Themes

Theme 1/ Climate & Ocean Change, Ecosystems: Reading the Past, Informing the Future

“The Earth’s climate system has demonstrably changed on both global and regional scales since the pre-industrial era, with some of these changes attributable to human activities” (IPCC, 2001). We are facing amplified global warming since the 1970’s, a rising sea level, regional climate shifts, and extreme climate events that severely impact the human habitat.

Therefore, IODP/ICDP programs contribute to the understanding of present and past variations in regional and global climate.

• What have we learned from the geological past about natural change?
• How does earth’s climate system respond to elevated levels of atmospheric CO₂?
• How do ice sheets and sea level respond to a warming climate?
• What controls regional patterns of precipitation, such as those associated with monsoons or El Niño?
• How resilient is the ocean to chemical perturbations?
• What are the interplay between volcanic activities and climate variations through time?

Theme 2 / Biosphere Frontiers: Deep Life and Environmental Forcing of Evolution

Little is known about the lower depth limit of life. The factors that control the abundance and activities of microorganisms at depth are still poorly understood. There is only a very limited number of boreholes with a focus on the Deep Biosphere.

• What are the origin, composition, and global significance of deep subseafloor communities?
• What are the limits of life in the subseafloor realm?
• How sensitive are ecosystems and biodiversity to environmental changes?

Theme 3 / Earth Connections: Deep Processes and Their Impact on Earth’s Surface Environment

The ultimate origin of the Earth’s dynamic behaviour is to be looked for in deep-seated processes including mantle convection and melt generation and migration. Scientific drilling offers a unique opportunity to explore the nature of the lower crust and of the shallow mantle in active tectonic settings. The samples collected are essential to validate models derived from the geochemical composition of lavas, experimental petrology and numerical simulations.

• What are the composition, structure, and dynamics of earth’s upper mantle?
• How are seafloor spreading and mantle melting linked to ocean crustal architecture?
• What are the mechanisms, magnitude, and history of chemical exchanges between the oceanic lithosphere and seawater?
• How do subduction zones initiate, recycle volatiles, and generate continental crust?

Theme 4 / Geohazards: Deep Processes and Their Impact on Earth’s Surface Environment

Plate margins are areas where the most life-threatening geological phenomena occur. Ocean-margin geohazards include tsunamis, landslides, powerful volcanic eruptions, and other threats. Scientific drilling has a high potential for risk-mitigation studies, and must be an integral and indispensable part of this effort. For instance, only deep drilling provides access to seismogenic zones for monitoring and to retrieve samples from there.

Earthquakes and tsunamis manifest themselves in seconds to hours, but are the result of stress built up over thousands and millions of years deep within the Earth at distant locations.

• What mechanisms control the occurrence of destructive earthquakes, landslides, and tsunami?
• Active faulting is by far the most common earthquake-generating process. However, little is known on fault processes. It is important to make great strides towards a better characterisation of fault behaviour, and therefore an improved understanding of hazardous zones.
• How do fluids link subseafloor tectonic, thermal, and biogeochemical processes?
• What properties and processes govern the flow and storage of carbon in the subseafloor?

Volcanic eruptions are one of Earth's most dramatic and violent agents of change. Powerful explosive eruptions can drastically alter land and water for tens of kilometers around a volcano.

• Some volcanoes exhibit precursory unrest that if detected, (e.g. by drilling), and analyzed in time allows eruptions to be anticipated.

Impact Structures: Each day extraterrestrial matter collides with Earth. Throughout Earth's history, giant impacts created wide craters and devastations affecting the whole planet. These events may have wiped out major portions of the fauna and flora on the Earth. Still, large impacts are the fastest geological events creating new ground for evolution. Currently ca. 196 impact craters are known on Earth; about one third of those structures are not exposed on the surface, and can only be studied by geophysics or drilling. Drill cores yield information on the subsurface structures, and provide ground-truth for geophysical studies.

Theme 5 / Sustainable Georesources

The problem is one of maintaining the natural resource base for economic growth by increasing exploration and production efficiency (energy and minerals) whilst also preserving other valuable resources (potable water and ecosystems).

• Deep Life: Bacteria, viruses and archaea dwell at depths to several thousand meters below ground and in temperatures of more than 120° C. Their metabolism contributes to the generation of carbohydrates and mineral resources. These rich ecosystems are studied by scientific drilling.
• Volcanoes: Inside the Earth there is heat so intense that it melts rock and drives tectonic processes and planetary differentiation. Geothermal energy can be tapped from the Earth's natural heat at volcanoes or mantle plumes. Holes drilled into a subsurface geothermal system, or in volcanic areas, can drive turbines and generate electrical power.
• Element Cycles: Drilling can help identify and develop increasingly sparse natural resources, e.g. water.
• Plate Margins: Most of the erosion and deposition of sediments is culminating along the plate margins. This may form deposits of georesources, accessible only by drilling.