Earth and Planetary Science Letters最新文献

{"title":"Magmatic degassing dynamics at Halema'uma'u Crater, Kīlauea, Hawaii","authors":"A. La Spina ,&nbsp;M. Burton ,&nbsp;B.F. Houghton ,&nbsp;A.J. Sutton ,&nbsp;B. Esse","doi":"10.1016/j.epsl.2024.119062","DOIUrl":"10.1016/j.epsl.2024.119062","url":null,"abstract":"<div><div>Lava lake activity within Halema‘uma‘u crater on Kīlauea volcano, Hawaii, between 2010 and 2018 provided a remarkable opportunity to observe the dynamics of magmatic degassing occurring in both quiescent and lava-spattering degassing regimes. We collected open-path FTIR absorption spectra of magmatic gas in December 2015, when distributed lake surface degassing and spattering activity occurred on the SE margin of the lava lake. We quantified seven volcanic gas species, H₂O, CO₂, SO₂, HCl, HF, CO and OCS, distinguishing between spattering and lake surface degassing. Passive and solar traverse measurements allowed quantification of compositions and relative SO₂ emission rates of 60 % from spattering and 40 % from lake surface degassing. Spattering gas has a CO₂/SO₂ molar ratio of 0.88 compared with 0.56 for lake surface degassing, consistent with a partial sulphur loss from magma during spattering. We propose that spattering is the result of continuous formation of coalescing gas bubbles driven by downwelling lava lake crust, which promotes gas loss from 10s-100 s of metres within the lake. Spattering degassing provide a mechanism for partial degassing of magma within the Halema‘uma ‘u lava lake, and production over time of a large volume of partially degassed magma. This is in agreement with petrological models indicating that summit-derived partially degassed magma accumulated in the MERZ in the decade prior to the 2018 LERZ eruption. Calculations of equilibrium temperature and redox state are consistent with gas-rock buffering.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"648 ","pages":"Article 119062"},"PeriodicalIF":4.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Earth's precession rate evolution and rapid fall during the Late Proterozoic","authors":"David Waltham ,&nbsp;Mattias Green","doi":"10.1016/j.epsl.2024.119086","DOIUrl":"10.1016/j.epsl.2024.119086","url":null,"abstract":"<div><div>We consider the use of cyclostratigraphic estimates of ancient Earth-axis precession rates, <em>k</em>, as a proxy for ancient length of day and ancient Earth-Moon distance. Analysis of published estimates for <em>k</em> indicate a statistically robust acceleration in the rate at which <em>k</em> fell during the Late Proterozoic. We investigate whether this accelerated fall-rate can be reasonably explained by an increase in tidal drag, at that time, or whether alternate explanations are needed. A tidal drag explanation requires an unusually large and long-lived resonance in Earth's oceans. However, alternate explanations are even less viable. A rearrangement of Earth's internal structure can be ruled out by the excessive geothermal heat production this would have caused, whilst mass redistribution due to Late Proterozoic glaciation can also be ruled out as the <em>k</em>-history did not return to its former trend after glaciation ended. Disruption of the Earth-Moon-Sun system by a nearby passing star is similarly unable to account for the observations since the required disruption is much too large to have happened without additional, clearly observable effects. We also consider a possible impact from thermally driven, atmospheric tides but reject this explanation as it would decelerate the fall in precession rather than accelerate it. These conclusions required development of novel techniques for inverse modelling the <em>k</em>-history to directly give (i) tidal-drag and (ii) the potential energy liberated by internal mass distribution.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"648 ","pages":"Article 119086"},"PeriodicalIF":4.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemical constraints on reaction temperature and pressure and heat- and mass-transfer efficiency at Rainbow Hydrothermal Field","authors":"Guy N. Evans ,&nbsp;Adedapo N. Awolayo ,&nbsp;Benjamin M. Tutolo ,&nbsp;William E. Seyfried Jr.","doi":"10.1016/j.epsl.2024.119063","DOIUrl":"10.1016/j.epsl.2024.119063","url":null,"abstract":"<div><div>Seafloor vent fluids hosted by oceanic core complexes (OCCs) are thought to represent circulation of seawater-derived hydrothermal fluid along deeply penetrating, low-angle detachment faults. However, estimation of the source temperatures and pressures of such fluids has been limited because geochemical methods typically require vent fluid silica concentrations to be buffered by quartz, a condition not often met at oceanic core complexes. Here, we extend the calculation of the Si-Cl geothermobarometer to enable predictions of fluid Si