Hill of Barra

Also within

Aberdeenshire County

Condition (NatureScot)

Geology & landscape

Landscape processes: Volcanic / Igneous

Description

HILL OF BARRA The Hill of Barra is located about 1 km south of Oldmeldrum. The rocks seen on the hill typify the silica-poor ultramafic rock unit found in a number of important ’Younger Basic’ intruded rock masses that occur uniquely in the north-east Grampian Highlands. The ultramafic unit is believed to represent the early formed cumulates (crystals accumulated at the base of a magma body as it cools and crystalises). The ultramafic unit at Hill of Barra is part of the ‘Younger Basic’ Insch intrusion, and was originally composed of the olivine-rich rock periodotite. The olivine in this peridotite has been highly altered by circulating low-temperature water to serpentine minerals (serpentinised). However, there is still some evidence of rudimentary layering, dipping steeply eastwards, and indicating considerable tectonic disturbance after the intrusion formed. Exposures of these ultramafic rocks are generally very poor but the western slopes of Hill of Barra provide relatively good outcrops.