Surface Geomorphological Features of Deep-Seated Gravitational Slope Deformations : A Look to the Role of Lithostructure (N Apennines, Italy)

The attention to deep-seated gravitational slope deformations (DSGSDs) has steadily increased in the last few decades, because such features are ubiquitous in mountain areas. Their geomorphological surface expression, especially when related to the effects of lithostructural control in sedimentary stratified bedrocks, is well characterized in theory, but sometimes not as well documented in field cases. In this contribution the investigation of several DSGSDs in the area of the Northern Apennines of Italy is reported. A survey of the area was conducted using fast and lowcost satellite imaging techniques, in order to describe the surface features of selected DSGSDs and verify how their occurrence is linked to the effect of lithostructural constrains such as bedding and folding. Surface features developed in parallel to the strike of the slope are mostly related to the main gravitative strain acting on the deformation. Features along slope dip are instead formed by the release of tension caused by compressive forces at the landslide foot or by the presence of preexisting weak lines. One example of a DSGSD, formed on the hinge of a vertical fold, shows a corrugated appearance due to the release of vertical fractures that mask most other features usually associated with DSGSDs. This potentially impairs the detection of these landforms during field and remote surveys

The Eneolithic/Bronze Age Transition at Tegole di Bovino (Apulia): Geoarchaeological Evidence of Climate Change and Land-Use Shift

Human communities at the transition between the Eneolithic period and the Bronze Age had to rapidly adapt to cultural and climatic changes, which influenced the whole Mediterranean. The exact dynamics involved in this crucial passage are still a matter of discussion. As newer studies have highlighted the key role of climatic fluctuations during this period, their relationship with the human occupation of the landscape are yet to be fully explored. We investigated the infilling of negative structures at the archaeological site of Tegole di Bovino (Apulia, Southern Italy) looking at evidence of the interaction between climate changes and human strategies. The archaeological sedimentary deposits, investigated though geoarchaeological and micromorphological techniques, show the presence of natural and anthropogenic infillings inside most structures. Both human intervention and/or natural events occurred in the last phases of occupation of the site and its subsequent abandonment. The transition to unfavorable climatic conditions in the same period was most likely involved in the abandonment of the site. The possible further impact of human communities on the landscape in that period, testified by multiple other archives, might have in turn had a role in the eventual change in land use

Matilda’s castles, northern Apennines: geological and geomorphological constrains

The positioning and construction of castles in ancient times responded not only to strategic opportunity, but also to the issue of geomorphological risk. We investigated castles and strongholds built in the era of the Great Countess Matilda of Canossa in part of the northern Apennines (Italy), in order to study the relationship between their positioning and the distribution of geomorphological and geological hazards. We observe how the location of castles follows clear patterns of avoidance of potential hazards: castles are kept far from the main fault systems and stream networks, and are mainly at a safe distance from landslide- and badlands-susceptible terrains. The knowledge of Medieval communities on landscape hazards was sufficiently advanced to minimise risks, while maintaining the strategic value of fortifications

Building on an oasis in Garamantian times: geoarchaeological investigation on mud architectural elements from the excavation of Fewet (Central Sahara, SW Libya)

The paper describes the micromorphological and mineralogical properties of earthen architectural elements from the excavation of the Garamantian compound of Fewet (Central Sahara, SW Libya), settled between the 2nd century BC and the 1st century AD, and compares this evidence with a set of samples from historical to modern context of Saharan and Sub-Saharan Africa. At Fewet, the production of mud bricks, plasters, and mortars employed in the building of the compound required raw materials available near the settlement. The earthen elements lack almost completely clay and organic temper, and their main components are quartz grains (sandy to silty) and a calcareous and slightly organic mud, available beside former springs. Only plaster and mortars show the addition (in limited quantity) of finely subdivided vegetal remains to the mixture. The technology for earthen elements used in Garamantian times resembles those today applied at many localities in Sub-Saharan Africa. Finally, our analyses showed that in the last millennia archaeological sediments underwent limited postdepositional weathering, mostly related to solute redistribution after occasional rainfalls. Today, the same process affects traditional mud brick buildings

Variable fault tip propagation rates affected by near-surface lithology and implications for fault displacement hazard assessment

The fabric of reverse fault zones close to the surface is usually partitioned in between a narrow discrete rupture zone and a more distributed one, where folding is predominant. This makes quite challenging the adoption of proper setbacks in surface rupture hazard studies for critical facilities or microzoning. Some of the parameters controlling fault zone fabric are related to mechanics of near-surface geology (lithology, overburden thickness, cohesion and water content) whose interaction is complex and only partially understood. Nevertheless, these can be seldom measured or derived. Kinematic models, conversely, express such an interaction of complex variables as simple synthetic parameters, such as the amount of upward propagation of the fault tip for unit of slip, usually referred to as the P/S ratio (Propagation on Slip). Here, we discuss results on the trishear kinematic inverse modeling of a contractional fault propagation fold at Monte Netto Hill (Capriano del Colle, N. Italy), observing a two-stage fault and fold growth evolution, marked by a significant shift in the P/S parameter. At this site, exceptional sequence of exposures due to ca. 10 years of quarry excavations allowed to obtain a series of cross-sections across the fault zone. We use this detailed, high-resolution, example as a natural \u201canalogue\u201d for more general, large-scale surface ruptures involving a thick alluvial cover, a very common setting for the siting of critical facilities. During the early stage of displacement, the fault cut through clast-supported fluvial gravels with a high propagation rate (P/S\u202f=\u202f7) and a discrete rupture width. Then, during the latest movements of the thrust, fault tip propagation slowed down to P/S\u202f 48\u202f2.9, as the fault started cutting through several stacked bodies of clays and silty clays, pedogenized aeolian silts and overbank deposits, causing a pronounced folding of the layers over a wider deformation zone. These results strongly suggest that lithological changes in the underlying shallow stratigraphy, common in an alluvial plain depositional setting, would significantly affect the potential for surface faulting across the same tectonic structure, with relevant implications in the fault displacement hazard assessment

Report on the INQUA-AEOMED field-trip workshop ‘Reconsidering Loess in Northern Italy’ (Po Plain, 1-3 July 2013)

This report presents the results of the field-trip workshop entitled \u2018Reconsidering Loess in Northern Italy\u2019 (Po Plain, 1-3 July 2013), organized in the framework of the AEOMED Project of the INQUA TERPRO Commission. The workshop focuses on presenting and discussing the sources and formation processes of the loess in the Po Plain area. The sedimentological, palaeopedological, palaeoclimatic and palaeoseismic aspects of five main loess sequences in the Po Plain (Val Sorda, Gajum, Monte Netto, Ghiardo, Boschi di Carrega) were presented and discussed in the field. The discussions carried out during three field days aim to map knowledge gaps and to define the next scientific goals in the field of loess research in the Po Plain in particular and in Italy in general