Polish Polar Research

Extensive floors of well-developed ancient trough-like valleys around Petuniabukta were subject to glacial, marine and alterations caused by gravity movements during the Late Pleistocene and Holocene. Palaeogeographical changes took place and are still occurring under the influence of land uplifting movements. The earliest recognizable phase of glaciation occured during the so called Billefjorden Stage about 35.000 to 45.000 years ago. The available evidence suggests that the glaciation was divided into two stages, first the major advance and then, a minor ice advance. This glacial episode was followed by morphological alterations conditioned largely by the action of sea and gravitational factors. About 6.500 years BP a short-term, though rather extensive glacier advance took place and afterwards, the processes of marine morphogenesis recurred. The last notable glaciation phase traced from the land surface can be identified with the Little Ice Age. The Holocene changes in morphology are reflected in extensive outwash plains and a tidal plain.

This article presents characteristics of the Quaternary deposits and landforms of Ebbadalen, the Nordenskióldbreen foreląnd and the Wordiekammen massif on the basis of geomorphological mapping of this area and a number of geologic profiles A—L studied in detail. Glaciers were much more expanded during the Pleistocene than they are nowadays. Over a period referred to by the present authors as the Petuniabukta-Adolfbukta Stage they occupied the whole Ebbadalen area and the eastern part of Adolfbukta. Marine terraces of 70- 80, 60—65 and 50—55 m a.s.l. were formed earlier. At the turn of the Pleistocene three marine terraces were produced at 40—45, 30—35 and 20—25 m a.s.l. Throughout the Early Holocene transgression (the Ebbadalen Stage = the Thomsondalen Stage) glaciers occurred in nearly the entire Ebbadalen area and occupied a larger part of Adolfbukta than nowadays. During the Middle and Late Holocene marine terraces of 12—15, 5—8, 3—4 and 1—2 m a.s.l. were initiated. Two more glacier advances, the later relating to the Little Ice Age, took place during the Late Holocene

Mineralogical and chemical analysis of the glacial deposits of the Petuniabukta region, laid down due to glacial advances occurring from the Billefjorden Stage to the Little Ice Age has been made. The deposits have substantial carbonate contents which, however, vary depending on rock types of which the bedrock is built up. The calcium ion is the main component of the sorption complex of the deposits under investigation. A proportion of other ions, including magnesium, sodium and potassium, is markedly lower. An increase in the magnesium, sodium and potassium ion contents of the sorption complex with age and a concurrent decline in calcium ions have been reported from glacial tills. The illite clay minerals prevail in glacial deposits occurring around Petuniabukta. Apart from them, there are large quantities of the chlorite and kaolinite clay minerals. The glacial deposits of Spitsbergen remain markedly richer in the chlorite group than glacial tills of Poland. Simultaneously, they contain markedly smaller amounts of minerals of the- smectite group and illite/smectite mixed-layer minerals. This is due to a fainter effect of the weathering processes on the glacial deposits of Spitsbergen, compared with the glacial tills of Poland.

In the 1985 ablation season studies were made of the dynamics and size of the transport of suspended and dissolved material in a glaciated drainage basin (the Ebbaelva) and an unglaciated one (the Dynamiskbekken) in the central part of West Spitsbergen island. The dynamics of runoff, the exhaustion of sources of transportable suspended material, hysteretic effects during floods, the share of genetic type of water differing in the mineralisation level and chemical content, as well as the role of rain waters in mobilising soluble salts, are the principal factors of transport dynamics. The extremaly warm ablation season caused the extent of denudation to exceed the estimates made so far.

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.

Observations of the surface of the Petuniabukta tidal flat showed the occurrence of dead forms indicating a relative lowering of the sea level. Under the silt deposits of the tidal flat a gravel-clay series was found to occur. Connecting this series with the glacial till covering the lowest marine terrace and with the erosion pavement in the lowest part of the outwaśh plain gave rise to the hypothesis that there might be a record of glacier oscillation. By dating a sample taken from the gravel series substrate, the age of the oscillation was estimated at less than 6370+/- 120 years BP.

