H. E. Hachimi, N. Youbi, J. Madeira, A. Marzoli, J. Mata, H. Bertrand, M. K. Bensalah, Moulay Ahmed Boumehdi, M. Doblas, F. Medina, M. Abbou, L. Martins
{"title":"摩洛哥中部高阿特拉斯中大西洋岩浆省(CAMP)熔岩流的物理火山学和侵位机制","authors":"H. E. Hachimi, N. Youbi, J. Madeira, A. Marzoli, J. Mata, H. Bertrand, M. K. Bensalah, Moulay Ahmed Boumehdi, M. Doblas, F. Medina, M. Abbou, L. Martins","doi":"10.5802/crgeos.7","DOIUrl":null,"url":null,"abstract":"The best preserved and most complete lava flow sequences of the Central Atlantic Magmatic Province (CAMP) in Morocco are exposed in the Central High Atlas and can reach up to 300 m in thickness. Four distinct formations, emplaced in subaerial environments, are classically recognized: the ∗Corresponding author. ISSN (electronic) : 1778-7025 https://comptes-rendus.academie-sciences.fr/geoscience/ 456 Hind El Hachimi et al. Lower, Intermediate, Upper and Recurrent formations. These formations are separated by paleosoils and sedimentary sequences (mudstones, siltstones, sandstones, limestones), that are in general less than two meter-thick and may exceptionally reach a thickness of 80 m, representing minor periods of volcanic quiescence. CAMP lava flows of the Central High Atlas can be grouped into two main categories: subaerial compound pahoehoe flows and simple flows. The former type is exclusively confined to the Lower and Intermediate Formations, while simple flows occur in the Upper and Recurrent Formations. The dominance of compound flows in the two lowermost units of the CAMP suggests a slow emplacement during successive sustained eruptive episodes. Instead the thick single flows characterizing the Upper and Recurrent units indicate higher effusive rates. Basaltic pillow lavas (always of short lateral extent: 10 to 100 m), showing radial jointing and vitreous rinds, identical to those found in the Western Meseta, are occasionally associated with hyaloclastites in the base of the Intermediate Formation, immediately above clastic sediments, or in the Upper Formation. The occurrence of pillow lavas does not imply a generalized subaqueous environment at the time of the lava emission. Instead, they represent subaerial flows that entered small lakes occupying depressions on the volcanic topography of the Lower and Intermediate Formations. The short lateral extent of the pillow lavas and their constant stratigraphic position, the existence of lava flows with unequivocal subaerial characteristics associated to sediments containing fossilized wood, clearly indicate onshore emplacement.","PeriodicalId":50651,"journal":{"name":"Comptes Rendus Geoscience","volume":null,"pages":null},"PeriodicalIF":2.0000,"publicationDate":"2020-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":"{\"title\":\"Physical volcanology and emplacement mechanism of the Central Atlantic Magmatic Province (CAMP) lava flows from the Central High Atlas, Morocco\",\"authors\":\"H. E. Hachimi, N. Youbi, J. Madeira, A. Marzoli, J. Mata, H. Bertrand, M. K. Bensalah, Moulay Ahmed Boumehdi, M. Doblas, F. Medina, M. Abbou, L. Martins\",\"doi\":\"10.5802/crgeos.7\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The best preserved and most complete lava flow sequences of the Central Atlantic Magmatic Province (CAMP) in Morocco are exposed in the Central High Atlas and can reach up to 300 m in thickness. Four distinct formations, emplaced in subaerial environments, are classically recognized: the ∗Corresponding author. ISSN (electronic) : 1778-7025 https://comptes-rendus.academie-sciences.fr/geoscience/ 456 Hind El Hachimi et al. Lower, Intermediate, Upper and Recurrent formations. These formations are separated by paleosoils and sedimentary sequences (mudstones, siltstones, sandstones, limestones), that are in general less than two meter-thick and may exceptionally reach a thickness of 80 m, representing minor periods of volcanic quiescence. CAMP lava flows of the Central High Atlas can be grouped into two main categories: subaerial compound pahoehoe flows and simple flows. The former type is exclusively confined to the Lower and Intermediate Formations, while simple flows occur in the Upper and Recurrent Formations. The dominance of compound flows in the two lowermost units of the CAMP suggests a slow emplacement during successive sustained eruptive episodes. Instead the thick single flows characterizing the Upper and Recurrent units indicate higher effusive rates. Basaltic pillow lavas (always of short lateral extent: 10 to 100 m), showing radial jointing and vitreous rinds, identical to those found in the Western Meseta, are occasionally associated with hyaloclastites in the base of the Intermediate Formation, immediately above clastic sediments, or in the Upper Formation. The occurrence of pillow lavas does not imply a generalized subaqueous environment at the time of the lava emission. Instead, they represent subaerial flows that entered small lakes occupying depressions on the volcanic topography of the Lower and Intermediate Formations. The short lateral extent of the pillow lavas and their constant stratigraphic position, the existence of lava flows with unequivocal subaerial characteristics associated to sediments containing fossilized wood, clearly indicate onshore emplacement.