Geochemistry of rocks, precipitation, and water sources from Pinnacles National Park, California, 2016-2017

Ephemeral springs and other groundwater sources in Pinnacles National Park (San Benito and Monterey Counties, CA) were sample in the Spring and Fall of 2015-2017 during several field visits. Field parameters such as in-situ pH, TDS/conductivity, and temperature were assessed. GPS coordinates for all samples were taken. Comprehensive water chemistry, including major and minor elements, alkalinity, nutrients (and other parameters), Sr isotopes and REE concentrations, was analyzed at the National Water Quality Lab, USGS, Denver CO; and at the USGS in Menlo Park, CA. Tritium was analyzed by the Menlo Park Tritium Lab. One field visit in summer 2017 was made to obtain rock samples from the volcanic and sedimentary rocks in and around the park, which were digested and analyzed for whole rock chemistry (XRF, OES, ICP MS) by the Analytical Chemistry Lab (Mineral Resources Program, USGS, Denver CO) and Sr isotopes and minor element and REE geochemistry in Menlo Park labs.

2015-2017年的春季与秋季，科研团队通过多次野外考察，对美国加利福尼亚州圣贝尼托县与蒙特雷县境内的尖顶国家公园（Pinnacles National Park）内的暂时性泉及其他地下水源开展了采样工作；现场测定了原位pH值、总溶解固体（TDS）与电导率以及水温等野外参数，并采集了所有采样点位的GPS坐标。包括常量与微量化学组分、碱度、营养盐及其他相关参数、锶（Sr）同位素与稀土元素（REE）浓度在内的综合水化学指标，分别由美国地质调查局（USGS）丹佛分中心国家水质实验室，以及加利福尼亚州门洛帕克的USGS实验室完成分析；氚（Tritium）样品由门洛帕克氚实验室开展检测。2017年夏季开展了一次野外考察，采集公园及周边区域的火山岩与沉积岩样品，上述样品经消解处理后，由美国地质调查局丹佛分中心矿产资源项目组的分析化学实验室完成全岩化学分析（采用X射线荧光光谱法（XRF）、发射光谱法（OES）、电感耦合等离子体质谱法（ICP-MS）），并由门洛帕克的实验室完成锶同位素、微量组分及稀土元素地球化学分析。