Pub Date : 2024-09-12DOI: 10.1186/s00015-024-00463-6
Géraldine N. Zimmerli, Stephan Wohlwend, Gaudenz Deplazes, Jens Becker, Andreas Wetzel, Fabio Francescangeli, Anneleen Foubert
The Opalinus Clay, a silty to sandy claystone formation, Early to Middle Jurassic (Toarcian and Aalenian) in age, has been selected as the host rock for deep subsurface disposal of radioactive waste in Switzerland. Over the past thirty years, numerous geotechnical, mineralogical, and sedimentological studies have been conducted on the Opalinus Clay within the framework of the Nagra (National Cooperative for the Disposal of Radioactive Waste) deep drilling campaigns and the Mont Terri Project, an international research program dedicated to the study of claystone. The present study aims to unravel the variability of the lateral and vertical facies of the Opalinus Clay in central Northern Switzerland and to place this variability in a regional and basinal context. Analyses of new cores drilled in central Northern Switzerland, including petrographic, mineralogical (X-ray diffraction, multi-mineral interpretation), geochemical (X-ray fluorescence), statistical (non-metric multidimensional scaling analysis), and bedding dip and azimuth data, shed new light on the depositional facies and the spatial and temporal variability of the Opalinus Clay. Petrographic descriptions encompass nine new drill cores using a revised subfacies/facies classification scheme based on texture (colour, grain size, bedding) and composition (mineralogy). Particularly, one new subfacies (SF6) is described and interpreted as mass-wasting deposits. The drill cores are correlated laterally using specific marker horizons. This correlation is achieved by combining thorough facies investigations with lithostratigraphy, biostratigraphy, and chemostratigraphy. Six to seven small coarsening-upward cycles and two long-term coarsening-upward sequences can be interpreted as regressive trends. The observed trends are influenced by the interplay between sediment supply, eustatic sea level change, synsedimentary subsidence, but also the palaeogeographic configuration in an epicontinental sea, provenance and delivery of sediments, current dynamics and climate change. Finally, combined results show that the current dynamics in the Opalinus Clay has been underestimated until now and new depositional models, including the occurrence of drift deposits, are discussed.
{"title":"Facies variability and depositional cyclicity in central Northern Switzerland: insights from new Opalinus Clay drill cores","authors":"Géraldine N. Zimmerli, Stephan Wohlwend, Gaudenz Deplazes, Jens Becker, Andreas Wetzel, Fabio Francescangeli, Anneleen Foubert","doi":"10.1186/s00015-024-00463-6","DOIUrl":"https://doi.org/10.1186/s00015-024-00463-6","url":null,"abstract":"The Opalinus Clay, a silty to sandy claystone formation, Early to Middle Jurassic (Toarcian and Aalenian) in age, has been selected as the host rock for deep subsurface disposal of radioactive waste in Switzerland. Over the past thirty years, numerous geotechnical, mineralogical, and sedimentological studies have been conducted on the Opalinus Clay within the framework of the Nagra (National Cooperative for the Disposal of Radioactive Waste) deep drilling campaigns and the Mont Terri Project, an international research program dedicated to the study of claystone. The present study aims to unravel the variability of the lateral and vertical facies of the Opalinus Clay in central Northern Switzerland and to place this variability in a regional and basinal context. Analyses of new cores drilled in central Northern Switzerland, including petrographic, mineralogical (X-ray diffraction, multi-mineral interpretation), geochemical (X-ray fluorescence), statistical (non-metric multidimensional scaling analysis), and bedding dip and azimuth data, shed new light on the depositional facies and the spatial and temporal variability of the Opalinus Clay. Petrographic descriptions encompass nine new drill cores using a revised subfacies/facies classification scheme based on texture (colour, grain size, bedding) and composition (mineralogy). Particularly, one new subfacies (SF6) is described and interpreted as mass-wasting deposits. The drill cores are correlated laterally using specific marker horizons. This correlation is achieved by combining thorough facies investigations with lithostratigraphy, biostratigraphy, and chemostratigraphy. Six to seven small coarsening-upward cycles and two long-term coarsening-upward sequences can be interpreted as regressive trends. The observed trends are influenced by the interplay between sediment supply, eustatic sea level change, synsedimentary subsidence, but also the palaeogeographic configuration in an epicontinental sea, provenance and delivery of sediments, current dynamics and climate change. Finally, combined results show that the current dynamics in the Opalinus Clay has been underestimated until now and new depositional models, including the occurrence of drift deposits, are discussed.","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":"24 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190733","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 : 2024-09-12DOI: 10.1186/s00015-024-00460-9
Rafael Ferreiro Mählmann, Meinert Rahn, Sébastien Potel, Lan Nguyen-Thanh, Rainer Petschick
A collection of large data sets from different orogenic belts was compiled for a correlation between organic matter (OM) versus clay mineral (CM) indices calibrated with the vitrinite reflectance, (VR) vs Kübler-Indices (KI) method. Data selection was based on a normal geothermal gradient (25 to 35 °C/km) as determined in previous studies, e.g. by maturity modelling and clay mineral reaction progress calculations. In the Lower Austroalpine (Eastern Switzerland, European Alps) a 20 myr lasting metamorphic overprint caused an OM–CM thermal equilibrium among the indices used. The observed correlation enables to determine gradual changes in metamorphic factors such as pressure, temperature and time causing sensitive shifts of the gradient slope in the range of normal gradients. For New Caledonia, an identical correlation has been determined. Prior to re-equilibration of the VR/KI indices, sediments in New Caledonia of diagenetic to incipient metamorphic grade underwent a high-pressure subduction event. VR/KI indices are in or close to equilibrium, while slight differences in OM vs CM indices allow for a better understanding of polyphase conditions, especially with respect to pressure. Temperature estimations are identical despite of their poly-phase metamorphic history, which was mainly controlled by the last orogenic thermal event lasting > 5 to < 10 myr. In the eastern Helvetic Alps and Northern Calcareous Alps similar correlations were found with slightly different slopes. Comparison between different regions is possible when using KI standardization and same data discrimination. In both parts of the Alps a complex thermal history of short durations (< 5.0 myr for the Northern Calcareous Alps to 10 myr for the Helvetic Alps) caused similar VR/KI trends, but disequilibrium is suggested by weaker regression parameters. The following correlation is calculated for a moderate geotherm (55 to 74 mWm2, mean = 61 mWm2) and normal temperature gradient conditions (25 to 35 °Ckm−1): KI = 1.134e−0.305VR, (R2 = 0.880, n = 462) with VR given as %Rmax, KI as Δ°2θ (limited to values between 0.2 to 1.0 Δ°2θ). With increasing depth (z) a VR gradient of 1.4 ± 0.2%Rmaxkm−1 is determined and a KI gradient of 0.09 ± 0.002 Δ°2θ km−1 is observed. The study illustrates that a normal geotherm can be described by VR/KI correlation, even if different heating episodes may occur. For the detection of a poly-phase or plurifacial thermal history, several indices of clay minerals and organic matter with very different kinetics should be used, as e.g. demonstrated by strong differences in smectite content at equal VR/KI values versus structural depth. A specific interest is given to the correlation of vitrinite like solid bitumen reflectance as an alternative method to VR, the persistent preservation of liptinite macerals and the stability range of clay minerals and sub-greenschist facies critical minerals compared with VR/KI data. Until now, despite the Alps in this study, system
