The Cretaceous/Tertiary (K/T) boundary controversy has matured to the point where it is important to document the mosaic of environmental and geologic processes that encompassed the earth 66 m.y. ago., especially in the classic continental sections in western North America and in the classic marine sections in Scandinavia. PI's will test the contention that basaltic volcanism was a dominant progenitor of the Mg-smectite clay mineral in the (K/T) boundary clay unit in Scandinavia, and (2) will assess the role of basaltic volcanism in producing Ir anomalies. We have reported a significant new evidence that the K/T boundary clay unit at Stevns Klint (the Fish Clay), which is dominantly composed of an unusual Mg-smectite clay, is formed by alteration of basaltic pyroclastic ash as opposed to being formed from impact derived glass or ejecta. A basaltic pyroclastic origin is supported by our finding of large subhedral labradorite grains in layer III of the Fish Clay. Our initial findings also suggest that basaltic volcanism took place before, during and after the deposition of shocked quartz in the Fish Clay. Mineralogic, clay mineralogic, noble metal and rare earth element chemical analyses of the Mg-smectites compared to similar analyses of Paleocene basaltic tuffs and bentonites of the North Sea region and of the Skane basalts of southern Sweden of uncertain age provide an excellent opportunity for evaluating the role of basaltic volcanism at the K/T boundary in Scandinavia. The geographically confined Skane basalts which heretofore have provided an unrealistically wide range of dates (150 m.y - 80 m.y) will be redated, paying close attention to avoiding xenolithic contamination.
