To deliver the Earth and Life Sciences discoveries needed to meet the challenges society faces as stewards of our changing planet




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Discovering Earth's Hidden Frontiers through Scientific Ocean Drilling


Initial Science Plan 2013 - 2023


Draft 2: 19/08/2010


Vision:

To deliver the Earth and Life Sciences discoveries needed to meet the challenges society faces as stewards of our changing planet.


Mission:

To employ ocean drilling technology required to obtain unique insight to understand and predict Earth’s dynamic system and its impacts

To inspire & train the next generation of geoscientists

To communicate our scientific discoveries to the public and to decision makers


The Science Plan Writing Committee


Mike Bickle (University of Cambridge, Chair);

Christina Ravelo (UCSC) ;

Heiko Palike (NOC, University of Southampton);

Rob DeConto (University of Massachusetts, Amherst);

Fumio Inagaki (JAMSTEC);

Katrina Edwards (University of Southern California);

Naoh Ohkouchi (JAMSTEC);

Andrew Fisher (University of College of Southern California);

Damon Teagle (NOC, University of Southampton);

Demian Saffer (Penn State);

Gilbert Camoin (CNRS);

Peter Barrett (University of Wellington);

Shuichi Kodaira (JAMSTEC);

Richard Arculus (Australian National University );

Richard Norris (Scripps Institution of Oceanography)


Liasons


Hans Christian Larsen, (IODP-MI)

Maureen Raymo, (SASEC)

Hiroshi Kawamura, (IODP-MI)

Yoshi Tatsumi, (BoG)

Susan Humphris, (BoG)


Contents

Preface

Executive Summary

1 Introduction

1.1: Scientific Overview

1.2: Implementation

1.3: Management

2: Climate and Ocean Change: Reading the Past, Informing the Future


Preface


This document presents the second draft of the New Science Plan for the Integrated Ocean Drilling Program2*. The IODP2 is an international program to explore beneath the oceans by drilling the ocean floor, recovering core and carrying out real-time observations and experiments in boreholes.

The Plan presents the scientific frontiers for which exploration beneath the oceans will enable transformative advances. The topics include those of fundamental interest as well as urgent questions related to management of the environment, resources and geological hazards. Exploration beneath the oceans is essential for understanding processes in the solid Earth, oceans, atmosphere, climate and the biosphere and their important inter-relationships. The science structure of IODP2 will be managed in a responsive mode with the flexibility to respond to an evolving science agenda, seize new opportunities and respond rapidly to emerging urgent issues. The Plan summarises the important scientific, educational, and societal benefits to be gained by deploying this transformational new infrastructure.

This Science Plan was prepared by the Science Writing Plan Committee, nominated by the IODP community, short listed by the Science Advisory Structure Executive Committee and confirmed by the International Working Group+. Others who assisted with the preparation of parts of this document by contributing text, figures, or comments include Paul Pearson, Sasha Turchyn, Mike Cheadle and Ros Rickaby. This document draws heavily from many earlier workshops and meeting reports, but we wish to specifically acknowledge the INVEST Workshop held September 22-25, 2009 in Bremen co-chaired by Wolfgang Bach and Christina Ravelo.


The document is currently incomplete. Figures will be properly planned and redrawn and at present are included as examples. The implementation, management, education and outreach sections have yet to be drawn up. The layout, numbering and titles and subtitles are all preliminary.


Executive Summary

Geological processes continually modify the Earth we live on and, in doing so, control the evolution of landscape, oceans, atmosphere and biosphere. These processes are both of fundamental interest and of immediate societal concern as anthropogenic activities impact the Earth’s surface environment, deplete natural resources and become increasingly sensitive to natural hazards.

Drilling in the deep oceans is essential to our understanding of the processes that shape the Earth. This is because only the deep oceans preserve the sedimentary sequences that record continuous temporal records of Earth processes (the ‘fourth’ dimension), and because the oceans cover the active manifestations of the Earth’s driving tectonics which reveal its inner workings and cause major geological hazards.

Past ocean drilling has been central to many of the most important advances in the Earth sciences over the last 40 years including verifying plate tectonics and establishing the science of palaeoclimate. Most recently ocean drilling has revealed the magnitude of past climatic changes in the polar regions, documented changes the instability of icesheets, extended high resolution climate records back to ~ 2 million years and drilled down to fossil magma chambers in the lower part of intact oceanic crust. The current program includes the ambitious multi-expedition NanTroSEIZE project to reveal the mechanisms of the most damaging subduction zone earthquakes, expeditions investigating the little-known deeply buried microbial communities and drilling to understand mantle convective motions and melting.

The new IODP2 program will employ a spectrum of drilling technologies and downhole instrumentation to enable transformative advances in understanding of climate science, in the operation of biological communities in the oceans and in the subseafloor, and in the operation of the solid Earth and its interactions with the surface environment.

