424 Olaf Holtedahl — Geology of N. W. Spitsbergen. 



ing to the moraines of the glaciers of the Ice Age. The 

 second volcanic cone is situated near the top of a mountain 

 ridge farther to the south, and is much more dissected. 



Additional evidence indicating instability along this same 

 fault line is the presence of a large number of warm springs, 

 with a maximum temperature of 29° Celsius, many of which 

 have built up beautiful basins of carbonate of lime. 



Covering all the higher part of the southern area of the 

 peninsula between Wood Bay and Wijde Bay occurs another 

 kind of volcanic rock. Here we find thick beds of basaltic 

 lavas, often with a wonderfully well-developed columnar struc- 

 ture. Regarding the age of these rocks, their petrologic rela- 

 tion to the well-known Cretaceous or early Tertiary diabases 

 of Spitzbergen may indicate synch roneity with the latter. 

 Assuming a Tertiary age, we would also have contemporaneity 

 with the basaltic rocks of the other north Atlantic countries. 

 The physiographic features of the lava region also suggest a 

 rather young age. We may for very long distances walk on 

 the quite plane and smooth lava surface, as if the igneous 

 material had flowed out only a short time ago. Yet we find a 

 great number of ice-eroded valleys cutting through the lavas 

 and far beneath them, showing that the lava must be older 

 than the time of greater ice distribution, since at present the 

 region is almost barren of glaciers. It seems, however, as if 

 this lava land had not been at any time wholly ice-covered, as 

 we know Spitzbergen in general has been. 



The lava lies on an ideally plane surface, cut in the folded 

 Devonian rocks. Probably the outflow took place when this 

 surface was at, or near, sea-level, and later the whole region 

 was uplifted, at the north end of the peninsula only 300-400 m., 

 at the southern 1200-1300 m. 



University of Kristiania, October, 1913. 



