THE PHILIPPINE 



Journal of Science 



A. Chemical and Geological Sciences 

 and the Industries 



Vol. VIII APRIL, 1913 No. 2 



ORE DEPOSITS OF THE PHILIPPINE ISLANDS 



By F. T. Eddingfield 



(From the Division of Mines, Bureau of Science, Manila, P. I.) 



Three plates and 4 text figures 



The discussion of the genesis of the ore deposits of the Phil- 

 ippines is handicapped by the lack of sufficient data in regard 

 to primary ore. Mining is in its infancy, and most of the 

 operations of mining and development have been carried on 

 wholly in the zone of oxidation. This is particularly true of 

 those deposits which represent the most important gold ores; 

 that is, those made up of manganese, calcite, and quartz, and 

 of manganese and quartz alone. However, conditions of a 

 somewhat exceptional nature are encountered which present 

 opportunities for discussion. These are, mainly, the compara- 

 tive youth of the rock formations, the evidence of volcanic 

 activity throughout the Islands, the abundance of mineral 

 springs, the unusually large number of veins within a limited 

 area, and the association of manganese, calcite, and quartz in 

 many of the mineral deposits. 



GEOLOGY 



The rocks of the Philippine Islands for the most part are 

 of Tertiary or post-Tertiary age. Very few have been found 



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