Sandro Rossato | Università degli Studi di Padova (original) (raw)

Papers by Sandro Rossato

arXiv (Cornell University), Dec 3, 2018

This paper presents the abundances and the size-frequency distributions (SFD) of the ejected boul... more This paper presents the abundances and the size-frequency distributions (SFD) of the ejected boulders surrounding the Linnè crater, located on the Moon's Mare Serenitatis basin. By means of Lunar Reconnaissance Orbiter Camera high-resolution images we prepare a context geological map of the Linné crater as well as we identify ~12000 boulders ≥ 4.4 m, with a maximum measured size of 30.8 m. The cumulative number of boulders per km 2 is fitted with a power-law curve with index-4.03 +0.09/-0.10. By studying the radial ejecta abundances, we find that the largest ones are located within the first 2 km from the crater's centre, while few tens of boulders with sizes < 8 m are detectable above 5 km from the crater's rim. We find that the Linné proximal ejecta blanket is slightly asymmetrical, as indicated in the geological map too, showing a density increase in the NE-SW direction. This may be the result of an oblique impact emplacement of the original impactor, or it may be explained with a perpendicular impact in the Mare Serenitatis location, but on a surface with lunar basalts with different local mechanical properties. By exploiting our boulders size density as a function of the distance from the crater's centre, we derive a possible regolith thickness at the Linnè impact of 4.75 m, supporting similar values based on Earth-based radar and optical data in the Mare Serenitatis basin.

Planetary and Space Science, Apr 1, 2022

The Eridania paleolakes system, located along the 180° meridian at the boundary of Terra Cimmeria... more The Eridania paleolakes system, located along the 180° meridian at the boundary of Terra Cimmeria and Terra Sirenum (Fig. 1), is considered to be one of the largest lacustrine environments that were once present on Mars [1]. Morphological features suggest that it was constituted by three major connected depressions [2-4] filled by water to maximum depths of ∼2400 m and a volume of at least 562000 km [5]. Such body of water exceeded the volume of all other lakes on Mars combined [6], but due to the lack of major tributaries flowing into this basin, its existence is believed to have been related to groundwater springs, with minor contributions from overland flow [7]. Several sedimentary mineralogies have been recognized there (e.g. [8,9]) supporting the interpretation of i) a low-energy and long lasting (Late Noachian to Early Hesperian) depositional environment characterized by the presence of ponding water and ii) a warm Martian paleoclimate with a stable highland water table more t...

Deep-seated gravitational slope deformations (DSGSDs) are well-known to affect the landscape and ... more Deep-seated gravitational slope deformations (DSGSDs) are well-known to affect the landscape and the morphology of Alpine valleys. In contrast, little is known on their influence on Quaternary deposits. This paper, focused on the Western Italian Alps, aims to fill this gap. Eight case studies, identified after a long term field experience, are presented, representative of different geological settings. To fully define their distinctive features, such sites have been characterized using various methods: geological surveys, geophysics and geomatic techniques. DSGSD proved to influence the sediment deposition primarily with the continuous supply of centimetric/decimetric angular clasts. This have different consequences on sediments, depending on their features, in some cases deeply modifying their typical facies (i.e., glacial, colluvial and lacustrine sediments), whilst in other cases their influence is less evident (i.e., debris, avalanche and torrential deposits). This paper can be a useful tool when dealing with DSGSD-related deposits, helping avoid misinterpretations.

Frontiers in Earth Science

We investigated the Mt. Peron niche area of the Masiere di Vedana rock avalanche (BL), one of the... more We investigated the Mt. Peron niche area of the Masiere di Vedana rock avalanche (BL), one of the major mass movements that affected the Eastern Southern Alps in historical times. So far, a geomechanical characterization and a stability analysis of the niche area, where potential rockfall sources are present, are lacking. The Mt. Peron niche area is a rocky cliff almost inaccessible to field-based measurements. In order to overcome this issue, we performed a geo-structural characterization of a sector of the cliff by means of a UAV-based photogrammetric survey. From the virtual outcrop, we extracted the orientation of 159 fractures that were divided into sets based on a K-means clustering algorithm and field-checked with some measurements collected along a rappelling descent route down to the cliff. Finally, with the aim of evaluating the stability of the volume under investigation, we performed a stability analysis of three rock pillars included in our survey by means of a distinct...

