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Palaeopelagos, Spec. Publ.n.3

Two hypercalcified sphinctozoan sponges are described from several localities of dolomitic Norian reefs of northern Calabria (southern Italy). Solenolmia? parva n. sp. occurs as an extremely abundant, albeit local, component in peculiar bioconstructions dominated by serpulids and microbialitic crusts. Discosiphonella minima Senowbari-Daryan & Link, previously recognized only in the type locality of Turkey, has been now found also as a minor component in association with other typical "Dachstein" reef biota, such as corals, sponges, microbial crusts and fragments of "microproblematica". Solenolmia? parva assemblage represents the primary framebuilder of small build-ups which developed on the margins of restricted intraplatform basins. The Discosiphonella minima assemblages were found as resedimented blocks along the slope of intraplatform anoxic basins. The distribution of the different reefal assemblages of Northern Calabria can be related to the paleogeographic position of northern Calabria with respect to the evolution of Triassic crustal extension in western Mediterranean.

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., Rivista Italiana di Paleontologia e Stratigrafia (Research In Paleontology and Stratigraphy), V. 101, N. 3

Norian-Rhaetian platfom margin buildups in Southern Apennines are mainly characterised by microbial-serpulid communities. However, the existence of marginal settings with metazoan-dominated buildups can be documented in several localities. The Jurassic fate of Rhaetian buildups was largely decided by the end-Triassic biological crisis that affected both the metazoan reefs and the microbial ones. Deep-water conditions persisted in the intraplatform troughs during the whole Lower Jurassic and locally also in the Middle Jurassic. The successions belonging to the Bulgheria and Verbicaro Units show basinal or slope facies during the whole Mesozoic, with a short shallowing-upward trend around the Triassic-Jurassic transition. The successions of western Matese-Mt. Marzano group-Maddalena Mts. record a more evident Hettangian regressive trend, followed by a transgressive trend starting from the base of the P. mediterraneus zone. At present it is not possible to assess the influence of eustatic vs. tectonic control on this sedimentary evolution.

Very few data are available on the facies characters and geometric relations at the carbonate platform-to-basin transition in the Southern Apennines thrust belt. In this paper we describe an Early Jurassic submarine scarp exposed on the southern slope of Monte Capello, in the NW Matese Mountains. The paleo-scarp is cut into a Rhaetian-Lower Jurassic lagoonal to peritidal carbonate succession and is fossilized by coarse carbonate resediments with minor background hemipelagites. The contact between the slope facies and the platform limestones is a very irregular concave-upward surface. The scalloped geometry of the platform escarpment and the textures of the breccias point to local collapses along a steep submarine slope. The composition of the breccias and their contact with inner platform facies suggest that there was a considerable erosional retreat of the platform margin. Extensional faults, probably located at the platform-to-basin transition, triggered the sediment gravity flows responsible of the erosional retreat of the platform edge either directly, by fault-induced seismic shocks, or indirectly by oversteepening. This conclusion is consistent with published data indicating that Early Jurassic tectonics is a common feature in Southern Apennines as well as in Sicily, Northern Apennines and Southern Alps.