Site U1565

Abstract

Contents 1 Background and objectives 3 Operations 5 Lithostratigraphy 9 Biostratigraphy 12 Paleomagnetism 17 Geochemistry 21 Physical properties 24 References

Site U1566

“…The liner correction of 66/58 = 1.138 should be applied to the WRMSL GRA bulk densities (see Physical properties in the Expedition 396 methods chapter [Planke et al, 2023a]). The value of the liner correction was confirmed for the granitic cores recovered at Site U1565 (see Physical properties in the Site U1565 chapter [Planke et al, 2023b]).…”

“…Site U1566 is a companion site to Site U1565. Both sites are located on the western flank of the Kolga High (see Figure F1 in the Site U1565 chapter [Planke et al, 2023b]) about 1 km apart at a water depth just above 2000 m. The Kolga High is one of several areas along the rifted margin characterized by a thin sediment cover above the top basalt surface and a rapidly westward shoaling of the Base Cretaceous Unconformity (BCU) (Zastrozhnov et al, 2020) (for a summary, see Background and objectives in the Site U1565 chapter [Planke et al, 2023b]).…”

“…The primary objective of Site U1566 was to sample the lowermost part of the SDR on the Kolga High (see Figure F3 in the Site U1565 chapter [Planke et al, 2023b]). If possible, we would also try to drill through the entire basalt sequence, but this was not a key target because the primary target of the nearby Site U1565 was to recover the subbasalt units.…”

“…Although Site U1566 was placed only 1 km away from Site U1565, the seismic data are inconclusive about the dip of the basal surface of the lava pile and hence the depth to this interface. Although high-resolution seismic data (see Figure F3 in the Site U1565 chapter [Planke et al, 2023b]) may indicate that this base basalt is as shallow as 200 meters below seafloor (mbsf ) (depending on the choice of seismic velocity), 3-D exploration seismic data suggest that the basal surface may be as deep as 400 mbsf and out of reach of the planned 200 m hole.…”