{"title":"Determination of a normal orogenic palaeo-geothermal gradient with clay mineral and organic matter indices: a review","authors":"Rafael Ferreiro Mählmann, Meinert Rahn, Sébastien Potel, Lan Nguyen-Thanh, Rainer Petschick","doi":"10.1186/s00015-024-00460-9","DOIUrl":"https://doi.org/10.1186/s00015-024-00460-9","url":null,"abstract":"A collection of large data sets from different orogenic belts was compiled for a correlation between organic matter (OM) versus clay mineral (CM) indices calibrated with the vitrinite reflectance, (VR) vs Kübler-Indices (KI) method. Data selection was based on a normal geothermal gradient (25 to 35 °C/km) as determined in previous studies, e.g. by maturity modelling and clay mineral reaction progress calculations. In the Lower Austroalpine (Eastern Switzerland, European Alps) a 20 myr lasting metamorphic overprint caused an OM–CM thermal equilibrium among the indices used. The observed correlation enables to determine gradual changes in metamorphic factors such as pressure, temperature and time causing sensitive shifts of the gradient slope in the range of normal gradients. For New Caledonia, an identical correlation has been determined. Prior to re-equilibration of the VR/KI indices, sediments in New Caledonia of diagenetic to incipient metamorphic grade underwent a high-pressure subduction event. VR/KI indices are in or close to equilibrium, while slight differences in OM vs CM indices allow for a better understanding of polyphase conditions, especially with respect to pressure. Temperature estimations are identical despite of their poly-phase metamorphic history, which was mainly controlled by the last orogenic thermal event lasting > 5 to < 10 myr. In the eastern Helvetic Alps and Northern Calcareous Alps similar correlations were found with slightly different slopes. Comparison between different regions is possible when using KI standardization and same data discrimination. In both parts of the Alps a complex thermal history of short durations (< 5.0 myr for the Northern Calcareous Alps to 10 myr for the Helvetic Alps) caused similar VR/KI trends, but disequilibrium is suggested by weaker regression parameters. The following correlation is calculated for a moderate geotherm (55 to 74 mWm2, mean = 61 mWm2) and normal temperature gradient conditions (25 to 35 °Ckm−1): KI = 1.134e−0.305VR, (R2 = 0.880, n = 462) with VR given as %Rmax, KI as Δ°2θ (limited to values between 0.2 to 1.0 Δ°2θ). With increasing depth (z) a VR gradient of 1.4 ± 0.2%Rmaxkm−1 is determined and a KI gradient of 0.09 ± 0.002 Δ°2θ km−1 is observed. The study illustrates that a normal geotherm can be described by VR/KI correlation, even if different heating episodes may occur. For the detection of a poly-phase or plurifacial thermal history, several indices of clay minerals and organic matter with very different kinetics should be used, as e.g. demonstrated by strong differences in smectite content at equal VR/KI values versus structural depth. A specific interest is given to the correlation of vitrinite like solid bitumen reflectance as an alternative method to VR, the persistent preservation of liptinite macerals and the stability range of clay minerals and sub-greenschist facies critical minerals compared with VR/KI data. Until now, despite the Alps in this study, system","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":"24 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190737","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 : 2024-09-02DOI: 10.1186/s00015-024-00464-5
Matija Vukovski, Marko Špelić, Duje Kukoč, Tamara Troskot-Čorbić, Tonći Grgasović, Damir Slovenec, Bruno Tomljenović
A comprehensive study, including geological mapping, structural and thermochronological analysis, has been carried out on Ivanščica Mountain (NW Croatia), with the aim to reconstruct the tectonic history of the Dinarides, Southern/Eastern Alps and Pannonian Basin transitional zone. Implementation of structural and thermochronological methods enabled a subdivision of Ivanščica Mt. into two structural domains (from bottom to top): Ivanščica Parautochthon and Ivanščica Imbricate Fan and Cenozoic sedimentary cover. In addition, a sequence of deformational events in tectonic history of this transitional zone is proposed, comprising three extensional and four contractional events starting from Middle Triassic until present times. The two oldest deformational events indicate Middle Triassic (D1) and Early Jurassic (D2) extensional pulses and only occur in volcano-sedimentary successions of the Ivanščica Mt. The oldest contractional event (D3) is related to the obduction of a Neotethyan ophiolitic mélange over an Upper Triassic to Lower Cretaceous succession of the eastern margin of the Adriatic microplate, which resulted in thermal overprint of the Ivanščica Imbricate Fan structural domain in Berriasian—Valanginian times (~ 140 Ma). This event was soon followed by a second contractional event (D4), which resulted in thrusting and imbrication of the Adriatic passive margin successions together with previously emplaced ophiolitic mélange, thermal overprint of the footwall successions, fast exhumation and erosion. Apatite fission track data together with syn-tectonic deposits indicate an Hauterivian to Albian age of this D4 event (~ 133–100 Ma). These Mesozoic structures were dextrally rotated in post-Oligocene times and brought from the initially typically Dinaridic SE striking and SW verging structures to the recent SW striking and NW verging structures. The following extensional event (D5) is associated with the formation of SE striking and mostly NE dipping normal listric faults, and ENE striking dextral faults accommodating top-NE extension in the Pannonian Basin. Deformations were coupled with hanging wall sedimentation of Ottnangian to middle Badenian (middle Burdigalian to upper Langhian; ~ 18–14 Ma) syn-rift deposit as observed from the reflection seismic and well data. A short-lasting contraction (D6) was registered in the late Sarmatian (late Serravallian; ~ 12 Ma). The youngest documented deformational event (D7) resulted in reactivation of ENE striking dextral faults, formation of SE striking dextral faults as well as the formation of E to ENE trending folds and reverse faults. This event corresponds to late Pannonian (late Messinian; ~ 6 Ma) to Present NNW-SSE contraction driven by the indentation and counterclockwise rotation of Adriatic microplate. Recognized tectonic events and their timings indicate that Ivanščica was mainly affected by deformational phases related to the Mesozoic evolution of the Neotethys Ocean as well as Cenozoic openi
