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S8 - Late Neogene basins evolving in the Eastern Betic transcurrent fault zone: an illustrated review
- Edited by Peter F. Friend, University of Cambridge, Cristino J. Dabrio, Universidad Complutense, Madrid
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- Book:
- Tertiary Basins of Spain
- Published online:
- 04 August 2010
- Print publication:
- 26 January 1996, pp 372-386
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Summary
Abstract
Late Neogene sedimentary basins evolved within a wide transcurrent shear zone which passes through the Eastern Betic zone from the NE to the SW, and constitutes a segment of the major trans-Alboran shear zone. During the whole Neogene this structural corridor was subjected to a near-North–South compression resulting from the Iberia–Africa collision. As usual in wrench tectonics, compressional and extensional areas evolved at the same time within the structural corridor and controlled the development of two types of basin: groove-shaped faulted synclines and grabens. During the past ten million years, the direction of regional shortening varied between NW–SE and N–S, with important consequences for the kinematics of faulting and the sedimentary processes. Diversified magmatic activity, concentrated within the shear zone, interfered with the tectonic and sedimentary processes, especially during Tortonian times. The different magmatic products, originating from crustal (anatexis) and mantle lineages were telescoped within the corridor (e.g. Cabo de Gata), without any geochemical polarity indicative of a Miocene subduction zone. The major NE–SW trend of faults is deeply rooted in the lithosphere and marks the boundary between two different crustal slabs. The eastern slab is thinner and denser and has recorded an important late Miocene thermal anomaly. The basin evolution was greatly influenced by the properties of this hot and thin crust, which was particularly malleable under tectonic stress.
S1 - The Betic Neogene basins: introduction
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- By CH. Montenat
- Edited by Peter F. Friend, University of Cambridge, Cristino J. Dabrio, Universidad Complutense, Madrid
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- Book:
- Tertiary Basins of Spain
- Published online:
- 04 August 2010
- Print publication:
- 26 January 1996, pp 321-322
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Summary
The Betic Cordilleras stretch across the southern part of Iberia for about 650 km, from Cabo de la Nao (south of Valencia), in the east, to Cadiz, in the west. These Cordilleras consist of a complex assemblage of different geological domains (Figs. 1 and 2).
The External and Internal Zones correspond to different continental blocks, the southern Iberian paleomargin and the Alboran block respectively, juxtaposed along the complex, ENE-WSWtrending wrench corridor, the North Betic Wrench fault (Fig. 2A).
The External Zone includes the following domains: 1. the Prebetic autochthonous folded domain, linked northwards to the Meseta; and 2. the Subbetic allochthonous units overthrusting the Prebetic northwards.
The Prebetic and Subbetic are composed of sedimentary series ranging from Triassic to Miocene in age. The Late Triassic evaporites acted as a major level of detachment and have played an important part in the tectono-sedimentary development.
The Internal Zone is composed of numerous allochthonous units: the Flysch, the Dorsal unit, and a pile of nappes of sedimentary and varied metamorphic rocks, mainly altered Palaeozoic and Triassic rocks (e.g. from the base to the top, the Nevado-Filabrides, Alpujarrides and Malaguides nappes).
Neogene successions are widely involved in the polyphase structures of the different domains; they display a great diversity of facies and deformation. It must be emphasised that the Betic orogen was deformed to a major extent during Miocene times, when large areas of various Betic domains were still drowned by the sea, often producing deep marine environments.
S5 - Miocene basins of the eastern Prebetic Zone: some tectono sedimentary aspects
- Edited by Peter F. Friend, University of Cambridge, Cristino J. Dabrio, Universidad Complutense, Madrid
-
- Book:
- Tertiary Basins of Spain
- Published online:
- 04 August 2010
- Print publication:
- 26 January 1996, pp 346-352
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Summary
Abstract
The Miocene series of the eastern Prebetic domain include Aquitanian to early Tortonian marine deposits and a late Tortonian to Messinian–Early Pliocene continental sequence. These deposits are contemporaneous with different episodes of folding and faulting related to the variations of the compressional axis, between N–S and NW–SE. Numerous unconformities and synsedimentary or sealed structures illustrate the different stages of development of Miocene synorogenic basins and give an accurate chronology of the tectonic history of the eastern part of the External Betic Cordilleras.
Introduction
The eastern Betic Cordilleras include three major geological domains, from the North to the South (Fig. 1A): 1. the Prebetic autochthonous domain; 2. the Subbetic allochthonous units, overthrusting northwards the Prebetic domain; Prebetic and Subbetic are referred to as the external zone of the Betic Cordilleras; and 3. the internal allochthonous zone composed of a pile of alpine nappes, including sedimentary and various metamorphic rocks; this domain is separated from the external zone by a major ENEWSW-trending wrench-fault corridor (the North Betic wrench fault).
This study is dedicated to the Miocene basins evolving in the eastern part of the Prebetic domain (Fig. 2).
The eastern segment of the Prebetic domain is a folded ENE–WSW-trending zone. The folds are elongated structures often faulted and thrusted northwards. Some minor fold axes are twisted with a NE–;SW to N–S orientation. NE–SW faults have recorded sinistral or reverse-sinistral movements. NW–SE faults cut through the folds; they acted as normal faults, often reactivated with dextral movement.
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