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Caught in the act: calcareous algae creating undescribed morphologies of mesophotic algal reef 被捕获的行为:钙质藻类创造了未描述的中囊藻礁形态
IF 2.2 3区 地球科学
Marine Geology Pub Date : 2025-08-27 DOI: 10.1016/j.margeo.2025.107644
Sara Innangi , Valentina Alice Bracchi , Daniela Basso , Renato Tonielli
{"title":"Caught in the act: calcareous algae creating undescribed morphologies of mesophotic algal reef","authors":"Sara Innangi ,&nbsp;Valentina Alice Bracchi ,&nbsp;Daniela Basso ,&nbsp;Renato Tonielli","doi":"10.1016/j.margeo.2025.107644","DOIUrl":"10.1016/j.margeo.2025.107644","url":null,"abstract":"<div><div>The exploration of the Linosa Island shelf (Sicily Channel, Mediterranean Sea) by remotely operated vehicle surveys revealed a previously undescribed morphotype of coralligenous algal reef. These biogenic solid substrates are characterized by planar to conical shapes, ranging from single to multilayered structures, with an elevation of 20–30 cm and a concave to convex arrangement. Such coralligenous assemblages primarily cover the seafloor at depths between 80 and 100 m, developing on a sedimentary substrate rich in biogenic components, particularly abundant rhodoliths. We document the role of crustose coralline algae as autogenic engineers, in transforming mobile biogenic sediments into stable substrates by algal reef formation, as theorized by benthic bionomics for the <em>coralligène de plateau</em>.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"490 ","pages":"Article 107644"},"PeriodicalIF":2.2,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144989508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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
Storm sediment deposit from Ko Phra Thong, Thailand 风暴沉积物在泰国的Ko Phra Thong
IF 2.2 3区 地球科学
Marine Geology Pub Date : 2025-08-24 DOI: 10.1016/j.margeo.2025.107641
C. Gouramanis , Y.T. Yan , Z. Yang , J.L. Soria , W. Yap , K. Jankaew , A.D. Switzer
{"title":"Storm sediment deposit from Ko Phra Thong, Thailand","authors":"C. Gouramanis ,&nbsp;Y.T. Yan ,&nbsp;Z. Yang ,&nbsp;J.L. Soria ,&nbsp;W. Yap ,&nbsp;K. Jankaew ,&nbsp;A.D. Switzer","doi":"10.1016/j.margeo.2025.107641","DOIUrl":"10.1016/j.margeo.2025.107641","url":null,"abstract":"<div><div>Siliciclastic storm deposits have been described from coastlines around the world over the last six decades. Most of these storm deposits are formed from storms directly or obliquely making landfall, or tangentially bypassing nearby coastal systems. In these instances, coastal water piles up on the coast as the storm approaches the coastline before breaching or overtopping the beach barrier. Seldom have storm deposits been examined from coastlines on the lee of the storm. We describe the sedimentary and stratigraphical variation of a small storm fan from three short sediment cores from Ko Phra Thong, western Thailand. The fan was formed after a tropical depression crossed the Malay-Thai peninsula in May 2007, resulting in water piling up along the coast and breaching of the small berm on the western coastline of Ko Phra Thong. Sufficient accommodation space resulted in fine to medium quartz and heavy-mineral rich sands to be deposited upon the back beach sediments. The basal contact consists of a soil horizon above beach sands with an abundance of <em>Casuarina equisetifolia</em> needles. Horizontal laminations of heavy minerals characterise the lowest stratigraphic unit, conformably overlain by a massive unit which is in turn overlain by a unit with vertical and sub-horizontal root structures. At the landward extremity of the fan, faint landward dipping cross beds are observed, indicative of terminal foresets. As Ko Phra Thong preserves a well-established history of past tsunami sand washover deposits, the presence of a storm overwash fan along this coast complicates the inferred overwash event history. This complication is particularly pertinent when the palaeo-shoreline was closer to the swales where smaller, lower energy events, such as storms, can overtop the palaeo-berm and deposit sandy units. This most likely occurred between 2500 and 2000 years ago when thin, structureless sandy deposits were emplaced near the palaeo-shoreline.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"489 ","pages":"Article 107641"},"PeriodicalIF":2.2,"publicationDate":"2025-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144908855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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