&amp;lt;p&amp;gt;Landslides are very efficient in shaping mountain landscapes, mo... more &amp;lt;p&amp;gt;Landslides are very efficient in shaping mountain landscapes, modifying the drainage pattern of the valleys, forcing people to adapt, react or counter them. In particular, valleys in the southern side of the Alps are narrow, with very steep slopes, and often have been inhabited since prehistoric times.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;The Tovel Valley is located in the Adamello Brenta Nature Park in the northern Brenta Dolomites, near a lake (Tovel lake) that is famous for its, at times, red colour. This valley can be found in the central-eastern Southern Alps, along the western margin of the Adriatic indenter. Here, tectonic forces started to act in the Late Cretaceous, during the initial phases of the Alpine orogenic history, and are still active today. Moreover, the Trentino Region is one of the most seismically active sectors of Northern Italy, with significant historical and instrumental earthquakes typically clustered in very good agreement with tectonic structures. N-S oriented vertical strike-slip faults determined the shape of the Tovel Valley, favouring the occurrence of prominent source detachment scarps on the eastern valley side. The Tovel lake, whose origin is still debated if due to glacial processes or landslide events, records a sudden rise in its level, testified by the drowning of a submerged forest dated by dendrochronology at 1597 AD. This event is interpreted as due to a minor rockfall, which blocked the outflow channel on the north-eastern lakeside. This event had direct consequences on people living in the area, that were forced to find timber elsewhere, but also older, and larger, rock avalanches likely affected people living in the valley.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Whilst Tovel lake has been studied for a long time, the blocky deposits of the Tovel Valley gathered much less attention. By means of field mapping, remote sensing and cosmogenic &amp;lt;sup&amp;gt;36&amp;lt;/sup&amp;gt;Cl exposure dating, we reconstruct the age and the evolution of the blocky deposits that occupy large areas of the valley bottom, with implications directly connected to the formation and evolution of the Tovel lake. Landslide deposits cover an area of ~5 km&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; and are composed of seven bodies distributed at different elevations, ranging from ~1900 to ~900 m a.s.l. Their total volume is estimated at 200&amp;amp;#8211;280 Mm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt; of debris made of Dolomia Principale and Calcare di Zu Formations. Detachment areas are mainly located along the eastern valley side, with six out of seven events that can be classified as rock avalanches.&amp;lt;/p&amp;gt;

Tectonics, 2021

Moulin and Benedetti (2018), https://doi.org/10.1029/2018TC004958 present a new interpretation of... more Moulin and Benedetti (2018), https://doi.org/10.1029/2018TC004958 present a new interpretation of the Neogene‐Quaternary tectonic evolution of the Eastern Southern Alps (ESA) in Veneto‐Friuli. After the reinterpretation of literature field data by means of remote sensing analysis (Digital Elevation Model interpretation), they calculated deformation rates of the tectonic structures through age interpretation of geomorphological surfaces of the Veneto‐Friuli piedmont plain. The authors linked the result of surface analysis to the thrust and fold architecture of the ESA basing on the Castellarin et al. (2006), https://doi.org/10.1016/j.tecto.2005.10.013 interpretation of TRANSALP project and the Friuli geological map at the scale 1:150,000 (Carulli, 2006). Discussing their new architecture of the ESA, the authors finally yielded rates of Europe‐Adria plates convergence and suggested fragmentation of Adria over the last 1–2 Ma. The present comment is aimed at discussing several critical points concerning: the use of the geomorphological and chronological data; the misinterpretation of the Digital Terrain Model; the reconstruction of the balanced geological cross section. Moreover, the application of a structural model defined in a certain area to another without considering peculiar structural complexities available in the literature results is geologically and methodologically questionable.

Gouges and cataclasites within exhumed fault zones are valuable indicators of past seismic events... more Gouges and cataclasites within exhumed fault zones are valuable indicators of past seismic events. Gouge layers, 40- to 100-cm-thick and decameters long, have been found within uplifted Cretaceous limestones in the Euganean Hills (SW of Padova, NE Italy), Cenozoic subvolcanic chambers intruded within a Meso-Cenozoic sequence. The main tectonic lineament in the area is the Schio-Vicenza Fault that bounds the Euganean Hills to the East. Micropaleontological analyses reveal that the gouges derive from the fragmentation and pulverization of the adjacent pristine carbonatic rocks. Stress tests on specimens from bedrock associated with gouges yielded a minimum dissipated strain energy of 0.3–0.5 MJ/m3 to shatter them. Henceforth, additional strain energy was necessary to pulverize these rocks within the gouge zones. Global navigation satellite system observations show that the present deformation pattern in this region of Italy is a few tens of nanostrain (10–30 1/y), not enough to genera...

