MAGNETIC AND TECTONOSTRATIGRAPHIC CORRELATION AT A TERRANE BOUNDARY -THE TAPPINS GROUP OF THE SOUTHERN UPLANDS

Prominent aeromagnetic anomalies around Ballantrae in southwest Scotla nd have long been associated with extensive outcrops of basic/ultrabas ic igneous rocks in the Midland Valley terrane. However, recent reproc essing of data from a 1978 detailed aeromagnetic survey has demonstrat ed excellent correlation between discrete aeromagnetic features and ce rtain magnetic greywacke formations within the early Caradoc Tappins G roup. This heterogeneous unit forms the oldest and most northwesterly tectonostratigraphic tract in the Southern Uplands terrane and is char acterized by relatively high detrital magnetite (and serpentinite) con tent and elevated values for Cr and Ni. This suggests original close s edimentary Links with an ophiolitic terrane not unlike the presently a djacent Ballantrae Complex (or its extensive along-strike correlatives ), a consideration which has important implications for terrane recons tructions in this region.