The MoHole: A Crustal Journey and Mantle Quest, Workshop in Kanazawa, Japan, 35 June 2010

Ildefonse, Benoı̂t; Abe, Natsue; Blackman, Donna K.; Canales, J. P.; Isozaki, Yoshio; Kodaira, Shuichi; Myers, Greg; Nakamura, Kozo; Nedimović, M. R.; Skinner, A. C.; Seama, Nobukazu; Takazawa, Eiichi; Teagle, D. A. H.; Tominaga, Masako; Umino, Susumu; Wilson, Douglas S.; Yamao, Masaoki

doi:10.2204/iodp.sd.10.07.2010

Cited by 6 publications

(5 citation statements)

References 12 publications

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“…These accretion models can be used for predicting contrasted vertical trends of petrology, deformation, cooling rates, and alteration in the gabbroic crust (e.g., Ildefonse et al., 2010), which still remain to be fully tested in ophiolites and by deep drilling in intact fast‐spread crust (e.g., Ildefonse et al., 2014; Teagle et al., 2012). Coogan et al.…”

Section: Introductionmentioning

confidence: 99%

A Reference Section Through Fast‐Spread Lower Oceanic Crust, Wadi Gideah, Samail Ophiolite (Sultanate of Oman): Insights From Crystallographic Preferred Orientations

et al. 2021

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Based on marine geophysics, seafloor geology, and ophiolite studies, the classical picture of a uniformly layered oceanic crust (with basaltic lava flows, basaltic sheeted dikes, and gabbros, from top to bottom) emerged in the early 1970s (Anonymous, 1972). About 50 years later, our vision of the architecture of the ocean crust has considerably evolved, with a continuously growing understanding of its variability at the global scale. This variability results from various modes of accretion that are controlled by magma supply to the ridge, which in turn is related on the first order to spreading rate (e.g.

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Section: Introductionmentioning

confidence: 99%

A Reference Section Through Fast‐Spread Lower Oceanic Crust, Wadi Gideah, Samail Ophiolite (Sultanate of Oman): Insights From Crystallographic Preferred Orientations

et al. 2021

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“…Therefore, this oceanic lithosphere is older and colder than would be expected for this bathymetric depth alone. For this reason, the northern Hawaiian Arch is one of the feasible candidates for Project Mohole drilling (Ildefonse et al 2010), a plan proposed in 1957 to drill a hole completely through the crust beneath the ocean (Hess 1959). However, the crustal structure around the islands is potentially affected by hotspot volcanism, making it difficult to target "typical" oceanic crust for drilling.…”

Section: Introductionmentioning

confidence: 99%

Active-source seismic survey on the northeastern Hawaiian Arch: insights into crustal structure and mantle reflectors

Ohira

Kodaira

Moore

et al. 2018

Earth Planets Space

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Seismic refraction and multi-channel seismic reflection surveys were conducted on the northeastern Hawaiian Arch to examine the effect of hotspot volcanism on the seismic structure of the crust and uppermost mantle. The crustal thickness deduced from the refraction data was typical for oceanic crust, which suggests that magmatic underplating does not occur, at least in our survey area, although the crustal seismic velocity may be influenced by flexure of the lithosphere on the arch. We identified high P-wave velocities (~ 8.65 km/s) in the uppermost mantle parallel to the paleo-seafloor spreading direction, which indicates that the shallower mantle structure immediately below the Moho preserves the original structure formed at a mid-ocean ridge. Moreover, we observed wide-angle reflection waves at large offsets in ocean-bottom seismometer records. The travel time analysis results showed that these waves were reflected from mantle reflectors at depths of 30-85 km below the seafloor, which are considered to represent heterogeneities consisting of frozen melts created during the cooling of the plate.