对伊万什奇卡山（克罗地亚西北部）进行了包括地质测绘、结构和热时学分析在内的综合研究，目的是重建迪纳里德斯山脉、南阿尔卑斯山/东阿尔卑斯山和潘诺尼亚盆地过渡带的构造历史。采用构造和热时学方法将伊万什奇卡山划分为两个构造域（从下到上）：伊万尼什奇卡副褶皱岩（Ivanščica Parautochthon）和伊万尼什奇卡覆岩扇及新生代沉积覆盖层。此外，还提出了该过渡带构造史上的变形事件序列，包括从中三叠世至今的三次伸展事件和四次收缩事件。最古老的两个变形事件是中三叠世（D1）和早侏罗世（D2）的伸展脉冲，仅出现在伊万什奇卡山的火山沉积岩层中。最古老的收缩事件（D3）与亚得里亚海微板块东缘上三叠世至下白垩世演替上的新特提山脉蛇绿混杂岩的俯冲有关，这导致了贝里亚-瓦朗基尼时代（约 140 Ma）伊万希奇卡覆盆扇构造域的热覆盖。在这一事件之后不久，又发生了第二次收缩事件（D4），导致亚得里亚海被动边缘岩层与之前沉积的蛇绿岩交错、岩脚岩层热压、快速掘起和侵蚀。磷灰石裂变轨迹数据以及同步构造沉积物表明，这一 D4 事件的年代为豪特里维纪至阿尔卑斯纪（约 133-100 Ma）。这些中生代构造在后更新世时期发生了右旋，并从最初典型的迪纳拉东南向和西南向构造转变为近期的西南向和西北向构造。接下来的延伸事件（D5）与潘诺尼亚盆地中形成的东南走向、大部分为东北倾角的正断层和东偏东走向的右旋断层有关，这些断层可容纳顶部向东北方向的延伸。从反射地震和油井数据中观察到，变形与奥特南安期至巴登中期（伯蒂加里中期至朗希安上期；约 18-14 Ma）同步裂谷沉积的悬壁沉积作用相耦合。在萨尔马特晚期（Serravallian 晚期；约 12 Ma）出现了短暂的收缩（D6）。有记载的最年轻的变形事件（D7）导致 ENE 向的右旋断层重新活跃，形成 SE 向的右旋断层，并形成 E 至 ENE 走向的褶皱和逆断层。这一事件与潘诺尼亚晚期（梅西尼亚晚期；约 6 Ma）至目前的 NNW-SSE 收缩相吻合，其驱动力是亚得里亚海微板块的缩进和逆时针旋转。公认的构造事件及其时间表明，伊万希奇卡主要受到与新特提斯洋中生代演化以及潘诺尼亚盆地新生代开裂和反转有关的变形阶段的影响。因此，伊万希奇卡山的中生代构造沉积演化证明了其非玢岩中生代构造地层实体与迪纳利山脉前喀斯特单元的古地理关联。
{"title":"Unravelling the tectonic evolution of the Dinarides—Alps—Pannonian Basin transition zone: insights from structural analysis and low-temperature thermochronology from Ivanščica Mt., NW Croatia","authors":"Matija Vukovski, Marko Špelić, Duje Kukoč, Tamara Troskot-Čorbić, Tonći Grgasović, Damir Slovenec, Bruno Tomljenović","doi":"10.1186/s00015-024-00464-5","DOIUrl":"https://doi.org/10.1186/s00015-024-00464-5","url":null,"abstract":"A comprehensive study, including geological mapping, structural and thermochronological analysis, has been carried out on Ivanščica Mountain (NW Croatia), with the aim to reconstruct the tectonic history of the Dinarides, Southern/Eastern Alps and Pannonian Basin transitional zone. Implementation of structural and thermochronological methods enabled a subdivision of Ivanščica Mt. into two structural domains (from bottom to top): Ivanščica Parautochthon and Ivanščica Imbricate Fan and Cenozoic sedimentary cover. In addition, a sequence of deformational events in tectonic history of this transitional zone is proposed, comprising three extensional and four contractional events starting from Middle Triassic until present times. The two oldest deformational events indicate Middle Triassic (D1) and Early Jurassic (D2) extensional pulses and only occur in volcano-sedimentary successions of the Ivanščica Mt. The oldest contractional event (D3) is related to the obduction of a Neotethyan ophiolitic mélange over an Upper Triassic to Lower Cretaceous succession of the eastern margin of the Adriatic microplate, which resulted in thermal overprint of the Ivanščica Imbricate Fan structural domain in Berriasian—Valanginian times (~ 140 Ma). This event was soon followed by a second contractional event (D4), which resulted in thrusting and imbrication of the Adriatic passive margin successions together with previously emplaced ophiolitic mélange, thermal overprint of the footwall successions, fast exhumation and erosion. Apatite fission track data together with syn-tectonic deposits indicate an Hauterivian to Albian age of this D4 event (~ 133–100 Ma). These Mesozoic structures were dextrally rotated in post-Oligocene times and brought from the initially typically Dinaridic SE striking and SW verging structures to the recent SW striking and NW verging structures. The following extensional event (D5) is associated with the formation of SE striking and mostly NE dipping normal listric faults, and ENE striking dextral faults accommodating top-NE extension in the Pannonian Basin. Deformations were coupled with hanging wall sedimentation of Ottnangian to middle Badenian (middle Burdigalian to upper Langhian; ~ 18–14 Ma) syn-rift deposit as observed from the reflection seismic and well data. A short-lasting contraction (D6) was registered in the late Sarmatian (late Serravallian; ~ 12 Ma). The youngest documented deformational event (D7) resulted in reactivation of ENE striking dextral faults, formation of SE striking dextral faults as well as the formation of E to ENE trending folds and reverse faults. This event corresponds to late Pannonian (late Messinian; ~ 6 Ma) to Present NNW-SSE contraction driven by the indentation and counterclockwise rotation of Adriatic microplate. Recognized tectonic events and their timings indicate that Ivanščica was mainly affected by deformational phases related to the Mesozoic evolution of the Neotethys Ocean as well as Cenozoic openi","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":"43 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190736","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}
<p>This Special Issue of the Swiss Journal of Geosciences entitled “<i>Evolution of collisional orogens in space and time: the Alpine-Himalayan system in 4 dimensions</i>”, was proposed during the joint meeting “Geosciences for a sustainable future” organized by the Società Geologica Italiana and Società Italiana di Mineralogia e Petrografia held in Turin (Italy) in September 2022.</p><p>The issue focuses on the evolution of collisional orogens through a multidisciplinary approach. As a matter of fact, continental plate collisions give rise to collisional-related orogenic belts that are some of the most spectacular and dominant features on our planet.</p><p>During collision of continental plates, considerable deformation occurs with large scale overthrusting, burial and metamorphism of continental lithosphere portions. The final anatomy and the shape of collisional belts are highly diverse, due to the interactions of several controlling factors, including the pre-collisional tectonic history, the rate and the angle of convergence, the mechanical strength and thermal state of the involved colliding plates.</p><p>The youngest collisional system on Earth is the Alpine-Himalayan belt, extending from Spain to Southeast Asia. Its general structure was first described by Emile Argand in "La tectonique de l’Asie". On the occasion of the centenary of Argand’s work, presented during the XIII International Geological congress in Belgium (August 10, 1922), this thematic volume aims to provide an updated view on the Alpine-Himalayan geology.</p><p>This Special Issue collects multidisciplinary contributions focusing on the Alpine-Himalayan system, dealing with the reconstruction of the tectonic architecture at different scales, integrating field mapping to microscale and describing the tectono-metamorphic evolution.</p><p>The papers included in this collection span from the Himalaya to the Western, Central and Ligurian Alps and also include a paper on the Alborz Mountains in Iran.</p><p>The publication by Robyr (2023) brings us in the Himalayan belt (Miyar Valley, North-West India) and focuses on the old history of the belt studying the pre-Himalayan metamorphism of the metamorphic core of the chain, until now strongly debated. Through phase petrology and microtectonics studies, combined with valuable field data, Robyr demonstrates the existence of a pre-Himalayan orogenic cycle.</p><p>Pantet et al. (2024), focus on the region surrounding the Zermatt area (SW Switzerland and NW Italy) where continental and oceanic units are strongly imbricated. Starting from a very detailed field mapping, they focus on the structure and stratigraphy of the Permian-Jurassic continent‑derived Faisceau Vermiculaire series and associated non-ophiolitic Upper Cretaceous calcschists (Série Rousse), both intercalated within ophiolitic units. They were able to reconstruct the architecture of the Briançonnais-Prepiemont palaeomargin before the onset of Alpine deformation and the struct
