Marine Geology最新文献

{"title":"Hydrothermal plume events in a 40 kyr sediment record from the flanks of the Southwest Indian Ridge","authors":"Bei Song ,&nbsp;Shihui Lv ,&nbsp;Xin Su ,&nbsp;Xuan Ding ,&nbsp;Chunhui Tao ,&nbsp;Chonghan Yu ,&nbsp;Jie Zhang ,&nbsp;Xuezhen Li","doi":"10.1016/j.margeo.2025.107659","DOIUrl":"10.1016/j.margeo.2025.107659","url":null,"abstract":"<div><div>Hydrothermal plumes play a critical role in chemical fluxes and element transport in the oceans. However, the impact on the sediments along mid-ocean ridge flanks is not well constrained. In this study, samples from three sediment cores (MC03/04/05) were analyzed for their geochemical records located at the Southwest Indian Ridge (SWIR) flanks over the past 40 ka. In addition to the dominant CaO content, these flank sediments show elevated concentrations of Fe, Mn, Cu, Zn, and REEs with positive Y anomalies. We also constructed two geochemical diagrams (Cu/Zn-Mn/Fe-REE/Fe and REE/Fe vs. Mn/Fe) to identify hydrothermal plume inputs. Based on these results, we revealed four distal plume events at 32–30 ka (MC04), 16–14 ka (MC05), 10–8 ka (MC05), and 7.5–6.5 ka (MC03). Furthermore, cluster analysis indicates that these plume events originated from the Yuhuang Hydrothermal Field (YHF), and they correspond temporally to periods of sulfide formation within the field. Finally, we propose that the YHF plume dispersion was coupled with the Agulhas Return Current (ARC) migration, resulting in the following processes: (1) 32–30 ka southward ARC transported plume material to MC04; (2) 16–14 ka and 10–8 ka northward shifts deposited plume fallout at MC05; (3) 7.5–6.5 ka southward ARC movement led to MC03 deposition. Our findings reveal metal (Fe, Mn, REE) transport mechanisms from the SWIR axial zones to distal flanks, highlighting plume-ARC interactions over millennial timescales.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"490 ","pages":"Article 107659"},"PeriodicalIF":2.2,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145154930","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}

{"title":"The impact of mangroves development and morphodynamics on channel function shift and flow asymmetry in an estuarine channel-shoal system","authors":"Amin Rahdarian ,&nbsp;Karin R. Bryan ,&nbsp;Mick Van Der Wegen","doi":"10.1016/j.margeo.2025.107658","DOIUrl":"10.1016/j.margeo.2025.107658","url":null,"abstract":"<div><div>Estuarine channels convey tidal flow and sediments, while the direction and magnitude of tide-residual transports largely depends on the surrounding estuarine bathymetry, shoals and vegetation cover. This study explores the controls of historic morphodynamics, mangrove development and channels on landscape-scale tidal hydrodynamics around a mangrove-covered estuarine shoal in Whitianga estuary, Aotearoa New Zealand. A Delft3D hydrodynamic model was used to explore the impact of historic developments on spatial flow patterns and flow asymmetry based on an analysis of historical images of the site including conditions of the mangrove forest in the 1940s.</div><div>Model results clearly reveal areas of ebb and flood dominance in the model domain, where mangrove surrounded creeks are ebb dominant and shoal incising channels are flood dominant. Within the forest, the seaward part of mangroves is ebb-dominant, whereas a flood-dominance function in the back of the forest with higher elevated mangroves is mostly observed. Removing vegetation leads to a large-scale change in flow routing and flow asymmetry, whereas if creeks are infilled, local changes only around the location of the creeks are observed.</div><div>The movement of fine sediment fractions is inferred by the slack water duration at high tide. The existence of vegetation affects the cohesive fraction. Without vegetation, the slack water duration becomes shorter on the shoal close to the fringe, inside and the edge of the former forest while it becomes longer inside the river channel and on the edge of the shoal close to the river channel. In the scenario that channels were infilled, a longer (shorter) slack water duration at the mouth and head of channels and inside channels (around the channels) were observed.</div><div>Expansion of mangroves can cause a function shift of the channels. Model results suggest that the ebb-dominant modern-day mangrove creek was flood-dominant in 1940s prior to colonization of mangroves in the inner bend of the shoal.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"490 ","pages":"Article 107658"},"PeriodicalIF":2.2,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096739","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}

