Hope he didn;t change his emails and working place .. but i guess you still able to contact him. He did a lot of researches of sedimentology work in India and river sedimentology analysis.
Are you referring to northern border of the Indian plate, or the present day political border of India? The latter is not easy to answer very simply. As you know, India is a large country and its geology shows considerable change from Assam to Kashmir. There are juxtaposed fold-thrust belts, suture zones, HP-UHP rocks, island arcs, Asiatic (formerly Gondwanic) blocks and of course the Siwaliks.
You might like to contact Wadia Institute of Himalayan Gelogy, Dehradun, India, and Dept of Earth Sciences, Indian Institute of Technology, Roorkee, India. Their e-mails should e available on the internet.
I am working in North eastern Himalaya-Siang Valley but the research is on Foreland basin not the Himalaya.. although I will try my best to help you. Please let me know