The Cretaceous Alkaline Dyke Swarm in the Central Segment of the Asunción Rift, Eastern Paraguay : Its Regional Distribution, Mechanism of Emplacement, and Tectonic Significance
Joint Authors
Velázquez, Victor F.
Gomes, Celso de Barros
Kirk, Jason
Riccomini, Claudio
Source
Journal of Geological Research
Issue
Vol. 2011, Issue 2011 (31 Dec. 2011), pp.1-18, 18 p.
Publisher
Hindawi Publishing Corporation
Publication Date
2011-04-27
Country of Publication
Egypt
No. of Pages
18
Main Subjects
Earth Science , Water and Environment
Abstract EN
A structural analysis of Cretaceous alkaline dykes swarm associated with the central segment of the Asunción Rift is reported here.
Dykes are generally single near-vertical tabular bodies, less than 5 m wide, although multiple and composite intrusions also occur.
Many of these small bodies have been emplaced into Paleozoic sedimentary rocks and exhibit a regional NW-SE orientation pattern.
Petrographical and geochemical data allow recognition of two different lineages of potassic dykes: a silica-undersaturated suite ranging from basanite to phonolite (B-P) and a silica-saturated suite ranging from alkali basalt to trachyte (AB-T).
The morphological features, the regional en-échelon distribution, and the NW-SE orientation pattern suggest that the dykes were injected along fractures and faults, under a transtensional tectonic regime with σ1 NW/horizontal, σ2/vertical, and σ3 NE/horizontal.
Detailed analysis, combining dyke petrography, orientation pattern, and relative chronology reveals a rotation from WNW toward NNW during dyke emplacement.
In terms of the paleostress field orientation, the evidence indicates that the dykes were diachronically formed under a similar stress condition.
Finally, the pattern of orientation documented for the Cretaceous alkaline dykes of the Asunción Rift is consistent, temporally and spatially, with the phases of regional deformation that occurred during the process of the Atlantic Ocean opening.
American Psychological Association (APA)
Velázquez, Victor F.& Riccomini, Claudio& Gomes, Celso de Barros& Kirk, Jason. 2011. The Cretaceous Alkaline Dyke Swarm in the Central Segment of the Asunción Rift, Eastern Paraguay : Its Regional Distribution, Mechanism of Emplacement, and Tectonic Significance. Journal of Geological Research،Vol. 2011, no. 2011, pp.1-18.
https://search.emarefa.net/detail/BIM-510405
Modern Language Association (MLA)
Velázquez, Victor F.…[et al.]. The Cretaceous Alkaline Dyke Swarm in the Central Segment of the Asunción Rift, Eastern Paraguay : Its Regional Distribution, Mechanism of Emplacement, and Tectonic Significance. Journal of Geological Research No. 2011 (2011), pp.1-18.
https://search.emarefa.net/detail/BIM-510405
American Medical Association (AMA)
Velázquez, Victor F.& Riccomini, Claudio& Gomes, Celso de Barros& Kirk, Jason. The Cretaceous Alkaline Dyke Swarm in the Central Segment of the Asunción Rift, Eastern Paraguay : Its Regional Distribution, Mechanism of Emplacement, and Tectonic Significance. Journal of Geological Research. 2011. Vol. 2011, no. 2011, pp.1-18.
https://search.emarefa.net/detail/BIM-510405
Data Type
Journal Articles
Language
English
Notes
Includes bibliographical references
Record ID
BIM-510405