Marine Geology最新文献

{"title":"Clinoform architecture influenced by salt tectonics and Quaternary Sea level changes: The Acheloos delta complex, Gulf of Patras, Greece","authors":"Aikaterini Stathopoulou ,&nbsp;George Papatheodorou ,&nbsp;Efthymios Tripsanas ,&nbsp;Aurelia Ferrari ,&nbsp;Romain Rubi ,&nbsp;Maria Geraga ,&nbsp;Sotirios Kokkalas ,&nbsp;Aristofanis Stefatos","doi":"10.1016/j.margeo.2025.107494","DOIUrl":"10.1016/j.margeo.2025.107494","url":null,"abstract":"<div><div>This study focuses on the evolution of the Acheloos river-dominated delta in western Greece. It is an area with limited published data, that serves as a link between the well-studied rift basin of the Gulf of Corinth and the active Kephalonia Transform Fault. The examination of a newly acquired 3D seismic cube and vintage well data in this area offers a rare opportunity to: i) develop a stratigraphic scheme for the evolution of river-dominated deltas in restricted basins influenced by salt tectonics, which can be applied as an analogue to similar deltas worldwide, and ii) re-evaluate the deformation style of the study area and challenge the widely accepted concept of its tectonic behavior as a rigid block.</div><div>Detailed 3D seismic stratigraphy and well data revealed eleven progradational packages. These are attributed to the Acheloos activity during Pleistocene and exhibit distinctive spatial variation. Thickness distribution and trajectory analysis show that the delta developed in three stages: (i) poorly developed progradational units in a weakly subsiding basin, (ii) retrogradational delta units in a strongly subsiding basin and (iii) stabilization of the accommodation space and gradual basin infill through progradational units.</div><div>Although the study area has been considered a rigid block, stratigraphic analysis revealed multiple subsidence events linked to the structural history of the basin. Additionally, seismic data reveal that salt tectonics have a significant impact on its evolution, affecting the locus of the depocenters and the subsidence rates. The deformation of the underlying strata shows that the salt diapiric activity intensified from 435 ka to present. This can either be attributed to the differential loading due to the continuous deltaic sedimentation and/or to the structural activity within the study area. Notably, the paroxysmal phase of salt tectonics occurs right after a large subsidence of the area of interest between 860 and 550 ka.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"482 ","pages":"Article 107494"},"PeriodicalIF":2.6,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419090","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":"Marginal marine spring carbonates defining an emergent rocky shoreline at Cape Freycinet, Western Australia","authors":"Thomas W. Garner ,&nbsp;J. Andrew G. Cooper ,&nbsp;Alan Smith","doi":"10.1016/j.margeo.2025.107496","DOIUrl":"10.1016/j.margeo.2025.107496","url":null,"abstract":"<div><div>Modern and Holocene tufa microbialites have been documented globally on groundwater spring-fed supratidal rock coasts. Here, we document the first emergent facies assemblage and demonstrate its utility as a palaeo-shoreline (and sea-level) indicator. At Cape Freycinet, Western Australia, discrete palaeo-spring-associated deposits comprise five distinct facies that collectively define a Quaternary shoreline on a granitic rock coast similar to the contemporary coast. A palaeosol facies, passes laterally seaward into tufa microbialite on sub-horizontal bedrock, associated with oncoids. The most seaward facies is a microbially-cemented sand representing deposition in the upper-intertidal to supratidal zone of a sandy embayed beach, flanked by prominent headlands. A tufa-lithoclast breccia indicates occasional high-energy events. Facies distributions are controlled by bedrock topography in relation to palaeo-sea-level and the distinct suite of marginal marine, springline-associated facies define a Quaternary palaeo-shoreline at ca. +13 m above sea-level. The approach demonstrates the utility of marginal marine microbialite and related carbonate deposits as indicators of Quaternary sea-level on rock coasts.