Llandovery sporomorphs and graptolites from the Manbo Formation, the Mojiang County, Yunnan, China

Abstract

Llandovery sporomorphs and graptolites have been recovered from the Manbo Formation, Mojiang area, western Yunnan, China, which belonged to the Indo-China Palaeoplate in the Palaeozoic. The graptolite fauna, including 8 genera and 12 species, is considered Mid Telychian, Llandovery in geological age, confirming the existence of Llandovery rocks in this region. The Silurian stratigraphical sequence of this area is reconsidered as in the ascending order: Manbo Formation (Llandovery-early Wenlock), Shuiqing Formation (late Wenlock-Ludlow) and unnamed formation (Pridoli?). The sporomorph assemblage from the Manbo Formation includes seven species in five genera. The dominant members of this assemblage are Tetrahedraletes medinensis and Laevolancis chibrikovae. Based on the low diversity and low abundance, the geological age of this assemblage is considered to be approximately the Telychian, Llandovery. The parent plants of sporomorphs probably inhabited the landmass near Mojiang area, these sporomorphproducing plants probably included bryophyte-like land plants and primitive vascular land plants. The sporomorph evidence shows that the South China and Indo-China palaeoplates may have been in close proximity (maybe with some continental bridges linking them) to each other at least in the Llandovery. They were also closely related with Gondwanaland in the Llandovery.

Llandovery (lower Silurian) graptolites from the Sepon Mine, Truong Son Terrane, central Laos and their palaeogeographical significance

“…This view was reiterated by Zhang et al (2014, p. 28). However, as Wang and Zhang (2010) acknowledged, Silurian cryptospore species are cosmopolitanevery one of the seven species recorded by Wang and Zhang (2010) has a very wide distribution, from high southern palaeolatitudes (sites in North Africa and Argentina) through to localities on Laurentia and South China widely accepted to have been at tropical palaeolatitudes. On the basis that it is thought that spores could not be distributed across wide oceans, Steemans and Pereira (2002) concluded that the uniformity of Upper Ordovician and Llandovery sporomorph assemblages could be best explained using palaeogeographical reconstructions with only narrow oceans separating the continents.…”

“…Telychian (upper Llandovery) graptolites from Mojiang County were initially illustrated and discussed briefly by Wang and Zhang (2010), then described in detail (with some different identifications from those in Wang and Zhang, 2010) by Zhang et al (2013), with a few species re-illustrated by Zhang et al (2014, fig. 3.12).…”

The contribution of women to Welsh geological research and education up to 1920

“…(Geikie, 1908) The foregoing citations by eminent geologists of the day show without doubt the esteem in which these female geologists were held in for their pioneering work in Wales. Indeed some of their research, such as Wood (1901-1918) and Ida Slater (1907) is still widely cited (Leme et al, 2008;Storch and Loydell, 1996;Wang and Zhang, 2010) and is the authoritative work today.…”

Recent advances in Chinese palaeontology

“…Palaeobiogeography is a topic of general interest to palaeontologists and a thread through several publications of this special issue: Zhou et al (2010b) present a nice analysis on the evolutionary trends and palaeobiogeography of an Ordovician trilobite genus. Wang & Zhang (2010a) provide new information concerning the Silurian biostratigraphy and palaeogeography based on new data from sporomorph and graptolite fossils. Sha's (2010) work on non-marine Cretaceous trigonioidid bivalves provides new information concerning the palaeogeography in the Cretaceous of Asia.…”

“…Wang & Zhang (2010a) provide new information concerning the Silurian biostratigraphy and palaeogeography based on new data from sporomorph and graptolite fossils. Sha's (2010) work on non-marine Cretaceous trigonioidid bivalves provides new information concerning the palaeogeography in the Cretaceous of Asia.…”