Simultaneous development of semigrabens orthogonal and oblique to the extension direction: physical modeling of natural analogues in Northeastern Brazil
The physical modeling tool is being increasingly used in geology to provide information about the evolutionary stages (nucleation, growth and geometry) of geological structures at various scales. In the simulations of extensional tectonics, modeling provides a better understanding of fault geometr...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Universidade de São Paulo
2014-03-01
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| Series: | Geologia USP. Série Científica |
| Subjects: | |
| Online Access: | http://ppegeo.igc.usp.br/pdf/guspsc/v14n1/a03v14n1.pdf |
| Summary: | The physical modeling tool is being increasingly used in geology to provide information about the evolutionary stages
(nucleation, growth and geometry) of geological structures at various scales. In the simulations of extensional tectonics,
modeling provides a better understanding of fault geometry and evolution of the tectonic-stratigraphic architecture of rift
basins. In this study a sandbox type apparatus was used to study the nucleation and development of basins influenced by
previous structures in the basement, variably oriented as regards to the main extensional axis. Two types of experiments
were conducted in order to: (i) simulate the individual (independent) development of half-grabens oriented orthogonal or
oblique to the extension direction; (ii) simulate the simultaneous development of such half-grabens, orthogonal or oblique
to the extension direction. In both cases the same materials (sand mixed with gypsum) were used and the same boundary
conditions were maintained. The results were compared with a natural analogue represented by the Rio do Peixe Basin
(one of the eocretaceous interior basins of Northeast Brazil). The obtained models allowed to observe the development of
segmented border faults with listric geometry, often forming relay ramps, and the development of inner basins faults that
affect only the basal strata, like the ones observed in the seismic sections of the natural analogue. The results confirm the
importance of basement tectonic heritage in the geometry of rift depocenters. |
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| ISSN: | 1519-874X 1519-874X |