Bi-modal deformation styles in confined mass-transport deposits: examples from a salt minibasin in SE Brazil

Gamboa, Davide; Alves, Tiago M.. 2016 Bi-modal deformation styles in confined mass-transport deposits: examples from a salt minibasin in SE Brazil. Marine Geology, 379. 176-193. 10.1016/j.margeo.2016.06.003

Before downloading, please read NORA policies.

[thumbnail of DGamboa_MTDdeformStyles.pdf]

Preview

Text
DGamboa_MTDdeformStyles.pdf - Accepted Version
Download (8MB) | Preview

Official URL: http://dx.doi.org/10.1016/j.margeo.2016.06.003

Abstract/Summary

High-quality 3D seismic data reveal bi-modal deformation styles in mass-transport deposits filling a salt minibasin in SE Brazil (Espírito Santo Basin). We analyse three mass-transport deposits within the same Miocene stratigraphic interval, and four others in Holocene strata. Our interpretation reveals that deformation in the mass-transport deposits relates to their long-axis orientation. As a result, they are divided into two types: a) Type 1 have long axes parallel to the direction of movement and show significant internal deformation; b) Type 2 have long axes perpendicular to the direction of movement, are highly heterogeneous and include large undeformed slabs. The long axes of Type 2 mass-transport deposits are parallel to the strike of bounding faults and salt structures. The majority of mass-transport deposits show intense deformation at their headwalls, and relative short remobilisation distances are inferred for both Types 1 and 2. In the study area, the timing of emplacement of mass-transport deposits was controlled by the growth of adjacent salt ridges. Earlier halokinesis in the northern axial areas of the minibasin shifted southwards in a second stage. Holocene mass-transport deposits suggest alternating growth of the eastern and western salt ridges. Our results show that detailed seismic-stratigraphic analyses are a key to understanding the timings and magnitude of deformation of mass-transport deposits in salt minibasins. The classification proposed can be applied to MTDs on continental margins and in lacustrine settings.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.margeo.2016.06.003
ISSN:	00253227
Date made live:	12 Dec 2016 14:08 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/515474

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.margeo.2016.06.003

ISSN:

00253227

Date made live:

12 Dec 2016 14:08 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/515474