Columnar Trap Dyke of Potla, District Dewas, Madhya Pradesh, India: a Geological Marvel and Potential Geotourism Destination

Abstract

India is endowed with rich geological heritage through its significant geological structures, geomorphologic features, landscapes of rocks, etc., and attracts the attention of earth scientists, nature lovers and common man too. Most landscape features possess unique values that need to be recognized nationally and internationally, conserved as Geoheritage sites as developed and promoted as Geotourism destinations. The present paper embodies and discusses aesthetic importance and geologic values of Columnar jointed basaltic dyke of Potla, also known as Kawadia Pahad—a geological treasure of Dewas District, Madhya Pradesh. The Potla dyke exposed in the form of seven detached linear ridges, trending ENE–WSW over a distance of 4.5 kms, having an average width of 80 m and exposed couple of meters (36 to 51 m) above the general ground level. The in situ columns in the dyke-ridges that so far been observed show straight, parallel faces without any striations. The length of the horizontal columns ranges between 1 and 3.60 m. The columns which are inclined and penetrated deep inside may have greater lengths. Such exposed columns have a height of 4.10 m which may be extending far downward. As far as diameter of the columns is concerned, it ranges between 30 and 50 cm. Each dyke-ridge consists perfectly separate, very well-developed, finely stacked and interlocked, horizontal to sub-horizontal columnar joints that inclined at various degrees. The columns are polygonal in the dyke-ridges, and majority show tetragon, pentagon, and hexagon shapes in cross section, but occasionally cyclic-hexagons can also be seen. The central part of the dyke, i.e. part of CR-5 and W-4 dyke-ridges, exhibits Dyke-Sill Hybrid Geometry. This monumental dyke-sill interface is not observed anywhere else except Columnar Trap Dyke of Potla, though this interpretation is based on orientation/interrelation of columns in the field. It is suggested that 66.6 ± 0.5 Ma is the crystallization age of the columnar basaltic dyke of Potla. The dyke is rarest of rare, and therefore, numbers of amenities are recommended to fascinate the tourists so that this Geosite should be developed and promoted as a new Geotourism destination of India. The Potla dyke is picturesque and matchless in which the development of the columns is magnificent and the arrangement of the columns is amazing. This world-class dyke fulfils all the requirements of Geoheritage and Geotourism and should get the status of National Geological Monument (NGM). It should also be included in the list of IUGS Geological Heritage Sites.