"Chao Chang ,&nbsp;Thomas J. Algeo","doi":"10.1016/j.gloplacha.2024.104679","DOIUrl":"10.1016/j.gloplacha.2024.104679","url":null,"abstract":"<div><div>The Cambrian Explosion was an unprecedented bioevolutionary event that witnessed rapid diversification of marine invertebrate phyla and establishment of metazoan-dominated marine ecosystems. Nitrogen is a critical nutrient element essential for all life on Earth, and its biogeochemical cycling in the ocean is tightly associated with marine redox conditions. Numerous nitrogen isotope investigations of the Ediacaran-Cambrian (<em>E</em>-C) transition have been undertaken, but an integrated analysis of contemporaneous nitrogen cycling has not been achieved yet. Here, we compile published nitrogen isotope data for the South China Craton over the interval from ∼550 Ma (late Ediacaran) to ∼514 Ma (late Stage 3 of early Cambrian) with the goals of identifying key changes in the nitrogen cycle and their relationship to marine redox evolution and the Cambrian Explosion. Combined with independent redox proxy data, our δ¹⁵N dataset provides insights into spatio-temporal variation in rates of denitrification and N₂ fixation induced by marine redox fluctuations, which constrains the distribution of suboxic environments and the relative position of the oceanic redoxcline. On this basis, we propose a new model of marine nitrogen-cycle evolution during the E–C transition in which (1) nitrate availability modulated the ecological development and distribution of eukaryotic primary producers, and (2) nitrate-replete ecological niches for eukaryotic primary producers, especially benthic algae expanded significantly during Cambrian Age 3, and (3) increasing biological pump efficiency promoted organic burial and net O₂ release, thus contributing to oceanic oxygenation and the radiation of early animals.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"245 ","pages":"Article 104679"},"PeriodicalIF":4.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142884637","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":"Impact of the 1994–1997 temporary decrease in Northern Hemisphere stratospheric methane on the 1990s methane trend","authors":"Yuanyuan Han ,&nbsp;Shentao Li ,&nbsp;Xinlong Tan ,&nbsp;Wenyan Guo ,&nbsp;Wuhu Feng ,&nbsp;Xin Li ,&nbsp;Feiyang Wang ,&nbsp;Fei Xie","doi":"10.1016/j.gloplacha.2025.104697","DOIUrl":"10.1016/j.gloplacha.2025.104697","url":null,"abstract":"<div><div>Methane (CH₄) ranks as the second most significant anthropogenic greenhouse gas following carbon dioxide (CO₂). It originates from a wide range of surface sources and subsequently enters the stratosphere through the tropical tropopause. In line with the observed positive trend in tropospheric CH₄, stratospheric CH₄ has shown an overall increase in the long-term trend. However, contrary to the continuous increase in tropospheric CH₄, stratospheric CH₄ exhibits a temporal decrease in the Northern Hemisphere middle and upper stratosphere during short-time periods. This study investigates the causes behind the decreasing trend of stratospheric CH₄ in the Northern Hemisphere from 1991 to 2000. We find that the extreme decrease of stratospheric CH₄ from July 1994 to May 1997 contributes to the overall decreasing trend of CH₄ from 1991 to 2000. This extreme decrease is attributed to the weakened meridional component of the residual circulation. The weakened meridional component attenuates the transport of CH₄-rich air from the low-latitude lower stratosphere to the mid-latitude middle and upper stratosphere, leading to the observed decrease in CH₄. It is further found that the smallest SST gradient in the North Pacific and adjacent regions from 1980 to 2020 is identified as a significant factor contributing to the weakened residual circulation and the decrease in CH₄. Simulations by a chemistry-climate model support the results.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"245 ","pages":"Article 104697"},"PeriodicalIF":4.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975632","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":"Alternating dominance of Westerlies and East Asian winter monsoon on dust activities across the northeastern Qinghai-Tibet Plateau since 18.5 ka","authors":"Hao Long ,&nbsp;Yun Cai ,&nbsp;Jingran Zhang ,&nbsp;Liangqing Cheng ,&nbsp;Linhai Yang ,&nbsp;Hongyi Cheng","doi":"10.1016/j.gloplacha.2024.104684","DOIUrl":"10.1016/j.gloplacha.2024.104684","url":null,"abstract":"<div><div>The mid-latitude Westerlies and the East Asian winter monsoon (EAWM) are two major atmospheric circulation systems influencing dust activities in the Northern Hemisphere (NH). However, the interplay between these wind systems and their