{"title":"Reconstruction of oceanographic and climatic changes over the past ∼ 600 years over Coquimbo Bay, Chile (30°S)","authors":"Karen Araya ,&nbsp;Práxedes Muñoz ,&nbsp;Antonio Maldonado ,&nbsp;Laurent Dezileau ,&nbsp;Lorena Rebolledo ,&nbsp;Gloria Sanchez ,&nbsp;Gabriel Cantarutti","doi":"10.1016/j.margeo.2025.107642","DOIUrl":"10.1016/j.margeo.2025.107642","url":null,"abstract":"<div><div>The upwelling system off Coquimbo (30°S) is strongly influenced by interannual variability driven by the El Niño-Southern Oscillation (ENSO), which decreases primary productivity and increases precipitation during the warm phase (El Niño events). This study examined the historical variations in the primary oceanographic and climatic characteristics of the region based on recent sedimentary records from Coquimbo Bay. In a sediment core (BC117; 83 cm), nine sedimentary units were identified and categorized into two groups: u1, u3, u5, and u9 represent marine sedimentation, as indicated by the major contribution of marine diatoms and higher δ¹³C and δ¹⁵N values reflecting marine conditions. In contrast, u4, u6 and u7 exhibited more depleted δ¹³C values and an increase in freshwater diatom valves, suggesting a significant continental influence, likely from alluvial events. These units showed elevated concentrations of Fe, K, and Cu and an increase in fine sediment content, likely associated with El Niño-induced heavy rainfall around 1700–1730 CE. This period was followed by a decrease in continental input owing to reduced pluviosity. Spanning from 1403 CE to 1850 CE, the core reflects a period dominated by La Niña-like conditions, sustained by an intensified Southern Oscillation Index (SOI) and diminished Interdecadal Pacific Oscillation (IPO). During this period, the seafloor experienced an increase in reduced conditions, likely leading to anoxic environments, which were subsequently followed by less reduced conditions encompassing the Current Warm Period (CWP) due to enhanced ventilation processes. Nevertheless, increasing proxies for primary productivity have suggested an intensification of upwelling in recent times. Based on the characteristics of the units, three tsunami events were characterized by a significant reduction in total diatom counts contingent on the energy of the event and a sharp basal contact between the lower undisturbed unit and the very disturbed overlying layer (1420, 1471, and 1751 CE).</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"490 ","pages":"Article 107642"},"PeriodicalIF":2.2,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220425","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}

{"title":"Did Globigerinoides ruber (pink) disappear entirely from the Indian Ocean after 120 kyr BP?","authors":"Ammoose K. Jayan ,&nbsp;A.V. Sijinkumar ,&nbsp;Kaustubh Thirumalai ,&nbsp;Lael Vetter ,&nbsp;P. John Kurian ,&nbsp;A. Prajith ,&nbsp;Rajveer Sharma","doi":"10.1016/j.margeo.2025.107656","DOIUrl":"10.1016/j.margeo.2025.107656","url":null,"abstract":"<div><div>Extant since the Miocene, <em>Globigerinoides ruber</em> is a mixed-layer planktic foraminiferal species, cosmopolitan to the tropical–subtropical oceans. <em>Globigerinoides ruber</em> has multiple morphotypical variants with distinctive white and pink chromotypes. Today, the pink variety is exclusively found in the Atlantic Ocean and its nearby basins. For the past few decades, it was believed that pink-pigmented <em>G. ruber</em> disappeared from the Indo-Pacific Oceans at about 120 kyr BP. However, a recent study from the northwestern Bay of Bengal documented the presence of <em>G. ruber</em> (pink) in surface sediments. Hitherto, there was no evidence of <em>G. ruber</em> (pink) in downcore sediments from the Indian Ocean since 120 kyr BP. In this study, for the first time, we document the re-appearance of <em>G. ruber</em> (pink) from 30 to 8 kyr BP in gravity core MGS30/GC-03. The core was retrieved from the eastern BoB from a water depth of 1883 m, and its chronology was established using eight AMS radiocarbon dates. We observed high abundances of <em>G. ruber</em> (pink) during the Last Glacial Maximum (LGM) and Heinrich Event 1 and 2 (H1 and H2) compared to the Holocene Epoch. Higher abundances of <em>G. ruber</em> (pink) during the LGM were followed by a gradual decrease during the deglaciation and the early Holocene until it disappeared after around 8 kyr BP. Variability in the relative abundance of <em>G. ruber</em> (pink) was compared with mixed-layer and thermocline-dwelling species. The high abundance of <em>G. ruber</em> (pink), <em>N. dutertrei</em> and <em>G. menardii</em> during H2 and LGM in the eastern BoB suggests enhanced NE monsoon-driven vertical mixing, which may have facilitated nutrient transport from deeper layers to the thermocline and photic zone. The presence of <em>G. ruber</em> (pink) during glacial stages and the early Holocene demonstrates that it has not entirely disappeared from the Indian Ocean since 120 kyr BP and that its turnover may be driven by changing hydrographic conditions.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"490 ","pages":"Article 107656"},"PeriodicalIF":2.2,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096740","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}

