Person:
Fernández López, Sixto Rafael

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First Name
Sixto Rafael
Last Name
Fernández López
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Geodinámica, Estratigrafía y Paleontología
Area
Paleontología
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UCM identifierORCIDScopus Author IDWeb of Science ResearcherIDDialnet IDGoogle Scholar ID

Search Results

Now showing 1 - 10 of 151
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    Nuevas perspectivas de la tafonomía evolutiva: tafosistemas y asociaciones conservadas
    (Estudios Geológicos, 1984) Fernández López, Sixto Rafael
    Varios conceptos básicos de la TafonoIDÍa evolutiva son tratados en este artículo. Hay una discusión general de los procesos principales que controlan la conservación tafofiÓmica. Diversos enfoques para la aplicación de la teoría de la comunicación al registro fósil han sido revisados y sintetizados. Los problemas de resedimentaciÓD versus retrabajamiento reciben .especial atención como fenómenos. tafonómicos. Se hacen algunas observaciones sobre el concepto ae condensación. [ABSTRACT] Several basic concepts of the evolutionary Taphonomy are examinated in this paper. There is a general discussion of the main processes controlling fossil preservation. Approaches for the aplication of communications theory to the fossil record are reviewed and surnmarized. The problems of redeposition (Umlagerung) vs reworking (Aufarbeitung) receives special attention as taphonomical phenomena. Sorne remarkst on the concept of condensation are made.
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    Bajocian ammonoids from Pumani River area (Ayacucho, Peru): Palaeobiogeographical and palaeoenvironmental implications for the Arequipa Basin
    (Journal of South American earth sciences, 2014) Fernández López, Sixto Rafael; Carlotto, Victor; Giraldo, Edwing; Chacaltana, César
    Deposits of the Socosani Formation in the Pucayacu and Pumani sections (Ayacucho Department, Peru), along several kilometres, have yielded Upper Bajocian ammonoid fossil-assemblages characterized by the occurrence of juvenile individuals belonging to endemic or pandemic genera, such as Megasphaeroceras and Spiroceras respectively. In addition, certain Bajocian genera relatively common in the Mediterranean-Caucasian Subrealm, but very scarce in the Eastern Pacific Subrealm, such as the strigoceratid Cadomoceras and the phylloceratid Adabofoloceras, occur in this area. According to the taphonomic, palaeoecological and palaeobiogeographical evidence from the Pumani River area, the maximum deepening, relative sea-level rise and oceanic accessibility of a BajocianeBathonian, second-order, transgressive/regressive facies cycle in the marine Arequipa Basin were reached during the Late Bajocian Niortense Biochron. However, synsedimentary regional tectonics in the Pumani River area disturbed this general deepening/shallowing cycle of the Arequipa Basin, particularly during the Late Bajocian post-Niortense time-interval of the Garantiana and Parkinsoni biochrons.
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    Sistemas tafonómicos: función y evolución
    (Revista española de paleontología, 1991) Fernández López, Sixto Rafael
    El sistema conceptual de la Paleontología ha sido radicalmente modificado desde el siglo pasado hasta la actualidad. La Paleobiología ha desarrollado nuevos conceptos, presupuestos, métodos y procedimientos. En la actualidad se requiere de una Táfonomía sistemista y evolucionista para garantizar la congruencia de los resultados paleontológicos. En el presente trabajo se explicita y discute el significado de algunos conceptos referentes a la funcionalidad y evolución de los sistemas tafonómicos. La producción tafogénica y la alteración tafonómica hacen que la fosilización, en vez de ser un proceso paleobiológico destructivo, sea un proceso negentrópico que no implica pérdida o disminución de la información paleobiológica y en el cual se incrementa la información tafonómica. Los conceptos de producción tafogénica y alteración tafonómica proporcionan los fundamentos teóricos para interpretar los mecanismos de fosilización. [ABSTRACT] The conceptual system ofPaleontology has beendrastically modified from the last century to the present, new concepts, methods, assumptions and paleobiological procedures having been developed. In the present state of knowledge a systemist and evolutionary taphonomy is required in order to guarantee the consistency of the paleontologicalresults. The meaning of some concepts concerning the functionality and evolution of taphonomic systems is discussed and precised. Such processes as taphogenic production and taphonomic alteration make fossilization become a taphonomic, negentropic process, in which taphonomic information increases and which does not involve any loss or(ceduction of paleobiologic information, instead of a destructive process. The concepts of taphogenic production and taphonomic alteration provide the theoretical foundations to intepretate the mechanisms of fossilization.
