1:45 PM - 3:15 PM
[SCG52-P05] “Megacore” and Ashura-type multiple corers equipping 3D printed Core Catcher tested on KH-23-1 cruise - New methods for undisturbed sampling of surface sediment.
Keywords:Tokara Islands, submarine sediment
New methods of undisturbed sampling of submarine surface sediment were tested on the KH-23-1 cruise conducted around the Tokara Islands in 2023/1-2. We provide a brief overview of the results.
<3D printed Core Catcher equipped on Ashura-type Multiple Corer >
an Ashura-type multiple corer (AS) is widely used as a pilot corer for free-fall-type core samplers. The sediment is held by an arm equipped with AS. However, there were some problems: the structure is complicated and may malfunction, and the arm may not function sufficiently on hard bottom material such as sandy sediment, resulting in a low recovery rate. On the KH-23-1 cruise, a resin core catcher printed by a 3D printer was operated. The core catcher was attached to the end of the sampling tube of the AS with the arm removed and used as a pilot corer for the large-diameter gravity corer (5 m length). As a result, the core catcher successfully recovered over 30 cm length of poorly sorted fine to very fine sandy sediment, which is difficult to recover with normal handling of AS.
< ”Megacore” Sampling from the Box Corer>
The box corer is a surface sampler that can collect a large volume of sediments from the seafloor in an area of 40 cm x 40 cm x a maximum of 50 cm depth with almost no disturbance. Normally, sliced samples and/or sub-core samples of less than 10 cm in diameter are taken on board. On the KH-23-1 cruise, large sized subsample named "Megacore" of 20 cm in diameter was taken from surface sediments obtained from the box corer and brought back to the laboratory for non-destructive analysis, including CT imaging. This allowed us to observe a variety of sedimentary structures, including spatial distribution patterns of benthic burrows on a scale of several tens of centimeters, lateral continuity of sedimentary structures such as oblique stratigraphy, and partial disappearance of coarse-grained layers due to bioturbation.
<3D printed Core Catcher equipped on Ashura-type Multiple Corer >
an Ashura-type multiple corer (AS) is widely used as a pilot corer for free-fall-type core samplers. The sediment is held by an arm equipped with AS. However, there were some problems: the structure is complicated and may malfunction, and the arm may not function sufficiently on hard bottom material such as sandy sediment, resulting in a low recovery rate. On the KH-23-1 cruise, a resin core catcher printed by a 3D printer was operated. The core catcher was attached to the end of the sampling tube of the AS with the arm removed and used as a pilot corer for the large-diameter gravity corer (5 m length). As a result, the core catcher successfully recovered over 30 cm length of poorly sorted fine to very fine sandy sediment, which is difficult to recover with normal handling of AS.
< ”Megacore” Sampling from the Box Corer>
The box corer is a surface sampler that can collect a large volume of sediments from the seafloor in an area of 40 cm x 40 cm x a maximum of 50 cm depth with almost no disturbance. Normally, sliced samples and/or sub-core samples of less than 10 cm in diameter are taken on board. On the KH-23-1 cruise, large sized subsample named "Megacore" of 20 cm in diameter was taken from surface sediments obtained from the box corer and brought back to the laboratory for non-destructive analysis, including CT imaging. This allowed us to observe a variety of sedimentary structures, including spatial distribution patterns of benthic burrows on a scale of several tens of centimeters, lateral continuity of sedimentary structures such as oblique stratigraphy, and partial disappearance of coarse-grained layers due to bioturbation.