{"title":"Distribution of biochemical components in sedimentary organic matter of a Coastal Wetland: Anthropogenic and detrital influences","authors":"Eleonora M. Fernández ,&nbsp;Carla V. Spetter ,&nbsp;Mariana Gentile ,&nbsp;Diana M. Villagrán ,&nbsp;Ana M. Martínez ,&nbsp;Natalia S. Buzzi","doi":"10.1016/j.margeo.2025.107657","DOIUrl":"10.1016/j.margeo.2025.107657","url":null,"abstract":"<div><div>Coastal wetlands, particularly tidal flats, play a crucial role in carbon sequestration and nutrient cycling in temperate environments. This study investigates the biochemical composition of sedimentary organic matter (SOM) in the tidal flats of Puerto Rosales (Bahía Blanca Estuary, Argentina), emphasizing the dual influences of natural processes and anthropogenic activities. Sampling was conducted seasonally (2014–2015) at two sites: ST1, an intertidal zone affected by untreated sewage discharge, and ST2, a supratidal zone dominated by microbial mats. Surface (0–5 mm) and subsurface (5–10 mm) sediment layers were analyzed to assess early diagenetic processes, SOM component and trophic status. Results indicated that the organic carbon (OC) in sediments was predominantly non-biogenic, with proteins as the major component of the labile fraction, influenced by seasonal phytoplankton blooms and urban discharges. While the tidal flat exhibited meso-oligotrophic to eutrophic conditions, refractory material dominated over labile fractions (proteins and carbohydrates). Additionally, distinct spatial and seasonal variations in SOM quality and composition, linked to redox conditions and organic detrital quality were observed.These findings underscore the ecological importance of Puerto Rosales tidal flats as dynamic systems for carbon storage and nutrient recycling. They highlight the need for sustainable management strategies to mitigate anthropogenic pressures and preserve the critical ecosystem functions of these coastal wetlands.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"490 ","pages":"Article 107657"},"PeriodicalIF":2.2,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096742","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}

{"title":"Submarine channel shape controls combined turbidity current–contour current flow","authors":"P.H. Adema ,&nbsp;J.T. Eggenhuisen ,&nbsp;R. Silva Jacinto ,&nbsp;N. Lagunova ,&nbsp;A.I. Alwadhakhi ,&nbsp;R. van der Woning ,&nbsp;E. Miramontes","doi":"10.1016/j.margeo.2025.107646","DOIUrl":"10.1016/j.margeo.2025.107646","url":null,"abstract":"<div><div>Turbidity currents transport sediment, organic carbon, nutrients, and pollutants from the continental shelf to the deep sea. They can flow over hundreds of kilometers through submarine canyons and channels. Along their trajectory, these flows may interact with contour currents, creating a mixed turbidite–contourite depositional system. Examples of such systems in the oceans exhibit a variety of channel shapes that are often asymmetrical. The effect of channel shape on turbidity currents and their interaction with contour currents remains unclear, yet understanding this could link flow characteristics to seafloor morphology. To this end, purely gravity-driven flows (turbidity currents) and combined flows were simulated in five different channel shapes (three symmetrical and two asymmetrical). The experiments show that firstly, combined flows have less steep vertical velocity gradients than purely gravity-driven experiments. The contour current advects momentum of the turbidity currents out of the channel onto the overbank, reducing the downslope flow velocity in the channel. Secondly, channel asymmetry results in asymmetrically overspilling flows, even without a contour current. Specifically, the overspilling flow is thicker and faster over the steep channel margin than over the gentle margin. Lastly, two types of secondary flow cells were formed. Channel cells, which are confined to the channel, and front cells, which form near stationary fronts in combined flows. These findings suggest that channel asymmetry alone is not diagnostic for inferring paleo-contour current directions. However, channel asymmetry can help to infer velocity distributions inside channels when only bathymetric data is available.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"490 ","pages":"Article 107646"},"PeriodicalIF":2.2,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145154936","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}

