The genesis of the Chilean nitrate deposits

Joseph Theophilus Singewald, Benjamin Leroy Miller
1916 Economic Geology and The Bulletin of the Society of Economic Geologists  
existrain other words, the explanations are based on assumptions of greater or less probability. Wit'h such a state of affairs, one man's theory has been about as good as another's, and diversity of opinion still rules on the problem in question. During a brief visit to the nitrate fields of the Province of Tarapac/t last September, the pendulum of interest of the authors of this paper swung to the other extreme; and we were less interested in the how of the formation of the nitrate than we
more » ... nitrate than we were in the manner of distribution of the nitrate deposits and the how of their localixation. We soon had the feeling that the solution of the latter problem carried with it the solution of the former, or, at least, greatly minimized its importance. The particular purpose of this paper is to set forth .our ideas in regard to the localization of the Chilean nitrates, and to discuss their bearing on the general problem of the genesis o.f these deposits. Before doing this we shall state briefly what theories have been advanced to explain them, and summarize some of the arguments for and against them. Most of the theories that are or have been in vogue to account for the Chilean nitrate deposits may be grouped under four headings, according to the manner in which the nitrate is supposed to have been f.ormed. These are: I. The seaweed theories. 2. The guano theories. 3. The bacterial theories. 4. The electrical theories. The sea'weed theory 'was proposed in I867 by Dr. C. N. Noellner. He believed that great quantities of seaweed collected along the portion 'of the west coast paralleled by the nitrate fields, due to the prevailing westerly winds, and that occasional hurricanes piled this up. An uplift of the land or a recession of the sea followed. The sea water that remained behind evaporated and furnished the sodium chloride, while the nitrates resulted from the slow oxidation of the seaweed. The great argument in support of this theory was the presence of iodine in the nitrates. Until iodine was extracted from the mother liquors of the nitrate oficinas, seaweed was the only known source of the el.ement. GENESIS OF CHILEAN NITRATE DEPOSITS. 105
doi:10.2113/gsecongeo.11.2.103 fatcat:jh4xisug7nexdoyrpfazibzoye