ANALYSES OF ROCK SURFACE COLOUR CHANGES DUE TO WEATHERING

Description parameters of rock masses and minerals include their colours as well. Colours appear in daylight for surfaced rock masses are changing slightly due to weathering layers which have been covering its surface gradually. Healthy human eyes can manage to differentiate visible light spectrum to identify colours of substances including rock masses. Then visible blackish colours of magnetite minerals, reddish colours of Terra- Rosa soils, greenish colours of weathered copper ore, pure white of salt minerals and many others are differentiable by naked eyes. Different colours and homogeneity of colour distribution for natural rocks are also main grading parameters of natural rock surfaces. In addition, colour can also be parameter to identify weathered rock surfaces. Outcrop rock mass surfaces or rock discontinuity surfaces which could be influenced by weathering factors, have their altered surface colours in general that, those colours can be different from the original rock colours. In this study, colour changes were determined in digital manner by obtaining rock surfaces’ Red, Green, Blue digital colour (RGB) values. Digital colour differences have been then analyzed more specifically to evaluate rock weathering and colour changes.