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.
Highlights
Area and accessibilityThe area described in this report, roughly covering 800 km2, was mapped during July and August 1970 as part of the five year series of expeditions to the Scoresby Sund region of East Greenland carried out by the Geological Survey of Greenland (Henriksen & Higgins 1969, 1970, 1971).The area is formed by a group of nunataks and lies WNW of Harefjord and Rypefjord, inner Scoresby Sund region, between 71 ° 00' and 71 ° 22' N and 28° 30' and 30° 30' W.The larger nunataks, to the east, are mountainous with moraine covered plains and small ice-caps
Observations made during field-work and during study of the samples led to the division of the rock types in this area into four structural units; an autochthonous basement and cover sequence overlain by three thrust masses
The leucocratic gneiss and amphibolite may well represent an older infracrustal sequence upon which the sediments metamorphosed into the rusty brown gneiss were deposited
Summary
The area described in this report, roughly covering 800 km, was mapped during July and August 1970 as part of the five year series of expeditions to the Scoresby Sund region of East Greenland carried out by the Geological Survey of Greenland (Henriksen & Higgins 1969, 1970, 1971). Leucocratic gneiss and amphibolite: basement rocks associated with the rusty brown gneises These may be divided into two distinct cover sequences, the ferruginous quartzite series and the chlorite schist series forming the first, the rusty mica schists and the rusty brown gneiss forming the second. The chlorite schist series, the rusty mica schists and the rusty brown gneiss, together with their associated infracrustal rocks, have been superposed by thrusting in a westerly direction and overlie the ferruginous quartzite series, the metavo1canics and certain infracrustal rocks, which may well be autochthonous. The exposure of this series is extremely limited, being restricted to a small outcrop on the south-east flank of Vindue Nunatak, on the edge of Vindue Gletscher.
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