http://hdl.handle.net/10362/1448 2013-05-22T05:42:54Z http://hdl.handle.net/10362/3357 Title: Litostratigrafia do Cenozóico de Portuga Authors: Pais, J; Cunha, PP; Legoinha, P Editors: J.M.C., Neiva; A., Ribeiro; L., Mendes Victor; F., Noronha; M., Magalhães Ramalho Abstract: In Portugal mainland the Cenozoic record occurs largely in several basins. Even in the same basin, the sedimentary record shows meaningful lateral facies and thickness changes. However, the main sedimentary ruptures and overall lithologic characteristics of the infillings stades are quite similar in the same basins, as a result of the geodinamic evolution of Iberia and the Cainozoic times eustatic and climate changes. A stratigraphic framework is proposed in order to allow a less complex use of the lithostratigraphic units as referred in the geological maps and literature. Some topics for future research are suggested. 2010-01-01T00:00:00Z http://hdl.handle.net/10362/5427 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. 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). 2000-01-01T00:00:00Z http://hdl.handle.net/10362/5413 Title: Tectónica da cadeia da Arrábida Authors: Kullberg, M. C.; Kullberg, J. C.; Terrinha, P. Abstract: A tectonic map of the Arrábida fold and thrust belt ( 30 km x 6 km) based on aerial-photo interpretation and field work is presented together with geological cross-sections constrained by seismic and gravimetric data, one restored section and kinematic models for the evolution of the Sesimbra salt-wall and the Palmela gravitational slide. Two rifting episodes of Lias-Dogger, and Malm ages, were recognized in the Arrábida rotated fault-block that were accommodated by two normal fault systems striking approximately N-S and E-W. Two episodes of tectonic inversion occurred during Miocene times (Burdigalian and Late Tortonian) during which the N-S faults were reactivated as lateral ramps and the E-W faults as thrusts that formed on a backward propagation sequence. The structure and style of deformation of the Arrábida belt were controlled by the inherited Mesozoic structure and the non-stretched basement that bounds the Arrábida block to the south and east. Although most of the inversion structure appears to be thin-skinned gravimetric modelling (SILVA, 1992) indicates some involvement of the basement in the Viso duplex. The existence of only one detachment, the Hettangian evaporite complex, whose depth to is estimated between 3.5 km and 2.2 km, as constrained by gravimetric and geometric models, is the reason for the simple and elegant geometry of the Arrábida fold and thrust belt. Shortening across the belt was estimated in e = 35% (RAMSAY, 1967) using a 10 km section drawn between Quinta do Anjo (loose line) and Albarquel (pin point) in the eastern sector of the Arrábida belt, across the Serra de São Luís and Viso structures.Apositive strain gradient from north to south and west to east is observed at cartographic scale and was corroborated by independent strain analysis ( P. RIBEIRO, et al., 1996; A. RIBEIRO, et al., 1996) Description: Geociências, Museu Nac. Hist. Nat. Univ. Lisboa, nº 2, 35-84 2000-01-01T00:00:00Z http://hdl.handle.net/10362/5412 Title: Tectónica da região de Sintra Authors: Kullberg, M. C.; Kullberg, J. C. Abstract: Photo-interpretation of aerial stereopairs of the Sintra region on the approx. 1/32 000 scale together with field work allowed the production of the present Tectonic Map of the Sintra region. It is now possible to separate structures which resulted from two different tectonic events: one, corresponding to the intrusion of the Late Cretaceous Sintra igneous diapir, and the other the Miocene compressive event, the most important tectonic inversion phase of the Lusitanian Basin. The former are present to the south, southeast and east of the intrusion and within the intrusion itself, affecting the peripheral granites and their contacts with the gabbro-syenite core. These structures comprehend: i) faults and conical fractures striking parallel to the massif boundary, which were intruded by dykes, ii) vertical faults and fractures of two conjugate sets, dextral NNW-SSE and sinistral NNE-SSW. These faults are certainly associated with the E-W striking massif's northwards directed thrust and indicate a N-S oriented horizontal maximum compressive stress. The Miocene compressive event reactivated most of the inherited structures as follows. The NNWSSE faults located on the Sintra southern platform were reactivated as dextral strike slip faults and the E-W thrust along the northern boundary of the massif was also reactivated. This thrust propagated to the east. It also enhanced the asymmetry of the rim-syncline, uplifted the massif and reactivated the NNE-SSW faults as sinistral lateral ramps, which also accommodated vertical throw. The present Tectonic Map of Sintra together with the available geophysical data (MOREIRA, 1984, KULLBERG et al., 1991, SILVA & MIRANDA, 1994) allowed reassessment of the models proposed for the emplacement of the Sintra, Sines and Monchique igneous massifs, which intruded during Late Cretaceous times along the deep dextral NNW-SSE oriented strike slip fault (RIBEIRO et al., 1979; TERRINHA, 1998; TERRINHA & KULLBERG, 1998). 2000-01-01T00:00:00Z