Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986
Remote Sensing applications in the Eastern Bolivia Mineral
Exploration Project (Proyecto Precambrico): Techniques and
prospects
E.O’Connor & J.P.Berrange
British Geological Survey, Nottingham, UK
ABSTRACT: LANDSAT imagery in various modes, and conventional aerial photography, played an indispensible role
in the planning, construction of topographic basemaps, field surveying and identification of exploration
targets for Proyecto Precambrico. The project was sponsored by the British Government's Overseas Development
Administration and carried out the first ever systematic geological mapping and mineral exploration in a
Precambrian shield area of ca 220,000 km 2 largely covered with tropical forest.
No basemaps existed for the northern half of the project area and a series of eight 1:250,000 topographic
basemaps and one at 1:500,000 scale were prepared using enhanced false—colour imagery, panchromatic aerial
photography and limited ground data.
LANDSAT hardcopy prints in black and white and false colour at various scales from 1:100,000 to 1:1,000,000,
and panchromatic aerial photography in stereoscope mode was used routinely for photogeological interpretation
and mapping of the region as a whole.
Interactive computer processing of LANDSAT CCT's of selected areas included colour-compositing, ratioing,
ratio compositing , edge and contrast stretch techniques. The processing was carried out at intervals in
different laboratories e.g. Purdue University (LARS-PDP system); NCRS, Farnborough, (IDP system), Silsoe
(Gems system), Nottingham University (PDP 11/34 base system) and BGS, Keyworth (I 2 S system).
The resulting transparencies and colour-prints provided important additional data for geological mapping and
mineral prospecting purposes. This included the detection of forest covered granitoid plutons with related
fracture systems and the recognition of topographic and/or vegetational anomalies related to important mineral
discoveries in the region. These are the Cerro Manomo carbonatitic complex with P, RE, U & Th mineralisation;
silica caprocks with rich underlying garnieritic Ni deposits formed on ultramafic rocks of the layered Rincon
del Tigre Igneous Complex; and banded Fe and Mn formation (BIMF) in the SE sector of the shield.
