Tectonic Evolution of the Prøven Igneous Complex within the Rinkian
Fold-Thrust Belt, West Greenland: Investigation using 3D
Photogrammetry

Abstract

The amalgamation of cratons and subduction of oceanic lithosphere in the Paleoproterozoic
has formed linear orogenic belts worldwide, such as the little studied Rinkian fold-thrust belt
on the west coast of Greenland. The Rinkian comprises a Paleoproterozoic shelf sequence
formed on the margin of the Rae craton that was deformed by basement-core nappes in a highgrade deformation event at c. 1.82Ga. The northern part of the area affected by the Rinkian
fold-thrust belt includes the Prøven Igneous Complex (PIC), a ca. 90 x 80 km large intrusive
complex of orthopyroxene-bearing monzogranite to quartz monzonite, which was intruded
between ca 1.87-1.9 Ga. The PIC was previously considered to be a syntectonic intrusion, so
new work on the structural evolution is important. Here I use detailed photogrammetric
mapping on 3D Stereo Blend at the GEUS Photogeological Laboratory in Copenhagen,
combined with previous survey work, to identify the major deformation phases of the PIC and
their associated structures. We found that the PIC formed as a large sheet intrusion which has
been deformed by a westward verging thrust system, developing type II interference fold
patterns. This is especially prevalent at the base PIC-metasediment contact, where incompetent
rock – partially molten paragneisses and leucogranites – have resulted in more intense top to
the west directed deformation. Furthermore, within the main PIC competent body a type I
interference fold pattern has developed. Our results demonstrate that the PIC was likely
emplaced in situ at shallow crustal levels, and then deformed by the Rinkian orogenic belt. This
study has provided new insights into the deformation history of the Prøven Igneous Complex
and the tectonic setting for the Rinkian fold-thrust belt overall. Furthermore, the project shows
how remote mapping through photogrammetry can cover large areas in revealing detail.