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“…Previous scientific ocean drilling has demonstrated that bacteria, archaea, fungi, and viruses inhabit marine sediment (D'Hondt et al, 2004;Inagaki et al, 2006Inagaki et al, , 2015Orsi et al, 2013;Engelhardt et al, 2014;Liu et al, 2017;Hoshino et al, 2020) and the shallow basaltic aquifer that underlies marine sediment (Cowen et al, 2003;Lever et al, 2013;Ivarsson et al, 2016;Jørgensen and Zhao, 2016;Nigro et al, 2017;Quemener et al, 2020;Suzuki et al, 2020). A few studies have reported evidence of microbial communities in North Atlantic gabbroic lower crust exposed by faulting (Alt et al, 2007;Mason et al, 2010;Li et al, 2020).…”

Section: Nature and Extent Of Life In The Oceanic Crustmentioning

confidence: 99%

Workshop report: Exploring deep oceanic crust off Hawai`i

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Abstract. For more than half a century, exploring a complete sequence of the oceanic crust from the seafloor through the Mohorovičić discontinuity (Moho) and into the uppermost mantle has been one of the most challenging missions of scientific ocean drilling. Such a scientific and technological achievement would provide humankind with profound insights into the largest realm of our planet and expand our fundamental understanding of Earth's deep interior and its geodynamic behavior. The formation of new oceanic crust at mid-ocean ridges and its subsequent aging over millions of years, leading to subduction, arc volcanism, and recycling of some components into the mantle, comprise the dominant geological cycle of matter and energy on Earth. Although previous scientific ocean drilling has cored some drill holes into old (> 110 Ma) and young (< 20 Ma) ocean crust, our sampling remains relatively shallow (< 2 km into intact crust) and unrepresentative of average oceanic crust. To date, no hole penetrates more than 100 m into intact average-aged oceanic crust that records the long-term history of seawater–basalt exchange (60 to 90 Myr). In addition, the nature, extent, and evolution of the deep subseafloor biosphere within oceanic crust remains poorly unknown. To address these fundamentally significant scientific issues, an international workshop “Exploring Deep Oceanic Crust off Hawai`i” brought together 106 scientists and engineers from 16 countries that represented the entire spectrum of disciplines, including petrologists, geophysicists, geochemists, microbiologists, geodynamic modelers, and drilling/logging engineers. The aim of the workshop was to develop a full International Ocean Discovery Program (IODP) proposal to drill a 2.5 km deep hole into oceanic crust on the North Arch off Hawai`i with the drilling research vessel Chikyu. This drill hole would provide samples down to cumulate gabbros of mature (∼ 80 Ma) oceanic crust formed at a half spreading rate of ∼ 3.5 cm a−1. A Moho reflection has been observed at ∼ 5.5 km below the seafloor at this site, and the workshop concluded that the proposed 2.5 km deep scientific drilling on the North Arch off Hawai`i would provide an essential “pilot hole” to inform the design of future mantle drilling.

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The MoHole: A Crustal Journey and Mantle Quest, Workshop in Kanazawa, Japan, 35 June 2010

Cited by 6 publications

References 12 publications

A Reference Section Through Fast‐Spread Lower Oceanic Crust, Wadi Gideah, Samail Ophiolite (Sultanate of Oman): Insights From Crystallographic Preferred Orientations

A Reference Section Through Fast‐Spread Lower Oceanic Crust, Wadi Gideah, Samail Ophiolite (Sultanate of Oman): Insights From Crystallographic Preferred Orientations

Active-source seismic survey on the northeastern Hawaiian Arch: insights into crustal structure and mantle reflectors

Workshop report: Exploring deep oceanic crust off Hawai`i

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The MoHole: A Crustal Journey and Mantle Quest, Workshop in Kanazawa, Japan, 35 June 2010

Cited by 6 publications

References 12 publications

A Reference Section Through Fast‐Spread Lower Oceanic Crust, Wadi Gideah, Samail Ophiolite (Sultanate of Oman): Insights From Crystallographic Preferred Orientations

A Reference Section Through Fast‐Spread Lower Oceanic Crust, Wadi Gideah, Samail Ophiolite (Sultanate of Oman): Insights From Crystallographic Preferred Orientations

Active-source seismic survey on the northeastern Hawaiian Arch: insights into crustal structure and mantle reflectors

Workshop report: Exploring deep oceanic crust off Hawai`i

Contact Info

Product

Resources

About

The MoHole: A Crustal Journey and Mantle Quest, Workshop in Kanazawa, Japan, 35 June 2010