Structural and lithological divisions of the western border of the East Greenland Caledonides in the Scoresby Sund region between 71°00' and 71°22'N

Abstract

The area described lies on the western border of the East Greenland Caledonian fold beIt in the Scoresby Sund region. The lithological divisions distinguished during field-work comprise a probably autochthonous basement and cover sequence overlain by three thrust masses. Each thrust mass comprises supracrustal and 'infracrustal rocks". Structural complexity and metamorphic grade increase upwards from the autochthon through the thrust masses. This is the resuIt of thrusting of each allochthonous unit from a relatively more internal part of the fold belt; the highest thrust mass of the pile has the most internal origin. Metamorphism and main deformation date from the Caledonian orogeny. Subsequent major normal fauIts have given the area a block structure, bringing different units into juxtaposition. The rock types described may be divided into two cover sequences with associated infracrustal rocks in each case. It appears that both cover sequences may be representative of a single or several closely related sedimentary basins. The depositional age of these sediments is not known, but new age dates reported elsewhere suggest that some of them may have been metamorphosed before the Caledonian orogeny.