23 documents found, page 1 of 3

Ordovician–Silurian transition in the Central-Iberian Zone: Just a stratigraphi...

ABSTRACT: The Ordovician-Silurian boundary in the Central-Iberian Zone is often considered a normal stratigraphic transition. Nevertheless, in studies carried out in Portugal (e.g. Espinhosela, São Mamede and Buçaco areas) and Spain (e.g. Alcañices Synform) this contact is marked by the development of shear zones subparallel to the lithostratigraphic units. Ongoing structural mapping in Celorico de Basto (Marão...

Ordovician – Silurian transition in the Central-Iberian Zone: Just a stratigrap...

The Ordovician-Silurian boundary in the Central-Iberian Zone is often considered a normal stratigraphic transition. Nevertheless, in studies carried out in Portugal (e.g. Espinhosela, São Mamede and Buçaco areas) and Spain (e.g. Alcañices Synform) this contact is marked by the development of shear zones subparallel to the lithostratigraphic units. Ongoing structural mapping in Celorico de Basto (Marão region) s...

Transição Ordovícico-Silúrico na Zona Centro-Ibérica: apenas um contacto estrat...

SUMMARY: Although the Ordovician-Silurian transition in the Central-Iberian Zone is usually considered a normal stratigraphic one, recent studies shows that often the black-shales of the Lower Silurian control the development of shear zones subparallel to the main layers. This behavior has been observed, not only in the Marão-Alvão region, but also in other sectors like, the synclines of S. Mamede, Mação and Bu...

Cambrian-Ordovician Transition in the Northern Domains of Central-Iberian Zone;...

In the northern sectors of the Central-Iberian Zone the transition of the Lower Ordovician over the underlying sequences always shows evidence of the Toledanian phase. The effects of this pre-Armorican Quartzites deformation are highly heterogeneous. In most of the cases it is only shown by an important erosive level giving rise to a disconformity, while in other situations it corresponds to a strong angular un...

Strain partitioning in the Variscan deformation of the Marão domain (Central Ib...

formation of the Ibero-Armorican Arc, a major structure in the SW Variscan orogeny, induced in most of its southern Iberian branch a heterogeneous sinistral transpressive regime. The presence of pre- and syn-orogenic steep planar anisotropies subparallel to the main WNW-ESE structural trend, gave rise to an important strain partitioning of the Variscan deformation. This lead to the lateral juxtaposition of narr...

A fase de deformação sarda na Zona Centro-Ibérica

Ao longo da Zona Centro-Ibérica a transição entre as sequências de idade Câmbrica e as sequências ordovícicas sobrejacentes evidencia sempre a actuação da fase Sarda s.l. No entanto, a forma como se manifesta esta deformação de idade pré- Quartzito Armoricano é bastante heterogénea: na generalidade dos casos apenas se evidencia através de um nível erosivo significativo que marca uma disconformidade, enquanto no...

Arco Ibero-Armoricano: indentação versus auto-subducção

No Varisco da Ibéria têm sido identificadas diversas macroestruturas arqueadas cuja caracterização e génese é objecto de controvérsia. Neste trabalho discutem-se os argumentos associados a cada uma destas estruturas, bem como os processos de formação dos arcos Ibero-Armoricano e Cantábrico. Os elementos existentes sugerem uma génese polifásica, onde a indentação de um promontório principal da Gondwana aparece c...

A Review of the Arcuate Structures in the Iberian Variscides; Constraints and G...

In the Iberian Variscides several first order arcuate structures have been considered. In spite of being highly studied their characterization, formation mechanisms and even existence is still debatable. Themain Ibero-Armorican Arc (IAA) is essentially defined by a predominantNW–SE trend in the Iberian branch and an E–Wtrend in the Brittany one. However, in northern Spain it presents a 180° rotation, sometimes ...

The Ibero-Armorican arc: indentation versus self-subduction

In the Iberian Variscides it is possible to distinguish major arcuate structures; although highly studied, their characterization and genesis are still a matter of controversy. The main Ibero- Armorican Arc (IAA) is essentially defined by a NW–SE trend in the Iberian branch and an E–W trend in the Brittany branch; however, in northern Spain it is rotated 180º, sometimes known as the Cantabrian Arc (CA). The rel...

Evolução estrutural dos sectores setentrionais do Autóctone da Zona Centro-Ibérica