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    Criterios elementales de reelaboración tafonómica en ammonites de la Cordillera Ibérica
    (Acta geologica hispanica, 1984) Fernández López, Sixto Rafael
    Algunos moldes internos de ammonites, reelaborados, que están contenidos en calizas del Jurásico medio de la Cordillera Ibérica, muestran varias propiedades conservativas; los procesos de reelaboración tafonómica, por lo tanto, no deberían ser considerados como destructivos. Esta conclusión puede ser sacada de varios criterios observados y discutidos en este artículo. [ABSTRACT] Some ammonite steinkerns, reworked, that are contained in limestones from the Middle Jurassic Iberian Range, show several preservational features; processes of this kind therefore should not be called destructive. This conclusions can be draw from several criteria observed and discussed in this paper.
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    Taphonomy of an ammonite recorded association (Murchisonae Zone, Aalenian, Iberian Range, Spain). Palaeoenvironmental implications.
    (Abstracts and Programs. 6th International Symposium on the Jurassic System, 2002) Fernández López, Sixto Rafael; Martínez Gutiérrez, Gemma; Martire, Luca
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    Las unidades litoestratigráficas del Jurásico Medio de la Cordillera Ibérica
    (Geogaceta, 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.
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    The limit between biostratinomy and fossildiagenesis
    (Current Topics on Taphonomy and Fossilization, 2002) Fernández López, Sixto Rafael; Fernández Jalvo, Yolanda; Renzi, Miguel D.; Pardo Alonso, Miguel V.; Belinchón, Margarita; Peñalver, Enrique; Montoya, Plinio; Márquez Aliaga, Ana
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    Aalenian Tmetoceras (Ammonoidea) from Iberia: taxonomy, habitats and evolution.
    (Advancing Research on Living and Fossil Cephalopods: Proceedings of the IVth International Symposium on Cephalopods: Present and Past, held in Granada, Spain, July 14-18, 1996, 1999) Fernández López, Sixto Rafael; Henriques, María Helena Paiva; Linares Rodríguez, Asunción; Sandoval Gabarrón, José; Ureta Gil, María Soledad; Olóriz Aguilera, Federico; Rodríguez Tovar, Francisco J.
    Several hundred Aalenian Tmetoceras from the Iberian Peninsula (N Lusitanian Basin, Asturias, Basque-Cantabrian Basin, NE Cameros, NW Iberian Basin, Aragonese Platform, Tortosa Platform, Castilian Platform, Majorca and Betic Basin) have been reviewed. Two species of Aalenian Tmetoceras have been identified on the basis of morphological, biochronological and palaeobiogeographical data: T. scissum and T. regleyi. T. scissum was dominant among the Tmetoceras populations developed in the Betic and Lusitanian basins during Opalinum, Murchisonae and Bradfordensis biochrons. Populations composed by evolute individuals of T. scissum inhabited shelfal or oceanic environments. A chronocline, from rectiradiate and primitive forms to flexicostate and derived forms, can be recognized in these populations of T. scissum. In contrast, shallow epicontinental platforms were inhabited by involute individuals of T. regleyi. This second species was phyletically derived from T. scissum, representing an adaptive radiation from populations of shelfal or oceanic basins to populations of epicontinental platforms.
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    Le Toarcien, L'Aalenien et le Bajocien dans le secteur de Tivenys: nouvelles donnees biostratigraphiques
    (Strata. Série 2, Mémoires, 1985) Fernández López, Sixto Rafael; Mouterde, René
    Aux environs de Tivenys, la plupart des zones d'Ammonites du Toarcien inférieur au Bajocien supérieur ont pu être caractérisées dans les associations fossiles. Cependant, seul le Bajocien supérieur, sous le faciès "marnes de Cardo", présente une épaisseur notable et a été favorable à l'installation de certaines populations d'Ammonites. Les dépôts sousjacents, dont les épaisseurs ne dépassent pas quelques mètres, correspondent à des conditions plus instables (oolithes ferrugineuses....) Les associations fossiles observées correspondent le plus souvent à des coquilles flottées ou à des exemplaires remaniés (réélaborés). Les indices de bioturbation sont presque constants.
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    Rasgos geológicos del Jurásico de la Sierra de Reclot (Alicante)
    (Resúmenes de las comunicaciones y excursiones del Simposio Homenaje a Don Daniel Jiménez de Cisneros y Hervás : celebrado en Alicante, los días 4, 5, 6 y 7 de noviembre de 2004, 2004) Caracuel Martín, Jesús E.; Baeza-Carratalá, J.F.; Tent-Manclús, J.E.; Yébenes, A.; Fernández López, Sixto Rafael