100 X 10"" - 



(a) 



10 - 



10 X 10"^ N 



Fig. 34. Influence of origin and diagenesis on the composition of organic matter (a) in 

 sediment cores with location shown in (b). The distribution is based on approximately 

 2000 analyses. The envelopes in (a) enclose the central 90% of the total number of 

 samples from the respective areas. (After Arrhenius, 1952.) 



