Drilling fluid (DF) used in the drilling of crystalline continental crust is considered a potent contaminant for subsurface rock samples, though it could provide a glimpse into the nature of deep subsurface life. Microbial communities of DF retrieved from Koyna pilot borehole (3000 m) in the Deccan Traps was explored through 16S rRNA and other diagnostic marker genes. Detection of extremophilic and other deep biosphere relevant microorganisms in DF redefined the role of DF in deep life research.

The Chikyu Shallow Core Program (SCORE) has been started to provide more opportunities for scientific ocean drilling of shallow boreholes (up to 100 m) during a short-term expedition. The proposal flow is a simplified version of that of the International Ocean Discovery Program (IODP). Although there are several limitations for a SCORE project, the opportunity to retrieve 100 m of continuous core samples will be of interest for the scientific ocean drilling community in multiple disciplines.

PalaeoCADIX-Z is an interdisciplinary project that studied three cores drilled in a marine palaeochannel that ran through the ancient city of Cádiz (Spain). These cores reveal a ≥ 50 m thick Holocene sedimentary sequence. Importantly, most of the deposits date from the 1st millennium BCE to the 1st millennium CE. Geoarchaeologists, geomorphologists, archaeologists, sedimentologists, palaeoenvironmentalists, geochemists, and geochronologists collaborated within this project.

The IODP scientific ocean drilling program drilled into the sediments of the Bengal–Nicobar submarine fan system west of Sumatra, Indonesia. Within the cores, a large piece of fossilized wood was discovered, 9 million years in age and buried beneath 800 m of sediment; it is thought to be the largest wood fragment found in scientific ocean drilling boreholes. The wood is believed to be a species of flowering plant and may have originated from the north, east, or even as a result of a tsunami.

Our planet experienced enormous environmental changes in the last 10 million years. Lake Tanganyika is the oldest lake in Africa and its sediments comprise the most continuous terrestrial environmental record for this time period in the tropics. This workshop report identifies key research objectives in rift processes, evolutionary biology, geomicrobiology, paleoclimatology, paleoecology, paleoanthropology, and geochronology that could be addressed by drilling this globally important site.