GNGTS 2019 - Atti del 38° Convegno Nazionale

66 GNGTS 2019 S essione 1.1 densifying process mainly accommodated by diffusion mechanisms (i.e., grain boundary and volume diffusion) (Rahaman, 2003). Sintering is divided in three main stages (initial, intermediate and final), where the packing density (i.e., the ratio between the volume of solids and the total volume) increases till over 0.9 by rearranging and shrinking of initial spherical particles. Textures possibly associated to the final stage of sintering have been recognized in both Venere Seismogenic Fault and in theAlto di Cacchia DGSD. Irregular grain boundaries and indentation structures due to pressure-solution processes were identified in the slipping zones of Colle Cerese and Monte Ocre DGSDs and in the Campo Felice and Valle Force NF. Here, clay minerals and oxides, which limit the grain boundary mobility by pinning mechanisms (Olgaard and Evans, 1986), define the stylolites. Conclusions. In the Italian Central Apennines, some of the polished and sharp slip surfaces cutting carbonate rocks may be related to both seismic faulting or deep-seated gravitational landslides. The structural data of the Alto di Cacchia DGSD (which include open fractures dipping at high angle) suggest a shallower formation depth of this structure with respect to the Valle Force Normal Fault, which, instead, includes conjugate shear fractures dipping from medium to high angles (stereograms in Fig. 2). Under the optical microscope, the PSZs of the scarps associated to normal faults are thicker and less deformed than those associated to DGSDs. However, at the micro-metric scale, the microstructures found in the PSZs are very similar in NFs and DGSDs, suggesting the activation of grain-size dependent and diffusive-type processes. According to the dataset presented here, we conclude that the structural and microstructural features relative to the analyzed DGSDs represent important factors in their characterization when integrated with geomorphological and paleoseismological observations. References Galadini, F., 2006. Quaternary tectonics and large-scale gravitational deformations with evidence of rock-slide displacements in the Central Apennines (central Italy). Geomorphology 82, 201–228. Gori, S., Falcucci E., Dramis F., Galadini F., Galli P., Giaccio B., Messina P., Pizzi A., Sposato A., Cosentino D., 2014. Deep-seated gravitational slope deformation, large-scale rock failure, and active normal faulting along Mt. Morrone (Sulmona basin, Central Italy): Geomorphological and paleoseismological analyses. Geomorphology 208, 88–101. Moro, M., Saroli, M., Gori, S., Falcucci, E., Galadini, F., Messina, P., 2012. The interaction between active normal faulting and large scale gravitational mass movements revealed by paleoseismological techniques: a case study from central Italy. Geomorphology 151 (152), 164–174. Olgaard, D., Evans, B., 1986. Effect of Second-Phase Particles on Grain Growth in Calcite. J Am Ceram Soc 69, 272-277 . Rahaman. M., 2003. Ceramic processing and Sintering, 2 nd edition Sibson, R., 1977. Fault rocks and fault mechanisms. Journal of the Geological Society 133, 191-213. Saroli M., Lancia M., Moro M., Falcucci E. Gori S., 2017. Individuazione e rappresentazione delle Deformazioni Gravitative Profonde di Versante della Regione Abruzzo. Convenzione di Ricerca tra DICeM e INGV, Progetto MIUR-FIRB “Abruzzo”, Prot. N. 12281/04-07-2017.