ROCK VARNISH (Syllabus: GS Paper 1 - Geography)

Context:  Interactions between minerals and microbes present in rocks in arid regions result in a superhero called rock varnish - an orange-yellow to black coating found on exposed rock surfaces in these areas, according to a study carried out in Ladakh. 

Key Points

• This superhero from Nature which shields the rocks from further weathering could help in the design of similar bio-inspired products and raw materials for the paint and pigment industries, manufacturing of water-resistant materials as well as natural UV protectors.
• The varnish surface of rocks in semiarid places of the world presents an ideal environment for microbial development and a large number of researchers have been trying to decode the mysteries behind such varnish formation. 
• Intrigued by rock varnishes found on big boulders in cold, arid Ladakh in NW India.
• Introducing the concept that surface chemistry and hydrophobicity could play a crucial role in facilitating microbial processes related to varnish formation, a perspective not extensively explored before, the study paves new avenues in the field of bioinspired materials, as rock varnish possesses characteristics that make it a unique geomaterial.