Solid Earth最新文献

{"title":"On crustal composition of the Sardinia-Corsica continental block inferred from receiver functions","authors":"Fabio Cammarano, Henrique Berger Roisenberg, Alessio Conclave, Islam Fadel, Mark van der Meijde","doi":"10.5194/egusphere-2024-1515","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1515","url":null,"abstract":"<strong>Abstract.</strong> Subduction-related geodynamic processes significantly influence plate tectonics and Earth’s evolution, yet their impact on the continental crust remains poorly understood. We investigated the Sardinia-Corsica continental block, situated in the Mediterranean Sea, which has experienced intense subduction-driven geodynamic events. By analyzing P-wave receiver functions from our LiSard seismic network and publicly available stations, we aimed to understand crustal structure and composition. We inferred the Moho depth and examined the P-wave to S-wave velocity ratio (<em>V_P</em> /<em>V_S</em> ). We interpret our findings considering petrological data, heat flux measurements, and other geophysical information. We found that the Variscan granitoid batholith has the greatest Moho depths in both Sardinia and Corsica. <em>V_P</em> /<em>V_S</em> ratios (ranging from 1.65 to 1.70) are consistent with average crustal values of <em>SiO</em>₂ between 65 % and 70 %. However, in central Corsica, two stations have exceptionally high <em>V_P</em> /<em>V_S</em> values (&gt;1.80), suggesting the possible presence of serpentinite throughout the crust. In Alpine Corsica, a station exhibited similar high <em>V_P</em> /<em>V_S</em> values but a shallower Moho depth of 21 km. The western part of Sardinia, where Cenozoic volcanism occurred, also showed a shallower Moho depth (20–25 km) and high <em>V_P</em> /<em>V_S</em> values. The highest <em>V_P</em> /<em>V_S</em> value (1.91) is recorded in an area where surface-wave dispersion curves from ambient noise identified the lowest average S-wave velocity and where the highest heat flux has been reported, indicating elevated crustal temperatures and possible presence of melt within the crust. Overall, our results indicate that the recent geodynamic processes have left the granitoid batholith almost intact, with minimal alteration to its composition.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141781967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The role of siliceous sponges in pre-Eocene marine Si cycle from the perspective of rock mineralogy","authors":"Agata Jurkowska, Ewa Świerczewska-Gładysz, Szymon Kowalik Filipowicz","doi":"10.5194/egusphere-2024-2003","DOIUrl":"https://doi.org/10.5194/egusphere-2024-2003","url":null,"abstract":"<strong>Abstract.</strong> The process of siliceous sponge dissolution during diagenesis was interpreted not only as an important part of marine Si cycle (comprising Si burial) but also as a significant mechanism of chert formation (so-called “chertification”; Maliva and Siever, 1989a). Both ideas were widely accepted by researches and are commonly used in geological studies. New research contradicts these seminal assumptions and indicates that in pre-Eocene marine Si cycle, although siliceous sponges were an important part of the ecosystems, did not play a controlling role in regulating dSi (= dissolved silicon) concentration in the porewater as well as in chert formation. The presented studies based on advanced mineralogical (XRD, EBSD; SEM-EDS) and microtextural (SEM) analysis of rocks and sponge remnants verify the role of siliceous sponges in the formation of Cretaceous siliceous rocks, by studying successions deposited in similar marine environments, which contain abundant fossils of siliceous sponges associated with cherts and authigenic silica polymorphs and those without them. For the first time, the mineralogical and microtextural transformations of siliceous sponge loose spicules/rigid skeletal networks, which led to their preservation as siliceous or pyrite/marcasite infillings and also in form of limonite coatings, are presented. The data presented here about the diagenesis of siliceous sponges skeletons opens the discussion on the usefulness of stable isotopic studies of δ³⁰Si in geological studies of fossils of silicifiers preserved as secondary silica polymorphs (opal-CT).","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Naturally fractured reservoir characterisation in heterogeneous sandstones: insight for uranium in situ recovery (Imouraren, Niger)","authors":"Maxime Jamet, Gregory Ballas, Roger Soliva, Olivier Gerbeaud, Thierry Lefebvre, Christine Leredde, Didier Loggia","doi":"10.5194/se-15-895-2024","DOIUrl":"https://doi.org/10.5194/se-15-895-2024","url":null,"abstract":"Abstract. This study delves into the characterisation of a heterogenous reservoir, the Tchirezrine II sandstone unit in northern Niger. The characterisation is crucial for potential uranium in situ recovery (ISR) in a naturally fractured and faulted context. Employing a multifaceted approach, including well log data, optical borehole imagery, and