NEW INSIGHT INTO OCEAN DRILLING CORES FROM HIGH RESOLUTION IMAGES

Scientific ocean drilling is the window into past oceans. Approximately 454,166 km of core has been recovered since 1968. Freshly recovered core is photographed during shipboard analyses, capturing the conditions of the material in its pristine state. Over time, cores degrade and are sampled, limiting the volume and quality of material available for physical analyses. Decades on, we seek to gain new insight into old cores using shipboard photographs to create new, digital records.

Although the core photographs are an important resource, in their original format their utility is limited. For example, most ODP and all DSDP cores were photographed in a core box using a single lighting source. This makes it hard to view continuous variability in a core, especially as the original lighting causes problematic shadows. To circumvent these issues, the photographs must be processed so the lighting is uniform, then individual sections images are isolated and combined to create a continuous image. This process is carried out using the Code for Ocean Drilling Data (CODD) package for Igor Pro 9 developed by Wilkens et al. (2017). The resulting continuous core images, or virtual cores, were created for 8 Sites (ODP Leg 121 Site 752, Leg 181 Site 1120, Leg 181 Site 1125, Leg 182 Site 1127, Leg 182 Site 1130, and Leg 182 Site 1134. DSDP Leg 28 Site 266 and Leg 90 Site 590). In addition to the creation of a virtual core record, shipboard biostratigraphy data was applied to generate an age model for each of the 8 Sites.

The creation of a virtual core provides the opportunity to revisit older cores with a higher resolution and captures the core as it was before degradation over time and sampling. It has the potential to source new records, such as simulated color reflectance, at much higher resolution than originally collected, or even as a new dataset in the case of older expeditions where color reflectance data was not collected. The virtual core is a complementary source of research for cores, particularly when the core is not accessible to the researcher.