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Soil moisture gradients strengthen mesoscale convective systems by increasing wind shear
IF 18.3 1区 地球科学
Nature Geoscience Pub Date : 2025-04-04 DOI: 10.1038/s41561-025-01666-8
Emma J. Barton, Cornelia Klein, Christopher M. Taylor, John Marsham, Douglas J. Parker, Ben Maybee, Zhe Feng, L. Ruby Leung
{"title":"Soil moisture gradients strengthen mesoscale convective systems by increasing wind shear","authors":"Emma J. Barton, Cornelia Klein, Christopher M. Taylor, John Marsham, Douglas J. Parker, Ben Maybee, Zhe Feng, L. Ruby Leung","doi":"10.1038/s41561-025-01666-8","DOIUrl":"https://doi.org/10.1038/s41561-025-01666-8","url":null,"abstract":"<p>Mesoscale convective systems are a class of storm linked to extensive flooding and other destructive hazards in many regions globally. In West Africa, soil moisture impacts provide a valuable source of predictability for mature storm hazards, but little is known about mature storm sensitivity to soil moisture in other climatic regions. Here we use a storm track dataset, satellite observations and reanalysis fields to investigate the response of mature storms to soil moisture in seven global storm hotspots—West Africa, India, South America, South Africa, Australia and the United States Great Plains. We demonstrate that mesoscale soil moisture gradients (~500 km) can enhance storms by driving increased vertical wind shear conditions, a crucial ingredient for storm organization, through the strengthening of atmospheric temperature gradients. This is evidenced by a 10–30% increase in precipitation feature size and rainfall for the largest storms on days with favourable soil moisture gradients compared with unfavourable gradients. Global simulations confirm that soil moisture gradients influence wind shear. The results demonstrate the importance of soil moisture feedbacks for accurate forecasting of mesoscale convective systems and future projections of extreme events under climate change.</p>","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"20 1","pages":""},"PeriodicalIF":18.3,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143775406","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}
引用次数: 0
Elevated δ15N Linked to Inhibited Nitrification Coupled to Ammonia Volatilization in Sediments of Shallow Alkaline-Hypersaline Lakes
IF 2.7 2区 地球科学
Geobiology Pub Date : 2025-04-04 DOI: 10.1111/gbi.70018
Christopher J. Tino, Eva E. Stüeken, Daniel D. Gregory, Timothy W. Lyons
{"title":"Elevated δ15N Linked to Inhibited Nitrification Coupled to Ammonia Volatilization in Sediments of Shallow Alkaline-Hypersaline Lakes","authors":"Christopher J. Tino,&nbsp;Eva E. Stüeken,&nbsp;Daniel D. Gregory,&nbsp;Timothy W. Lyons","doi":"10.1111/gbi.70018","DOIUrl":"https://doi.org/10.1111/gbi.70018","url":null,"abstract":"<p>Alkaline lakes are among the most bioproductive aquatic ecosystems on Earth. The factors that ultimately limit productivity in these systems can vary, but nitrogen (N) cycling in particular has been shown to be adversely affected by high salinity, evidently due to the inhibition of nitrifying bacteria (i.e., those that convert ammonic species to nitrogen oxides). The coastal plain of Coorong National Park in South Australia, which hosts several alkaline lakes along 130 km of coastline, provides an ideal natural laboratory for examining how fine-scale differences in the geochemistry of such environments can lead to broad variations in nitrogen cycling through time, as manifest in sedimentary δ<sup>15</sup>N. Moreover, the lakes provide a gradient of aqueous conditions that allows us to assess the effects of pH, salinity, and carbonate chemistry on the sedimentary record. We report a wide range of δ<sup>15</sup>N values (3.8‰–18.6‰) measured in the sediments (0–35 cm depth) of five lakes of the Coorong region. Additional data include major element abundances, carbonate δ<sup>13</sup>C and δ<sup>18</sup>O values, and the results of principal component analyses. Stable nitrogen isotopes and wt% sodium (Na) display positive correlation (<i>R</i><sup>2</sup> = 0.59, <i>p</i> &lt; 0.001) across all lake systems. Principal component analyses further support the notion that salinity has historically impacted nitrogen cycling. We propose that the inhibition of nitrification at elevated salinity may lead to the accumulation of ammonic species, which, when exposed to the water column, are prone to ammonia volatilization facilitated by intervals of elevated pH. This process is accompanied by a significant isotope fractionation effect, isotopically enriching the nitrogen that remains in the lake water. This nitrogen is eventually buried in the sediments, preserving a record of these combined processes. Analogous enrichments in the rock record may provide important constraints on past chemical conditions and their associated microbial ecologies. Specifically, ancient terrestrial aquatic systems with high δ<sup>15</sup>N values attributed to denitrification and thus oxygen deficiency may warrant re-evaluation within the framework of this alternative. Constraints on pH as provided by elevated δ<sup>15</sup>N via ammonia volatilization may also inform critical aspects of closed-basin paleoenvironments and their suitability for a de novo origin of life.