effects on regional dust activities remain poorly understood. In this study, we present a well-dated aeolian sedimentary sequence from the loess section (ZES) on the southern slope of the Qilian Mountains in the northeastern Qinghai-Tibetan Plateau (NE-QTP). It provides insights into the response of dust activities to these wind systems for the last 18.5 ka. We developed a detailed chronology for ZES section based on luminescence dating of multiple signals from 29 samples (yielding a total of 87 ages). The luminescence sensitivities and element analysis of the sediments indicate a shift in dust source around 7.5 ka, contributed to a transition in the atmospheric circulation controls of the NE-QTP. Specially, our findings suggest that dust activity was likely dominated by EAWM from 18.5 ka to 7.5 ka and by the Westerlies after 7.5 ka across this area. We propose that increased NH ice volume (NHIV) significantly enhanced the EAWM via strengthening Siberian High, driving dust activities over the high mountains during the Last Deglaciation and Early Holocene. In contrast, as NHIV decreased during the middle-to-late Holocene, the EAWM weakened and retreated from this area, allowing the Westerlies to dominate dust activities. Additionally, grain-size parameters of sediments were used to infer variations in the intensities of these winds, revealing a gradual weakening of EAWM since the Last Deglaciation and a marked intensification of the Westerlies during the warm middle Holocene. Under the current global warming scenario, we predict that the Westerlies will continue to dominate dust activities across the NE-QTP, with a potential increase in dust activities if the Westerlies enhance.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"245 ","pages":"Article 104684"},"PeriodicalIF":4.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142884634","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":"U-series isotope constraints on the rates of aeolian-impacted basaltic weathering under tropical climate","authors":"Guodong Ming ,&nbsp;Jingyi Huang ,&nbsp;Jiaru Sheng ,&nbsp;Yingzeng Gong ,&nbsp;Jiye Guo ,&nbsp;Huimin Yu ,&nbsp;Wenhan Cheng ,&nbsp;Craig C. Lundstrom ,&nbsp;Fang Huang","doi":"10.1016/j.gloplacha.2024.104673","DOIUrl":"10.1016/j.gloplacha.2024.104673","url":null,"abstract":"<div><div>The chemical weathering of basalt rocks is crucial for stabilizing Earth's habitability and carbon cycle. Currently, the soil chemistry and weathering rates of basalt under significant aeolian influence are not fully understood. This study addresses this gap by investigating the U geochemistry and regolith production rates in a highly weathered basalt profile in Southern China. The ε_Nd(0) values decrease from the bedrock sample (4.68) to the top soils (0.94), indicating aerosol input from the top. Dust accretion decrease downward and significantly affects the vertical distribution of U (R² = 0.86), while the chemical mobilization of U is controlled by binding with Fe oxides-organic matter complexes (R² = 0.33).</div><div>The influence of dust accretion diminishes to insignificant (less than 9 % for U amount) below 330 cm, meeting the model's criteria for estimating U-series isotope-based regolith production rates. The estimated regolith production rates for depths of 445 cm, 370 cm, and 330 cm are ∼ 10 m/Myr, ∼ 5.5 m/Myr, and ∼ 3 m/Myr, respectively. These rates decrease with increasing depth, illustrating the depletion of soluble materials as the weathering profile thickens. CO₂ consumption fluxes calculated from soil chemistry (&lt; 193 × 10³ mol/km²/yr) are lower than those from river chemistry. Regolith development in the Leizhou Peninsula may account for &lt; 25 % of total chemical erosion, suggesting significant hidden erosion processes. These observations indicate that other potential weathering sources in aquifers and steeper terrains should be independently estimated when assessing basin-scale CO₂ consumption.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"245 ","pages":"Article 104673"},"PeriodicalIF":4.