Late Pleistocene to Holocene marine transgression and thermohaline control on sediment transport in the western Magellanes fjord system of Chile (53°S)
Late Pleistocene to Holocene marine transgression and thermohaline control on sediment transport in the western Magellanes fjord system of Chile (53°S)
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智利西部麦哲伦峡湾系统晚更新世至全新世海侵和温盐对沉积物输送的控制（南纬53°）
DOI：
10.1016/j.quaint.2006.10.043
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发表时间：
2007
影响因子：
2.2
通讯作者：
C. Schneider
中科院分区：
文献类型：
--
作者：
R. Kilian;Ó. Baeza;T. Steinke;M. Arevalo;C. Ríos;C. Schneider
在智利最南端的西部麦哲伦海峡，海侵发生在14,500至13,500 Cal.BP之间。这表明生物碳酸盐的积累强烈增加，并在沉积物记录中首次出现有孔虫。从那时到11500年前，由于较高的盐度和粘土絮凝，以及晚期冰川消退，西部峡湾的沉积成为主要的原地沉积。现今具有广泛代表性的全新世温盐分带模式和沉积速率表明，西风带阻碍了来自冰川区的浅层(0-30m水深)富含粘土的冰川淡水向西流出。在全新世，安第斯山脉的均衡抬升过度补偿了海平面的上升。在冰川负荷较高的地区，这导致峡湾岩床变浅，与海水的交换受到限制，特别是因为大量淡水流入产生了强大的跃层，并保存了峡湾底部的古老咸水。在气候分水岭以东，Seno Skyring峡湾系统显示出常年稳定的层结，尽管在水柱上部30-50米处有强烈的风致东移表层流。这样的洋流使得冰川粘土在冰河晚期大量向东迁移。该地区的沉积物岩心表明，全新世期间，从东向东的沉积物通量减缓，可能是由于强度较小的西风。研究了横跨南安第斯山脉过湿气候分水岭的峡湾系统的现今温盐特征，表明海洋和淡水之间的交换的细节，这是评估该地区沉积物输送途径、生物生产力和解释古气候记录的基础。
In the Western Strait of Magellan in southernmost Chile marine transgression occurred between 14,500 and 13,500cal.BP. This is indicated by strongly increased accumulation of biogenic carbonate and first appearance of foraminifers in sediment records. From that time until 11,500cal.BP, sedimentation in the western fjords became predominant autochthonous, due to higher salinity and clay flocculation, and Late Glacial glacier retreat. Present day thermohaline zonation pattern, extensively representative for the Holocene, and sedimentation rates indicate that westerlies hampered westward outflow of superficial (0–30m water depth) glacial clay-rich freshwater from glaciated areas. During the Holocene, isostatic uplift of the Andes overcompensated sea level rise. In areas with high Glacial glacier loading this led to shallowing fjord sills and restricted exchange with marine water, especially since high freshwater inflow produced strong pycnoclines and preserved old saline water in fjord bottoms. To the east of the climate divide the Seno Skyring fjord system shows a year-round stable stratification, despite a strong wind-induced eastward superficial current in the upper 30–50m of the water column. Such currents enabled significant Late Glacial eastward transport of glacial clay. Sediment cores from this area indicate that east-ward sediment flux slowed down during the Holocene, probably due to less intense westerlies. Investigated present day thermohaline characteristics of the fjord system across the superhumid climate divide of the Southern Andes indicate details of the exchange between marine and freshwater which are fundamental for evaluation of sediment transport pathways, biogenic productivity and interpretation of paleoclimate records in this area.
影响因子：
56.9
作者：
Lamy, F;Kaiser, J;Stoner, J
通讯作者：
Stoner, J