</p>","PeriodicalId":173,"journal":{"name":"Geobiology","volume":"23 2","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gbi.70018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The Role of Long-Term Hydrodynamic Evolution in the Accumulation and Preservation of Organic Carbon-Rich Shelf Sea Deposits
IF 3.3 2区 地球科学
Journal of Geophysical Research-Oceans Pub Date : 2025-04-04 DOI: 10.1029/2024JC022092
S. L. Ward, S. L. Bradley, Z. A. Roseby, S.-B. Wilmes, D. F. Vosper, C. M. Roberts, J. D. Scourse
{"title":"The Role of Long-Term Hydrodynamic Evolution in the Accumulation and Preservation of Organic Carbon-Rich Shelf Sea Deposits","authors":"S. L. Ward,&nbsp;S. L. Bradley,&nbsp;Z. A. Roseby,&nbsp;S.-B. Wilmes,&nbsp;D. F. Vosper,&nbsp;C. M. Roberts,&nbsp;J. D. Scourse","doi":"10.1029/2024JC022092","DOIUrl":"https://doi.org/10.1029/2024JC022092","url":null,"abstract":"<p>Understanding and mapping seabed sediment distribution in shelf seas is essential for effective coastal management, offshore developments, and for blue carbon stock assessments and conservation. Fine-grained marine sediments, particularly muds, play a key role in long-term organic carbon sequestration, so knowledge of the spatial extent of these carbon-rich deposits is important. Here, we consider how changes in shelf sea tidal dynamics since the Last Glacial Maximum have influenced the development of three mud depocenters in the northwest European shelf seas: the Fladen Ground, the Celtic Deep, and the Western Irish Sea Mud Belt. Using a new high-resolution paleotidal model, we demonstrate how the evolution of simulated tidal parameters, including bed shear stress and bottom boundary layer thickness, differ across these sites. Geological data support our findings, indicating that long-term mud sedimentation continues to the present in the Celtic Deep and Western Irish Sea Mud Belt, while in the Fladen Ground, accumulation cannot be fully explained by contemporary hydrodynamics. In the latter, mud deposition is relict, deposited during quiescent tidal conditions between 17,000 and 5,000 years ago. We suggest that simulating paleoceanographic conditions can contribute to understanding first-order sediment dynamics over large spatial and temporal scales, a key input for predictive mapping and regional blue carbon inventories. This approach is a valuable first step in data-poor regions to identify potential fine sediment deposits. By illustrating the temporal evolution of organic carbon-rich deposits, we provide a broader context for managing organic carbon storage in shelf sea sedimentary environments.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC022092","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Written in ‘her’ bones: Cremation and identity in Roman Beirut
IF 2.6 1区 地球科学
Journal of Archaeological Science Pub Date : 2025-04-04 DOI: 10.1016/j.jas.2025.106153
Vana Kalenderian , Tim J.U. Thompson , Deandra De Looff , Alexander P.H. Surtees , Geoff M. Nowell , Georges El Haibe , Assaad Seif
{"title":"Written in ‘her’ bones: Cremation and identity in Roman Beirut","authors":"Vana Kalenderian ,&nbsp;Tim J.U. Thompson ,&nbsp;Deandra De Looff ,&nbsp;Alexander P.H. Surtees ,&nbsp;Geoff M. Nowell ,&nbsp;Georges El Haibe ,&nbsp;Assaad Seif","doi":"10.1016/j.jas.2025.106153","DOIUrl":"10.1016/j.jas.2025.106153","url":null,"abstract":"<div><div>At the time of its annexation in the 1st c. BC, cremation was not a customary practice in the Roman province of Syria. This contrasts with the western provinces of the Empire, where burning the body for burial remained the method of choice until the turn of the 2nd c. AD. As such, the discovery of cremation burials in the Roman Near East raises questions about the identities and origins of the buried individuals. This article focuses on one such example from Berytus, the first Roman colony in the Near East (modern Beirut, Lebanon). It implements a multidisciplinary approach through