Advanced dredge system in Japan for material science on oceanic bedrocks -New dredge system with acoustic transponder and/or deep sea TV camera—
Abstract
It is very important to recover geological samples including hard rocks and soft materials from ocean floor to investigate bedrocks itself as well as sea floor environment on the basis of the material scientific aspects. Dredge haul methods being a simple and easy way with low costs, have been widely used for recovering the bedrocks. One of author (TI) has been working on the dredge hauls during about 40 years on the several Japanese and American Research Vessels (R/Vs), that is, R/V Tansei Maru, R/V Hakuho Maru, R/V Yokosuka, and R/V Kairei as well as R/V Atlantis-II, R/V Melville (2 times), R/V Moana Wave, and R/V Thomas Thompson, respectively. He has been proposing the (1) ORI-TI type dredge system, which has been improved and still improving on the basis of the better ideas gathered from the above mentioned all cruises. The dredge systems in the US Research Vessels have been continuing the conventional and basic technical methods, that is, box type chin-bag dredge (within or without fishing net) and using tension-meter as well as pinger.
On the other hand, Japanese scientists have been recently improving the traditional dredge systems with active introduction of high technique, for example, (2) transponder system and/or (3) deep sea TV camera system during dredge hauls. (1) ORI-TI (Ocean Research Institute T. ISHII) type dredge system is composed of box type chain-bag dredge with steel bucket which can recover any sea bottom material including hard rocks as well as sand, mud and organisms(Ishii, 2017).(2) Acoustic transponder attached on the dredge wire can mention real-time position of the dredge system on monitor showing pre- surveyed bathymetric map in the navigation room, This system helps safe and reliable rock sampling (Machida et al, 2011). (3) Box-cage type dredge with installed deep sea TV camera system can record occurrence of bed rocks during dredge hauls (Sakamoto et al, 2017).- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.V23L0217I
- Keywords:
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- 3037 Oceanic hotspots and intraplate volcanism;
- MARINE GEOLOGY AND GEOPHYSICSDE: 3075 Submarine tectonics and volcanism;
- MARINE GEOLOGY AND GEOPHYSICSDE: 3618 Magma chamber processes;
- MINERALOGY AND PETROLOGYDE: 8428 Explosive volcanism;
- VOLCANOLOGY