The sites 504 and 505 of Deep Sea Drilling Project Leg 69 were selected for the purpose of investigating geothermal phenomena in basaltic basement and overlying sediments at two locations in the same segment of an oceanic spreading center-the Costa Rica Rift. Two additional experiments were conducted in Hole 504B to measure the bulk properties of the ocean crust: the large-scale resistivity experiment and the oblique seismic experiment.

From 1983 until 1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions. At the time it was the most extended data compilation on ferromanganese deposits world wide. Initially published in a proprietary format incompatible with present day standards it was jointly decided by AWI and NOAA to transcribe this legacy data into PANGAEA. This transfer is augmented by a careful checking of the original sources when available and the encoding of ancillary information (sample description, method of analysis...) not present in the NOAA-MMS database.