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Full-Text Articles in Geophysics and Seismology
Using Shallow Electromagnetic And Magnetic Techniques To Map Soil Texture And Characterize Salinity And Water Dynamics Below Pecan Orchards, El Paso County, Texas, Kristina Sasser
Open Access Theses & Dissertations
Non-invasive, near surface geophysical tools provide a time efficient and cost-effective approach to study the shallow subsurface. Electromagnetic induction (EMI) instruments are a category of these near surface methods that provide spatial and temporal information (2-D to 4-D) about shallow (<6 m) subsurface properties, from which soil salinity, clay content, and water content can be estimated. However, deconstructing soil apparent electrical conductivity (ECa) from EMI methods into its component parts remains a challenge. This research uses EMI and magnetic geophysical techniques to: (1) compare and contrast the distribution and behavior of ECa, both spatially and temporally, at two flood irrigated agricultural sites (pecan orchards) with different soil layers, properties, and controls on electrical conductivities that lie within the same floodplain in far west Texas; and (2) develop a one-dimensional inversion model using ECa and soil texture data at specified layers from established sites of known high and low ECa to determine soil layer resistivities at various dates during the irrigation season. Data are compared to soil sensor bulk EC and volumetric water content data at corresponding depths to validate results. Soils at both sites exhibit large ECa contributions from textural controls, and irrigation frequency. The combination of these two controls dictate where and how quickly secondary minerals precipitate, clog soil pores, reduce infiltration, and salinize the groundwater. Insight from this research aids in ongoing efforts to characterize vadose zone hydrology in dryland critical zones with high infiltration and serves as a guide for locations where future soil sampling will occur.
Geophysical Model Of The Cu-Mo Porphyry Ore Deposit At Copper Flat Mine, Hillsboro, Sierra County, New Mexico, Adrian Emmanuel Gutierrez
Geophysical Model Of The Cu-Mo Porphyry Ore Deposit At Copper Flat Mine, Hillsboro, Sierra County, New Mexico, Adrian Emmanuel Gutierrez
Open Access Theses & Dissertations
A 3D gravity model of the Copper Flat Mine was performed as part of the exploration of new resources in at the mine. The project is located in the Las Animas Mining District in Sierra County, New Mexico. The mine has been producing ore since 1877 and is currently owned by the New Mexico Copper Corporation, which plans o bringing the closed copper mine back into production with innovation and a sustainable approach to mining development. The Project is located on the Eastern side of the Arizona-Sonora-New Mexico porphyry copper Belt of Cretaceous age. Copper Flat is predominantly a Cretaceous …
Software Development For A Three-Dimensional Gravity Inversion And Application To Study Of The Border Ranges Fault System, South-Central Alaska, Rolando Cardenas
Software Development For A Three-Dimensional Gravity Inversion And Application To Study Of The Border Ranges Fault System, South-Central Alaska, Rolando Cardenas
Open Access Theses & Dissertations
The Border Ranges Fault System (BRFS) bounds the Cook Inlet and Susitna Basins, an important petroleum province within south-central Alaska. A primary goal in the research is to test several plausible models of structure along the Border Ranges Fault System using a novel three-dimensional inversion utilizing gravity and magnetic data, constrained with other geophysical, borehole and surface geological information. This research involves the development of inversion modeling software using a Borland C++ compiler as part of the Rapid Application Development (RAD) Studio. The novel inversion approach directly models known geology, and "a priori" uncertainties on the geologic model to allow …