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|Title: ||Interpretação tectónica de um conjunto de lineamentos WNW-ESE observados em imagens landsat da margem oeste ibérica|
|Authors: ||Kullberg, M. C.|
Kullberg, J. C.
|Issue Date: ||2000|
|Publisher: ||Museu Nacional de História Natural da Universidade de Lisboa|
|Abstract: ||The existence of satellite images ofthe West Iberian Margin allowed comparative study of images
as a tool applied to structural geology. Interpretation of LANDSAT images of the Lusitanian Basin
domain showed the existence of a not previously described WNW-ESE trending set oflineaments.
These lineaments are persistent and only observable on small scale images (e.g. approx. 11200000
and 11500 000) with various radiometric characteristics. They are approximately 20 km long, trend
l200±15° and cross cut any other families oflineaments.
The fact that these lineaments are perpendicular to the Quaternary thrusts of the Lower Tagus
Valley and also because they show no off-set across them, suggests that they resulted from intersection
oflarge tensile fractures on the earth's surface. It is proposed in this work that these lineaments formed
on a crustal flexure of tens ofkm long, associated with the Quaternary WNW-ESE oriented maximum
compressive stress on the West Iberian Margin. The maximum compressive stress rotated anticlockwise
from a NW -SE orientation to approximately WNW-ESE, from Late Miocene to Quaternary
times (RIBEIRO et aI., 1996).
Field inspection of the lineaments revealed zones of norm~1.J. faulting and cataclasis, which are
coincident with the lineaments and affect sediments of upper Miocene up to Quaternary age. These
deformation structures show localized extension perpendicular to the lineaments, i.e. perpendicular to
the maximum compressive direction, after recent stress data along the West Portuguese Margin
(CABRAL & RIBEIRO, 1989; RIBEIRO et at., 1996).
Also, on a first approach, the geographical distribution of these lineaments correlates well with
earthquake epicenters and areas of largest Quaternary Vertical Movements within the inverted
Lusitanian Basin (CABRAL, 1995).|
|Appears in Collections:||FCT: DCT - Artigos em revista nacional com arbitragem científica|
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