• CONTROLLED SOURCE AUDIO MAGNETO- TELLURIC (CSAMT) GEOPHYSICAL INVESTIGATION OF THE MIDDLE SAN PEDRO RIVER BASIN, SOUTHEASTERN ARIZONA

      ANDERSON, KATHERINE E.; EDGE, RUSSELL D.; HACKSTON, ABIGAIL J.; MARAJ, SHOBA; ROMANOWSKI, MICHAL J.; SEAMONS, REED L.; Sternberg, Ben K.; STOKES, PHILIP J.; THURNER, SALLY M.; University of Arizona (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 2008-05-14)
      Groundwater resources are essential to support the growing population of Benson as well as the agriculture, and wildlife throughout the Middle San Pedro Basin. A refined model of the hydrogeologic framework within the region is necessary to allow for the most efficient allocation of the area’s ground water resources by city planners and water managers in charge of future development. New data were collected by the University of Arizona’s Geophysics Field Camp to update and improve this representation. This survey utilizes Controlled Source Audio Magnetotellurics (CSAMT) to characterize previously unstudied locations in the San Pedro Basin. CSAMT data were processed and interpreted using software from Zonge Engineering and Interpex Ltd. Seven receiver stations along a five-kilometer Middle San Pedro transect were used to determine the resistivities of several basin-fill units. Results show some resistivity variability with respect to depth among the sampled regions. In the simplest representation of the data, four layers were modeled. Resistivities ranged from 15-30 ohm-m in the near-surface units. Deeper units showed resistivities of 5-10 ohm-m. These results were plotted to help identify conductive aquitard (clay) and potentially more resistive aquifer units. This clay unit could correspond to a thin unit of the St. David Formation, which has previously been identified as a confining unit between two separate basin aquifers. CSAMT data indicate that the local bedrock is deeper than 500 m.
    • Controlled Source Audio Magnetotelluric (CSAMT) Surveys in the Tucson Mountains

      Fleming, John B.; Hafit, Husna D.; Khalid, Khaliza B.; Martinez, Jesse G.; Powell, Jonathan A.; Ren, Xin; Ridzuwan, Mohamad; Sternberg, Ben K.; University of Arizona (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 2012-05-15)
      Controlled Source Audio-Magnetotellurics (CSAMT) surveys were conducted in 2012 in the Tucson Mountains as a continuation of the 2010 and 2011 Laboratory for Advanced Subsurface Imaging (LASI) field studies in this area. This geologic setting was chosen for its high-resistivity impermeable volcanic layer overlaying porous sedimentary layers. This type of structure has potential for water resources and as a reservoir for compressed air energy storage (CAES). The data from 2,500 meters of CSAMT survey lines generated 900 meter-deep resistivity versus elevation cross-sections and six plan maps of the depth and elevation to the buried conductive layer. Our results are generally in agreement with the geologic cross sections developed by Lipman (1993) and previous TEM data that confirmed the presence of a deep conductive layer beneath a resistive volcanic sequence.
    • GEOPHYSICAL INVESTIGATION OF SUBSIDENCE FISSURES NEAR WILLCOX, ARIZONA