\",\"PeriodicalId\":50651,\"journal\":{\"name\":\"Comptes Rendus Geoscience\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.0000,\"publicationDate\":\"2020-07-15\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"2\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Comptes Rendus Geoscience\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.5802/crgeos.7\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Comptes Rendus Geoscience","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.5802/crgeos.7","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 2
摘要
摩洛哥中大西洋岩浆省(CAMP)保存最完好、最完整的熔岩流层序暴露在中部高地图集,厚度可达300 m。四种不同的地层,位于地面环境中,被经典地识别:ISSN(电子):1778-7025 https://comptes-rendus.academie-sciences.fr/geoscience/ 456 Hind El Hachimi等。下、中、上、回地层。这些地层被古土壤和沉积层(泥岩、粉砂岩、砂岩、灰岩)隔开,通常厚度不到2米,也有可能达到80米,代表了火山静止的小时期。中央高阿特拉斯的CAMP熔岩流可分为两大类:陆上复合pahoe流和简单流。前一种类型仅局限于下部和中间组,而简单的流动发生在上部和回流组。在CAMP最底部的两个单元中,复合流占主导地位,表明在连续持续的喷发事件中缓慢就位。相反,上单元和回流单元的厚单流表明较高的渗出率。玄武岩枕状熔岩(通常横向范围较短:10 - 100米),呈放射状节理和玻璃状外壳,与在西梅塞塔发现的相同,偶尔与中间组底部、碎屑沉积物上方或上组的透明质碎屑岩相关联。枕状熔岩的出现并不意味着熔岩喷发时是一个普遍的水下环境。相反,它们代表了进入占据下、中地层火山地形洼地的小湖泊的陆上水流。枕状熔岩的横向范围短,地层位置稳定,熔岩流的存在与含有化石木材的沉积物相关联,具有明确的陆上特征,清楚地表明了陆上侵位。
Physical volcanology and emplacement mechanism of the Central Atlantic Magmatic Province (CAMP) lava flows from the Central High Atlas, Morocco
The best preserved and most complete lava flow sequences of the Central Atlantic Magmatic Province (CAMP) in Morocco are exposed in the Central High Atlas and can reach up to 300 m in thickness. Four distinct formations, emplaced in subaerial environments, are classically recognized: the ∗Corresponding author. ISSN (electronic) : 1778-7025 https://comptes-rendus.academie-sciences.fr/geoscience/ 456 Hind El Hachimi et al. Lower, Intermediate, Upper and Recurrent formations. These formations are separated by paleosoils and sedimentary sequences (mudstones, siltstones, sandstones, limestones), that are in general less than two meter-thick and may exceptionally reach a thickness of 80 m, representing minor periods of volcanic quiescence. CAMP lava flows of the Central High Atlas can be grouped into two main categories: subaerial compound pahoehoe flows and simple flows. The former type is exclusively confined to the Lower and Intermediate Formations, while simple flows occur in the Upper and Recurrent Formations. The dominance of compound flows in the two lowermost units of the CAMP suggests a slow emplacement during successive sustained eruptive episodes. Instead the thick single flows characterizing the Upper and Recurrent units indicate higher effusive rates. Basaltic pillow lavas (always of short lateral extent: 10 to 100 m), showing radial jointing and vitreous rinds, identical to those found in the Western Meseta, are occasionally associated with hyaloclastites in the base of the Intermediate Formation, immediately above clastic sediments, or in the Upper Formation. The occurrence of pillow lavas does not imply a generalized subaqueous environment at the time of the lava emission. Instead, they represent subaerial flows that entered small lakes occupying depressions on the volcanic topography of the Lower and Intermediate Formations. The short lateral extent of the pillow lavas and their constant stratigraphic position, the existence of lava flows with unequivocal subaerial characteristics associated to sediments containing fossilized wood, clearly indicate onshore emplacement.
期刊介绍:
Created in 1835 by physicist François Arago, then Permanent Secretary, the journal Comptes Rendus de l''Académie des sciences allows researchers to quickly make their work known to the international scientific community.
It is divided into seven titles covering the range of scientific research fields: Mathematics, Mechanics, Chemistry, Biology, Geoscience, Physics and Palevol. Each series is led by an editor-in-chief assisted by an editorial committee. Submitted articles are reviewed by two scientists with recognized competence in the field concerned. They can be notes, announcing significant new results, as well as review articles, allowing for a fine-tuning, or even proceedings of symposia and other thematic issues, under the direction of invited editors, French or foreign.