The largest glacier of the Petuniabukta area is the Hörbyebreen. It is among the tew on Spitsbergen whose marginal zones undergo areal decay. What has made in this type of glacier is a rich supra-glacial moraine cover that was formed as a result of a deformation of debris bands in the frontal part following a surge. In the marginal zone three subzones were distinguished differing in the degree of degradation of passive ice that covers almost all its area. They also differ in the stability of deposits and in the relief.
At the outlet of the Hörbyedalen, at the footslope of Gizehfjellet, lies a fragment of a raised marine terrace of an altitude of 45 m above sea-level. It is undercut by a proglacial river constituting an exposure with a series of marine, fluvio-glacial and moraine deposits. A lithological characterisation of the deposits was carried out, and radiocarbon dating and TL analysis were used in an attempt to present the chronostratigraphy and development of glacial and marine events in the Hörbyebreen during the Vistulian and the Holocene.