Skip to Main Content

Furongian (Cambrian) agnostoids of Scandinavia and their implications for intercontinental correlation

Per Ahlberg and Fredrik Terfelt
Furongian (Cambrian) agnostoids of Scandinavia and their implications for intercontinental correlation
Geological Magazine (November 2012) 149 (6): 1001-1012


Out of the 14 agnostoid species/subspecies so far recorded from the Furongian of Scandinavia, seven are excellent biostratigraphical indices and important for correlation between Baltica and other palaeocontinents. Glyptagnostus reticulatus, Aspidagnostus lunulosus and Agnostus (Homagnostus) obesus first appear at the base of the G. reticulatus Zone, allowing a precise correlation of the base of the Paibian Stage into Scandinavia. Tomagnostella orientalis and Pseudagnostus cyclopyge appear near the base of the Parabolina brevispina Zone, suggesting a correlation with the uppermost Paibian through the lowermost Jiangshanian stages. Lotagnostus americanus and Pseudagnostus rugosus have an intercontinental distribution and their first appearance in Scandinavia allows for a correlation with one of the most favourable levels for defining the base of Cambrian provisional Stage 10. In the Furongian of Scandinavia, agnostoids are conspicuously assembled in three different intervals: the lower Glyptagnostus reticulatus Zone, the lower Pseudagnostus cyclopyge Zone and the Lotagnostus americanus through lower Trilobagnostus holmi zones. The agnostoid-barren and largely unfossiliferous succession separating the lower and middle agnostoid-bearing intervals can be explained by means of subsequent dissolution of the calcareous fauna and/or a hostile environment. The middle agnostoid-bearing interval is succeeded by an anomalous succession dominated by the orthide brachiopod Orusia lenticularis, reflecting a regressive event coupled with increasing levels of oxygen at the sediment/water interface. This shallowing evidently resulted in unfavourable conditions for agnostoids.

ISSN: 0016-7568
EISSN: 1469-5081
Coden: GEMGA4
Serial Title: Geological Magazine
Serial Volume: 149
Serial Issue: 6
Title: Furongian (Cambrian) agnostoids of Scandinavia and their implications for intercontinental correlation
Affiliation: Lund University, Department of Earth and Ecosystem Sciences, Lund, Sweden
Pages: 1001-1012
Published: 201211
Text Language: English
Publisher: Cambridge University Press, London, United Kingdom
References: 75
Accession Number: 2013-028391
Categories: StratigraphyInvertebrate paleontology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sketch map
N55°15'00" - N60°15'00", E12°00'00" - E18°00'00"
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, Cambridge University Press. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201318
Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal