Late Proterozoic organic-walled microfossils from the infrakrol of Solan, Himachal Lesser Himalaya: An additional age constraint in the Krol Belt succession

Abstract

The cherty nodules of the Infrakrol Formation, exposed at Anjighat near Solan, Himachal Pradesh, contain a diverse and abundant microbiota of organic-walled microfossils (OWMs). These include cyanobacterial filaments, coccoids, large acritarchs and vase-shaped microfossils (VSMs). These forms identified in the organic-walled microfossils assemblage are: Eomycetopsis robusta, Siphonophycus kestron, Eomicrocoleus crassus, Oscillatoriopsis media, Obruchevella aff. parva, Diplococcus-shaped structures, Huroniospora psilata, Palaeoanacystis vulgaris, Sphaerophycus parvum, Leiospheridia sp., 'Form A' and 'Form B' (large acanthomorphic acritarch) and vase-shaped microfossils. Based on these organic-walled microfossils and considering the recently proposed Precambrian (Vendian) and Early Cambrian ages for the overlying Krol and Tal formations respectively, a Late Proterozoic (Possibly Early Vendian) age is concluded for the Infrakrol Formation.