37 research outputs found

    UPPER TRIASSIC SPHINCTOZOAN SPONGES FROM NORTHEN CALABRIA (SOUTHERN ITALY)

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    Three sphinctozan sponges: Amblysiphonella sp., Colospongia sp. and the new species Deningeria iannacei n. sp., are described from a loose boulder derived from Triassic dolomites ("Dolomia principale") of the Argentino valley in Northern Calabria (Southern Italy). All three genera are reported for the first time from Calabria. The sphinctozoans are associated with other sponges (inozoans, "sphinctozoans," "hydrozoans", chaetetids), "microproblematica", foraminifers, abundant worm tubes, biogenic crusts, and rare dasycladacean algae. The age of the association is referred to Upper Triassic (Norian-Rhaetian) on the basis of its similarity to the classic reef assemblages of Upper Triassic in the Tethys realm and by the close proximity of the boulder to the well dated (macrofauna) outcropping Upper Triassic carbonate successions.&nbsp

    THE MIDDLE-UPPER TRIASSIC OF THE SAN DONATO UNIT AUCT. (NORTHERN CALABRIA): STRATIGRAPHY, PALEOGEOGRAPHY AND TECTONIC IMPLICATIONS

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    In this paper are presented  stratigraphic and sedimentological data on the carbonate successions occurring in the Cozzo del Pellegrino massif (Cosenza), generally considered as pertaining to the metamorphic San Donato Unit. The successions start with thick phyllites and intercalated carbonate lenses containing Anisian-lower Ladinian algae. To the phyllites follows the informally defined calcari formation, locally occurring also as its lateral equivalent. The calcari formation  consists of two members, the first of which (Piano del  Minatore Mbr.)consists of black, often marly limestones, showing nodular and bioturbated textures, with a scarce and banal fauna represented by ostracods, gastropods and bivalves. Algal mounds, with porostromata and crinoids are locally intercalated in these facies. In the upper part of the formation the black limestones pass laterally to a reef complex  (Monte Caramolo Mbr.) of Ladino-Carnian age, consisting mainly of boundstones with sponges and biogenic crusts, as well as of fore-reef  breccias. These lithotypes have been interpreted as deposited on a carbonate ramp evolving to a restricted, poorly oxygenated lagoonal area, bordered by bioconstructed margins. In the lower Carnian a carbonate-marly horizon, containing traces of evaporites, whose thickness is decreasing toward the east, allows a lithostratigraphic correlation betweenmost of the studied successions. The calcari formation is followed by the Scifarello formation, mainly outcropping in the eastern parts of the studied area. It consists generally of tidal dolomites with some tempestites deposited on an shallow open  shelf, followed by dolomites and laminated, often marly, dolomitic limestones, deposited in a subtidal, restricted environment. On the basis of foraminifers and bivalves data, the upper part of the Scifarello formation has been  ascribed to the upper Carnian-Norian. Moreover, a strong tectonic activity of Lower Norian age is evidenced by the presence of mass-flows and sedimentary dikes in the more easterly areas of the massif. The general paleoenvironmental evolution, in the period spanning between Anisian and Early Norian, can be envisaged firstly in a carbonate sedimentation on a wide shelf, grading toward the east to deeper, possibly  basinal areas, whose location was controlled by the Ladinian  and/or Norian synsedimentary tectonics. This shelf was bordered on the west by a peri-continental area, with silicoclastic to evaporitic deposits, better represented in the Cetraro area. Finally, the Norian dolomites  pertaining to the Verbicaro Unit, usually considered as have been thrusted onto rhe Triassic carbonates of the San Donato Unit, have been often observed to occur in normal stratigraphical superposition over the latter. Therefore, also considering the ambiguous evidence presented in the literature on the Jurassic-Miocenic evolution of the San Donato Unit AUCT, we interpret the Norian Verbicaro dolomites as being the most natural evolution of the Anisian-Lower Norian San Donato lithotypes. It follows that for a really valid paleogeographic reconstruction a complete redefinition of the tectonic units in the whole area is needed

    The Alpujarride Triassic Platform (Internal Zones of the Betic Cordillera, Spain)

