Central Apennines Italy Research Articles

The role of deformation bands, stylolites and sheared stylolites in fault development in carbonate grainstones of Majella Mountain, Italy

In this paper we document deformation processes in porous carbonate grainstones of Cretaceous age in Majella Mountain in the central Apennines of Italy by detailed mapping of meso- and microstructural features as well as thin section observations and image analyses. We distinguished three main deformation mechanisms: (i) deformation bands developed by compaction and shear strain localization, (ii) stylolites formed by pressure solution, and (iii) subsequent shearing of stylolites. The deformation bands occur in six sets: five sets are compactive shear bands at high angles to bedding and one, which is the oldest, occurs parallel to bedding and is interpreted to be a compaction band. Stylolites localize along and within all six sets of deformation bands and are commonly sheared, as evidenced by striated surfaces and detectable offsets. These sheared stylolites are in many cases associated with one or two sets of subsidiary stylolites, oblique to the major set. The band-parallel sheared stylolites, together with the associated oblique sets of stylolites, form a tabular zone of fine grained cataclastic material within the compactive shear bands and accommodate slip in the range of 5–75 cm. The bed-parallel compaction bands and bed-parallel stylolites, which are kinematically compatible, are interpreted to be pre-tilting structures developed in response to the overburden, whereas the five sets of compactive shear bands and the associated stylolites and sheared stylolites likely occurred during the syn- and post-tilting deformation phases recorded in the Majella anticline.

Tree-ring growth of silver fir ( Abies alba Mill.) in two stands under different silvicultural systems in central Italy

A preliminary analysis was made of growth trends in two silver fir forests in the Apennines in central Italy. The forests are closely located but were managed differently in the past. The aim was to verify the climatic variation over time, the influence of extreme events on radial growth and the role of silvicultural systems in defining growth response. The two forests have distinct structures due to differing past silvicultural management. The Camaldoli Forest, containing one-storeyed, evenaged, pure silver fir stands, was essentially managed in the past for wood production and featured high plantation density, low to moderate thinning, and clear cutting every 80–100 years. The La Verna Forest includes multi-layered, unevenaged stands that are mixed in with beech and other broadleaves. Increment cores were collected from aged dominant and healthy trees in the two forests. Climatic data were taken from the Camaldoli station and covers the period 1885–1994. All the analysed dendroecological parameters displayed similar patterns and indicated suitable site conditions for the silver fir. Silvicultural systems played an important role in defining growth pattern and rate. In the evenaged system there were higher growth rates and a greater number of pointer years, whereas there were lower growth rates and long, homogeneous development stages in the semi-natural conditions of La Verna. A rising growth trend recorded in the last three decades in both series could be explained by the consistent extension of the growing season due to a significant increase of mean spring and autumn temperatures. No correlation was found with precipitation while significant correlations were found between tree ring growth and February, April and August temperatures. Preliminary results indicated that the silvicultural system does not bias, but just enhances the ability of the species to record the effects of disturbing factors.

COMMENT ON MELLUSO ET AL. (2003): Reported data and interpretation of some wollastonite- and melilite-bearing rocks from the Central Apennines of Italy

Two distinct occurrences of wollastonite- and melilite-bearing rocks from Ricetto and Colle Fabbri, which are located in the central Italy Apennine Range, are referred to as “paralavas” generated by melting and recrystallization of marly sediments “likely due to coal fires” by Melluso et al. (2003). We submit data demonstrating that these conclusions are incorrect. Ricetto is clearly pyrometamorphic, as described by Capitanio et al. (2001, 2004). Colle Fabbri is clearly an igneous outcrop as described in Stoppa (1988). It is quite different in scale, field relationships, and chemistry, and thus Ricetto is irrelevant to its petrogenesis. The sediment mixing model of Melluso et al. (2003) does not relate to the Colle Fabbri field data. Furthermore, the Ricetto Miocene flysch country-rock and the Colle Fabbri enclosing Pliocene clays were not analyzed by Melluso et al. (2003). A limestone-shale mixing calculation using Sr and Nd isotopic data in Melluso et al. (2003, Tables 3.4) and a 143 Nd/ 144 Nd ratio of 0.51213 for Apennine shales (op.cit. p. 1297) fails to account for the Colle Fabbri samples, which remain well clear of the hypothetical mixing line. Rocks of mantle origin, including micaceous kimberlites and Western Australia lamproites, plot in the variation field of Colle Fabbri and regionally associated igneous rocks. Colle Fabbri is but one of a series of similar igneous melilite-bearing and carbonatite occurrences that constitute the Intramontane Ultra-alkaline Province of central Italy (IUP), although Colle Fabbri does have unique features, as do other of these occurrences (Stoppa et al. 2003).

