Mohave County miner., 1915-03-27
Newer Theories
 of Ore Deposition
After Research We'll Known Engineer Reaffirms the
 Old Established Theory

w HCu CtlC 1HCCIIldIlOHdl NCOlOSlSoi Congress assembled in Berlin in 1885 it was raining furiously. The minister of the interior welcomed the delegates with these words: '"To members of your calling, in which water plays so large part, need make no apologies for the weather" It is the universal experience that we cannot discuss the deposition of ores without calling upon water as the chief agent in the process. We learn that Agricola believed the veins to be formed by what he called the juice of the earth. He did not specify its particular source, but his views were evidently not very far from those held by many today. One of our own phrases is, the juice of the magma.
 Whenever we discuss the formation of veins, the idea of solutions of some sort is necessary. In the early fifties the distinguished French geologist Ellie de Beaumont prepared paper upon the connection between ore deposits and
 
 that emissions from igneous rocks were not without their decided importance, but his views attracted little attention and were largely overlooked in the dis cussion of the next 50 years. The general attitude of those who thought about the subject was somewhat as fol- lows, which we may formulate even though we would find it difficult to point to their exact expression in any par cular work. Rains were observed to fall upon the surface of the earth. The rain water was believed to percolate downward through cavities in the rocks, and to furnish the ground water. In certain wet mines the amount of ground water was highly impressive. Ob- servers therefore concluded that it con- tinued in it's downward passage through ts.e rocks to relatively great depths. During its descending it wandered ex- tensively and took into solution the minerals of our ores and gangue from the rocks with which it came in con- tact. Encountering, perhaps, a large waterway, such as might be furnished by fault line leading to the surface, the solutions mounted upward. Coming from regions of heat and pressure, they passed gradually to those of lower temperatures and diminishing pres sures; the dissolved minerals were pre- cipitated, the veins were filled, and hot springs emerged at the surface. These views were to some extent committed to paper; they were also expounded in the lecture room by Le Conte in the University of California and Newberry in New York. They also found more or less definite expression in the writings of MT. S. F. Emmons and others not engaged in teaching. Whether or not masses of intrusive rock as storehouses of heat assisted in stimulating circulations is not always definitely stated, but probably they were regarded with respect by some, although Dr. Newberry was always rather strenuously opposed to their in fiuence in the production of ores.
 We come now to the meeting of the American Institute of Mining Engi- neers, which was held in Chicago in connection with the Worlds Fair in 1893. Every endeavor had been made to present program of unusual i'm portance. The great paper of the meeting was that from Franz Posepny upon "The Genesis of Ore Deposits. !" The essay was one of exceptional value, and embraced the results of observa- tion and reflection extending over a lifetime. Posepny established two zones. The upper one, between the surface of the earth and the standing ground water, he called the vadose, or shallow zone. In it the operations of the descending rain waters were of an oxidizing nature, and were extremely vigorous. From the level of the ground water to an indefinite depth extended the deep water zone. The movements of the deep waters were slow. The eE- tent to which they penetrated into the earth is not definitely stated, but great