Northern-central Apennines Research Articles

Twenty-Seven Y-Chromosome Short Tandem Repeats Analysis of Italian Mummies of the 16th and 18th Centuries: An Interdisciplinary Research.

Roccapelago (MO) is a small village located in the Northern Central Apennines, with a population of 31 inhabitants (2014). In 2010, more than 400 individuals dated between the end of the 16th and the 18th century, many of which partially mummified, were discovered in the crypt of the church. This small village, because of its geographical location and surrounding environment, seems to possess the characteristics of a genetic isolate, useful for population genetics and genealogical analyses. Thus, a diachronic study of DNA aimed at investigating the structure and dynamics of the population of Roccapelago over the about 4 centuries, was conducted by analyzing ancient and modern inhabitants of the village. The 14 modern samples were selected by considering both the founder surnames of the village, identified thanks to the study of parish registers, and the grandparent’s criterion. From 25 ancient mummies, morphologically assigned to male individuals, the petrous bone, that harbors high DNA amounts, was selected for the DNA extraction. The quantification and qualitative assessment of total human male DNA were evaluated by a real-time PCR assay using the Quantifiler Trio DNA Quantification Kit and multiplex PCR of 27 Y-chromosome short tandem repeat (Y-STR) markers included in the Yfiler Plus PCR Amplification Kit, with seven rapidly mutating Y-STR loci for improving discrimination of male lineages, was performed to genotype the samples. Y-STRs were analyzed according to the criteria of ancient DNA (aDNA) analysis to ensure that authentic DNA typing results were obtained from these ancient samples. The molecular analysis showed the usefulness of the Y chromosome to identify historically relevant remains and discover patterns of relatedness in communities moving from anthropology to genetic genealogy and forensics.

An alternative model for the recent evolution of the Northern–Central Apennines (Italy)

The aim of this paper is to propose an alternative model for the Pliocene-Quaternary to present evolution of the Northern–Central Apennines by combining geometrical requirements (Riedel shear system) with existing structural and geological geometries (fault systems and their tectonic associations). We define three sectors characterized by different geological, seismological, geodetic and geothermal signatures: the North-Western Sector (NWS), the Western Central Sector (WCS) and the Eastern Central Sector (ECS). According to GPS data derived from literature the three blocks move independently. In particular, the NWS is bound between the ECS/WCS and the Alps; this constraint leads to a stress accumulation responsible for a fragmentation into further several blocks, which move either to the NE or SW. The WCS is relatively stable; the ECS moves towards NE and is characterized by the presence of numerous releasing and restraining bends, which can be related to the action of a main NNW–SSE left-lateral shear zone. Accordingly, the recent and active tectonic setting of the Northern–Central Apennines is rather related to the dynamics of the introduced blocks, caused by the push of the African plate against Europe, than to subduction processes.

Strike-slip geometry inferred from the seismicity of the Northern-Central Apennines (Italy)

The aim of this paper is to draw attention to the real number and distribution of strike-slip earthquake focal mechanisms that are displayed in the recent seismicity of the Northern-Central Apennines. Their relation to the superficial normal fault plane solutions and thrust front along the Eastern side of the Apenninic chain can be described by a geometrical model (Riedel-System, also Riedel shear model). First we define three sectors characterized by their different seismological signatures: the North-Western Sector (NWS), the Western Central Sector (WCS) and the Eastern Central Sector (ECS). These three blocks, according to the available data, act independently from each other as a consequence of interaction among themselves, the forces induced by plate tectonics in the Mediterranean area and the blocking effect of the Alpine Chain, leading to an increased amount of transpressional, pure strike-slip and transtensional tectonics below 10 km depth.

Seismicity and deep structure of the northern-central Apennines

Seismicity and deep structure of the northern-central Apennines

Geometry and kinematics of Triassic-to-Recent structures in the Northern-Central Apennines: a review and an original working hypothesis

The geological evolution of the Northern-Central Apennines has been strongly controlled by structural features inherited from pre-thrusting stages. The Apennines consist of a fold-and-thrust belt developed during Neogene time, involving sedimentary successions that were deposited within different paleogeographic domains. The paleogeographic evolution was controlled by the effects of syn-sedimentary tectonics that were active in the Triassic-Neogene time interval, and that are, from Trias to Neogene, related to different geodynamic settings. The Jurassic extensional phase favoured the dissecting of the Triassic carbonate platform and led to the development of different paleogeographic domains. Main oblique and trasversal faults, with transtensive kinematics, characterized the boundaries between different domains. After the Jurassic phase, from Cretaceous to Neogene, the Northern-Central Apennines were characterized by the development of ridges and depressions. These structures were affected by the development of normal fault systems, bending processes within the ridges, with uplift of the crestal sectors and tilting in the peripheripheral ones. The geometries and the structural setting of the foreland domains, of the foredeep and piggy back basins and of the Neogene Apenninic thrust belt are controlled by evolution of the former tectonic elements evolution. The development of extensional faults, the uplift and bending observed in the Apenninic sedimentary sequences during the convergence phase and during a part of the continental collision phase could represent distal effect of the dominant compressional regime. In this geodynamic domain the first tectonic inversion processes in a positive sense occurred along the pre-existing Jurassic listric faults systems. The reactivation first affected the flat sectors of the fault planes and then progressively more superficial ones. In the upper sedimentary cover these processes favoured buckling, flexuring and faulting. Furthermore, during the subsequent involvement of the foreland domains in the foredeep and chain systems, the propagating thrust surface still reused former discontinuities both as a frontal and lateral ramp, completely inverting their movement. During the compressional stage the west-dipping listric normal faults were reactivated in positive sense. The former east-dipping normal faults have been eastward rotated or offset by thrust faults.