From a deformed Peri-Tethyan carbonate platform to a fold-and-thrust-belt: an example from the Central Apennines (Italy)

In the Central Apennines of Italy, the relationships between the foreland deformation of a Peri-Tethyan carbonate platform (Lazio–Abruzzi domain) and the subsequent contractional pattern have been clearly documented by means of stratigraphic and structural evidence. Stratigraphic and structural data point out the occurrence of pre-thrusting normal fault systems, and allow us to define their relationships with contractional structures. Miocene normal faults are particularly well documented by thickness and facies variation of foredeep deposits and by structural evidence. These faults controlled sedimentation during Tortonian–Early Messinian times (foredeep stage), and produced most of the accommodation space for clastic deposits in their hanging-walls. On the contrary, the subsequent positive inversion appears to be quite limited, and generally the hanging-wall sequences are not uplifted above the regional. Clear evidence that normal faults formed first and were later cut and/or rotated during thrusting is supported by analyses carried out along the main fault surfaces. The restoration of a balanced geological section across the study area, based on the inference of an extended foreland affected by later contraction, provided a total, small shortening value. This is lower than the previous estimated by several authors, for the same foreland-fold-and-thrust-belt.

Defining a model of 3D seismogenic sources for Seismic Hazard Assessment applications: The case of central Apennines (Italy)

Geology-based methods for Probabilistic Seismic Hazard Assessment (PSHA) have been developing in Italy. These methods require information on the geometric, kinematic and energetic parameters of the major seismogenic faults. In this paper, we define a model of 3D seismogenic sources in the central Apennines of Italy. Our approach is mainly structural-seismotectonic: we integrate surface geology data (trace of active faults, i.e. 2D features) with seismicity and subsurface geological–geophysical data (3D approach). A fundamental step is to fix constraints on the thickness of the seismogenic layer and deep geometry of faults: we use constraints from the depth distribution of aftershock zones and background seismicity; we also use information on the structural style of the extensional deformation at crustal scale (mainly from seismic reflection data), as well as on the strength and behaviour (brittle versus plastic) of the crust by rheological profiling. Geological observations allow us to define a segmentation model consisting of major fault structures separated by first-order (kilometric scale) structural-geometric complexities considered as likely barriers to the propagation of major earthquake ruptures. Once defined the 3D fault features and the segmentation model, the step onward is the computation of the maximum magnitude of the expected earthquake (Mmax). We compare three different estimates of Mmax: (1) from association of past earthquakes to faults; (2) from 3D fault geometry and (3) from geometrical estimate ‘corrected’ by earthquake scaling laws. By integrating all the data, we define a model of seismogenic sources (seismogenic boxes), which can be directly used for regional-scale PSHA. Preliminary applications of PSHA indicate that the 3D approach may allow to hazard scenarios more realistic than those previously proposed.

Orbitolinidae and Alveolinidae (Foraminiferida) from the uppermost Albian-lower Cenomanian of Monti d'Ocre (Abruzzi, Italy)