(2023) 带我们回到亚洲，回到伊朗北部的阿尔伯兹山脉。他们研究了加什特-马苏莱赫地区侵入古生代玄武岩和中生代沉积物的辉长岩。借助岩相分析、整岩和矿物化学以及地质年代学，作者们能够将该地区的镁质岩浆活动与白垩纪中期新特提斯俯冲板块滚回所产生的远场效应导致的延伸联系起来。我们还非常感谢审稿人，他们为提高稿件质量做出了巨大贡献，并为本特刊的成功出版提供了帮助。俯冲被动边缘的结构和变质演化：来自西阿尔卑斯山脉布赖恩聪奈山系（Ubaye-Maira 山谷，法国-意大利）的启示。Swiss Journal of Geosciences, 116, 18.Article Google Scholar Manna, L., Perozzo, M., Menegoni, N., Tamburelli, S., Crispini, L., Federico, L., Seno, S., & Maino, M. (2023).控制利古里亚阿尔卑斯山（意大利西北部）上新世弯曲的千米级断层带剖面图：Anomy of a km-scale fault zone controlling the Oligo-Miocene bending of the Ligurian Alps (NW Italy): integration of field and 3D high-resolution digital outcrop model data.Swiss Journal of Geosciences, 116, 15.Article Google Scholar Pantet, A., Epard, J.-L., & Masson, H. (2024).采尔马特周围蛇绿混杂岩中的大陆成因变质岩（Cimes Blanches 和 Frilihorn）：Relations with the Mischabel backfold and Mont Fort nappe (Pennine Alps).Swiss Journal of Geosciences, 117, 10.Article Google Scholar Rezaei, L., Timmerman, M. J., Moazzen, M., Altenberger, U., Sláma, J., Sudo, M., Günter, C., Wilke, F. D. H., & Schleicher, A. M. (2023).Mid-Cretaceous extension magmatism in the Alborz Mountains, north Iran; geochemistry and geochronology of Gasht-Masuleh gabbros.Swiss Journal of Geosciences, 116, 14.Article CAS Google Scholar Robyr, M. (2023).印度西北部米亚尔山谷喜马拉雅高山结晶前变质作用的证据》。瑞士地球科学杂志》，116，17.文章 谷歌学者 Zanchetta, S., Crippa, C., Zanchi, A., & Montemagni, C. (2024).Val Biandino 侵入岩组（意大利北部南阿尔卑斯山中部）：关于南阿尔卑斯山岩浆活动的新地质年代和地球化学数据。瑞士地球科学杂志》，117, 7。Article CAS Google Scholar Download references作者和工作单位Earth Sciences Department, University of Turin, Via Valperga Caluso 35, 10125, Turin, ItalyChiara Montomoli &；Salvatore IaccarinoInstitute of Earth Sciences, University of Lausanne, Géopolis Building, CH-1015, Lausanne, SwitzerlandJean-Luc EpardDepartment of Geological Sciences, Stockholm University, 106 91, Stockholm、瑞典Paola Manzotti作者Chiara Montomoli查看作者发表的论文您也可以在PubMed Google Scholar中搜索该作者Salvatore Iaccarino查看作者发表的论文您也可以在PubMed Google Scholar中搜索该作者Jean-Luc Epard查看作者发表的论文您也可以在PubMed Google Scholar中搜索该作者Paola Manzotti查看作者发表的论文您也可以在PubMed Google Scholar中搜索该作者ContributionsCM撰写、编辑；SI撰写、编辑；JLE撰写、编辑；PM撰写、编辑。开放获取本文采用知识共享署名 4.0 国际许可协议进行许可，该协议允许以任何媒介或格式使用、共享、改编、分发和复制，只要您适当注明原作者和来源，提供知识共享许可协议的链接，并说明是否进行了修改。本文中的图片或其他第三方材料均包含在文章的知识共享许可协议中，除非在材料的署名栏中另有说明。如果材料未包含在文章的知识共享许可协议中，且您打算使用的材料不符合法律规定或超出许可使用范围，则您需要直接从版权所有者处获得许可。要查看该许可的副本，请访问 http://creativecommons.org/licenses/by/4.0/.Reprints and permissionsCite this articleMontomoli, C., Iaccarino, S., Epard, JL. et al. Special Issue：碰撞造山运动在空间和时间上的演变--阿尔卑斯-喜马拉雅四维系统。Swiss J Geosci 117, 14 (2024). https://doi.org/10.1186/s00015-024-00466-3Download citationPublished: 29 August 2024DOI: https://doi.org/10.
{"title":"Special Issue: Evolution of collisional orogens in space and time—the Alpine-Himalayan system in 4 dimensions","authors":"Chiara Montomoli, Salvatore Iaccarino, Jean-Luc Epard, Paola Manzotti","doi":"10.1186/s00015-024-00466-3","DOIUrl":"https://doi.org/10.1186/s00015-024-00466-3","url":null,"abstract":"<p>This Special Issue of the Swiss Journal of Geosciences entitled “<i>Evolution of collisional orogens in space and time: the Alpine-Himalayan system in 4 dimensions</i>”, was proposed during the joint meeting “Geosciences for a sustainable future” organized by the Società Geologica Italiana and Società Italiana di Mineralogia e Petrografia held in Turin (Italy) in September 2022.</p><p>The issue focuses on the evolution of collisional orogens through a multidisciplinary approach. As a matter of fact, continental plate collisions give rise to collisional-related orogenic belts that are some of the most spectacular and dominant features on our planet.</p><p>During collision of continental plates, considerable deformation occurs with large scale overthrusting, burial and metamorphism of continental lithosphere portions. The final anatomy and the shape of collisional belts are highly diverse, due to the interactions of several controlling factors, including the pre-collisional tectonic history, the rate and the angle of convergence, the mechanical strength and thermal state of the involved colliding plates.</p><p>The youngest collisional system on Earth is the Alpine-Himalayan belt, extending from Spain to Southeast Asia. Its general structure was first described by Emile Argand in \"La tectonique de l’Asie\". On the occasion of the centenary of Argand’s work, presented during the XIII International Geological congress in Belgium (August 10, 1922), this thematic volume aims to provide an updated view on the Alpine-Himalayan geology.</p><p>This Special Issue collects multidisciplinary contributions focusing on the Alpine-Himalayan system, dealing with the reconstruction of the tectonic architecture at different scales, integrating field mapping to microscale and describing the tectono-metamorphic evolution.</p><p>The papers included in this collection span from the Himalaya to the Western, Central and Ligurian Alps and also include a paper on the Alborz Mountains in Iran.</p><p>The publication by Robyr (2023) brings us in the Himalayan belt (Miyar Valley, North-West India) and focuses on the old history of the belt studying the pre-Himalayan metamorphism of the metamorphic core of the chain, until now strongly debated. Through phase petrology and microtectonics studies, combined with valuable field data, Robyr demonstrates the existence of a pre-Himalayan orogenic cycle.</p><p>Pantet et al. (2024), focus on the region surrounding the Zermatt area (SW Switzerland and NW Italy) where continental and oceanic units are strongly imbricated. Starting from a very detailed field mapping, they focus on the structure and stratigraphy of the Permian-Jurassic continent‑derived Faisceau Vermiculaire series and associated non-ophiolitic Upper Cretaceous calcschists (Série Rousse), both intercalated within ophiolitic units. They were able to reconstruct the architecture of the Briançonnais-Prepiemont palaeomargin before the onset of Alpine deformation and the struct","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":"51 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190740","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 : 2024-08-28DOI: 10.1186/s00015-024-00465-4
Leila Rezaei, Martin J. Timmerman, Uwe Altenberger, Mohssen Moazzen, Franziska D. H. Wilke, Christina Günter, Masafumi Sudo, Jiří Sláma
The Alborz Mountains in north Iran underwent several tectono-metamorphic events during opening and closure of the Palaeotethys and Neotethys Oceans. These events are recorded by rare and discontinuously exposed metamorphic rocks, such as the HP-LT Asalem-Shanderman Complex and the Gasht Metamorphic Complex (GMC), that are considered to have been metamorphosed during the closure of the Palaeotethys Ocean. The GMC comprises poorly exposed metasediments and amphibolites metamorphosed under greenschist- to amphibolite-facies conditions, along with smaller volumes of granites. Different dating methods were applied to selected samples of the GMC basement to constrain the geological evolution of this part of the Alborz Mountains. A metagranite yielded two LA-ICP-MS U–Pb zircon ages of 638.4 ± 4.1 Ma and 590.3 ± 4.8 Ma that possibly date protolith crystallisation and later deformation and metamorphism, respectively, and a granite yielded a late Ediacaran 551 ± 2.5 Ma U–Pb zircon crystallisation age. A northern provenance from the basement to the South Caspian Basin can neither be established nor ruled out because no age data are available for this unit. Derivation of the GMC from Turan Block basement is unlikely, as this has a different crustal makeup