hydrogeological tests, alongside satellite-based lineament analysis, this study provides a comprehensive understanding of the structures and their impact on fluid flow. Lineament analysis reveals scale-dependent patterns, consistent with spatially homogeneous joint networks restricted to mechanical units, as well as nearly scale-invariant patterns, better corresponding to spatially heterogeneous fault networks. Various deformation structures are detected from borehole imagery, including extensional fractures, cataclastic deformation bands, and brecciated–cataclastic fault cores. Based on well log data, the Tchirezrine II reservoir displays heterogeneous porosity and permeability related to its fluvial context. These data differ from the traditional porosity–permeability relationship obtained in a sandstone reservoir matrix but are instead consistent with Nelson's classification, emphasising the impact of deformation structures on such petrophysical properties. Hydrological tests have been implemented into a zone of E–W-trending deformation structures, revealing a strong permeability anisotropy. This strong E–W anisotropy is consistent with the presence of the observed E–W structures, i.e. with a draining behaviour of extensional open fractures and a sealing behaviour of both cataclastic bands and fault rocks. Considering implications for ISR mining, this study allows the discussion of the interplay between fractures, faults, and fluid flow properties. It suggests that a well pattern perpendicular to the main permeability orientation can attenuate channelled flow, thus improving the contact of the leach solution with the mineralised matrix. These results provide an integrated approach and a multi-scale characterisation of naturally fractured reservoir (NFR) properties in sandstone, offering a basis for the optimisation of NFR production such as ISR development.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141781968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extraction of pre-earthquake anomalies from borehole strain data using Graph WaveNet: a case study of the 2013 Lushan earthquake in China","authors":"Chenyang Li, Yu Duan, Ying Han, Zining Yu, Chengquan Chi, Dewang Zhang","doi":"10.5194/se-15-877-2024","DOIUrl":"https://doi.org/10.5194/se-15-877-2024","url":null,"abstract":"Abstract. On 20 April 2013, Lushan experienced an earthquake with a magnitude of 7.0. In seismic assessments, borehole strainmeters, recognized for their remarkable sensitivity and inherent reliability in tracking crustal deformation, are extensively employed. However, traditional data-processing methods encounter challenges when handling massive dataset-s. This study proposes using a Graph WaveNet graph neural network to analyze borehole strain data from multiple stations near the earthquake epicenter and establishes a node graph structure using data from four stations near the Lushan epicenter, covering the years 2010–2013. After excluding the potential effects of pressure, temperature, and rainfall, we statistically analyzed the pre-earthquake anomalies. Focusing on the Guza, Xiaomiao, and Luzhou stations, which are the closest to the epicenter, the fitting results revealed two acceleration events of anomalous accumulation that occurred before the earthquake. Occurring approximately 4 months before the earthquake event, the first acceleration event indicated the pre-release of energy from a weak fault section. Conversely, the acceleration event observed a few days before the earthquake indicated a strong fault section that reached an unstable state with accumulating strain. We tentatively infer that these two anomalous cumulative accelerations may be related to the preparation phase for a large earthquake. This study highlights the considerable potential of graph neural networks in conducting multistation studies of pre-earthquake anomalies.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141745843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantifying mantle mixing through configurational entropy","authors":"Erik van der Wiel, Cedric Thieulot, Douwe J. J. van Hinsbergen","doi":"10.5194/se-15-861-2024","DOIUrl":"https://doi.org/10.5194/se-15-861-2024","url":null,"abstract":"Abstract. Geodynamic models of mantle convection provide a powerful tool to obtain insights into the structure and composition of the Earth's mantle that resulted from a long history of differentiating and mixing. Comparing such models with geophysical and geochemical observations is challenging, as these datasets often sample entirely different temporal and spatial scales. Here, we explore the use of configurational entropy, based on tracer and compositional distribution on a global and local scale. We show means to calculate configurational entropy in a 2D annulus and find that these calculations may be used to quantitatively compare long-term geodynamic models with each other. The entropy may be used to analyse, with a single measure, the mixed state of the mantle as a whole and may also be useful to compare numerical models with local anomalies in the mantle that may be inferred from seismological or geochemical observations.