Giuliana Raffaelli

High-Mg Tertiary basalts in Southern Sardinia (Italy)

Abstract High-Mg basaltic pillow lavas, important for an understanding of the petrogenetic evolution of the Tertiary volcanism of Sardinia, have recently been recognized in the lower part of the Early-Burdigalian volcano-sedimentary succession of the Villanovaforru (VF) area (Southern Sardinian Trough). Their textures vary from porphyritic to highly phyric types (doleritic) and the paragenesis is represented by Pl+Ol+Cpx±Opx±Opq. These basalts are sub-alkaline with a tholeiitic tendency; they display high MgO (mg-number 64–68), high Ni and Cr contents and their geochemical features are related to subduction-related magmas, with large-ion lithophile element enrichment and negative Nb, Zr and Ce spikes in mantle-normalized diagrams. The mineralogical and geochemical characteristics indicate that the VF basalts crystallized from primitive magmas within an extension-dominated tectonic setting. The presence of primitive basalts suggests crustal thinning in association with the Burdigalian extensional tectonics affecting the Sardinian Trough.

New data on the Vrancea Nappe (Moldavidian Basin, Outer Carpathian Domain, Romania): paleogeographic and geodynamic reconstructions

A study has been performed on the Cretaceous to Early Miocene succession of the Vrancea Nappe (Outer Carpathians, Romania), based on field reconstruction of the stratigraphic record, mineralogical-petrographic and geochemical analyses. Extra-basinal clastic supply and intra-basinal autochthonous deposits have been differentiated, appearing laterally inter-fingered and/or interbedded. The main clastic petrofacies consist of calcarenites, sub-litharenites, quartzarenites, sub-arkoses, and polygenic conglomerates derived from extra-basinal margins. An alternate internal and external provenance of the different supplies is the result of the paleogeographic re-organization of the basin/margins system due to tectonic activation and exhumation of rising areas. The intra-basinal deposits consist of black shales and siliceous sediments (silexites and cherty beds), evidencing major environmental changes in the Moldavidian Basin. Organic-matter-rich black shales were deposited during anoxic episodes related to sediment starvation and high nutrient influx due to paleogeographic isolation of the basin caused by plate drifting. The black shales display relatively high contents in sub-mature to mature, Type II lipidic organic matter (good oil and gas-prone source rocks) constituting a potentially active petroleum system. The intra-basinal siliceous sediments are related to oxic pelagic or hemipelagic environments under tectonic quiescence conditions although its increase in the Oligocene part of the succession can be correlated with volcanic supplies. The integration of all the data in the “progressive reorientation of convergence direction” Carpathian model, and their consideration in the framework of a foreland basin, led to propose some constrains on the paleogeographic-geodynamic evolutionary model of the Moldavidian Basin from the Late Cretaceous to the Burdigalian.

Geological risk assessment of Amtoudi Agadir in southern Morocco: a key case for sustainable cultural heritage

Abstract Medieval fortified granaries known as “agadirs” are very common in southern Morocco, being catalogued as world cultural heritage by United Nations. These Berber buildings (made of stones and tree trunks) usually located on rocky promontories, constitute historical testimonials related to the origin of Morocco, and, as tourist attractions, have a positive impact on the local economy. The sustainability of these ancient monuments requires geological-risk evaluations of the massif stability under the agadir with the proposal of stabilization measures, and an architectonic analysis with appropriate maintenance of the structural elements. An interdisciplinary study including climate, seismicity, hydrology, geology, geomorphology, geotechnical surveys of the massif, and diagnosis of the degradation of structural elements have been performed on the Amtoudi Agadir, selected as a case study. The main findings from this study are that the prevalent rocks used for construction (coming from the underlying substratum) are good-quality arkosic sandstones; the SW cliffs under the agadir are unstable under water saturation; some masonry walls are too thin and lack interlocking stones and mortar; and failures in the beams (due to flexure, fracture, and exhaustion in the resistance due to insect attacks or plant roots) are common. The basic risk assessment of ancient buildings of cultural heritage and their geologic substratum are needed especially in undeveloped areas with limited capacity to implement durable conservation policies. Therefore, recommendations have been provided to ensure the stability and maintenance of this important archaeological site.

