Provenance and Dispersal Patterns of Sediments in the Turbidite Wedge of Nankai Trough

Underwood, MB; Orr, Robert D.; Pickering, KT; Taira, Asahiko

doi:10.2973/odp.proc.sr.131.105.1993

Cited by 48 publications

(42 citation statements)

References 80 publications

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“…Coring of the upper intervals at Site C0012 was likewise deferred until Expedition 333. Previous studies in the Nankai-Shikoku region showed that hemipelagic mud(stones) change in composition largely as function of depositional age (e.g., Chamley, 1980;Chamley et al, 1986;Underwood et al, 1993aUnderwood et al, , 1993bSteurer and Underwood, 2003;Guo and Underwood, 2012;Underwood and Guo, 2013). Hemipelagic sedimentation during the Miocene was dominated by expandable clay minerals (smectite group), whereas the proportions of detrital illite and chlorite increased steadily through the Pliocene and Quaternary.…”

Section: Introductionmentioning

confidence: 99%

Data report: clay mineral assemblages in the upper Shikoku Basin, results from IODP Expedition 333, Sites C0011 and C0012

Underwood¹,

Guo²

2017

Proceedings of the IODP

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This report summarizes the results of X-ray diffraction analyses of core samples from Integrated Ocean Drilling Program (IODP) Sites C0011 and C0012, offshore southwest Japan. We analyzed 211 specimens (<2 µm size fraction) recovered during IODP Expedition 333. Most of those samples come from the uppermost hemipelagic/pyroclastic facies (Unit I) of the Shikoku Basin, with a limited number from the volcanic turbidite facies (Unit II) and the pelagic clay facies (Unit V). Minerals of the smectite group are generally the most abundant. At Site C0011, the amount of smectite in the clay-size fraction of Unit I averages 40.8 wt% (standard deviation = 11.5) and increases downsection. Proportions of illite and chlorite average 36.4 and 15.5 wt%, respectively. Average contents of kaolinite and quartz are 3.6 and 3.7 wt%, respectively. At Site C0012 (Unit I), the amount of smectite averages 50.0 wt% (standard deviation = 13.5) and increases downsection. Averages for the other minerals in the clay-size fraction are illite = 31.8 wt%, chlorite = 10.1 wt%, kaolinite = 5.5 wt%, and quartz = 2.6 wt%. Most values of illite/smectite expandability fall between 60% and 70%, and there are no systematic changes downsection. Values of the illite crystallinity index are generally consistent with detrital sources that were exposed to anchizone metamorphic conditions.

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Section: Introductionmentioning

confidence: 99%

Data report: clay mineral assemblages in the upper Shikoku Basin, results from IODP Expedition 333, Sites C0011 and C0012

Underwood¹,

Guo²

2017

Proceedings of the IODP

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“…Kastner et al, 1993). The observed freshening is partly explained by in situ diagenesis (compaction and thermally driven smectite dehydration) but also suggests some episodic lateral fluid flow along one or more sediment horizons (Moore, Taira, Klaus, et al, 2001;Saffer and Bekins, 1998;Underwood et al, 1993).…”