A biostratigraphic study carried out in the Monti d'Ocre area, Abruzzi, Central Apennines, allowed us to recognize Orbitolina ( Conicorbitolina) moulladei ‘Strata 5 (1985) 1’, Praealveolina iberica Reichel and Praealveolina simplex Reichel in uppermost Albian–lower Cenomanian shelf-edge deposits of the Fossato Machè succession. These foraminifers have now been found for the first time in the Apennines of central Italy; their finding is quite important from a palaeobiogeographic viewpoint, as it contributes to the improvement of our knowledge on facies distribution in the circum-Mediterranean regions during the Cretaceous Period. In the study area, the coeval Monte Rotondo and Monte Orsello sections also crop out; these are characterized by bauxite deposits and stratigraphic gaps reflecting episodes of emergence on the carbonate platform. The Monte Rotondo and Monte Orsello sections accumulated in a platform back-reef environment; consequently, in this sector of the Monti d'Ocre area, the depositional environment shifted from a back-reef westward and southward to a shelf-edge northward, during the latest Albian–early Cenomanian. Owing to synsedimentary tectonics, the area investigated underwent differential subsidence: westward and southward, wide areas were uplifted and subjected to emergence, karstification and bauxite accumulation, whereas sedimentation continued in a shelf-edge environment in the north-eastern area.

Application of multivariate analysis for recognition of organic patinas on stone monuments

Black organic films, which had accumulated over ages on stone monuments in ancient villages located in the Apennines in central Italy, were solvent-extracted and the extracts analyzed by capillary gas chromatography. The overall procedure, selection of the monuments and patina extraction followed by chromatographic analysis and processing of the data, was developed with the purpose of establishing a new methodology for clusterization of ancient monuments located in the same geographic area, or even of different parts of the same monument, according to the chemical substances deposited on their surfaces. This concept relies on the assumption that the black crusts present on the monument surface represent a chemical memory of the work of art itself, related to its history, topological location, and exposure to environmental conditions. Selection of the most appropriate extraction solvent, as well as treatment of the chromatographic data, was carried out with the aid of multivariate chemometric methods to obtain classification models.

Application of multivariate analysis for recognition of organic patinas on stone monuments

Black organic films, which had accumulated over ages on stone monuments in ancient villages located in the Apennines in central Italy, were solvent-extracted and the extracts analyzed by capillary gas chromatography. The overall procedure, selection of the monuments and patina extraction followed by chromatographic analysis and processing of the data, was developed with the purpose of establishing a new methodology for clusterization of ancient monuments located in the same geographic area, or even of different parts of the same monument, according to the chemical substances deposited on their surfaces. This concept relies on the assumption that the black crusts present on the monument surface represent a chemical memory of the work of art itself, related to its history, topological location, and exposure to environmental conditions. Selection of the most appropriate extraction solvent, as well as treatment of the chromatographic data, was carried out with the aid of multivariate chemometric methods to obtain classification models.

Interactions between mantle upwelling, drainage evolution and active normal faulting: an example from the central Apennines (Italy)

In this paper we show that the processes that have shaped the Quaternary surface development of the Apennines in central Italy are all consequences of a single subcrustal process, the upwelling of the mantle. The relationship between gravity and topography shows that mantle convection is responsible for a long-wavelength (150–200km) topographic bulge over the central Apennines, and stratigraphic evidence suggests this bulge developed in the Quaternary. Active normal faulting is localized at the crest of this bulge and produces internally-draining fault-bounded basins. These basins have been progressively captured by the aggressive headward erosion of major streams that cut down to the sea on the flanks of the regional bulge. The only surviving closed basins are those on the Apennine watershed most distant from the marine base level, where continued normal faulting is still able to provide local subsidence that defeats their capture by the regional drainage network. Understanding the competition between regional capture and local, fault-related subsidence of intermontane basins is crucial for recognizing potentially hazardous active faults in the landscape and also for interpreting the sediment supply to adjacent offshore regions. Central Italy provides a good modern analogue for processes that are probably common in the geological record, particularly on rifted margins and intracontinental rifts, but may not have been fully appreciated.

