Particle size analysis is widely used in sedimentology to determine the characteristics of different depositional environments and infer flow transport and depositional processes. However for volcaniclastic flows, this methodology has been applied mainly for a descriptive purpose or for typical generic consideration of down flow variation of statistical parameters. For this study we choose the case of Nevado de Toluca volcano (Mexico) due to the previous knowledge of its geological evolution, stratigraphic succession and spatial distribution of volcaniclastic units. Grain size analyses (by coupling photo-sieving, particle size and photosedimentographic analyses) and frequency distributions curves have been carried out to characterize block-and-ash flow and debris avalanche deposits. The multivariate statistic analysis (discrimination function) shows that sedimentological parameters are good discriminators between samples belonging to block and ash flow and debris avalance deposit. In addition, the application of the same methodology within each single deposit (DAD and BAF) allows to identify the presence of subpopulations and reveals differences among proximal, medial and distal facies. The resulting subpopulations have been plotted in a GIS environment to evidence these sedimentological variation respect to the deposit thickness and flow interaction with topography. By overlapping the flow thickness map with the subpopulation statistic analyses it is possible to define the relationships between facies and its position into the flow and to provide a model of transport and deposition mechanism of debris avalanche deposit and block and ash flow at Nevado de Toluca volcano.
|Titolo:||Transport and deposition processes of volcaniclastic deposits inferred by multivariate statistic analyses and GIS applications : The case of Nevado de Toluca volcano (Mexico)|
|Data di pubblicazione:||2007|
|Parole Chiave:||Nevado de Toluca ; grain size analyses ; geostatistics ; multivariate analysis ; volcaniclastic flow characterization ; GIS applications|
|Citazione:||Transport and deposition processes of volcaniclastic deposits inferred by multivariate statistic analyses and GIS applications : The case of Nevado de Toluca volcano (Mexico) / F. Bellotti, L. Capra, G. Groppelli. ((Intervento presentato al convegno International Union of Geophisics and Geodesia tenutosi a Perugia nel 2007.|
|Appare nelle tipologie:||14 - Intervento a convegno non pubblicato|