Explanation of the nature and causes of climate change on all timescales is of fundamental scientific significance with urgent societal implications. Only oceanic sediments contain the palaeoclimate records with the spatial distribution and time range against which we can test the climate models used to predict future climate change. These records have already revealed failures of the modelling including prediction of meridional temperature gradients during warmer climates and the rapidity of icesheet collapse and sealevel rise.

The development of new and more sophisticated proxies is enabling the determination of the physical, chemical and biological states of past oceans, palaeo-ocean circulation, the behaviour of ice sheets and past continental vegetation patterns. This, combined with targeted and transect drilling to recover high resolution (sub-millenial) records and improved correlation between records, is revolutionising our ability to reconstruct past climatic states and their regional variability. Immediate applications will be to the determination of past climate sensitivity to atmospheric CO2, ice sheet instability and sealevel change, the response of the hydrological cycle to changing climate, and the impacts of anthropogenic ocean acidification.

Advances in genetics, molecular biology, geochemistry and palaeobiology coupled with recovery of high resolution time records by drilling and the ability to characterise the physical and chemical states of the ocean will allow determination of how past ocean ecosystems responded to environmental change. Especially important is how these ecosystems responded to climatic warming analogous to predicted future warming. The time and spatial resolution of the records will provide tests for modern theories of evolution. The ocean biosphere may be an important moderator of the Earth’s surface environment and the drilling records will be critical in resolving the leads and lags between changes in the biosphere and climate and hence causality in patterns of change.

Drilling has discovered a vast “deep biosphere” buried in sediments and the crust. The limits of life in these environments remains to be determined, as does their role in global geochemical cycles. New genetic sequencing techniques will enable classification of the microbial populations and investigation of their ecology. Study of these isolated communities will provide new perspectives on evolutionary processes and the origin of life as well as the limits on life and the potential for life on other planets. Drilling is the only way to access the deep biosphere.

The continually recycled oceanic crust most directly reflects mantle processes. Drilling strategies and technologies have now advanced to the stage where the whole oceanic crust and uppermost mantle can be sampled. The consequent understanding of the interacting magmatic and hydrothermal processes that form the crust will constrain the composition and compositional heterogeneity of the mantle. This information will be critical to resolving the dilemma posed by recent exquisite seismic tomographic images of the Earth showing subduction zones penetrating the lower mantle whereas the isotopic compositions of mantle magmas require long-term segregation of their source regions.

Better estimates of hydrothermal fluxes through the oceanic crust will resolve current order-of-magnitude uncertainties in geochemical fluxes between the solid Earth, oceans and atmosphere. These are currently calculated on the basis of the current riverine input to the oceans which may be may seriously perturbed by short-term climatic change. Past changes in seawater composition will be reconstructed from its hydrothermal imprint on the ocean crust.

Deep drilling in island arcs will test the hypothesis that the continental crust is produced by subduction zone processes, reveal the arc hydrothermal contribution to oceanic geochemical budgets and associated resources, and study the major seismic and volcanic hazards posed by subduction zones.

The developments in sub-seafloor observatories now permit observations on phenomena related to mechanical, hydrogeological, thermal, chemical and microbiological processes in real time as well as time-series sampling of fluids. Borehole observations on fluids in the sub -seafloor are particularly important as they transport heat, chemicals, nutrients and microbes, lubricate faults and their hydraulic transients are sensitive to deformation events.

The installation of networked down-hole observatories to form a long-term real-time monitoring system in the NanTroSEIZE experiment will return unprecedented detail concerning seismogenic processes, particularly the newly discovered episodic tremor, low frequency and slow slip events. Borehole observatories will be important in monitoring hydrothermal circulation in the ocean crust and its sedimentary veneer and in arc settings, as well as assessing both the geohazard and possible resource in the dynamic gas hydrate accumulations. Continuous passive monitoring and active experiments with natural or artificial perturbations reveal hydrological architectures and deformation processes. The development of cabled networks of such observatories will enable real-time observations with the potential of early warning systems for geohazards associated with earthquakes and tsunamis.

The results from drilling will make critical contributions to interdisciplinary research programs on Earth processes including work on modelling future climate change, ecology, evolutionary processes and the interactions between the biosphere and the Earth’s surface environment, solid Earth dynamics, and the many processes in the oceans that exert fundamental controls on climate, provide resources and generate major hazards.

The new drilling program will exploit the investments in drill ships and downhole instrumentation as well as strategic developments in mounting of drilling expeditions during the IODP. The non-riser drill ship, Joides Resolution, supplied and operated by the US National Science Foundation, was refurbished in 2008. The riser drill ship, Chikyu, supplied and operated by JAMSTEC commenced IODP operations in 2007 and is capable of drilling very deep holes and in holes in unstable and overpressured formations. The European Consortium for Ocean Research Drilling supplies specialist rigs which allows drilling in locations inaccessible to the Joides Resolution or Chikyu, such as shallow water or ice-covered seas.

