An integrated approach to the study of glaciolacustrine landforms and sediments: a case study from Hagavatn, Iceland

This paper describes the landform assemblage associated with the Neoglacial fluctuation of Hagafellsjokull Eystri into proglacial Hagavatn, Iceland. This landform assemblage is dominated by three components. Firstly, a series of moraines formed both by thrusting within the glacier margin and by proglacial/subglacial deformation. The internal sedimentary architecture of these moraines ranges from stacked sediment slabs separated by listric thrusts to complexly folded and faulted sequences, all in glaciolacustrine sediments. The second component is a morainal-bank and associated ice-contact delta. The morainal-bank consists of a series of low-amplitude ridges composed of laminated silts and claps which have been deformed proglacially during the Neoglacial ice advance (1890). This morainal-bank helped stabilise the 1890 ice limit within the proglacial lake and was the focus for subaqueous outwash, first in the form of a subaqueous out wash fan and subsequently as an ice-contact delta. The third component is a series of lake bed kame terraces formed by rapid sedimentation in a canal-like lake, formed as the ice retreated away from the push moraines. A range of glaciolacustrine facies is present within the lake bed kame terraces and the sedimentary architecture records a complex pattern of ice-marginal oscillations and changes in lake level. This detailed case study provides an important analogue for the interpretation of both glaciolacustrine and glaciomarine landform/sediment assemblages of Pleistocene age and illustrates a range of styles of glaciolacustrine sedimentation and glaciotectonic deformation. (C) 2000 Elsevier Science Ltd. All rights reserved.