{"title":"Fe-nodules from the southern Baltic Sea: Morphology, mineralogy and geochemistry","authors":"Karol Zglinicki ,&nbsp;Michał Pilaszkiewicz ,&nbsp;Agnieszka Wrzosek ,&nbsp;Krzysztof Szamałek ,&nbsp;Szymon Uścinowicz ,&nbsp;Kazimierz Szefler ,&nbsp;Jarosław Nowak ,&nbsp;Paweł Bylina","doi":"10.1016/j.margeo.2025.107655","DOIUrl":"10.1016/j.margeo.2025.107655","url":null,"abstract":"<div><div>Studies of polymetallic nodules in oceans and shelf seas, including the Baltic Sea, have a long history. However, detailed mineralogical and geochemical data for nodules from the southern Polish Baltic region are limited in comparison to data from oceans and other regions of the Baltic Sea. This study fills gaps in knowledge regarding the mineralogical and chemical composition of nodules from the southern Baltic. The research concerned nodules sampled from two locations in the Polish Exclusive Economic Zone (EEZ), namely seabed elevations between the Słupsk Furrow and Gdańsk Basin (P1) and between Bornholm Basin and Słupsk Furrow (P2), areas known for their abundance of nodules. The following analytical methods were used: X-ray diffraction (XRD), scanning electron microscopy (SEM-EDS), inductively coupled plasma emission spectroscopy/optical emission spectroscopy (ICP-MS/OES) and electron probe microanalysis (EPMA). The nodules comprise a mixture of terrigenous minerals and autochthonous manganese oxides, represented by birnessite, vernadite (7 Å and 10 Å varieties) and iron oxyhydroxides, mainly goethite. Depending on the location, the samples reveal varying chemical compositions. Nodules from sampling site P1 are characterized by a moderate Fe content, averaging 10.68 wt%, and low Mn content, averaging 3.04 wt%, with an Mn/Fe ratio ranging from 0.12 to 0.43. These nodules have low concentrations of ∑Ni + Co + Cu (104.5 to 238.6 ppm) and other economically significant metals such as Zn (78.0–140 ppm), Mo (14.9–77.8 ppm), and V (80.0–187.0 ppm). These nodules exhibit pronounced lithium enrichment, with concentrations ranging from 72.1 to 444.6 ppm. On the other hand, at sampling site P2, the average parameters are higher, i.e., Fe content 12.30 wt%, Mn 10.50 wt%, and a Mn/Fe ratio of 0.50 to 1.25. The concentration of ∑Ni + Co + Cu ranges from 159.0 to 530.0 ppm, with elevated contents of Zn (104.0–238.0 ppm), Mo (26.0–174.0 ppm), and V (118.0–249.0 ppm). Lithium content is low (max. 145.4 ppm). In field P1, the growth rates ranged from 2.21 to 3.47 mm/1000 years, while in field P2, the growth rates ranged from 6.50 to 21.00 mm/1000 years. The genesis of the nodules indicates mixed diagenetic‑hydrogenetic processes probably influenced by hydrothermal activity. Although classical hydrothermal processes do not occur in the Baltic Sea, the impact of deep-seated fluids may significantly shape the formation of the nodules.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"490 ","pages":"Article 107655"},"PeriodicalIF":2.2,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096741","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}

{"title":"Impacts of vegetation replacement on organic carbon burial in coastal wetlands of Sansha Bay, Southeast China","authors":"Jianfeng Su ,&nbsp;Yijing Wu ,&nbsp;Daidu Fan","doi":"10.1016/j.margeo.2025.107647","DOIUrl":"10.1016/j.margeo.2025.107647","url":null,"abstract":"<div><div>Coastal wetlands are essential yet vulnerable carbon sinks; however, the impacts of vegetation replacement on carbon dynamics remain less understood. This study investigates the sources, burial rates, and historical trends of sedimentary organic carbon (OC) across various wetland types, including mangroves, <em>Spartina alterniflora</em> (<em>S. A.</em>), and barren tidal flats in Sansha Bay, Fujian Province, Southeast China. We analyzed sediment cores for geochemical (TOC, TN, δ¹³C) and radionuclide (²¹⁰Pb, ¹³⁷Cs) proxies. Our results reveal that riverine inputs are the primary sources of OC, contributing 51–75 % of the total. The mangrove ecosystem exhibits the highest OC burial rate at163 ± 49 g/m²/yr, followed by the <em>S. A.</em> marshland at 115 ± 16 g/m²/yr, and barren flats at 69 ± 13 g/m²/yr. However, human interventions, particularly land reclamation and the invasion of <em>S. A.</em>, have resulted in a 13.64 % decrease in the bay-wide OC burial rate from 1999 to 2018. While <em>S. A.</em> enhances local carbon sequestration, its invasion disrupts mangrove ecosystems and destabilizes existing carbon pools. This study underscores the dual impact of vegetation changes on coastal carbon dynamics: invasive species may temporarily enhance OC burial rates but ultimately undermine long-term ecosystem resilience. To maintain blue carbon functions, we advocate prioritizing mangrove conservation, restoring degraded wetlands, and curbing the spread of <em>S. A.</em> These findings provide valuable insights for balancing carbon mitigation efforts and biodiversity conservation in rapidly changing coastal environments.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"490 ","pages":"Article 107647"},"PeriodicalIF":2.2,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047016","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}

