Geologia e controle estrutural do enxame de diques Rio Ceará-Mirim na porção Leste do Rio Grande do Norte
The Rio Ceará-Mirim Dikes Swarm (EDCM) is composed of E-W oriented tabular bodies of basalts/diabases, mainly exposed in Rio Grande do Norte, Brazil. The EDCM extends to southern Ceará showing progressively less frequent occurrences. The western termination of EDCM follows the NE-SW Cariri-Potigu...
Na minha lista:
| Autor principal: | |
|---|---|
| Outros Autores: | |
| Formato: | bachelorThesis |
| Idioma: | pt_BR |
| Publicado em: |
Universidade Federal do Rio Grande do Norte
|
| Assuntos: | |
| Endereço do item: | https://repositorio.ufrn.br/handle/123456789/34384 |
| Tags: |
Adicionar Tag
Sem tags, seja o primeiro a adicionar uma tag!
|
| Resumo: | The Rio Ceará-Mirim Dikes Swarm (EDCM) is composed of E-W oriented
tabular bodies of basalts/diabases, mainly exposed in Rio Grande do Norte, Brazil.
The EDCM extends to southern Ceará showing progressively less frequent
occurrences. The western termination of EDCM follows the NE-SW Cariri-Potiguar
trend, which control some sedimentary basins. Expressive rifting systems involving
South America and Africa is responsible for generation of the EDCM during Lower
Cretaceous. The present paper aims a better comprehension of the structural control
related to accommodation and propagation of EDCM. The methodology comprised
remote sensors image analysis, visits to outcrops and microscopic description. It is
possible to divide the dikes sampled into two groups according to mineralogical and
petrographic characteristics. The first comprises diabases and basalts containing
augite, plagioclase, crypto / microcrystalline groundmass, opaque, apatite and
vesicular zeolite. The second group has olivine, titanoaugite, plagioclase, biotite,
opaque and apatite as mineral assemblage. Integrated analysis of maximum
distension plane associated to the dikes indicates crustal distension approximately NS with slight transcurrent dextral component (sigma3 = 005 Az). Crosscutting
relationships show three magmatic pulses with the E-W dikes as the first one, later
affected by NE-SW dike of second pulse. Finally, a third pulse cuts with WNW-ESE
direction the previous structures. This relationship is related to NW-SE alignment of
distension axis in Rio Salgado River dikes (Lajes/RN), according to Potiguar Rift
orientation. Morphological features suggest a predominant crustal stretching for dikes
accommodation and propagation. However, some structures denote a participative
hydraulic fracturing. |
|---|