A gravity survey of the Stranraer sedimentary basin

A detailed gravity survey of the Stranraer district of South West Scotland was made by Mr. P. Kennett and the writer. The survey, the subsequent reduction of data and interpretation of the Bouguer anomalies are described. It was found that a negative gravity anomaly of about 17 milligals is associated with the Carboniferous and New Red Sandstone sedimentary basin at Stranraer. The anomalies show that the basin has a maximum depth of not less than three thousand feet and is possibly closer to four thousand five hundred feet deep beneath Luce Bay, The possible nature and density of the concealed sediments filling the basin is discussed and the writer suggests that they are probably mainly composed of New Red Sandstones having a density of about 2.3 gm/cm3.It is suggested further that the basin is bounded by a normal fault or step faults along the eastern side and was formed by contemporaneous down warping and sedimentation.