concentrations in equilibrium with any Si-buffering mineral assemblage, rather than being restricted to quartz. We apply this method to Rainbow Hydrothermal Field vent fluid compositions and find that they are consistent with buffering by a plagioclase+talc+chlorite+tremolite mineral assemblage at conditions ranging from (430 °C, 359 bar) to (470 °C, 468 bar), which correspond to depths of 1.3–2.4 km below the seafloor. These estimates agree well with the locations of seismically imaged magma chambers within the Rainbow Massif. Additionally, calculations of fluxibility and Fe solubility support this relatively shallow origin for Rainbow vent fluids and imply relatively efficient heat and Fe extraction from the seafloor. We estimate that only 24–30 % of the heat content and almost no Fe is lost during upflow of Rainbow vent fluids.</div><div>Compared to other OCC-hosted seafloor vents, the source region of Rainbow vent fluids is anomalously shallow, an observation consistent with geological interpretations of the Rainbow Massif. Vent fluids at Rainbow Hydrothermal Field have exhibited apparently stable and greater-than-seawater salinity for over two decades. We interpret these vent fluids as vapors derived from a higher-salinity source fluid that developed over multiple cycles of magma injection and phase-separation inherent to the formation of oceanic crust along slow-spreading, non-volcanic segments of oceanic spreading centers. Alternatively, higher-salinity source fluids could be derived from mineral hydration reactions associated with serpentinization of ultramafic rocks. The occurrence of greater-than-seawater salinity vent fluids is thus predicted to be a common feature of OCC-hosted vent fields, as indicated by several known examples, including the TAG, Kairei, and Edmond vent fields.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"648 ","pages":"Article 119063"},"PeriodicalIF":4.8,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Complicated thermo-chemical heterogeneity of the mantle transition zone beneath the Philippine Sea Plate revealed by SS precursors investigation","authors":"Fan Yang ,&nbsp;Juan Li ,&nbsp;Chunquan Yu ,&nbsp;Sidan Chen ,&nbsp;Yang Li ,&nbsp;Zhigang Zhang ,&nbsp;Wei Wang","doi":"10.1016/j.epsl.2024.119092","DOIUrl":"10.1016/j.epsl.2024.119092","url":null,"abstract":"<div><div>The Philippine Sea Plate (PSP), a region renowned for its intricate history of multi-stage subduction and back-arc extension, encounters difficulties in elucidating its deep seismic structure, primarily due to the sparse distribution of seismic stations. This study uses over 44,086 traces of SS precursors collected from &gt;1,000 seismic stations over 10–20 years period, to image the mantle transition zone (MTZ) beneath the PSP. With the curvelet denoising technique, we provide high-resolution maps of the depths of the 410 km (D410) and 660 km (D660) discontinuities and the thickness of the MTZ. Notably, we demonstrate a 10–35 km MTZ thickening extending from the West Philippine Basin to the Shikoku Basin, which may be associated with the thermal effect and dehydration of stagnated slabs in the MTZ. Furthermore, the reflection gap and multiple reflectors were both observed in D410 and D660 beneath the Mariana Trench, which suggests that the vertically subducted Pacific plate transports substantial water and non-olivine components into the MTZ in this area. Additionally, a ∼10–25 km MTZ thinning with an abnormally shallow D660 has been observed beneath the Parece Vela Basin and Caroline Plate in the southern PSP, suggesting the potential existence of thermal upwelling from a secondary plume, which may be possibly the tree branch of the Caroline mantle plume in MTZ. Our results provide new seismological constraints on present and past mantle dynamics in and around the PSP.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"648 ","pages":"Article 119092"},"PeriodicalIF":4.8,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantifying the loss of continental crust into the mantle from volume/mass balance calculations in modern collisional mountains","authors":"Ziyi Zhu ,&nbsp;Zefeng Li ,&nbsp;Ian H. Campbell ,&nbsp;Peter A. Cawood ,&nbsp;Neng Lu ,&nbsp;Oliver Nebel","doi":"10.1016/j.epsl.2024.119070","DOIUrl":"10.1016/j.epsl.2024.119070","url":null,"abstract":"<div><div>Reworking and recycling of continental crust, through processes such as erosion and delamination, are essential geological mechanisms that not only shape the topography of continents but also influence the composition of the continental crust and mantle. Continent-continent collisions are crucial settings to study these processes, as they primarily involve the thickening and uplift of the existing crust, with little new crustal addition compared with ocean-continent convergent plate boundaries. In