The Moffat Shale group of the Southern Uplands of Scotland : structure, stratigraphy and palaeontology

Eales, Martin Hugh (1978) The Moffat Shale group of the Southern Uplands of Scotland : structure, stratigraphy and palaeontology. PhD thesis, University of Glasgow.

Abstract

The Moffat Shale Group consists of a condensed sequence of pelagic and hemi-pelagic sediments which crop out as elongated inliers in the Northern and Central Belts of the Southern Uplands of Scotland. This thesis deals with the structure, stratigraphy, sedimentology and palaeontology of the inliers in the Central Belt. Biostratigraphical and lithological controls have enabled the stratigraphy of the inliers to be worked out with greater precision than elsewhere in the Southern Uplands. Strike faulting within the greywacke is rarely recognized mainly due to the absence of stratigraphical markers. Within the Moffat Shale strike faults, which are probably rotated thrusts, are common and beds of the same age, but differing in lithology and thickness, are brought into close proximity. This faulting was evidently on a wide scale involving significant tectonic transport. At least two phases of strike faulting are evident associated with the major folding. Such relationships are believed to exist throughout the Southern Uplands and in the Longford-Down Inlier of Ireland. Wrench faulting is ubiquitous throughout the Southern Uplands and is the last significant deforraational phase recognized in the Moffat Shale. The structural analysis for the Moffat Shale is consistent with those described by others who have worked in various parts of the Southern Uplands, except that the role of strike faulting is more emphasized here. This may be because the strike faults are more easily recognizable in the Moffat Shale but it may be that a major decollement occurred near, or within, the Moffat Shale lithology. The Southern Uplands is believed to represent an accretionary prism in which younger thrust slices have been successively accreted from the south-east by under-thrusting. It is suggested also that deformation spread from north-west to south-east and was coeval with the fomation of the accretionary prism. The tern 'Moffatian Orogeny' is proposed for this regional event which occurred from about Middle Ordovician to late Silurian times. At almost every active continental margin where there is sufficient sediment, an accretionary prism is forming which is deformed according to the imbricate thrust model. It is proposed that the Southern Uplands was one such imbricated accretionary prism which formed in the Lower Palaeozoic on the south-eastern margin of the American Plate. In the Appendix several graptolite taxa are discussed. Ten new species and nine new subspecies are proposed from the Ordovician of the Moffat Shale.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: Q Science > QE Geology
• Colleges/Schools: College of Science and Engineering > School of Geographical and Earth Sciences
• Supervisor's Name: Ingham, Dr. J.K.
• Date of Award: 1978
• Depositing User: Enlighten Team
• Unique ID: glathesis:1978-83345
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 06 Jan 2023 09:38
• Last Modified: 10 Jan 2023 09:05
• Thesis DOI: 10.5525/gla.thesis.83345
• URI: https://theses.gla.ac.uk/id/eprint/83345

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