Observations of oscillatory and unidirectional flow dynamics over a limestone reef 石灰岩礁上振荡和单向流动动力学的观测
IF 2.2 3区 地球科学
Marine Geology Pub Date : 2025-08-24 DOI: 10.1016/j.margeo.2025.107640
Freya Barr , Charlotte F.K. Uphues , Graziela Miot da Silva , Patrick A. Hesp
{"title":"Observations of oscillatory and unidirectional flow dynamics over a limestone reef","authors":"Freya Barr ,&nbsp;Charlotte F.K. Uphues ,&nbsp;Graziela Miot da Silva ,&nbsp;Patrick A. Hesp","doi":"10.1016/j.margeo.2025.107640","DOIUrl":"10.1016/j.margeo.2025.107640","url":null,"abstract":"<div><div>Natural and human made reef structures provide effective coastal protection by attenuating incident wave and current energy. Anticipated effects of climate change, such as sea level rise, threaten coastal zones and are predicted to reduce the protection provided to coastlines by reef structures. This study aims to investigate wave and current dynamics at a limestone reef site at Robe, South Australia, to improve our understanding of how limestone reefs act as protective reef structures in present-day and in changing climate conditions. Pressure sensors and acoustic doppler current profilers were deployed on a cross-reef transect to investigate rates of wave attenuation, shifts in spectral wave energy, and changes to current speed and direction. Field measurements indicate that the Town Beach reef acts as a tidally modulated low-pass filter, attenuating more wave energy at lower water levels compared to higher water levels. Despite attenuating less wave energy than other reported studies, the Town Beach reef effectively dissipates approximately 42 % of gravity wave energy, resulting in a domination of lower frequency, infragravity wave energy within the landward reef-protected lagoon. Current speeds landward of the reef are approximately one third lower than those observed seaward of the reef. Bidirectional flows (north-south and east-west, respectively) occur at higher water levels, changing to unidirectional flows (south and west, respectively) at lower water levels. Potential reasons for these observed dynamics are discussed, and future research is proposed to address key limitations, such as unknown ecological, geometric, and morphologic aspects of the reef.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"489 ","pages":"Article 107640"},"PeriodicalIF":2.2,"publicationDate":"2025-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144912753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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
Application potential of UK′37 and TEX86H palaeothermometers in high-energy strait-type marginal seas: a case study in the Taiwan Strait UK’37和TEX86H古地温计在高能海峡型边缘海的应用潜力——以台湾海峡为例
IF 2.2 3区 地球科学
Marine Geology Pub Date : 2025-08-22 DOI: 10.1016/j.margeo.2025.107639
Chang Ran , Shuqin Tao , Mengyuan Wang , Zhen Jiang , Xiang Ye , Aijun Wang
{"title":"Application potential of UK′37 and TEX86H palaeothermometers in high-energy strait-type marginal seas: a case study in the Taiwan Strait","authors":"Chang Ran ,&nbsp;Shuqin Tao ,&nbsp;Mengyuan Wang ,&nbsp;Zhen Jiang ,&nbsp;Xiang Ye ,&nbsp;Aijun Wang","doi":"10.1016/j.margeo.2025.107639","DOIUrl":"10.1016/j.margeo.2025.107639","url":null,"abstract":"<div><div>U<sup>K’</sup><sub>37</sub> and TEX<sub>86</sub><sup>H</sup> palaeothermometers are widely applied to sea surface temperature (SST) reconstructions in global oceans. However, their applications in marginal seas often yields biased results due to regional environmental factors. This study