CEMENTATION. 681 



zone of anamorphism to the belt of cementation (see pp. 665-667), and takes 

 with it the freed materials and all the other compounds it can hold. Hence, 

 under normal conditions, solution probably somewhat overbalances deposi- 

 tion; bat where igneous instrusions occur the above reasoning is 

 inapplicable. 



RESULTANT PROCESSES. 



The processes resulting from the chemical changes comprise cementa- 

 tion and metasomatism. 



CEMENTATION. 



Cementation in the zone of anamorphism is of far less importance 

 quantitatively than in the belt of cementation. The openings are mainly 

 confined to those of microscopic size — -i. e., to the capillary openings 

 between the mineral particles and to the innumerable subcapillary open- 

 ings. There are in this zone no large openings. The laws of deposition 

 within the minute openings are the same as in the belt of cementation, and 

 will therefore not be repeated. However, the minerals produced are those 

 characteristic of the zone of anamorphism rather than those of katamorphism. 



The list of these minerals is deferred to the next section on metasoma- 

 tism, since that process is far more important than cementation. While 

 the quantity of cementing material in the zone of anamorphism is small, 

 it is not unimportant, at least so far as the strength of the rocks is 

 concerned. If after deformation the new openings between the particles 

 were not occupied by mineral material, the rocks would be rather weak. 

 When, however, these particles are cemented by deposition, they may 

 become as strong as or stronger than they were before deformation. 



That cementation actually does take place in the minute openings 

 between the grains is shown by the experimental work of Adams. When 

 marble was deformed without water the modified rock was weaker than 

 the original marble, but where water was present, under great pressures 

 and at high temperatures, in one case the deformed rock was actually 

 stronger than the original marble, thus showing that cementation caused 

 the grains to cohere more strongly than when simple welding was the 

 cause of cohesion, as in the case of deformation where water was absent. a 



a Adams, F. D., and Mcolson, J. T., An experimental investigation into the flow of marble: 

 Philos. Trans. Royal Soc. London, ser. a, vol. 195, 1901, pp. 370-385. 



