ABSTRACT The Tuya-Kawdy region of northern British Columbia is well established as a place where glaciation and volcanism overlapped in space. However, no modern work has integrated observations from the region’s volcanic and glacial deposits with geochronologic constraints to summarize how they might overlap in time. Here, we provide a general overview of such characteristics and 23 new 40 Ar/ 39 Ar eruption ages of glaciovolcanic deposits ranging from 4.3 Ma to 63 ka to constrain the timing, location, and minimum thicknesses and distributions of coincident ice. Subaerial lava fields interspersed with glaciovolcanism record periods of ice-sheet absence in presumably warmer climate conditions. These generally coincide with interglacial marine isotope stages. Many of the volcanoes have a secondary record of posteruption glacial modification, cirques, erratics, and mega-lineations, which document later climate changes up to the present. We used edifice-based terrain analysis to reconstruct changes to local minimum Cordilleran ice-sheet thicknesses, extents, and flow directions at specific locations and times during the late Pliocene and the Pleistocene.

Abstract The Late Bronze Age (LBA) eruption of Santorini volcano deposited ash over most of the eastern Mediterranean, distributed thick deposits of pyroclastic material over the local landscape, and instantly buried the Minoan-aged living surface of these islands. Ground-penetrating radar (GPR) studies of the LBA volcanic deposits on Thera have allowed us to establish the thickness of individual pyroclastic units, to trace units laterally, and to establish facies variations in areas where the deposits are unexposed. GPR data are presented for two sites: Site A is a survey over LBA volcanic deposits exposed in the Phira quarry, immediately south of the town of Phira, and Site B is a 550 m survey of the LBA deposits underlying the Akrotiri peninsula immediately north and south of the Akrotiri archaeological excavation. These traverses show that GPR can define structures as deep as 18-20 m (velocity 0.1 m ns -1 ) and can accurately map the thicknesses of the LBA volcanic deposits from the caldera wall to Thera's southern coast. Furthermore, our best datasets suggest that the Phase 1 fall deposits can be differentiated from the Phase 2-4 deposits, and that GPR can clearly image the interface between the volcanic deposits and the underlying LBA living surface. Future GPR surveys could be used to delineate palaeotopographic lows and valleys associated with LBA streams or drainages or, used in combination with geological mapping, could refine the position and nature of LBA shorelines.