Details

Autor(en) / Beteiligte

• Willman, Sebastian
• Slater, Ben J.

Titel

Late Ediacaran organic microfossils from Finland

Ist Teil von

• Geological magazine, 2021-12, Vol.158 (12), p.2231-2244

Ort / Verlag

Cambridge, UK: Cambridge University Press

Erscheinungsjahr

2021

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Here we present a detailed accounting of organic microfossils from late Ediacaran sediments of Finland, from the island of Hailuoto (northwest Finnish coast), and the Saarijärvi meteorite impact structure (~170 km northeast of Hailuoto, mainland Finland). Fossils were recovered from fine-grained thermally immature mudstones and siltstones and are preserved in exquisite detail. The majority of recovered forms are sourced from filamentous prokaryotic and protistan-grade organisms forming interwoven microbial mats. Flattened Nostoc-ball-like masses of bundled Siphonophycus filaments are abundant, alongside Rugosoopsis and Palaeolyngbya of probable cyanobacterial origin. Acritarchs include Chuaria, Leiosphaeridia, Symplassosphaeridium and Synsphaeridium. Significantly, rare spine-shaped sclerites of bilaterian origin were recovered, providing new evidence for a nascent bilaterian fauna in the terminal Ediacaran. These findings offer a direct body-fossil insight into Ediacaran mat-forming microbial communities, and demonstrate that alongside trace fossils, detection of a bilaterian fauna prior to the Cambrian might also be sought among the emerging record of small carbonaceous fossils (SCFs).