(Table 1) Interstitial water chemistry at DSDP Leg 78A Holes@en

Studies of interstitial water carried out during Deep Sea Drilling Project Leg 78A (Sites 541, 542, and 543) have revealed that alteration of volcanic material dispersed in the sediments is largely responsible for increased concentrations of dissolved calcium and decreased concentrations of dissolved magnesium and potassium. This conclusion is supported by studies of the 87Sr/86Sr ratio of dissolved strontium, as well as by studies of the oxygen isotopic composition of interstitial waters. At Site 543 a large part of the d18O decrease in the interstitial waters must result from diffusive exchange with underlying basement rocks. Data from studies of interstitial water do not indicate upward advection of fluids at Sites 541 and 542.针对深海钻探计划（Deep Sea Drilling Project）第78A航次（站位541、542与543）开展的间隙水研究表明，沉积物中分散的火山物质蚀变，是造成溶解态钙浓度升高、溶解态镁与钾浓度降低的核心诱因。该结论得到了溶解态锶的87Sr/86Sr比值分析，以及间隙水氧同位素组成研究的支撑。在站位543处，间隙水的δ18O大幅下降，其主要成因应为与下伏基底岩的扩散交换作用。间隙水研究数据并未显示站位541与542存在流体向上平流现象。