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Deep-sea hammer corer

Objective



The provision of long, undisturbed cores of all types of sediments from shallow as well as deep water is of paramount importance for the reconstruction of the history of the oceans and of climate changes, as well as for various technical purposes such as drilling site surveys and slope stability predictions.

While considerable progress has been made, during the last years, in laboratory techniques for sediment analysis, relatively simple sampling devices still prevail, and samples collected so far usually represent surface-near layers only. This is especially true for deep waters, where core recovery from gravity corers seldom exceed 10 meters. Giant piston corers partially solve the problem of deep penetration, but they are difficult to control and not suitable for all types of sediments. During coring and core treatment typical physical and chemical parameters of the sediments may be lost. Therefore, a more precise characterization of the subsurface requires in-situ testing.

The objective of the project is the design and development of a heavy-duty sediment corer. The system is designed to recover up to 30 m long sediment cores from water depths down to 5,000 m. It consists mainly of two units: a frame which is connected through an umbilical to the support vessel and a sledge which contains a hammer to drive the core barrel into the soil. The above configuration ensures that the sledge is decoupled from the ship's movements during coring. Penetration is supported by water flushing and a stationary piston.
The system will also provide the possibility to perform measurements of in-situ geotechnical parameters of the seabed and for recovering pore water samples by replacing the lower most section of the core barrel by a testing probe.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Geomar Technologie GmbH
Address
Wischhofstraße 1-3
24148 Kiel
Germany

Participants (4)

Federal Institute for Geosciences and Natural Resources
Germany
Address
Stilleweg 2
30655 Hannover
NERC British Geological Survey
United Kingdom
Address
Nicker Hill
NG12 5GG Keyworth
NORWEGIAN GEOTECHNICAL INSTITUTE
Norway
Address
Sognsveien 72
0806 Oslo
Seabed BV
Netherlands
Address

1560 AD Krommenie