The application of GIS to unravel patterns of deformation in high grade terrains: a case study of indentor tectonics from west Greenland

Abstract

The ability to compare, integrate and knit together multidisciplinary datasets in terms of subject, space and scale is critical to the recognition of geological patterns. In this contribution, we show that the use of Geographic Information Systems (GIS) is extremely valuable in detecting patterns associated with broad zones of deformation in high grade terrains. The GIS methodology facilitates the geological interpretation and development of models as it permits an easy and quick investigation of several geoscientific datasets by subject, space and scale. The GIS-based integration of structural, metamorphic, fabric type and aeromagnetic datasets collected in west Greenland shows that patterns seen within one dataset coincide with patterns observed in other datasets. Consequently, two major domains are recognized that are separated by a broad boundary zone. The southern block is characterized by a distinct, irregular magnetic signal coupled with granulite facies metamorphism and dominant S-type fabrics. The map scale geometry of this block controls the patterns observed within the amphibolite facies domain further north. Foliation and lineation patterns form an arcuate swing in strike about the southern block. Fabric types vary both around the strike swing and across strike. An indentor model that incorporates a rigid, cooled granulite block in the south bounded to the north by a theologically weaker amphibolite facies domain can explain these patterns. The preserved metamorphic grade governs the theology of the different, but essentially authochthonous blocks with the amphibolite facies domain being plastered and 'moulded around' the rigid granulite indentor.

Complex fault patterns, transtension and structural segmentation of the Lofoten Ridge, Norwegian margin: Using digital mapping to link onshore and offshore geology

“…[7] In the present study, we apply new digital mapping workflows [Jones et al, 2004;Wilson et al, 2005;McCaffrey et al, 2005] to construct a structural database for both onshore and offshore structures on the Lofoten-Vesterålen archipelago (LVA; Figure 2c). All data are stored digitally in a Geographic Information System (GIS) database that facilitates the interpretation of multiple/integrated data sets (e.g., seismic data, remote sensing, field mapping [Jones et al, 2004;Piazolo et al, 2004]). It also provides an ability to analyze structures spatially across a wide range of scales.…”

Relationships between magnetic and structural fabrics revealed by Variscan basement rocks subjected to heterogeneous deformation—a case study from the Kłodzko Metamorphic Complex, Central Sudetes, Poland

“…Therefore, in such terrains analysis of the finite fabric, which is the result of the bulk deformation, becomes the most useful method of recognizing significant patterns in regional deformation (Piazolo et al 2004). Our results show that AMS study provides a useful tool for the generalization of a structural pattern.…”

Recording and analyzing geospatially accurate structural data through ‘digital mapping’ technique: A case study from the Canisp Shear Zone, NW Scotland

“…Piazolo et al (2004) carried out a similar type of analysis at the regional scale to define crustal-scale reworking fronts in the Nagssugtoquidian orogen in West Greenland. Our database was much more limited both in scale and sizetypically we had 100-150 meansurements distributed sparsely across the CSZ.…”

“…These include rose diagram tools and stereonet plotting tools such as GIS-Stereoplot (Knox-Robinson and Gardoll, 1998). Piazolo et al (2004) have integrated geological and geophysical datasets in a GIS to define the shapes and patterns of structural domains at a variety of scales in the northern Nagssugtoquidian orogen, west Greenland.…”