Sikkim is located over young fold mountains called Himalayas which is formed relatively recent as compared to other parts of the mountains in the world. As per the geological time scale the earth is 4.5 billion years old whereas the Himalayas have been formed only 35 million years ago.
Hence, it is known as young fold mountain (K.S Valdaya’ Text Book of Himalayan Geology). Due the tectonic upliftment in the process of Himalaya’s formation a series of folding, faulting lineaments, fractures, jointing patterns and intrusions in the rocks are common geological features encountered across
the Sikkim topography.
The geological process takes place in such a way that sometimes it leaves us mesmerized looking at its wonderful structural formations. From sand dunes to snow dunes, mountains to plains, we see geological formations from nano-sized to gigantic.
This rock block is located along Chungthang-Lachung road section about 2 kms before Lachung, District Mangan. The mineral composition of the rock is calcareous, quartz, silica, mica aggregated in gneissic rock with quartz veins intrusion which can be seen on a rock as a unique structural formation. Due to the competency difference in aggregated rock mass, it has resulted in a formation resembling a meandering river.
Description Of Rock Block
Host Rock Gneissic Length 3.5 meters Breadth 1.5 meters
Intrusion Quartz Length 3.5 meters Breadth 7.5 centimeters
The structural formation resembles more like a fold and it can be useful for Researches and Scholars to understand the limbs, axis and axial plain of the fold. The structural formation on the rock shows that the different minerals aggregated in a single rock block has their own unique esistance to temperature and weathering. As shown in the rock block the fold like structure is composed of quartz which shows that the quartz is highly competent as compared to the other aggregates. While on the way to Lachung those interested can see and observe this specimen of our glorious nature and geology at work.
Writeup Mines & Geology Department
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