A unique, far-travelled graptolite-bearing erratic pebble from the Lowestoft Till (Quaternary: Anglian Stage) of North Lopham, Norfolk

Yonan, Yasmin; Zalasiewicz, Jan ORCID: https://orcid.org/0000-0002-3220-4855; Holt-Wilson, Tim; Harvey, Thomas H.P.; Kozłowska, Anna; Porębska, Elżbieta; Danelian, Taniel; Molyneux, Stewart; Williams, Mark; Hoare, Peter G.; Wong Hearing, Thomas W.; Rose, James. 2025 A unique, far-travelled graptolite-bearing erratic pebble from the Lowestoft Till (Quaternary: Anglian Stage) of North Lopham, Norfolk. Proceedings of the Yorkshire Geological Society, 65 (3-4). 10.1144/pygs2023-005

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Official URL: https://doi.org/10.1144/pygs2023-005

Abstract/Summary

An erratic chert pebble discovered on an exposure of the Lowestoft Till (Anglian Stage, Pleistocene) of North Lopham, Norfolk, UK, contains graptolites preserved three-dimensionally in silica in a mode not known in the UK. The graptolites are Monograptus parapriodon , Monograptus priodon , Monoclimacis linnarssoni and an undetermined retiolitid that indicate an Oktavites spiralis Biozone (mid-late Telychian, Late Llandovery, Silurian) age. The graptolites are associated with organic-walled microfossils, some containing internal bodies. The combination of lithology, preservation and low thermal maturity seem to exclude a British origin. The closest comparison is with Silurian chert pebbles in Miocene and Pleistocene gravels in central Germany, thought to be derived from bedrock in the Frankenwald region of Thuringia. A conjectured natural transport vector for this pebble involves drainage along the proto-Rhine system flowing into early/mid Pleistocene North Sea deltaic/marine deposits, with subsequent glacial transport to Norfolk. The possibility of an anthropogenic vector is also considered, but dismissed.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1144/pygs2023-005
ISSN:	0044-0604
Date made live:	28 Apr 2025 13:32 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/539342

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1144/pygs2023-005

ISSN:

0044-0604

Date made live:

28 Apr 2025 13:32 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/539342