The Llandovery graptolite zonation of the Danangou section in Nanzheng, Shaanxi Province, central China, and comparisons with those of other regions

Abstract

The Llandovery (lower Silurian) Liangshan Danangou section of Nanzheng, southern Shaanxi Province, China, contains a complete Aeronian succession and abundant graptolites. One hundred and twenty‐five species of graptolite have been found in this section. Using high‐resolution methods, the Rhuddanian, Aeronian, and Telychian strata of this section have been divided into 3, 4, and 1 graptolite zones, respectively. In particular, there are 47 species of graptolite in the newly established Spirograptus andrewsi Zone (Aeronian) which has 2 subzones; a lower Monograptus enshiensis Subzone and upper Hubeigraptus sp. nov. Subzone. This zone is considered to be a substitute for the Stimulograptus halli Zone, which is widely used but has drawbacks. The paper has made detailed comparisons of the Danangou section graptolite zonation with the Hubei section and with typical zonations in Britain and the Czech Republic. As a result, the Danangou section is considered as a candidate for the stratotype of the Aeronian Stage because of the well‐defined base and top, and the abundant graptolite species.