C.G. Kingsbury, W. Altermann, J. Kramers, R.E. Ernst, U. Söderlund, M. Klausen
{"title":"南非大塞德伯格-法尔兹湾大型火成岩省:与南大西洋断裂有关的广泛岩浆活动的南部节点","authors":"C.G. Kingsbury, W. Altermann, J. Kramers, R.E. Ernst, U. Söderlund, M. Klausen","doi":"10.25131/sajg.126.0023","DOIUrl":null,"url":null,"abstract":"\n A new 130 to 140 Ma mafic dyke swarm, is identified in western South Africa. It consists of the previously undated Cederberg dyke swarm (CDS), for which we report U-Pb ID-TIMS baddeleyite ages of 131.4 ± 4.5 Ma (Knersvlake subswarm) and 133.0 ± 1.5 Ma (Doring-Tanqua subswarm). 40Ar/39Ar dates on these two samples and two additional dates of the Doring – Tanqua subswarm cluster between 128.5 ± 1.4 Ma and 132.2 ± 1.5 Ma. We also report 40Ar/39Ar ages of 139.3 ± 3.5 Ma for an east-west trending dyke located further north: 27 km south of Kleinsee, and 140.3 ± 1.2 Ma for an east-west dyke near Garies. Together, these eight ages robustly date the emplacement of the northern part of a Greater Cederberg-False Bay Dyke Swarm (GCFDS) at ca. 130 to 140 Ma. Trace and rare earth element datareported herein suggest these dykes are compositionally E-MORB basalts that underwent modification either via subduction-modified lithospheric mantle, or by continental crust, or a combination thereof, and are petrogenetically similar to the ca. 132 Ma False Bay dykes around Cape Town. Therefore, we propose to unify all these coeval and compositionally similar dykes into one large igneous province (LIP) termed the Greater Cederberg-False Bay Large Igneous Province (GCF-LIP).","PeriodicalId":49494,"journal":{"name":"South African Journal of Geology","volume":"60 20","pages":""},"PeriodicalIF":1.2000,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The Greater Cederberg–False Bay Large Igneous Province in South Africa: A southern node of widespread magmatism associated with South Atlantic rifting\",\"authors\":\"C.G. Kingsbury, W. Altermann, J. Kramers, R.E. Ernst, U. Söderlund, M. Klausen\",\"doi\":\"10.25131/sajg.126.0023\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"\\n A new 130 to 140 Ma mafic dyke swarm, is identified in western South Africa. It consists of the previously undated Cederberg dyke swarm (CDS), for which we report U-Pb ID-TIMS baddeleyite ages of 131.4 ± 4.5 Ma (Knersvlake subswarm) and 133.0 ± 1.5 Ma (Doring-Tanqua subswarm). 40Ar/39Ar dates on these two samples and two additional dates of the Doring – Tanqua subswarm cluster between 128.5 ± 1.4 Ma and 132.2 ± 1.5 Ma. We also report 40Ar/39Ar ages of 139.3 ± 3.5 Ma for an east-west trending dyke located further north: 27 km south of Kleinsee, and 140.3 ± 1.2 Ma for an east-west dyke near Garies. Together, these eight ages robustly date the emplacement of the northern part of a Greater Cederberg-False Bay Dyke Swarm (GCFDS) at ca. 130 to 140 Ma. Trace and rare earth element datareported herein suggest these dykes are compositionally E-MORB basalts that underwent modification either via subduction-modified lithospheric mantle, or by continental crust, or a combination thereof, and are petrogenetically similar to the ca. 132 Ma False Bay dykes around Cape Town. Therefore, we propose to unify all these coeval and compositionally similar dykes into one large igneous province (LIP) termed the Greater Cederberg-False Bay Large Igneous Province (GCF-LIP).\",\"PeriodicalId\":49494,\"journal\":{\"name\":\"South African Journal of Geology\",\"volume\":\"60 20\",\"pages\":\"\"},\"PeriodicalIF\":1.2000,\"publicationDate\":\"2023-12-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"South African Journal of Geology\",\"FirstCategoryId\":\"93\",\"ListUrlMain\":\"https://doi.org/10.25131/sajg.126.0023\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"South African Journal of Geology","FirstCategoryId":"93","ListUrlMain":"https://doi.org/10.25131/sajg.126.0023","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOLOGY","Score":null,"Total":0}
The Greater Cederberg–False Bay Large Igneous Province in South Africa: A southern node of widespread magmatism associated with South Atlantic rifting
A new 130 to 140 Ma mafic dyke swarm, is identified in western South Africa. It consists of the previously undated Cederberg dyke swarm (CDS), for which we report U-Pb ID-TIMS baddeleyite ages of 131.4 ± 4.5 Ma (Knersvlake subswarm) and 133.0 ± 1.5 Ma (Doring-Tanqua subswarm). 40Ar/39Ar dates on these two samples and two additional dates of the Doring – Tanqua subswarm cluster between 128.5 ± 1.4 Ma and 132.2 ± 1.5 Ma. We also report 40Ar/39Ar ages of 139.3 ± 3.5 Ma for an east-west trending dyke located further north: 27 km south of Kleinsee, and 140.3 ± 1.2 Ma for an east-west dyke near Garies. Together, these eight ages robustly date the emplacement of the northern part of a Greater Cederberg-False Bay Dyke Swarm (GCFDS) at ca. 130 to 140 Ma. Trace and rare earth element datareported herein suggest these dykes are compositionally E-MORB basalts that underwent modification either via subduction-modified lithospheric mantle, or by continental crust, or a combination thereof, and are petrogenetically similar to the ca. 132 Ma False Bay dykes around Cape Town. Therefore, we propose to unify all these coeval and compositionally similar dykes into one large igneous province (LIP) termed the Greater Cederberg-False Bay Large Igneous Province (GCF-LIP).
期刊介绍:
The South African Journal of Geology publishes scientific papers, notes, stratigraphic descriptions and discussions in the broadly defined fields of geoscience that are related directly or indirectly to the geology of Africa. Contributions relevant to former supercontinental entities such as Gondwana and Rodinia are also welcome as are topical studies on any geoscience-related discipline. Review papers are welcome as long as they represent original, new syntheses. Special issues are also encouraged but terms for these must be negotiated with the Editors.