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141738110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Palaeoseismic crisis in the Galera Fault (southern Spain): consequences in Bronze Age settlements?","authors":"I. Martin-Rojas, I. Medina-Cascales, F. García-Tortosa, M. O. Rodríguez-Ariza, Fernando Molina González, Juan Antonio Cámara Serrano, Pedro Alfaro","doi":"10.5194/se-15-837-2024","DOIUrl":"https://doi.org/10.5194/se-15-837-2024","url":null,"abstract":"Abstract. Palaeoseismological studies play a crucial role in the seismic characterization of regions with slow-moving faults. This is the case in the central Betic Cordillera, a highly populated area for which the record of prehistoric earthquakes is very limited, despite being one of the regions with the greatest seismic hazard in Spain. We present here a palaeoseismological characterization of the Galera Fault, one of the active faults accommodating deformation in the central Betic Cordillera. We excavated and analysed several trenches along the fault trace. We quantitatively correlate the results from these trenches, resulting in a surface rupture history involving seven or eight events (accounting for the epistemic uncertainties) during the last ca. 24 000 years, with recurrence intervals ranging from 1520 to 1720 years. Further analysis of this surface rupture history seems to indicate that the Galera Fault is prone to producing earthquake clusters as we recorded five events in ∼400 years (ca. 1536–1126 BCE) and only two events in the ∼3200 years that followed. Using the fault geometry and palaeoseismological data, we also carried out a seismogenic characterization of the fault. This analysis yielded a maximum expected magnitude of 6.7 ± 0.3 and a recurrence interval of 1857 years. Furthermore, we also present a geodetic rupture scenario for the maximum expected event, involving displacements of up to 0.5 m. Finally, we discuss the possible impact of the deduced palaeoearthquakes on the development of Bronze Age human settlements located in the vicinity of the fault. In addition to their intrinsic value, our results will provide the basis for future seismic-hazard assessments carried out in the central Betic Cordillera.\u0000","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141641603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Highlights on mantle deformation beneath the Western Alps with seismic anisotropy using CIFALPS2 data","authors":"S. Pondrelli, S. Salimbeni, J. Confal, M. Malusà, Anne Paul, Stephane Guillot, S. Solarino, E. Eva, C. Aubert, Liang Zhao","doi":"10.5194/se-15-827-2024","DOIUrl":"https://doi.org/10.5194/se-15-827-2024","url":null,"abstract":"Abstract. There are still open questions about the deep structure beneath the Western Alps. Seismic velocity tomographies show the European slab subducting beneath the Adria plate, but all these images did not clarify completely the possible presence of tears, slab windows, or detachments. Seismic anisotropy, considered an indicator of mantle deformation and studied using data recorded by dense networks, allows a better understanding of mantle flows in terms of location and orientation at depth. Using the large amount of shear wave-splitting and splitting-intensity measurements available in the Western Alps, collected through the CIFALPS2 temporary seismic network, together with already available data, some new patterns can be highlighted, and gaps left by previous studies can be filled. Instead of the typical seismic anisotropy pattern parallel to the entire arc of the Western Alps, this study supports the presence of a differential contribution along the belt that is only partly related to the European slab steepening. A nearly north–south anisotropy pattern beneath the external Western Alps, a direction that cuts the morphological features of the belt, is clearly found with the new CIFALPS2 measurements. It is, however, confirmed that the asthenospheric flow from central France towards the Tyrrhenian Sea is turning around the southern tip of the European slab.\u0000","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141645350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights into the tectonic evolution of the Svecofennian orogeny based on in situ Lu-Hf dating of garnet from Olkiluoto, SW Finland","authors":"Jon Engström, Kathryn Cutts, Stijn Glorie, Esa Heilimo, Ester M. Jolis, Radoslaw M. Michallik","doi":"10.5194/egusphere-2024-2034","DOIUrl":"https://doi.org/10.5194/egusphere-2024-2034","url":null,"abstract":"<strong>Abstract.