and is probably composed of Paleoproterozoic and early Neoproterozoic material. The zircon ages are similar to published ages from the Arabian-Nubian Shield, indicating that this part of the Alborz basement may have belonged to the northern margin of Gondwana in the Neoproterozoic before rifting and drifting away along with other Iranian blocks (the Cimmerian terranes) during opening of the Neotethys Ocean. Chemical Th-U-total Pb ages for metamorphic monazites from two metapelite samples yielded a very large range of spot ages, of which c. 80% falls between 200 and 250 Ma, that do not allow to distinguish between Eo-Cimmerian and Main Cimmerian events in the GMC. However, they may indicate that the amphibolite-facies peak metamorphism of the GMC occurred sometime in the Triassic, in any case much later than the Carboniferous metamorphism in the neighbouring Asalem-Shanderman Metamorphic Complex to the north. Peak-metamorphic amphibole from amphibolite, retrograde white mica and foliation-defining biotite from metapelites and magmatic white mica from granite yielded much younger 175.1 ± 0.5 to 177.0 ± 0.4 Ma 40Ar/39Ar plateau ages. The Toarcian 40Ar/39Ar ages for minerals with different nominal closure temperatures reflect very rapid cooling of GMC basement below the Shemshak Group due to extension-triggered uplift. This late Toarcian to Aalenian extension event can be correlated with the regional Mid-Cimmerian unconformity of mid-Bajocian age (c. 170 Ma) that resulted from the tectonic movements causing rapid uplift and erosion. Extension probably started in the western Alborz Mountains in the Toarcian, migrated eastward, and culminated in the Aalenian in the eastern Alborz with the formation of a deep-mari
{"title":"Ediacaran to Jurassic geodynamic evolution of the Alborz Mountains, north Iran: geochronological data from the Gasht Metamorphic Complex","authors":"Leila Rezaei, Martin J. Timmerman, Uwe Altenberger, Mohssen Moazzen, Franziska D. H. Wilke, Christina Günter, Masafumi Sudo, Jiří Sláma","doi":"10.1186/s00015-024-00465-4","DOIUrl":"https://doi.org/10.1186/s00015-024-00465-4","url":null,"abstract":"The Alborz Mountains in north Iran underwent several tectono-metamorphic events during opening and closure of the Palaeotethys and Neotethys Oceans. These events are recorded by rare and discontinuously exposed metamorphic rocks, such as the HP-LT Asalem-Shanderman Complex and the Gasht Metamorphic Complex (GMC), that are considered to have been metamorphosed during the closure of the Palaeotethys Ocean. The GMC comprises poorly exposed metasediments and amphibolites metamorphosed under greenschist- to amphibolite-facies conditions, along with smaller volumes of granites. Different dating methods were applied to selected samples of the GMC basement to constrain the geological evolution of this part of the Alborz Mountains. A metagranite yielded two LA-ICP-MS U–Pb zircon ages of 638.4 ± 4.1 Ma and 590.3 ± 4.8 Ma that possibly date protolith crystallisation and later deformation and metamorphism, respectively, and a granite yielded a late Ediacaran 551 ± 2.5 Ma U–Pb zircon crystallisation age. A northern provenance from the basement to the South Caspian Basin can neither be established nor ruled out because no age data are available for this unit. Derivation of the GMC from Turan Block basement is unlikely, as this has a different crustal makeup and is probably composed of Paleoproterozoic and early Neoproterozoic material. The zircon ages are similar to published ages from the Arabian-Nubian Shield, indicating that this part of the Alborz basement may have belonged to the northern margin of Gondwana in the Neoproterozoic before rifting and drifting away along with other Iranian blocks (the Cimmerian terranes) during opening of the Neotethys Ocean. Chemical Th-U-total Pb ages for metamorphic monazites from two metapelite samples yielded a very large range of spot ages, of which c. 80% falls between 200 and 250 Ma, that do not allow to distinguish between Eo-Cimmerian and Main Cimmerian events in the GMC. However, they may indicate that the amphibolite-facies peak metamorphism of the GMC occurred sometime in the Triassic, in any case much later than the Carboniferous metamorphism in the neighbouring Asalem-Shanderman Metamorphic Complex to the north. Peak-metamorphic amphibole from amphibolite, retrograde white mica and foliation-defining biotite from metapelites and magmatic white mica from granite yielded much younger 175.1 ± 0.5 to 177.0 ± 0.4 Ma 40Ar/39Ar plateau ages. The Toarcian 40Ar/39Ar ages for minerals with different nominal closure temperatures reflect very rapid cooling of GMC basement below the Shemshak Group due to extension-triggered uplift. This late Toarcian to Aalenian extension event can be correlated with the regional Mid-Cimmerian unconformity of mid-Bajocian age (c. 170 Ma) that resulted from the tectonic movements causing rapid uplift and erosion. Extension probably started in the western Alborz Mountains in the Toarcian, migrated eastward, and culminated in the Aalenian in the eastern Alborz with the formation of a deep-mari","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":"39 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190738","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 : 2024-06-17DOI: 10.1186/s00015-024-00456-5
Martin K. Reiser, Ralf Schuster, Christoph Iglseder, Daniela Gallhofer, Josef Nievoll
The Troiseck-Floning and Rosskogel nappes are part of the Austroalpine Unit in the eastern part of the Eastern Alps. The nappes are in tectonic contact and comprise Permian to Mesozoic lower greenschist facies metamorphic metasediments, but only the Troiseck-Floning Nappe consists of a pre-Permian crystalline basement (Troiseck Complex) as well. LA-ICP-MS U–Pb zircon ages, Rb–Sr biotite ages and geochemical data unravel the geological evolution of these tectonic units from Neoproterozoic to Mesozoic times. Detrital U–Pb zircon analyses from siliciclastic metasediments of the Troiseck Complex indicate a late Ediacaran to early Cambrian deposition age of the volcanoclastic sequence. The age distribution correlates with a position along the northeastern Gondwana margin. A late Cambrian crystallization age (502.4 ± 6.8 Ma) of granitic intrusions together with evidence for Late Cambrian/Ordovician magmatism and metamorphism indicate a position at an active plate margin. Polyphase overprinting during the Variscan orogeny is recorded by Late Devonian/early Carboniferous pegmatite dikes (~ 353 Ma) that formed after an early Variscan event, while Pennsylvanian ages of overgrowth rims and inherited grains (~ 320 Ma) are evidence for late Variscan metamorphism. Rhyolitic to andesitic volcanic rocks from the Troiseck-Floning and Rosskogel nappes (271–264 Ma) concomitant with intrusions of porphyric granitoids now transformed to augen gneiss (271 Ma) yield evidence for Permian rift-related magmatism that is widely reported from the Eastern Alps and Western Carpathians. Rb–Sr biotite ages (75–74 Ma) indicate Late Cretaceous cooling below c. 300 °C. This relates to Late Cretaceous exhumation of the Troiseck-Floning Nappe following an Eo-Alpine metamorphic overprint at lower greenschist-facies metamorphic conditions. Based on the similar lithostratigraphy, analogous geological evolution and structure, the Troiseck-Floning Nappe represents the lateral extension of the Seckau Nappe. The new dataset also allows for correlations with other basement complexes that occur in the Western Carpathians.
