THALLOPHYTIC ALGAE FROM THE KROL FORMATION (EDIACARAN PERIOD), LESSER HIMALAYA, INDIA

摘要

Thallophyte fossils have been discovered from the Krol 'C' Member of the Krol Formation (Ediacaran Period) in the Garhwal Synform of the Lesser Himalaya, India. The fossils described are recovered from the petrographic thin sections of the chert lithounits. Comparable thallophytic algal fossils (Red alga) were previously recorded from the Doushantuo Formation of China and a late Neoproterozoic age was assigned to the fossil bearing strata. We herewith describe the taxonomic details along with the possible biotope in which these fossils occur. The exceptionally well preserved fossils show a body plan where even cellular organization clearly depicts multicellularity. The present record owes its significance to exceptional preservation of evolved algae (eukaryote) which is preserved at cellular level in the silicified lithology (bedded black chert) with fine morphological details at the higher level of strata (Krol 'C' Member). Previous microfossil records are known from the Infrakrol and Krol 'A' Member of the Krol Formation which mainly show either the existence of fossils with cyanobacterial (prokaryote) affinity and giant acanthomorphic acritarchs or a few ill-preserved thallophytic algal remains identified as Wengania globosa. The paper discusses the biostratigraphic significance of the newly discovered thallophytic fossils in the light of Neoproterozoic evolutionary history.