Survey Findings
As the hydrothermal alteration zones exist widely in the Oruro-Uyuni region and
also mineral showings exist, it is expected to host epithermal ore deposits at depth.
Considering the mineralization in the Altiplano and the Eastern Bolivian Andes, it
was interpreted that the mineralization in the Western Bolivian Andes is similar to the
Bolivian-type deposit and shows an epithermal type mineralization in the upper part,
while it changes to a polymetallic mineralization in the lower part.
It is reported that the mineralized ages of Chilean porphyry type deposits have a
tendency to become younger from west to east and the porphyry type deposits were
Sixteen Districts were studied in three years.
After the surveys lots of matters about the mineralizations in the Oruro-Uyui region
still remained unknown, nevertheless the following things became clea

1) The satellite image analysis was proved to be useful for selection of alteration
zones, as alteration zones selected by satellite image analysis in this survey
well coincided with the results of the ground truth.

2) The area is underlain by volcanic rocks of early Miocene to Pleistocene, ther
ages,however,showed irregular distributions.
3) Alteration minerals in the volcanic rocks showed a zonation of crystobalite
zone, quartz zone, quartz-sericite zone from the outer part to the center part.
Quartz-sericite zone in the volcanic rocks of Late Miocene or younger, is
generally absent or small if exists, while quartz-sericite zone in the volcanic
rocks of the Middle Miocene or older is widespread.
( 1 )
4) The vein materials showed a variation of clay, clay-silica, silica and quartz
from the outer part to the center part. Manganese oxide is shown inside of
clay in some place. In either case, quartz zone is acompanied by ore minerals
such as gold, silver, copper, lead and zinc.
5) Results of the chemical analysis of samples from the La Deseada vein exposed
from the top to the bottom, values of (gold), (copper), lead, arsenic and
antimony are higher in the upper part of the mineralization, and those of gold,
silver, copper, lead, zinc and antimony increase in the lower part of
mineralization. Combination of these factors and vein character is a good
indicator to consider the portion of a mineralized zone in the same area as
Mendoza District.
6) Homogenization temperatures and salinities of fluid inclusions showed
difference of ore solutions by each vein. Veins showing low temperatures
like the La Deseada vein indicate the possibility of ore deposits underneath.
7) It is not cleared whether the quartz(calcedny)-barite vein changes to Boliviantype? Polymetallic vein, as drilling survey was carried out only in the
Chullcani. The reasen why no sulfide vein was confirmed in the ore
showings in the older volcanic rocks, some part of mineralization in the
Western Andes and Altiplano is considered to be different from the Bolivian type mineralization in the east.
8) Positive showing suggesting the existence of the porphyry type deposit could
not be confirmed .

Copyright © 2014-2023 Pickpol Global Ltd. All Rights Reserved / https://pickpol.com / [email protected]

Scroll to Top