{"title":"Geochronology, geochemistry, and geological evolution of the Troiseck-Floning and Rosskogel nappes (Eastern Alps): unraveling parallels between the Eastern Alps and Western Carpathians","authors":"Martin K. Reiser, Ralf Schuster, Christoph Iglseder, Daniela Gallhofer, Josef Nievoll","doi":"10.1186/s00015-024-00456-5","DOIUrl":"https://doi.org/10.1186/s00015-024-00456-5","url":null,"abstract":"The Troiseck-Floning and Rosskogel nappes are part of the Austroalpine Unit in the eastern part of the Eastern Alps. The nappes are in tectonic contact and comprise Permian to Mesozoic lower greenschist facies metamorphic metasediments, but only the Troiseck-Floning Nappe consists of a pre-Permian crystalline basement (Troiseck Complex) as well. LA-ICP-MS U–Pb zircon ages, Rb–Sr biotite ages and geochemical data unravel the geological evolution of these tectonic units from Neoproterozoic to Mesozoic times. Detrital U–Pb zircon analyses from siliciclastic metasediments of the Troiseck Complex indicate a late Ediacaran to early Cambrian deposition age of the volcanoclastic sequence. The age distribution correlates with a position along the northeastern Gondwana margin. A late Cambrian crystallization age (502.4 ± 6.8 Ma) of granitic intrusions together with evidence for Late Cambrian/Ordovician magmatism and metamorphism indicate a position at an active plate margin. Polyphase overprinting during the Variscan orogeny is recorded by Late Devonian/early Carboniferous pegmatite dikes (~ 353 Ma) that formed after an early Variscan event, while Pennsylvanian ages of overgrowth rims and inherited grains (~ 320 Ma) are evidence for late Variscan metamorphism. Rhyolitic to andesitic volcanic rocks from the Troiseck-Floning and Rosskogel nappes (271–264 Ma) concomitant with intrusions of porphyric granitoids now transformed to augen gneiss (271 Ma) yield evidence for Permian rift-related magmatism that is widely reported from the Eastern Alps and Western Carpathians. Rb–Sr biotite ages (75–74 Ma) indicate Late Cretaceous cooling below c. 300 °C. This relates to Late Cretaceous exhumation of the Troiseck-Floning Nappe following an Eo-Alpine metamorphic overprint at lower greenschist-facies metamorphic conditions. Based on the similar lithostratigraphy, analogous geological evolution and structure, the Troiseck-Floning Nappe represents the lateral extension of the Seckau Nappe. The new dataset also allows for correlations with other basement complexes that occur in the Western Carpathians.","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":"20 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500738","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 : 2024-06-04DOI: 10.1186/s00015-024-00455-6
Adrien Pantet, Jean-Luc Epard, Henri Masson
The region surrounding Zermatt (SW Switzerland and NW Italy) displays some classic examples of imbrications between continental and oceanic units. In particular, the studied units, called Cimes Blanches and Frilihorn or Faisceau Vermiculaire, consist of a set of thin bands of continent-derived metasediments intercalated at different levels within the ocean-derived units. These bands are locally reduced to only one meter thick but can be traced for several tens to more than one hundred kilometers across the Pennine Alps. The mechanisms leading to such imbrications are a long-standing and still-debated question. Based on detailed mapping and structural analysis of key areas, we present new data on the structure and stratigraphy of the Faisceau Vermiculaire in the area surrounding Zermatt, with particular focus on the Täschalpen sector, where the Faisceau Vermiculaire is locally in contact with basement units. Our observations allow: (i) to confirm the presence of widespread breccias of probable Jurassic age in the Faisceau Vermiculaire; (ii) to interpret the contacts between the Faisceau Vermiculaire and the overlying non-ophiolitic Schistes Lustrés (Série Rousse) as stratigraphic; (iii) to show that the stratigraphy of the Faisceau Vermiculaire and associated Série Rousse contrasts strongly with the cover of the Siviez-Mischabel nappe and that these sequences originate from different paleogeographic domains (Prepiemont basin and Briançonnais platform respectively); (iv) to interpret as stratigraphic the contact of the Faisceau Vermiculaire and the Série Rousse with the basement forming the Alphubel anticline; the local unconformity is interpreted as the result of the activity of synsedimentary Jurassic normal paleofaults; (v) to highlight the trace of a major Jurassic normal fault, that should have marked an abrupt thinning of the paleomargin; it corresponds now to the contact between the Faisceau Vermiculaire (and associated Série Rousse) and the Siviez-Mischabel basement in the hinge of the Mischabel backfold. We propose a new tectonic scheme for the structure of the Faisceau Vermiculaire and adjacent units involving an early northward folding of the Faisceau Vermiculaire with the Série Rousse and the ophiolitic Schistes Lustrés of the Tsaté nappe, followed by major backfolding responsible for the southward emplacement of these units above the HP Zermatt-Saas and Monte Rosa nappes. Our study at regional scale shows that the group formed by the Alphubel basement, the Faisceau Vermiculaire and the Série Rousse share a tectonic position and stratigraphic sequences identical to those of the Mont Fort nappe, which outcrops on the other side of the Dent Blanche klippe. It leads to the proposition that this group constitutes the eastern extension of the Mont Fort nappe.
采尔马特（瑞士西南部和意大利西北部）周边地区展示了大陆和海洋单元交错的一些典型例子。特别是，所研究的称为 Cimes Blanches 和 Frilihorn 或 Faisceau Vermiculaire 的单元，由一组源于大陆的变质岩薄带组成，这些薄带在不同层面上夹杂在源于海洋的单元中。这些薄带在局部地区厚度仅为一米，但在整个宾夕法尼亚阿尔卑斯山脉却可以追溯几十公里到一百多公里。导致这种交错的机制是一个长期存在且仍有争议的问题。基于对关键区域的详细测绘和结构分析，我们提供了采尔马特周边地区褶皱岩的结构和地层学新数据，尤其侧重于 Täschalpen 地区，在该地区褶皱岩与基底单元局部接触。我们的观测结果有助于(i) 确认在褶皱岩中广泛存在可能是侏罗纪的角砾岩；(ii) 将褶皱岩与上覆非沸石片岩（Série Rousse）之间的接触解释为地层接触；(iii) 表明 Faisceau Vermiculaire 地层和相关的 Série Rousse 地层与 Siviez-Mischabel 断层的覆盖层形成强烈反差，这些地层源自不同的古地理区域（分别为 Prepiemont 盆地和 Briançonnais 平台）；(iv) 从地层学角度解释 Faisceau Vermiculaire 和 Série Rousse 与形成 Alphubel 反断裂的基底的接触；将当地的不整合解释为侏罗系合 成岩正常古断层活动的结果；(v) 突出侏罗纪大正断层的痕迹，该断层本应标志着古边际的突然变薄；现在该断层相当于 Faisceau Vermiculaire（及相关的 Série Rousse）与米沙贝尔背褶铰接处的 Siviez-Mischabel 基底之间的接触。我们为 Faisceau Vermiculaire 及其邻近单元的构造提出了一个新的构造方案，其中包括 Faisceau Vermiculaire 早期与 Série Rousse 和 Tsaté 网状地层的蛇绿岩 Schistes Lustrés 一起向北褶皱，随后发生大的反褶，导致这些单元向南隆起于 HP Zermatt-Saas 和 Monte Rosa 网状地层之上。我们在区域范围内进行的研究表明，由阿尔弗贝尔基底、费斯索侏罗纪和塞里鲁兹形成的岩组，其构造位置和地层序列与出露于登特布兰奇地块另一侧的蒙堡岩层相同。由此可以推断，该岩组构成了蒙堡岩层的东延部分。
{"title":"Continent-derived metasediments (Cimes Blanches and Frilihorn) within the ophiolites around Zermatt: relations with the Mischabel backfold and Mont Fort nappe (Pennine Alps)","authors":"Adrien Pantet, Jean-Luc Epard, Henri Masson","doi":"10.1186/s00015-024-00455-6","DOIUrl":"https://doi.org/10.1186/s00015-024-00455-6","url":null,"abstract":"The region surrounding Zermatt (SW Switzerland and NW Italy) displays some classic examples of imbrications between continental and oceanic units. In particular, the studied units, called Cimes Blanches and Frilihorn or Faisceau Vermiculaire, consist of a set of thin bands of continent-derived metasediments intercalated at different levels within the ocean-derived units. These bands are locally reduced to only one meter thick but can be traced for several tens to more than one hundred kilometers across the Pennine Alps. The mechanisms leading to such imbrications are a long-standing and still-debated question. Based on detailed mapping and structural analysis of key areas, we present new data on the structure and stratigraphy of the Faisceau Vermiculaire in the area surrounding Zermatt, with particular focus on the Täschalpen sector, where the Faisceau Vermiculaire is locally in contact with basement units. Our observations allow: (i) to confirm the presence of widespread breccias of probable Jurassic age in the Faisceau Vermiculaire; (ii) to interpret the contacts between the Faisceau Vermiculaire and the overlying non-ophiolitic Schistes Lustrés (Série Rousse) as stratigraphic; (iii) to show that the stratigraphy of the Faisceau Vermiculaire and associated Série Rousse contrasts strongly with the cover of the Siviez-Mischabel nappe and that these sequences originate from different paleogeographic domains (Prepiemont basin and Briançonnais platform respectively); (iv) to interpret as stratigraphic the contact of the Faisceau Vermiculaire and the Série Rousse with the basement forming the Alphubel anticline; the local unconformity is interpreted as the result of the activity of synsedimentary