      Barbato, Nicholas A.; Bingham, Peter D.; Conley, Michael C.; DeFilippo, Makko A.; Desser, Elizabeth M.; King, Christina A.; Lewis, Benjamin J.; McCarthy, Emily S.; Mendoza, Nirio; Rucker, Michael L.; et al. (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 2009-05-14)
      An interdisciplinary survey consisting of four geophysical methods was conducted on the western edge of the Apache Generating Station’s property in Willcox, Arizona. The aim of the survey was to apply various methods for the detection of earth fissures and desiccation cracks. The geophysical methods used were static magnetic field measurements, frequency domain electromagnetics (FEM), ground penetrating radar (GPR), and seismic. Two grids were delineated and surveyed by each method. Grid 1 was set up at a site containing a fissure with visible surface expression over some parts of the grid, and Grid 2 was set up at a site with little visible surface expression of the fissure, but was suspected to contain a fissure in the subsurface. At another location, northwest of the Apache Generating Station, three lines were surveyed in an area of known desiccation cracks. All of the methods showed an anomaly associated with the fissure in Grid 1. Furthermore, at locations where the fissure is not visible in Grid 1, there were still strong anomalies in line with the suspected location of the fissure extending below the surface. Magnetic data from Grid 2 suggests that magnetics may not be a useful method in subsurface earth fissure detection at this site, where we believe that the fissure is only a very small crack with small aperture at depth. The electromagnetic results from Grid 2 show anomalies extending from lines 1 through 5 where there is only minimal surface expression in lines 1 and 2 and no surface expression in lines 3-5. No anomaly was seen in the northern end of Grid 2. It was found that GPR in Grid 2 did not display conclusive results in distinguishing subsurface earth fissure anomalies from other anomalies, such as roots. Seismic lines in Grid 2 show anomalies in the profiles that could indicate the presence of earth fissures; however a thin high velocity horizon may appear as a subsurface fissure, and this made interpretations more challenging. At the desiccation crack site, there is evidence of a shallow feature, which we interpret to be a dessication crack and not an earth fissure. A dirt road was present at the desiccation crack site, and it is possible that the road may have produced some of the observed anomalies due to rain-water channeling effects. The locations of fissures were confirmed by trenches excavated at the locations where anomalies were visible in the geophysical data, but where the fissures were not exposed at the surface.
    • GEOPHYSICAL INVESTIGATION OF THE TUCSON MOUNTAINS

      Avanesians, Patrick; Daroch, Giancarlo A.; Fleming, John; Hundt, Stephen A.; Leake, Steven C.; Ojha, Lujendra; Sternberg, Ben K.; Wampler, David F.; University of Arizona (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 2011-05-14)
      Transient Electromagnetic (TEM), Controlled Source Audio Magnetotellurics (CSAMT), Gravity, and Magnetic data were collected in the Tucson Mountains during the Spring semester, 2011. The goal was to investigate the extent of a low-resistivity porous sedimentary layer and faults that may form potential traps located under the surface volcanic layers, as interpreted by Lipman 1993. The sedimentary layer under the volcanics has the potential to be used for either water resources or compressed air storage to store solar energy. The results from the TEM and CSAMT surveys broadly correlated with the thickness of the volcanic layer and throw of the faults interpreted by Lipman, 1993. The gravity modeling suggested the faults may have a larger throw than what was indicated by the other methods. Because of the fundamental uncertainty in the densities to use in the modeling, it was concluded that the gravity modeling may not give as accurate a prediction of the structure in this region. For further investigation of the deep porous sedimentary layer, we suggest that TEM and CSAMT are the most effective methods.
    • GEOPHYSICAL INVESTIGATIONS IN THE UPPER SAN PEDRO RIVER BASIN, BENSON, ARIZONA

      Aspiras, Gerald P.; Crawford, Matthew T.; Cylwik, Scott D.; Dangi, Tarun; Dewan, Milan M.; Hays, Naydene R.; Miller, Thomas E.; Sternberg, Ben K.; Thompson, Mayo; University of Arizona (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 2006-05-07)
      Four geophysical surveys were conducted at the Nature Conservancy about 20 miles north of Benson, AZ, in the Upper San Pedro River Basin, in order to better understand the nature of the sub-surface features of the basin. The geophysical methods included TEM (Transient Electromagnetic), seismic, EM34 and magnetic surveys. The TEM, seismic and magnetic surveys were conducted perpendicular to the river basin while the EM34 lines followed the riverbed. The perpendicular surveys were divided into two regions, referred to as the South and North Lines. The TEM, seismic, and magnetic surveys revealed a consolidated bedrock structure at shallow depths (30-40 m) along the South Line. The feature has an east-west extension of approximately 500 meters, and is located just east of the San Pedro River. None of the perpendicular surveys were able to detect bedrock features along the North Line, implying that the depth to bedrock exceeds the maximum depth of this investigation (360 m). Both lines showed regions of high porosity, and, potentially, of saturated materials. These regions were more prevalent along the North Line, where numerous highly porous areas were detected at various depths (including one region beginning at a depth of 50 meters and extending at least to 360 m). The EM34 failed to detect any appreciable long-wavelength changes in conductivity along the riverbed, though localized point anomalies were found.
    • Geophysical Investigations near Yuma, Arizona

