Search

The Integrated Ocean Drilling Program, an international collaboration of Earth, ocean, and life scientists, commenced on 1 October 2003 (IODP; www.iodp.org). Building on the successes of previous scientific ocean drilling programs, the IODP offers scientists worldwide unprecedented opportunities to address a vast array of scientific problems in all submarine settings.The scientific advisory structure of the proposal-driven IODP recently planned the inaugural drilling expeditions, targeting critical scientific problems in the eastern Pacific, central Arctic, and north Atlantic Oceans in 2004 and 2005 (Figure 1, Table 1). Co-led by Japan and the United States, with initial, significant contributions from the European Consortium for Ocean Research Drilling (ECORD),the IODP is guided by an initial science plan, “Earth, Oceans, and Life” (wwwiodp.org/isp.html), developed with broad input from the international geoscientific community. For the first time, scientists will have permanent riser and non-riser drilling vessels and mission-specific capabilities such as drilling barges, and jack-up rigs for shallow water and Arctic drilling at their disposal. Japan is providing the new riser vessel, Chikyu,i the IODP beginning in 2006; the United States is supplying the non-riser drilling vessel, currently ,JOIDES Resolution,, beginning in 2004; and the ECORD is furnishing mission-specific platforms, also beginning in 2004.

Australia is an island nation with about two thirds of its jurisdiction underwater. On 25 May 2012, Australia instituted the Seas and Submerged Lands (Limits of Continental Shelf) Proclamation 2012, confirming areas of seabed where Australia has exclusive rights to explore and exploit marine resources. This proclamation follows recommendations by the Commission on the Limits of the Continental Shelf, a body established under the United Nations Convention on the Law of the Sea, confirming Australia's entitlement to extended continental shelf, i.e., that beyond 200 nautical miles from the coastline, of some 2.56 million square kilometers, excluding Australian Antarctic Territory [Symonds et al., 2009] (Figure 1a).

[1] The Ontong Java Plateau (OJP; see Figure 1a), in the western equatorial Pacific Ocean, is one of the largest oceanic plateaus on Earth, covering 1.86 million square kilometers—equivalent to roughly one third of the contiguous United States [Coffin and Eldholm, 1994]. This voluminous plateau is thought to have formed about 120 million years ago and to have caused significant global environmental changes; however, a consensus has not been reached on how the OJP formed. Competing theories include formation through a mantle plume, a meteor impact, and fast spreading ridges. Detailed knowledge of the OJP's crustal and upper mantle structure is necessary to help distinguish among existing models and to develop new models of how the OJP formed. Previous seismic studies acquired data by exploding charges at the ocean's surface and, through seismic analyses of travel times, deducing horizons of reflections and refractions below the ocean floor. However, most of these studies used relatively low energy shots and sparse source and receiver intervals and thus were unable to unambiguously determine the depth of the crust-mantle boundary.

An international, multidisciplinary community workshop convened to define scientific projects for the next decade of scientific ocean drilling utilizing unique capabilities afforded by the drilling vessel Chikyu ("Earth" in Japanese). The meeting, attended by 397 participants from 21 countries, featured 10 keynote lectures. Participants in working groups identified important projects that are fundamental to understanding the Earth system and that require deep penetration of the seafloor.

Call me Moby. The dream of every marine acoustician and seismologist is to image the ocean, the seafloor, and the subseafloor from the perspective of a whale's ear or, if the abyss weren't utterly dark, a fish's eye. Peter Wille's ambitious and remarkable, yet idiosyncratic compilation of sound translated into visual images of the ocean realm is perhaps the next best thing. The meat of the volume and accompanying CD-ROM consists of 452 mostly fascinating, mostly color images, all helpfully indexed at the start of the book, representing the contributions of more than 120 scientists from 22 nations. Those latter two numbers produce shudders and tics, if not migraines, in anyone who's ever assembled a volume involving contributions from even an order of magnitude fewer contributors.

Earth history is punctuated by continents breaking apart and births of oceans, phenomena occurring today in places such as the high Arctic, East Africa/Red Sea, the Gulf of California, and the western Pacific near Papua New Guinea. The tectonic, magmatic, geodynamic, and sedimentary processes associated with continental rifting and breakup interact to produce a variety of margin styles of rifting and breakup, ranging from narrow to hyperextended margins, from weakly to strongly magmatic margins, and from sedimentstarved to thickly sedimented margins. The wide variety of styles has puzzled and inspired Earth scientists for generations, who have employed an increasingly diverse and sophisticated set of observational tools to investigate, and conceptual models to explain, continental rifting and breakup.