Section: Heat and Fluid Flowmentioning

confidence: 89%

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2016

International Ocean Discovery Program Scientific Prospectus

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Determining factors that limit the biomass, diversity, and activity of subseafloor microbial communities is one of the major scientific goals to be addressed by scientific ocean drilling. In the International Ocean Discovery Program (IODP) T-Limit Project, we will drill and core at new boreholes in the immediate vicinity of Ocean Drilling Program (ODP) Sites 1173, 1174, and 808 off Cape Muroto, Japan, in the central Nankai Trough, where anomalously high heat flow regimes result in temperatures of 110° to 140°C at the sediment/basement interface. Because of their location in the trench (Site 1173) and landward protothrust zone of the Nankai Trough accretionary prism (Sites 808 and 1174), the sites have different geotectonic and thermal histories that have resulted in contrasting (bio)geochemical modes of hydrocarbon gas production and consumption. Although the upper temperature limit appears well constrained at relatively energy-rich hydrothermal vent systems at just above 120°C, it is unknown in energy-starved sedimentary subseafloor settings but is generally presumed to be lower and thus expected to be covered by our target sites. During the IODP TLimit Project, we aim to• Comprehensively study the factors that control biomass, activity, and diversity of microbial communities in a subseafloor environment where temperatures increase from ~30° to ~130°C and thus likely encompasses the biotic-abiotic transition zone; and • Determine geochemical, geophysical, and hydrogeological characteristics in sediment and the underlying basaltic basement and elucidate if the supply of fluids containing thermogenic and/or geogenic nutrient and energy substrates may support subseafloor microbial communities in the Nankai accretionary complex.Because of the D/V Chikyu's schedule, these scientific objectives cannot be achieved within a single expedition. During the first TLimit expedition (370), we will drill and retrieve core samples from sedimentary sections (200-1210 m below seafloor) and basement basalt (1210-1260 m below seafloor) at the protothrust site near ODP Site 1174 and measure temperatures in situ.

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“…Kastner et al, 1993). The observed freshening is partly explained by in situ diagenesis (i.e., compaction and thermally driven smectite dehydration) but also suggests some episodic lateral fluid flow along one or more sediment horizons (Moore, Taira, Klaus, et al, 2001;Saffer and Bekins, 1998;Underwood et al, 1993).…”

Section: Heat and Fluid Flowmentioning

confidence: 93%

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2017

Proceedings of the International Ocean Discovery Program

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International Ocean Discovery Program (IODP) Expedition 370 explored the limits of the biosphere in the deep subseafloor where temperature exceeds the known temperature maximum of microbial life (~120°C) at the sediment/basement interface ~1.2 km below the seafloor. Site C0023 is located in the protothrust zone in the Nankai Trough off Cape Muroto at a water depth of 4776 m, in the vicinity of Ocean Drilling Program (ODP) Sites 808 and 1174. In 2000, ODP Leg 190 revealed the presence of microbial cells at Site 1174 to a depth of ~600 meters below seafloor (mbsf ), which corresponds to an estimated temperature of ~70°C, and reliably identified a single zone of elevated cell concentrations just above the décollement at around 800 mbsf, where temperature presumably reached 90°C; no cell count data was reported for other sediment layers in the 70°-120°C range because the detection limit of manual cell counting for low-biomass samples was not low enough. With the establishment of Site C0023, we aimed to detect and investigate the presence or absence of life and biological processes at the biotic-abiotic transition utilizing unprecedented analytical sensitivity and precision. Expedition 370 was the first expedition dedicated to subseafloor microbiology that achieved time-critical processing and analyses of deep biosphere samples, conducting simultaneous shipboard and shore-based investigations.Our primary objective during Expedition 370 was to study the relationship between the deep subseafloor biosphere and temperature. We comprehensively studied the controls on biomass, activity, and diversity of microbial communities in a subseafloor environment where temperatures increase from ~2°C at the seafloor tõ 120°C and thus likely encompasses the biotic-abiotic transition zone. This included investigating whether the supply of fluids containing thermogenic and/or geogenic nutrient and energy substrates may support subseafloor microbial communities in the Nankai accretionary complex. To address these primary scientific objectives and questions, we penetrated 1180 m and recovered 112 cores of sediment and across the sediment/basalt interface. More than 13,000 samples were collected, and selected samples were transferred to the Kochi Core Center by helicopter for simultaneous microbiological sampling and analysis in laboratories with a superclean environment. In addition to microbiological measurements, we determined the geochemical, geophysical, and hydrogeological characteristics of the sediment and the underlying basement and installed a 13-thermistor sensor borehole temperature observatory into the borehole at Site C0023.

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Provenance and Dispersal Patterns of Sediments in the Turbidite Wedge of Nankai Trough

Cited by 48 publications

References 80 publications

Data report: clay mineral assemblages in the upper Shikoku Basin, results from IODP Expedition 333, Sites C0011 and C0012

Data report: clay mineral assemblages in the upper Shikoku Basin, results from IODP Expedition 333, Sites C0011 and C0012

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