      Al-Zaabi, Mohamed; Eastman, Julie; Huebner, Laura; Muhlenkamp, Brianna; Riley, Jeannemarie; Rohe, Chris; Smith, Gwynneth; Souza, Deborah; Sternberg, Ben; Taft, Cristin M.; et al. (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 2005)
      VLF (Very Low Frequency), magnetic, TEM (Transient ElectroMagnetics), and Seismic were performed in Yuma, Arizona over two weekends in February and March of 2005. The targets of interest in Yuma included the depth to the shallow bedrock, the trace of the Algodones Fault, and the distribution and thickness of clay units. The VLF and magnetic surveys both proved not to be valuable for the interpretation of groundwater or bedrock depth. The Seismic surveys found a quartz monzonite horst structure at a depth of 8 meters and 250 in length and a graben at 8 meters depth and 48 meters in length. The TEM surveys were performed along Line 2 and Line 4 for Site One, Line 1 and Line 3 for Site Two, and SG1 line and SG2 line for Site Three. The TEM survey, located near the Seismic surveys, was in agreement with the findings of these Seismic surveys. At all sites, the TEM surveys were useful for determining depth to water table. At one site, the TEM survey mapped substantial near-surface clay layers.
    • GEOPHYSICAL SURVEYS AT THE AVRA-VALLEY TEST SITE AND CIENEGA CREEK

      Sternberg, Ben K.; Al-mujaini, Ali A.; Ashley, Darin W.; Birken, Ralf; Crawley, Sean E.; Dean, Rayner W.; Glaccum, Matthew B.; Haack, Jerry M.; Hardin, Ernest L.; LaFiame, Lisa M.; et al. (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 1993-06-23)
    • GEOPHYSICAL SURVEYS AT THE UNITED MUSICAL INSTRUMENTS, SUPER-FUND SITE, NOGALES, ARIZONA

      Bishop, Bradley P.; Casto, Daniel W.; Chama, Mukonde; Heinecke, Justin M.; Henley, Michael L.; Malsom, Andrew A.; Mason, Mark S.; Miller, Alisa C.; Mwewa, David C.; Potts, K. Greg; et al. (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 2000-05-07)
      During the Spring semester, 2000, the University of Arizona Geophysics Field Camp (GEN/GEOS 416/516 class) conducted geophysical surveys in the vicinity of the United Musical Instruments facility near Nogales, Arizona. This site is a super-fund site, due to the presence of contaminants, including TCE, in the ground water. The contaminants are presumed to have come from cleaning and electroplating solutions, which had been dumped into a small pond on the UMI property. The U.S. Geological Survey provided the funding for our study. The objective was to determine subsurface structural information that would help interpret possible future movement of the contaminant plume. Transient electromagnetic (TEM) data were most useful for interpreting the subsurface geohydrology. Water table was found at a depth of approximately 30 meters, north of the UMI building. A particularly interesting feature in the TEM data was a high-resistivity anomaly and an associated low-resistivity anomaly 10 to 1 00 meters northeast of the UMI building. We interpret the high-resistivity anomaly as possibly being due to an impermeable levee that was associated with a buried stream channel and the low-resisitivity anomaly as possibly being due to the pooling of conductive contaminated fluids against the impermeable levee. DC resistivity surveys were dominated by cultural coupling, which was pervasive m the survey area. Magnetic readings were used to help locate potential cultural interference. Gravity surveys indicated a low-density anomaly, which may be due to a buried stream channel. This feature could be related to the features mapped with the TEM surveys. The seismic survey indicated progressively more compacted and cemented alluvium, overlying the Nogales formation. The seismic data did not provide any direct information about the geohydrology of the area
    • GEOPHYSICAL SURVEYS AT VULCAN MINE

