I'll be of the radar for the next couple of weeks or so. First to Delhi for some work and then off to Mukteshwar, a small temple town in the Kumaon region of the Himalayas for a few days of hiking and recreation.
Mukteshwar falls in what is known as the Lesser Himalayas. As the name suggest it reflects the physiography of the region as compared to the Greater Himalayas. Overall the Lesser Himalayas as not as rugged and high as the Greater Himalayas. There are geological differences as well.
I've put below a rough sketch of the major litho-tectonic provinces of the Himalayan orogen. These represent the roughly WNW-ESE trending deformed blocks of the Indian plate as the Indian shelf broke up along major faults during the India-Asia collision.
From Delhi I'll be traveling on the Quaternary alluvium until I cross the Himalayan frontal thrust which brings into contact the Quaternary alluvium with the Neogene Siwalik mountains - remnants of the Cenozoic foreland basin that formed in front of the rising Himalayas.
I will then cross the Main Boundary Thrust, which places the Lesser Himalayas over the Siwaliks. The Lesser Himalayas are made up of Proterozoic to Paleozoic rocks (geological division - the Lesser Himalayan sequence) and represent the basement and metamorphosed cover of the Indian shelf. Beyond that in thrust contact along the Main Central Thrust are the Greater Himalayas which are also made up of the Proterozoic basement and Paleozoic metamorphosed cover of the Indian shelf (geological division -Greater Himalayan crystalline complex).
The Greater Himalayas are generally of higher metamorphic grade and may represent the exhumation of a deeper crustal level.
Beyond that.. tectonically juxtaposed with the Greater Himalayas along the South Tibetan Detachment are the Tethyan Himalayas which are composed of mostly unmetamorphosed Paleozoic to Eocene sedimentary cover deposited on the Indian shelf. Beyond that is the zone of collision known as the Indus-Tsangpo suture and beyond that .... the Asian plate.
I've been able to draw only the Himalayan Frontal Thrust and the Main Boundary Thrust with some confidence. I am not well versed enough to pick out the other boundaries between the provinces from a satellite image. But I think I've got the general placement of the provinces correct.
As I mentioned, Mukteshwar falls in the physio-graphic province of the Lesser Himalayas.... but geologically..?
I'll write about it in more detail with some maps and cross sections when I return. There is somewhat of a surprise regarding the geology and structure around Mukteshwar.
The night train from Delhi will put me in the Siwalik foothills by dawn. Its an early morning drive from there up to Mukteshwar which is at an altitude of around 7200 feet.
I hope to catch the sunrise as I drive up the Cenozoic alluvial fans that make up the Siwaliks and cross over into the Proterozoic metasediments of the Lesser Himalayas...