Impact of tourism on the mountain landscape of central Italy

The mountain landscape of the Apennines in central Italy has been severly affected by tourism for decades. Field research was carried out in order to investigate if some general patterns of environmental changes could be detected. The vegetation of several places under ski-lifts was analysed on the basis of a careful floral survey. In all cases a strong decline of the floristic diversity was observed. On the lines of frequent transit, numbers of occurring species became reduced to about one half and species resistant to trampling (eventually present outside of the ski-lift trucks) expanded and became dominant. The parallel investigation of impacts on human artefacts dealt with architectural features of Leonessa town, a typical example of traditional architecture built at the end of the Middle Ages. Number, size and shape of windows and gates was studied. A comparison was made with the architecture of a modern tourist resort. The recent constructions appear to be characterized by dominance of few elements, general uniformity and normalization. From both examples it can be concluded that the undisturbed condition is in a state of high diversity which declines under the effects of heavy human impact.

Debris-flow phenomena in the Central Apennines of Italy : Guzzetti, F; Cardinali, M Terra NovaV3, N6, 1991, P619–627

Debris-flow phenomena in the Central Apennines of Italy : Guzzetti, F; Cardinali, M Terra NovaV3, N6, 1991, P619–627

Debris‐flow phenomena in the Central Apennines of Italy

ABSTRACTThe results of a research project on the extent of debris‐flow processes in the Monti Sibillini area (Central Italy) are presented. Debris flows have greatly contributed in shaping the landscape of the Monti Sibillini territory. Based on the dominant active process they can be subdivided into three sections: a source area, a transport area and a depositional area. Four environments can be identified as source areas: landslide deposits, highly fractured rocks, scree or talus deposits, and glacial deposits. The evolution of some of the largest features present in the area is examined. These may have developed from an initial stage of mostly gully erosion and minor landsliding, through an intermediate stage characterized by extensive mass‐movement, to a final stage dominated by fluvial processes. Lastly, generalizations on the debris‐flow hazard in the study area are made.

Cyclic geomagnetic changes in Mid‐Cretaceous rhythmites, Italy

ABSTRACTMagnetic secular variation is recorded as a quasi‐rhythmical process of uncertain origin. Rhythmic changes recorded in the Scisti a Fucoidi in the central Apennines of Italy, pelagic sediments of Mid‐Cretaceous (Late Albian) age, show strong correspondence to patterns of orbital variation. In the same strata cyclic magnetic variations are found with peaks in the same range (105, 40, 26,19 kyr). These results appear to support earlier suggestions that secular variations may be related to these astronomical patterns.

Measured and simulated water relations in a Douglas-Fir forest during the development of drought in the Apennines, Central Italy

A model of soil water dynamics (SWATRE) and of the soil-plant-atmosphere continuum (SPAC), including the plant water-retention component, were applied independently to describe the seasonal and diurnal water balance of a forest in Italy. The stand under consideration was a 26-year-old Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) plantation with a density of 2044 trees ha −1 and average height of 14.2 m, located in the Apennines in Central Italy, 900 m a.s.l, in a mediterranean climate. Soil water potential was measured with tensiometers and psychrometers 2 or 3 times per week during the summer of 1985. The xylem water potential and leaf stomatal conductance were measured on 4 days in the period June–September 1985, at about 2–3 h intervals from sunrise to sunset. Global and net solar radiation, air temperature and air relative humidity above the canopy were measured. Soil water potentials simulated by the SWATRE model agreed well with the field measurements. The diurnal pattern of bulk stomatal resistance and xylem water potential simulated by the SPAC model also agreed with measurements. The results show that Douglas-fir is surprisingly well adapted to the drought conditions that occurred in Tuscany during the dry year 1985, and even with dry soil, shallow rooting depth and high evaporative demand, trees did not show evident water stress.

Les formations de la limite Jurassique-Crétacé en Tunisie septentrionale (Djebel Oust). Série lithologique; résultats biostratigraphiques et paléogéographiques d'après les Ammonites, les Calpionelles et les Ostracodes

A stratigraphic research concerning Tithonic-Berriasian beds in northern Tunisia (Djebel Oust) points out that here, as in some parts of Algeria, the Inferior Cretaceous detritic phase begins in the Berriasian. A gradually deepening of the sea is noted from Inferior Tithonic till Middle Berriasian, with bathyal to hemipelagic facies, and submarine slidings. There are close similarities in ostracodal associations with Monts de Batna in Algeria, and some affinities are observed with the central Apennines in Italy.