KARTLEGGING

The map gives a total evaluation of the water yield capacity from the best aguifers, either bedrock or superficial deposits, marked by colours from yellow to bluish green. The map also deicts topography, bedrock geology, constructions and surface hydrology. In the Precambrian rock, major joints along N 30°, N 120° and partly N 0°, N 40° and N 160° trends are considered to be best. The water yield capacities of the different Precambrian rocks and the Drammengranite, which together occupy almost the entire map area, are very much the same, except for the amphibolites and metagabbros which yield less than half of the others.

The superficial deposits and their morphological features within the area of map-sheet Nordfjordeid, western Norway, are classified and described. Ice movements and the course of the deglaciation are reconstructed. The oldest ice movements had a flow direction towards N and NNW almost independent of the underlying topography. Younger ice movements were directed by the fiords and valleys with flow directions mainly towards W. The deglaciation of the area took place in Allerød and Younger Dryas (11,800-10,000 B.P.), interrupted by two readvances: the Vardehaug moraines (10,700-10,600 B.P.) and the Nor moraines (10,500-10,000 B.P.). Outside the area covered by the inland ice cirque glaciers and glacier caps developed in Y. Dryas, indicating a glacial level limit 650 m lower than today. The Nor level is the most distinct marine level in the area having a dip of 1,4 m/km towards WNW. Tills are subdivided according to thickness and occur mostly where metwater reached the sea at the time of deposition, c. 40-70 m a.s.l. Fluvial deposits are found along rivers and mainly as reworked glaciofluvium in the area between the glaciofluvial deposits and the present sea-level. Marine deposits, mainly found in Eidsdalen and along the sides of the fiords, are deposited in areas which were submerged during the deglaciation. Weathered material is present mainly in areas higher than 1000 m a.s.l. Fluvial deposits are found along rivers and mainly as reworked glaciofluvium in the area between the glaciofluvial deposits and the present sea-level. Marine deposits, mainly found in Eidsdalen and along the sides of the fiords, are deposited in areas which were submerged during the deglaciation. Weathered material is present mainly in areas higher than 1000 m a.s.l., and rapid mass-movement deposits found at the base of the steep hills and valley sides.

The superficial deposits occurring within the area covered by the map-sheets are classified genetically and described. Most of the deposits are tills covering wide areas in the southeast, where there are also many deposits of glaciofluvial origin. Fluvial deposits are deposited mainly in the Jakobselva valley, along the Russian border. Along the shore there are few superficial deposits, except for small marine deposits. Brief descriptions are given of the lithology and grain-size distribution of all the superficial deposits. A model for the sequence of geological events during the Quaternary era is proposed based on earlier work and recent field mapping. It is suggested that the deglaciation of the coastal area of Sør-Varanger took place about 12,500 - 10,000 years B.P.

The superficial deposits within the map-sheet Kilebygd, southeastern Norway, are classified and described. Most of the area is dominated by exposed bedrock or a thin and discontinuous cover ot till. In the Nordsjø-Vollsfjorden and Skien basins, below the marine limit(c. 145 m a.s.l), fine-grained marine sediments dominate. A large glacifluvial deposit, Geiteryggen, exists at the eastern end of Nordsjø. Ice movements and the course of deglaciation are constructed. The oldest ice movement was towards SSE, later turning towards SE and ESE. Features associated with glacial events marking small advances or halts of the ice-front during the deglaciation in late Younger Dryas and early Preboreal time have been detected within the map-area. The Geiteryggen frontal deposit with the Ski Moraine in the Oslofjord region and dated to c. 10,000 years B.P. The mapped area was ice-free about 9,850-9,900 years B.P. Short accounts are given on shorelines, shorelevel displacement and pollen analysis. The potential for different utilization of the superficial deposits is also briefly discussed.

The superficial deposits ocurring within the map-sheet area are classified according to their genesis and described. Till is the dominationg sediment, but considerable glacifluvial deposits also occur. Glacier movement directions have been recounstructed in eight phases and subphases. The three youngest subphases correlate with events during the deglaciation. The older phases are considered to span most of Weichselian time. Of the eight glacial events known form the Porsangerfjord area, four occur within the map-area: the Repparfjord event (Older Dryas?), the Gaissa and the Main events (mainly Younger Dryas?) and the Rotnes event (early Preboral?). Extensive deposits, mainly glacifluvial, are related to the Main event. Radiocarbon datings are lacking and suggested ages are based on correlation with dated events in Troms.

