ABSTRACT The majority of sediment acoustics research has focused to date on sediments with sand‐sized particles or smaller; measurements for sediments containing cobbles (6–26 cm) are rare. This paper presents the first measurements (to the authors’ knowledge) over a wide frequency range of compressional‐wave velocity and bulk density for a sediment with cobbles. The in situ velocity from inversion from wide‐angle reflection‐coefficient data at 0.4–2 kHz for cobbles suspended in sand is found here to be 1800 m/s with 95% credibility interval bounds of [1787–1828] m/s and for cobbles suspended in clay 1532 [1528–1536] m/s. Measured core velocities at 50 kHz and 200 kHz are lower for each sediment due to multiple scattering. The in situ bulk density for cobbles suspended in sand is 2.25 [2.21–2.28] g/cm3 and for cobbles suspended in clay 1.83 [1.78–1.87] g/cm3. Though cobbles in the upper few metres of sediment may be considered unusual on the mid‐shelf at mid‐latitudes, they appear to be present over tens of square kilometres on the Malta Plateau in a several metre thick layer starting at about 1 m below seafloor. In fact, geologic process considerations suggest that cobbles may be generally more common in mid to outer shelf environments than the paucity of measurements would suggest. Increased interest in the Arctic continental shelf environment, where pebbles and cobbles are expected to be prevalent, provides an additional motivation for this work.

中文翻译：

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用鹅卵石和鹅卵石对海洋沉积物进行声学测量

摘要 迄今为止，大多数沉积物声学研究都集中在具有沙粒或更小的颗粒的沉积物上。对含有鹅卵石（6-26 厘米）的沉积物的测量很少见。本文介绍了（据作者所知）在宽频率范围内对带有鹅卵石的沉积物进行压缩波速度和体积密度的首次测量。从 0.4-2 kHz 的广角反射系数数据反演的原位速度对于悬浮在沙子中的鹅卵石在这里发现为 1800 m/s，95% 可信区间界限为 [1787-1828] m/s，对于悬浮在粘土中的鹅卵石 1532 [1528–1536] m/s。由于多次散射，每种沉积物在 50 kHz 和 200 kHz 下测得的核心速度较低。悬浮在沙子中的鹅卵石的原位堆积密度为 2.25 [2.21–2.28] g/cm3，悬浮在粘土中的鹅卵石为 1.83 [1。78–1.87] g/cm3。尽管在中纬度的中陆架上，沉积物上部几米中的鹅卵石可能被认为是不寻常的，但它们似乎存在于马耳他高原上数十平方公里的范围内，从海底以下约 1 m 处开始形成数米厚的层. 事实上，地质过程的考虑表明，鹅卵石在中到外大陆架环境中可能比缺乏测量所表明的更常见。对北极大陆架环境的兴趣增加，预计鹅卵石和鹅卵石将普遍存在，为这项工作提供了额外的动力。它们似乎存在于马耳他高原上数十平方公里的范围内，从海底以下约 1 m 处开始形成数米厚的层。事实上，地质过程的考虑表明，鹅卵石在中到外大陆架环境中可能比缺乏测量所表明的更常见。对北极大陆架环境的兴趣增加，预计鹅卵石和鹅卵石将普遍存在，为这项工作提供了额外的动力。它们似乎存在于马耳他高原上数十平方公里的范围内，从海底以下约 1 m 处开始形成数米厚的层。事实上，地质过程的考虑表明，鹅卵石在中到外大陆架环境中可能比缺乏测量所表明的更常见。对北极大陆架环境的兴趣增加，预计鹅卵石和鹅卵石将普遍存在，为这项工作提供了额外的动力。