this study, we investigate the three modern collisional systems that formed the Himalaya-Tibetan Plateau, the European Alps, and Zagros in central Asia, and quantify the amount of crust lost into the mantle by comparing the shortened crustal volume with the present-day preserved thickened crust, laterally extruded crust and surficial eroded crust. We find that crustal loss into the mantle accounts for at least 30% of the shortened crust, which exceeds the crust lost by surficial erosion by at least a factor of 2 in the Himalaya-Tibetan Plateau and Zagros. The volume of crust lost into the mantle during the formation of the Alps lies between 15% and 50%, depending on the values assumed for the pre-collisional crustal thickness and the volume of eroded crust.</div><div>For the Himalaya-Tibetan Plateau, our calculated crustal loss corresponds to an elevation increase of ∼ 2 km, which can be explained by delamination of thick, eclogitised lower crustal roots in the late Oligocene, consistent with the distribution of shoshonitic-adakitic magmatism in southern Lhasa. This phase of rapid uplift, which followed the removal of dense lower lithosphere, corresponds with monsoon intensification in southern Asia. Furthermore, extending the concept of crustal loss to ancient mountain belts that occurred during the past cycles of supermountain formation, we propose that detachment of lower crustal roots can explain the trace element and isotopic characteristics of exotic crustal components in some plume-related mantle melts, ultimately linking mountain-building and mantle heterogeneity on a multi-million-year timescale.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"648 ","pages":"Article 119070"},"PeriodicalIF":4.8,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The origin of tectonic mélanges from the Kodiak complex and Shimanto Belt and its implication for subduction interface processes","authors":"Kristijan Rajič ,&nbsp;Hugues Raimbourg ,&nbsp;Vincent Famin ,&nbsp;Benjamin Moris-Muttoni","doi":"10.1016/j.epsl.2024.119085","DOIUrl":"10.1016/j.epsl.2024.119085","url":null,"abstract":"<div><div>Mélanges, intriguing rock units often found in accretionary complexes, consist of basalt lenses embedded in a highly sheared sedimentary matrix. The origin of mélanges remains a subject of vigorous debate, with consequences on our understanding of subduction processes. A first line of thought interprets mélanges as mixed lithologies intertwined by convergent tectonics. Supporters of this interpretation regard mélanges as fossilized witnesses of the lower- and upper-plate interface, with their rheological properties reflecting seismogenic subduction zones. However, a second line of thought is to consider that basalts and sediments were mixed prior to subduction by sedimentary and/or magmatic processes, this mix being only later incorporated into the accretionary wedge.</div><div>In this study, we present evidence supporting the pre-subduction mixing interpretation for mélanges from two paleo-accretionary complexes: the Kodiak complex in Alaska and the Shimanto Belt in Japan. In modern seafloor sediments in contact with basaltic submarine magmas, we show that the crystallinity of carbonaceous particles in sediments increases toward basalts, indicating a ∼1 cm-thick aureole of contact metamorphism. Intriguingly, a comparable aureole of increased crystallinity is observed in four mélanges from the two paleo-accretionary complexes. Basalts were thus emplaced onto and into sediments by magmatism rather than by tectonics, challenging the notion of mélanges explored in this study as formed along the plate boundary interface. Moreover, the studied mélanges are made of mid-ocean ridge basalts, and deposition ages of mélange sediments coincide with proposed ridge subductions. This implies that the mid-ocean ridges at the trench were the source of the magmas that intruded into and extruded onto the clastic sediments and contributed to form the multilayered basalt-sediments architecture.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"648 ","pages":"Article 119085"},"PeriodicalIF":4.8,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decoupled deformation between crust and mantle beneath Indo-Burmese Wedge: A new seismotectonic model","authors":"Debasis D. Mohanty ,&nbsp;Satyapriya Biswal ,&nbsp;Kazunori Yoshizawa","doi":"10.1016/j.epsl.2024.119089","DOIUrl":"10.1016/j.epsl.2024.119089","url":null,"abstract":"<div><div>Ongoing oblique convergence at the eastern margin of the Indo-Eurasian collision zone provides a natural laboratory for studying the deformation and dynamics of subduction beneath the Indo-Burmese Wedge (IBW). Here, we conduct the first comprehensive seismological investigations to understand the mechanical coupling between the crust and mantle beneath IBW using shear-wave splitting