osteological, chemical, and material analyses to explore various aspects of mortuary practice and identity. Osteological and isotopic results indicate that the buried individual was likely a female of non-local origin. On the other hand, FTIR-ATR analysis, along with the macroscopic examination of the bones, suggest the burning of a fresh body at elevated temperatures. Furthermore, exceptional environmental conditions led to the formation of calcite crystals within the urn and on the human remains, which were identified using Raman spectroscopy. Similarly, unique burial conditions resulted in the preservation of textile pseudomorphs, which offer rare insights into body treatment practices that are typically absent from the archaeological record of the Levantine coast. By contextualizing the different bioarchaeological and material findings, this study reconstructs the life-history of the interred individual and examines the social and cultural significance of this burial within the context of the Roman colonization of Beirut.</div></div>","PeriodicalId":50254,"journal":{"name":"Journal of Archaeological Science","volume":"177 ","pages":"Article 106153"},"PeriodicalIF":2.6,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143768844","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}
引用次数: 0
Anomalous Shear Stress Variation in Wet Granular Medium: Implications for Landslide Lateral Faults
IF 4.6 1区 地球科学
Geophysical Research Letters Pub Date : 2025-04-04 DOI: 10.1029/2024GL113816
Chengrui Chang, Kohei Ohno, William H. Schulz, Tetsuo Yamaguchi
{"title":"Anomalous Shear Stress Variation in Wet Granular Medium: Implications for Landslide Lateral Faults","authors":"Chengrui Chang,&nbsp;Kohei Ohno,&nbsp;William H. Schulz,&nbsp;Tetsuo Yamaguchi","doi":"10.1029/2024GL113816","DOIUrl":"https://doi.org/10.1029/2024GL113816","url":null,"abstract":"<p>Landslide assessments typically focus on the mechanical properties of the basal shear zone, but lateral faults are frequently overlooked, possibly due to their lower normal stresses and variably saturated conditions. Using double-cylinder shear experiments on wet granular systems as analogs for landslide lateral faults, we observe anomalous shear stress variations with fluid volume fractions, defying an expected unimodal relationship associated with capillary cohesion. At low fluid volume fractions, shear strength weakens as the wet grain assembly experiences reduced lateral pressure and increased boundary slip. This boundary slip subsequently vanishes, with an abrupt strengthening due to the dilation of the grain assembly against fluid surface tension as saturation approaches. Strike-slip motion and confinement in this system explain the strength anomaly, highlighting a critical role of lateral faults in landslide stability, particularly in cases where dynamics cannot be adequately explained by monitored pore-water pressure or basal friction.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 7","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL113816","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770037","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}
引用次数: 0
Satellite Traces: Ionogram Signatures of Bottom-Side Upwelling Structures - A Simulation Study
IF 4.6 1区 地球科学
Geophysical Research Letters Pub Date : 2025-04-04 DOI: 10.1029/2024GL114119
M. Ankita, S. Tulasi Ram, T. Yokoyama, R. T. Tsunoda, A. P. Dimri, S. Mondal, Chinmaya Nayak
{"title":"Satellite Traces: Ionogram Signatures of Bottom-Side Upwelling Structures - A Simulation Study","authors":"M. Ankita,&nbsp;S. Tulasi Ram,&nbsp;T. Yokoyama,&nbsp;R. T. Tsunoda,&nbsp;A. P. Dimri,&nbsp;S. Mondal,&nbsp;Chinmaya Nayak","doi":"10.1029/2024GL114119","DOIUrl":"https://doi.org/10.1029/2024GL114119","url":null,"abstract":"<p>Satellite Traces (STs) are the important ionogram signatures for the presence of upwellings in the bottom-side ionosphere, which provide the necessary seed perturbation for the development of equatorial plasma bubbles (EPBs). In this study, a virtual ionosonde experiment is simulated to investigate the various ST signatures under the presence of shallow, deep, overhead, and off-centered upwellings in the bottom-side ionosphere. It is shown that STs occur at higher and lower virtual heights than the main ionogram trace for the off-centered and overhead upwellings, respectively. The height separation between the main trace and STs increases with the deepening of overhead upwellings. Further, a proof-of-concept is demonstrated that multiple STs from ionograms can be used to reconstruct the spatial structure of bottom-side upwellings, if the precise Angle-of-Arrival information can be resolved from the wide beam Ionosonde systems, and can have potential applications in predicting the occurrence of EPBs.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 7","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL114119","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770132","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}