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"481 ","pages":"Article 107496"},"PeriodicalIF":2.6,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143262129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Initiation and internal structure of temperate coral reef community over the past 7.3 kyr in Kushimoto, mainland of Japan","authors":"Chuki Hongo ,&nbsp;Ryuji Asami ,&nbsp;Hiroya Yamano","doi":"10.1016/j.margeo.2025.107499","DOIUrl":"10.1016/j.margeo.2025.107499","url":null,"abstract":"<div><div>The initiation timing and formation process of coral community in areas where coral reefs have not developed beyond 30°N are still unclear. We conducted underwater drilling of carbonate rocks to the bedrock in Kushimoto area (33.45°N, 135.75°E), Wakayama Prefecture, located on the Pacific side of mainland of Japan, and first discovered that the initiation of coral community formation in this area dates back to 7.3 ka (7487–7210 cal. yr BP, within 2σ range). This onset could be because of the warming resulting from the Kuroshio warm current approaching the Pacific side of mainland of Japan around 10–7 ka. Interestingly, we found that this period aligns closely with the onset of coral reef formation in subtropical regions of the northwestern Pacific. While Acroporidae is the primary builders of coral reefs in tropical to subtropical regions, the coral communities in Kushimoto area were formed predominantly by domal Merulinidae (<em>Cyphastrea</em>, <em>Favites</em>, and <em>Dipsastraea</em>), representing a single facies formed in low wave energy conditions at depths of approximately 10–20 m. The facies formed by domal corals persisted from 7.3 ka to 3.7 ka, whereas the current dominant coral community is composed of <em>Acropora</em>. However, it remains unclear when this <em>Acropora</em> community began and whether there was a hiatus between 3.7 ka (3849–3525 cal. yr BP, within 2σ range) and the present. The study area has lower SSTs compared to tropical and subtropical regions, which reduces the precipitation of calcium carbonate, hindering the upward growth of corals. Additionally, the relatively smooth rocky substrate of the study area suggests that even if coral communities were to form mounds and reach near the sea surface, they would likely be dislodged by high waves due to the open-ocean environment. As a result, although corals have been inhabiting the area since 7.3 ka, the coral reef remains underdeveloped.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"481 ","pages":"Article 107499"},"PeriodicalIF":2.6,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143379160","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":"Carbonate sediment dynamics in oceanic atoll lagoons of Lakshadweep Archipelago","authors":"Shradha Menon,&nbsp;Pankaj Khanna,&nbsp;Saikat Kumar Misra","doi":"10.1016/j.margeo.2025.107498","DOIUrl":"10.1016/j.margeo.2025.107498","url":null,"abstract":"<div><div>Atoll lagoons grow by constant sediment supply and are increasingly being affected by climate change. The impacts are non-uniform; thus, understanding the mechanisms governing the sediment dynamics is crucial to assessing atoll island stability. Satellite geomorphological and sedimentological studies have been conducted on Agatti and Kavaratti atolls in the Lakshadweep Archipelago (Northern Indian Ocean) to discern factors governing sediment dynamics. These lagoons, with maximum depths of 4 m, are grainstone-dominated (79 % - Agatti &amp; 96 % - Kavaratti). Sand-sized fractions (2–0.125 mm) constitute approx. 87 % and 90 % of the Agatti and Kavaratti lagoon, respectively. The major sediment producers include corals (34–57 % - Agatti; 37–58 % Kavaratti) and molluscs (31–34 % - Agatti; 32–39 % - Kavaratti) followed by forams (8–20 % - Agatti; 2–13 % - Kavaratti), algae (2–7 % - Agatti; 2–10 % - Kavaratti) and <em>Halimeda</em> (1–6 % - Agatti; 1–10 % - Kavaratti); within each sample fraction. Coral clasts and molluscs are prevalent near the north, and algae (including <em>Halimeda</em>) is abundant in the south in Agatti. In Kavaratti, molluscs and algae, and <em>Halimeda</em> are prevalent in the north (near the dredging channel) compared to coral clasts. For both atolls, forams are confined to the south and in the lagoon's interior. Generally, for both atolls, coral clasts and algae (including <em>Halimeda</em>) decrease from the reef flat to the island, while molluscs show opposite trends. Reef flats, patch reefs and seagrass patches serve as significant production zones. Anthropogenic factors (dredging) have altered ocean parameters, evidenced by an increase in algae and molluscs and a decrease in coral clasts. The wave-induced currents dictate sediment redistribution, with lighter components such as molluscs and coral clasts transported across the lagoon, while sheltered zones retain particular components such as forams. The small size of the atolls, shallow bathymetry and sand-sized sediments imply potential bucket fill. As climate change progresses, intensified wave-induced currents (linked to stronger monsoons) will result in the retention of coarse-grained sand, with these components dictating future sediment supply. Coupled with rising coral mortality, molluscs would become dominant, affecting sediment production; leading to land loss. The study underscores the importance of local factors such as geomorphic zones and hydrodynamics in discerning island stability in terms of climate change.