GEOLOGY - CONTAMINATED LAND REPORT

Geology - contaminated land report

Geology - contaminated land report

Introduction

This paper considers the impacts of the development on geological resources and soils and effects resulting from the presence of potentially contaminated land. The baseline geological resource and existing features of note are described. Mitigation measures to reduce negative impacts are set out and residual impacts assessed. Contaminant materials encountered during construction may represent a risk of pollution to subsurface soil and impact upon the health and safety of construction personnel and the general public. Areas of potentially contaminated land are identified based on historical data.

Impacts on Geological Resources

Baseline

Glacial or raised marine deposits with areas of made ground underlie the route. The underlying bedrock comprises sedimentary rocks consisting of mudstone, siltstone, sandstone and occasional thin limestones and coal seams, all of Carboniferous age.

Superficial Deposits

Superficial geological deposits of the area, as described by BGS, indicate that the route is principally underlain by glacial till (boulder clay). Irregular bands or lenses of sand and gravel may occur within the till. The top metre or so of the till is commonly weathered, siltier and somewhat softer than the remainder.

Raised marine deposits are found within the northern area of the route. They are predominantly sand and gravel with subordinate silt and clay layers/bands, resting on glacial till (boulder clay) or rockhead. The underlying superficial deposits are probably of marine origin, consisting largely of silt, sand and gravel with subordinate mud.

Bedrock

The BGS's Geological Summary Site Report has identified bedrock underlying the route as belonging to the lower, middle and upper part of the Gullane formation of the Carboniferous age. The upper and lower part of Gullane formation consists of grey mudstones and siltstones with interbedded sandstones; with no known coals or limestones. The middle part of the Gullane formation consists of grey mudstone and siltstone with interbedded sandstones. A thin limestone and two coal seams are known to be locally present in this part of the sequence.

Mining

A BGS search of their mine plan catalogues and data has revealed no record of any quarrying or former mining of minerals along the proposed route or the depot area, although the presence of unrecorded mine works was not entirely discounted. Many of the sandstones have been quarried in the past for building stone (for example at Craigleith Quarry (see Section 7.4.2)). Additionally, at least one coal seam is known to have been worked on the foreshore, although ...