Ten-month observation of the bottom current regime across a sediment drift of the Pacific margin of the Antarctic Peninsula
Ten-month observation of the bottom current regime across a sediment drift of the Pacific margin of the Antarctic Peninsula
复制标题
南极半岛太平洋边缘沉积物漂移区海底流态十个月观测
作者：
A. Camerlenghi;A. Crise;C. Pudsey;E. Accerboni;R. Laterza;M. Rebesco
我们提出了两个时间序列的底部电流和温度收集8米以上的海底上的大型沉积物漂移位于南极半岛的太平洋边缘的大陆隆起的两侧。平均流速相当（分别为6.2 cm s−1和6.1 cm s−1），但平均方向相差约121°。平均流的方向遵循等深线，最大流速从未超过20 cm s−1（低于典型的海底风暴阈值）。电位温度非常稳定（两个位置分别为0.11 ± 0.01°C和0.13 ± 0.02°C）。互协方差表明，一个显着的峰值在20.2天的滞后，略长于18.7天的旅行时间计算的两个站之间的等深线（98.4公里），从而提供证据的地形控制底层水流。所观察到的底层水流是一致的沉积全新世半远洋沉积物的“漂移维护”阶段。在冰川时期的“漂流维持”阶段和较老的“漂流增长”阶段的古海洋学条件的指标目前太少，无法充分了解过去的海洋学条件如何影响漂流的演变。
We present two time series of bottom current and temperature collected 8 m above the seabed on either side of a large sediment drift located on the continental rise of the Pacific margin of the Antarctic Peninsula. The mean current speed is comparable (6.2 cm s−1 and 6.1 cm s−1 respectively), but the mean direction differs by about 121°. The direction of mean flow follows the bathymetric contour, and the maximum speed never exceeds 20 cm s−1 (below the typical benthic storm threshold). The potential temperature is remarkably stable (0.11 ± 0.01°C and 0.13 ± 0.02°C at the two sites). The cross-covariance indicates a significant peak at 20.2 days lag, slightly longer than the travel time of 18.7 days calculated between the two stations following the isobaths (98.4 km) and thus providing evidence for the topographic control on bottom water flow. The observed bottom water flow is consistent with deposition of Holocene hemipelagic sediments of the ‘drift maintenance’ stage. Indicators for palaeoceanographic conditions during glacial periods of the ‘drift maintenance’ stage and the older ‘drift growth’ stage are at present too scarce to understand fully how the past oceanographic conditions influenced the evolution of the drifts.