The Integrated Ocean Drilling Program (IODP), an international collaboration of Earth, ocean, and life scientists that began in 2003, offers scientists worldwide unprecedented opportunities to address a vast array of scientific problems in all submarine settings. Recently, the scientific advisory structure of the proposal-driven IODP scheduled drilling expeditions, targeting critical scientific problems in the Atlantic Ocean, Gulf of Mexico, and Pacific Ocean, for 2005 and early 2006 (Figure I, Table I). The IOPD, which is co-led by Japan and the United States, with strong contributions from the European Consortium for Ocean Research Drilling (ECORD) and China, is guided by an initial science plan, “Earth, Oceans, and Life” (www.iodp.org). For the first time, through the IODP, scientists have at their disposal both a riser (drilling vessel which has a metal tube surrounding the drill pipe that enables the return of drilling fluid and cuttings to the drill ship; the “riser” is attached to a “blow-out preventer” or shut-off device at the seafloor) and riserless drilling vessel (which lacks a riser pipe and blow-out preventer), as well as mission-specific capabilities such as drilling barges and jack-up rigs for shallow-water and Arctic drilling.

On 26 September 2003, a magnitude 8.0 earthquake, Earth's most powerful in 2.5 years, struck offshore Tokachi, Hokkaido, Japan, at 0450 local time. The hypocenter was at 40 km depth along the boundary of the Pacific and North American plates (www.jma.go.jp). The focal mechanism shows a reverse fault with a northwest-southeast compressional axis (P-axis) (see http://www.bosai.go.jp). Following the main shock, named “Heisei 15 Tokachioki-jishin,” seismic activity has continued in the region. As of 30 September, the largest aftershock was M7.1 on 26 September at 0608. Tsunamis were observed on the Pacific coast of Hokkaido and the Tohoku region, including waves of 1.2 m at Kushiro, 1.3 m at Urakawa, and 1.0 m at Hachinohe.

Marine geophysical data acquired aboard research vessels operated by academic institutions were critical in fomenting the plate tectonic revolution in Earth science over a generation ago. In the past 15 years, however, the gap between academic and industrial marine geophysical data acquisition and processing, especially seismic, has widened. In the United States, this perhaps reflects the fact that funding for academic ocean science research has fallen from 7% to less than

Continental margins are the Earth's principal loci for producing hydrocarbon and metal resourcessemi; for earthquake, landslide, volcanic, and climatic hazardssemi; and for the greatest population density. As such, margins are where the action is. Despite the societal and economic importance of margins, many of the mechanical, fluid, chemical, and biological processes that shape them are poorly understood. Progress is hindered by the sheer scope of the problems and by the spatial-temporal scale and complexities of the processes. To overcome these obstacles, the margins community has identified the outstanding scientific problems in continental margins research, and the MARGINS Program, a research initiative supported by the U.S. National Science Foundation (NSF), is promoting research strategies that redirect traditional approaches to margin studies.

During a 44-day expedition on board the Australian vessel Rig Seismic, scientists collected new information on the morphology of the Macquarie Ridge Complex (MRC), located at the boundary between the Pacific and Australian plates. In the joint venture, funded by the U.S. National Science Foundation and Australian Geological Survey Organization (AGSO), investigators from the two countries studied deformation in the area along the MRC, which includes the site of the largest earthquake of the 1980s (May 23, 1989, Mω=8.2). The researchers acquired ∼160,000 km2 of HAWAII MR1 (HIG acoustic wide-angle imaging instrument, mapping researcher 1) side-scan sonar/bathymetry images and ∼7000 km of 8-channel seismic reflection data (Figure 1). In addition, three ∼400-km gravity transects of the MRC were completed across the morphologic ridge and trench system. The transects were augmented by 96-channel seismic reflection imaging across the morphologic ridge and trench system. Gravity and magnetic data were collected during the entire survey.

Episodic magmatism has resulted in the emplacement of large igneous provinces (LIPs), including continental flood basalts and associated intrusives, volcanic/intrusive passive margins, oceanic plateaus, submarine ridges, ocean basin flood basalts, and seamount chains (Figure 1). LIPs represent major global events, whose genesis and evolution are directly linked to mantle dynamics. Recent research has documented important temporal, spatial, and compositional relationships among LIPs. Large volumes of lava and associated intrusives are commonly produced in short episodes and may be related to changes in rate and direction of plate motion. Exceptions include some submarine ridges that record persistent extrusion as a plume trail. Geochemical studies of rocks from these environments suggest lower to upper mantle sources for the magma, with regional variations due to mantle heterogeneities and the nature of the crust through which the magma passes.