Microfossils and Precambrian–Cambrian boundary stratigraphy at Maldeota, Lesser Himalaya

Abstract

AbstractAn assemblage of problematical microfossils of Precambrian–Cambrian boundary age is redescribed from the Chert–Phosphorite Member, at the base of the Lower Tal Formation of Maldeota in the Lesser Himalaya of India. This assemblage has previously been ascribed to various ages, from Precambrian to Cretaceous, but is held by us to contain:Maldeotaia bandalica, Protohertzina anabaricagroup, trumpet-shaped elements, acicular elements A & B, ?Conothecasp.,Ovalithecacf.multicostata, allathecid sp. A,Barbitositheca ansata, Hexangulaconulariacf.formosa, Coleoloidesaff.typicalis, Hyolithellusaff.insolitus, H.cf.isiticus, H. vladimirovae, Spirellus shankariandOlivooides multisulcatus. These compare closely with assemblages found above the base of the first,Anabarites trisulcatus–Protohertzina anabaricaZone in China and in the second,Pseudorthotheca costataZone of southern Kazakhstan. The stratigraphic setting of the Krol–Tal succession is reviewed and several similarities are noted between the Precambrian–Cambrian boundary successions of Lesser Himalaya in India and of Yunnan and Sichuan in Southwest China, indicating that correlation between them is possible at several levels.