A geological map can be considered one of the best tool to display the geometrical relationships among different geological bodies. Moreover their extent can be appreciated in three dimensions, applying geometrical techniques, when topographic and structural data are available. The aim of this work is to show how geological cartographic field data stored in a Geographic Information System (GIS) can be used for 3D modeling of complex geological bodies, using a procedure which has been established for this purpose. 3D reconstruction has been performed in gOcad. This software is based on the discrete smooth interpolator, which makes possible the construction of 3D surfaces, volumes and grids starting from simple elements with an atomic structure, as points and lines. These techniques, chiefly based on the use of cartographic data, have been applied to the reconstruction of a deep seated slope gravitational deformation developed within the sedimentary cover of the Southern Alps, Bergamo, Italy. The DSSGD occurs within a complex thrust stack, later affected by strike-slip and normal faults. These structures have been modelled basing on detailed structural, morpho-structural and geological field data (1:5,000-1:2,000). Photointerpretation techniques have been used for morphological analyses. All these data were firstly stored and integrated within a GIS, to be later generalized and imported into gOcad. The 3D model was reconstructed through several steps which will be described in detail. 3D modelling offers several advantages. First of all, a rigorous check of the consistency of the surface geology and of 2D interpretative sections was possible, taking to a general improvement of the geometrical interpretation of the Zuccone DSSGD and to 3D retrodeformation of the slided rock masses. Moreover the geometric features of the reconstructed geological bodies can be used to design preliminary monitoring plans or subsurface investigations through seismic surveys and drilling. In addition, the construction of 3D grids, where properties are added, can represent a starting point for geomechanical numerical modeling.
GIS and 3D geological reconstruction in the Southern Alps: the Zuccone gravitational deformation, Val Taleggio (BG), Italy
Zanchi A;Sterlacchini S
2004
Abstract
A geological map can be considered one of the best tool to display the geometrical relationships among different geological bodies. Moreover their extent can be appreciated in three dimensions, applying geometrical techniques, when topographic and structural data are available. The aim of this work is to show how geological cartographic field data stored in a Geographic Information System (GIS) can be used for 3D modeling of complex geological bodies, using a procedure which has been established for this purpose. 3D reconstruction has been performed in gOcad. This software is based on the discrete smooth interpolator, which makes possible the construction of 3D surfaces, volumes and grids starting from simple elements with an atomic structure, as points and lines. These techniques, chiefly based on the use of cartographic data, have been applied to the reconstruction of a deep seated slope gravitational deformation developed within the sedimentary cover of the Southern Alps, Bergamo, Italy. The DSSGD occurs within a complex thrust stack, later affected by strike-slip and normal faults. These structures have been modelled basing on detailed structural, morpho-structural and geological field data (1:5,000-1:2,000). Photointerpretation techniques have been used for morphological analyses. All these data were firstly stored and integrated within a GIS, to be later generalized and imported into gOcad. The 3D model was reconstructed through several steps which will be described in detail. 3D modelling offers several advantages. First of all, a rigorous check of the consistency of the surface geology and of 2D interpretative sections was possible, taking to a general improvement of the geometrical interpretation of the Zuccone DSSGD and to 3D retrodeformation of the slided rock masses. Moreover the geometric features of the reconstructed geological bodies can be used to design preliminary monitoring plans or subsurface investigations through seismic surveys and drilling. In addition, the construction of 3D grids, where properties are added, can represent a starting point for geomechanical numerical modeling.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
