Petrochemistry and engineering properties of the Helmsdale granite intrusions

Rahmdel, Hossein Salmanpour (1987) Petrochemistry and engineering properties of the Helmsdale granite intrusions. MSc(R) thesis, University of Glasgow.

Abstract

The study of the petrochemistry of the Helmsdale granite intrusions, NE Scotland, reveals that the Helmsdale granite consists of two granitic intrusions; an outer, early, coarser-grained porphyritic pink granite (CGP) and the inner, finer-grained type (FG). Major and trace elements show dissimilarities between the FG and the CGP types, with the former having higher iron, MgO and TiO2, and lower silica contents. Plagioclase and biotite removal appear to be the minerals changing the magma composition towards the later differentiated CGP type. Both granites were subjected to weathering and hydrothermal alteration, although the latter is commonly confined to the zones of intense high K alteration within the FG type (inner intrusion). Ratios such as Na2O/K2O, Al2O3/(SiO2+Al2O3), (Na2O+K2O+CaO+MgO)/Al2O3, Fe2O3/FeO and microfracture index (FI) have been found to be particularly useful as indices of physical and chemical weathering of the granites. Various British standard tests are employed to assess the suitability of the Helmsdale granite aggregates for engineering purposes including roadstone and concrete making. The CGP samples generally have lower strength and slightly better AAV, PSV values than the FG samples type. Apart from badly weathered materials (such as in Eldrable Burn) the Helmsdale granites appear to have the same strength as the Peterhead granite and are slightly below the rest of the granites of Scotland. The AAV values of 3-6% obtained show an acceptable level for aggregate to be used for most highway and trunk road running surfaces whereas the PSV results, on the other hand, suggest that aggregate from the Helmsdale granites can be used for site C with satisfactory performances. Aggregates from the Helmsdale granites are also suitable for most concrete mixtures and satisfactory performances will be achieved except for the purposes of heavy duty concrete floors.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Keywords: Geology, mineralogy.
• Colleges/Schools: College of Science and Engineering
• Supervisor's Name: Gribble, Dr. C.D.
• Date of Award: 1987
• Depositing User: Enlighten Team
• Unique ID: glathesis:1987-73402
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 14 Jun 2019 08:56
• Last Modified: 14 Jun 2021 15:08
• URI: https://theses.gla.ac.uk/id/eprint/73402