Pre-existing cross-structures and active fault segmentation in the northern-central Apennines (Italy)

The multideformed axial zone of the Apennines provides a great opportunity to explore the influence of pre-existing cross-structures (inherited from pre-Quaternary tectonic phases) on the segmentation of Quaternary/active seismogenic extensional faults. Detailed geological and structural data and their comparison with seismological data show that although the attitudes (strike and dip) of oblique pre-existing faults are certainly an important factor in determining a segment boundary, the size of the inherited oblique structures seems to be more crucial. Pre-existing cross-structures with lengths ranging from several kilometers to a few tens of kilometers show a twofold behavior. They can act as segment barriers during the rupture of a single fault segment or they can be reactivated as transfer zones inducing the activation of two adjacent segments that belong to the same fault system. Regional basement/crustal oblique pre-existing cross-structures, with lengths ranging from several tens of kilometers to hundreds of kilometers (commonly NNE-striking), may act as “persistent structural barriers” that halt both fault segment and fault system propagation, thus determining their terminations and maximum sizes. In the northern-central Apennines, the NNE-striking Ancona–Anzio, Valnerina, and Ortona–Roccamonfina tectonic lineaments, although having been repeatedly reactivated since the Mesozoic, represent the most important examples of these structures. Moreover, probably due to their misorientation with respect to the present extensional stress field, regional NNE-striking pre-existing structures appear to be less likely to produce strong magnitude events (no surface evidence for Quaternary faulting has been found thus far and historical and instrumental seismicity shows only M < 6 events). M ~ 7 event, on the other hand, is more likely to occur along the (N)NW–(S)SE trending normal fault systems. Lastly, we propose a model that can explain the different sizes of fault segments and fault systems on the basis of their location with respect to the “persistent structural barriers” and their spacing. In this view, our results may contribute to a more reasonable assessment of the nature and size of future surface ruptures in the northern-central Apennines, which are of critical importance to estimating seismic hazard.

Deep geometry and rheology of an orogenic wedge developing above a continental subduction zone: Seismological evidence from the northern-central Apennines (Italy)

Data from high-density seismic networks deployed between 2000 and 2007 in the north-central Apennines (Italy) yield unprecedented images of an active orogenic wedge. Earthquake foci from the northern Apennines define a Benioff zone deepening westward from the Adriatic foreland down to ~60 km depth below the chain. The seismicity shows that only the lowermost ~10 km of the Adriatic foreland crust is subducted, whereas the uppermost ~20 km is incorporated into the orogenic wedge. Farther west, an aseismic mantle with markedly negative P-wave-velocity (V p ) anomalies is interpreted as asthenosphere flowing toward an Adriatic slab in retrograde motion. Three and seismicity characteristics are imaged below the northern Apennines: an uppermost 10-km-thick fast crustal layers with different V p layer affected by extensional faulting, a slow layer with diffuse seismicity down to ~15 km depth, and a lowermost fast and aseismic layer resting directly above the asthenosphere. We interpret the latter layer as having formed by anhydrous crust undergoing granulitization, whereas trapped CO 2 (either from the underlying granulites or from the subducting Adriatic crust) is inferred to have been responsible is released along the easternmost normal fault systems breaking for both low V p and diffuse seismicity in the middle crust. Trapped CO 2 the Apennine upper crust, consistent with geochemical and seismotectonic evidence. Compressive earthquakes at 20–25 km depth along the external front suggest offscraping of the subducting foreland crust and show that asthenospheric flow represents the primary source of ongoing shortening along the belt front.