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"481 ","pages":"Article 107498"},"PeriodicalIF":2.6,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372415","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":"Impact of Storm Pabuk on a Monsoon Coral Beach: Bidong Island, Terengganu (Malaysia)","authors":"Siti Nur Hanani Zainuddin ,&nbsp;Che Din Mohd Safuan ,&nbsp;Junainah Zakaria ,&nbsp;Cherdvong Saengsupavanich ,&nbsp;Muhammad Zahir Ramli ,&nbsp;Azizi Ali ,&nbsp;Zainudin Bachok ,&nbsp;Fatihah Shariful ,&nbsp;Alya Syakirah Tajul Ariffin ,&nbsp;Idham Khalil ,&nbsp;Aidy M. Muslim ,&nbsp;Hasrizal Shaari ,&nbsp;Baharim Mustapa ,&nbsp;Nor Aslinda Awang ,&nbsp;Mohd Fadzil Akhir ,&nbsp;Ikha Magdalena ,&nbsp;Effi Helmy Ariffin","doi":"10.1016/j.margeo.2025.107495","DOIUrl":"10.1016/j.margeo.2025.107495","url":null,"abstract":"<div><div>Monsoon-influenced coasts commonly exhibit a clear seasonal pattern that may be undergoing variability associated with increased storm activity. A notable example is a rare tropical cyclone event in Malaysian waters in January 2019 that affected both marine and terrestrial environments in an exceptional context that diverged from seasonal Monsoon-influenced coastal geomorphic responses to waves. Storm Pabuk made landfall in the South China Sea, with its tail impacting Bidong Island, a coral reef island in Terengganu, Malaysia. Using data on coral coverage cover, aerial imagery obtained from an unmanned aerial vehicle (UAV) and numerical simulations of waves, this study investigates the shoreline changes caused by the cyclone, focusing on coral distribution and wave parameter modeling. The results reveal, unsurprisingly, that the coral reef beach was negatively affected, with a significant reduction in live coral cover. Interestingly, however, the shoreline saw an increase in beach sediment accumulation as well as shoreline length, highlighting both the negative erosion impacts of storms on corals but also their tendency to liberate new beach sediment. The effects of Storm Pabuk illustrate the importance of considering exceptional events in the study of Monsoon-influenced beach dynamics, especially in settings characterized by corals.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"481 ","pages":"Article 107495"},"PeriodicalIF":2.6,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372416","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":"Late Quaternary high-resolution shallow seismic interpretation: Recognition of depositional sequences and systems tracts in response to sea-level changes in the northernmost part of the central Vietnam continental shelf","authors":"Nguyen Van Kieu ,&nbsp;Pham Nguyen Ha Vu ,&nbsp;Pham Hong Trang ,&nbsp;Ha Quang Man","doi":"10.1016/j.margeo.2024.107465","DOIUrl":"10.1016/j.margeo.2024.107465","url":null,"abstract":"<div><div>This study presents the findings from a high-resolution shallow seismic profiles acquired in the northernmost part of the central Vietnam continental shelf. The purpose was to investigate the evolution of the late Quaternary succession. The seismic grid was correlated with two geotechnical boreholes and five gravity cores, providing a comprehensive understanding of the late Quaternary stratigraphy. The seismic stratigraphic interpretation reveals four major seismic facies (F1–F4) and identifies six stratigraphic unconformity surfaces, establishing their relationship with six seismo-stratigraphic sequences and the corresponding depositional system tracts within each sequence. The sequence boundaries have been erosively truncated by a series of incised channels/valleys. These boundaries were unconformably overlain by seismic facies F1 and F2. These facies comprise mostly high amplitude and discontinuous to continuous reflections. They were deposited during a period of relative sea-level fall, resulting in fluvial lowstand deposits of the lowstand systems tract (LST). Below this boundary, toplap terminations of clinoform were observed, corresponding to facies F3. This facies comprise primarily a progradational stacking pattern of the highstand systems tract (HST), transitioning downlap into thinner deposit toward the east-southeast. This suggests the eastward and southeastward transport of sediments from the edge of the Vietnamese mainland, as confirmed by the orientation of the incised channels/valleys. The transgressive systems tract (TST) is thin, and correlates with the seismic characteristics of facies F4, with low amplitude to transparent reflections. This systems tract is commonly bounded above by the highstand systems tract (HST) and below by the lowstand systems tract (LST).