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    A partir de estudios estratigráficos, centrados en la sucesión triásica alpujárride de la Sierra de Gádor (Almería, Cordillera Bética) y su correlación con otros sectores, proponemos una columna estratigráfica sintética para la Plataforma Triásica Alpujárride. Esta columna estaría dividida en dos formaciones: una metasiliciclástica basal (subdividida en tres miembros: inferior, intermedio y superior) y una metacarbonática suprayacente (subdivididida en seis miembros, numerados del 1 al 6 de muro a techo). Esta plataforma habría sufrido una evolución morfológica en tres fases: Fase 1 de rampa homoclinal (Anisiense-Ladiniense); Fase 2 de plataforma fallada (Ladiniense-Carniense); y Fase 3 de plataforma orlada (Noriense). Además, a partir del análisis sedimentario de las asociaciones de facies reconocidas en la sucesión triásica de la Sierra de Gádor proponemos su división en cuatro secuencias deposicionales para el intervalo comprendido entre el Anisiense y el Noriense. La primera secuencia comprendería los miembros inferior e intermedio de la formación metasiliciclástica; la segunda secuencia deposicional incluiría el miembro superior de la formación metasiliciclástica y los miembros 1 y 2 de la formación metacarbonática; la tercera secuencia constaría de los miembros 3 y 4, mientras que la cuarta secuencia estaría constituida por los miembros 5 y 6.Taking into account previous detailed stratigraphic and facies analyses carried out in the Alpujarride succession from the Sierra de Gádor (Almeria province) and correlations with other sectors, we propose a synthetic stratigraphic column for the Alpujarride Triassic Platform; this column consists of two formations: a basal meta-siliciclastic formation (divided in three members, from base to top: lower, middle and upper) Anisian in age, and an overlying meta-carbonate formation (divided in six members, 1 to 6 from base to top) Anisian-Norian in age. We postulate a morphological evolution of the Alpujarride Triassic Platform including three phases: an Anisian-Ladinian homoclinal ramp first phase, a Ladinian-Carnian fault-block-type platform second phase, and a Norian rimmed platform third phase. We also divide the Anisian-Norian stratigraphic record in four depositional sequences (DS). DS1 should comprise the lower and middle members of the meta-siliciclastic formation; DS2 should be formed by the upper member of the meta-siliciclastic formation and members 1 and 2 of the meta-carbonate formation; DS3 should consist of members 3 and 4; SD4 should be composed of members 5 and 6.El presente trabajo ha sido financiado con el Proyecto de Investigación CGL2011-30153-C02-02 del Ministerio de Ciencia e Innovación, así como por el Grupo de Investigación de la Universidad de Alicante VIGROB053

    Upper Triassic platform margin biofacies and the paleogeography of Southern Apennines.

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    Upper Triassic (Norian-Rhaetian) new thalamid sponges from northern Calabria (southern Italy)

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    Two new “sphinctozoan” sponges, Calabrisiphonella labyrinthica nov. gen., nov. sp. and Calabrispongia globosa nov. gen., nov. sp., are described from reef boulders derived from Triassic dolomites (“Dolomia principale“) of the Argentino valley in Northern Calabria (Southern Italy). Calabrisiphonella is an Amblysiphonella-type sponge characterized by having a complicated canal system (labyrinth-like) within the chamber walls. The structure of Calabrispongia is similar to some Paleozoic or Jurassic Stromatoporoidea“, which are attributed to the sponges. The systemtic position of both sponges, described here, is discussed. The age of the sponge-bearing reefs represented in the boulders is Norian-Rhaetian

    Upper Triassic (Norian-Rhaetian) new thalamid sponges from northern Calabria (southern Italy)

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    Two new “sphinctozoan” sponges, Calabrisiphonella labyrinthica nov. gen., nov. sp. and Calabrispongia globosa nov. gen., nov. sp., are described from reef boulders derived from Triassic dolomites (“Dolomia principale“) of the Argentino valley in Northern Calabria (Southern Italy). Calabrisiphonella is an Amblysiphonella-type sponge characterized by having a complicated canal system (labyrinth-like) within the chamber walls. The structure of Calabrispongia is similar to some Paleozoic or Jurassic "Stromatoporoidea“, which are attributed to the sponges. The systemtic position of both sponges, described here, is discussed. The age of the sponge-bearing reefs represented in the boulders is Norian-Rhaetian
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