No abstract

Carbonaceous materials (CMs) have been widely used to assess temperatures in sedimentary and metamorphic carbonate rocks. The use of Raman spectroscopy of carbonaceous material (RSCM) is largely devoted to the study of deformed rocks hosted in thrust-tectonic settings. Raman spectroscopy of carbonaceous material successfully allows the study of carbonate rocks at a temperature as high as 650 °C. In this study, a set of carbonate-mylonite rocks (Italian Alps) were investigated using micro-Raman spectroscopy, in order to infer the deformation conditions associated with the Alpine thrusts, expected to occur at T < 350 °C. Micro-Raman spectra were collected using two sources: green (532 nm) and red (632.8 nm) lasers. Several deconvolution procedures and parameters were tested to optimize the collected spectrum morphologies for the laser sources, also in accordance with the low temperature expected. The obtained temperatures highlight two clusters: one at 340–350 °C for the samples collected in the axial part of the Alpine chain, and the other at 200–240 °C for those collected in the external thrust-and-fold belt. These results agree with the independent geological and petrological constraints. Consistent results were obtained using 532 and 632.8 nm laser sources when the appropriate deconvolution approach was used.

&lt;p&gt;Large landslides have affected the geomorphological evolution of most Alpine territories. Some catastrophic events also had a huge impact on the economic and cultural development of human societies. In the Bregaglia Valley and in nearby territories, evidences of settlements date back to the Roman age. In these areas, human activities always coexisted with the natural evolution of the valley, which has been characterized by recurrent natural events such as floods and landslides. Among these, the 1618 Piuro landslide was the one with the strongest impact, remaining impressed on the collective imagination and artistic representations. It erased an entire village and its 1000-2000 inhabitants few km East of Chiavenna, and it is still remembered as one of the worst tragedies in the history of the region. Understanding the evolutionary dynamics of such a geomorphologically active landscape, taking notes from the ancient or recent past, plays a central role in risk assessment and mitigation. In Piuro, such dynamics were investigated through a multidisciplinary approach, starting from the historical and archaeological analyses of the event and involving: (i) the geological/geomorphological characterization of the Last Glacial Maximum, to present palimpsest landscape of the valley through the realization of thematic maps, (ii) the stratigraphic interpretation of new boreholes crossing the landslide deposits and the deeper intra-mountain sedimentary valley fill, (iii) the realization of topographic, petrographic, geophysical (HVSR and MASW) and geo-mechanical surveys. In addition, the implementation of numerical models is on the way, to check different hypotheses on the predisposing factors, triggers, timing and evolution of the 1618 Piuro landslide. To increase the awareness of natural hazards in mountain settings and to promote a risk and resilience culture, all these acquired knowledge will be disseminated and shared with citizen, authorities and scientists in the frame of the Interreg project A.M.AL.PI.18. The fulfilment of a transboundary (Italian-Swiss) geo-cultural path will link other sites of historical and geological relevance through the territories of Bregaglia, Valchiavenna, Moesa and Ticino. Showing and telling the history of catastrophic landslides and their impacts on the involved communities, it will contribute to enhance the perception of beauty and the awareness of geo-hazard. The dissemination of knowledge and awareness is one main goal towards risk mitigation.&lt;/p&gt;&lt;p&gt;The present work was co-funded through the EU, Regional Development European Fund, by Italian State, Helvetic Confederation and Cantons under the Interreg V-A IT-CH 2014-2020 Cooperation Program - A.M.AL.PI.2018 &amp;#8220;Alpi in Movimento, Movimento nelle Alpi. Piuro 1618-2018&quot;, ID 594274 &amp;#8211; Axis 2 &amp;#8220;Cultural and natural enhancement&amp;#8221;.&lt;/p&gt;

&lt;p&gt;Natural disasters, such as postglacial landslides in Alpine valleys, recurrently reshape the natural and human landscape, impacting on settlements, land-use and architecture. Historical catastrophes were sometimes narrated and painted, so that in these cases chronicles and artistic representations can be integrated to geological, geomorphological, geophysical and archaeological data to describe the co-evolution of the natural and cultural landscape. This is the case of the Piuro landslide that in 1618 almost completely buried this renown and rich trading town in the Bregaglia Valley (Italy), on the way to the relevant alpine Maloja pass. Since it totally modified the valley floor, the catastrophe represents a turning point that permits to i) attempt the 3D reconstruction of the natural and archaeological landscape before and immediately after the disaster, ii) unravel the post-1618 increments of evolution of the natural landscape and settlements, iii) retrieve the memory of the area that underwent the disaster. To accomplish these aims we integrated: a new detailed DTM; a reconstruction of the relative chronology of burial, erosion and stabilization of the landforms after natural and anthropic processes pre- and post-dating the 1618 landslide; some subsurface stratigraphic logs and images based on new boreholes and geophysical surveys; age determinations based on radiocarbon and archeological/historical data; chronicles and paintings depicting the Piuro area before and after the disaster. The images we could draw show how human settlements were continuously controlled by the occurrence of landslides and other catastrophic processes like debris flows, before and after the 1618 landscape turning point. In the valley center we could detect a pre-1618 landslide body, whose mega-boulder reliefs were settled at least since the 4&lt;sup&gt;th&lt;/sup&gt; &amp;#8211; 5&lt;sup&gt;th&lt;/sup&gt; century AD, at present buried below the Middle-ages and Renaissance Piuro villages. These landslide bodies provided also favorable settings for food preservation, whose memory and usage survived and reached the present-day under the vernacular denomination of &amp;#8220;crotti&amp;#8221;. At the millennial time scale no stable geomorphological surfaces do exist on the valley floor and lower slopes, since we could map the chronology of building of the debris flow-fan lobes, demonstrating how they evolved before and after the 1618 landslide, burying and/or being buried by the two major landslide bodies and interfingering with the trunk river alluvial sediments. Radiocarbon age determinations, archeological findings and the known ages of historical buildings permitted to recognize the geomorphological surfaces that remained stable on a shorter, secular, time scale, where the settlements could resume still competing with catastrophic processes that led to repetitive burial of several buildings during the last three centuries. Based on these results we could draw the 3D models of the Piuro area predating and immediately postdating the 1618 catastrophe. Historical paintings and chronicles largely confirm the relative chronology of landscape changes that we propose.&lt;/p&gt; &lt;p&gt;The present work was co-funded through the EU, Regional Development European Fund, by Italian State, Helvetic Confederation and Cantons under the Interreg V-A IT-CH 2014-2020 Cooperation Program - A.M.AL.PI.2018 &amp;#8220;Alpi in Movimento, Movimento nelle Alpi. Piuro 1618-2018&quot;, ID 594274 &amp;#8211; Axis 2 &amp;#8220;Cultural and natural enhancement&amp;#8221;.&lt;/p&gt;