Eight sites were drilled along the EG63 transect on the Southeast Greenland margin during Legs 152 and 163 (Fig. 1) (Larsen and Saunders, 1998). At Hole 990A we penetrated 212 m of sediment and 131 m of basaltic basement at a water depth of 540 m (Duncan, Larsen, Allan, et al., 1996). The goal for this site was to drill deeper than in the nearby Site 915 to obtain a complete volcanostratigraphic section at the inner part of the EG63 transect. Fourteen subaerially emplaced basaltic flow units were identified, consisting of a mixture of dominantly plagioclase-olivine phyric basalt and aphyric basalt (Fig. 2). The units are classified as aa (four upper units), transitional (four middle units) and pahoehoe (five lower units). A downhole decrease in unit thickness was observed.

The core recovery in the massive interior of the lavas was often complete. A number of cores actually had a recovery of >100%, being related to inaccuracies in the driller's depth, spaces in the curated core, and possible recovery of core drilled during the previous drilling. In contrast, recovery in the top and base of the flow units is lower, frequently 30%-60%.

Units 2 and 9 and Subunit 3A were chosen for detailed studies of petrophysical properties near the flow boundaries. Unit 2 and Subunit 3A are thick aa basalts with well-defined weathered flow tops; Unit 9 is a very vesicular pahoehoe basalt (Fig. 2; Table 1). The massive interior of the units was almost completely recovered. Based on the general high recovery of the massive part of the units, we interpret the missing section in Cores 8R and 12R (Fig. 2) to belong to the strongly altered flow top. Eighteen minicore samples were selected from these three units for further studies.