Halogen geochemistry of the McMurdo dry valleys lakes, Antarctica: Clues to the origin of solutes and lake evolution
Halogen geochemistry of the McMurdo dry valleys lakes, Antarctica: Clues to the origin of solutes and lake evolution
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DOI：
10.1016/j.gca.2004.06.040
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发表时间：
2005-01-15
影响因子：
5
通讯作者：
Poreda, RJ
中科院分区：
文献类型：
--
作者：
Lyons, WB;Welch, KA;Poreda, RJ
我们已经测定了南极泰勒谷冰湖中卤素和硼的浓度，以便更好地确定盐的来源和这些不寻常水体的进化历史。此外，我们报告了一系列的I-129测量结果，这些测量结果与之前的Cl-36数据进行了比较，这些数据也有助于限制溶质的来源和湖泊的历史。将这些新数据与过去四十年来对这些系统的研究结合起来，我们可以得出以下结论。霍尔湖是最年轻的湖泊，其溶质的主要来源是海洋气溶胶和风成盐的溶解，以及冰川上灰尘的化学风化作用。Fryxell湖是一个微咸水湖泊，其地球化学特征主要是沉积物-水界面处盐饱和盐水的扩散和近期冰川融水的填充。这些水域有化学风化和海洋气溶胶成分。邦尼湖有两个不同的裂片，它们的高盐低钾有不同的化学成分。这两个裂片都是古代海水的残余物，它们被风化产物的输入所改变。当溶质通过矿物沉淀失去时，这个湖也被低温浓度的时期所改变。因此，邦尼湖不同寻常的地球化学在一定程度上要归功于泰勒谷至少在过去300年里的气候变化。来自泰勒谷的I-129数据与来自北半球结晶岩石裂缝流体的数据相似。版权所有(C) 2005 Elsevier Ltd
We have determined the halogen and boron concentrations in the ice-covered lakes of Taylor Valley, Antarctica, to better establish the sources of salts and evolutionary histories of these unusual water bodies. In addition, we report on a series of I-129 measurements that were compared with previous Cl-36 data that also help constrain the source of solutes and histories of the lakes. The new data, when put into context of previous work on these systems over the past forty years, allow us to make the following conclusions. The primary source of solutes to Lake Hoare, the youngest of the lakes, is the dissolution of marine aerosols and aeolian salts and the chemical weathering of dust on the glaciers. The geochemistry of Lake Fryxell, the brackish water lake, is primarily dominated by the diffusion from a halite-saturated brine at the sediment-water interface and the recent infilling of the lake by glacier meltwater. These waters have chemical weathering and marine aerosols components. Lake Bonney has two distinct lobes whose hypersaline hypolimnia have different chemistries. Both of the lobes are remnants of ancient marine waters that have been modified by the input of weathering products. This lake has also been modified by periods of cryogenic concentration when solutes have been lost via mineral precipitation. Thus the geochemistry of Lake Bonney owes its unusual geochemistry, in part, to variations in the climate in the Taylor Valley over at least the past 300kyr. The I-129 data from the Taylor Valley are similar to those from fracture fluids in crystalline rocks from the Northern Hemisphere. Copyright (C) 2005 Elsevier Ltd.