A new source-to-sink synthesis of the Middle Triassic Helsby Sandstone Formation (Sherwood Sandstone Group) river system of the British Isles
Author(s)
Yan, Xiang
Hampson, Gary J
Whittaker, Alexander C
Type
Journal Article
Abstract
Sediment grain size and mineralogy change in sediment routing systems from source to sink. A better understanding of sediment routing allows improved predictions to be made of the bulk grain-size and mineralogy of sandstone fairways. We present a new appraisal of sediment routing in the Triassic Helsby Sandstone Formation (Sherwood Sandstone Group) and lowermost Mercia Mudstone Group of the British Isles, which constitute a key play for geological sequestration of CO2. These strata were deposited and supplied by a major, north-flowing river system, which is traced from its source region in north France to beyond the Irish Sea. We construct a new, integrated litho- and chronostratigraphic model to correlate key units across the British Isles. We then present sediment isopachs and volumes for this chronostratigraphic interval, and resolve palaeogeographic discrepancies using published sedimentological datasets, supplemented by a new synthesis of bulk sandstone mineralogy. Finally, we present a unified, updated sediment routing map for the Helsby Sandstone Formation. Substantial north-south differences in bulk sandstone mineralogy indicate that that sediment input from tributaries modified the composition of the Helsby Sandstone Formation along the course of the sediment routing system.
Date Issued
2026-07-01
Date Acceptance
2026-03-15
Citation
Journal of the Geological Society, 2026, 183 (4)
ISSN
0016-7649
Publisher
Geological Society of London
Journal / Book Title
Journal of the Geological Society
Volume
183
Issue
4
Copyright Statement
© 2026 The Author(s). Published by The Geological Society of London. Publishing disclaimer: https://www.lyellcollection.org/publishing-hub/publishing-ethics. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/)
License URL
Publication Status
Published
Date Publish Online
2026-07-02