</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"480 ","pages":"Article 107465"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143093183","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":"Sedimentary dynamic processes affected by tropical cyclones and anthropogenic forcing in a small-scale estuary: The Sheyang River Estuary, China","authors":"Gang Yang ,&nbsp;Chunhui Li ,&nbsp;Xiang Fan ,&nbsp;Jin Wang ,&nbsp;Xishan Pan ,&nbsp;Xue Han ,&nbsp;Xiangzhen Meng ,&nbsp;Chengyi Zhao ,&nbsp;Changming Dong","doi":"10.1016/j.margeo.2024.107452","DOIUrl":"10.1016/j.margeo.2024.107452","url":null,"abstract":"<div><div>Amid the robust landward migration of tropical cyclones (TCs) in the context of global warming, the sedimentary dynamic processes in coastal areas are increasingly affected by TCs. Concurrently, coastal environments face tremendous stress from anthropogenic interventions, such as land reclamation and jetty construction. However, most research puts more emphasis on TC impacts on large-scale estuaries or marginal seas, leaving the sediment dynamics in small estuaries, particularly under the influence of TCs and man-made structures, largely unexplored due to the limited field data. To address this issue, this study took the Sheyang River Estuary (SRE) as an example and explored the sediment dynamic responses to TCs and the jetty construction during Typhoon Lekima in August 2019, utilizing the Finite Volume Coastal Ocean Model (FVCOM). The results showed that the rotating wind field of Lekima induced rapid variations in wave height, residual water level, and currents at different typhoon stages and strengthened the sediment resuspension and alongshore transport. Furthermore, by comparing the effects of Lekima with Typhoon Chan-hom in July 2015, we found that TCs with different tracks produced markedly different dynamic processes, yet all facilitated sediment exchange between the northern and southern areas within the SRE. The study also highlighted the impact of jetty construction on sediment transport during typhoons, noting that jetties can disrupt the typhoon-induced alongshore sediment flux and create eddies on either side by altering sediment advection. In the navigational channel area, the construction of jetties can strengthen the along-channel estuarine circulation during typhoon events, potentially leading to severe channel siltation by trapping riverine sediments and inducing net landward sediment transport. While site-specific, this study provides valuable insights into the combined effects of extreme events and human interventions on sedimentary environments in small estuaries.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"480 ","pages":"Article 107452"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143097644","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":"Decoding intertidal oyster reef morphology: Insights from UAV photogrammetry and deep learning","authors":"Jiaquan Zhuang ,&nbsp;Qian Yu ,&nbsp;Yidong Guo ,&nbsp;Yun Peng ,&nbsp;Yanan Li ,&nbsp;Yunwei Wang","doi":"10.1016/j.margeo.2024.107462","DOIUrl":"10.1016/j.margeo.2024.107462","url":null,"abstract":"<div><div>Global coverage of oyster reefs has substantially declined due to environmental changes driven by climate change and human activities, severely impairing their ecological functions. Quantitative information on oyster reef morphology is crucial for developing restoration strategies and understanding the ecomorphodynamics of these reefs. This study focused on the Liyashan oyster reef conservation area in the intertidal zone of Haimen, Jiangsu, China. We utilized Unmanned Aerial Vehicle (UAV) photogrammetry to obtain RGB orthoimages and Digital Elevation Models (DEMs) with centimeter-level resolution and accuracy. By integrating UAV photogrammetry and Deep Learning techniques, we efficiently and accurately identified reef footprints and created pixel-level reef height maps. Based on the reef height data, we introduced the Volume Balance Index (VBI) to assess reef fragmentation (degree of pitting), where a lower VBI value indicates higher relative fragmentation. Quantitative results at the reef block scale demonstrate a significant negative correlation between reef size (area and height) and overall fragmentation, with a strong logarithmic relationship between reef height and VBI. Generally, less degraded reefs are primarily distributed in the eastern and southern parts of the region, a pattern potentially related to local hydrodynamic conditions. This study provides a cost-effective and efficient solution for monitoring intertidal oyster reefs and lays the foundation for further research on their ecomorphodynamics.