ABOUT LITHODYNAMICAL PROCESSES ALONG THE KOLA FIORD COAST OF THE BARENTS SEA

Abstract

This article is devoted to the study of the basic laws of the formation, structure, mor­phology and composition of sediments of accumulative landforms at the mouths of small rivers on the northern (fjord) coast of the Kola Peninsula washed by the Barents Sea waters. Along the northern Kola fjord Coast of Barentz Sea, the development peculiarities of lithodynamical processes are geographical location, expansion of old strong rocks with slowly rates of cliffs retreat and with severe hydrodynamical re­gime. As a result of this alongshore drift flows cannot develop. Normal exchange by sediment with adjoining regions of a sea shores are absent. Abrasive-denudation process is dominant, and it intensifies the sediment deficit within narrow coastal zone of the Sea. In addition, coastal deposition of the shore origin is unlikely along the entire distance by absolute Murmansk shoreline. The main reason is the strong impact of water dynamic and very steep shelf slope. They throw off sedimentary material to deep bottom without sphere of positive waves (surf) impulse for big debris of local rocks. That is why within the Northern coast of the Kola Peninsula the most important lithodynamical action all time were separate hearth’s sites of deposition and short flows of migration. All time the fiord tops have location of sediment debris which undergo wave rubbing, and during sea-ice time discard shore sediment take place. A detailed analysis in the mouths of the Teriberka, Voronya and Kharlovka rivers where modern sandy terraces of the coastal-marine genesis lie have been carried out. It was noticed that the influenced of strong igneous and crystallized rocks and active phys­ical weathering after the fast melting of snow from the catchment area carries away fine-grained material into the rivers (fractions ≤ 3 mm). These materials which are composed mainly of Alluvials leads to the construction of terraces. The productive vector of the wind flow on the coast with an average long-term wind speed ≈ 8 m/s is directed from land to sea. The smallest sediments are blown into the sea from the surface of the terraces. In contrast to the eastern shores of the Barents and White Seas, these sediments form sandy tidal dehydrations. Silt debris composed of fine-grained material of (fractions ≤ 1 mm) dominates here. The main part of alluvium ≥ 1.0 mm is retained in river channels. It should be noted that on the studied coast, an average of 15.36% of these fractions erupt into the composition of coastal terraces. The smallest debris and part of the sand goes down to a depth along steep underwater slope (up to i10 ≤ 0,15). On the frontal surface slope of the terraces, fractions of 1.0-0.25 mm on the beach dominate (of which the content is 0.5-1.0 mm = 38.93%). All sand fractions account for 88.78%, including coastal dunes. The dune relief forms are small and are in the germinal state. They are characteristics of the mouths of the rivers where they exist.