Jurassic normal paleofaults; (v) to highlight the trace of a major Jurassic normal fault, that should have marked an abrupt thinning of the paleomargin; it corresponds now to the contact between the Faisceau Vermiculaire (and associated Série Rousse) and the Siviez-Mischabel basement in the hinge of the Mischabel backfold. We propose a new tectonic scheme for the structure of the Faisceau Vermiculaire and adjacent units involving an early northward folding of the Faisceau Vermiculaire with the Série Rousse and the ophiolitic Schistes Lustrés of the Tsaté nappe, followed by major backfolding responsible for the southward emplacement of these units above the HP Zermatt-Saas and Monte Rosa nappes. Our study at regional scale shows that the group formed by the Alphubel basement, the Faisceau Vermiculaire and the Série Rousse share a tectonic position and stratigraphic sequences identical to those of the Mont Fort nappe, which outcrops on the other side of the Dent Blanche klippe. It leads to the proposition that this group constitutes the eastern extension of the Mont Fort nappe.","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":"84 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141258563","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 : 2024-05-07DOI: 10.1186/s00015-024-00458-3
Romana Boiger, Sergey V. Churakov, Ignacio Ballester Llagaria, Georg Kosakowski, Raphael Wüst, Nikolaos I. Prasianakis
Deep subsurface exploration is important for mining, oil and gas industries, as well as in the assessment of geological units for the disposal of chemical or nuclear waste, or the viability of geothermal energy systems. Typically, detailed examinations of subsurface formations or units are performed on cuttings or core materials extracted during drilling campaigns, as well as on geophysical borehole data, which provide detailed information about the petrophysical properties of the rocks. Depending on the volume of rock samples and the analytical program, the laboratory analysis and diagnostics can be very time-consuming. This study investigates the potential of utilizing machine learning, specifically convolutional neural networks (CNN), to assess the lithology and mineral content solely from analysis of drill core images, aiming to support and expedite the subsurface geological exploration. The paper outlines a comprehensive methodology, encompassing data preprocessing, machine learning methods, and transfer learning techniques. The outcome reveals a remarkable 96.7% accuracy in the classification of drill core segments into distinct formation classes. Furthermore, a CNN model was trained for the evaluation of mineral content using a learning data set from multidimensional log analysis data (silicate, total clay, carbonate). When benchmarked against laboratory XRD measurements on samples from the cores, both the advanced multidimensional log analysis model and the neural network approach developed here provide equally good performance. This work demonstrates that deep learning and particularly transfer learning can support extracting petrophysical properties, including mineral content and formation classification, from drill core images, thus offering a road map for enhancing model performance and data set quality in image-based analysis of drill cores.
{"title":"Direct mineral content prediction from drill core images via transfer learning","authors":"Romana Boiger, Sergey V. Churakov, Ignacio Ballester Llagaria, Georg Kosakowski, Raphael Wüst, Nikolaos I. Prasianakis","doi":"10.1186/s00015-024-00458-3","DOIUrl":"https://doi.org/10.1186/s00015-024-00458-3","url":null,"abstract":"Deep subsurface exploration is important for mining, oil and gas industries, as well as in the assessment of geological units for the disposal of chemical or nuclear waste, or the viability of geothermal energy systems. Typically, detailed examinations of subsurface formations or units are performed on cuttings or core materials extracted during drilling campaigns, as well as on geophysical borehole data, which provide detailed information about the petrophysical properties of the rocks. Depending on the volume of rock samples and the analytical program, the laboratory analysis and diagnostics can be very time-consuming. This study investigates the potential of utilizing machine learning, specifically convolutional neural networks (CNN), to assess the lithology and mineral content solely from analysis of drill core images, aiming to support and expedite the subsurface geological exploration. The paper outlines a comprehensive methodology, encompassing data preprocessing, machine learning methods, and transfer learning techniques. The outcome reveals a remarkable 96.7% accuracy in the classification of drill core segments into distinct formation classes. Furthermore, a CNN model was trained for the evaluation of mineral content using a learning data set from multidimensional log analysis data (silicate, total clay, carbonate). When benchmarked against laboratory XRD measurements on samples from the cores, both the advanced multidimensional log analysis model and the neural network approach developed here provide equally good performance. This work demonstrates that deep learning and particularly transfer learning can support extracting petrophysical properties, including mineral content and formation classification, from drill core images, thus offering a road map for enhancing model performance and data set quality in image-based analysis of drill cores.","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":"67 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140888225","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 : 2024-04-04DOI: 10.1186/s00015-024-00453-8
Duje Smirčić, Matija Vukovski, Damir Slovenec, Duje Kukoč, Branimir Šegvić, Marija Horvat, Mirko Belak, Tonći Grgasović, Luka Badurina
During the Middle Triassic, intensive volcanic activity took place along the eastern margin of Pangea, including the Greater Adria promontory, due to the Neotethyan oceanization. This resulted in the formation of various volcanic and volcaniclastic rock types. The region of NW Croatia, acting as a transition zone between the Southern Alps and the Dinarides, showcases the outcrops of these rocks. The present study investigates the facies of volcaniclastic rocks, the distribution of those facies, formation processes, as well as the genesis of the primary magma to gain a better understanding of the complex geodynamics of this region during the Middle Triassic. Six profiles across the Vudelja quarry front were surveyed using drone imaging and samples were collected for detailed petrographic and geochemical analyses. Two groups of volcaniclastic rocks were identified—mafic and intermediate/felsic. The former is represented by (I) autoclastic effusive facies and (II) resedimented autoclastic facies, while the latter is represented by (III) secondary pyroclastic facies. Mafic volcaniclastics were generated through basaltic effusions in marine environments, fragmentation in contact with seawater, mixing with shallow marine carbonate clasts, and subsequent redeposition in deeper marine areas. The secondary pyroclastic facies (III) consists of a regionally distributed felsic Pietra Verde tuff whose deposits may be related to pyroclastic density currents and syn-eruptive resedimentation by turbidite-like currents. Geochemical data indicate that parental magmas responsible for generating the mafic volcaniclastics had a calc-alkaline composition and originated in ensialic and mature arc settings of an active continental margin. The observed chemical composition is likely inherited from older, arc-related lithologies, associated with the subduction of the Paleotethys Ocean. Parental magmas are thought to have formed during continental rifting of the passive Middle Triassic margins of the Greater Adria through (i) partial melting of the heterogeneous lithospheric mantle, which had been metasomatized during an earlier Hercynian subduction, and (ii) subordinate processes related to the melting of the upper continental crust and subsequent fractionation. Ar/Ar dating on plagioclase separates yielded an age of 244.5 ± 2.8 Ma for mafic volcaniclastics. This aligns well with biostratigraphic ages of felsic tuffs which crop out on a broader regional scale of the Dinarides, the Southern Alps, and the Transdanubian Range. The overlapping ages obtained from radiometric dating of mafic volcaniclastics and biostratigraphic ages of the felsic Pietra Verde tuffs strongly suggest that the Greater Adria region experienced concurrent bimodal volcanism during the Middle Triassic.