</strong> The Southern Finland granites and associated migmatitic rocks have a complex metamorphic history, being affected by multiple events during the ca. 1.88–1.79 Ga Svecofennian orogeny. In this study, the prolonged tectonic evolution of migmatites and associated rocks in SW Finland has been studied using the new <em>in situ</em> Lu-Hf method. Results reveal detailed temporal constraints for the tectonic evolution that can be linked to major events in adjacent tectonic blocks in both Finland and Sweden during the Svecofennian orogeny. The metamorphic peak at the Olkiluoto site occurred at 1834 ± 7 Ma based on <em>in situ</em> Lu-Hf dating of garnet. The P-T path for the rocks indicates a prograde evolution, with peak P-T conditions of 3–5 kbar and approximately 700 °C. The metamorphic constraints and age presented in this paper enhance our understanding of the geological and tectonic evolution in SW Finland, coupling the Olkiluoto site to the Häme metamorphic and tectonic belt in Finland and highlighting tectonic and metamorphic similarities with the Ljusdal Block of Sweden.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141720157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regional Terrestrial Water Storage Changes in the Yangtze River Delta over the Recent 20 years","authors":"Fengwei Wang, Jianhua Geng, Yunzhong Shen, Yanlin Wen, Tengfei Feng","doi":"10.5194/egusphere-2024-1406","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1406","url":null,"abstract":"<strong>Abstract.</strong> Monitoring changes in regional terrestrial water storage (TWS) and groundwater storage (GWS) is important for effectively managing water resources. Here, we investigate the TWS and GWS changes in the Yangtze River Delta using the GRACE/GRACE-FO mascon solutions, GLDAS NOAH models and in situ groundwater level changes from monitoring wells over the period of April 2002 to December 2022. The results show that the regional mean TWS change rate of the entire Yangtze River Delta is 0.62±0.10 mm/year, at 0.47±0.07 mm/year for the GWS component and 0.15±0.08 mm/year for the other components, which includes soil moisture, snow water and surface water change derived from the GLDAS NOAH models. At the basin scale, significant positive trends existed in water storage in Shanghai and Zhejiang Provinces; however, relatively small negative trends existed in Jiangsu and Anhui Provinces, which was confirmed by the spatial distributions of areas with linear trends. After comparing the estimated GWS change with the in situ groundwater level change from thirteen monitoring wells, we concluded that the groundwater levels in Shanghai and Zhejiang Provinces slightly recovered over the last 20 years and that this trend will continue in the coming years, mainly due to the sustainable water resource management policies of the local governments.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141586415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rift and plume: a discussion on active and passive rifting mechanisms in the Afro-Arabian rift based on synthesis of geophysical data","authors":"Ran Issachar, Peter Haas, Nico Augustin, Jörg Ebbing","doi":"10.5194/se-15-807-2024","DOIUrl":"https://doi.org/10.5194/se-15-807-2024","url":null,"abstract":"Abstract. The causal relationship between the activity of mantle plumes and continental break-up is still elusive. The Afro-Arabian rift system offers an opportunity to examine these relationships, in which an ongoing continental break-up intersects a large Cenozoic plume-related flood basalt series. In the Afar region, the Gulf of Aden, the Red Sea, and the Main Ethiopian Rift form an R-R-R triple junction within plume-related flood basalt series. We provide an up-to-date synthesis of the available geophysical and geological data from this region. We map the rift architecture in the intersection region by applying the difference in Gaussians to the topography and the bathymetry and interpreting vertical gravity gradients and Bouguer anomalies. With the aid of these methods we review the spatiotemporal constraints in the evolution of the different features of the plume–rift system. Our results show rough and irregular morphologies of the Gulf of Aden and the Red Sea arms in contrast to the symmetric, continuous, and smooth Main Ethiopian Rift. The triple junction formed by the northeastward propagation of the Main Ethiopian Rift and developed simultaneously with the abandonment of the tectonic connection between the Red Sea and the Gulf of Aden through Bab al Mandab Strait. The triple junction was the last feature to develop in the plume–rift system and marked a tectonic reorganization. By this time, all rift arms were sufficiently evolved and the break-up between Africa and Arabia was already accomplished. We argue that the classical active and passive rifting mechanisms cannot simply explain the progressive development of the Afro-Arabian rift. Instead, we propose a plume-induced plate rotation, which includes an interaction between active and passive mechanisms. In this tectonic scenario, the arrival of the Afar plume provided a push force that promoted the rotation of Arabia around a nearby pole located to the northwest of the plate boundary, enabling the rifting and, ultimately, the break-up of Arabia from Africa.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141568391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}