{"title":"Mabahiss Deep in the Northern Red Sea: New insights from high-resolution bathymetric mapping and analysis","authors":"Margherita Fittipaldi ,&nbsp;Daniele Trippanera ,&nbsp;Nico Augustin ,&nbsp;Froukje M. van der Zwan ,&nbsp;Laura Parisi ,&nbsp;Sigurjón Jónsson","doi":"10.1016/j.margeo.2025.107645","DOIUrl":"10.1016/j.margeo.2025.107645","url":null,"abstract":"<div><div>The northern Red Sea is largely floored by evaporites, covering its basement structure and associated lithology of the lithosphere. The basement is exposed at only a few locations, called “Deeps”. Mabahiss Deep is the largest deep in the northern Red Sea. It hosts a large submarine volcano, Mabahiss Mons, and lies north of the Zabargad Fracture Zone. We use new high-resolution bathymetric data, ROV images, and basalt sample analysis to map the morphology of the Mabahiss Deep to understand the volcano-tectonic setting of this area and study its geologic evolution, providing insights into a young ocean basin that is potentially representative of other ultra-slow spreading ridges worldwide. Our results show that Mabahiss Deep is a 2360 m deep axial valley bordered by NW-SE Red Sea axis-parallel normal faults. The Mabahiss Mons has a ∼2 km summit caldera containing columnar basalts at its footwall, volcanic cones with pillow lavas, and extensive lava flows indicating Holocene activity. The basaltic submarine caldera is rare in such settings but is consistent with considerable lava flows and high melt supply due to magma focusing and elevated heat flux in the Red Sea, in spite of the slow spreading rates. The rock samples analysis shows MORB-type composition without any interaction of continental crust. Together our results show that Mabahiss Deep is a typical mid-oceanic ridge segment, confirming that oceanic spreading processes are occurring in this part of the northern Red Sea.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"490 ","pages":"Article 107645"},"PeriodicalIF":2.2,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047049","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}

{"title":"Geological, geophysical, and geobiological investigation of the inactive Nawaay`as hydrothermal vent field at West Valley, Juan de Fuca Ridge","authors":"Sarah N. Moriarty ,&nbsp;Monika Neufeld ,&nbsp;Zoe Krauss ,&nbsp;John W. Jamieson","doi":"10.1016/j.margeo.2025.107643","DOIUrl":"10.1016/j.margeo.2025.107643","url":null,"abstract":"<div><div>In 2022, an area of now-inactive hydrothermal venting, named the Nawaay`as field, was discovered on a sediment-covered volcanic mound within the axial valley of the West Valley segment of the Juan de Fuca Ridge, northeast Pacific Ocean. Analysis of multibeam backscatter imagery of the ridge segment indicates that volcanic activity along the ridge has resulted in, at minimum, two distinct eruptive events along the valley floor. Younger lava flows emanated from a volcano located near the southern end of the valley, then flowed north, paving over areas of bathymetric lows, but flowing around and thus preserving areas of relative bathymetric highs, including the volcanic mound that hosts the Nawaay`as field. Geochemical and petrographic analysis of Nawaay`as hydrothermal rock samples indicate that the deposit formed over venting temperatures ranging from ∼100 to 300 °C. Although the valley floor is generally sediment-free, trace metal concentrations within the sulfide-rich rock samples suggest that hydrothermal fluids interacted with buried sediments. Distinct differences in deep-sea sponge communities were observed between basaltic and inactive sulfidic substrates at West Valley, indicating that inactive hydrothermal deposits are unique seafloor habitats. Observations of shimmering water, vent-associated fauna, and recent seismic activity suggest the presence of active hydrothermal venting to both the north and south of Nawaay`as. With recent increased interest in the mineral resource potential of the seafloor, studies of inactive vent sites such as Nawaay`as are critical to ensure informed, risk-mitigating marine policy decisions are made in the future.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"489 ","pages":"Article 107643"},"PeriodicalIF":2.2,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144917387","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}