{"title":"Facies architecture, geochemistry and petrogenesis of Middle Triassic volcaniclastic deposits of Mt. Ivanščica (NW Croatia): evidence of bimodal volcanism in the Alpine-Dinaridic transitional zone","authors":"Duje Smirčić, Matija Vukovski, Damir Slovenec, Duje Kukoč, Branimir Šegvić, Marija Horvat, Mirko Belak, Tonći Grgasović, Luka Badurina","doi":"10.1186/s00015-024-00453-8","DOIUrl":"https://doi.org/10.1186/s00015-024-00453-8","url":null,"abstract":"During the Middle Triassic, intensive volcanic activity took place along the eastern margin of Pangea, including the Greater Adria promontory, due to the Neotethyan oceanization. This resulted in the formation of various volcanic and volcaniclastic rock types. The region of NW Croatia, acting as a transition zone between the Southern Alps and the Dinarides, showcases the outcrops of these rocks. The present study investigates the facies of volcaniclastic rocks, the distribution of those facies, formation processes, as well as the genesis of the primary magma to gain a better understanding of the complex geodynamics of this region during the Middle Triassic. Six profiles across the Vudelja quarry front were surveyed using drone imaging and samples were collected for detailed petrographic and geochemical analyses. Two groups of volcaniclastic rocks were identified—mafic and intermediate/felsic. The former is represented by (I) autoclastic effusive facies and (II) resedimented autoclastic facies, while the latter is represented by (III) secondary pyroclastic facies. Mafic volcaniclastics were generated through basaltic effusions in marine environments, fragmentation in contact with seawater, mixing with shallow marine carbonate clasts, and subsequent redeposition in deeper marine areas. The secondary pyroclastic facies (III) consists of a regionally distributed felsic Pietra Verde tuff whose deposits may be related to pyroclastic density currents and syn-eruptive resedimentation by turbidite-like currents. Geochemical data indicate that parental magmas responsible for generating the mafic volcaniclastics had a calc-alkaline composition and originated in ensialic and mature arc settings of an active continental margin. The observed chemical composition is likely inherited from older, arc-related lithologies, associated with the subduction of the Paleotethys Ocean. Parental magmas are thought to have formed during continental rifting of the passive Middle Triassic margins of the Greater Adria through (i) partial melting of the heterogeneous lithospheric mantle, which had been metasomatized during an earlier Hercynian subduction, and (ii) subordinate processes related to the melting of the upper continental crust and subsequent fractionation. Ar/Ar dating on plagioclase separates yielded an age of 244.5 ± 2.8 Ma for mafic volcaniclastics. This aligns well with biostratigraphic ages of felsic tuffs which crop out on a broader regional scale of the Dinarides, the Southern Alps, and the Transdanubian Range. The overlapping ages obtained from radiometric dating of mafic volcaniclastics and biostratigraphic ages of the felsic Pietra Verde tuffs strongly suggest that the Greater Adria region experienced concurrent bimodal volcanism during the Middle Triassic.","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":"9 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140584149","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 : 2024-03-26DOI: 10.1186/s00015-024-00454-7
Wilfried Winkler
During the re-mapping of the area for the Geological Atlas of Switzerland, a significant stratigraphic unconformity was discovered in the North Penninic (Valais) Bündnerschiefer and the Flysch series of the northern Prättigau. It separates different units of the Cretaceous Bündnerschiefer from the Palaeogene Flysch. We explain this observation by a basin conversion from extension to compression, which caused the initial deformation of the Bündnerschiefer in an accretionary wedge. Interlinked return-flow has created a new heterogeneous substrate for the flysch sediments and explains the different types of unconformities. The basin conversion coincided with high-grade metamorphism in the vicinity of the the South Penninic suture and the Austroalpine units, and the increased exhumation in the Austroalpine nappe stack. Detrital zircon dating confirms also a change from European to Austroalpine detrital sources in the flysch sandstones. We discuss a palaeotectonic model leading to hP/lT metamorphism of the Bündnerschiefer in the Late Eocene (c. 42 Ma). It appears that the flysch formations were also involved, but to a lesser degree by tectonic deformation from the late Early Eocene onwards, as the pervasive folding characteristic of the Bündnerschiefer is absent. This has been followed by a phase of S-directed backfolding. During the Oligocene and Miocene, more extensive deformation occurred by SE to NW compression and finally by probable westward thrusting and folding. Our main theme is the transition from passive to active continental margins, which in Alpine plate tectonic framework corresponds to the transition to flysch sedimentation by basin conversion. Our results show that the simultaneity of the transition from extension to compression, as indicated by the accumulation of flysch, shifted in time from south to north in the Alpine Tethys.
在为《瑞士地质地图集》（Geological Atlas of Switzerland）重新绘制该地区地图的过程中，发现了北宾夕法尼亚州（瓦莱州）Bündnerschiefer地层和普莱蒂高北部Flysch地层中的一个重要地层不整合现象。它将白垩纪 Bündnerschiefer 和古近纪 Flysch 的不同单元分开。我们对这一现象的解释是，盆地从延伸转变为压缩，导致了增生楔中 Bündnerschiefer 的初始变形。相互连接的回流为 Flysch 沉积物创造了一个新的异质基底，并解释了不同类型的不整合。盆地转换与南宾夕法尼亚缝合线和奥斯特罗派单元附近的高级变质作用以及奥斯特罗派山系堆积层的隆升相吻合。碎屑锆石年代测定也证实了飞沙砂岩中的碎屑来源已从欧洲转变为奥斯特派。我们讨论了一个古构造模型，该模型导致了晚始新世（约 42 Ma）布恩德施费尔地区的 hP/lT 变质作用。从早始新世晚期开始，flysch地层似乎也受到了构造变形的影响，但程度较轻，因为Bündnerschiefer地层不存在普遍的褶皱特征。随后是 S 向反褶阶段。在渐新世和中新世期间，由于从东南到西北的压缩，发生了更广泛的变形，最后可能是向西的推覆和褶皱。我们的主题是从被动大陆边缘向主动大陆边缘的过渡，在阿尔卑斯板块构造框架中，这相当于通过盆地转换向飞沙沉积的过渡。我们的研究结果表明，在阿尔卑斯特提斯地区，从延伸到压缩的过渡（如蝇蛆沉积所示）在时间上从南向北转移。
{"title":"The North Penninic Bündnerschiefer and Flysch of the Prättigau (Swiss Alps) revisited","authors":"Wilfried Winkler","doi":"10.1186/s00015-024-00454-7","DOIUrl":"https://doi.org/10.1186/s00015-024-00454-7","url":null,"abstract":"During the re-mapping of the area for the Geological Atlas of Switzerland, a significant stratigraphic unconformity was discovered in the North Penninic (Valais) Bündnerschiefer and the Flysch series of the northern Prättigau. It separates different units of the Cretaceous Bündnerschiefer from the Palaeogene Flysch. We explain this observation by a basin conversion from extension to compression, which caused the initial deformation of the Bündnerschiefer in an accretionary wedge. Interlinked return-flow has created a new heterogeneous substrate for the flysch sediments and explains the different types of unconformities. The basin conversion coincided with high-grade metamorphism in the vicinity of the the South Penninic suture and the Austroalpine units, and the increased exhumation in the Austroalpine nappe stack. Detrital zircon dating confirms also a change from European to Austroalpine detrital sources in the flysch sandstones. We discuss a palaeotectonic model leading to hP/lT metamorphism of the Bündnerschiefer in the Late Eocene (c. 42 Ma). It appears that the flysch formations were also involved, but to a lesser degree by tectonic deformation from the late Early Eocene onwards, as the pervasive folding characteristic of the Bündnerschiefer is absent. This has been followed by a phase of S-directed backfolding. During the Oligocene and Miocene, more extensive deformation occurred by SE to NW compression and finally by probable westward thrusting and folding. Our main theme is the transition from passive to active continental margins, which in Alpine plate tectonic framework corresponds to the transition to flysch sedimentation by basin conversion. Our results show that the simultaneity of the transition from extension to compression, as indicated by the accumulation of flysch, shifted in time from south to north in the Alpine Tethys.","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":"32 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140299254","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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