      Bennett, Jesse E.; Bowler, Anthony T.; Cavabaugh, William R.; Glass, Aaron J.; Green, John D.; Katbah, Maher M.; Murphy, George P.; Pepe, Jennifer L.; Poulton, Mary M.; Qin, Jizeng.; et al. (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 1991-03-27)
    • GEOPHYSICAL SURVEYS IN COCHISE COUNTY

      Birken, Ralph A.; Hassouneh, Mohammed H.I.; Heath, Gail; LaBrecque, Douglas J.; Lindsay, David S.; McGraw, Matthew D.; Milton, Stuart L.; Mullarky, Leo J.; Nguyen, Qui P.; Nickerson, Mark D.; et al. (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 1994-06-22)
    • GEOPHYSICAL SURVEYS IN PIMA COUNTY

      Andrews, Joseph N.; Backes, Brian D.; Balay, Scott; Barry, James F.; Birken, Ralf A.; Brown, Marshall P.; Davenport, Michael S.; Debroux, Patrick S.; Dwinnell, Heidi K.; Franklin, Tiffany D.; et al. (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 1995-06-21)
    • Geophysical Surveys in the Blue Nose Mine Area, Patagonia Mountains, Arizona

      Bambi, Osvaldo S. P.; Brock, Ryan K.; Domingos, Elsa D.; Evaristo, Figueiredo C. K.; Gourley, Kenneth C.; Hanna-Wilson, Michael T.; Kilezi, Miguel Alberto; Kuehn, Tyler S.; Li, Echo; Lima, Ivo; et al. (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 2019-05-12)
      The US Geological Survey and the US Forest Service requested an investigation of the sediment and groundwater properties of the Blue Nose Mine in the Patagonia Mountains of southern Arizona to help with future remediation efforts due to historical mining of the area. Information on the depth of the existing tailings piles was also requested to aid in determining the best removal strategy. The surveys carried out in this investigation include direct current (DC) resistivity, transient electromagnetics (TEM), EM-31 and EM-38, total-field magnetism, and petrophysical laboratory analysis. The 20m TEM loop and DC resistivity data revealed low-resistivity regions, less than 10 Ohm-m, surrounded by several-thousand Ohm-m resistive features, indicating a large conductive zone around the existing mine workings. The 10 m TEM loops, as well as the EM-31, and EM-38 data, collected on the tailings piles indicate a conductive layer reaching 8 m in depth from the surface. These help to delineate the conductive tailings material from the surrounding hillside. The total-field magnetic survey was useful in determining several linear features and magnetic trends, including the Harshaw Creek Fault on the eastern edge of the study site. The petrophysical analysis aimed to help refine subsurface interpretations, but due to the small sample size only provides a limited correlation to the DC resistivity and TEM data. Correlations between magnetic and resistive datasets reveal three zones with differing electromagnetic properties, one of which may correlate with the Blue Nose ore deposit.
    • GEOPHYSICAL SURVEYS IN THE COPPER CHIEF MINE AREA

      Buggenhagen, John E.; Clote, Valerie J.; Dixon, Angela M.; Fitzsimmons, Clark D.; Forman, Katherine C.; Gain, Erik R.; Galloway, Brian K.; Green, Rori L.; Hammers, W. Bre; Hurguy, Jr., William; et al. (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 1992-06-22)
    • Geophysical Surveys in the Harshaw Creek Area, Patagonia Mountains, Arizona

