In:
Scientific Drilling, Copernicus GmbH, Vol. 26 ( 2019-12-02), p. 47-58
Abstract:
Abstract. The architecture, formation, and modification of oceanic plates are
fundamental to our understanding of key geologic processes of the Earth.
Geophysical surveys were conducted around a site near the Hawaiian Islands
(northeastern Hawaiian North Arch region; Hawaiian North Arch hereafter),
which is one of three potential sites for an International Ocean Discovery
Program mantle drilling proposal for the Pacific plate that was submitted in
2012. The Hawaiian North Arch site is located in 78–81 Ma Cretaceous crust,
which had an estimated full spreading rate of 7–8 cm yr−1. This site fills
a major gap in our understanding of oceanic crust. Previously drilling has
been skewed to young or older crust (〈15 or 〉110 Ma)
and slow-spread crust. P-wave velocity structure in the uppermost mantle of the Hawaiian North Arch shows a strong azimuthal anisotropy, whereas Moho reflections below the basement are variable: strong and continuous, weak, diffuse, or unclear. We assume that the strength of the Moho reflection is related to the aging of the oceanic plate. The Hawaiian volcanic chain (200 km to the southwest of the proposed drill site) and the nearby North Arch
magmatism on the proposed Hawaiian North Arch sites might also have affected
recognition of the Moho via deformation and/or magma intrusion into the
lower crust of the uppermost mantle. This workshop report describes
scientific targets for 2 km deep-ocean drilling in the Hawaiian North Arch
region in order to provide information about the lower crust from unrecovered
age and spreading rate gaps from previous ocean drillings. Other scientific
objectives to be achieved by drilling cores before reaching the target depth
of the project are also described in this report.
Type of Medium:
Online Resource
ISSN:
1816-3459
DOI:
10.5194/sd-26-47-2019
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2019
detail.hit.zdb_id:
2207632-3
detail.hit.zdb_id:
2207618-9
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