GNGTS 2016 - Atti del 35° Convegno Nazionale

GNGTS 2016 S essione 1.1 135 Fig. 3 – a) Scan of a thin section from a pocket of colluvium, involved in tectonic deformation, at the Pecetto di Valenza site; b) photomicrograph of the slide of Fig. 3a, illustrating the orientation of the constituents of the micromass, parallel to the main tectonic strain axis (plain-polarized light); c-d) scan of two thin sections sampled from the fault gouge: c) shows the presence of illuvial clay widespread in the weathered marl; d) the white arrow indicates joints ascribable to a first deformation phase, crosscut by the gouge associated to a later faulting event (modified after Frigerio et al. , in press). reconstruction of the local paleoseismological evolution, in fact, may take great advantages from the description of pedofeatures related to seismic stress, identified in soil thin sections, if considered together with the well-established stratigraphic approach. References Amit, R., Harrison, J.B.J., Enzel, Y., Porat, N., 1996: Soils as a tool for estimating ages of Quaternary fault scarps in a hyperarid environment—the southern Arava valley, the Dead Sea Rift, Israel. Catena, 28(1), 21-45 pp. Buol, S.W., Hole, F.D., Mccracken, R.J., 1973: Soil Genesis and Classification . The Iowa State University Press, Ames, pp. 360. Frigerio C., Bonadeo L., Zerboni A., Livio F., Ferrario M.F., Fioraso G., Irace A., Brunamonte F., Michetti A.M., in press: First Evidence for Late Pleistocene to Holocene earthquake surface faulting in the Eastern Monferrato Arc (Northern Italy): geology, pedostratigraphy and structural study of the Pecetto di Valenza site. Quaternary International. Khatwa, A., Tulaczyk, S., 2001: Microstructural interpretations of modern and Pleistocene subglacially deformed sediments: the relative role of parent material and subglacial processes. J. Quaternary Sci., 16: 507–517. doi:10.1002/jqs.609 Larson, G.J., Menzies, J., Lawson, D.E., Evenson, E.B., Hopkins, N.R., 2016: Macro- and micro-sedimentology of a modern melt-out till – Matanuska Glacier, Alaska, USA. Boreas, Vol. 45, pp. 235-251. 10.1111/bor.12149. ISSN 0300-9483. Livio, F., Berlusconi,A., Zerboni,A., Trombino, L., Sileo, G., Michetti,A.M., Rodnight, H., Spötl, C., 2014: Progressive offset and surface deformation along a seismogenic blind thrust in the Po Plain foredeep (Southern Alps, Northern Italy). Journal of Geophysical Research: Solid Earth 119, pp. 7701–7721. DOI: 10.1002/2014JB011112. McCalpin, J.P., 2009: Paleoseismology (2nd ed.) . San Diego, Academic Press, 647 pp. Menzies, J., Reitner, J.M., 2016: Microsedimentology ice stream tills from the Eastern Alps, Austria – a new perspective on till microstructures. Boreas , Vol. 45, pp. 804–827. 10.1111/bor.12189. ISSN 0300-9483. Nelson, A.R., 1992: Lithofacies analysis of colluvial sediments--an aid in interpreting the recent history of Quaternary normal faults in the Basin and Range Province, western United States . Journal of sedimentary research, 62(4), pp. 607-621. Previtali, E., 1992: Seismipedoturbations in volcanic soils in North-Eastern Ecuador . Catena, 19, pp. 441–450. Zerboni, A., Trombino, L., Frigerio, C., Livio, F., Berlusconi, A., Michetti, A.M., Rodnight, H., Spötl, C., 2015: The loess-paleosol sequence at Monte Netto: a record of climate change in the Upper Pleistocene of the central Po Plain, northern Italy. Journal of Soils and Sediments 15, pp. 1329–1350. DOI: 10.1007/s11368-014-0932-2.