Record Details

Leg 179 summary

DRS at CSIR-National Institute of Oceanography

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Title Leg 179 summary
 
Creator Pettigrew, T.J.
Casey, J.F.
Miller, D.J.
Araki, E.
Boissonnas, R.
Busby, R.
Einaudi, F.
Gerdom, M.
Guo, Z.P.
Hopkins, H.
Myers, G.
Rao, D.G.
Shibata, T.
Thy, P.
 
Subject deep-sea drilling
hole recentry
instrument platforms
gabbros
basalts
 
Description Ocean Drilling Program (ODP) Leg 179 set out with two primary objectives. These objectives were (1) testing the recently developed hammer drill-in casing system on the Atlantis Bank, Southwest Indian Ridge (SWIR), and (2) drilling a cased reentry hole into basaltic basement on the Ninetyeast Ridge to allow future installation of an ocean floor geophysical observatory, the Ninetyeast Ridge Observatory (NERO). Both of these objectives were accomplished during Leg 179. Because of contingencies developed during the leg, certain ancillary objectives were not accomplished, but one contingency drilling site was cored on the Atlantis Bank, SWIR. Hammer drill testing was completed on the Atlantis Bank at Sites 1104 and 1106. These tests provide a wealth of information regarding the viability of the system as a new tool for investigating the solid earth. Although the testing was not completed as planned during Leg 179, design changes as a result of tests that were completed are already under way. Hole 1105A penetrated to a depth of 158 m on the Atlantis Bank, 118.43 m of gabbroic rock representing 82.8% of the cored section was recovered. Gabbro, olivine gabbro, oxide gabbro, and felsic rocks were recovered. Together with logging results that included Formation MicroScanner images of the borehole, this recovery provides a rather complete coverage of the rock types and a comprehensive view of pseudostratigraphy in the gabbroic section that appears related to nearby Hole 735B, 1.2 km away. Second primary objective specifically included drilling a single hole as deep as possible into basement, and installing a reentry cone and casing beyond basement to prepare the Ninetyeast Ridge site as an ocean-bottom observatory
 
Date 2009-01-10T11:15:57Z
2009-01-10T11:15:57Z
1999
 
Type Book Chapter
 
Identifier Proceedings of the Ocean Drilling Program, Initial Reports Volume 179. Hammer Drilling and NERO covering Leg 179 of the cruises of the Drilling Vessel JOIDES Resolution Atlantis Bank, Southwest Indian Ridge, ed. by: Scroggs, J.M. 1-26p.
http://drs.nio.org/drs/handle/2264/1788
 
Language en
 
Rights Copyright [1999]. All efforts have been made to respect the copyright to the best of our knowledge. Inadvertent omissions, if brought to our notice, stand for correction and withdrawal of document from this repository.
 
Publisher ODP, Texas A and M Univ., USA