Airborne geophysical survey of part of Anglesey, North Wales

An airborne magnetic, electromagnetic and radiometric survey was carried out over part of Anglesey, North Wales. In this report of the survey, an outline of the geology, with brief descriptions of survey techniques, data reduction and presentation are given. General descriptions are presented of four areas of distinct magnetic character, with interpretations of the more prominent anomalies such as those associated with the Carmel Head Thrust, with Tertiary dykes and with various hornfels bodies. Possible extensions of known ultrabasic bodies and areas where other such potentially mineralised bodies may be concealed have been shown, in particular near Llandyfrydog (SH 44 85)and near the coast south of Valley (SH 31 76). The electromagnetic survey data are not described in detail because radio transmissions caused strong anomalies unrelated to the geology and masked most of the real anomalies. Those anomalies which remained were due largely to man-made objects. Examination of the radiometric traces showed no indication of uranium mineralisation or any other substantial concentration of radioactive elements.