14 



MARTIN SCHWARZBACH 



paleomagnetic results as well as with paleoclimatic reconstructions in other 

 continents. The climatic map of Devonian time which I published some time 

 ago may illustrate this problem (see also Fig. 1). 



Recent climatic 

 zones 



polar 



temperate 



sub- 

 tropical 



tropical 



^ 





500 

 P a 



1 e o 



200 100 



Mesozoic 



million /s. BP 



Cenozoic 



Fig. 1. The climatic position of Iceland, according to geological results, during 

 the last 600 million years. Only the recent position (shown in black) is definite, all 

 others are more or less hypothetical, and more so the farther back we go into the 

 past. Paleomagnetic data were not used in the construction of the figure. The 

 shifting position may be due (especially in the Paleozoic time) in part to continental 

 drift. Design by Dr. L. Ahorner. 



4. TERTIARY 



There is no sharp boundary between the Mesozoic and the Tertiary, a 

 period which lasted from ca. 70 to 1 million years B.P. At least in the Lower 

 Tertiary we find climatic conditions similar to those in the Cretaceous and 

 the temperatures of high latitudes were much higher than today. There 

 existed no polar ice caps, but instead rich tree vegetation even on the islands 

 nearest the pole. 



Nevertheless we will consider the Tertiary separately; first, because the 

 climate changed decisively in the younger Tertiary; second, because we now 

 have much more and better climatic indicators, also from Iceland, as 1 

 mentioned earlier. 



The Tertiary tree floras of Iceland were the very first to be known, for as 

 early as in 1772 (190 years ago), Eggert Olafsson from Iceland carefully 

 described the plant impressions of Brjanslaekur in northwestern Iceland. 

 Afterwards many other polar floras were discovered. ''Polar flora" means all 