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142884685","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":"Temporal and spatial changes of glacial lakes in the central Himalayas and their response to climate change based on multi-source remote sensing data","authors":"Xiaoqiang Cheng ,&nbsp;Donghui Shangguan ,&nbsp;Chengsheng Yang ,&nbsp;Wangping Li ,&nbsp;Zhaoye Zhou ,&nbsp;Xiaojie Liu ,&nbsp;Da Li ,&nbsp;Xiuxia Zhang ,&nbsp;Huilan Ding ,&nbsp;Zewei Liu ,&nbsp;Yi Yu ,&nbsp;Xiaoxian Wang ,&nbsp;Beibei He ,&nbsp;Qin Yang ,&nbsp;Yaojun Li ,&nbsp;Rongjun Wang ,&nbsp;Yadong Liu ,&nbsp;Lingzhi Deng ,&nbsp;Yanzi Shi","doi":"10.1016/j.gloplacha.2024.104675","DOIUrl":"10.1016/j.gloplacha.2024.104675","url":null,"abstract":"<div><div>Global warming has significantly accelerated the retreat of glaciers and expansion of glacial lakes in the central Himalayas, thereby heightening the risks of various disasters, including ice avalanches, rock avalanches, and glacial lake outburst floods (GLOFs). These events pose considerable threats to the lives and properties of individuals residing in downstream areas. Consequently, conducting comprehensive research into the geographical distribution, formation, and evolutionary processes of glacial lakes, along with assessments of the potential impacts of GLOFs on climate change, is critically important for developing strategies to mitigate associated risks. To address this need, we propose a dynamic threshold method (known as OTSU) to facilitate the automatic and precise extraction of glacial lake boundaries in the central Himalayas. This innovative approach leverages the enhanced normalized difference water index (ENDWI), derived from multi-temporal Landsat series remote sensing imagery and Sentinel-2A /2B datasets, which were sourced from the Google Earth Engine (GEE) platform for the years 1990–2022. In addition to extracting lake boundaries, we examined the spatiotemporal evolution characteristics of glacial lakes in the region. Moreover, mathematical statistics were employed to systematically organize and analyse the GLOF disaster events in the central Himalayas. Finally, thoroughly investigate the interplay between glacial lake evolution and climate change, we incorporated relevant meteorological data. The present findings reveal that: 1) Glacial lakes are primarily distributed in the border area between China and Nepal in the central Himalayas, composed of non-contact lakes with glaciers, and concentrated in the altitude range of 3600–5900 m. 2) Since the 1990s, the expansion of glacial lakes is predominated by small glacial lakes in the central Himalayas; there have been 847 new glacial lakes, and the area and volume of glacial lakes has increased by 88.61 ± 4.64 km² and 24.72 ± 2.59 km³, respectively. 3) Global warming, coupled with the escalating rates of glacial meltwater, serves as the primary catalyst for the proliferation of glacial lakes. This multifaceted approach aims to provide a clearer understanding of the dynamics at play in this vulnerable region and to inform effective risk management strategies. Since 1950, there has been a significant increase in the frequency of GLOFs, with the month of June demonstrating the highest incidence, followed closely by August. These glacial lake outbursts are predominantly instigated by ice avalanches. The present findings provide valuable scientific insights that could contribute to the mitigation of regional natural disasters.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"245 ","pages":"Article 104675"},"PeriodicalIF":4.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841208","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":"Triggering of a 2500-year coral shutdown in northern South China Sea by coupled East Asian Monsoon and El Niño–Southern Oscillation","authors":"Fei Tan ,&nbsp;Yunfeng Zhang ,&nbsp;Guowei Fu ,&nbsp;Qi Shi ,&nbsp;Xiyang Zhang ,&nbsp;Shengnan Zhou ,&nbsp;Mingzhuang Wang ,&nbsp;Guotao Zhang ,&nbsp;Xiaoju Liu ,&nbsp;Jian-xin Zhao ,&nbsp;Hongqiang Yang","doi":"10.1016/j.gloplacha.2024.104672","DOIUrl":"10.1016/j.gloplacha.2024.104672","url":null,"abstract":"<div><div>Rapid climate change is reshaping the ecological dynamics of coral reefs, posing significant challenges in understanding the long-term effects of environmental disturbances on reef development. In the current study, we conducted a chronological analysis and regional review of Holocene massive <em>Porites</em> corals in the northern South China Sea, revealing a unique episodic growth pattern, including a 2500-year growth hiatus. The findings suggest that this collapse was driven by the coupling of intensified East Asian winter monsoon and broader-scale El Niño–Southern Oscillation variability. Regional environmental drivers significantly influenced spatiotemporal variations in coral growth stagnation across the Pan-Pacific region. While future sea level rise and warming may benefit nearshore corals, the projected intensification of El Niño–Southern Oscillation variability could undermine the potential of the northern South China Sea as a coral refuge. Effective coral management and environmental mitigation measures are crucial to preventing further collapse of regional coral reefs.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"245 ","pages":"Article 104672"},"PeriodicalIF":4.