Bhubaneswar: The Geological Survey of India (GSI) has declared “Natural Arch” near Hemgir in Odisha’s Sundargarh district as Geo Heritage Site. This is the second Geo Heritage Site in the state.
The Natural Arch was found in dense Chhengapahar reserve forest near Brahmani village during exploration for coal in Kendudihi Block, Ib River Coalfield of the district. Surrounded by cliffs and steep sloped hills from almost all sides, the arch is difficult to approach and has carnivorous wildlife such as bear.
The arch has a length of 30 metre at the base and height of 12 metre. Its alcove has maximum height and width of 7 metre and 15 metre respectively. Geometrically, the arch is oval shaped.
According to geological experts, the formation of natural arch might be ignited by the fault system and associated joints while the porosity of the poorly sorted, immature, arkosic and loose sandstone accelerates the process through subaerial weathering. Therefore, it may be mentioned as structurally triggered – weather eroded natural arch, they added.
It may be mentioned that the GSI has earlier declared Pillo Lava at Nomira in Keonjhar district as a Geo Heritage Site. Pillow Lava is an exposure of well-preserved pillow structures. Individual pillows are roughly ellipsoidal and closely packed with a maximum thickness of 2m x 0.6m.
The basic lava is fine to medium grained, green to bluish green coloured with abundant vesicles filled with quartz. The lavas and the associated pyroclastics and tuffs are underlain by quartzite and overlain by shale, chart‐ shale and banded hematite jasper.
