In a pair of expeditions to the South China Sea aboard the JOIDES Resolution, scientists will explore the mechanisms of lithosphere extension during continental breakup by drilling four sites across a 300-km wide zone of highly extended, seaward thinning crust. The expedition will core through thick sedimentary sections to look for serpentinized mantle in the underlying continent-ocean-transition basement zone. The presence or absence of serpentinite will support competing models of plate rupture. Study of the sedimentary sections will constrain the timing of rifting, rate of extension, and crustal subsidence that resulted the present-day South China Sea, leading to a new understanding of how marginal basins begin and grow. daily reports
Expedition 366 to the western Pacific Ocean aboard the JOIDES Resolution investigated the geochemistry, tectonics, and biology in an active subduction zone by coring the summits and flanks of serpentinite mud volcanoes on the forearc of the Mariana system, a non-accretionary convergent plate margin. Re-entry cones were installed in cased boreholes at three sites to provide infrastructure for future installation of long-term borehole monitoring systems. The sediment, rock, and fluid samples obtained during this expedition will be used to understand mass transport and geochemical cycling, track the spatio-temporal variability of subduction-related fluids and water-rock interactions, and study how physical properties and dehydration might control seismicity in non-accretionary convergent forearc systems.
Small variations in the modern-day Western Pacific Warm Pool, a large stable ocean region with tropical sea-surface temperatures located NE of Papua New Guinea, are known to perturb global atmospheric circulation patterns and are correlated with fluctuations in ocean conditions that modulate weather. Expedition 363 aboard the JOIDES Resolution explored the geological history of the Western Warm Pool and its spatiotemporal variability from the middle Miocene to recent times. Sediment cores were taken to provide high-resolution records comparable to those from cave deposits and ice cores, allowing scientists to infer the role of the WP Warm Pool in Holocene climate variability, its relation to monsoon periods and the Indonesian Throughflow current during the Pliocene-Pleistocene, and ocean conditions and chemistry since the middle Miocene (approximately 15 million years ago).
Pushing the limits of knowledge about life on Earth, scientists aboard Chikyu and at the Kochi Core Center are exploring the complex response to temperature of microbial communities living in the seafloor near the Muroto Transect, a high-heat flow area of the Nankai Trough. The expedition will drill the entire sedimentary depth and into ~50 m of basaltic basement for a total target depth of 1210 m beneath seafloor, retrieving core samples at various temperature intervals and logging the temperature depth profile in detail. The team will also install a Temporary Temperature Observatory (TTO), a complex string of about 50 sensors whose exact design will be guided the detailed formation structure revealed by preliminary analysis of the cores taken during drilling. daily reports * science FAQs * scientist blogs
The December 2004 Indian Ocean tsunami caused by a Mw 9.2 earthquake devastated coastal communities, killing over 250,000. IODP Expedition 362 aims to examine the role of seafloor sediments and their potential effect on seismogenesis and tsunamogenesis in this part of the North Sumatra seismogenic zone. The rupture area of the 2004 earthquake was focused beneath a distinctive plateau of the accretionary prism, where input materials are primarily a thick sequence of sediments related to the Bengal-Nicobar fan. Expedition 362 will sample these input materials at two drill sites, analyze their properties, and log downhole temperature and pressure conditions to study sediment deposition rates, diagenesis, physical properties, and fluid composition, leading to a clearer picture of how input sedimentary rocks affect the plate boundary slip system and implications for seismic slip here and in similar subduction margins. facebook * Twitter * ship reports * press release
IODP Expedition 364 has successfully completed its drilling phase at the unique Chicxulub impact crater near Mexico's Yucatan Peninsula, which is directly linked to the K-Pg mass extinction 66 million years ago. The final depth was 1335 meters below seafloor. The samples and data obtained will address the formation of large impact craters on Earth and other planets, and the effects of large impacts on Earth's environment and ecology. The Chicxulub impact crater is the best-preserved large impact structure on Earth, and the only terrestrial crater with a global ejecta layer. This expedition aims to drill into the impact structure to recover cores from, and above, the peak ring. This will address several questions, including: 1) what rocks comprise a topographic peak ring and how are peak rings formed; 2) how are rocks weakened during large impacts to allow them to collapse and form relatively wide, flat craters; 3) what caused the environmental changes that led to a mass extinction and what insights arise from biologic recovery in the Paleogene; and 4) what effect does a large impact have on the deep subsurface biosphere, and can impact events generate habitats for chemosynthetic life? The expedition will drill and core a single 1500 m deep borehole at site about 30km northwest of Progreso, Mexico, on the Yucatan shelf, Gulf of Mexico. Alberta article * SoundCloud (5 min) * facebook