Systematic paleontology, acritarch biostratigraphy, and δ13C chemostratigraphy of the early Ediacaran Krol A Formation, Lesser Himalaya, northern India

Abstract

AbstractAcritarch biostratigraphic and δ13C chemostratigraphic data from the Krol A Formation in the Solan area (Lesser Himalaya, northern India) are integrated to aid inter-basinal correlation of early–middle Ediacaran strata. We identified a prominent negative δ13C excursion (likely equivalent to EN2 in the lower Doushantuo Formation in the Yangtze Gorges area of South China), over a dozen species of acanthomorphs (including two new species—Cavaspina tiwariaeXiao n. sp.,Dictyotidium grazhdankiniiXiao n. sp.), and numerous other microfossils from an interval in the Krol A Formation. Most microfossil taxa from the Krol A and the underlying Infra-Krol formations are also present in the Doushantuo Formation. Infra-Krol acanthomorphs support a correlation with the earliest Doushantuo biozone: theAppendisphaera grandis-Weissiella grandistella-Tianzhushania spinosaAssemblage Zone. Krol A microfossils indicate a correlation with the second or (more likely, when δ13C data are considered) the third biozone in the lower Doushantuo Formation (i.e., theTanarium tuberosum-Schizofusa zangwenlongiiorTanarium conoideum-Cavaspina basiconicaAssemblage Zone). The association of acanthomorphs with EN2 in the Krol Formation fills a critical gap in South China where chert nodules, and thus acanthomorphs, are rare in the EN2 interval. Like many other Ediacaran acanthomorphs assemblages, Krol A and Doushantuo acanthomorphs are distributed in low paleolatitudes, and they may represent a distinct paleobiogeographic province in east Gondwana. The Indian data affirm the stratigraphic significance of acanthomorphs and δ13C, clarify key issues of lower Ediacaran bio- and chemostratigraphic correlation, and strengthen the basis for the study of Ediacaran eukaryote evolution and paleobiogeography.UUID:http://zoobank.org/5289fdb2-0e49-4b3b-880f-f5b21acab371.