analysis and stress modeling. The deformation patterns in the crust signify a strong E-W compressional stress regime throughout IBW, with negligible influence from the major geological structures. These observations derived from local seismicity strongly support that the eastward active subduction of the Indian plate beneath the Burmese sliver is responsible for the crustal-scale deformation. Contrary to the crust, our splitting measurements from the mantle are in line with the major N-S trending arcs created by slip-partitioning due to transpressional oblique subduction. The splitting measurements with an N-S orientated fast axes and the estimated depth of the anisotropy source obtained from the spatial coherency of splitting parameters strongly suggest the presence of trench-parallel sub-slab flow system driven by slab retreat with westward trench migration, which can be the major controlling mechanism of the mantle deformation beneath IBW. Throughout the IBW, a significant change in the orientations of stress and splitting parameters between the crust and mantle supports a decoupled deformation scenario, implying the necessity of a new seismotectonic model. Our integrative study on the present stress patterns and decoupled deformation mechanism between crust and mantle combined with anisotropy measurements beneath the IBW suggests active subduction in the present scenario.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"648 ","pages":"Article 119089"},"PeriodicalIF":4.8,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The persisting conundrum of mantle viscosity inferred from mantle convection and glacial isostatic adjustment processes","authors":"Shunjie Han ,&nbsp;Tao Yuan ,&nbsp;Wei Mao ,&nbsp;Shijie Zhong","doi":"10.1016/j.epsl.2024.119069","DOIUrl":"10.1016/j.epsl.2024.119069","url":null,"abstract":"<div><div>Mantle viscosity exerts important controls on the long-term (i.e., &gt;10⁶ years) dynamics of the mantle and lithosphere and the short-term (i.e., 10 to 10⁴ years) crustal motion induced by loading forces including ice melting, sea-level changes, and earthquakes. However, mantle viscosity structures inferred from modeling observations associated with mantle dynamic and loading processes may differ significantly and remain a hotly debated topic over recent decades. In this study, we investigate the effects of mantle viscosity structures on observations of the geoid, mantle structures, and present-day crustal motions and time-varying gravity by considering five representative mantle viscosity structures in models of mantle convection and glacial isostatic adjustment (GIA). These five viscosity models fall into two categories: 1) two viscosity models derived from modeling the geoid in mantle convection models with ∼100 times more viscous lower mantle than the upper mantle, and 2) the other three with less viscosity increase from the upper to lower mantles that are derived from modeling the late Pleistocene and Holocene relative sea level changes and other observations in GIA models. Our convection models use the plate motion history for the last 130 Myrs as the surface boundary conditions and depth- and temperature-dependent viscosity to predict the present-day convective mantle structure of subducted slabs and the intermediate wavelength (degrees 4–12) geoid. Our GIA models using different ice history models (e.g., ICE-6 G and ANU) compute the GIA-induced present-day crustal motions and time-varying gravity. Our calculations demonstrate that while the viscosity models with a higher viscosity in the lower mantle (∼2 × 10²² Pa^.s) reproduce the degrees 4–12 geoid and seismic slab structures, they significantly over-predict the geodetic (i.e., GPS and GRACE) observations of crustal motions and time varying gravity. Our calculations also show that while two viscosity models derived from fitting the RSL data with averaged mantle viscosity of ∼10²¹ Pa^.s for the top 1200 km of the mantle reproduce well the geodetic observations independent of ice models, they fail to explain the geoid and seismic slab structures. Therefore, our study highlights the persisting conundrum of mantle viscosity structures derived from different observations. We also discuss a number of possible ways including transient, stress-dependent and 3-D viscosity to resolve this important issue in Geodynamics.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"648 ","pages":"Article 119069"},"PeriodicalIF":4.8,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Early and elongated epochs of planetesimal dynamo generation","authors":"Hannah R. Sanderson,&nbsp;James F.J. Bryson,&nbsp;Claire I.O. Nichols","doi":"10.1016/j.epsl.2024.119083","DOIUrl":"10.1016/j.epsl.2024.119083","url":null,"abstract":"<div><div>Accreting in the first few million years (Ma) of the Solar System, planetesimals record conditions in the protoplanetary disc and are the remnants of planetary formation processes. The meteorite paleomagnetic record carries key insights into the thermal history of planetesimals and their extent of differentiation. The current paradigm splits the meteorite paleomagnetic record into three magnetic field generation epochs: an early nebula field (≲5<!