Annelotte Weert, Kei Ogata, Francesco Vinci, Coen Leo, Giovanni Bertotti, Jerome Amory, Stefano Tavani
Abstract. Aiming to contribute to the energy transition, this study provides an integrated picture of the geothermal system hosted in the West Netherlands Basin and shows how the reconstruction of the basin's geological history can contribute to the correct exploration and exploitation of its geothermal resources. In the West Netherlands Basin, the main geothermal targets are found in the Cretaceous and Jurassic strata that were deposited during the rifting and post-rifting stages and were deformed during the subsequent basin inversion. Despite multiple studies on the tectonic setting, the timing and tectono-stratigraphic architecture of the rift system and its overall control on the development and evolution of geothermal systems are still to be fully deciphered. In this study, a detailed seismo-stratigraphic interpretation of the syn- and post-rift intervals in the West Netherlands Basin will be given within the framework of geothermal exploration. A recently released and reprocessed 3D seismic cube is used, covering a large portion of the onshore section of the basin. We identified two major Jurassic rifting episodes and a Late Cretaceous inversion event. During the Jurassic rifting phases, the compartmentalization of the basin and the creation of accommodation space led to the deposition of the Late Jurassic Nieuwerkerk Formation, which is the main regional geothermal producing target. Within this formation, we individuate growth synclines located in the central portions of the Jurassic half-grabens as sites that show good potential for geothermal exploration.
{"title":"Multiple phase rifting and subsequent inversion in the West Netherlands Basin: implications for geothermal reservoir characterization","authors":"Annelotte Weert, Kei Ogata, Francesco Vinci, Coen Leo, Giovanni Bertotti, Jerome Amory, Stefano Tavani","doi":"10.5194/se-15-121-2024","DOIUrl":"https://doi.org/10.5194/se-15-121-2024","url":null,"abstract":"Abstract. Aiming to contribute to the energy transition, this study provides an integrated picture of the geothermal system hosted in the West Netherlands Basin and shows how the reconstruction of the basin's geological history can contribute to the correct exploration and exploitation of its geothermal resources. In the West Netherlands Basin, the main geothermal targets are found in the Cretaceous and Jurassic strata that were deposited during the rifting and post-rifting stages and were deformed during the subsequent basin inversion. Despite multiple studies on the tectonic setting, the timing and tectono-stratigraphic architecture of the rift system and its overall control on the development and evolution of geothermal systems are still to be fully deciphered. In this study, a detailed seismo-stratigraphic interpretation of the syn- and post-rift intervals in the West Netherlands Basin will be given within the framework of geothermal exploration. A recently released and reprocessed 3D seismic cube is used, covering a large portion of the onshore section of the basin. We identified two major Jurassic rifting episodes and a Late Cretaceous inversion event. During the Jurassic rifting phases, the compartmentalization of the basin and the creation of accommodation space led to the deposition of the Late Jurassic Nieuwerkerk Formation, which is the main regional geothermal producing target. Within this formation, we individuate growth synclines located in the central portions of the Jurassic half-grabens as sites that show good potential for geothermal exploration.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":"36 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139769941","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}
Willemijn Sarah Maria Theresia van Kooten, Hugo Ortner, Ernst Willingshofer, Dimitrios Sokoutis, Alfred Gruber, Thomas Sausgruber
Abstract. Within the Northern Calcareous Alps (NCA) fold-and-thrust belt of the Eastern Alps, multiple pre-shortening deformation phases have contributed to the structural grain that controlled localization of deformation at later stages. In particular, Jurassic rifting and opening of the Alpine Tethys led to the formation of extensional basins at the northern margin of the Apulian plate. Subsequent Cretaceous shortening within the Northern Calcareous Alps produced the enigmatic Achental structure, which forms a sigmoidal transition zone between two E–W-striking major synclines. One of the major complexities of the Achental structure is that all structural elements are oblique to the Cretaceous direction of shortening. Its sigmoidal form was, therefore, proposed to be a result of forced folding at the boundaries of the Jurassic Achental basin. This study analyses the structural evolution of the Achental structure through integrating field observations with crustal-scale physical analogue modelling to elucidate the influence of pre-existing crustal heterogeneities on oblique basin inversion. From brittle–ductile models that include a weak basal décollement, we infer that oblique shortening of pre-existing extensional faults can lead to the localization of deformation at the pre-existing structure and predicts thrust and fold structures that are consistent with field observations. Consequently, the Achental low-angle thrust and sigmoidal fold train was able to localize at the former Jurassic basin margin, with a vergence opposite to the controlling normal fault, creating the characteristic sigmoidal morphology during a single phase of NW-directed shortening.