investigated the applicability and controlling factors of these proxies in the subtropical, high-energy Taiwan Strait (TS). Utilizing a 35-year dataset (1982–2016) of AVHRR and MODIS-derived annual and seasonal average SST archives, we conducted regression analyses on U<sup>K’</sup><sub>37</sub> and TEX<sub>86</sub><sup>H</sup> proxies of 58 surface sediment samples from the study area. Additionally, we employed Empirical Orthogonal Function (EOF) analysis to elucidate the physical processes influencing the index reliability. TEX<sub>86</sub><sup>H</sup>-reconstructed SSTs exhibit a cold bias of −5.5–0.3 °C compared to observed SSTs, largely due to seasonal upwelling and terrestrial inputs. Conversely, U<sup>K’</sup><sub>37</sub>-reconstructed SST in the muddy sediment zone of the northern TS shows a warm bias of 1.8–6.3 °C, relative to observed SST, attributable to lateral transport processes in the said environment. By accounting for terrestrial influences as the main non-temperature factor, we developed an improved regional calibration equation for TEX<sub>86</sub><sup>H</sup>-SST in the TS. These results highlight the necessity of considering hydrodynamic effects when applying U<sup>K’</sup><sub>37</sub> index in such marginal seas. Through modern calibration using surface suspended particulate matter (SPM) and hydrodynamic correction, this study effectively mitigates lateral transport interference, providing a robust framework for palaeotemperature reconstruction in strong hydrodynamic strait-type marginal sea environments.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"489 ","pages":"Article 107639"},"PeriodicalIF":2.2,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144931797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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
A thousand-year journey of lithification: CT-analysis and radiocarbon dating of algal reef from Central Mediterranean 一千年的岩化之旅:地中海中部藻礁的ct分析和放射性碳定年
IF 2.2 3区 地球科学
Marine Geology Pub Date : 2025-08-21 DOI: 10.1016/j.margeo.2025.107637
Pietro Bazzicalupo , Valentina Alice Bracchi , Mara Cipriani , Adriano Guido , Antonietta Rosso , Rossana Sanfilippo , Francesco Maspero , Anna Galli , Elena de Ponti , Daniela Basso
{"title":"A thousand-year journey of lithification: CT-analysis and radiocarbon dating of algal reef from Central Mediterranean","authors":"Pietro Bazzicalupo ,&nbsp;Valentina Alice Bracchi ,&nbsp;Mara Cipriani ,&nbsp;Adriano Guido ,&nbsp;Antonietta Rosso ,&nbsp;Rossana Sanfilippo ,&nbsp;Francesco Maspero ,&nbsp;Anna Galli ,&nbsp;Elena de Ponti ,&nbsp;Daniela Basso","doi":"10.1016/j.margeo.2025.107637","DOIUrl":"10.1016/j.margeo.2025.107637","url":null,"abstract":"<div><div>Calcareous algal reefs are Mediterranean carbonate structures, formed by coralline red algae, that display early lithification and preserve key geobiological records. These structures exhibit complex three-dimensional frameworks influenced by environmental conditions and biological interactions, but their lithification processes, porosity evolution, and long-term growth patterns remain poorly understood. In this study, we use Computed Tomography (CT) scanning and radiocarbon dating on four coralligenous build-ups collected along a depth gradient offshore Marzamemi, SE Sicily, to investigate internal skeletal density, porosity distribution, and age profiles. Our findings reveal that lithification progresses gradually from High-Density (HD) to Ultra-High-Density (UHD) material, correlating inversely with porosity. Radiocarbon dating indicates a lithification timeline of roughly 1000 years, with the oldest, densest material dating back over 5000 years. The structures demonstrate a depth-density and age-depth gradient: deeper and older build-ups exhibited higher quantity of UHD material, whereas younger, shallower build-ups contain a higher proportion of HD material. Additionally, evidence suggests that specific build-ups may have been fragmented and relocated due to environmental or anthropogenic factors, further influencing growth patterns. The CT-analysis contributes to improving knowledge on coralligenous reef formation and evolution, underscoring the role of lithification in maintaining structural stability over millennia and providing insights applicable to the study of fossil reef systems.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"489 ","pages":"Article 107637"},"PeriodicalIF":2.2,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144908901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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
