Fluid Inclusions in Halite: Clues to the History of Seawater

拟议的研究计划旨在提高我们对过去600英里内海水化学演化的理解。关于地球历史的。为了实现这一目标，我们计划扩展我们的分析数据库，用于分析海洋蒸发岩中捕获在盐岩(氯化钠)中的流体包裹体中的卤水的化学成分。这些卤水中的许多都是盐析出的溶液的样本。在海洋蒸发岩中，这些卤水主要或全部来自海水；因此，它们的组成反映了盐析出时海水的组成。在许多情况下，这些卤水从海水中演化得如此复杂，以至于从包裹体流体的组成中几乎无法获得有关母海水成分的信息。幸运的是，一些海洋蒸发岩中卤水的演化已经足够简单，因此可以重建起始海水的大部分化学成分。到目前为止积累的数据表明，在过去的600英里内，海水的组成出人意料地保守。目前，这些数据仍不完整。我们建议将其大大扩展，并构建显生界古海水成分的合理完整的记录。

The proposed program of research is designed to improve our understanding of the chemical evolution of seawater during the last 600 m.y. of Earth history. To accomplish this, we plan to extend our analytical data base for the chemical composition of brines in fluid inclusions trapped in halite (NaCl) in marine evaporites. Many of these brines are samples of the solutions from which the salt precipitated. In marine evaporites these brines are largely or entirely derived from seawater; their composition therefore reflects the composition of seawater at the time of salt precipitation. In many instances the evolution of these brines from seawater has been so complicated, that little information regarding the composition of the parent seawater can be gained from the composition of the inclusion fluids. Fortunately, the evolution of the brines in some marine evaporites has been sufficiently simple, so that much of the chemistry of the starting seawater can be reconstructed. The data accumulated to date indicate that the composition of seawater has been surprisingly conservative during the past 600 m.y. At present these data are still fragmentary. We propose to extend them considerably, and to construct a reasonably complete record of the composition of seawater during the Phanerozoic Eon.