CHARACTERIZATION OF DIFFERENT LINEAMENTS TYPES FROM TM-5 LANDSAT IMAGES AND THEIR 
APPLICATION TO CONTROL OF GOLD-QUARTZ VEINS IN THE PORTO NACIONAL (TO) REGION, BRAZIL 
Fabio S. e Silva da Cunha, Evandro Gottardo & Adelir J. Strieder 
Department of Mining Engineering - Federal University of Rio Grande do Sul (UFRGS) 
Av. Osvaldo Aranha, 99 - sala 502b - 90.035-190 - Porto Alegre - RS - Brazil 
E-mail: adelir@lapes.ufrgs.br 
Commission VII, Working Group 4 
KEY WORDS: Geology, Mapping, Landsat, Lineament Analysis, Ore Control 
ABSTRACT 
The lineament analysis technique was developed since the usage of aerial photographs in geology. From the advent 
of satellite image use, this technique received a new dimension for interpretation, since the satellite images favour 
the overlook of a given area. However, the method used to extract and to interpret the lineaments patterns remains 
the same; the current usage is based on the extraction of lineaments as much as possible, in order to build up a 
pleasant arrangement. No regards are made to distinguish different types of lineaments. This paper is based on the 
experience got in lineament study for gold-quartz veins control in the Porto Nacional (TO) region, Central Brazil. It 
aims to emphasize the importance of distinguishing at least two lineament types at the extraction. This method 
enables the discrimination between ductile and brittle structures and the understanding of the geometric nature of 
these structures. The observations have shown that it is possible to distinguish between two types of lineaments: a) 
type 1 and b) type 2. The type 1 lineaments are related to penetrative structures (regional foliations, transcurrent 
shear zones and granite intrusions) and display rectilinear as well as curvilinear patterns; they develop paired positive 
and negative geomorphic features and are associated with tonal banding, because of lithological changes. The type 2 
lineaments are related to brittle disjunctive structures (joints and faults) and are often rectilinear to slightly curvilinear; 
they represent negative geomorphic features, characterized by drainage patterns, and are also important features to 
the control of most of the gold-quartz veins. 
1. INTRODUCTION Corrego Cachimbo Granite-gneiss Suite (CCGgS), 
Natividade Metassedimentary Suite (NMS), Matança 
The Porto Nacional (TO) region has been target for gold Metagranitic Suite (MMgS), lpueiras Granitic Suite 
research and artisanal minings since the last century. (IGS), Monte do Carmo Formation (MCF), Parnaíba 
The area has a complex structural framework Basin Sedimentary Sequence (PBSS) and Cenozoic 
characterized by a system of sinistral transcurrent Deposits (figure 1). 
shear zone trending N30°E, that are regarded to the 
Transbrasiliano Lineaments (Schobbenhaus et al., The PNC is composed by two principal petrographic 
1975). The shear zones were also place for J[ithotypes: a) a mafic rock and b) a quartz-feldspathic 
hydrothermal fluids percolation and show thick quartz rock. The mafic rocks are ortogneisses of dioritic to 
veins; the veins are mainly in the subsidiary dilatant gabroic composition, with porfiroid texture. The quartz- 
faults, distributed in various directions, and are the feldspathic rocks are composed by granodioritic to 
main source for primary gold. tonalitic ortogneisses. 
Recently, the temporal and spatial relationship between The CCGgS rocks are very deformed and 
the ore and the tectonic structures of the region were metamorphosed, presenting a narrow gneissic banding. 
discussed by Mesquita ef al. (1992) and by Strieder et These rocks can be characterized by fine grained biotite 
al. (1994). The observations presented in these papers granodiorites to monzogranites in the low strain 
demonstrated the importance of make a detailled portions. The higher strain zones has extensive 
characterization of the geometric properties of such formation of secondary muscovite. This lithologic unit is 
structures, to evaluate the structural control of the ore crosscut by a large quantity of auriferous veins, with 
occurrences and to select new prospective targets. The varied characteristics and sizes. 
first step of this characterization was the visual analysis 
and interpretation of lineaments from satellite images, The lithologic types that constitute the NMS are mainly 
since the synoptic vision of the region showed large metaconglomerates, ^ metasandstones,  quartzites, 
importance in the obtained results (Cunha, 1996). conglomeratic ^ quartzites, ^ micaceous  quartzites, 
aluminous schists, tremolite schists and graphitic 
2. GEOLOGICAL SETTING OF THE PORTO phyllites. This sequence is locally crosscut by quartz 
NACIONAL (TO) REGION veins, with milimetric to centimetric thicknesses, and 
intruded by metabasic dikes. 
2.1. Lithological Framework 
The lithotypes that compose the MMgS are 
The lithological framework of Porto Nacional (TO) metagranitoids (sienogranites to monzogranites) which 
region is constituted by the following lithodemic and show magmatic and high temperature tectonic 
lithostratigraphic units: Porto Nacional Complex (PNC), foliations. The primary texture is a coarse 
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International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996