96 The Philippine Journal of Science mm 



VEIN GOLD DEPOSITS 

 SUYOC 



The Suyoc mineral district, located in the Mountain Province, 

 about 65 kilometers north of Baguio, contains a number of gold- 

 bearing veins, varying from 1 to 4 meters in width. The vein- 

 filling is mostly quartz, but occasionally stringers of calcite are 

 found along the walls. Manganese is very subordinate, and was 

 found in noticeable amounts in only one vein. Several veins 

 carry tellurides, but in the majority of cases the gold was found 

 free or associated with zinc, lead, copper, and pyrites. 



The veins are found in conglomerate, diorite, andesite, andesite 

 breccia, and along the contacts between igneous and sedimentary 

 formations. The Assuring seems to have occurred after the for- 

 mation of the sedimentaries, and was probably influenced by the 

 intrusion of the Bagan granite, which lies west of the district. 



BAGUIO DISTRICT 



The Baguio district is located near Baguio, Benguet, and 

 occupies an area of about 100 square kilometers. This district 

 was profoundly shattered, and probably contains as many mineral 

 veins as any district of its size in the world. Some of the veins 

 are shown in Plate I. It can be divided according to the class 

 of veins into four distinct sections: 



1. The Antamok Valley: The characteristic vein matter is 



quartz, manganese, and, in a large number of cases, cal- 

 cite. The gold occurs in the metallic state, but is also 

 associated with iron pyrites, insignificant amounts of 

 copper, and, in some cases, with galena and silver. 



2. Itogon Biver: Calcite predominates in fissure veins in the 



diorite. A few quartz stringers were found carrying 

 copper. Gold values are low. 



3. Gold Creek: Calcite is almost entirely absent. Numerous 



quartz veins are found carrying free gold values and 

 varying amounts of iron pyrites. Quartz veins carrying 

 tellurides were found in the northern part of this group. 

 Toward the south, copper values increase, and veins con- 

 taining appreciable amounts of copper and lead are notice- 

 able. Two veins carrying cinnabar were also discovered. 



4. Bued River: A large percentage of copper is found in the 



majority of the veins, usually accompanied by high gold 

 values. Calcite is absent. 