{"title":"Fold localization at pre-existing normal faults: field observations and analogue modelling of the Achental structure, Northern Calcareous Alps, Austria","authors":"Willemijn Sarah Maria Theresia van Kooten, Hugo Ortner, Ernst Willingshofer, Dimitrios Sokoutis, Alfred Gruber, Thomas Sausgruber","doi":"10.5194/se-15-91-2024","DOIUrl":"https://doi.org/10.5194/se-15-91-2024","url":null,"abstract":"Abstract. Within the Northern Calcareous Alps (NCA) fold-and-thrust belt of the Eastern Alps, multiple pre-shortening deformation phases have contributed to the structural grain that controlled localization of deformation at later stages. In particular, Jurassic rifting and opening of the Alpine Tethys led to the formation of extensional basins at the northern margin of the Apulian plate. Subsequent Cretaceous shortening within the Northern Calcareous Alps produced the enigmatic Achental structure, which forms a sigmoidal transition zone between two E–W-striking major synclines. One of the major complexities of the Achental structure is that all structural elements are oblique to the Cretaceous direction of shortening. Its sigmoidal form was, therefore, proposed to be a result of forced folding at the boundaries of the Jurassic Achental basin. This study analyses the structural evolution of the Achental structure through integrating field observations with crustal-scale physical analogue modelling to elucidate the influence of pre-existing crustal heterogeneities on oblique basin inversion. From brittle–ductile models that include a weak basal décollement, we infer that oblique shortening of pre-existing extensional faults can lead to the localization of deformation at the pre-existing structure and predicts thrust and fold structures that are consistent with field observations. Consequently, the Achental low-angle thrust and sigmoidal fold train was able to localize at the former Jurassic basin margin, with a vergence opposite to the controlling normal fault, creating the characteristic sigmoidal morphology during a single phase of NW-directed shortening.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":"72 3 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139667533","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}
Jérémie Giraud, Guillaume Caumon, Lachlan Grose, Vitaliy Ogarko, Paul Cupillard
Abstract. We propose and evaluate methods for the integration of automatic implicit geological modelling into the geophysical (potential field) inversion process. The objective is to enforce structural geological realism and to consider geological observations in a level set inversion, which inverts for the location of the boundaries between rock units. We propose two approaches. In the first approach, a geological correction term is applied at each iteration of the inversion to reduce geological inconsistencies. This is achieved by integrating an automatic implicit geological modelling scheme within the geophysical inversion process. In the second approach, we use automatic geological modelling to derive a dynamic prior model term at each iteration of the inversion to limit departures from geologically feasible outcomes. We introduce the main theoretical aspects of the inversion algorithm and perform the proof of concept using two synthetic studies. The analysis of the results using indicators measuring geophysical, petrophysical, and structural geological misfits demonstrates that our approach effectively steers the inversion towards geologically consistent models and reduces the risk of geologically unrealistic outcomes. Results suggest that the geological correction may be effectively applied to pre-existing geophysical models to increase their geological realism and that it can also be used to explore geophysically equivalent models.