EGUGA, Apr 1, 2015

One of the most interesting morphological feature on the surface of Mars are paleolakes: time cap... more One of the most interesting morphological feature on the surface of Mars are paleolakes: time capsules and low-energy depositional settings that preserve hints on the ancient environment and, possibly, traces of life. On Earth, lakes host a huge diversity of habitats where life is flourishing; hence, on Mars, they may have once supported life too. In order to understand the paleohydrology of these basins, the estimation of the water discharge flowing into their tributary and/or outlets can give important clues on the water cycle on the planet. On Mars, the most common modeling used to reconstruct the hydraulic properties are based on the adaptation of terrestrial empirical relationship, less focusing on more sophisticated hydraulic models. The main objective of this study is to separately analyze the hydraulic characteristics of the tributary and the outlet of a paleolake located in the Menmonia quadrangle by using an hydraulic model based on the energy and momentum equations of the body of water enclosed in the channels. The lengths of the analyzed river reaches are ∼ 10 km and ∼ 19 km, the outlet and the tributary respectively. A Monte Carlo procedure coupled to geomorphological evidences of the paleowater surface (e.g. terraces levels) were used to constrain the hydraulic parameters of the system. The Mars Express High-resolution stereo camera digital elevation model, H31850000DA4 with a spatial resolution on 75 m, is hence used to characterize the geometry of the study area. In this contribution we provide estimates on the magnitude of the bankfull discharge and roughness coefficient of the tributary and the outlet of the paleolake; moreover, on the basis of these results, the probable water depth of the lake is inferred. Finally, a discussion on the possibility that the system inlet-lake-outlet was acting simultaneously is also presented. Consequently, a sensitivity analysis is performed to examine the accuracy of the results to the main sources of uncertainty concerning the methodology, as well as, the uncertainty in the geomorphological evidences used to constrain the hydraulic modelling. Given the comparable discharge estimates of the tributary and the outlet, as well as the coherent elevation and width of their mouths into the lake, the results suggest that both channels were most probably acting simultaneously during their last evolutionary phase, with a discharge equal to ∼ 6000 m 3 s −1 and a water surface elevation in the lake equal to ∼-1400 m. This contribution supports the hypothesis of an ancient and articulated hydrologic system acting in the study area.

&lt;p&gt;The Gavon basin hosts one of the major landslide deposits of the Eastern... more &lt;p&gt;The Gavon basin hosts one of the major landslide deposits of the Eastern Italian Dolomites (Falcade, Belluno). This deposit is due to different phases of erosion carried out by the Gavon, which is a sinistral tributary of the Cordevole River, and it consists of a thick erodible sequence of Upper Permian Bellerophon Formation and Lower Triassic Werfen Formation (divided into Tesero, Mazzin, Andraz, Siusi, Gastropod Oolite, Campil, Val Badia, Cencenighe, San Lucano Members) that have been tectonically duplicated by thrust activity and uplifted by two superposed folding and diapiric deformations, rising the sequence to an elevation of 2499 meters a.s.l. at the Forca Rossa pass.&lt;/p&gt;&lt;p&gt;The Gavon basin is 5.98 km long and is characterized by a mean slope greater than 18%. The Lower Triassic sequence was eroded producing a 7.86 km&lt;sup&gt;2&lt;/sup&gt; basin in pre-glacial time. The basin was filled up by early landslide deposits before the last glaciation, which onset date back to about 30 thousand years before present, and during historic time.&lt;/p&gt;&lt;p&gt;The catchment is now subjected to high erosion due to the frequent rainfall/snowfall events. The solid transport has always been high (up to 34400 m&lt;sup&gt;3&lt;/sup&gt;/y) and, for this reason, some dams were built 80 years ago. Three more check dams were built in 2005 to further decrease the erosion.&lt;/p&gt;&lt;p&gt;A reconstruction of the events in the postglacial time is carried out based on (a) the volume of the deposits and (b) the missing volume in the detachment area. A volume of 173 to 216 million cubic meters has been eroded by a series of events (or a unique large event) that ended approximately 4000 years ago (Fenti, 2018).&lt;/p&gt;&lt;p&gt;To complete this analysis, we numerically modelled the detachment and runout of a block of rock located in the top portion of the basin, where some tension cracks are now evident, and assuming that an intense rain event could mobilize it. The analysis has been processed using LiDAR data with QGis software, while the simulations are performed with GeoFlow-SPH.&lt;/p&gt;

This work presents an example of lacustrine and fluvial terraces correlation, a useful approach f... more This work presents an example of lacustrine and fluvial terraces correlation, a useful approach for the understanding and reconstruct past changes in landscape evolution not only on Earth but also on Mars

1 Laboratoire de Géologie de Lyon Terre, Planètes, Environnement (CNRS-ENSLyon-Université lyon1),... more 1 Laboratoire de Géologie de Lyon Terre, Planètes, Environnement (CNRS-ENSLyon-Université lyon1), ERC eMars Team, 2 rue Raphaël Dubois 69622 Villeurbanne Cedex, France, 2 Institut d'Astrophysique Spatial, Université Paris 11-Orsay, France, 3 Department of Earth and Planetary Sciences, Birkbeck, University of London, London, UK, 4 Center of Studies and Activities for Space CISAS “G. Colombo”, University of Padova, Padova, Italy, 5 School of Civil Engineering, Department DICAM, University of Bologna, Bologna, Italy, 6 Geosciences Department, University of Padova, Padova, Italy, 7 LESIA , Meudon.France