      Brown, Kate Willa; Harris, Ryan A.; Russell, Harrison C.; Sternberg, Ben K.; Wang, Zida; Xavier, Dania; University of Arizona (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 2020-08-01)
      Over the weekends of February 15-16 and 22-23, 2020 geophysical data were collected by students from the University of Arizona in cooperation with the US Geologic Survey. The survey was conducted in the Lower Harshaw Creek area of Patagonia, Arizona. The objective of this survey was to define features of the setting for surface water and groundwater across three ranch properties that had varying levels of potable water. Local mineralization in the area led to high concentrations of dissolved solids and low pH in certain wells. DC Resistivity and Transient Electromagnetic were the primary methods used in the survey, with the GEM-2 Frequency Domain Electromagnetic system used in a smaller portion of the survey. These methods allowed for subsurface mapping of the study area with respect to local resistivities. The results of these surveys determined that the likely cause of the varying potability was a shallow rock body containing a high percentage of sulfide minerals. The local geology and nearby area’s mineral occurrences suggest the observed anomalies can best be explained as a buried skarn or epithermal base metal vein-type mineralization. This deposit lies within a shear zone, which caused an uplift of the body under certain sections of the survey area. This zone with the sulfide rich body is the leading theory for the occurrence of non-potable groundwater in the survey area.
    • Geophysical Surveys in the Lead Queen Mine Area, Patagonia Mountains, Arizona

      Moreira Coutinho, Paulo E.; Gordon, Grant J.; Gregorski, Alan C.; LaSala, Blase; Moore, Tim; Morse, Brittany A.; Moulton, Ethan; Sternberg, Ben K.; Zech, Stephanie N.; University of Arizona (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 2018-06-16)
      In late 2015, after abnormally heavy monsoon rains in the Coronado National Forest south of Patagonia Arizona, an orange discharge was observed in the creek bed below the entrance to the abandoned Lead Queen Mine. This caused the U.S. Forest Service and United States Geological Survey (USGS) to mobilize to determine the cause and investigate actions to prevent future occurrences. Our studies included Transient Electromagnetics (NanoTEM), DC resistivity, EM-31 and Ground Penetrating Radar (GPR) surveys around the Lead Queen Mine for the United States Geological Survey. Data collected around Lead Queen Mine show a large highly conductive layer within the immediate area of the mine. Data from the NanoTEM and DC resistivity surveys show an anomaly with resistivities less than 6 ohm-m at depths varying from 20 to 60 meters. This anomaly is present in all TEM transects and the DC resistivity line. The DC resistivity line also shows a high-resistivity area near where the adit has been predicted to be. Further west, near another adit, a low-resistivity layer does not appear until beyond 60 meters depth. Data collected using the EM-31 shows no change in resistivity or conductivity along the stream-bed near Lead Queen Mine. GPR data did not effectively show a response to the adit, even with extensive manipulation using the RADAN software.
    • Geophysical Surveys in the Pima Mining District, Arizona Volume II

      Alalawi, Saleh S. N.; Albehlany, Salah S. H.; Aldossary, Abdulaziz F.; Alhashimi, Rashid A.; Almurshidi, Abdulsam M.; Cathcart, Laura L.; Cole, Sherill L.; Crews, Joseph A.; Crouthamel, David Roger, 1963-; Didace, Didi; et al. (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 1989-02-06)
    • Geophysical Surveys in the Pima Mining District, Arizona Volume I

      Alalawi, Saleh S. N.; Albehlany, Salah S. H.; Aldossary, Abdulaziz F.; Alhashimi, Rashid A.; Almurshidi, Abdulsam M.; Cathcart, Laura L.; Cole, Sherill L.; Crews, Joseph A.; Crouthamel, David Roger, 1963-; Didace, Didi; et al. (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 1989-02-06)
      Geophysical surveys were conducted in the Pima mining district by students from the University of Arizona. The surveys were concentrated along section B-B' from Cooper (1973). The objectives of this survey included: teaching geophysical techniques, mapping regional structure along this profile, and determining which geophysical techniques were most useful for regional .mapping in this area. Controlled source audio-frequency magnetotelluric (CSAMT) surveys successfully mapped depth to basement along this profile. Seismic refraction surveys were not able to map depth to basement. Either the depth to basement was beyond the range of the arrays used in this experiment or there is insufficient contrast in the velocity between the basement and the overlying rocks. A test of the seismic reflection method was carried out using a walk-away noise spread. Possible reflections from basement were noted but were not sufficiently diagnostic to be routinely use able.
    • GEOPHYSICAL SURVEYS NEAR AJO, ARIZONA

