Sedimentology and provenance of the Lower Old Red Sandstone Grampian outliers: implications for Caledonian orogenic basin development and the northward extension of the Midland Valley Basin

Zoe McKellar*, A. J. Hartley, D. I. M. Macdonald, Andrew Morton, Dirk Frei

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Reconstructing regional geological histories is challenging where basins have limited and/or fragmentary preservation. Several isolated outlier basins of Lower Old Red Sandstone (LORS) occur on the Scottish Grampian terrane; however, their sedimentology and relationship to other similar-aged LORS deposits has been poorly constrained, as has their significance in the wider Caledonian orogenic framework. Here we present a combination of new sedimentological and multidisciplinary provenance analyses for the LORS outliers at Aberdeen, Cabrach, New Aberdour, Rhynie and Tomintoul. Three facies associations are identified, the deposits of locally derived conglomeratic alluvial fans, which pass upward into fluvial channel and floodplain facies associations. Provenance data from conglomerate clast populations, sandstone petrography, heavy mineral assemblages, and U-Pb detrital zircon geochronology indicate derivation from the surrounding Dalradian Supergroup, with local influence from contemporaneous volcanic or plutonic lithologies. These data suggest a similar provenance to that of the northern Midland Valley Basin LORS, and a direct relationship between the LORS north and south of the Highland Boundary Fault. This indicates that the preserved outliers represent fragments of wider, unpreserved LORS cover that accumulated between the late phases of the Caledonian Orogeny and onset of post-orogenic collapse in the Mid-Devonian.

Original languageEnglish
Article numberjgs2020-141
Number of pages18
JournalJournal of the Geological Society
Issue number2
Early online date22 Jan 2021
Publication statusPublished - Mar 2021

Bibliographical note

Acknowledgements: We thank Steven Andrews for providing additional field photographs for Tomintoul. We also thank Rufus Brunt, Linda Kirstein, Nigel Mountney and an anonymous reviewer for their insightful comments, which helped to improve the manuscript.

Funding: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Author contributions: ZM: conceptualization (lead), data curation (lead), formal analysis (lead), investigation (lead), methodology (lead), project administration (lead), visualization (lead), writing – original draft (lead), writing – review & editing (lead); AJH: conceptualization (supporting), methodology (supporting), project administration (supporting), resources (lead), supervision (lead), visualization (supporting), writing – review & editing (supporting); DIMM: supervision (supporting), writing – review & editing (supporting); AM: formal analysis (supporting), methodology (supporting), writing – review & editing (supporting); DF: formal analysis (supporting).

Data Availability Statement

Data availability: All data generated or analysed during this study are included in this published article (and its supplementary information files).


  • U-PB AGE


Dive into the research topics of 'Sedimentology and provenance of the Lower Old Red Sandstone Grampian outliers: implications for Caledonian orogenic basin development and the northward extension of the Midland Valley Basin'. Together they form a unique fingerprint.

Cite this