{"title":"Integration of automatic implicit geological modelling in deterministic geophysical inversion","authors":"Jérémie Giraud, Guillaume Caumon, Lachlan Grose, Vitaliy Ogarko, Paul Cupillard","doi":"10.5194/se-15-63-2024","DOIUrl":"https://doi.org/10.5194/se-15-63-2024","url":null,"abstract":"Abstract. We propose and evaluate methods for the integration of automatic implicit geological modelling into the geophysical (potential field) inversion process. The objective is to enforce structural geological realism and to consider geological observations in a level set inversion, which inverts for the location of the boundaries between rock units. We propose two approaches. In the first approach, a geological correction term is applied at each iteration of the inversion to reduce geological inconsistencies. This is achieved by integrating an automatic implicit geological modelling scheme within the geophysical inversion process. In the second approach, we use automatic geological modelling to derive a dynamic prior model term at each iteration of the inversion to limit departures from geologically feasible outcomes. We introduce the main theoretical aspects of the inversion algorithm and perform the proof of concept using two synthetic studies. The analysis of the results using indicators measuring geophysical, petrophysical, and structural geological misfits demonstrates that our approach effectively steers the inversion towards geologically consistent models and reduces the risk of geologically unrealistic outcomes. Results suggest that the geological correction may be effectively applied to pre-existing geophysical models to increase their geological realism and that it can also be used to explore geophysically equivalent models.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":"50 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139667400","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}
Abstract. The structural styles and magnitudes of Alpine tectonic inversion are reviewed for the Atlantic margin of southwestern (SW) Iberia, a region known for its historical earthquakes, tsunamis and associated geohazards. Reprocessed, high-quality 2D seismic data provide new images of tectonic faults, which were mapped to a depth exceeding 10 km for the first time. A total of 26 of these faults comprise syn-rift structures accommodating vertical uplift and horizontal advection (shortening) during Alpine tectonics. At the regional scale, tectonic reactivation has been marked by (a) the exhumation of parts of the present-day continental shelf, (b) local folding and thrusting of strata at the foot of the continental slope, and (c) oversteepening of syn- and post-rift sequences near reactivated faults (e.g. “passive uplift”). This work proves, for the first time, that geometric coherence dominated the growth and linkage of the 26 offshore faults mapped in SW Iberia; therefore, they are prone to reactivate as a kinematically coherent fault network. They form 100–250 km long structures, the longest of which may generate earthquakes with a momentum magnitude (Mw) of 8.0. Tectonic inversion started in the Late Cretaceous, and its magnitude is greater close to where magmatic intrusions are identified. In contrast to previous models, this work postulates that regions in which Late Mesozoic magmatism was more intense comprise thickened, harder crust and form lateral buttresses to northwest–southeast compression. It shows these structural buttresses to have promoted the development of early stage fold-and-thrust belts – typical of convergent margins – in two distinct sectors.
{"title":"Networks of geometrically coherent faults accommodate Alpine tectonic inversion offshore southwestern Iberia","authors":"Tiago M. Alves","doi":"10.5194/se-15-39-2024","DOIUrl":"https://doi.org/10.5194/se-15-39-2024","url":null,"abstract":"Abstract. The structural styles and magnitudes of Alpine tectonic inversion are reviewed for the Atlantic margin of southwestern (SW) Iberia, a region known for its historical earthquakes, tsunamis and associated geohazards. Reprocessed, high-quality 2D seismic data provide new images of tectonic faults, which were mapped to a depth exceeding 10 km for the first time. A total of 26 of these faults comprise syn-rift structures accommodating vertical uplift and horizontal advection (shortening) during Alpine tectonics. At the regional scale, tectonic reactivation has been marked by (a) the exhumation of parts of the present-day continental shelf, (b) local folding and thrusting of strata at the foot of the continental slope, and (c) oversteepening of syn- and post-rift sequences near reactivated faults (e.g. “passive uplift”). This work proves, for the first time, that geometric coherence dominated the growth and linkage of the 26 offshore faults mapped in SW Iberia; therefore, they are prone to reactivate as a kinematically coherent fault network. They form 100–250 km long structures, the longest of which may generate earthquakes with a momentum magnitude (Mw) of 8.0. Tectonic inversion started in the Late Cretaceous, and its magnitude is greater close to where magmatic intrusions are identified. In contrast to previous models, this work postulates that regions in which Late Mesozoic magmatism was more intense comprise thickened, harder crust and form lateral buttresses to northwest–southeast compression. It shows these structural buttresses to have promoted the development of early stage fold-and-thrust belts – typical of convergent margins – in two distinct sectors.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":"280 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139585922","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}
Pub Date : 2024-01-29DOI: 10.5194/egusphere-2023-2590
Guangjun Cui, Jin Liao, Linghua Kong, Cuiying Zhou, Zhen Liu, Lei Yu, Lihai Zhang
Abstract. Red beds belong to slippery formations, and their rapid identification is of great significance for major scientific and engineering issues such as geological hazard risk assessment and rapid response. Existing research often identifies red beds from a qualitative or semi quantitative perspective, resulting in slow recognition speed and inaccurate recognition results, making it difficult to quickly handle landslide geological disasters. Combined with the correlation between red beds geomorphic characteristics, mineral compositions, and chemical compositions, this study established a rapid quantitative identification criterion based on the basic chemical compositions combination rules in the red beds. By collecting chemical compositions data of rocks containing red beds, a total of 241,405 groups data were collected for qualitative and quantitative comparison between multiple sets of chemical composition combinations. The results indicate that simultaneously meeting the following chemical composition combinations can serve as a quantitative criterion for distinguishing red beds from other rocks: SiO2+Al2O3 ≈ 50.7 %~85.0 %, Al2O3/SiO2 ≈ 0.14~0.41, FeO+Fe2O3 ≈ 0.9 %~7.9 %, Fe2O3/FeO ≈ 1.52~7.70, K2O+Na2O ≈ 1.6 %~6.8 %, Na2O/K2O ≈ 0.02~0.43, CaO+MgO ≈ 0.8 %~9.2 %. By comparing the chemical composition combinations of 15 kinds of rocks collected from China in this study, it is proven that the quantitative criterion proposed in this study are effective.