Sediment provenance shifts in the South Yellow Sea: Implications of reduced river discharges over the past 60 years 南黄海沉积物物源转移:过去60年河流流量减少的影响
IF 2.2 3区 地球科学
Marine Geology Pub Date : 2025-08-20 DOI: 10.1016/j.margeo.2025.107638
Jian Lu , Anchun Li , Jin Zhang , Xiaochuan Ma
{"title":"Sediment provenance shifts in the South Yellow Sea: Implications of reduced river discharges over the past 60 years","authors":"Jian Lu ,&nbsp;Anchun Li ,&nbsp;Jin Zhang ,&nbsp;Xiaochuan Ma","doi":"10.1016/j.margeo.2025.107638","DOIUrl":"10.1016/j.margeo.2025.107638","url":null,"abstract":"<div><div>The Yellow River and Yangtze River significantly influence the South Yellow Sea (SYS) through sediment discharges. Over the past several decades, sediment loads from these rivers into the sea have dramatically decreased due to climate change and intensified human activities. However, there is limited understanding of how this reduction in river discharge might affect the provenance of sediments in the SYS. To address this, surface sediment samples were collected at identical stations in the SYS during two periods: 1958 and 2012. Grain size analysis revealed notable differences: in 2012, clay content decreased, and silt increased, resulting in coarser sediments compared to 1958. Provenance analysis revealed that the fine-grained surface sediments in the SYS were primarily derived from the Yellow and Yangtze Rivers, as evidenced by clay mineral compositions (illite, smectite, kaolinite, and chlorite) and element ratios (Ti/Al vs. Ti/Zr, and Ti/Zr vs. La/Hf). Interestingly, despite reduced sediment loads, the influence of the Yellow River expanded, while the influence of the Yangtze River decreased between 1958 and 2012. These changes in provenance are attributed to differences in sediment transport mechanisms from each source to the SYS. Reduced Yangtze sediment load led to decreased deposition off the Jiangsu coast during summer, limiting Yangtze-derived sediments in the SYS during winter. Conversely, resuspended sediments from the modern and old Yellow River subaqueous deltas provided continuous supply of material to the SYS. This study provides valuable insights into source-to-sink processes in marginal seas, particularly as global rivers continue to experience reductions in sediment discharge.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"489 ","pages":"Article 107638"},"PeriodicalIF":2.2,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144889147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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
Micro-Erosion Meter derived downwearing rates on inter-tidal shore platforms at Māhia Peninsula, New Zealand: Implications for uplifted rock coasts 微侵蚀仪在Māhia半岛潮汐间海岸平台上得出的下降速率,新西兰:对隆起的岩石海岸的影响
IF 2.2 3区 地球科学
Marine Geology Pub Date : 2025-08-11 DOI: 10.1016/j.margeo.2025.107636
Jokotola Omidiji , Wayne Stephenson , Mark Dickson , Kevin Norton