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841261","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":"Microbe-forced Mn‑carbonate direct precipitation in Ediacaran micro-stromatolites of South China","authors":"Yi Zhang ,&nbsp;Zhiwei Liao ,&nbsp;Qin Huang ,&nbsp;Gary G. Lash ,&nbsp;Jian Cao ,&nbsp;Bin Zhang","doi":"10.1016/j.gloplacha.2024.104658","DOIUrl":"10.1016/j.gloplacha.2024.104658","url":null,"abstract":"<div><div>The direct precipitation model of Mn‑carbonate formation, based on investigation of the modern sedimentary record and simulation experiments, is commonly used to explain the genesis of both modern and ancient Mn‑carbonate deposits. This process is considered to be primarily influenced by physicochemical conditions and lacks microbial mediation. Despite the established role of microbes in global Mn cycling and biomineralization, the specific contribution of microbial processes to Mn‑carbonate formation remains understudied. In this study, Ediacaran Mn‑carbonates from South China with well-preserved micro-stromatolites offer a novel insight into understanding the microbes involved in the formation of Mn-deposits. Petrological observations reveal that the laminated Mn-ores mainly consist of alternating layers of dark Mn‑carbonate and light-colored dolomite laminae. Mn‑carbonate minerals, dominantly rod-like rhodochrosite crystals, exhibit a close spatial relationship with micro-stromatolites, suggesting a possible link to microbial activity. Geochemical results display that these Mn‑carbonates document high δ¹³C values (average = −1.65 ‰) compared to typical diagenetic Mn‑carbonate indicating the seawater likely contributed to the carbon source. Combined with alabandite deposition, small-sized pyrite framboids, and positive Eu anomalies, the Ediacaran Mn‑carbonates may have formed by microbially-mediated direct precipitation in Mn-rich anoxic seawater. The Mn‑carbonate and micro-stromatolite laminae accumulated during a period of enhanced bacterial activity, driven by episodic inputs of hydrothermal Mn²⁺ and bioessential elements. The present study highlights the microbially-mediated significant role in the primary precipitation pathway of Mn‑carbonate. Direct precipitation of Mn‑carbonate deposits, controlled by ocean conditions as well as enhanced by microbial processes, may account for the formation of other ancient economic manganiferous sedimentary deposits.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"245 ","pages":"Article 104658"},"PeriodicalIF":4.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142760834","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":"First report of the Pingding locality of the Balang Lagerstätte (Cambrian Stage 4), South China: Implications for community complexity and geographic variation","authors":"Dezhi Wang ,&nbsp;Shengguang Chen ,&nbsp;Wenyu Ma ,&nbsp;Xiuchun Luo ,&nbsp;Yifan Wang ,&nbsp;Fangchen Zhao ,&nbsp;Xinglian Yang","doi":"10.1016/j.gloplacha.2024.104641","DOIUrl":"10.1016/j.gloplacha.2024.104641","url":null,"abstract":"<div><div>Exceptionally preserved fossil deposits provide detailed information on fossil assemblages and critical data that illustrate the complexities of Cambrian marine ecosystems. The Balang Lagerstätte (Cambrian Stage 4), one of the important biotas from the slope facies of Guizhou Province, yields diverse and abundant well–preserved fossils distributed across a variety of fossil localities. Here we present the first report of a new soft–bodied fossil assemblage from the Balang Formation in Pingding Village, Majiang County, outside the area from which soft–bodied fossils were previously known to occur. This new fossil site contains a variety of exquisite fossils including sponges, chancelloriids, cnidarians, hyoliths, brachiopods, arthropods, priapulids and vetulicolians. Compared with other Balang localities, the Pingding fossil assemblage is a brachiopod-dominated palaeocommunity with diverse arthropods. Results of a detailed comparative study indicate that the Balang localities are highly heterogeneous in fossil composition. In addition, the discovery of this new locality bridges the environmental gap between the offshore and slope palaeoenvironments, and offers a unique opportunity to investigate the factors responsible for differences in palaeocommunity composition. In general, these findings illustrate great community complexity in the Balang Lagerstätte which reflects ecospace utilization along an environmental gradient in the aftermath of the Cambrian Explosion.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"245 ","pages":"Article 104641"},"PeriodicalIF":4.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142760835","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}