{"title":"Basic chemical compositions combination rules and quantitative criterion of red beds","authors":"Guangjun Cui, Jin Liao, Linghua Kong, Cuiying Zhou, Zhen Liu, Lei Yu, Lihai Zhang","doi":"10.5194/egusphere-2023-2590","DOIUrl":"https://doi.org/10.5194/egusphere-2023-2590","url":null,"abstract":"<strong>Abstract.</strong> Red beds belong to slippery formations, and their rapid identification is of great significance for major scientific and engineering issues such as geological hazard risk assessment and rapid response. Existing research often identifies red beds from a qualitative or semi quantitative perspective, resulting in slow recognition speed and inaccurate recognition results, making it difficult to quickly handle landslide geological disasters. Combined with the correlation between red beds geomorphic characteristics, mineral compositions, and chemical compositions, this study established a rapid quantitative identification criterion based on the basic chemical compositions combination rules in the red beds. By collecting chemical compositions data of rocks containing red beds, a total of 241,405 groups data were collected for qualitative and quantitative comparison between multiple sets of chemical composition combinations. The results indicate that simultaneously meeting the following chemical composition combinations can serve as a quantitative criterion for distinguishing red beds from other rocks: SiO<sub>2</sub>+Al<sub>2</sub>O<sub>3</sub> ≈ 50.7 %~85.0 %, Al<sub>2</sub>O<sub>3</sub>/SiO<sub>2</sub> ≈ 0.14~0.41, FeO+Fe<sub>2</sub>O<sub>3</sub> ≈ 0.9 %~7.9 %, Fe<sub>2</sub>O<sub>3</sub>/FeO ≈ 1.52~7.70, K<sub>2</sub>O+Na<sub>2</sub>O ≈ 1.6 %~6.8 %, Na<sub>2</sub>O/K<sub>2</sub>O ≈ 0.02~0.43, CaO+MgO ≈ 0.8 %~9.2 %. By comparing the chemical composition combinations of 15 kinds of rocks collected from China in this study, it is proven that the quantitative criterion proposed in this study are effective.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":"10 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139585927","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}
Pub Date : 2024-01-29DOI: 10.5194/egusphere-2023-2091
Chuang Zhang
Abstract. The basin-related hydrothermal mineral deposits are the products of metal deposition in a relatively small area from metal-rich saline brines that source from basins. Recent studies have confirmed that the metal-rich ore-forming fluids were formed in semi-arid to arid environments, and are the products of a complex system involving precipitation, weathering, groundwater, precipitation-dissolution reactions, and evaporation. The evaporation is the main reason for the buildup of metals in saline brines. The formation of metal-rich saline brines is commonly accompanied by the formation of evaporites. The statistical results of basin-related mineral deposits worldwide show that there are two metallogenic periods after the great oxidation event: 2.1–1.4 Ga (Period I) and 0.8 Ga to present (Period II), with few scattered between these two periods (metallogenic quiescence period). In addition, Metallogenic Period II has five metallogenic peaks: ~380–340 Ma (II-1), ~300–240 Ma (II-2), ~160–100 Ma (II-3), 60–40 Ma (II-4), and one specific stratiform Cu metallogenic concentration period of ~580–500 Ma (II-5). These two metallogenic periods and five peaks are coupled with the widespread development of saline deposits in time. The basin-related ore deposits are mainly symmetrically occurring in 10°–60° in paleo-latitudes, which is consistent with the occurring latitudes of evaporites. The metallogenic quiescence period corresponded to the scarcity of saline deposits and was probably caused by the combination of a lack of hydrological closed basins and arid to semi-arid environments during 1.4–0.8 Ga. This quiescence period was coupled with the booming of stromatolites and the extremely thin continents, both of which suggest an Earth with flat continents that were covered by a hot and wet climate, and the widely developed shallow marine environments of the major continents at middle and low altitudes during 1.4–0.8 Ga.
