Collaborative Research: Long Term Continuous Sampling of Fluids in Instrumented Boreholes on the Eastern Flank of the Juan de Fuca Ridge

建议的合作项目包括在1999年对JOIDES决议在1996年大洋钻探计划第168航次期间在胡安·德富卡海脊东侧钻孔中部署的四个渗透取样器进行回收。此外，还将在钻孔底部收集升体积的样本，并测量钻孔流体温度。这些孔用ODP软木塞密封，ODP软木塞允许通过端口和接口将仪器检索和数据读出到其顶面上的仪器串。 回收涉及使用“阿尔文”号潜水器和一个电缆重返工具（WRT），为期五天，该提议将为进一步开发该工具提供资金。 在取回之后，将对代表三年来钻孔流体成分连续记录的OsmoSampler样品进行大量的主、次和微量元素分析，包括Na、K、Li、Rb、Sr、Si、B、Ba、Mn、Fe、Br、F、NH 4、NO 3、PO 4、SO 4和稀土元素。还将分析它们的各种同位素组成，包括H、O、Sr、B、Li、Cl和Be。将分析大体积样品的氚（以检查周围海水对钻孔流体的污染）、Ar、CO2、CH4浓度、He同位素组成以及C同位素（如果存在足够的CO2和CH4）。 在收回后，将对软木中的孔进行封盖，并在一个孔（1026号现场）处安放新的仪器“帽”，以评价对局部水文变化的化学反应，其中超压基底流体目前正在排出。 这一项目将是迄今为止获得在洋壳内循环的实际地层流体的最佳机会。 这些样品将允许一个基本的检查发生在结晶洋壳的年龄变化过程中，提供了一种手段来测试海洋基底和海水之间的化学通量的模型至关重要，以了解两者的组成。 ***

OCE 98-11557 Kastner OCE 98-12121 Wheat The recommended Collaborative project involves retrieval in 1999 of four OsmoSamplers deployed by the JOIDES Resolution in holes drilled in 1996 on the eastern flank of the Juan de Fuca Ridge during ODP Leg 168. In addition, liter-volume samples will be collected at the base of the boreholes, and borehole fluid temperature measurements will also be made. These holes were sealed with the ODP CORKs, which allow instrument retrieval and data readout through ports and interfaces to instrument strings on their top surface. Retrieval involves five days of use of the Alvin submersible in association with a Wireline Re-entry Tool (WRT), further development of which will be funded by this proposal. After retrieval, the OsmoSampler samples, representing a continuous record of borehole fluid composition for three years, will be analyzed for a large range of major, minor and trace elements, including Na, K, Li, Rb, Sr, Si, B, Ba, Mn, Fe, Br, F, NH4, NO3, PO4, SO4, and the rare earth elements. They will also be analyzed for a wide range of isotopic compositions, including those of H, O, Sr, B, Li, Cl, and Be. The large volume samples will be analyzed for tritium (to check for borehole fluid contamination with ambient seawater), Ar, Xe, CO2, and CH4 concentrations, for He isotopic composition, and for C isotopes if enough CO2 and CH4 are present. The holes in the CORK will be capped after retrieval, with emplacement of a new instrument "cap" at one hole (Site 1026) for evaluation of the chemical response to local hydrographic changes where over-pressured basement fluids are currently venting. This project will represent the best opportunity to date to obtain actual formation fluids that are circulating within the oceanic crust. These samples will allow a fundamental examination of alteration processes occurring within the crystalline oceanic crust as it ages, providing a means for testing models of chemical flux between oceanic basement and seawater essential t owards understanding the composition of both. ***