Evolución geodinámica de la fosa del Empordà y las Sierras Transversales

The Emporda basin, together with the half graben system of the Sierras Transversales, form a segment of the European Rift, which is defined here by the NW-SE-trending fault system of northeastern Catalonia.The study area, which partially includes the Sierras Transversales and the southem margin of the Emporda basin, is internally structured by normal faults with listric geometry. Those with measured dip slips of about 1,000 meters are here called main faults; those located in the hanging walls of the main ones are called minor faults, and their dip slips are, at least, lesser in one order of magnitude. The hanging walls of the main faults hold half graben basins, with a sedimentary infill mainly neogene in age in the Emporda, and of quaternay age in the Sierras Transversales. Both areas are geologically bounded by the Camós-Celra fault. This rift segment is also characterized by the occurence of numerous volcanic emission centres. The timing of activity and burial of each fault, constrained by the ages of the associated sediments and vulcanism, suggest a piggy-back sequence of propagation from Miocene to recent times. The geological cross-section constructed from surface data, allowed us the elaboration of a geometric model in clepth for the whole fault system, usiug the inclined shear method. The calculated extension from this method gives us a value of B=1.27. On the other han4 the very high calculated magma ascent rates strongiy constrain the structure in the footwall (crust); subsequently, high angle discontinuities favouring a very fast magmatic ascent have to be definied. These discontinuities would form two imbricate systems (extensional duplexes), with a roof detachment coinciding with the floor detachment of the shallow fault system and a floor detachment located in the MOHO discontinuity. A similar crustal structuration is observed in the neighbouring segment of the Gulf of Lions

Marine and Transitional Middle/Upper Eocene Units of the Southeastern Pyrenean Foreland Basin (NE Spain)

The stratigraphic basis of this work has allowed the use of larger foraminifers in the biostratigraphic characterisation of the new Shallow Benthic Zones (SBZ). This part of the volume presents a description of the sedimentary cycles formed by the transgressive-regressive systems of the Lutetian and Bartonian in the southeastern sector of the Ebro Foreland Basin.Concerning the Lutetian deposits studied in the Amer-Vic and Empordà areas, four sedimentary cycles have been characterised. The first and second are found within the Tavertet/Girona Limestone Formation (Reguant,1967;Pallí,1972), while the third and fourth cycles cover the Coll de Malla Marl Formation (Clavell et al.,1970), the Bracons Formation (Gich,1969,1972), the Banyoles Marl Formation (Almela and Ríos,1943),and the Bellmunt Formation (Gich,1969,1972). In the Bartonian deposits studied in the Igualada area,two transgressive-regressive sedimentary cycles have been characterised in the Collbàs Formation (Ferrer,1971),the Igualada Formation (Ferrer,1971),and the Tossa Formation (Ferrer,1971). The Shallow Benthic Zones (SBZs)recognised within the Lutetian are the following:SBZ 13, from the Early Lutetian, in the transgressive system of the first cycle;SBZ 14,from the Middle Lutetian, in the second cycle and the lower part of the transgressive system of the third cycle; SBZ 15,from the Middle Lutetian, in the remaining parts of the third system; SBZ 16, from the Late Lutetian,throughout the fourth cycle.The association of larger foraminifers in the first and second cycles of the Bartonian in the Igualada area has been used as the basis for the definition of SBZs 17 and 18 recognised in the Bartonian of the western Tethys

Los ciclos sedimentarios del Eoceno medio y superior en el sector NE de la depresión del Ebro (zona de Bergas-Vic). Caracterización de sus Iímites

In the middle and upper Eocene strata of the South Pyrenean foreland basin, three sedimentary cicles have been distinguished. These cycles are bounded by angular uncorfirmities, each cycle being related to the development of a particular thrust system. The stiking of the thrust systems is recorded by rhe angular uncorformities that bound the cycle

Stratigraphy of the Montgrí Massif

The creiaceous carbonates forming the Montgri massif (Berriasian ? to Santonian) were deposited in the southern, marginal areas of the basin. As they sedimented in shallow platform environments, they were very sensible to sea-level changes. Thus, the section is divided into seven allostratigraphic units (NASC, 1 983), numbered from 1 (o 7. Some of their bounding discontinuities include erosion with subaerial exposure (lower boundaries of the units 2, 4, 5 and 7), paleokarst (2 and 4) and lateritic-soil developments (lower boundary of the unit 2). The units numbered 2, 4 and 6 respectively show onlap relationships over truncated underlying strata, and the lower boundary of the unit number 7 is a disconformity. The unit number 3 is bounded by a discontinuity recording a non-depositional event, and the bottom of the unit 5 is a condensed section. The units 2 (Aptian) and 6 (Coniacian to Santonian I) record the activity of exlensional faulting along two structures known in outcrop; one of them can be observed in its original shape, and the other was inverted during the alpine compression. The uppermost strata in the unit 2 and the unit 7, respectively postdate these extensional structure

