Global and Planetary Change最新文献

{"title":"Sedimentary responses to climatic variations and Kuroshio intrusion into the northern South China Sea since the last deglaciation","authors":"Chao Huang, Liyuan Wu, Jiansen Cheng, Xiaoxu Qu, Yongyi Luo, Huiling Zhang, Feng Ye, Gangjian Wei","doi":"10.1016/j.gloplacha.2024.104671","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104671","url":null,"abstract":"The terrigenous sediment source-to-sink processes in marginal seas are governed by intricate interactions among climate, sea level, and ocean currents. The continental slope of the northern South China Sea (SCS) provides an excellent setting to examine these processes due to its substantial terrigenous influx and continuous sedimentation. In this study, we present a high-resolution sedimentary record from the northern SCS continental slope covering the last deglaciation. Analyses of Rare Earth Elements (REEs) and Sr–Nd isotopic compositions in the NH07 core indicate that the predominant source of terrigenous sediment was Taiwan. Grain size-standard deviation analysis identified two sensitive grain size components, with the sensitive component 2 used as a marker of the Kuroshio intrusion into the northern SCS through Luzon Strait. The intensity of the Kuroshio intrusion into the northern SCS was found to be inversely related to that of the open Pacific. The Asian monsoon and El Niño-Southern Oscillation (ENSO) significantly influenced the variability of the Kuroshio Current throughout the deglaciation period. During the interval 16, 000–11, 700 cal yr BP, variations in terrigenous influx were collectively driven by sea level changes and the intensity of the Kuroshio intrusion, while chemical weathering intensity was affected by the reworking of previously exposed shelf sediments due to sea level fluctuations. During the Holocene, however, the East Asian summer monsoon intensity became the primary factor influencing variations in terrigenous influx and chemical weathering.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"78 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841259","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":"Magnetic susceptibility cyclostratigraphy of the lower Schwarzrand Subgroup in southern Namibia refines temporal calibration of late Ediacaran bilaterian radiation","authors":"Zheng Gong, Iona Baillie, Lyle L. Nelson, Stacey H. Gerasimov, Catherine Rose, Emily F. Smith","doi":"10.1016/j.gloplacha.2024.104668","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104668","url":null,"abstract":"The Nama Group in southern Namibia captures one of the best-preserved records of the last ∼10 million years of the Ediacaran Period, recording pivotal changes to Earth's biosphere and oceans. Within the Nama Group, the lower Schwarzrand Subgroup preserves early complex bilaterian trace fossils, but uncertainties surrounding the ages of their first occurrences hinder global correlation and the understanding of the rates at which critical biological changes occurred. This study presents magnetic susceptibility cyclostratigraphy of a recently acquired drill core that covers the Nudaus Formation and Nasep Member within the lower Schwarzrand Subgroup. Spectral analysis reveals a hierarchy of orbital cycles that could be responsible for the repeating depositional sequences at various length scales in the Schwarzrand Subgroup. Matching the wavelengths of the orbital cycles to their expected periodicities, we established sedimentation rates throughout the stratigraphy. Utilizing available U<ce:glyph name=\"sbnd\"></ce:glyph>Pb ages from correlative outcrop sections and the sedimentation rates from cyclostratigraphy, we refine the age-depth model for the lower Schwarzrand Subgroup. Our new age-depth model places tighter temporal constraints on the first appearances of complex trace fossils, thus constraining the earliest major radiation of bilaterian metazoans and contributing to a better-calibrated chronostratigraphy of the terminal Ediacaran Period.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"7 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797879","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":"Influence of climatic variables on biome transitions in the Colombian and Panamanian Caribbean region","authors":"Y. Nuñez-Bolaño, N. Hoyos, A. Correa-Metrio, C. Martínez, C. Pizano, J. Escobar, C. Huertas, C. Jaramillo","doi":"10.1016/j.gloplacha.2024.104669","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104669","url":null,"abstract":"Disentangling the environmental determinants of tropical biomes is crucial for understanding their response to climate change. This study investigated the effect of climate and soil-related variables on biome transitions in the Caribbean region of Colombia and Panama, focusing on xerophytic forest (XF), tropical dry forest (TDF), and tropical rainforest (TRF). We analyzed the climatic variables at different time scales (daily, seasonal, and annual) and their interaction with soil properties. We performed an ordinal logistic regression to assess the combined effect of the most important variables in biome transitions. Our results showed that climate variables are major discriminators in our study region, particularly precipitation at a seasonal and annual scale. The ordinal logistic regression highlighted the significance of annual precipitation and dry-season length in biome transitions, with maximum temperature impacting TDF-TRF transitions. Soil differences, although present (e.g., higher sand content in XF), played a marginal role. Overall, our findings emphasize the dominance of climate over soil in shaping tropical biome distributions in the northern Caribbean part of South America. These findings contribute to a deeper understanding of tropical biome responses to climate change.