摘要与盆地有关的热液矿床是来自盆地的富含金属的盐水在相对较小区域内沉积的产物。最新研究证实，富含金属的成矿流体形成于半干旱至干旱环境中，是降水、风化、地下水、降水-溶解反应和蒸发等复杂系统的产物。蒸发是盐湖卤水中金属积聚的主要原因。富含金属的盐湖卤水通常伴随着蒸发岩的形成。世界范围内与盆地有关的矿床统计结果表明，大氧化事件之后有两个金属成矿期：2.1-1.4Ga（成矿期 I）和 0.8Ga 至今（成矿期 II），在这两个成矿期之间（成矿静止期）散布着少量矿床。此外，金属生成期 II 有五个金属生成高峰：~380-340 Ma（II-1）、~300-240 Ma（II-2）、~160-100 Ma（II-3）、60-40 Ma（II-4），以及一个 ~580-500 Ma 的特定层状铜金属成矿富集期（II-5）。这两个成矿期和五个峰值与盐渍矿床的广泛发育时间相吻合。与盆地相关的矿床主要对称分布在古纬度 10°-60°，这与蒸发岩的分布纬度一致。在 1.4-0.8 Ga 期间，由于缺乏水文闭合盆地以及干旱至半干旱环境的共同作用，可能出现了与盐类矿床稀少相对应的成矿静止期。这一静止期与叠层石的蓬勃发展和极薄的大陆同时出现，两者都表明在 1.4-0.8 Ga 期间，地球上大陆平坦，气候湿热，主要大陆的中低海拔浅海环境广泛发育。
{"title":"Climate Affects Global Basin-Related Metallogeny","authors":"Chuang Zhang","doi":"10.5194/egusphere-2023-2091","DOIUrl":"https://doi.org/10.5194/egusphere-2023-2091","url":null,"abstract":"<strong>Abstract.</strong> The basin-related hydrothermal mineral deposits are the products of metal deposition in a relatively small area from metal-rich saline brines that source from basins. Recent studies have confirmed that the metal-rich ore-forming fluids were formed in semi-arid to arid environments, and are the products of a complex system involving precipitation, weathering, groundwater, precipitation-dissolution reactions, and evaporation. The evaporation is the main reason for the buildup of metals in saline brines. The formation of metal-rich saline brines is commonly accompanied by the formation of evaporites. The statistical results of basin-related mineral deposits worldwide show that there are two metallogenic periods after the great oxidation event: 2.1–1.4 Ga (Period I) and 0.8 Ga to present (Period II), with few scattered between these two periods (metallogenic quiescence period). In addition, Metallogenic Period II has five metallogenic peaks: ~380–340 Ma (II-1), ~300–240 Ma (II-2), ~160–100 Ma (II-3), 60–40 Ma (II-4), and one specific stratiform Cu metallogenic concentration period of ~580–500 Ma (II-5). These two metallogenic periods and five peaks are coupled with the widespread development of saline deposits in time. The basin-related ore deposits are mainly symmetrically occurring in 10°–60° in paleo-latitudes, which is consistent with the occurring latitudes of evaporites. The metallogenic quiescence period corresponded to the scarcity of saline deposits and was probably caused by the combination of a lack of hydrological closed basins and arid to semi-arid environments during 1.4–0.8 Ga. This quiescence period was coupled with the booming of stromatolites and the extremely thin continents, both of which suggest an Earth with flat continents that were covered by a hot and wet climate, and the widely developed shallow marine environments of the major continents at middle and low altitudes during 1.4–0.8 Ga.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":"170 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139585923","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}
Pub Date : 2024-01-24DOI: 10.5194/egusphere-2023-3123
Renas Koshnaw, Jonas Kley, Fritz Schlunegger
Abstract. Tectonic processes resulting from solid Earth dynamics control uplift and generate sediment accommodation space via subsidence. Unraveling the mechanism of basin subsidence elucidates the link between deep Earth and Surface processes. The NW Zagros fold-thrust belt results from the Cenozoic convergence and subsequent collision between the Arabian and Eurasian plates. The associated Neogene foreland basin includes ~4 km of syntectonic nonmarine clastic sediments, suggesting a strongly subsiding basin inconsistent with the adjacent topographic load. To explain such discrepancy, we assessed basin subsidence with respect to the effect of surface load and dynamic topography. The isopach map of the Fatha Formation during the middle Miocene displays a longitudinal depocenter aligned with the orogenic trend. In contrast, the maps of the Injana Formation and Mukdadiya Formation during the late Miocene illustrate a focused depocenter in the southern region of the basin. The rapid subsidence in the south during the late Miocene was coeval with the Afar plume flow northward beyond the Arabia-Eurasia suture zone in the northwestern segment of the Zagros belt. Based on isopach maps, subsidence curves, and reconstructions of flexural profiles, supported by Bouguer anomaly data and maps of dynamic topography and seismic tomography, we argue for a two-stage basin evolution. The Zagros foreland basin subsided due to the load of the surface and the subducting slab during the early-middle Miocene and was later affected by the Neothethys horizontal slab tear propagation during the late Miocene. This tear propagation was associated with a northward mantle flow above the detached segment in the NW and a focussed slab pull on the attached portion of the slab in the SE.
