Lineaments are manifested as natural formations in different forms of planar geometrical figures; continuous straight lines or broken lines occurring on the extensions of one another or as point formations situated on a single straight line. It needs to be emphasized that continuous extended lineaments as well as broken chains of lineaments, traceable without change in orientation through different landscapes, geomorphological and litho facial units, usually represent different elements of the landscape.

The Cavery Basin in Tamilnadu provides an excellent study area for such an analysis. Many geological features in this basin are linearly arranged, including major uplifts, faults, and fractures.

Mesofracture zones:
The study of mesofracture zones deserves special attention in view of the importance of locating dilatation and fissure zones in the productive horizons for solving petroleum geological problems.

Mesofracture zones are identified in large scale satellite imagery and high altitude aerial photos as high density lineament zones with a width of up to a few kilometres and a length up to several tens of kilometres, consisting of numerous relatively short (1-4 km) and near parallel lineaments. The genetic nature of these zones is determined by their relations to plicate and disjunctive structures.

Mesofracture zones have the following characteristic features: they are organized systems of individual lineaments with consistent orientations; They independently intersect different types of relief, litho facial and stratigraphic associations of rocks, without change in direction; They are essentially independent (discordant) from plicated tectonics, i.e., they intersect, without change in strike, fold structures at different angles to their axes; further, the orientations of individual elements of mesofracture zones are usually not dependent on the direction and morphology of the anticlines and other elements of the folds; They have different widths and predominantly contain fractures with lengths of many kilometres, usually exceeding the dimensions of the folds; the intensity of fractures (fracture density) does not increase within the fold structure; They have complex and diverse relations with known faults, which coincide with mesofracture zones only in isolated cases and in limited areas; faults in local structures of sedimentary rocks, confirmed by drilling, are rarely reflected on satellite imagery; The internal structure of mesofracture zones, even in shield area, is often represented by different combinations of lineament complexes reflecting diverse morphologies(step type, linked on echelon etc); Often, the large mesofracture zones are accompanied by ‘dependent’ satellite fracture systems.

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