1: Introduction

1.1 Scientific Overview

Exploration of the oceans is key to understanding the dynamics of the solid Earth and its surface environment. The oceans cover the majority of active plate boundaries and play a central role in controlling the Earth's climate. Only the deep oceans preserve the complete sedimentary sequences which provide the continuous temporal records of Earth processes, critical for model formulation and testing. Drilling in the oceans is essential for recovery of these records as well as for sampling, observing and experimenting on a whole series of active Earth processes.

The results of previous drilling in the oceans form the basis of much of our present understanding of the Earth and environmental sciences. The initial phases of ocean drilling verified plate tectonics and established research on palaeoclimate. The latter has revealed the magnitude and rapidity of climate change, the role of ocean circulation in moderating climate and the important interactions between the oceanic biosphere and climate. Other key contributions from drilling include elucidating the structure of the ocean crust, the recognition of hydrothermal fluid flow in diverse marine settings and its significance for both tectonics and global geochemical cycles, the presence and dynamic nature of gas hydrates, and the diversity and extent of the sub-seafloor microbial ecology.

The IODP2 is needed to answer questions of fundamental scientific significance, urgent questions as to how society should manage the global environment and resources and questions related to major geological hazards.

Scientific curiosity about the evolution and workings of the Earth is integral to society. Such research may reveal unexpected hazards and discover new resources. Because Earth processes are inter-dependent, the fundamental questions related to the workings of the Earth underpin the urgent questions as to how society manages its environment and resources and how it copes with geohazards. Despite the success of plate tectonics in describing the surface motions of the planet, we still do not fully understanding the gross structure and composition of the Earth, convection within the mantle and how melt is formed, moves and crystallises to form the crust. How the continents are formed and how they deform in orogenic belts remain controversial. There are major uncertainties in the fluxes of key chemical species between the solid Earth and the oceans and thus on controls on ocean chemistry and climate, yet ocean chemistry underpins climatic processes on all time scales. The biosphere dominates carbon cycling and the fluxes of many other chemical species between geological reservoirs and moderates the surface environment in the process. The interactions between the evolution of the biosphere and the chemistry of the oceans and atmosphere are poorly understood, as is the extent of the biosphere, particularly the operation of the deep biosphere which extends more than a kilometre below the sediment surface. IODP2 drilling over the next decade will make key contributions to resolution of these fundamental Earth science research topics.

Anthropogenic CO2 emissions and the consequent global warming, ocean acidification and sea level rise are recognised as major threats to the global environment. Ocean drilling will make essential contributions to the debate concerning the consequences of anthropogenic CO2 emissions. It is possible to calculate how rising atmospheric CO2 will increase radiative forcing with some confidence. However modelling the consequences is much more difficult as it is hard to predict the behaviour of complex physical systems where unexpected forcings and feedbacks invariably modify their behaviour. The only data we have to test our models of future climate and evaluate potential instabilities in climate states are the records of past change. Previous ocean drilling results are already being used in this way. For example estimates of past temperatures and atmospheric CO2 levels are being used to infer climate sensitivity for comparison with current predictions, past variations in sealevel constrain the instability of icesheets and the Palaeocene-Eocene event 55 Myr ago allows us to observe the impact on climate and ocean acidification of a release of carbon comparable to anthropogenic emissions. However the modelling of paleoclimate is in its infancy and past changes in sea level and major climatic shifts, including the glacial-interglacial transitions and the shorter time-scale Dansgaard-Oeschger events within the last glacial cycle are still incompletely understood. The latter, with warming phases of 5 to 8°C in 40 years in some places, is an example of past climatic instability on a time scale of societal concern.

Geological hazards arising from active tectonics including earthquakes, volcanos and landslides present immediate risks to a significant proportion of the global population as well as the global economy. Population growth, pressure on land use and the increasing inter-dependence of the global economy on travel and trade are increasing both the magnitude and spread of the impacts of geological hazards, as seen in the consequences of the eruption of the small volcano at Eyjafjallajökull in Iceland in April 2010. Drilling is central to evaluating the risks and understanding the driving mechanisms behind geological hazards. The likelihood of volcanic and submarine landslide hazards is best evaluated from the complete records that can only be recovered by drilling ocean sediments. Much of the risk arises from subduction zones and the IODP has embarked on an ambitious project (NanTroSEIZE) to drill into the seismogenic zone in the Nankai Trough to investigate the source and mechanisms of the most damaging earthquakes. This project, which will continue into the new program, will combine sampling of the seismogenic zone with installation of borehole observatories for continuous monitoring of strain, hydrology and seismicity.

IODP2 will research i) the processes which moderate the Earth’s surface environment and climate, ii) the biosphere and its interactions with major Earth processes and iii) solid Earth dynamics and the consequent tectonic and geochemical impacts at the Earth’s surface. The development of active observation and experimentation in drillhole observatories is an increasingly important component of ocean drilling research. The Science Plan for IODP2 is organised under these four major themes.

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