14 documents found, page 1 of 2
Multidisciplinary characterization of Quaternary mass movement deposits in the ...
Silva, P. F.; Roque, C.; Drago, T.; Belen, A.; Henry, B.; Gemma, E.; Lopes, Ana; Lopez-Gonzalez, N.; Casas, D.; Naughton, F.; Naughton, F.We present a multidisciplinary study of the seismic stratigraphy, sedimentology, geochemistry and magnetism to characterize the Quaternary mass movement deposits (MMD) and the associated deformation in the Portimao Bank (Gulf of Cadiz, offshore SW Iberia). Two scales of approach have been applied. At large-scale (m to km) approach, were recognized and characterized a series of important and subsequent slide sca...
Multidisciplinary characterization of Quaternary mass movement deposits in the ...
Silva, Pedro; Roque, C.; Drago, Teresa; Belen, A.; Ercilla, Gemma; Lopes, Ana; Lopez-Gonzalez, Nieves; CASAS, DAVID; Naughton, F.; Vazquez, Juan-TomasWe present a multidisciplinary study of the seismic stratigraphy, sedimentology, geochemistry and magnetism to characterize the Quaternary mass movement deposits (MMD) and the associated deformation in the Portimão Bank (Gulf of Cadiz, offshore SW Iberia). Two scales of approach have been applied. At large-scale (m to km) approach, were recognized and characterized a series of important and subsequent slide sca...
Evidence for non-coaxiality of ferrimagnetic and paramagnetic fabrics, develope...
Silva, Pedro Manuel de Almeida Carvalho da; Marques, Fernando O.; Machek, M.; Henry, B.; Hirt, A. M.; Roxerova, Z.; Madureira, P.; Vratislav, S.A detailed analysis of fabrics of the chilled margin of a thick dolerite dyke (Foum Zguid dyke, Southern Morocco) was performed in order to better understand the development of sub-fabrics during dyke emplacement and cooling. AMS data were complemented with measurements of paramagnetic and ferrimagnetic fabrics (measured with high field torque magnetometer), neutron texture and microstructural analyses. The fer...
Intrusion of Lamprophyre dyke and related deformation effects in the host rock ...
Machek, M.; Roxerova, Z.; Zavada, P.; Silva, Pedro Manuel Fernandes Carvalho da; Henry, B.; Dedecek, P.; Petrovsky, E.; Marques, Fernando O.A rock salt-lamprophyre dyke contact zone (sub-vertical, NE-SW strike) was investigated for its petrographic, mechanic and physical properties by means of anisotropy of magnetic susceptibility CAMS) and rock magnetic properties, coupled with quantitative microstructural analysis and thermal mathematical modelling. The quantitative microstructural analysis of halite texture and solid inclusions revealed good spa...
Palaeomagnetism in the Sines massif (SW Iberia) revisited: evidences for Late C...
Ribeiro, P.; Silva, P. F.; Moita, P.; Kratinova, Z.; Marques, F. O.; Henry, B.
Palaeomagnetic study of a subaerial volcanic ridge (Sao Jorge Island, Azores) f...
Silva, Pedro; Henry, B.; Marques, Fernando O.; Hildenbrand, A.; Madureira, P.; Meriaux, C. A.; Kratinova, Z.We present a palaeomagnetic study on 38 lava flows and 20 dykes encompassing the past 1.3 Myr on S. Jorge Island (Azores ArchipelagoNorth Atlantic Ocean). The sections sampled in the southeastern and central/western parts of the island record reversed and normal polarities, respectively. They indicate a mean palaeomagnetic pole (81.3 degrees N, 160.7 degrees E, K= 33 and A95= 3.4 degrees) with a latitude shallo...
Palaeomagnetic study of a subaerial volcanic ridge (São Jorge Island, Azores) f...
Silva, P. F.; Henry, B.; Marques, Fernando O.; Hildenbrand, A.; Madureira, P.; Meriaux, C. A.; Kratinova, Z.We present a palaeomagnetic study on 38 lava flows and 20 dykes encompassing the past 1.3 Myr on S. Jorge Island (Azores ArchipelagoNorth Atlantic Ocean). The sections sampled in the southeastern and central/western parts of the island record reversed and normal polarities, respectively. They indicate a mean palaeomagnetic pole (81.3 degrees N, 160.7 degrees E, K= 33 and A95= 3.4 degrees) with a latitude shallo...
Reconstructing the architectural evolution of volcanic islands from combined K/...
Hildenbrand, A.; Marques, Fernando O.; Costa, A. C. G.; Sibrant, A. L. R.; Silva, Pedro; Henry, B.; MIRANDA, JORGE MIGUEL; Madureira, P.The morpho-structural evolution of oceanic islands results from competition between volcano growth and partial destruction by mass-wasting processes. We present here a multi-disciplinary study of the successive stages of development of Faial (Azores) during the last 1 Myr. Using high-resolution digital elevation model (DEM), and new K/Ar, tectonic, and magnetic data, we reconstruct the rapidly evolving topograp...
Paleomagnetic study of the Great Foum Zguid dyke (southern Morocco): A positive...
Silva, Pedro; Henry, B.; Marques, Fernando O.; Madureira, P.; Miranda, Jorge MiguelWhen a paleomagnetic pole is sought for in an igneous body, the host rocks should be subjected to a contact test to assure that the determined paleopole has the age of the intrusion. If the contact test is positive, it precludes the possibility that the measured magnetization is a later effect. Therefore, we investigated the variations of the remanent magnetization along cross-sections of rocks hosting the Foum...
Variation of magnetic properties in sedimentary rocks hosting the Foum Zguid dy...
Silva, Pedro; Henry, B.; Marques, Fernando O.; Mateus, A.; Madureira, P.; Lourenço, N.; Miranda, Jorge MiguelThe effects of dyke intrusion on the magnetic properties of host sedimentary rocks are still poorly understood. Therefore, we have evaluated bulk magnetic parameters of standard palaeomagnetic samples collected along several sections across the sediments hosting the Foum Zguid dyke in southern Morocco. The study has been completed with the evaluation of the magnetic fabric after laboratory application of sequen...