Archaeometric study of a typical medieval fortified granary (Amtoudi Agadir, Anti-Atlas Chain, southern Morocco): a key case for the maintenance and restoration of historical monuments

This research was supported by Urbino University found (Resp. F. Guerrera); by CGL2011-30153-CO2-02 and CGL2012-32169 research project (Spanish Ministry of Education and Science) and by Research Groups and projects of the “Generalitat Valenciana” from Alicante University (CTMA-IGA).

The External Tanger Unit (Intrarif sub-Domain, External Rifian Zones, Morocco): an interdisciplinary study

The External Tanger Unit represents one of the most complete Cretaceous-Miocene successions in the central areas of the Internal Intrarif sub-Domain (External Rif Zones, Morocco). An interdisciplinary study has been carried out to propose a new characterization of this unit which would allow a better comprehension of the confused and complex relationships among different units of the same sub-domain. The results achieved can be summarized as follows: (1) redefinition of the stratigraphic (litho-, bio-, and chrono-) record and introduction of a new, informal lithostratigraphic terminology; (2) recognition of two main depositional sequences (lower-middle Eocene p.p. and lower Oligocene p.p.-lower Miocene p.p.) separated by extended gaps (latest Cretaceous-early Eocene p.p. and middle Eocene p.p.-early Oligocene p.p.); (3) reconstruction of the evolution of the sedimentary realm, and of the relationships between tectonics and sedimentation; and (4) comparison between the upper Cretaceous-Miocene stratigraphic record and tectonic events of the Intrarif, which is located in the western external portion of the Maghrebian Flysch Basin, and the equivalent sedimentary record of the eastern portion of this basin in the Tunisian Tell. More in general, our results allowed (i) a first reconstruction of the Cretaceous-Miocene main tectono-sedimentary events; (ii) a more detailed location of the sedimentary suite in the external African Margin in the context of a wider palaeogeographic framework; and (iii) the definition of the main stages of the geological evolution of the area.

Miocene tectono-sedimentary evolution of the eastern external Betic Cordillera (Spain)

ABSTRACT An interdisciplinary study of Miocene successions in the eastern External Betic Zone (South Iberian Margin) was carried out. Evidences of syn-sedimentary tectonic activity were recognized. The results enabled a better reconstruction of the stratigraphic architecture (with an improved chronostratigraphic resolution) in the framework of the Miocene foredeep evolution of the eastern EBZ. Two main depositional sequences were dated as uppermost Burdigalian-upper Serravallian p.p. and middle-upper Tortonian. p.p., respectively. The vertical and lateral diversification of lithofacies associations and thicknesses resulted from the syn-depositional tectonic complexity of the area. A great variety of sedimentary depositional realms is due to different subsidence rates, and the growing of anticlines and synclines during the Langhian p.p.-Serravallian. After a regression with an early Tortonian erosional gap, platform to hemipelagic realms developed during the middle Tortonian. The end of the sedimentation coincided with the emplacement of an important olisthostrome-like mass consisting of Triassic material related to either the development of thrust systems or diapirs emerged in the middle-late Tortonian, during the nappe emplacement. Correlations with other external sectors of the Betic Chain, and the external domains of the Rif, Tell, and northern Apennine Chains highlighted a similar Miocene foredeep evolution during the building of these orogens.

The facade of the church of Saint Spirit in Urbino: from scientific investigations to restoration

The state of advanced deterioration of the church of Saint Spirito of Urbino has induced the Superintendence for the Historical Artistic and Demoetnoanthropological Heritage of the Marches-Urbino and the Archiepiscopal Curia to program an intervention of restoration. Before that, the facade was covered from black crusts, grey deposits and yellowish films. The bricks of the wall, until to a height of approximately three meters from the bottom, moreover they were interested from processes of detachment, disintegration and exfoliation. In such area the presence of humidity was rather obvious and was attributable to phenomena of rising dump. In order to identify the constituent materials and to estimate of the state of conservation they have been carry out scientific investigations, whose it turns out have supplied profits indications for the restoration.