Geogaceta -- Nº 17, (1994)

Permanent URI for this collectionhttps://hdl.handle.net/10272/13751

Browse

Now showing 1 - 20 of 41

Structure, cinématique et chronologie des déformations dans la dorsale du Haouz (Rif, Maroc)
(Sociedad Geológica de España, 1994) Hlila, Rachid; Sanz de Galdeano, Carlos
The complex thrust-slice structure of the Haouz Mountains was formed during the Neogene in several phases, in which we recognize: a- Paroxysmal tectonic events, occurred in the Early Miocene, responsible of the formation of the thrust slices verging towards the W and SW as well as backthrusts verging towards the E and NE. These backthrusts appeared after the blockage of the thrust slices by the Fiysch nappes situated in a more external position, and are interpreted as antiformai stack phenomena. b- Post - paroxysmal tectonic events with lesser importance, alternating as distensive and compressive phases, occurred during the Middle and Late Miocene
Relación estructural entre los cuerpos peridotíticos situados al Norte y al Sur del Estrecho de Gibraltar
(Sociedad Geológica de España, 1994) Sánchez Gómez, Mario; García Dueñas, V.; Muñoz, Mercedes; Balanyá, Juan Carlos
The peridotite bodies of the Bedes and Rif, on either side of the Strait of Gibraltar, are intercaled among the highest units of the Alpujarride complex. Before Miocene times, they must have constituted an uitramaficsiab (several kilometers thick). This former slab was fragmented by large extensionai structures developed during the formation of the Gibraltar Arc and the Alboran Basin
Registro metamorfico de alta presión-baja temperatura en la unidad de Jubrique e imbricaciones de Benarrabá (Cordillera Bético-Rifeña)
(Sociedad Geológica de España, 1994) Azañón, José Miguel; Balanyá, Juan Carlos; García Dueñas, V.
The presence of carpholitep seudomorphs and the kyanite-chloritoid-chlorite association in the Jubrique unitphy/iites and in the Benarrabá imbrications indicates metam rphic conditions of T < 450º C and P> 8 Kb. This means that these units were collisionally buried under crustal tectonic elements with a thickness of more than 20 Km.
Mise en evidence d'une structure diapirique déformée au niveau de la partie basale du Massif des Beni-Bousera (Rif interne, Maroc)
(Sociedad Geológica de España, 1994) Draoui, M.; Tabit, A.; El-Baghdadi, M.
La région basale du massif uitrabasique des Beni-Bousera correspond pétrographiquement à des lherzolites à spine/le avec des textures à gros grain et porphyrodastique à gros grain. Les données microstructurales et de ia fabrique du réseau de i'oiivine laissent suggérer une structure diapirique dont le diamètre ne dépasse pas un kilomètre. Une telle structure subirait une déformation plastique sous des conditions généralement de très haute température
Les failles normales a faible pendage du Rif interne (Maroc) et leur effet sur l'amincissement crustal du domaine D'Alboran
(Sociedad Geológica de España, 1994) Chalouan, Ahmed; Ouazani-Touham, A.; Mouhir, L.; Saji, R.; Benmakhlouf, M.
Several low angle, shallow dippinng normal faults are described from the internal domaine of the Rif chain. They dip gently towards the Alboran sea and cause important omissions in the stratigraphictectonic pile. These extensionai faults cut through the Ghomaride and Sebtides units and allow explaining the occurrence of flysch klippes overlying the Ghom arides nappes. The age of this extensionai event corresponds to that of the SerravaHan rifting stage of the Alboran sea
Le Bassin pliocène intramontagneux de Tirinesse et son mode d'ouverture (Rif interne, Maroc)
(Sociedad Geológica de España, 1994) Saji, R.; Chalouan, Ahmed
Tirinesse basin is opened by two NE-SW and NW-SE high angle normal fault systems. These contemporaneous faults belong to the iate-Piiocene rifting stage with bidirectional extensionai stress field
La Sierra Alhamilla (Beticas orientales), una ventana extensional abierta en el basamento de la cuenca Miocena de Alboran
(Sociedad Geológica de España, 1994) Martínez Martínez, Javier
The Alpujarride/Nevado-Filabride boundary exposed in the Sierra Alhamilla is a detachment fault belonging to the Fiiabres Extensional System (FES), a pronouncedly asymmetric system with a westsouthwestward transport direction. It was active during the Serravallian and folded during the Upper Tortonian-Messinian times. The FES geometry suggests a complex extensional history with more than one episode of norm al faulting. There are listric fans coalescing to a floor fault at shallow le vels and extensional duplexes at the deeper ones. The duplexes formed by migrating footwall faults, horses being bounded by out-of-sequence faults and inactive tilted faults belonging to the overlying listric fans
La falla normal de bajo ángulo de Tejeda: un ejemplo de la deformación miocena en las Béticas centrales
