Fernández López, Sixto Rafael

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First Name
Sixto Rafael
Last Name
Fernández López
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Geodinámica, Estratigrafía y Paleontología
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Now showing 1 - 6 of 6
  • Publication
    Primera fase de post-rifting: Jurásico Inferior y Medio.
    (Sociedad Geológica de España, 2004) Gómez Fernández, Juan José; Fernández López, Sixto Rafael; Goy, Antonio; Vera, J.A.
  • Publication
    The Iberian Middle Jurassic carbonate-platform system: Synthesis of the palaeogeographic elements of its eastern margin (Spain)
    (Elsevier, 2006) Gómez Fernández, Juan José; Fernández López, Sixto Rafael
    During the Middle Jurassic, the domain of the Iberian and Catalan Coastal ranges of eastern Spain was occupied by a system of fault-controlled carbonate platforms that flanked the Iberian Massif to the East. This platform system marked the transition between the shelves of the Alpine Tethys and the Central Atlantic Ocean. The palaeogeographic reconstruction of the Iberian Middle Jurassic platform system is based on more than 199 surface sections and 37 wells. From southwest to northeast, eight main palaeogeographic elements with associated characteristic facies are recognized. These represent a system of horsts and grabens. In the southwest, the Internal Castilian Platform is characterized by the frequently dolomitized oolitic and restricted facies of the Yemeda Formation. To the northeast, the NW-trending open-marine carbonate environments of the External Castilian and Aragonese platforms were separated by the fault-controlled El Maestrazgo High that is characterized mainly by the dolomitized Rafales Formation. The External Castilian and Aragonese platforms consist from bottom to top of the microfilament mudstones to wackestones of the El Pedregal Formation, the bioclastic and oolitic grainstones to packstones of the Moscardon Formation, and the Domen˜o Formation, that reflects a return to an open-marine low-energy wackestone to mudstone facies, locally containing patches of oolitic grainstones. The highly subsiding Tortosa Platform, represented by the Sant Blai, Cardo and La Tossa formations, is bounded by the dolomitic facies deposited on the El Maestrazgo and the Tarragona highs, and by the Catalan Massif where no Middle Jurassic deposits have been recorded. The open-marine facies and condensed sections of the Beceite Strait separated the Aragonese and Tortosa platforms. A regional stratigraphical gap spanning the upper Callovian Lamberti Zone to the lower Oxfordian Cordatum Zone is evident. A system of northwest- and northeast-trending normal faults controlled thickness and facies distribution. Data from the Iberian carbonate-platform system indicate that expanded sections were not necessarily associated with open-marine environments. Condensed and expanded sections are developed in open and restricted-marine facies, even on such palaeogeographic highs as the El Maestrazgo High. Restricted and shallow-marine environments occasionally developed in parts of the External Castilian Platform.
  • Publication
    The Middle Jurassic eastern margin of the Iberian platform system (eastern Spain). Palaeogeography and biodispersal routes of ammonoids.
    (Università degli studi di Milano. Dipartimento di Scienze della Terra "A. Desio", 2004-04) Fernández López, Sixto Rafael; Gómez Fernández, Juan José
    From a sedimentological and palaeogeographical point of view, in the eastern margin of the Iberian platform system, Middle Jurassic deposits are represented by a thick pile of carbonates with minor marls interbedded. Different facies, within the Tortosa, Aragonese and Castilian platforms, pertain to two categories: internal platform and external platform facies. A system of extensional faults was the major factor determining the differentiation of several shallow, carbonate, epicontinental platforms. The so-called Iberian Basin was a shallow intracratonic platform system, in which a relatively deep extensional basin (the Catalan Basin) started to be differentiated during the late Bajocian. In the eastern part of this faulted platform system, the occurrence of a listric fault, dipping towards the east, conditioned the development of a late Bajocian differentiated subsident area named the Tortosa Platform. From a palaeobiogeographical point of view, the ammonite fossil assemblages of the Iberian platforms are composed of Sub-Mediterranean taxa. At the eastern margin of the Iberian platform system, the appearance and distribution of shells of ammonoids were taphonomically and ecologically controlled by regional changes of relative sea level. A Sub-Mediterranean zonation can be recognized, although most of the ammonites shells correspond to adult individuals arrived by necroplanktic drift from more open-marine or oceanic areas. The following criteria are relevant in recognizing the maximum deepening episodes in the Iberian platform system: colonization (including ontogenic development) of open-marine taxa, immigration of oceanic taxa and development of endemic species. In terms of Sequence Stratigraphy, the development of expanded, external platform sections in the Tortosa Platform during the Garantiana Biochron (late Bajocian) is noteworthy. During this episode, the Iberian platform system reached the maximum bathymetric values and acted as a biogeographical dispersal area for some taxonomic groups of ammonoids between the Western Tethys and the Proto-Atlantic.
  • Publication
    Jurásico Medio
    (Sociedad Geológica de España, 2004) Gómez Fernández, Juan José; Fernández López, Sixto Rafael; Vera, J.A.
  • Publication
    Las unidades litoestratigráficas del Jurásico Medio de la Cordillera Ibérica
    (Sociedad Geológica de España, 2004) Gómez Fernández, Juan José; Fernández López, Sixto Rafael
    Five lithostratigraphic units applicable to the different Middle jurassic palaeogeographical elements of the Iberian platform system are proposed. For the oolitic-dolomitic belt developed in the Internal Castilian Platform, the Yemeda Fm is proposed. To the mainly dolomitic facies which extends aver the El Maestrazgo High, the Rafales Fm is defined. Within the micritic external platform facies of the Castilian and Aragonese platforms, three formations have been recognized. The lower unit (El Pedregal Fm) is constituted of microfilament, mudstone to wackestone limestones. The middle unit (Moscardon Fm) is made up of bioclastic and oolitic, grainstone to packstone limestones. The upper unit (Domeño Fm) represents a return to the external low energy wackestone to mudstone facies, locally containing patches of oolitic grainstone facies.
  • Publication
    The Middle Jurassic eastern margin of the Iberian platform system
    (International Subcommission on Jurassic Stratigraphy, 2002) Fernández López, Sixto Rafael; Gómez Fernández, Juan José; Martire, Luca