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"480 ","pages":"Article 107462"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143097647","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":"An abrupt change in long-term shoreline behaviour at Roches Beach, Tasmania: An early response to contemporary climate change-induced sea-level rise?","authors":"Chris Sharples,&nbsp;Christopher Watson","doi":"10.1016/j.margeo.2024.107475","DOIUrl":"10.1016/j.margeo.2024.107475","url":null,"abstract":"<div><div>This study analysed a 65-year air photo record for Roches Beach (Australia) which shows that after being mostly stable from at least 1946 until 1985, a major section of the shoreline abruptly switched to a net recession trend which persisted until 2011 when artificial sand replenishment began. Comparable changes have been identified on some other Tasmanian beaches but have only been rarely reported to date. At Roches Beach, consideration of potential causes has identified sea level rise (SLR) as the most plausible driver of the observed change, although increased wave height and vertical land movement (VLM) could also contribute. Climate change induced sea level rise is expected to eventually cause major recession of many shores, however most sandy beaches have not yet shown a clearly attributable response of this sort. We infer that the critical factor causing Roches Beach to undergo an early switch to shoreline recession in response to SLR is its mostly unidirectional littoral drift which transports sand into, through and out of its leaky embayment to a degree not seen in other beaches in the same coastal compartment of Frederick Henry Bay. This delivers a proportion of any eroded sand to the north end of the beach and beyond to a large sand sink at Seven Mile Beach. We deduce that the rising sea-level has increased the frequency and scale of upper beach erosion events, causing increasing net losses of eroded sand from the embayment until the formerly balanced sand budget changed to deficit. Storm records suggest that major erosion events abruptly tipped the beach into a recessional mode when its sand budget was close to deficit. Regional and local confounding processes that may prevent or overwhelm such responses to SLR are minor at this beach. These include swell wave directional variability and interannual sea level variability, both of which are minimal compared to many other Australian coasts. We contend that this allows sea level rise to be more persistently effective at changing the behaviour of Roches Beach than at many other sandy beaches where other causes of variability may be of sufficient magnitude as to mask or prevent persistent changes due to SLR. The factors identified as causing or allowing an early shoreline response to sea level rise will be widely applicable as indicators of other beaches likely to respond early to SLR. This underlines the importance of local studies to identify critical distinctions in susceptibility to SLR between what can be otherwise similar adjacent shores.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"480 ","pages":"Article 107475"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143093182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Widespread contamination of the Pacific upper mantle during the mid-Cretaceous","authors":"K. Durkin ,&nbsp;P.R. Castillo ,&nbsp;S.M. Straub ,&nbsp;S. Mallick ,&nbsp;A. Saal ,&nbsp;J.K. Muller","doi":"10.1016/j.margeo.2024.107460","DOIUrl":"10.1016/j.margeo.2024.107460","url":null,"abstract":"<div><div>This study presents new ¹⁷⁷Hf/¹⁷⁶Hf measurements on variably altered samples from the Early Cretaceous Pacific oceanic crust subducting into the Izu-Bonin trench. The new results are then combined with existing major and trace element and Nd<img>Pb isotopic data to provide further constraints on existing models for the evolution of the Mesozoic Pacific upper mantle. The samples, from an across flow line transect of the oceanic crust accreted along the Pacific-Izanagi ridge system, can be separated into a relatively older (140–127 Ma), mostly normal mid-ocean ridge basalt (N-MORB) group and a younger (&lt;127 Ma) group that includes many enriched (<em>E</em>-)MORBs. The Hf<img>Nd (±Pb) isotope and alteration-resistant incompatible trace element composition of the older N-MORBs is similar to those of the geochemically depleted Jurassic-Early Cretaceous MORBs and Shatsky-Hess Rise platform lavas. On the other hand, the younger <em>E</em>-MORBs are compositionally similar to those of coeval lavas from Ontong Java, Manihiki and Hikurangi plateaus, which were suggested to be previously con-joined as Ontong Java Nui super oceanic plateau, and Ojin Rise Seamounts, which were suggested to be the younger manifestation of the Shatsky-Hess Rise plume. We propose that the older Pacific-Izanagi N-MORBs originated from a depleted MORB mantle (DMM):FOZO (focal zone) mixed source whereas the younger <em>E</em>-MORBs originated from a DMM:FOZO:EMI (enriched mantle 1) ± high μ (HIMU) mixed source. Our results support the proposed widespread contamination of the Pacific upper mantle by geochemically enriched materials that formed the ancestral Ontong Java Nui plateau starting at ca. 125 Ma.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"480 ","pages":"Article 107460"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143093185","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}