Tertiary basalts of western Davis Strait: bedrock core samples and geophysical data

Abstract

Short bedrock cores of basalt were recovered at two localities on the Baffin Island shelf, 33 and 89 km southeast of Cape Dyer. The volcanic rocks underlying these sites have a surface extent of some 8000 km2 as outlined by seismic reflection and magnetic anomaly profiles. Similar rocks are inferred to occur at two smaller offshore areas south of the main area. The offshore occurrences are both more continuous and much larger than the onshore basalt areas of eastern Baffin Island.The core samples appear to have been cut from single flows consisting of fine-grained microporphyritic basalts with olivine as the principal phenocryst phase. Although having distinct differences from one another in terms of texture and degree of alteration, the samples from the three drill stations bear similarities to the Baffin Island basalts that suggest a close petrogenetic relationship may exist between the onshore and offshore basalts. However, in contrast to the subaqueously erupted volcanic breccias of onshore Baffin Island and West Greenland the offshore samples contain little evidence of glass, suggesting the possibility that the latter may have been erupted in a subaerial environment.