The sedimentology and petrology of the new red sandstone of the Elgin Basin, North East Scotland

Williams, David, Ph.D.

Abstract

The New Red Sandstone Elgin Basin occupied the approximate position of the present day Moray Firth. The basin was dominantly continental in character although periodic marine incursions occurred from the main Norwegian Basin to the east.

To the south of the basin at Elgin, deposition began during the Upper Permian with a series of sheetflood deposits which graded laterally into seif dunes to the north. Deposition during the Triassic is dominated by aeolian barchan dunes although minor point bar, playa and floodplain deposits were' present. A caliche, horizon terminates deposition during the late Triassic. The sediments were derived from the south and south west from an Old Red Sandstone, Moinian and Dalradian source. Fluorite and barytes cementing the dune sandstones were probably introduced prior to the Upper Triassic although. remobilisation occurred in association with the galena- haematite-silica-calcite mineralisation during the Middle or Upper Jurassic. The mineralising fluids were introduced along contemporaneous faults.

In the west of the Elgin basin, a series of distal alluvial fan deposits were laid down during the late Triassic in the Golspie area. They were derived from the Old Red Sandstone and Moinian to the west. As at Elgin, faulting and accompanying mineralisation occurred during the Middle or Upper Jurassic.

Boreholes in the Moray Firth indicate that evaporites and intertidal deposits were laid down in the centre of the basin from the early Permian to the end of the Triassic. The four major environmental zones recognisable in the Permo-Triassic Elgin Basin are (a) Pediment Zone, (b) Sand Sea Zone, (c) Intertidal Zone, and (d) Evaporite Zone.

Palaeowind analyses indicate that the basin was influenced by the north easterly Trade Winds throughout the Permian and Lower Triassic although the presence of south westerly winds during the Upper Triassic may indicate a change in climatic conditions.

Citation

Williams, D. P. The sedimentology and petrology of the new red sandstone of the Elgin Basin, North East Scotland. (Thesis). University of Hull. https://hull-repository.worktribe.com/output/4213737

• Thesis Type: Thesis
• Deposit Date: Feb 19, 2013
• Publicly Available Date: Feb 22, 2023
• Keywords: Geology
• Public URL: https://hull-repository.worktribe.com/output/4213737
• Additional Information: Department of Geology, The University of Hull
• Award Date: Aug 1, 1973