(Sociedad Geológica de España, 1994) Alonso Chaves, Francisco Manuel; Orozco, Miguel; García Dueñas, V.; Mayoral Alfaro, Eduardo
The existence of a major extensional fault in Sierra Tejeda, Central Betics, developed during the middle Miocene, is evidenced. The Tejeda, Venta de Palma, Bentomiz and Alcaiceria units make up the hanging-wall o f the fault. These units are tilted tow ard the N and NE. The collapse of the thinned crust of Alboran Domain is related with extensional origin of the contacts between units. Middle MioceneTortonian age deposits of the Granada basin seal the Tejeda extensional fault (FET)
La distension de L'Oligocène supérieur à Burdigalien dans les nappes Ghomarides (Rif interne septentrional, Maroc)
(Sociedad Geológica de España, 1994) Ouazani Touhami, A.; Chalouan, Ahmed
The Ghomarides nappes are overlain by late OUgocene-eariy Burdigaiian moiassic deposits. These deposits show three successive extensional stages wich are oriented: 1- NE-SW during late Oligocene. 2- NW-SE duringAquitanian. 3- ENE-WSW during the early Burdigaiian
Interference pattern of Miocene extensional systems in the Alpujarride Complex (N of Sierra Nevada, Betic Cordillera)
(Sociedad Geológica de España, 1994) Crespo Blanc, Ana
During the Miocene rift in gof the Alboran Domain, various extensional systems developed. North of Sierra Nevada, in the Sierra de Baza region, two low-angle normal fault systems with subperpendicular extension directions, middle Miocene in age, dismembered the Alpujarride complex into extensional units with the geometric pattern of achocolate -tablet mega-structure
High-pressure, low-temperature metamorphism in the Sebtides nappes, northern Rif, Morocco
(Sociedad Geológica de España, 1994) Bouybaouene, M.; Goffé, B.; Michard, A.
On the southern bank of the Gibraltar strait, the Permian-Triassic phyllites of the Sebtides-Alpujarrides nappes yielded edogite and biueschist-fades relic assemblages. The various metamorphic units are juxtaposed through retrograde contacts. The HP-LTmetamorphism indicates an Alpine subduction event.
¿Existe un cuerpo peridolítico entre dos fallas extensionales en el margen noroccidental del Mar de Alborán?
(Sociedad Geológica de España, 1994) Vázquez Garrido, Juan Tomás; Vegas, Ramón; Villalaín, Juan José
An analysis of multichanell seismic reflection profiles leads to define the main extensional features in the nortwestern margin of the Alboran Sea. Two strong (high amplitude) characteristic reflectors have been interpretated as extensional faults; one of the m (R. 1 ) corresponds basement-cover fault, whereas the deepest one (R.2) is an intra basement fault. A n inversion of interval velocity has been associated with R.2 and points to the existence of an anomalous high-velocity body over R.2. The ocurrence of peridotitic outcrops in the Betic Cordillera, and the positive gravity anomalies in the continental margin, do suggest that our data can be explained by means of a peridotitic sheet-like bodys and wiched between two extensional faults in the basement of the northwestern continental margin of Alboran Sea
Evolution tectono-séd i mentai re alpine autour de l'Arc de Gibraltar et mise en évidence de la cinématique de remontée d'un dôme de l'Asténosphère depuis le Jurassique jusqu'au Néogène
(Sociedad Geológica de España, 1994) El Kadiri, Khalil; Olóriz, F.; Linares, A.
The peridotites of the betico-rifain internal zone can be explained by the rise again of the subcrustal domein the old Alboran slab. The tectono sedimentary evolution of rifa in internal and external zone, respectively at Mesozoic and Cenozoïc time, may specify the kinematic and age o f this rise again a n d to reconstruct it stage by stage
Evolution Néogène du bassin de Tétouan-Martil, Rif septentrional, Maroc
(Sociedad Geológica de España, 1994) Benmakhlouf, M.; Chalouan, Ahmed
Tetouan-MartHpost-nappes basin is opened by two rifting stages: the first in late Oligocene-Burdigalian times, is accompanied by ductile normal faults in Aquitanian-Burdigalian rocks; the second of post Burdigaiian and pre-PHocene age, has produced two low angle norma/ fault systems, trending NE-SW and NW-SE, leading to the collapse of this basin
Evolución rotacional de las Béticas externas occidentales a partir de estudios paleomagnéticos
(Sociedad Geológica de España, 1994) Villalaín, Juan José; Osete, M. L.; Vegas, Ramón; García Dueñas, V.
