A hand-operated, 180° rotating-scoop sediment sampler

Abstract

A hand-operated, rotating-scoop sediment sampler (HORS) has been developed for coarse-grained, shallow-marine sediment. Design of the 10 kg HORS was inspired by the 60 kg, winch-operated Shipek sampler which also has a 180° rotating scoop. At one-sixth of the Shipek mass, the HORS typically collects about one-sixth as much sediment. The HORS is recommended only if a winch is unavailable for a Shipek grab sampler. Grab samplers without a 180° rotating scoop rely on one or two pairs of jaws which close toward the center along arcs of 90°. These center-closing devices commonly fail to sample coarse sediment because a large grain, e.g. a shell fragment, impedes closure and allows the sample to escape during ascent. Center-closing jaws which meet rather than overlap eventually fail to meet completely because of wear along the jaw edge or misalignment. All grab samplers, including rotating-scoop types, may induce some loss of the finest fraction and so are best reserved for reconnaissance work. The sampler described herein has facilitated reconnaissance of the modern equivalent of oolitic ironstone in the southeastern Caribbean.