引用次数: 0
Close Correlation Between Vertically Integrated Tropospheric Water Vapor and the Downward, Broadband Thermal-Infrared Irradiance at the Ground: Observations in the Central Arctic During MOSAiC
IF 3.8 2区 地球科学
Journal of Geophysical Research: Atmospheres Pub Date : 2025-04-04 DOI: 10.1029/2024JD042378
Clara Seidel, Dietrich Althausen, Albert Ansmann, Manfred Wendisch, Hannes Griesche, Martin Radenz, Julian Hofer, Sandro Dahlke, Marion Maturilli, Andreas Walbröl, Holger Baars, Ronny Engelmann
{"title":"Close Correlation Between Vertically Integrated Tropospheric Water Vapor and the Downward, Broadband Thermal-Infrared Irradiance at the Ground: Observations in the Central Arctic During MOSAiC","authors":"Clara Seidel,&nbsp;Dietrich Althausen,&nbsp;Albert Ansmann,&nbsp;Manfred Wendisch,&nbsp;Hannes Griesche,&nbsp;Martin Radenz,&nbsp;Julian Hofer,&nbsp;Sandro Dahlke,&nbsp;Marion Maturilli,&nbsp;Andreas Walbröl,&nbsp;Holger Baars,&nbsp;Ronny Engelmann","doi":"10.1029/2024JD042378","DOIUrl":"https://doi.org/10.1029/2024JD042378","url":null,"abstract":"&lt;p&gt;The impact of the vertical distribution of tropospheric water vapor on the cloud-free downward, broadband thermal-infrared irradiance &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;F&lt;/mi&gt;\u0000 &lt;mtext&gt;TIR&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $left({F}_{text{TIR}}right)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; was quantified using observations in the Central Arctic, north of 85°N, collected during the Arctic winter. The water vapor profiles were measured with a temporal resolution of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;30&lt;/mn&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $30,mathrm{s}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; using a Raman lidar. The observations revealed maximum values of integrated water vapor (IWV) contents of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;3.6&lt;/mn&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mi&gt;k&lt;/mi&gt;\u0000 &lt;mi&gt;g&lt;/mi&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;m&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $3.6,mathrm{k}mathrm{g} {mathrm{m}}^{-mathrm{2}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. Seven measurement cases of several-hour durations of slowly changing air masses were examined. Furthermore, 53 rather short-term (10 min) measurement cases were studied. The temporal evolution of the slowly changing air masses revealed a linear relationship between &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;F&lt;/mi&gt;\u0000 &lt;mtext&gt;TIR&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${F}_{text{TIR}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and IWV with slopes between 7.17 and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;12.95&lt;/mn&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mi&gt;W&lt;/mi&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mi&gt;k&lt;/mi&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;g&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $12.95,mathrm{W} mathrm{k}{mathrm{g}}^{-mathrm{1}}$&lt;/annotatio","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 7","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD042378","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Standard Thermodynamic Properties of Ag3Sn (Shosanbetsuite): EMF Data
IF 0.7 4区 地球科学
Geochemistry International Pub Date : 2025-04-04 DOI: 10.1134/S0016702924700861
M. V. Voronin, E. G. Osadchii
{"title":"Standard Thermodynamic Properties of Ag3Sn (Shosanbetsuite): EMF Data","authors":"M. V. Voronin,&nbsp;E. G. Osadchii","doi":"10.1134/S0016702924700861","DOIUrl":"10.1134/S0016702924700861","url":null,"abstract":"<p>Thermodynamic properties of shosanbetsuite (Ag<sub>3</sub>Sn) are first determined in the Ag–Sn system in a galvanic cell (–) Pt|Gr|Ag|RbAg<sub>4</sub>I<sub>5</sub>|Ag<sub>3</sub>Sn, Sn|Gr|Pt (+) within the temperature range of 327–427 K in vacuum. Analysis of the data makes it possible to calculate the standard (298.15 K, 10<sup>5</sup> Pa) Δ<sub><i>f</i></sub><i>G</i>°, Δ<sub><i>f</i></sub><i>H</i>°, and <i>S</i>° of Ag<sub>3</sub>Sn: –21238, –18763 J mol<sup>–1</sup>, and 187.5 J K<sup>–1</sup> mol<sup>–1</sup>, respectively.</p>","PeriodicalId":12781,"journal":{"name":"Geochemistry International","volume":"63 2","pages":"183 - 189"},"PeriodicalIF":0.7,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143778057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Giant iceberg meltwater increases upper-ocean stratification and vertical mixing
