--> Abstract: Application of GIS Techniques to Large-Scale Outcrop Studies in the Tertiary Alpine Foreland Basin of Southeast France, by Rufus L. Brunt, William. D. McCaffrey, Robert W. H. Butler, Jamie S. Vinnels, and Myron Thomas; #90039 (2005)

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Application of GIS Techniques to Large-Scale Outcrop Studies in the Tertiary Alpine Foreland Basin of Southeast France

Rufus L. Brunt, William. D. McCaffrey, Robert W. H. Butler, Jamie S. Vinnels, and Myron Thomas
Leeds University, Leeds, United Kingdom

A key Geographical Information Systems (GIS) methodology is the production of digital elevation models (DEMs) and their overlay by photographs, maps and other data. An important geological use of DEMs has been the selection of ideal, “virtual” viewing positions in order to resolve the geometric form of features not optimally exposed in outcrop. Although this qualitative methodology is worthwhile, new geological insights are perhaps most likely to follow from quantitative investigations of DEMs at basinal scales.

The deep marine clastic fill of the Tertiary Alpine foreland basin of SE France displays considerable internal architectural variation, and was subject to both syn- and post-sedimentary compressional deformation. DEMs of this area were built from 1:17,000 aerial photo stereo pairs using the Leica Photogrammetry Suite of programs (covering an area of 50 km2, later extended to >250 km2): vertical and horizontal error is < 4m for over 95% of DEM area. The models were draped with orthorectified air photos, allowing recognition of geological features (e.g., submarine channels, channel bounding surfaces, folds and thrust faults). In the GIS environment, traces of intersection of such features with the terrain surface were mapped over length scales exceeding 10km, and later extracted as surfaces for quantitative evaluation. These data allow process models describing switches between incised channel and sheet sandstone deposition to be tested. Additionally, the effect of variations in stratigraphic architecture on deformation style (buckle fold style and wavelength) can be directly evaluated. The insights so gained facilitate development of better-constrained geological models in subsurface scenarios.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005