Stable Isotope Geochemistry of Quartz, Clay Minerals and Zeolites Under Sedimentary/Diagenetic/Low Grade Metamorphic Conditions

需要关于沉积/成岩/低级变质硅酸盐矿物(石英、粘土和沸石)氧同位素行为的基本数据。这项研究包括对石英和沸石的矿泉水-水氧同位素分馏进行校准，以及对粘土的晶内同位素分馏进行校准。它还包括沸石的氧同位素分析技术和沸石与水之间的同位素交换动力学的研究。石英-水氧同位素分馏将通过在严格控制的条件下在水溶液中生长石英晶体在大约0、25、50和75摄氏度进行校准。结合公布的200摄氏度及以上的分馏数据，这些结果应该会得出可靠的变质温度范围。除了提供有关石英的信息外，这些结果还将有助于我们估计其他矿泉水的同位素分馏。旨在测量和校准粘土中晶体内同位素分馏的研究将基于部分氟化和热脱羟基。这将允许估计粘土形成的温度和粘土形成流体的同位素组成。这样做的能力在砂岩的同位素研究中将特别有用，因为在砂岩中很少遇到同源矿物对。对沸石同位素行为的研究将表明这种常见的成岩/低级变质岩群中各种矿物的同位素组成在多大程度上提供了有关其形成条件的有用信息，并加强了氧同位素技术在了解低温过程中的应用。

Fundamental data on the oxygen isotopic behavior of sedimentary/diagenetic/low-grade metamorphic silicate minerals (quartz, clays and zeolites) are needed. The research includes calibration of mineral-water oxygen isotopic fractionations for quartz and for zeolites and calibration of intracrystalline isotopic fractionations in clays. It also includes research on techniques for the oxygen isotopic analysis of zeolites and on the kinetics of isotopic exchange between zeolites and water. The quartz-water oxygen isotope fractionation will be calibrated at approximately 0, 25, 50 and 75 degrees C by growing quartz crystals in aqueous solution under carefully controlled conditions. The results, when combined with published fractionation data for 200 degrees C and above, should yield reliable metamorphic temperature range. In addition to providing information about quartz, the results will be useful in our attempts to estimate other mineral-water isotopic fractionations. Studies aimed at measuring and calibrating intra-crystalline isotopic fractionations in clays will be based both on partial fluorination and on thermal dehydroxylation. This will permit an estimate of both the temperature of the clay formation and the isotopic composition of the clay-forming fluid. The ability to do this would be especially useful in the isotopic study of sandstones, where cogenetic mineral pairs are very rarely encountered. The proposed studies of the isotopic behavior of zeolites will indicate the degree to which the isotopic compositions of various minerals in this common diagenetic/low-grade-metamorphic group provide useful information about the conditions of their formation and enhance applications of oxygen isotope techniques to the understanding of low temperature processes.