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Abstract: In specific geological contexts, such as alluvial environments, the lithology is highly heterogeneous and laterally variable. As a result, a large number of lithological data are collected (generally random and under sampled) for stratigraphic reconstruction. The integrated management of geo-lithologic data causes major methodological problems, because data obtained from geognostic investigations have to be normalized and correlated. Data are often affected by their degree of precision, a detail depending on the investigation technique and on the geologist''s interpretation. This paper presents a methodological approach to organizing, integrating, and interpolating subsoil, mechanical (boreholes, penetration tests), and geophysical (seismic profiles, resistivity sounding) investigations for the construction of a three-dimensional geological model supported by geographical information systems and geostatistics. A practical application concerning the lower Foglia river alluvial deposits (Northern Marche, Italy) was carried out to investigate the geometry of these sedimentary bodies. This integrated approach offers many advantages for the understanding and in-depth visualization of the geometry of the deposits. Moreover, it allows for the acquisition of qualitative and quantitative information about hydrogeological settings, which is useful for water resources exploitation and protection. The achieved goals are the design of a data management workflow for geo-lithological data, the construction of a three-dimensional geological model of the lower Foglia river alluvial plain, a comparison between the geological sections obtained from the model and those made in a traditional manual fashion, and, in addition, new stratigraphic and hydrogeological considerations about the study area. [Copyright &y& Elsevier]

Abstract: Both the hardware and software available for digital geological mapping (DGM) have advanced considerably in recent years. Mobile computers have become cheaper, lighter, faster and more power efficient. Global Positioning Systems (GPS) have become cheaper, smaller and more accurate, and software specifically designed for geological mapping has become available. These advances have now reached a stage where it is effective to replace traditional paper-based mapping techniques with those employing DGM methodologies. This paper attempts to assess and evaluate two currently available DGM systems for geological outcrop mapping: one based on a Personal Digital Assistant (PDA) running ESRI “ArcPad”, and the second based on a Tablet PC running “Map IT” software. Evaluation was based on field assessment during mapping of a well-exposed coastal section of deformed Carboniferous and Permian rocks at N. Tynemouth in NE England. Prior to the field assessment, several key criteria were identified as essential attributes of an effective DGM system. These criteria were used as the basis for the assessment and evaluation process. Our findings suggest that the main concerns presented by sceptics opposed to DGM have largely been resolved. In general, DGM systems using a Tablet PC were found to be most suitable for a wide range of geological data collection tasks, including detailed outcrop mapping. In contrast, systems based on a PDA, due to small screen and limited processing power, were best suited for more basic mapping and simple data collection tasks. In addition, PDA-based systems can be particularly advantageous for mapping projects in remote regions, in situations where there is a limited power supply or where total weight of equipment is an important consideration. [Copyright &y& Elsevier]

An integration of seismological data with geological and geomorphological information aided by seismic interpretation was performed to characterise the Quaternary tectonic evolution of the Metauro River basin area (northern Marche) and adjacent off-shore sector of the external Northern Apennines. On-shore, along the Adriatic coast, the youngest age of thrusting and folding post-dates the Early-Middle Pliocene, while Pleistocene deposits appear to be, at least in part, not involved in the deformation. Recent (i.e. post-thrusting) tectonic structures have been recognised both in pre-Quaternary substratum rocks and in Upper Quaternary continental deposits (Upper Pleistocene terrace alluvium, Upper Pleistocene–Holocene slope deposits). These faults are all compatible with a WSW–ENE oriented extension. In the Metauro River basin area, preserved flights of stream terraces have been categorised according to the presence or absence of alluvial suites in relationship to each terrace level. Here, based on both the heights above the valley floor and the areal distribution of stream terraces, a generalised vertical tectonic uplift can be inferred, particularly during the Middle–Late Pleistocene. Moreover, the along-valley distribution of stream terraces provides further constraints on the age of thrusting and folding. In fact, the reconstructed terrace-levels are substantially parallel, and no evidence for any significant deformation by fold activity has been recognised. Local deformation displayed by both terrace surfaces and alluvial/slope-waste deposits suggests, instead, the intervening of some minor differential movements associated with the generalised uplift and/or to Middle–Late Pleistocene normal faulting. Their occurrence appears anyhow to be unrelated with the pattern of folds and associated thrusts. The present-day seismic activity of the study area was considered by analysing 83 seismic events that occurred from 1987 to 2000. The epicentre distribution is very scattered, and depths are generally comprised within the first 20 km of the crust, clustering between 0 and 15 km. Most of the events have magnitude <3.0, while only a few of them (12) have magnitude between 3.0 and 4.2. Focal mechanisms were obtained for eight events. The results are complex, showing fault plane solutions of “normal fault”, “thrust fault” and “unknown” types, according to commonly used stress categories. The low level of seismicity and the inhomogeneity of fault plane solutions confirm that, in the study area, this kind of data cannot provide clear constraints with respect to the problem of the occurrence or lack of activity along the thrust front. Finally, the Quaternary marine succession was studied in the northern Adriatic off-shore. Lower Pleistocene deposits appear to be slightly involved in the deformation associated with the frontal thrust of the Apennine chain. In contrast, the upper part of the Quaternary succession is clearly undeformed, showing planar and horizontal reflectors, which seal the most external thrusts of the belt. These data suggest that thrusting at the front of the Northern Apennines ended in Early Pleistocene times. Our integrated results indicate that, since Middle Pleistocene times, the external front of the northern Marche Apennines has been inactive. A generalised uplift has taken place, with subordinate tectonic activity being characterised by ENE–WSW extension and NNW–SSE compression. These main features of the stress field, although with spatial permutations of the principal stress axes, also characterise most of the external Northern Apennines during the whole Middle Pleistocene–Holocene time span. [Copyright &y& Elsevier]