Oceanographic surveys are an important tool in the investigation of quaternary deposits and morph... more Oceanographic surveys are an important tool in the investigation of quaternary deposits and morphologies located on sea floors. Their importance and potentialities in geomorphologic applications are here discussed in details, taking as example the SomRISA09 survey (North Adriatic Sea, 28/04/2009 – 07/05/2009). During this survey, University of Padua and CNR-ISMAR worked together to realize the DEM of the north-Adriatic sea and to connect it to DTM of the Venetian plain, created by the Department of Geography (University of Padua). Thanks to this DEM it was possible to appreciate the good preservations status of the LGM deposits. Together with this project, the CNR-ISMAR runned some other analyses; the involved instrumentation is here described, pointing out their potentialities and limits.

Sampling was based on the size of the boulders and stable position, single stage of exposure, con... more Sampling was based on the size of the boulders and stable position, single stage of exposure, continuous exposition in the same position (not shifting), no coverage; minimal surface of weathering or erosion (karren encased for at maximum 0.5 cm). The samples VB3a, VB3c, VB14 were taken on the Mt. Peron slope at different altitude, VB2 on the right bank of the Cordevole, in the Vedana area and VB12, VB13a and VB13b come from the southernmost part of the deposits, in the Roe Alte sector. The main characteristics of the dated samples are here reported. VB2. The sample comes from a grey metric boulder on the right bank of Cordevole river. The rock belongs to Calcari Grigi Group and had a network of black calcite veins. Thin section shows that the rock is a peloidal packstone, with micritic matrix. It is possible to recognize fragments of echinoderm, bivalves, spicules of sponges, algae, foraminifers and peloids. VB3a. The sample comes from a metric boulder of Upper Rosso Ammonitico Fm. on the left side of Cordevole River, at the foothill of Mt. Peron, 300 m over the Peron village. The sample is a pinkish packstone with nodular structure and fragments of Saccocoma. VB3c. The sample comes from a decametric boulder of Fonzaso Fm. on the left side of Cordevole River, at the foothill of Mt. Peron, 300 m over the Peron village. The boulder is next to the VB3a sample but is way bigger. On this section the sample appears to be a bioclastic peloidal packstone with fragment of echinoderm, spicules of sponges, bivalve and calcareous algae. VB12. Sample comes from a grey Vajont limestone metric boulder with evident crinoids and algae situated in the further part of Roe Alte deposits. Thin section shows a packstone with fragment of echinoderm, bryozoan and algae, subordinately bivalves, peloid, and foraminifers. Note that oolites still show a very well preserved radial structure.

Quaternary International, 2018

The outwash rivers of the Venetian-Friulian plain promoted a high-rate aggradation during the Las... more The outwash rivers of the Venetian-Friulian plain promoted a high-rate aggradation during the Last Glacial Maximum (LGM), with large sedimentary bodies fed by major glaciers along the southeastern side of the Alps. Glaciers were temperate-type, hold up by high precipitation rates and characterized by large amount of water trapped in subglacial lakes or funneled in speedy streams. The stratigraphic analysis of these sedimentary bodies showed sharp changes from coarse gravels to well-sorted sandy gravels few kilometers downstream. Large boulders, 1 to 2 m in size, are present in many sites, especially in the Tagliamento outwash plain, from the end-moraine system to about 13 km far to the south. Most of the boulders are located on the eastern area of the sandur and lie stratigraphically above a paleosol, radiocarbon dated to 31,114±643 cal a BP, thus belonging to the LGM sandur of the Tagliamento glacier. In some locations these boulders are associated to large bars, showing a rough cross-bedding. Similar sedimentary structures are observed 2 km downstream of the LGM frontal moraines in the Astico outwash system, a 25-km-long transfluence tongue of the Adige-Brenta glacial complex. In this case the occurrence gravel dunes containing many boulders marks the evidence of a high-energy deposition. The occurrence of cross-bedded bars, embedding large boulders up to 2 m of diameter, in the piedmont plain of the southeastern Alps is peculiar. Breaks of natural dams, such as the frontal moraines or the glacier itself, may have triggered glacial lake outburst floods (GLOFs) that determined the formation of such gravel bars with meter-size clasts.

arXiv (Cornell University), Dec 3, 2018

Planetary and Space Science, Apr 1, 2022

Frontiers in Earth Science

Tectonics, 2021

EGUGA, Apr 1, 2015

Quaternary International, 2018