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"41 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797880","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":"Large ensemble simulations indicate increases in spatial compounding of droughts and hot extremes across multiple croplands in China","authors":"Boying Lv, Zengchao Hao, Yutong Jiang, Qian Ma, Yitong Zhang","doi":"10.1016/j.gloplacha.2024.104670","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104670","url":null,"abstract":"The simultaneous occurrence of extremes (e.g., droughts) at multiple regions (usually termed as spatial compounding of extremes), such as croplands, may lead to large impacts on global food security. Recently, the concurrent droughts and hot extremes at a specific location, which are referred to as compound droughts and hot extremes (CDHEs), have garnered considerable attention due to the potentially amplified impacts of individual extremes. Though the spatial compounding of individual droughts or hot extremes has been assessed, the variability of the spatial compounding of CDHEs across multiple croplands in China has been lacking due to relatively short records or small sample sizes. In this study, we evaluated changes in the spatial compounding of CDHEs across multiple croplands in China, including Songnen Plain (SN), North China Plain (NC), and Sichuan Basin (SC), based on precipitation and temperature data from CN05.1 and large ensemble model (CESM1-CAM5). Results show that the frequency of CDHEs in each region will increase in future periods especially for the eastern SN, central NC, and northern SC (increase by more than 15 months), with more than 70 % of the 40 ensemble members showing a large increase. Projected changes of different cases of spatial compounding of CDHEs in three croplands (i.e., SN-NC, NC-SC, SN-SC, SN-NC-SC) showed increases from 1961–2010 to 2031–2080. In particular, higher increases in the spatial compounding of CDHEs in the NC-SC region are projected (from 0.58 to 3.73 months on average), with the ratio of non-zero event members increasing from 47.5 % to 95 %. These results underscore the high risk of the spatial compounding of extremes at multiple croplands in China in the future.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"256 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841260","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 dust activity in inland Asia driven by both the mid-latitude Westerlies and the East Asian winter monsoon","authors":"Haipeng Wang, Jianhui Chen, Yuanhao Sun, Ruijin Chen, Nasetay Aydenbek, Jianbao Liu","doi":"10.1016/j.gloplacha.2024.104661","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104661","url":null,"abstract":"Inland Asia is a major global source of dust and the dust transport from this region has global implications. However, the processes and forcing mechanisms of dust activity in inland Asia during the Holocene are still debated due to the lack of high-quality records with accurate dating, unambiguous dust signals, and a high resolution. Here we present a well-dated record of dust activity based on the Ti content of the sediments of Shuanghu Lake, in the southern Altai Mountains, with a ∼ 15-yr-resolution and covering the entire Holocene. This record shows a gradual decrease in dust intensity during ∼11.7–6 thousand years ago (ka), followed by a persistent increase since ∼6 ka. Frequent dust events are also evident, lasting hundreds of years, and are superimposed on the millennial-scale trend, corresponding to the nine North Atlantic Bond events. We propose that the millennial-scale trend of dust activity was primarily influenced by variations in the mid-latitude Westerlies, while the dust events on the centennial scale were driven primarily by a strengthened East Asian winter monsoon. Overall, this study provides a reliable, high-resolution record of Holocene dust activity in inland Asia, and it updates the previous view that dust activity in this region was solely controlled by the mid-latitude Westerlies or the Siberian High. Our findings contribute to an improved understanding of global dust transport with implications for predicting future dust activity in this region.