Meall Dail-chealach

Also within

Perth and Kinross County

Condition (NatureScot)

Geology & landscape

Rock Type: Schist

Description

Meall Dail-chealach Meall Dail-chealach is located 3.5km northwest of Trinafour, and includes two small areas containing exposures of metamorphic rocks belonging to the Dalradian Supergroup, formed over 600 million years ago. Earth movements, around 400 million years ago, compressed and buried these rocks so that they were metamorphosed and deformed. Several different episodes of deformation occurred, folding the rocks into complex structural forms. One of the latest episodes produced a major fold called the Trinafour Monoform, which folded the rock layers into a step-like shape. The hinge, or edge of the step in this fold, can be seen in rock out crops on the north east side of Meall Dail-chealach Here the (D4) Trinafour Monoform refolds the (D3) Errochty synform, affecting lithologies of the Grampian and Argyll Groups, including the Beoil Schist which marks the “boundary slide”. At Meall Dail-chealach, banded psammitic flags of the Grampian Group occur on the steep limb of the Trinafour Monoform, whilst the lower hinge of the monoform is seen east of the Dubh Lochan. The Trinafour Monoform is the most important (D4) monoformal structure in this area, and it attains its maximum development at Meall Dail-chealach. The evidence the site provides makes possible the tectonic reconstruction of the area and allows the demonstration of its four major structural episodes.