{"title":"Miocene evolution of the NW Zagros foreland basin reflects SE-ward propagating tear of the Neotethys slab","authors":"Renas Koshnaw, Jonas Kley, Fritz Schlunegger","doi":"10.5194/egusphere-2023-3123","DOIUrl":"https://doi.org/10.5194/egusphere-2023-3123","url":null,"abstract":"<strong>Abstract.</strong> Tectonic processes resulting from solid Earth dynamics control uplift and generate sediment accommodation space via subsidence. Unraveling the mechanism of basin subsidence elucidates the link between deep Earth and Surface processes. The NW Zagros fold-thrust belt results from the Cenozoic convergence and subsequent collision between the Arabian and Eurasian plates. The associated Neogene foreland basin includes ~4 km of syntectonic nonmarine clastic sediments, suggesting a strongly subsiding basin inconsistent with the adjacent topographic load. To explain such discrepancy, we assessed basin subsidence with respect to the effect of surface load and dynamic topography. The isopach map of the Fatha Formation during the middle Miocene displays a longitudinal depocenter aligned with the orogenic trend. In contrast, the maps of the Injana Formation and Mukdadiya Formation during the late Miocene illustrate a focused depocenter in the southern region of the basin. The rapid subsidence in the south during the late Miocene was coeval with the Afar plume flow northward beyond the Arabia-Eurasia suture zone in the northwestern segment of the Zagros belt. Based on isopach maps, subsidence curves, and reconstructions of flexural profiles, supported by Bouguer anomaly data and maps of dynamic topography and seismic tomography, we argue for a two-stage basin evolution. The Zagros foreland basin subsided due to the load of the surface and the subducting slab during the early-middle Miocene and was later affected by the Neothethys horizontal slab tear propagation during the late Miocene. This tear propagation was associated with a northward mantle flow above the detached segment in the NW and a focussed slab pull on the attached portion of the slab in the SE.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":"170 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139585783","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}
Pub Date : 2024-01-19DOI: 10.5194/egusphere-2024-85
Amélie Viger, Stéphane Dominguez, Stéphane Mazzotti, Michel Peyret, Maxime Henriquet, Giovanni Barreca, Carmelo Monaco, Adrien Damon
Abstract. New satellite geodetic data challenge our knowledge of the deformation mechanisms driving the active deformations affecting Southeastern Sicily. The PS-InSAR measurements evidence a generalized subsidence and an eastward tilting of the Hyblean Plateau combined with a local relative uplift along its eastern coast. In order to find a mechanical explanation for the present-day strain field, we investigate short and large-scale surface-to-crustal deformation processes. Geological and geophysical data suggest that the southward migration of the Calabrian subduction could be the causative geodynamic process. We evaluate this hypothesis using flexural modeling and show that the overloading of the Calabrian accretionary prism, combined with the downward pull force induced by the Ionian slab roll-back, are capable of flexuring the adjacent Hyblean continental crust, explaining the measured large-scale subsidence and eastward bending of the Hyblean Plateau. To explain the short-scale relative uplift evidenced along the eastern coast, we perform elastic modeling on identified or inferred onshore and offshore normal faults. We also investigate the potential effects of other deformation processes including upwelling mantle flow, volcanic deflation, and hydrologic loading. Our results enable us to propose an original seismic cycle model for Southeastern Sicily, linking the current interseismic strain field and the available long-term deformation data. This model is mainly driven by the southward migration of the Ionian slab roll-back which induces a downward force capable to flexure the Hyblean crust.
