Sedimentology of the early Neoproterozoic Morar Group in northern Scotland: implications for basin models and tectonic setting

H. C. Bonsor, R. A. Strachan, A. R. Prave, M. Krabbendam

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

The metasedimentary rocks of the Morar Group in northern Scotland form part of the early Neoproterozoic Moine Supergroup. The upper part of the group is c. 2-3 km thick and contains two large kilometrescale facies successions: a coarsening-upwards marine-to-fluvial regression overlain by a fining-upwards fluvial-to-marine transgression. Fluvial facies make up less than a third of the total thickness; shallow-marine lithofacies make up the remainder. Combining these new findings with previously published data indicates that the Morar Group represents, overall, a transgressive stratigraphic succession c. 6-9 km thick, in which there is both an upward and eastward predominance of shallow-marine deposits, and a concomitant loss of fluvial facies. Smaller-scale (hundreds of metres thick) transgressive-regressive cycles are superimposed on this transgressive trend. Collectively, the characteristics of the succession are consistent with deposition in a foreland basin located adjacent to the Grenville orogen, and possibly linked to the peri-Rodinian ocean. Subsidence and progressive deepening of the Morar basin may have, at least in part, been driven by loading of thrust sheets emplaced during the Grenville orogeny, and aided by sediment loading. However, the relative contributions of thrust loading versus plate boundary effects and/or eustatic sea-level rise on basin evolution remain speculative.

Original languageEnglish
Pages (from-to)53-65
Number of pages13
JournalJournal of the Geological Society
Volume169
Issue number1
DOIs
Publication statusPublished - Jan 2012

Fingerprint

Dive into the research topics of 'Sedimentology of the early Neoproterozoic Morar Group in northern Scotland: implications for basin models and tectonic setting'. Together they form a unique fingerprint.

Cite this