EXPERIMENTAL AND NUMERICAL STUDY OF WATER ROCK INTERACTIONS USING DIFFERENT TYPES OF ROCKS FROM SOUTHERN NEVADA

Leaching experiments using three types of rocks (dolomite, limestone, and felsic volcanic rocks) from southern Nevada and super pure water of various pH values were conducted in the laboratory. The leachates obtained from these experiments were analyzed for the concentrations of major solutes and trace elements. The sorption behavior and geochemical characteristics of trace elements in groundwater were also investigated based on studies reported in literature and our studies. The concentrations of trace elements in the leachates were normalized to chondrite and the corresponding local rocks to assess how various factors affect the water rock interactions. The distribution coefficients (Kd) used in transport modeling were determined either based on the leaching experiments or on the literature values. Trace element transport from Yucca Flat to the Amargosa Desert in southern Nevada was simulated. The rain-induced recharge from the Spring Mountains was used to drive the flow simulation. Six scenarios were assumed and modeled to evaluate the geochemical signatures of the possible flow paths from Yucca Flat to the Amargosa Desert. The relative likelihood of the flow paths was ranked for the study area based on criteria of fitness to the actual conditions.