Marine and Transitional Middle/Upper Eocene Units of the Southeastern Pyrenean Foreland Basin (NE Spain)

The stratigraphic basis of this work has allowed the use of larger foraminifers in the biostratigraphic characterisation of the new Shallow Benthic Zones (SBZ). This part of the volume presents a description of the sedimentary cycles formed by the transgressive-regressive systems of the Lutetian and Bartonian in the southeastern sector of the Ebro Foreland Basin. Concerning the Lutetian deposits studied in the Amer-Vic and Empordà areas, four sedimentary cycles have been characterised. The first and second are found within the Tavertet/Girona Limestone Formation (Reguant, 1967; Pallí, 1972), while the third and fourth cycles cover the Coll de Malla Marl Formation (Clavell et al., 1970), the Bracons Formation (Gich, 1969, 1972), the Banyoles Marl Formation (Almela and Ríos, 1943), and the Bellmunt Formation (Gich, 1969, 1972). In the Bartonian deposits studied in the Igualada area, two transgressive-regressive sedimentary cycles have been characterised in the Collbàs Formation (Ferrer, 1971), the Igualada Formation (Ferrer, 1971), and the Tossa Formation (Ferrer, 1971). The Shallow Benthic Zones (SBZs) recognised within the Lutetian are the following: SBZ 13, from the Early Lutetian, in the transgressive system of the first cycle; SBZ 14, from the Middle Lutetian, in the second cycle and the lower part of the transgressive system of the third cycle; SBZ 15, from the Middle Lutetian, in the remaining parts of the third system; SBZ 16, from the Late Lutetian, throughout the fourth cycle. The association of larger foraminifers in the first and second cycles of the Bartonian in the Igualada area has been used as the basis for the definition of SBZs 17 and 18 recognised in the Bartonian of the western Tethys.This research was supported by DGICYT grant PB 98-1293, and is a contribution to IGCP 393 of the Grup Consolidat de Recerca "Geodinàmica i Anàlisi de Conques" of the Barcelona University and the Research Commission of the Generalitat de Catalunya.Peer reviewe

The Neogene sedimentation in the margins of the Empordá basin

The Empordci basin is located at the northeast of the Iberian Peninsula in this Basin several deltaic and alluvial fans were deposited during the Neogene. Three of them are aged Miocene and nine Pliocene. The location, thickness and evolution of the Neogene fans are related to the distribution and features of the faults appearing in the Emporda basin. Such fans are arranged in a semicircular way at the borders of the basin. Their paleocurrents distribution is radial towards the center of the basin. Both clasts, litologics and paleocurrent analysies depict the exact source area of each fan. In the eastern part of the Cavarres fan only a single marine facies outcrop can be recognized, which is attributed to the upper Miocene. The pliocene fan deltas are partially correlable with the marine facies of the same age, located in the center of the basin. The pliocene sediments at Viladomal are interpreted as a Cilbert-type delta with northwest wards paleocurrents, and it was deposited in the mouth of the paleo-Dard river (Corredor d'Albons

An inventory of the marine and transitional Middle/Upper Eocene deposits of the Southeastern Pyrenean Foreland Basin (NE Spain)

In the southeastern Ebro Foreland Basin, the marine deposits of Lutetian and Bartonian age show excellent outcrop conditions, with a great lateral and horizontal continuity of lithostratigraphic units. In addition, the rich fossil record -mainly larger foraminifers-, provides iostratigraphic data of regional relevance for the whole Paleogene Pyrenean Basin, that can be used for the Middle Eocene biocorrelation of the western Tethys. This contribution is a sedimentary and biostratigraphic synthesis of the basic outcrops and sections of the Lutetian and Bartonian marine and transitional deposits in the southeastern sector of the Ebro Foreland Basin

An inventory of the marine and transitional Middle/Upper Eocene deposits of the Southeastern Pyrenean Foreland Basin (NE Spain)

In the southeastern Ebro Foreland Basin, the marine deposits of Lutetian and Bartonian age show excellent outcrop conditions, with a great lateral and horizontal continuity of lithostratigraphic units. In addition, the rich fossil record -mainly larger foraminifers-, provides iostratigraphic data of regional relevance for the whole Paleogene Pyrenean Basin, that can be used for the Middle Eocene biocorrelation of the western Tethys. This contribution is a sedimentary and biostratigraphic synthesis of the basic outcrops and sections of the Lutetian and Bartonian marine and transitional deposits in the southeastern sector of the Ebro Foreland Basin