Pierpaolo Guarnieri

From oblique photogrammetry to a 3D model - Structural modeling of Kilen, eastern North Greenland

We present a workflow for building 3D geological models from oblique photogrammetry of outcrops. The workflow is used to build a 3D model of Kilen, a structurally complex and remotely located pseudo-nunatak in eastern North Greenland. The area was visited during two brief field seasons during which 1300 oblique photographs were taken by a hand held digital camera from a helicopter. The photos were triangulated and georeferenced and visible geological features as bedding and faults were mapped as 3D polylines. The polylines were used to calculate strike and dip of bedding and faults, generating a large number of structural information. These were imported into a 3D modeling software along with the 3D polylines, an unpublished digitized field map, a Digital Elevation Model, an orthophoto and georeferenced field observations. The 3D modeling software allows us to produce 2D cross-sections and 3D surfaces so that structural hypotheses could be tested through restoration and extrapolation of the data. This workflow proved effective in improving the structural knowledge of a remote area in the Arctic, showing that it is possible to produce quality 3D data from oblique photogrammetry and that those data can be used for 3D modeling. We present a workflow for making a 3D geological model from oblique photogrammetry.The workflow is used to build a 3D model of a structurally complex area.The workflow greatly helped improve the structural knowledge of the area.

Tectonic inversion in the Wandel Sea Basin: A new structural model of Kilen (eastern North Greenland)

The seminunatak Kilen in eastern North Greenland, with its complexly deformed Carboniferous-Cretaceous strata, is a key area to understand the tectonic history of the transform plate boundary between eastern North Greenland and Svalbard. Detailed 3-D geological mapping from oblique photogrammetry along with limited ground fieldwork and interpretation of previously published data forms the basis for a new structural model of Kilen. Previous structural models interpreted rhombic-shaped fault patterns as the evidence for strike-slip tectonics. These structures are here interpreted to be the result of a post-Coniacian NE-SW extension with NW-SE trending normal faults followed by later, N-S compression of presumable Paleocene-Eocene age, folding the faults passively and suggesting the presence of a basal detachment. Furthermore, two thrust sheets have been distinguished on Kilen: a lower Kilen Thrust Sheet and an upper Hondal Elv Thrust Sheet separated by a subhorizontal fault: the Central Detachment. The style of deformation and the structures described are interpreted as the result of Paleocene-Eocene N-S directed compression resulting in basin inversion with strike-slip faults only having minor status. This indicates that the Greenland margin as exposed on Kilen and the conjugate Svalbard margin in the West Spitsbergen fold-and-thrust belt are more similar than previously anticipated.

Geometry and kinematics of the Triassic rift basin in Jameson Land (East Greenland)

The Triassic rift basin along the East Greenland margin described in this paper is represented by NE—SW trending basins and highs segmented by NW—SE trending transfer zones. Coarse grained sediments along the eastern side of Jameson Land are shown to be hosted in half-graben structures belonging to the Carlsberg Fjord Basin that is bounded by NW-dipping normal faults mapped and described after fieldwork in the Klitdal area in Liverpool Land. New aeromagnetic and electromagnetic data together with new drill cores allow the re-interpretation of available seismic lines showing the continuation of the Triassic rift basin toward the SW where it is buried under the Upper Triassic post-rift sediments and the Jurassic successions of the Jameson Land Basin. The N—S trending Liverpool Land, interpreted as the boundary block of the Triassic basin, is shown to represent a structural high inherited from the Late Carboniferous tectonics and faulted during the Triassic rifting. The Carlsberg Fjord Basin and the Klitdal Fault System described in this paper should be seen as analogues to the Helgeland Basin in the Norwegian offshore that is bounded by the Ylvingen Fault Zone and to the Papa and West of Shetlands Basins that are bounded by the Spine Fault. The Triassic rift zone and transfer faults on both conjugate margins shows a straightforward correlation with the trends of the initial spreading line and fracture zones of the North-East Atlantic indicating a possible inheritance of the Triassic rifting.

CRUSMID-3D : Crustal Structure and Mineral Deposit Systems: 3D-modelling of base metal mineralization in Jameson Land (East Greenland)

Providing research and education at a high international level is a prerequisite for the raw material sector to develop competitive and cost effective exploration methods. The NordMin project CRUSD ...

Geological Analysis of Aeromagnetic Data over the Blyklippen Lead-zinc Mine at Mesters Vig, Central East Greenland

In the Mesters Vig area epithermal Pb-Zn sulphide-bearing quartz veins are associated with the border faults of a NNW-SSE elongated graben down-faulting Carboniferous to Lower Triassic sediments. The analysis of the total magnetic field, tilt derivative, vertical derivative and analytic signal allowed to define subcropping magnetic domains and identify structural trends. Doleritic dykes, sills and faults were mapped and structural relationships were established between them. Finally, aeromagnetic data allowed here to delineate structural trends along and in the vicinity of which mineralized quartz veins are mapped.