      Barber, Lorraine; Crum, Greg; George, David; Ikeda, Carrie; Irvine, Graham; LaBrecque, Doug; LeGrand, Jonathon; Lim, Andrew; Loomis, John; McGill, Robert; et al. (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 1997-06-01)
    • Geophysical Surveys near Chino Valley, Arizona

      Al-senani, Haitham S.; Cox, Melissa R.; Duke, Vasco S.; Duncan, Laurel M.; El-Kaliouby, Hesham; Gandler, Greg L.; Geauner, Scott A.; Manuel, Justin; Powell, Kathy S.; Sternberg, Ben K.; et al. (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 2003-05-07)
      Four different geophysical methods were used near Chino Valley, Arizona in order to map a suspected andesite intrusive, identified as plug 15, which had originally been found using aeromagnetic data already acquired over the area. Magnetic, transient electromagnetic, seismic, and gravity measurements were collected between 3/1/2003-3/2/2003 and 3/22/2003-3/23/2003. The surveys were located near the center of section 35, township 17 North, Range 2 West, just north of Chino Valley, AZ. The magnetic and TEM surveys provided the best indication of the location and depth of the plug. The north-south spatial extent of the plug was estimated to be approximately 600 meters. The depth to the top of the plug was found from the TEM survey to be approximately 300 meters at the center of the survey. The seismic survey did not reach deep enough to find the andesite anomaly and the gravity survey did not appear to be affected by the plug. Magnetic, TEM, and seismic surveys were also performed at another site located approximately 1.25 km northeast of plug 15. The seismic survey did not reach deep enough and the magnetic survey was too short to provide a depth interpretation. The single TEM sounding measured a very high resistivity (approximately 900 ohm-m) at this site.
    • Geophysical Surveys near Fort Huachuca, Arizona

      Call, Christopher J.; Gleason, Arianna E.; Kaunda, Rennie B.; Meneill, Michael J.; Mkandawire, Emmanuel; Palmer, Joe D.; Portney, Barrie S.; Sternberg, Ben K.; Tembo, Jones; Wagner, Shanda L.; et al. (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 2002-05-04)
      The United States Geological Survey (USGS) has been studying the water resources in the vicinity of Fort Huachuca, Arizona. As a part of this study, they contracted an Airborne Electromagnetic (AEM) survey of the region, which was flown in 1997. During the spring semester of 2002, the University of Arizona Geophysics Field Camp class conducted Transient Electromagnetic (TEM) surveys at five locations near AEM flight lines in order to provide an independent test of the resistivity structure. We used 100 X 100 m transmitting loops. A central induction loop array was employed where the transient decay voltage after transmitter turn off was recorded in the center of the transmitter loop. The TEM data were inverted using a smooth modeling program from Zonge Engineering. The resulting apparent resistivity cross sections, in general, showed a resisitivity structure that was similar to the AEM cross sections down to the depth of the investigation of the TEM survey (approximately 200 m). The surface layers (zero to 50 meters) showed high resistivity (30 to 300 ohm-m) and deeper layers showed lower resistivities (10- 30 ohm meters). We also recorded low-induction number (LIN) EM surveys over a sink hole feature in this area. There was a pronounced conductivity high coincident with the sinkhole. Background conductivity readings were typically 10-15 mS/m and over the sinkhole feature the conductivity readings were typically 20-25 mS/m.