Two closely spaced sites (SEG01 and SEG02) were drilled into volcanic basement on the outer part of Transect EG66. These sites are located ~55 km northeast of Site 988 and on strike with magnetic Chron C24r. Site SEG02 is located immediately landward of Site SEG01 and so was intended to sample marginally older crust. The sedimentary cover was only recovered at Site SEG02 and is composed of 6 m of highly compact diamicton. Despite the inherent difficulties with drilling in this material, the recovery by diamond coring approached 100%. The single igneous flow unit recovered at Site SEG01 is a massive, vesicular, plagioclase-clinopyroxene-olivine phyric basalt. The unit has normal magnetic polarity and yielded a preliminary 40Ar-39Ar age of 50.0 ± 0.4 Ma (C. Tegner, unpubl. data). These latter results show that eruption most likely took place during Chron C22n (50.8–49.7 Ma), as previously shown for Site 988 (49.6 ± 0.2 Ma) (Tegner and Duncan, 1999). This agreement with the findings from drilling Site 988 are important, as they show that (1) young crust is more widespread than previously thought and (2) the averaged seafloor magnetic signature does not correspond well with the age of crust sampled at the surface. Both of these conclusions have important implications for models of volcanic rifted margin formation. Igneous basement was also sampled at Site SEG02, where highly fractured, massive, and sparsely plagioclase phyric basalt was recovered. These igneous units did not yield precise 40Ar-39Ar ages because of excess argon, but the data suggest an age of ~52 Ma (C. Tegner, unpubl. data), which, together with its reversed magnetic polarity, suggests eruption during Chron C23r.
Both analyzed igneous units are relatively evolved with Mg numbers between 0.36 and 0.47 and TiO2 contents of 2.3–3.6 wt%, with the Site SEG02 unit being the more evolved. These Fe-Ti basalts are similar in composition to those from Site 988, the plateau basalts of East Greenland, as well as Paleogene lavas of western Iceland (Hardarson et al., 1997).