AR 1978-79.pdf - Birbal Sahni Institute of Palaeobotany

15
5.2. Pol1enanalysis
5.2.1. Pollen zonation schemefor Western Himalaya, Rajasthan
and Nilgiris-A paper on the local and regional pollen
zones and their delimitation in Indian pollen diagrams deal·
ing with the present day criteria for pollen zonation together
with the history of thought and the application of the criteria
and Indian pollen diagrams was prepared and submitted
for publication.
A. Ll1dakh-A surface sample from neal' the alpine
Tsokar Lake, 5,000 m a. s. I.) revealed dominance of nOI1­
arboreal over the arboreal pollen of which Pinus, Cedrus,
Picea and Ahzes are derived froOi temperate regions through.
upthermic winds. Juniper pollen was poorly represented
against its higher values in the pollen profile from this lake.
The Tsokar Lake pollen diagram from a profile of about
23.85 m and dated by radiocarbon to the last glaciation is
largely dominated by herbaceous pollen belonging to Compositae,
Chenopodiaceae and Urticaceae. \Vith the exception
of Juniper pollen, pollen of temperate genera such as
Abies, Picea, Cedrus and Pinus are indeed derived. The biogenic
evidence, rise in Juniper pollen frequencies and the
radiocarbon date of 30,600 ± 140 years B. P. suggests an
interstadial (equivalent of Dcnekamp in Europe) at 21-22 m
depth. Rise in temperature or lack of snow-fall during
211000 - 15,000 years B. P. is apparent from the increase in
Juniper pollen and during the period an environment 01
disturbed soil was prevalent as indicated by a rise in Urticaceae
pollen.
B. Himachal Pradesh
The pollen analysis of the 6 samples from subtropical
Un chi-Bassi profile has shown the dominance of non-arbo-