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Research about Lyon County, Nevada

Source-linked reports with geographic coverage including Lyon County, Nevada.

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Stochastic inversion of gravity, magnetic, tracer, lithology, and fault data for geologically realistic structural models: Patua Geothermal Field case study

Financial risk due to geological uncertainty is a major barrier for geothermal development. Production from a geothermal well depends on the unknown location of subsurface geological structures, such as faults that contain hydrothermal fluids. Traditionally, geoscientists collect many different datasets, interpret the datasets manually, and create a single model estimating faults' locations. This method, however, does not provide information about the uncertainty regarding the location of faults and often does not fully respect all observed datasets. Previous researchers investigated the use of stochastic inversion schemes for addressing geological uncertainty, but often at the expense of geologic realism. In this paper, we present algorithms and open-source code to stochastically invert five typical datasets for creating geologically realistic structural models. Using a case study with real data from the Patua Geothermal Field, we show that these inversion algorithms are successful in finding an ensemble of structural models that are geologically realistic and match the observed data sufficiently. Geoscientists can use this ensemble of models to optimize reservoir management decisions given structural uncertainty.

Nevada

Uranium in the East Walker River Area, Lyon County, Nevada

Uraniferous quartz veins and deposits of other types occur in an area at least six miles long and three miles wide, along the East Walker River in Lyon County, Nevada. Most of the deposits are on the west side of the river. Six properties of areas were mapped, sampled, and tested radiometrically. These properties are: the Far West Willys group, North-west Willys group, West Willys group, Silver Pick property, Grant View hot springs, and the Boerlin ranch radioactive area. The East Walker River area is underlain by coarse-grained porphyritic granite. Cutting the granite are numerous aplite dikes and a few perthite-quartz pegmatites. Faulting was noted in a few places. Radioactive material has been found in the East Walker River area in deposits of four types: (1) quartz veins carrying small amounts of copper, lead, and silver minerals; (2) partly altered granite adjacent to quartz veins; (3) gouge zones, and (4) hot springs. The quartz vein deposits are the most abundant. The uranium minerals pitchblende and kasolite occur in the quartz veins, in aggregates and streaks associated with copper and silver minerals, galena, and barite. In many quartz veins abnormal radioactivity is absent or only locally present. Samples collected from quartz veins contained from 0.001 to 0.14 percent uranium; only five of 46 samples contained over 0.025 percent uranium. Partially altered granite adjacent to the quartz veins in the West Willys No. 7 property contains scattered torbernite, but the highest uranium content noted in deposits of this type was 0.006 percent. The third type of deposit is represented on the Silver Pick property, where a gouge zone of differing thickness contains scattered flakes of torbernite. Five samples from this deposit contained from 0.00.5 to 0.013 percent uranium. The Grant View hot spring is moderately radioactive near the point where it issues from the hillside. Laboratory analysis of both water and sand from this deposit shows little uranium content (0.02 parts per million), and little radioactivity, indicating that the radioactivity is due to some short-lived daughter product, probably radon . The uraniferous material found to date in the area is of too low a grade and small a size to be of present value.

Nevada