{"title":"Interseismic and long-term deformation of southeastern Sicily driven by the Ionian slab roll-back","authors":"Amélie Viger, Stéphane Dominguez, Stéphane Mazzotti, Michel Peyret, Maxime Henriquet, Giovanni Barreca, Carmelo Monaco, Adrien Damon","doi":"10.5194/egusphere-2024-85","DOIUrl":"https://doi.org/10.5194/egusphere-2024-85","url":null,"abstract":"<strong>Abstract.</strong> New satellite geodetic data challenge our knowledge of the deformation mechanisms driving the active deformations affecting Southeastern Sicily. The PS-InSAR measurements evidence a generalized subsidence and an eastward tilting of the Hyblean Plateau combined with a local relative uplift along its eastern coast. In order to find a mechanical explanation for the present-day strain field, we investigate short and large-scale surface-to-crustal deformation processes. Geological and geophysical data suggest that the southward migration of the Calabrian subduction could be the causative geodynamic process. We evaluate this hypothesis using flexural modeling and show that the overloading of the Calabrian accretionary prism, combined with the downward pull force induced by the Ionian slab roll-back, are capable of flexuring the adjacent Hyblean continental crust, explaining the measured large-scale subsidence and eastward bending of the Hyblean Plateau. To explain the short-scale relative uplift evidenced along the eastern coast, we perform elastic modeling on identified or inferred onshore and offshore normal faults. We also investigate the potential effects of other deformation processes including upwelling mantle flow, volcanic deflation, and hydrologic loading. Our results enable us to propose an original seismic cycle model for Southeastern Sicily, linking the current interseismic strain field and the available long-term deformation data. This model is mainly driven by the southward migration of the Ionian slab roll-back which induces a downward force capable to flexure the Hyblean crust.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":"82 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139501323","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}
Changyeol Lee, Nestor G. Cerpa, Dongwoo Han, Ikuko Wada
Abstract. Fluid and melt transport in the solid mantle can be modeled as a two-phase flow in which the liquid flow is resisted by the compaction of the viscously deforming solid mantle. Given the wide impact of liquid transport on the geodynamical and geochemical evolution of the Earth, the so-called “compaction equations” are increasingly being incorporated into geodynamical modeling studies. When implementing these equations, it is common to use a regularization technique to handle the porosity singularity in the dry mantle. Moreover, it is also common to enforce a positive porosity (liquid fraction) to avoid unphysical negative values of porosity. However, the effects of this “capped” porosity on the liquid flow and mass conservation have not been quantitatively evaluated. Here, we investigate these effects using a series of 1- and 2-dimensional numerical models implemented using the commercial finite-element package COMSOL Multiphysics®. The results of benchmarking experiments against a semi-analytical solution for 1- and 2-D solitary waves illustrate the successful implementation of the compaction equations. We show that the solutions are accurate when the element size is smaller than half of the compaction length. Furthermore, in time-evolving experiments where the solid is stationary (immobile), we show that the mass balance errors are similarly low for both the capped and uncapped (i.e., allowing negative porosity) experiments. When Couette flow, convective flow, or subduction corner flow of the solid mantle is assumed, the capped porosity leads to overestimations of the mass of liquid in the model domain and the mass flux of liquid across the model boundaries, resulting in intrinsic errors in mass conservation even if a high mesh resolution is used. Despite the errors in mass balance, however, the distributions of the positive porosity and peaks (largest positive liquid fractions) in both the uncapped and capped experiments are similar. Hence, the capping of porosity in the compaction equations can be reasonably used to assess the main pathways and first-order distribution of fluids and melts in the mantle.
