A preliminary description of the Klokken intrusion, South Greenland

Abstract

Klokken is a small (3 x 2 km), Gardar igneous complex at 60°56'N, 45°05'W.The intrusion is oval in form and the rock types are arranged in almost perfectly concentric fashion, an outer ring of gabbro giving way inwards via syenogabbros and basic syenites to a strikingly layered body of syenite. Quartz occurs in droses and in aplites and pegmatites, so that although the complex lies only 1 km south of the Igaliko nepheline syenites (Emeleus & Harry, 1970), it is oversaturated and should not be regarded as a satellite of Igaliko. Klokken was visited in 1959 and 1960 by K. Ellitsgaard-Rasmussen in whose field notes many of the observations presented here may be found. The object of the 1971 field work was to obtain comprehensive specimen coverage, to look closely at the remarkable field relations and to extend the detail of the mapping. The complex has sharp contacts with the surrounding Julianehåb granite and the existence of substantial protrusions, roof pendants and rotated xenoliths of country rock can be demonstrated. Hornfelsing and local mobilisation of the country rock has occurred.