--> <!-->Ma after CAI formation), followed by thermal dynamos (∼5–34<!--> <!-->Ma after CAI formation), then a gap in dynamo generation, before the onset of core solidification and compositional dynamos. These epochs have been defined using current thermal evolution and dynamo generation models of planetesimals. Here, we demonstrate these epochs are not as distinct as previously thought based on refined thermal evolution models that include more realistic parametrisations for mantle convection, non-eutectic core solidification, and radiogenic ⁶⁰Fe in the core. We find thermal dynamos can start earlier and last longer. Inclusion of appreciable ⁶⁰Fe in the core brings forward the onset of dynamo generation to ∼1–2<!--> <!-->Ma after CAI formation, which overlaps with the existence of the nebula field. The second epoch of dynamo generation begins prior to the onset of core solidification this epoch is not purely compositionally driven. Planetesimal radius is the dominant control on the strength and duration of dynamo generation, and the choice of reference viscosity can widen the gap between epochs of dynamo generation from 0–200<!--> <!-->Ma. Overall, variations in planetesimal properties lead to more variable timings of different planetesimal magnetic field generation mechanisms than previously thought. This alters the information we can glean from the meteorite paleomagnetic record about the early Solar System. Evidence for the nebula field requires more careful interpretation, and late paleomagnetic remanences, for example in the pallasites, may not be evidence for planetesimal core solidification.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"648 ","pages":"Article 119083"},"PeriodicalIF":4.8,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Controls on fluid discharge at cold seep-hydrate systems: 4D seismic monitoring of Woolsey Mound, Gulf of Mexico","authors":"Ferdinando Cilenti ,&nbsp;Davide Oppo ,&nbsp;Leonardo Macelloni","doi":"10.1016/j.epsl.2024.119087","DOIUrl":"10.1016/j.epsl.2024.119087","url":null,"abstract":"<div><div>Significant increases in methane discharge from gas hydrate systems into the global ocean can influence oceanic carbon dynamics and potentially present significant challenges to ocean biogeochemistry, marine ecosystems, and broader climate. Gas hydrate/cold seep systems are highly dynamic and susceptible to environmental perturbations and processes active in the subsurface. This complexity poses significant challenges in identifying their driving forces and evolution. Through quantitative time-lapse seismic monitoring, we characterized the subsurface fluid dynamics at Woolsey Mound, a gas hydrate/cold seep system in the Gulf of Mexico. Using information from five reflection seismic surveys, we quantified the fluid volumes within the subsurface and reconstructed their migration process from key permeable sedimentary units at different depths up to the seafloor over a time span of 23 years (1991–2014). Our results reveal that fluid discharge is governed by overpressure build-up and subsequent release, enabled by a network of faults and fractures providing connectivity between deep sedimentary units and the seafloor, crossing through the gas hydrate stability zone. Despite gas hydrates reducing the permeability of these faults, overpressure within shallow sedimentary units can induce transient fault permeability and effective fluid migration, thus enhancing fluid discharge at the seafloor. Our analysis identifies the critical role of shallow permeable layers acting as buffers between deep fluid reservoirs and surface discharge points. This buffering mechanism significantly modulates the frequency and intensity of fluid discharge episodes over decadal timescales. Similar processes observed at Woolsey Mound have been hypothesized at cold seep/hydrate systems along active continental margins, suggesting a common model for deep-sourced fluid discharge across environments in different geological and geodynamic contexts. This research advances our understanding of the mechanisms controlling fluid discharge in cold seep/hydrate systems, providing insights into the complex interplay of geological and environmental factors that drive these profoundly dynamic systems.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"648 ","pages":"Article 119087"},"PeriodicalIF":4.8,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534639","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}