{"title":"Modeling liquid transport in the Earth's mantle as two-phase flow: effect of an enforced positive porosity on liquid flow and mass conservation","authors":"Changyeol Lee, Nestor G. Cerpa, Dongwoo Han, Ikuko Wada","doi":"10.5194/se-15-23-2024","DOIUrl":"https://doi.org/10.5194/se-15-23-2024","url":null,"abstract":"Abstract. Fluid and melt transport in the solid mantle can be modeled as a two-phase flow in which the liquid flow is resisted by the compaction of the viscously deforming solid mantle. Given the wide impact of liquid transport on the geodynamical and geochemical evolution of the Earth, the so-called “compaction equations” are increasingly being incorporated into geodynamical modeling studies. When implementing these equations, it is common to use a regularization technique to handle the porosity singularity in the dry mantle. Moreover, it is also common to enforce a positive porosity (liquid fraction) to avoid unphysical negative values of porosity. However, the effects of this “capped” porosity on the liquid flow and mass conservation have not been quantitatively evaluated. Here, we investigate these effects using a series of 1- and 2-dimensional numerical models implemented using the commercial finite-element package COMSOL Multiphysics®. The results of benchmarking experiments against a semi-analytical solution for 1- and 2-D solitary waves illustrate the successful implementation of the compaction equations. We show that the solutions are accurate when the element size is smaller than half of the compaction length. Furthermore, in time-evolving experiments where the solid is stationary (immobile), we show that the mass balance errors are similarly low for both the capped and uncapped (i.e., allowing negative porosity) experiments. When Couette flow, convective flow, or subduction corner flow of the solid mantle is assumed, the capped porosity leads to overestimations of the mass of liquid in the model domain and the mass flux of liquid across the model boundaries, resulting in intrinsic errors in mass conservation even if a high mesh resolution is used. Despite the errors in mass balance, however, the distributions of the positive porosity and peaks (largest positive liquid fractions) in both the uncapped and capped experiments are similar. Hence, the capping of porosity in the compaction equations can be reasonably used to assess the main pathways and first-order distribution of fluids and melts in the mantle.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":"11 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139482704","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}
Pub Date : 2024-01-10DOI: 10.5194/egusphere-2023-2894
Jian Wang, Renguang Zuo, Qinghai Liu
Abstract. Geochemical mapping is a fundamental tool for elucidating the distribution and behaviour of economically significant elements, and providing valuable insights for geological processes. Nevertheless, the quantification of uncertainty associated with geochemical mapping has recently become a subject of widespread concern. This study presents a procedure, primarily involving the determination of homogeneous clusters, the recognition of elemental associations for each cluster, and the identification of geochemical anomalies, with the aim to account for the uncertainty of elemental association in geochemical mapping. To illustrate and validate the procedure, a case study was conducted wherein stream sediment geochemical samples from the northwestern Sichuan Province, China were processed to map anomalies associated with disseminated gold mineralization. The results indicate: (1) the representativeness of elemental association for the underlying geological process is an important source of uncertainty for geochemical mapping, (2) the procedure presented here is effective to incorporate the uncertainty of elemental association in geochemical mapping, and (3) the study area can be classified into two clusters, each characterized by unique elemental associations that align well with the distribution of Paleozoic and Triassic lithological units, respectively. Furthermore, the region still holds great potential for the discovery of gold deposits, particularly in areas proximal to known mineralization sites.
{"title":"Mapping geochemical anomalies by accounting for the uncertainty of mineralization-related elemental associations","authors":"Jian Wang, Renguang Zuo, Qinghai Liu","doi":"10.5194/egusphere-2023-2894","DOIUrl":"https://doi.org/10.5194/egusphere-2023-2894","url":null,"abstract":"<strong>Abstract.</strong> Geochemical mapping is a fundamental tool for elucidating the distribution and behaviour of economically significant elements, and providing valuable insights for geological processes. Nevertheless, the quantification of uncertainty associated with geochemical mapping has recently become a subject of widespread concern. This study presents a procedure, primarily involving the determination of homogeneous clusters, the recognition of elemental associations for each cluster, and the identification of geochemical anomalies, with the aim to account for the uncertainty of elemental association in geochemical mapping. To illustrate and validate the procedure, a case study was conducted wherein stream sediment geochemical samples from the northwestern Sichuan Province, China were processed to map anomalies associated with disseminated gold mineralization. The results indicate: (1) the representativeness of elemental association for the underlying geological process is an important source of uncertainty for geochemical mapping, (2) the procedure presented here is effective to incorporate the uncertainty of elemental association in geochemical mapping, and (3) the study area can be classified into two clusters, each characterized by unique elemental associations that align well with the distribution of Paleozoic and Triassic lithological units, respectively. Furthermore, the region still holds great potential for the discovery of gold deposits, particularly in areas proximal to known mineralization sites.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":"28 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139414143","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}
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