Geological interpretations of the gravity field of the Western Midland valley of Scotland

Alomari, Maath Ismail (1980) Geological interpretations of the gravity field of the Western Midland valley of Scotland. PhD thesis, University of Glasgow.

Abstract

A review of the deeper geology of the Midland Valley of Scotland and results from previous geophysical studies are discussed and presented. The principal new gravity coveraae was in the area of the Lesmahapow Inlier. A reaional Bouguer anomaly map of the western Midland valley and its environs was compiled, using existing data and carrying out surveys locally to fill gaps. The heterogenous existing data was reduced to give uniform reference to NGRN 73 and the IGF 67 formula. The combined results were analysed by orogressive stripping of the gravity components related to particular formations. Firstly thickness map of the supra-Hurlet sediments was prepared and its gravity effect calculated. Next, the thicknesses of the Clyde Plateau Lavas was calculated from the magnetic anomaly mao of Great Britain (Sheet 11) with due allowance for the effects of intrusions, (particularlyd-Bathaate). The pseudo-gravity effect of this Lava model was then calculated. Reduced Bouguer anomaly maps are obtained by subtracting the Bouguer anomaly components arisinc from the supra-Hurlet sediments and the Lavas (plus associated intrusions) from the total gravity field values. Residuals were then analysed on the assumotion that their major sources were most probably (i) the structure of the major crustal layering and (ii) the variation of (residual) thickness of the Lower Old Red Sandstone. A range of interoretations, as well as a 'most probable' model, was obtained. Estimates of the 'crustal gravity component' were made (1) by fitting a best surface to the reduced gravity values and (2) by combining the Upper crustal gravity component as calculated for LISPS model, with McLean and Qureshi's estimate of the regional component. The gravity anomaly residuals attributable to the Lower Old Red Sandstone component are discussed and geological interpretations made.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: Q Science > QE Geology
• Colleges/Schools: College of Science and Engineering
• Supervisor's Name: McLean, Dr. A.C. and Powell, Dr. D.W.
• Date of Award: 1980
• Depositing User: Alastair Arthur
• Unique ID: glathesis:1980-76758
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 09 Dec 2019 16:36
• Last Modified: 09 Dec 2019 16:42
• Thesis DOI: 10.5525/gla.thesis.76758
• URI: https://theses.gla.ac.uk/id/eprint/76758