Plio-Quaternary geological evolution of the high Salto River Valley (Central Italy): the Marano De’ Marsi Unit

This paper summarizes the results of multidisciplinary researches carried out in a wide span of time on the earliest continental deposits of the high Salto River valley. The study led us to characterize sedimentary environments, to analyze their relationships and to propose a chronological attribution. Facies are referable to a complex depositional system consisting of a Gilbert-type lacustrine delta and of slope-type partly interfingered fan deltas coming from the eastern border of the basin. The geological data collected allowed us to refer the succession to a single sedimentary cycle; in Marano de’ Marsi area the paleodrainage and progradation directions were also recognized. To better constrain the chronological, paleoclimatic and paleoenvironmental context, detailed investigations have been conducted on pelitic facies of the deltaic-lacustrine system in two sampling sites (an artificial outcrop at Marano de’ Marsi village and a borehole near Borgorose village). Paleomagnetic analyses show that Marano de’ Marsi and Borgorose successions have a normal polarity and generally low magnetic susceptibility values. Pollen diagrams from both sites mainly record a mid to high elevation forest pollen rain. The existence of trees from different vegetation belts suggests the presence of a well developed mountain system in the surroundings. In the case of Marano de’ Marsi section, these vegetation phases alternate with sudden, strong and short spreads of temperate and subtropical taxa. These alternations suggest that important climate changes occurred, with cyclical forest variations typical of glacial / interglacial periods of Pliocene and Early Pleistocene. Pollen and paleomagnetic data led us to refer both records to the Olduvai subchron, at the end of the Pliocene; nevertheless, the possibility that the records deposited during the Gauss chron cannot be, definitely, excluded. Field geological data and magnetic fabric results suggest that the Marano de’ Marsi unit sedimentation took place in a basin developed under extensional tectonic regime

Pollen and macrofossil analyses of Pliocene lacustrine sediments (Salto river valley, Central Italy)

The study of two sedimentary records sampled in the fluvio-lacustrine succession of high Salto river valley (Rieti, central Italy) was originated in the frame of the Geomorphologic Map of Italy (APAT, 2008) field survey and improved with a multidisciplinary approach addressed to a better knowledge of the Plio- Pleistocene continental environments of central Apennines. The two successions are associated to different sedimentary facies, with lateral heteropic relations: the deposits cropping out at Marano de’ Marsi are thought to represent deposition in the distal portion of a lacustrine delta, while those of Borgorose took place in a frankly lacustrine environment. The sediment succession from Marano de’ Marsi (11 m) was sampled from an outcrop, the one from Borgorose (24.5 m) from a drillhole. Palaeomagnetic investigations carried out on both sediment records indicate a normal magnetic polarity and very low magnetic susceptibility values. In the record from Marano de’ Marsi section, gymnosperm pollen is prevailing. Four main and short angiosperm arboreal pollen oscillations can however be observed, the oldest of which more marked. The gymnosperms are mainly represented by Pinus haploxylon type, Pinus sylvestris type, Cedrus, Picea, Abies, Cathaya, Tsuga, Taxodium type. Among angiosperms the dominant taxa, some of which at present extinct in Italy, are Quercus, Zelkova, Ulmus, Carya and Pterocarya. The presence of pollen of subtropical taxa as Nyssa, cfr. Rhoiptelea, Liquidambar, Engelhardia is worth to be mentioned. The investigation was integrated also by a preliminary study of macrofossils. Fossil impressions with some organic matter of angiosperm and gymnosperm leaves and seeds/fruits were ascribed to Acer cfr. monspessulanum, Carpinus cfr. orientalis, Engelhardia, Fagus, Hedera, Liquidambar, Quercus, Rosa, Abies and Pinus. The 24.5 m long sediment core from Borgorose resulted very poor in pollen, with the same list of arboreal taxa, at present extinct in Italy, found at Marano de’ Marsi, and a diagramwas drawn only for the stretch of the core between 3 and 8.2 m. Gymnosperms (P. haploxylon type is dominant, and accompanied by P. sylvestris type, Picea, Taxodium type, Cedrus, and Tsuga) are always prevailing. The results obtained by this interdisciplinary investigation indicate that Marano de’ Marsi and Borgorose successions can be possibly attributed to the Upper Pliocene (normal polarity Olduvai subchron) even if an older age, considering the present state of the art on Pliocene continental records, and the peculiarity of the site and of the region, cannot be excluded

Traces of the active Capitignano and San Giovanni faults (Abruzzi Apennines, Italy)

We present a 1:20,000 scale map of the traces of the active Capitignano and San Giovanni faults in the area of the Montereale basin (central Apennines, Italy) covering an area of about 80 km2. Detailed fault mapping is based on high-resolution topography from airborne LiDAR imagery validated by extensive ground truthing and geophysical prospecting. Our analysis allowed the recognition of several features related to fault activity, even in scarcely accessible areas characterized by dense vegetation cover and rugged terrain. The identified fault traces run at the base of the NW-SE striking Montereale basin-bounding mountain front and along the base of the southwestern slope of the Monte Mozzano ridge, and have a length of about 12 and 8 km, respectively. Improving the knowledge of fault geometry is a critical issue not only for the recognition of seismogenic sources but also for surface fault hazard assessment and for local urban planning. The knowledge of the exact location of the fault traces is also crucial for the seismogenic characterization of the active faults by means of paleoseismological trenching.‘FIRB Abruzzo – High-resolution analyses for assessing the seismic hazard and risk of the areas affected by the 6 April 2009 earthquake’, ref. RBAP10ZC8K_005Published453-4592T. Tettonica attivaJCR Journalreserve

Toward an update of the structural model in Italian submerged areas: contributions from the EMODnet Geology Project

The European Marine Observation and Data Network (EMODNet) Project aims at the collection of as many existing data as possible on European Seas to be represented on digital maps at the 1:250,000 scale, accessible via web through a dedicated portal. It is articulated into different Lots concerning Bathymetry, Geology, Biology, Chemistry, Physics, Physical Habitats, Human activities. The Geology Lot is realized by a Consortium in which the Geological Survey of Italy is partner. EMODnet Geology requires the compilation of a number of layers subdivided into Work Packages (WP), referring to seafloor sediments grainsize, sedimentation rates, Quaternary geology, pre-Quaternary geology and stratigraphy, coastal behavior, geological events (earthquakes, volcanoes, landslides), mineral resources. The Geological Survey of Italy is WP Leader for geological events and, in agreement with other partners, has included tsunamis, tectonics and fluid emissions among the features to be represented. The compilation of several layers (particularly tectonics and volcanoes) suggested the possibility, based on the wealth of data acquired in the last decades and the significant improvement in instrument resolution achieved, to elaborate an updated structural model for the Italian submerged areas, in agreement with the model established on land. Data represented in the last published version of the structural model (CNR - Structural model of Italy, 1983) have been updated and implemented by data and results obtained in the frame of the ongoing Italian National Geological Mapping Project (CARG), as well as by additional data collected by different national research institutions within other projects. The integration of all available tectonic lineaments with the outcomes elaborated for EMODnet-Geology (such as the map of submarine volcanoes) has led to the identification of the structural elements that represent the basic components for an updated and more complete structural model