A paleomagnetic study in Upper Jurassic limestones from the Western Subbetics indicates that these rocks have undergone a widespread and pervasive remagnetization during the Neogene. The original primary Jurassic magnetization can also be recognized. These two paiaeodeclinations can be used to separate the rotational movements occurred between the Jurassic and the Neogene and since the Neogene to the present. It is concluded that: (!) The only rotational movement that has undergone this region between the Jurassic a n d the Neogene is d u e to the m ovem ent o f the Iberian plate. (2) S in c e the Neogene this area was affected by clockwise rotations (between 30 and 80°). (3) The Neogene remagnetization preserves the amount of rotations related to recent deformational events. (4) These results do question the age and the amount of rotations determined in previous, palaeomagnetic studies
Estructuras de deformación en sedimentos del Cuaternario reciente de la cuenca del Bajo Segura. (Alicante). Discusión sobre su posible origen sísmico
(Sociedad Geológica de España, 1994) Alfaro García, Pedro; Doménech, C.; Estévez, Antonio; Soria, Jesús M.
Aiming at recognizing the prints in the most recent sedimentary record due to earthquakes, able to develop liquefaction and fluidization in sediments (magnitude equal to or more than 5), we have studied eight boreholes, each about 40 m long, located in the Low Segura basin (Alicante, Spain). We have recognized disturbances due to the own boring activity, as well as others due to bioturbation, thixotropy in clayey levels and to what, in our opinion, is the effect of seismic shocks (microfaults, distorted lamination and fluid scape structures)
Estructura profunda del sector central de las Cordilleras Béticas
(Sociedad Geológica de España, 1994) Galindo Zaldívar, Jesús; González Lodeiro, Francisco; Jabaloy, A.
The analysis of the crustal structure of the central sector of the Betic Cordilleras, by means of deep reflection seismic profiles and gravimetry, shows that the Moho is nearly planar. The continental crust of the Iberian Massif probably continue below the Betic Cordilleras. The boundary of the Betic Cordilleras crust and the thin crust ofthe A/boran Sea is made along a narrow E-W trending band where the Moho probably dips more than 60s N. This band is located 10 to 20 Km north of the coast line. The crust in the Betic Cordilleras has detachments, and the large folds with northward vergence, related to the mam topographic features of the Internal Zones, do not deform the deep reflectors. The mam crustal structures shown in the geophysical models are consistent with the oblique convergent movement between the Eurasian and African plates
El despegue extensional de Lahsene y los jirones de serpentinitas del anticlinal de Taryat (Melilla, Rif)
(Sociedad Geológica de España, 1994) García Dueñas, V.; Balanyá, Juan Carlos; Sánchez Gómez, Mario
The Taryat anticline, between Melilla and the Cabo Tres Forcas, folds an extensional detachment fault with SW transport sense. The fault is sealed by Tortonian marine sediments that were also folded. The hanging wall of the detachment is made up of brecciated slates andred sandstones, and the footwall consists of phyllites with chloritoid. These rock formations can be respectively attributed to the Maiaguide and Alpujarride complexes. Several serpentinite slices form part of the fault breccia
Yacimientos de vertebrados en los materiales Paleógenos de la zona de Ulldemolins y Conca de Barbera, (Cuenca del Ebro, Tarragona): significado Estratigräfico
(Sociedad Geológica de España, 1994) Colombo Piñol, Ferrán; Moya, S.; Checa, L.; Agustí, J.; Köhler, M.
The Ulldemolins Complex, which is characterized by different lithotypes, contains several types of fossil remains such as ostracoda, gastropoda, charophyta and micromammalia. This fossil association suggests that the Complex was deposited during the Culsian-Bartonlan time span. The outcrops located near the Ulldemolins village, which are characterized by mammalian remains, suggest that lower levels of Ulldemolins Complex were deposited during the Culslan time span. The outcrops located in the Conca d e Barberà area Indicate that the levels of the Montblanc Formation were deposited during the Bartonian-Pnabonian time span. The outcrops located near Vimbodi area suggest that the levels of Biancafort Fm were deposited during Lower Oligocene times
Unidades tectosedimentarías y rupturas en la Cuenca de Lorca (Murcia)
(Sociedad Geológica de España, 1994) Guillén Mondéjar, F.; Rodríguez Estrella, Tomás; Arana, R.; López Aguayo, F.
The complementary use of the mineralógical and tectosedimentary analysis has allowed to establish five tectosedimentary units (TSU) in the Lorca Basin dated from the upper Burdigalian to the Pliocene. They were originated in marine environments with entrance of cotinental contributions except for the TSU-5, that has a fluvial-lacustrine origin. The absence of two tectosedimentary units at the north of the basin supported the existence of a fracture in the middle of the basin that has conditioned their space-temporal evolution

Browse

Recent Submissions