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REPORT ON ANTARCTIC SOILS 



Rock weathering under normal conditions consists, first, of the mechanical 

 disintegration of the rock into gravel and sand ; next, the formation of veins of 

 secondary minerals in veins within these grains ; and, lastly, the solution of the secondary 

 minerals in organic acids causing further disintegration. 



Only the first two of these processes are of importance in Antarctic weathering. 

 Consequently the accumulation of zeolites makes the soils appear chemically rich. 



The cause of the absence of the third process lies in the absence of organic acids. 

 Organic matter in these soils is remarkably low. This is due to dearth of plant life, 

 the cause of which I propose to touch upon. 



First, carbon dioxide is much lower in the air of frigid climates than in our climate. 

 Secondly, the cold regions of the earth have no thunderstorms, hence the precipitation 

 is not nitrified with nitric acid as in regions where thunderstorms are frequent. The 

 discharges of the aurora are probably not intense enough to make nitrogen combine 

 with oxygen. The want of the acids C0 2 and HN0 3 partly accounts for the small amount 

 of leaching. The want of nitric acid, together with the coldness of the climate, account 

 for the want of plant life, and hence of organic acids which would dissolve carbonates 

 and zeolites. Nitrifying bacteria, which can produce nitric acid and ammonia from 

 the air, cannot live in the cold, and plants do not thrive in the absence of nitrates. 



The Antarctic soils are alkaline, which fact is due to the accumulation of salts, 

 carbonates, and zeolites, and the absence of organic acids. 



In two of the soils (1 and 2) crystals of Glauber's salt {mirabilite) existed in the 

 dried soil. The soil water is probably charged with this salt, which may probably 

 be derived from the decomposition of nosean in the alkaline lavas. Common salt 

 is also abundantly present, and is in the soils examined partly derived from marine 

 spray, but may partly be formed by the decomposition of sodalite. 



The small percentage of nitrogen obtained in each estimation probably exists in the 

 form of ammonia salt from wind-blown penguin guano, or droppings from skua gulls. 



