RAPPORT

The superficial deposits within the map sheets are discribed and classified according to their genesis. Within map sheet Brattvåg both land and sea areas are mapped. The dominant deposits are tills, marine sediments, weathering material and bogs. The area has been glaciated at least three times during the Weichselian with intervening interstadial periods. The last deglaciation occured some time before 12,300 years B.P., and several moraines were deposited. During Younger Dryas the ice front was situated far to the east of the area, but several cirque moraines were formed within map sheet Brattvåg. The regression was very rapid just after deglaciation and up to 9000 years B.P., but levelled off during Younger Dryas. The Holocene transgression maximum was reached at about 6000-7000 years B.P.

The map-sheet Båtsfjord covers an area belonging geologically to the Barents Sea Region. Two major lithostratigraphic units occur within the confines of the map-sheet: the Lokvikfjellet and the Barents Sea Groups, with the former overlying the latter along an angular unconformity. The age of both groups is Late Proterozoic. The rocks in the area were metamorphosed at a very low grade during the Caledonian orogeny. The tectonic structure of the area is comparatively simple, characterized by Ne-SW trending folds with approximately vertcal axial planes.

The different rock-types within the map-area are discribed. Four tectonostratigraphical elements are recognized: 1. Precambrian crystalline basement; 2. The autochthonous Kinnfokfjellet Formation; 3. The Fortun Nappe; and 4. The Jotun nappe complex. A short account is given on aspects of economic geology of the area.

The superficial deposits occuring within the map-area are described and classified according to their genesis. In the mountains a discontinuous or thin cover of till dominates with peat in the depressions. In the lowland areas glaciomarine sediments were deposited at a sea-level situated c. 155 m above the present one. The deglaciation of this area took place during the Bølling and Allerød chronozones. During the Younger Dryas the glaciers andvanced to the Tautra Moraines, situated some 20 km to the cast of this map-area. This led to an intense calving of the glaciers in the Trondheimsfjord. Drifting icebergs caused a marked increase in the content of coarse-grained rock fragments in the glaciomarine sediments. During the shoreline displacement the sediments below the upper marine limits were influenced by fluvial erosion and slides. Short account are given on the potential for different utilization of the mapped superficial deposits.

Petrographic and structural descriptions are presented of the different rock-types occurring within the area of map-sheet Arstaddal. The area investigated is situated in the Breiarn Nappe Complex in the Caledonides of Nordland. The rocks are divided into five units: Govddestinden Nappe, the Habresåga (Stabben) Nappe, the Sokumfjell Group, the Gråtådalen Group and the Stabbursdalen Group. The data show that there must be significant differences in age between the various units in the map-area and also that the units have different early deformational and metamorphic histories.

The superficial Quaternary deposits occuring within the map-sheet area have been classified and mapped according to their genesis. Fine-grained marine deposits dominates in the main valley below the highest postglacial sea-level. c. 1973 m a.s.l. Numerous glaciofluvially ice-contact deposits are situated in the main valley too, but only the nothernmost was built up to the sea level (true deltas). During the postglacial isostatic uplift, the rivers retransported the glaciofluvial deposits and most of this material was deposited as regression-deltas at lower levels. Above the highest sea level quaternary deposits are almost lacking except for scattered till.
Løsmasse og arealbruk: The utilization and evaluation of the superficial deposits with regards to cultivation, forestry, waste disposal, engineering, groundwater, sand and gravel resources and nature conservation, are discussed. A field trip guide to the area is presented.

The superficial deposits within the map-sheet are described and genetically classified. Tills are the dominating sediments, but considerable amounts of glaciofluvial and fluvial deposits also occur. Slide and talus deposits occur widely in the valleys and weathering material blockfield is present in the higher areas. The oldest described ice striations probably represent a regional ice movement towards the northwest. This northwesterly ice movement was followed by other ice movements controlled mostly by the regional topograph during the folloving deglaciation. During both periods of glaciation diverging striae provide evidence for the existence of local culmination aeras in the mountains within the map-sheet Sunndalsøra. The progress of the moraine ridges in the Reinsvatnet area indicates the existence of an event, the Reinsvatn event. This event is thought to be of Younger Dryas age. The highest marine level during the deglaciation in Sunndalen occurs at some 145 m a.s.l. Radio carbon dating of shells found in glaciomarine clay indicates that Litledalen was deglaciated 9,740±250 C-years B.P.(T-4516).

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.

Investigations of sand and gravel aquifer below the marine limit in Solør, southeastern Norway have shown the following realtionships between the sedimentological and the hydraulic proberties. The thin (1-15m) and fine grained(fine sand, silt) superficial deposits cause the groundwater table to mainly follow the topograhy of the surface and the bedrock. The glaciofluvial sediments, which are interpreted as subaquatic deltas - eskers deposited in front of a calving glacier, have only a small extension. Both the glaciofluvial and the marine sediments are fine grained below the groundwater table, which is only to a small degree affected by the different sediment types. The hydraulic conductivity (k) of the glaciofluvial sediments calculated from grain size distribution has a slightly lower value than k determined by the pumping test. In a general range of hydraulic conductivity the k-values from both methods correspond to the hydraulic conductivity the k-values from both methods correspond to he hydraulic conductivity of pure sand.

The superficial deposits occuring within the map-area are described and classified according to their genesis. In the mountains a discontinuous or thin cover of till dominates with peat in the depressions. In the lowland areas glaciomarine sediments were deposited at a sea-level situated c. 180 m above the present one. In Frosta and Skatval these sediments are overlain by till, deposited by a glacial advance during early Younger Dryas, reaching just to the west of the map-area. Marginal moraines from a late Younger Dryas glacial advance can be traced more or less continuously from Hegra in Stjørdal toowards Hoklingen and Alstahaug. During the shoreline displacement the sediments below the upper marine limit were influenced by fluvial erosion and slides. Short accounts are given on the potential for different utilization of the mapped superficial deposits.