Gondwana sediments get deposited from Upper Carboniferous, so there is no Ordovician diamictite in Peninsular India that can be referred to Gondwana sedimentary rocks.

In the Tethyan part Ordovician non-glacial diamictites occur from Peshawar to Nepal. Existence doubtful in Bhutan

Dear Haider A-Ani

Thank you very much for sending me two nice papers. I got some positive idea about diamictite/tillite in this region. Specially, Middle to Late Ordovician age of the Black Mountain of Bhutan (Bandopadhyay and Gupta, 1990). So, I need more information about this glacial deposits. If possible please send me more those references.

Dear Om N. Bhargava

I am very inspired from you. I also believe Ordovician deposits are possible in this region. I have already got some evidences in Bangladesh but I don’t have available dating facilities for that rocks. You know very well about Late Ordovician glaciogenic diamictite/tillite deposits of North Africa (Guinea, Senigal, Mauritania, Mali, Algeria, Morocco, Tunisia, and Libya) and into the Arabian Peninsula and possibly Turkey (Sheehan, 2001 and reference therein) and position of south pole during Ordovician . That case, Indian subcontinent was very close with Africa. Anyway, I would like to seek more information from you. Thanks.

Haider

I think that Ismail is looking for information regarding the Hirnantian event rather than the Carboniferous and PC glacial episodes. smail there is a lot of useful information in the documents available here:

http://igcp591.org/books.php

Dr Hossain,

Attached is review paper of mine, which

The attachment has failed, please see Bhargava (2008) Geological Society of India Memoir 74, pp. 209-244 and Bhargava (2010) Geological Society of India Memoir 78, pp. 69-99

The other one

Dear Keith Nicholls

Yes, my interest is also on similar Hirnantian event in Indian subcontinent rather than Carboniferous and PC glacial episode. Thanks for your attachment, I'll follow these articles. Thanks.

Dear Om N. Bhargava

Thanks for your attachments. I am really happy to see these articles. Lots of information on Cambrian/Ordovician geology. I am reading these articles. Hope it would be more helpful for getting idea about my interest.

This may also interest you, cause of Ordovician diamictites

Dear OM N. Bhargava

Thank you very much for your support. I failed to open this attachment. Please tag again or send me to my email: [email protected].

A study of a formation, which should contain the Ordovician-Silurian boundary, but as such no tillite found.

SINHA, H N, VANDENBROUCKE T R.A. & VERNIERS, J. (2011). First Ordovician chitinozoans from Indian Gondwana. Review of Palaeobotany and Palynology 167 (1-2), 117-122. doi:10.1016/j.revpalbo.2011.07.006.

We failed to find Ordovician-Silurian boundary fossils, possibly there was a diastem in response to ice age

Of course, Overlying the Cambrian Formation in Spiti after a break there is the diamictite rock referred to as Thango Formation. This is Early-Middle Ordovician in age.

Dear Jacques Verniers

Yes, referred journal is clearly defined Ordovician-Silurian boundary by chitinozoan data, though they do not find/discuss about diamictite/tillite. Thanks.

Dear S. Shah

It is very important information that the diamictite in Thango Formation is Early-Middle Ordovician in age. Thanks.

Dear Om N. Bhargava

I would like to know the lithology of the Wachi La Formation (Late Ordovician-Middle Silurian age), Bhutan. If you have, please help me.

First- Age of Thango is Early to middle Ordovician, but of diamictites, which are restricted to the basal part it is Early Ordovician.

Wachi La is mainly calcareous, with some buildups, kindly consult GSI Special Publication 39 The Bhutan Himalaya:A geological Account (1995)

Dear Om N. Bhargava

Thanks for your reference. In the meantime I read many papers and got lots of information on Ordovician age in Indian subcontinent. But I did not get enough information of Ordovician deposit in Bhutan Himalaya. Hope I'll get more information in future. Regards.

In Bhutan Nake Chu Fm was regarded as Ordovician, our work found that it rests below the Cambrian hence could not be Ordovician, it is Neoproterozoic equvalent of Blaini in the Himalaya and Nantuo in China.