Pascual Rivas

• Phd
• University of Granada

The Toarcian ammonitico rosso facies were widespread in the Mediterranean Tethys (between 15 and 30°N latitude) in the North Gondwana Paleomargin (Apulian promontory and North African Margin) and southern Iberian Paleomargin (Betic Cordillera). These facies were associated with epi-oceanic slopes of a sedimentary swell-trough system related to the...

A detailed carbon-isotope stratigraphic study for the uppermost Pliensbachian‒lowermost Aalenian interval in the Median Subbetic palaeogeographic domain (External zones of the Betic Cordillera, southern Spain) has been carried out. During the Early Jurassic, the Median Subbetic, which represents a typical basin of the Hispanic Corridor connecting t...

A taxonomie study has been carried out on scallops (family Pectinidae: Mollusca, Bivalvia) occurring in the lower-earliest middle Pliocene deposits of the Campo de Dalías, Almería-Níjar Basin, and Carboneras Basin (province of Almería, SE Spain). The recently proposed suprageneric phylogenetic classification scheme for the family (Waller, 2006a) ha...

Martin, Jose M., Braga, Juan C. & Rivas, Pascual 1989 07 15: Coral successions in Upper Tortonian reefs in SE Spain. Lethaia, Vol. 22, pp. 271–286. oslo. ISSN 0024–1164, During the Upper Tortonian (Upper Miocene), the Almanzora river corridor, a small Neogene basin in SE Spain, harboured coral reefs growing in three different environments: in fan d...

The Chicxulub impact event led to a worldwide deposition of impact materials originated from target rocks and the vaporized bolide. Relative contributions of both types of material to the K/T ejecta deposits vary with distance to the crater site. At distal sites (e.g., Agost and Caravaca in the SE of Spain) a major contribution of extraterrestrial...

In this paper we present a synthesis on the Toarcian/Aalenian (Lias/Dogger) boundary in the Iberian Peninsula. We have selected in each domain the most representative areas and sections in which this boundary is represented: Fuentelsaz and Moyuela sections in the Iberian Cordillera, sierra de Ricote and cerro Méndez in the Betic Cordillera, and São...

Hutchinson's ('89) road-holding model states that spiral orna- ments of the snail shell (keels and low-curvature areas) dictate the growth path of the subsequent whorl, which in turn gives the signal for attachment of the next whorl. Experiments were performed with two species of the terres- trial snail Sphincterochila in order to test the role of...

Lower Domerian (upper Pliensbachian) Entolium shell concentrations characterise the transition between shallow-water carbonates and pelagic marls and marly limestones in the middle Liassic from the southern part of the Median Subbetic, one of the subdomains of the southern passive margin of the Iberian Massif. Rudstones and floatstones of Entolium...

Quantitative analysis of pectinid (Bivalvia) assemblages in the Lower Pliocene deposits of the Almeria-Nijar and Poniente basins in southeastern Spain reveals changes in the taphonomical attributes, taxonomical composition, and shell morphology of these assemblages in relation to the sediments in which they occur. The lower Pliocene deposits in bot...

A positive δ13C excursion reveals an oceanic anoxic event in the Subbetic, corresponding to the westernmost end of the Tethys during the Early Jurassic. This positive δ13C excursion exists in five stratigraphic sections consisting of Lower and Middle Toarcian pelagic sediments. The positive δ13C excursion in the Subbetic is located in the upper par...

Middle Miocene coral-oyster patch reefs crop out at Murchas. They are irregularly shaped masses of coral-oyster boundstone, up to 18 m wide and 3-4 m high, that developed on the outer part of a homoclinal ramp, seaward of some sand shoals, in a mixed carbonate-terrigenous environment. Heliastrea is the predominant coral. Porites, Tarbellastraea and...

The Toarcian-Aalenian boundary has been studied accurately for the first time, in three areas of the Subbetic domain (Southern Spain). The successive ammonite assemblages have permitted to distinguish the uppermost Toarcian, Aalensis Zone (Mactra, Aalensis and Buckmani Subzones), and Lower Aalenian, Opalinum Zone, (Opalinum and Comptum Subzones). I...

The Iznalloz section (Betic cordillera, Spain) provides a continuous outcrop (20 m thick) of Toarcian ammonitico rosso limestones with all the ammonite zones defined in the Betic realm. The characteristic magnetization direction for each sample was obtained by detailed thermal demagnetization and was stable from about 450 to 560°C. The magnetic pol...

Several new fossiliferous localities were found in the northern part of the Granada Basin. One of these, Purcal 4, yielded a rich fauna of micromammals, that clearly demonstrates an Early Pliocene age of the beds.

The origin of ammonite sutures is one of the most interesting open problems in paleontology. Present theories of suture formation deal with function rather than morphogenesis. Here we present a study showing that sutures are scale-invariant. In each of ten different ammonite genera, the ontogenetic sequence of the suture can be characterized by the...

The Iznalloz section (Betic Cordillera, Spain) provides a complete outcrop of Toarcian ammonitico rosso limestone with all the Ammonite zones defined in the Subbetic realm. High density sampling (> 100 cores along the 20m thick section) and detailed thermal demagnetization allow establishing a reliable magnetic polarity sequence which extends from...

In the Toarcian beds of the Subbetic zone some Bouleiceratinae have been found (Leukadiella, Frechiella and Paroniceras), this complements the paleobiogeographic knowledge of the Mediterranean Toarcian. On the other hand the relative abundance of Alocolytoceras in the area suggest that this genus is not a precise paleobiogeographic index. -English...

Two Lower Liassic sections of the Banos de Alhama de Granada outcrop are studied. The Hettangian and Sinemurian ammonite assemblages are detailed and a reinterpretation of the stratigraphy of the outcrop made.The ammonites collected show a clear mediterranean character. A biostratigraphy for the Hettangian and Sinemurian can be made but the correla...

Most of the Tethyan species usually attributed to the genera Platypleuroceras, Uptonia and Dayiceras (Polymorphitidae) are in reality forms phylogenetically related to Metaderoceras, but which show convergence in their morphology. Their originality justifies the creation of a new genus, Dubariceras and two new species, D. dubari and D. freboldi.The...

The main events characterizing the Mesozoic palaeogeographic evolution of the External Zones of the Betic Cordillera are outlined. The Triassic sediments show a 'germanic' type lacies over the entire region, ending with Late Triassic evuporites and variegated clays of Keeper facies. At the beginning of the Jurassic a transgression takes place, and...

Se analizan estructuras de los estratos que acompañan a las pisadas de dinosaurios fósiles de La Rioja teniendo en cuenta la respuesta de las rocas sedimentarias en su estado no compactado y después de la diagénesis. El trabajo se inicia con la descripción de las estructuras asociadas a los autopodios y que son consecuencia de sus características b...

Colección que concibe al protocolo como un campo de estudio y acción que, más allá de las buenas maneras, constituye un marco normativo y orientador para garantizar una interacción social pacífica en la vida cotidiana. Para ello, aborda el protocolo en relación con eventos particulares, como ceremonias reales, congresos y seminarios, banquetes, etc...