{"title":"Micro-Erosion Meter derived downwearing rates on inter-tidal shore platforms at Māhia Peninsula, New Zealand: Implications for uplifted rock coasts","authors":"Jokotola Omidiji ,&nbsp;Wayne Stephenson ,&nbsp;Mark Dickson ,&nbsp;Kevin Norton","doi":"10.1016/j.margeo.2025.107636","DOIUrl":"10.1016/j.margeo.2025.107636","url":null,"abstract":"<div><div>Downwearing rates obtained from tectonically active coasts provide evidence of rapid rock breakdown following coseismic uplift. These measurements help solve puzzles about ‘missing' marine terraces and have implications for accurate reconstruction of past sea levels, earthquakes and rock coast evolution. However, very few detailed erosion datasets exist for uplifted shore platforms, making it uncertain if erosion records from one coast can be extrapolated to other regions with similar tectonic, geologic, or geomorphic characteristics. Here we present new downwearing rates from an inter-tidal mudstone shore platform at Kahutara Point, Māhia Peninsula, New Zealand that was uplifted likely by ∼3 m within the last 300 years. Downwearing rates were measured over 49 months/4.05 years using the Micro-Erosion Meter (MEM) and Structure-from-Motion photogrammetry: the mean annual downwearing rate was 1.08 mm yr<sup>−1</sup>, while the total erosion at individual MEM stations ranged from 0.44 to 14.37 mm (equivalent to mean downwearing rates of 0.11 to 3.54 mm yr<sup>−1</sup>). Orthophotographs of the eroded rock surfaces indicate the combined role of marine processes (waves and tides), sub-aerial weathering processes, salt weathering and biological activity in the erosion of the mudstone platform surface. The downwearing rates from Kahutara Point, Māhia Peninsula are statistically similar to previously published downwearing rates (1.23 mm yr<sup>−1</sup>) from mudstone platforms at Kaikōura Peninsula, New Zealand, that were obtained prior to the 2016 Kaikōura earthquake, but are significantly different from perturbed post-uplift downwearing rates (2.25 mm yr<sup>−1</sup>) obtained from the same MEM stations following coseismic uplift of ∼1 m. This work provides valuable data to support comparison of the development of shore platforms and marine terraces at Kaikōura and Māhia at different stages of their tectonic evolution.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"489 ","pages":"Article 107636"},"PeriodicalIF":2.2,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144841638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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
Geochemistry of surface sediments from ultra-slow spreading eastern SWIR 63°E–69°E: Inferences on hydrothermal signatures 超慢扩张SWIR东部63°E - 69°E表层沉积物地球化学:热液特征的推断
IF 2.2 3区 地球科学
Marine Geology Pub Date : 2025-08-09 DOI: 10.1016/j.margeo.2025.107633
Deepak K. Agarwal , Parijat Roy , Esha Gadekar , John Kurian Palayil
{"title":"Geochemistry of surface sediments from ultra-slow spreading eastern SWIR 63°E–69°E: Inferences on hydrothermal signatures","authors":"Deepak K. Agarwal ,&nbsp;Parijat Roy ,&nbsp;Esha Gadekar ,&nbsp;John Kurian Palayil","doi":"10.1016/j.margeo.2025.107633","DOIUrl":"10.1016/j.margeo.2025.107633","url":null,"abstract":"<div><div>The seawater precipitation, hydrothermal input (plume-derived or weathered sulfide), and weathering of nearby rock outcrops constrain the dominant end-member components in the mid-ocean ridge (MOR) sediments. We have conducted mineralogical, geochemical, and statistical studies of surface sediments from the eastern part of the ultra-slow spreading Southwest Indian Ridge (SWIR) 63°E–69°E. Further, we combined factor analysis and linear regression to demonstrate how relative enrichment/depletion of certain elements compared to the general regional sediment composition can constrain the local seafloor processes. Mineralogy and factor analysis of the carbonate-free geochemical data reveal that the sediments consist of three main end-members with respect to Al, Ti, Mg, Fe, Mn, K, Rb, Cu, Zn, V, Cr, Ni, and As; the end-members are mixed in different proportions in the sediments. The three endmember components, authigenic hydrothermal minerals – Fe-Mn-(oxyhydr)oxides, bernessite, and hematite; basaltic detritus – Labradorite and alteration products (montmorillonite, vermiculite, and illite); and ultramafic detritus – antigorite, account for 62.3 %, 21.8 %, and 10.2 % of the elemental variance, respectively. We also used Ti/Al vs Cr/Al and Ni/Al proxies to show that some samples consist of ultramafic and serpentinized detritus. The sediment sample C-GC-16(0-1 cm) at 67.260° E, 26.574° S, consists of relatively high conservative and redox-sensitive elements (U, Mo, V, As), alkali metals (K, Rb, Cs), and Cu, reflecting the presence of a hydrothermal source in the near vicinity. Moreover, linear relations reveal the relative scavenging of REEs from the seawater by Fe-Mn-(oxyhydr)oxides, which are recorded by Ce anomaly and REE fractionation values relative to Fe and Mn content.