The superficial deposits occurring within the area of this map-sheet are classified according to their genesis and described. Based on glacial striae and till stratigraphy 3-4 regional and one (youngest) local icemovement directions are reconstructed. During deglaciation the meltwater was ice-directed. Three phases in the deglaciation are distinguished on the basis of changing meltwater drainage routes.

The superficial deposits within the area of the map-sheet Askvoll, in western Norway are classified and described. Ice movements and the course of deglaciation are reconstructed. The thin and discontinous cover of till and the weathering material are the most extensive deposits in the area. The bogs and the marine deposits are of some economic importance, being used for cultivation. Two glaciation phases are reconstructed on the basis of glacial striae. Ice movement during the older phase was towards the west; this must have been of the pre-Younger Dryas age. The younger phase corresponds well with the Younger Dryas end moraines. Grain-size and lithological analyses have been carried out on the superficial deposits. The tills are dominated by material from the local bedrock, and their predominant grain sizes are those of sand and gravel. Geochemical analyses have also been carried out on superficial deposits.

The superficial deposits within the map-sheet Nordatugu, southeastern Norway, are classified and described. Most of the mountainous areas are dominated by exposed bedrock or a thin and discontinuous cover of till. In the main valleys, below the marine limit (c. 150 m a.s.l.) fine-grained marine sediments dominate. Large glaciofluvial deposits exist in the valley of Saua, north of Nordsjø. Chemical analyses have been carried out on samples from the superficial deposits. Ice movements and the course of deglaciation have been reconstructed. The oldest ice movement was towards the south, later turning towards SE and ESE. During the deglaciation of the mapped are, there were three glacial events marking advances or halts of the ice-front. The Geitryggen event is correlated with the deposition of the Ski Moraine in the Osdlofjord region and dated to c. 10 000 years B.P. Most of the Nordagutu area was still covered by ice at this time. The younger Akkerhaugen and Nordagutu events have been dated to c. 9800-9750 years B.P., respectively. Short accounts are given on shorelines, shorelevel displacement and pollen analyses. The potential for different utilization of the superficial deposits is also briefly discussed.

The map-sheet Bjøllådal, 2028 II, covers a part of the area of a Quaternary mapping programme carried out by NGU in the Saltfjellet district of Nordland. The superficial deposits are classified according to their genesis, and described. The directions of ice movements have been reconstructed mainly on the basis of glacial striae and drumlins, and the course of deglaciation established based on ice movements, marginal moraines, meltwater and the distribution of glacial deposits. The ice movements can be divided intor three main phases: 1) The oldest observed movement direction, towards the west. 2) A younger movement directed towards the northwest. 3) At the end of the deglaciation all the high mountains were ice-free, but glacier tongues flowing from the inland ice further east still occupied the valleys. During the deglaciation c. 9000 yrs. B.P. there were readvances of the inland ice, each one depositing marginal moraines, glaciofluvial and glacio- lacustrine deposits. At the end of the deglaciation extensive ice-dammed lakes developed, especially in Bjøllådalen where ice movements and meltwater drainage were directed towards the north, opposite to the present drainage of Bjøllådalen. The last ice remnants were located in the main valley. Dunderlandsdalen were the ice front receded towards the east. Till is the most common deposit, thick deposits occurring mainly in the valleys.

The main tectonostratigraphic units within the Melvær and Askvoll map-areas are: Precambrian basement rocks, allochthonous Precambrian charnokitic- mangeretic rocks of the Dalsfjord Nappe; allochthonous mainly Cambro-Silurian rocks of the Stavfjord Nappe; Devonian sedimentarty rocks. A description of the different rock types are given. Brief descriptions are also given of the tectonic structures occurring in the area and of the metamorphism of the different units. The Dalsfjord Nappe was thrust towards the south-east, probably in Early Ordovician time, and was strongly eroded before thrusting of the Stavfjord Nappe took place in the Late Silurian. The Stavfjord Nappe was thrust towards the south-east as a major asymmetric anticline - the Stavfjord Anticline - with an axial plane dipping about 40 degrees towards the north-west. A general description is given of some ore and building- stone occurrences.