A rich network of bodies of water fed by supraglacial streams has developed in the Hörbyebreen marginal zone due to intensive deglaciation. Most of them are lakelets of 0.1 to 1.0 ha in area and a mean depth of 0.3 to 1.3 m. They developed mainly after 1961. Studies were made of suspended and dissolved sediment concentration, and the ionic composition of the waters of proglacial streams and lakes, followed by an estimate of the balance of the proglacial transport of material. The calculation showed that the total net deposition of mineral material in the marginal zone amounts to 58.45 t per day. which constitutes 56.07 per cent of the total volume transported by proglacial streams. Borings proved sediments deposited in lakes at present to be of little thickness, ranging from 3 to 19 cm. As to litholology, there in a dominance of light-grey silty-clay deposits with a mean grain-size of 5.70 to 6.21 phi, sometimes with thin intercalations of coarse-grained sands and gravels. Chemical analyses shovedthat these deposits contain mostly silicates with small admixtures of Ca and Mg, and that they reflect the geological structure of the area.

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.

Geomorphic relationships characteristic of the region between the Billefjorden and Austfjorden display a high degree of complexity. The relationships result from palaeogeographical changes which took place during the Late Pleistocene and Holocene. A topographic expression is the product of glacial, marine and lacustrine processes. In view of the gathered observational information and the 14C date of 8.120+60 ɣr BP (Gd-1900) provided in 1987 on marine shells found in glacial deposits between Hoglandvatnet and Alandvatnet, inferences can be made as to a large extent of marine processes in the study area during the maior part of the tarlier Holocene.

The main relief features of glacier marginal zones in the region between the Billefjorden and Austfjorden comprise ice-cored moraines, outwash plains and glacial lakes. Characteristics of various types of ice-morainic ridges are given. This article presents examples of outwash fan relief. The results of palaeogeographical analysis serve as the basis for distinguishing between three principal stages of development of glacier morphology and meltwater outflow in the region between the Billefjorden and Austfjorden.

The Hoglandvatnet and Ålandvatnet are genetically associated with the action of a large ice stream issuing from Mittag-Lefflerbreen towards Lomonosovfonna as far nortwards as Austfjorden. The accomplished investigations permit water properties to be described for Hoglandvatnet and Ålandvatnet, as well as the chemical composition of the basin waters to be correlated with lithologic diversity of the surrounding massifs and the composition of glacier water feeding them. Water of Hoglandvatnet has a rather uniform ion composition. It is sulphate-calcium water. Low mineral contents of glacier water and that flowing through crystalline rocks of Framstaken and feeding the basin result in its less marked effect on the Hoglandvatnet water, compared with highly mineralized water of streams issuing from Trikolorfjellet and Tarantellen. Water of Ålandvatnet has a somewhat different quantitative ion composition than that of Hoglandvatnet. It is calcium-sulphate-bicarbonate water which is richer in the bicarbonate ion than the Hoglandvatnet waters. This is most likely due to the influence of bicarbonate water of Ålandelva and glacier water feeding the basin. It can also be the result of a smaller contribution from highly mineralized calcium-sulphate water issuing from Trikolorfjellet.

The present article provides information on the method of distinguishing between spatial natural units within a valley microregion in the Arctic zone. Geocomplexes fall into 20 types and are grouped under four categories of high order units, i.e. glacial, fluvial, slope and polygenetic geocomplexes. The lithomorphogenetic criterion is useful in differentiating other natural characteristics.

The observations made on the Ebbaelva and measurements of water stages and discharge provide the basis of determination of runoff variations and amount for its catchment. The results of simultaneous measurements of suspended sediment load are used for calculating the magnitude of denudation. The present article, whilst covering the above aspects, describes thermal properties of the Petuniabukta waters as well as considers whether inland water can desalt them.

During a month from 28 June till 27 July 1987 measurements were made of variations in the chemical composition of shallow water basins occurring on the north side of the Ebbaelva gap section at the southwestern foot of Lovehovden. The waters have variable mineral contents and ion composition. The resulting data indicate a marked effect of various kinds of water feeding the basin, including water derived from the melting of snow and that released due to permafrost degradation, depending on bedrock and the intensity of biogenic processes which operate in areas of basin occurrence.