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"489 ","pages":"Article 107633"},"PeriodicalIF":2.2,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144841637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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
Sedimentary processes in transport-limited versus weathering-limited erosional regimes: Contrasting mineralogical and geochemical signatures of sand and mud in Hainan and Taiwan islands 运输受限和风化受限侵蚀机制下的沉积过程:海南和台湾岛内砂泥的矿物学和地球化学特征对比
IF 2.2 3区 地球科学
Marine Geology Pub Date : 2025-08-08 DOI: 10.1016/j.margeo.2025.107635
Jie He , Eduardo Garzanti , Tao Jiang , Entao Liu , Marta Barbarano , Alberto Resentini , Hua Wang
{"title":"Sedimentary processes in transport-limited versus weathering-limited erosional regimes: Contrasting mineralogical and geochemical signatures of sand and mud in Hainan and Taiwan islands","authors":"Jie He ,&nbsp;Eduardo Garzanti ,&nbsp;Tao Jiang ,&nbsp;Entao Liu ,&nbsp;Marta Barbarano ,&nbsp;Alberto Resentini ,&nbsp;Hua Wang","doi":"10.1016/j.margeo.2025.107635","DOIUrl":"10.1016/j.margeo.2025.107635","url":null,"abstract":"<div><div>This study provides and discusses an integrated petrographic, heavy-mineral, clay-mineral, elemental-geochemistry and Sr-Nd isotope-geochemistry dataset on sand and mud transported by mountain rivers in Hainan Island, where sand composition is mainly feldspatho-quartzose to quartz-rich feldspatho-quartzose, with K-feldspar invariably prevailing over plagioclase. Illite associated with chlorite prevails in the west, whereas kaolinite prevails in the north and northeast, underscoring a gradient of eastward-increasing weathering intensity in close correspondence with the progressive eastward increase in monsoonal rainfall.</div><div>All sand samples are enriched in SiO<sub>2</sub> relative to the upper continental crust and consequently depleted in most other chemical elements. The order of element mobility indicated by α<sup>Al</sup> values is Mg &gt; Ca &gt; Na &gt; Sr &gt; K ≈ Ba ≈ Rb. The <sup>87</sup>Sr/<sup>86</sup>Sr ratio varies between 0.717 and 0.721, and εNd ranges from −6.7 to −9.6. Moderately negative εNd and relatively high <sup>87</sup>Sr/<sup>86</sup>Sr point at a significant contribution from old crystalline basement, directly or through recycling of siliciclastic strata.</div><div>Two endmember types of short river systems can be distinguished in eastern Asia, one dominated by chemical weathering controlled by tropical monsoonal climate under a tectonically stable background and gentle topography (transport-limited regime, dominant in Hainan Island) and another dominated by provenance-controlled physical erosion under a tectonically active background and rugged topography (weathering-limited regime, dominant in Taiwan Island). Mineralogical and geochemical information obtained from river sediments in these contrasting regimes can be profitably used in paleo-climatic inferences and reconstructions.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"489 ","pages":"Article 107635"},"PeriodicalIF":2.2,"publicationDate":"2025-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144826359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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
Intelligent prediction of sediment floc settling velocity: Employing explainable machine learning and quantifying the impacts of environmental factors 泥沙沉降速度的智能预测:采用可解释的机器学习和量化环境因素的影响
IF 2.2 3区 地球科学
Marine Geology Pub Date : 2025-08-05 DOI: 10.1016/j.margeo.2025.107631
Jinglun Huang, Zhixin Cao, Leiping Ye, Jie Ren, Jiaxue Wu
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