Mica-quartziU 



IT. AKADEMIENS UANDL1NGAH. BAND 29. \:n 4. L15 



nica srliisi 

 [uarfczite 

 j mica schisl with conglomerate 

 t quartzite with iron ore. 



I black hornblende-bearing dense fine-grained gneiss 

 Dense fine-grained gneiss \ gray denjse fine-grained gneiss with layers of mica schists. 

 I gray gneiss, less fine-grained. 



The overlying Klagstorp- and Dyneboda-gneisses were considered as belonging to 

 the great magnetite-gneiss-forrnation, that oeeupies most of south-western Sweden. 



In the underlying gneiss there occur two younger granites, and the gneiss in their 

 vieinity beeomes less fine-grained. 



Probably older than the gneisses is the granite-gneiss, occupying the south-western 

 and southern part of the district. 



In the following we shall deal with the different rocks separately and begin with 

 the youngest; we shall thus treat first the granites, second the quartzites, third the amphi- 

 bolites, and fourth the dense fine-grained gneiss and the fine grained gneiss into which 

 it passes, then the mica schists interbedded in the gneisses; then after following the gneisses 

 to the east, and then to the north, we will study the Klagstorp- and Djmeboda-gneisses, 

 occurring on the western side of the quartzite band. Finally the remaining genetically 

 niore or less differing gneisses of the district are treated, and at last some general re- 

 marks given. 



Granites. 



As shown by the map, plate 1, and the map on p. 110 granites occur in numerous 

 great and small massives seattered in the gneiss. These may be considered as out-posts 

 of the great granite district of south-eastern Sweden. They are all younger than the gneisses, 

 their relation to them will be dealt with låter on. — Of these granites there is one cha- 

 racteristic, fine-grained type which occurs spread över the whole of Blekinge, known as the 

 »Hälen»- or »Spinkamåla»-granite; among the others, one is coarse-grained, the »Jemshög»- 

 granite and also the related »Karlshamn»-granite. Both these types occur in the region 

 studied more in detail in this paper. 



The »Jemshög»- and the »Halen»-granite are closely related mineralogically and 

 structurally, with the exception that the former is coarse-grained. Characteristic for both 

 is the scarceness of the ferro-magnesian minerals and the predominance of microcline and 

 quartz över the oligoclase. Allanite and titanite are constant and often macroscopic con- 

 stituents. Hornblende never occurs, only biotite. — The chemical composition of the fine- 

 grained granite from the eastern shore of Lake Raslången is 



Si0 2 Ti0 2 A1. 2 3 Fe 2 3 FeO MnO MgO CaO Na 2 K 2 H 2 Sum. 



73,38 0,20 14,36 0,86 0,79 0,22 0,46 1,33 2,85 4,98 0,37 99,80 



corresponding to 34,2 quartz, 27,9 microcline, 24,2 albite and 6,6 anorthite (or 30,8 Ab^AnJ, 

 3,7 biotite, 1,2 magnetite. 