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"12 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797881","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":"Dual carbon isotopes constrain the sources and age variations of terrestrial organic carbon in the middle Okinawa Trough since the last deglaciation","authors":"Mengna Chen, Chenglong Su, Shuang Wang, Da-Wei Li, Hailong Zhang, Li Li, Guangxue Li, Bingyuan Xu, Jishang Xu, Meixun Zhao","doi":"10.1016/j.gloplacha.2024.104660","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104660","url":null,"abstract":"The burial of terrestrial organic carbon (OC) in marine sediments is a crucial process in the global carbon cycle, as it transfers carbon from relatively active to inactive reservoirs. However, there remains a limited understanding of the spatial and temporal variations in the source and age characteristics of terrestrial OC in marine sediments, which determine its ability to serve as a contemporary carbon sink. In this study, radiocarbon isotope (<ce:sup loc=\"post\">14</ce:sup>C, expressed as F<ce:sup loc=\"post\">14</ce:sup>C) analysis was conducted on bulk OC from a sediment core (M063–05) collected from the middle Okinawa Trough, with core depositional ages spanning 1.5–16.1 ka. A novel mathematical approach was developed to differentiate the carbon isotope signals of terrestrial OC from those of bulk OC properties, enabling the investigation of the source, age, and burial flux of terrestrial OC in the Okinawa Trough. Our results indicate that sedimentary OC in the Okinawa Trough was predominantly composed of marine OC (average proportion, 58 %), with terrestrial OC present to a lesser extent (average proportion, 42 %). Terrestrial OC in core M063–05 was found to be primarily a mixture of terrestrial OC from the Huanghe (Yellow River) and petrogenic OC from Taiwan Island, and the apparent initial ages of terrestrial OC (AIR<ce:inf loc=\"post\">terrestrial</ce:inf>) exhibited higher values of 7933–8886 yr during the mid-late Holocene compared to 3062–7677 yr during the marine transgression stage. The elevated AIR<ce:inf loc=\"post\">terrestrial</ce:inf> during sea level highstand was attributed to (1) increased petrogenic OC input from Taiwan Island due to the intensified Kuroshio Current, which transports material from Taiwan northward along the Okinawa Trough, and (2) vigorous hydrodynamic processes in the continental shelves of the East China marginal seas, leading to significant aging of terrestrial OC during lateral transport. This innovative dual carbon isotope-based approach (enumeration method) elucidates the temporal variations in terrestrial OC sources and age characteristics in a typical continental slope within the western Pacific Ocean, providing a framework for investigating the sources and fate of terrestrial OC in marginal seas, especially in scenarios where potential changes in carbon isotope endmembers occur in response to climate and environmental changes.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"238 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797882","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":"Basin-scale spatio-temporal development of glacial lakes in the Hindukush-Karakoram-Himalayas","authors":"Atul Kumar ,&nbsp;Suraj Mal ,&nbsp;Udo Schickhoff ,&nbsp;A.P. Dimri","doi":"10.1016/j.gloplacha.2024.104656","DOIUrl":"10.1016/j.gloplacha.2024.104656","url":null,"abstract":"<div><div>Glacial lakes are expanding exponentially in the cryospheric environment of the Hindukush-Karakoram-Himalayas (HKH). Rapid glacier melting due to an above mean global annual temperature increase in HKH is attributed as the main reason for the expansion of the glacial lakes. The rapid expansion of glacial lakes increases the risk of future Glacial Lake Outburst Floods (GLOFs) events in the HKH.</div><div>In the present study, glacial lake inventories for the Indus, Ganga and Brahmaputra (IGB) river basins in the HKH were generated for 1990, 2000, 2010 and 2020 using Landsat (TM &amp; OLI) at the sub-basin level to understand the spatio-temporal and regional patterns of glacial lakes dynamics, elevational evolution, and changes in the typology. We mapped 17,641 glacial lakes (area: 1082.57 ± 192.601 km²) in 1990, 18,206 (area: 1120.95 ± 198.49 km²) in 2000, 18,399 (area: 1147.12 ± 201.26 km²) in 2010, and 19,284 (area: 1191.81 ± 209.21 km²) in 2020. Between 1990 and 2020, IGB basins showed an increase of 9.31 % in total number and 10.09 % in total area of glacial lakes. In 2020, the Brahmaputra basin had the maximum total area (area: 763.59 ± 132.14 km²), followed by Indus basin (area: 217.47 ± 43.39 km²) and the Ganga basin (area: 210.74 ± 33.66 km²). However, between 1990 and 2020, glacial lakes in the Ganga basin (n: 22.08 %) had the highest growth rate, followed by the Indus basin (n: 14.73 %) and the Brahmaputra basin (n: 4.41 %). In 2020, 76.11 % of glacial lakes were end-moraine-dammed M(e) lakes, followed by other bedrock-dammed B(o) lakes (16.45 %), supraglacial lakes (2.79 %), lateral moraine-dammed M(l) lakes (2 %), cirque B(c) lakes (1.06 %), other moraine-dammed M(o) lakes (0.38 %), and other glacial (O) lakes (1.18 %). Given the rapid growth of glacial lakes in the region along with their likely flood volumes and damage potential in case of their failures, the present study will be of importance for disaster management authorities, an important input for detection of potentially hazardous glacial lakes and for development of mitigation strategies to minimize the impact of potential future GLOF events.