IF 18.3 1区 地球科学
Nature Geoscience Pub Date : 2025-04-04 DOI: 10.1038/s41561-025-01659-7
Natasha S. Lucas, J. Alexander Brearley, Katharine R. Hendry, Theo Spira, Anne Braakmann-Folgmann, E. Povl Abrahamsen, Michael P. Meredith, Geraint A. Tarling
{"title":"Giant iceberg meltwater increases upper-ocean stratification and vertical mixing","authors":"Natasha S. Lucas, J. Alexander Brearley, Katharine R. Hendry, Theo Spira, Anne Braakmann-Folgmann, E. Povl Abrahamsen, Michael P. Meredith, Geraint A. Tarling","doi":"10.1038/s41561-025-01659-7","DOIUrl":"https://doi.org/10.1038/s41561-025-01659-7","url":null,"abstract":"<p>Ice-sheet mass loss is one of the clearest manifestations of climate change, with Antarctica discharging mass into the ocean via melting or through calving. The latter produces icebergs that can modify ocean water properties, often at great distances from source. This affects upper-ocean physics and primary productivity, with implications for atmospheric carbon drawdown. A detailed understanding of iceberg modification of ocean waters has hitherto been hindered by a lack of proximal measurements. Here unique measurements of a giant iceberg from an underwater glider enable quantification of meltwater effects on the physical and biological processes in the upper layers of the Southern Ocean, a region disproportionately important for global heat and carbon sequestration. Iceberg basal melting erodes seasonally produced winter water layer stratification, normally forming a strong potential energy barrier to vertical exchange of surface and deep waters, while freshwater run-off increases and shoals near-surface stratification. Nutrient-rich deeper waters, incorporating meltwater loaded with terrigenous material, are ventilated to below this stratification maxima, providing a potential mechanism for alleviating critical phytoplankton-limiting components. Regional historical hydrographic data demonstrate similar stratification changes during the passage of another large iceberg, suggesting that they may be an important pathway of aseasonal winter water modification.</p>","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"25 1","pages":""},"PeriodicalIF":18.3,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143775434","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}
引用次数: 0
Lu-Hf dating of apatite from the Katanga Copperbelt: age resetting due to post-orogenic fluid migration
IF 4.8 2区 地球科学
Mineralium Deposita Pub Date : 2025-04-04 DOI: 10.1007/s00126-025-01359-7
Qiuping Liu, Pascal Mambwe, Stijn Glorie, Philippe Muchez
{"title":"Lu-Hf dating of apatite from the Katanga Copperbelt: age resetting due to post-orogenic fluid migration","authors":"Qiuping Liu, Pascal Mambwe, Stijn Glorie, Philippe Muchez","doi":"10.1007/s00126-025-01359-7","DOIUrl":"https://doi.org/10.1007/s00126-025-01359-7","url":null,"abstract":"<p>The Katanga Copperbelt stands out as one of the world’s largest sediment-hosted Cu-Co provinces, contributing to over 68% of global Co and 15% of global Cu production. The age of these sedimentary Cu-Co deposits remains contentious. This paper presents the first Lu-Hf dates for apatite samples from the late diagenetic to syn-orogentic mineralization phase at Luiswishi, yielding ages of ca. 475–470 Ma. This age range is comparable with a previous Re-Os age on bornite (473 ± 4 Ma) from Kamoto and Rb–Sr and Re–Os ages for sulfides (451 ± 6.0 and 450 ± 3.4 Ma) from Kipushi but younger than the hydrothermal diagenetic mineralization (~ 800 Ma) and the mineralization event related to the Lufilian Orogeny (~ 560–500 Ma). The new Lu-Hf ages indicate a post-orogenic fluid migration at ca. 475–470 Ma in the Katanga Copperbelt, causing dissolution and reprecipitation of apatite and likely precipitation of cogenetic sulfides. The rare earth element (REE) contents of the apatite and scanning electron microprobe (SEM) images provide evidence of partial or complete remobilization of earlier high REE-rich to neo-crystalline homogeneous apatite with lower REE content.</p>","PeriodicalId":18682,"journal":{"name":"Mineralium Deposita","volume":"108 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143775695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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