Origin, transport and discharge of CO 2 in central Italy

This paper reviews published geochemical and isotopic data (together with new data) on: (1) thermal and cold springs emerging after long circulation in a regional Mesozoic carbonate reservoir; (2) gas vents (mostly CO 2) associated with thermal and cold springs and those emerging as dry gas emissions; and (3) active and fossil travertine deposits in a large sector of central–southern Italy, from Florence to south of Naples. The origin and transport of CO 2 and its effects on water–rock interactions during transfer through the shallow crust and discharge to the atmosphere are described. Diagrams and cross-comparison of isodistribution maps of: (1) heat-flow; (2) δ 18O of thermal springs; (3) elevation of thermal springs; (4) calculated pCO 2 in thermal springs; (5) 3He/ 4He ratio in gas vents; (6) Sr concentration in thermal springs; (7) Sr concentration in travertines; (8) δ 13C in CO 2 gas emissions; and (9) δ 13C of fossil and active travertines, show systematic geographic zonation in values of δ 13C in CO 2 gas and travertines, Sr concentration in thermal springs and travertines, pCO 2 in thermal springs and the 3He/ 4He ratio in gas phases sampled at surface in central–southern Italy from the western back-arc volcanic Tyrrhenian sector towards the eastern foredeep Adriatic sector. In their lateral westward flow towards the Tyrrhenian coast, meteoric waters precipitating in the high eastern Apennine range mix with ascending magmatic, metamorphic and geothermal fluids in the highly permeable Mesozoic limestones. This fluid mixing causes transfer of poorly condensable components (among which CO 2 and H 2S) into the regional aquifer and enhances dissolution of limestone to occur faster than in typical, non-thermal karst systems. The carbon isotopic compositions of travertines precipitated along the peri-Tyrrhenian sector are correlated with the carbon isotopic compositions of parent CO 2 (metamorphic or organic), whereas the 87Sr/ 86Sr ratios of travertines inherit the isotopic signature of the dissolved Mesozoic carbonate rock. Although subduction is presently inactive in the northern–central Apennines, the distribution of fluids is typical of active volcanic arcs. Because travertine precipitation is clearly related to climate conditions and all dated travertines in Italy are younger than 500 ka, the analysis of data, in particular the parallel areal distribution of Sr concentration in present thermal springs and fossil travertines, suggests that the westward regional fluid motion has been ongoing since at least 500 ka.

Upper mantle velocity structure beneath Italy from direct and secondary P-wave teleseismic tomography

High-quality teleseismic data digitally recorded by the National Seismic Network during 1988-1995 have been analysed to tomographically reconstruct the aspherical velocity structure of the upper mantle beneath the Italian region. To improve the quality and the reliability of the tomographic images, both direct (P, PKPdf) and secondary (pP,sP,PcP,PP,PKPbc,PKPab) travel-time data were used in the inversion. Over 7000 relative residuals were computed with respect to the IASP91 Earth velocity model and inverted using a modified version of the ACH technique. Incorporation of data of secondary phases resulted in a significant improvement of the sampling of the target volume and of the spatial resolution of the heterogeneous zones. The tomographic images show that most of the lateral variations in the velocity field are confined in the first ~250 km of depth. Strong low velocity anomalies are found beneath the Po plain, Tuscany and Eastern Sicily in the depth range between 35 and 85 km. High velocity anomalies dominate the upper mantle beneath the Central-Western Alps, Northern-Central Apennines and Southern Tyrrhenian sea at lithospheric depths between 85 and 150 km. At greater depth, positive anomalies are still observed below the northernmost part of the Apenninic chain and Southern Tyrrhenian sea. Deeper anomalies present in the 3D velocity model computed by inverting only the first arrivals dataset, generally appear less pronounced in the new tomographic reconstructions. We interpret this as the result of the ray sampling improvement on the reduction of the vertical smearing effects.

Geomorphological mapping and derivative mapping of soil erosion and soil erosion hazard in the basin of the Diaterna Valica Creek (Northern Central Apennines, Italy)

Geomorphological mapping and derivative mapping of soil erosion and soil erosion hazard in the basin of the Diaterna Valica Creek (Northern Central Apennines, Italy)

Runoff and erosion control with hill farming in the sub-coastal Apennines climate

In the hilly sub-coastal Apennines climate, farming with new soil-management systems in the last 30 years has increased runoff and soil erosion. The main features of such a change are crop specialization, shaping and enlargement of the fields, tilling up and down the slope, and removal of mechanical structures, used for water management and erosion control. The effectiveness of lucerne ley and contour ditches in reducing runoff and soil erosion was evaluated in a clay, hilly area of the Northern-Central Apennines (Guiglia, Modena, Italy). Lucerne ley in the rotation was very effective in controlling upland runoff and reducing soil erosion. The runoff coefficient and soil loss, in plots with arable crops, were 0.30 and 9 Mg ha −1 yr −1, respectively, while in the lucerne ley plots these values were 0.21 and 3 Mg ha −1 yr −1, respectively. Very little was accomplished in water management and erosion control by tilling on the contour instead of up and down the slope. In fact, the runoff coefficient was, respectively, 0.14 and 0.12 and the soil loss 2.4 and 2.6 Mg ha −1 yr −1 for these two management systems. On the other hand, ditching on the contour, reduced the runoff coefficient from 0.25 to 0.16 aad the soil loss from 38.3 to 1.7 Mg ha −1 yr −1 on fields with arable summer crop. However, in very rainy years, ditching on the contour was not enough to control runoff and soil erosion in arable land. During this type of season the runoff coefficient was 0.37 and soil loss 16.5 Mg ha −1 yr −1. In the same years, a combination of ditching on the contour and lucerne ley gave much better protection, reducing the runoff coefficient to 0.19 and the soil loss to 2 Mg ha −1 yr −1.