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"245 ","pages":"Article 104656"},"PeriodicalIF":4.0,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746654","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":"Zooplankton fecal pellet flux and carbon export: The South China Sea record and its global comparison","authors":"Jiaying Li,&nbsp;Zhifei Liu,&nbsp;Baozhi Lin,&nbsp;Yulong Zhao,&nbsp;Xiaodong Zhang,&nbsp;Junyuan Cao,&nbsp;Jingwen Zhang,&nbsp;Hongzhe Song","doi":"10.1016/j.gloplacha.2024.104657","DOIUrl":"10.1016/j.gloplacha.2024.104657","url":null,"abstract":"<div><div>Zooplankton fecal pellets constitute a major component of passively sinking particles in the ocean. The sinking of zooplankton fecal pellets provides an efficient vehicle for the transfer and sequestration of particulate organic carbon (POC) in the deep sea, which has been widely reported in different regions. However, most existing studies focus on the sinking flux of fecal pellets within the upper ocean, while lower mesopelagic and bathypelagic zones are rarely investigated. Here, we report the spatiotemporal flux variation of zooplankton fecal pellets collected by two sediment traps deployed in mesopelagic and bathypelagic zones (500 m and 2190 m, respectively) of the South China Sea from June 2020 to May 2022, and compare it with deep-sea (&gt;500 m) fecal pellet flux data reported in the global ocean. In the South China Sea, fecal pellet fluxes display distinct seasonal patterns due to the control of the East Asian monsoon system, with higher fluxes in winter and spring, and lower fluxes in summer and autumn. Small fecal pellets (width &lt; 100 μm) dominate the overall pellet numerical flux (more than 98 %), while rare large pellets (width &gt; 100 μm) account for averaging 20 % of fecal pellet carbon flux. Both large and small pellet fluxes appear to be higher at 2190 m, mainly due to the in-situ reworking and repackaging of deep-dwelling zooplankton communities, as well as the input of lateral advection from high productive continental coasts and shelves. Identifiable zooplankton fecal pellets constitute approximately 10 % to the total POC flux in the deep South China Sea. Comparing the eutrophic polar and upwelling regions with mesotrophic and oligotrophic regions, we find a good correlation between marine primary production and fecal pellet carbon export. On the global scale, carbon fluxes through zooplankton fecal pellets to the deep sea are mainly constrained by the grazing impacts of zooplanktons, influenced by temperature, zooplankton biomass, and zooplankton size spectrum.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"245 ","pages":"Article 104657"},"PeriodicalIF":4.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746655","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, Zhiwei Liao, Qin Huang, Gary G. Lash, Jian Cao, Bin Zhang","doi":"10.1016/j.gloplacha.2024.104658","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104658","url":null,"abstract":"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 δ<ce:sup loc=\"post\">13</ce:sup>C 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 Mn<ce:sup loc=\"post\">2+</ce:sup> 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.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"7 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-11-26","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":"Nanoparticles of iridium and other platinum group elements identified in Chicxulub asteroid impact spherules – Implications for impact winter and profound climate change","authors":"Vivi Vajda, Susan Nehzati, Gavin Kenny, Hermann D. Bermúdez, Ashley Krüger, Alexander Björling, Adriana Ocampo, Ying Cui, Kajsa G.V. Sigfridsson Clauss","doi":"10.1016/j.gloplacha.2024.104659","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104659","url":null,"abstract":"The Chicxulub asteroid that ended the Cretaceous Era ∼66.05 million years ago caused a prolonged time of global darkness – the impact winter – leading to mass extinctions. Elements from the asteroid, including the platinum group elements (PGEs) osmium, iridium and platinum are known from the globally distributed boundary clay but their carrier elements have so far been unknown. We identify, for the first time in detail, the presence of these PGEs within Chicxulub impact spherules and importantly, we identify their carrier elements. We show through synchrotron Nano-XRF how these PGEs occur in nanostructures as un-ordered cube- and/or needle-like crystals co-localizing with both siderophile and chalcophile elements including Co, Ni, Cu, Zn, and Pb, derived from the asteroid. These crystals are set within a matrix of iron-rich calcium and silica glass revealing the mix of vaporized target rock and the asteroid. The results provide insights into the combination of elements present in the spherules, indicating formation of new minerals. We argue that the nano-shards of unreactive elements such as platinum, iridium and copper acted as nuclei for aerosol formation and potentially contributed to a prolonged impact winter with darkness and cooling leading to a profound and long-term climate change.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"20 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797885","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}