Resistivity Probe Deployments at the Endeavour ISS

智力优势：氯离子浓度是控制高温热液化学成分的主要变量。氯化物浓度通过其在确定矿物溶解度中的重要性而影响这种控制。近年来，热液流体中的氯化物浓度主要受相分离的控制。相分离又由热源的性质来控制。近年来，由于岩浆岩壁和喷发事件，热液流体中相分离的性质和程度发生了短期和非常剧烈的时间变化，并由此引起了氯离子浓度的变化。构造裂缝事件也被认为引起温度和氯化物浓度的时间变化。大多数这些事件都是通过不频繁的船上采样工作观察和记录的，事件的时间性质定义不清。我们开发了一种能够测量温度和流体电阻率的原位仪器，作为氯化物浓度的代表。到目前为止，该仪器已在两个RIDGE 2000计划综合研究地点（奋进号和9ºN）部署了几个月，取得了良好的效果。这些数据记录表明氯化物浓度在时间尺度上的短期变化是出乎意料的，也是我们以前没有能力观察到的。在这个项目中，我们将在奋进号地震数据集的背景下评估现有的温度和喷口流体电阻率数据集。在该项目的支持下，我们将在High Rise火山口部署这些仪器，以增强将通过连接到NEPTUNE加拿大光纤电缆的仪器在Main奋进号和Mothra火山口收集的数据。更广泛的影响：当我们转向试图更好地理解热液系统和海洋学中工作过程的时间性质时，原位传感器变得越来越重要。在开发能够在热液喷口恶劣环境中工作的传感器期间获得的见解可能在许多领域有用，特别是在热液环境中开发海底观测站的努力将大大有助于该传感器的成功继续部署。

Intellectual Merit: The concentration of chloride ion is a master variable in controlling the chemical composition of high temperature hydrothermal fluids. Chloride concentration affects this control via its importance in determining mineral solubility. It has become apparent in recent years that the chloride concentration in hydrothermal fluids is controlled primarily by phase separation. Phase separation is, in turn controlled by the nature of the heat source. Short term and very dramatic temporal changes in the nature and degree of phase separation and the resultant changes in chloride concentration in hydrothermal fluids as a result of magmatic diking and eruptive events have been observed in recent years. Tectonic cracking events have also been seen to cause temporal changes in both temperature and chloride concentration. Most of these events have been observed and documented by infrequent ship-based sampling efforts and the temporal nature of the events is poorly defined. We have developed an in-situ instrument that is capable of measuring temperature and fluid resistivity as a proxy for chloride concentration. This instrument has so far been deployed at two RIDGE 2000 Program Integrated Study Sites (Endeavour and 9ºN) for periods of several months, with excellent results. These data records indicate short term changes in chloride concentration on a temporal scale which was unexpected and that we have not had the ability to observe previously. In this project we will evaluate existing data sets of temperature and vent fluid resistivity in the context of the Endeavour seismic data set. Under support of this project, we will deploy these instruments at the High Rise vent field to augment data that will be collected at the Main Endeavour and Mothra vent fields by instruments connected to the NEPTUNE Canada fiber optic cable.Broader Impacts: In-situ sensors are becoming increasingly important as we shift toward trying to better understand the temporal nature of processes working in hydrothermal systems as well as oceanography in general. The insights gained during the development of sensors capable of operating in the hostile environment of hydrothermal vents is likely to be useful in many fields, in particular the efforts to develop seafloor observatories in hydrothermal environments will be greatly aided by the successful continued deployment of this sensor.