Statistical grain size parameter of surface samples from Kiel Bay

Geological observations, using "free-diving" techniques (Figure I) were made in September, 1960 and March 1961 along two continuous profiles in the outer Kiel Harbor, Germany and at several other spot locations in the Western Baltic Sea. A distinct terrace, cut in Pleistocene glacial till, was found that was covered with varying amounts and types of recent deposits. Hand samples were taken of the sea-floor sediments and grainsize distribution determined for both the sediment as a whole and for its heavy mineral fraction. From the Laboratory and Field observations it was possible to recognize two distinct types of sand; Type I, Sand resulting from transportation over a long period of time and distance and Type 11, Sand resulting from little transportation and found today near to xvhere it was formed.
Several criterea related to the agent of movement could be used to classify the nature of the sediment; (1) undisturbed (the sediment Cover of the Pleistocene Terrace is essentially undisturbed), (2) mixed by organisms, (3) transported by water movements (sediment found with ripple marks, etc., and (4) "Scoured" (the movement of individual particles of sediment from around larger boulders causes a slow downward movement or "Creeping" which is due to both the force of gravity and bottom currents. These observations and laboratory studies are discussed concerning their relationship to the formation of residual sediments, the direction of sand transportation, and the intensive erosion on the outer edge of the wave-cut platform found in this part of the Baltic Sea.

1960年9月与1961年3月，研究团队采用“自由潜水”观测技术（图1），沿德国外基尔港的两条连续剖面，以及西波罗的海的多处点位开展了地质观测。本次观测发现一处发育于更新世冰碛物（Pleistocene glacial till）中的清晰阶地，其上覆盖着厚度与类型各异的现代沉积物。研究人员采集了海底沉积物手剥样品，并对沉积物整体及其重矿物组分（heavy mineral fraction）分别开展了粒度分布测试。结合野外与实验室观测结果，可将砂体分为两类截然不同的类型：I型砂为经长期、长距离搬运形成的砂，II型砂为搬运作用极弱、形成后就近留存的砂。可通过多项与搬运营力相关的判别准则对沉积物性质进行分类：(1) 未受扰动（该更新世阶地的沉积物覆盖层基本保持原始状态）；(2) 被生物扰动混合；(3) 经水体动力搬运（可见沉积物发育波痕等构造）；(4) “冲蚀”作用（大石块周边的沉积物颗粒发生位移，在重力与底流共同作用下形成缓慢向下的蠕移现象）。本文将对上述观测与实验室研究结果展开讨论，分析其与残余沉积物（residual sediments）形成、砂体搬运方向，以及该波罗的海区域浪蚀台地（wave-cut platform）外缘强烈侵蚀作用之间的关联。