1921 . Xn. 



ON THE ECLOGITES OF NORWAY 



3r 



and grains of brown rutile. Apatite seems to be absent. Still an ac- 

 cessory mineral is pyrite that, in the form of minute hexahedrn, is evenly 

 distributed in all the thin sections studied. 



The chloroiiu'/aiiitc-cclogitr of Dum type fro)ii raiirlvsdalcii, Soiidiiiore. 



M. Irgens and Th. Hiortdahl have collected specimens of eclogite 

 marked "Duen, \'an el vsd al en", and manv later describers of the Nor- 

 wegian eclogites have mentioned this occurrence. The present writer 

 found quite similar eclogite near Du es toi in Almklo vdal en (the upper 

 \'anelvsdalenl, and this may be the same locality. Eclogites, mineralogically 

 and structurally identical with the Duen eclogite were found at several 

 places, e.g. Al m klo vsaeter in Almklovdalen and near Tuen in \'an- 

 elvsdalen, and they are very frequent in this tract as erratic boulders. 

 Thus a specimen in the collections of the museum marked "erratic 

 boulder, X'anelvsdalen" was chosen for quantitative study because 

 of the unaltered character of its minerals. Although it is not certain that 

 this specimen has been derived exactly from the Duen or Duestol oc- 

 currence, we may yet designate it as "eclogite of the Duen type". 



The eclogites of the Duen tN'pe occur as lenticular inclusions in gneiss. 



Of the garnet that part was taken that floated in a solution of sp.g. 

 ^^ 4.02 and sank in that of sp.g. == 3-9 7- The analysis of this deep red 

 skarnet was executed bv Mr. L. Thomassen with the following- result: 



100.73 



Sp.g. = 3-99 



"d =" I-79I1 



RÖ., : RoO., : SiO., = 2.85 : i : 2.96 



Composition : lFe5-Mn.2MgigCa25)3( AlgjEcj).,. 



In diluting the Clerici solution the pyroxene just floated when the 

 sp.g. was 3.38. After the removal of all that sank at this degree of dilution 



