scholarly journals Geoelectric Exploration of the Purísima-Rumicruz District, Jujuy Province, Argentina

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Luciano López ◽  
Horacio Echeveste ◽  
Mario Tessone ◽  
Marta Alperín ◽  
Ricardo Etcheverry
Keyword(s):  
Black Shale ◽  
Host Rock ◽  
Depositional Environment ◽  
Shear Bands ◽  
Induced Polarization ◽  
Low Resistivity ◽  
Low Degree ◽  
Lower Ordovician ◽  
High Concentrations

Purísima-Rumicruz district consists of several polymetallic veins, rich in copper and lead. The veins have a breccia texture and are located in shear bands, with locally high concentrations of sulfides in a carbonatic gangue. The host rock of the veins consists of a black shale sequence with thin levels of fine sands, with a low degree of metamorphism, and corresponds to the Acoite formation (Lower Ordovician). The depositional environment was an open clastic platform where storm processes prevailed. An exploratory program using induced polarization and resistivity with the dipole-dipole method was carried out with the objective of establishing geoelectric anomalies in depth, which would permit the identification of exploratory targets. The group of veins was divided into three sectors:Purísima,El Brechón, andLa Nueva. Low-resistivity values correspond to faulty zones, some of which are related to surface veins. The presence of diagenetic pyrite in the shales of Acoite formation considerably increases background chargeability (induced polarization) values. However, small chargeability anomalies associated to low-resistivity values represent exploratory targets for the Purísima-Rumicruz district.

DETECTION OF FRACTURED AQUIFER USING COMBINATION OF RESISTIVITY AND INDUCED POLARIZATION ANALYSIS

2015 ◽  
Vol 76 (15) ◽  
Author(s):  
Mohamed Azwan Mohamed Zawawi ◽  
Noorellimia Mat Toridi ◽  
Aimrun Wayayok
Keyword(s):  
Clayey Soil ◽  
Induced Polarization ◽  
Polarization Analysis ◽  
Fractured Aquifer ◽  
Low Resistivity ◽  
Groundwater Occurrence ◽  
Electrical Survey ◽  
Geological Formation ◽  
Subsurface Resistivity

Subsurface geological formation is essential in investigating the groundwater occurrence. The formation can be determined from subsurface resistivity value through electrical survey. However, there is ambiguity in interpreting the subsurface resistivity. Therefore the purpose of this study is to delineate the subsurface geological formation through combination of resistivity and induced polarization analysis. The type of geological formation is determined from resistivity analysis and well lithology. Meanwhile the fracture, water in clayey soil and groundwater occurrence is identified through combination of resistivity and induced polarization analysis.  It has been identified that the study areas consist of fractured aquifer. Possible groundwater fractured area can be indicated by low resistivity ranged from 700 to 2000 Ωm and overlapped with low chargeability ranged from 1 msec to 2 msec. This study provides useful information on nature of groundwater occurrence especially fractured aquifer.

RESISTIVITY, SELF‐POTENTIAL, AND INDUCED‐POLARIZATION SURVEYS OF A VAPOR‐DOMINATED GEOTHERMAL SYSTEM

Geophysics ◽  
1973 ◽  
Vol 38 (6) ◽  
pp. 1130-1144 ◽  
Author(s):  
A. A. R. Zohdy ◽  
L. A. Anderson ◽  
L. J. P. Muffler
Keyword(s):  
Geothermal Field ◽  
Induced Polarization ◽  
Hot Water ◽  
Thermal Waters ◽  
Geothermal System ◽  
Electrical Soundings ◽  
Lateral Extent ◽  
High Concentrations ◽  
Lake Deposits ◽  
Self Potential

The Mud Volcano area in Yellowstone National Park provides an example of a vapor‐dominated geothermal system. A test well drilled to a depth of about 347 ft penetrated the vapor‐dominated reservoir at a depth of less than 300 ft. Subsequently, 16 vertical electrical soundings (VES) of the Schlumberger type were made along a 3.7‐mile traverse to evaluate the electrical resistivity distribution within this geothermal field. Interpretation of the VES curves by computer modeling indicates that the vapor‐dominated layer has a resistivity of about 75–130 ohm‐m and that its lateral extent is about 1 mile. It is characteristically overlain by a low‐resistivity layer of about 2–6.5 ohm‐m, and it is laterally confined by a layer of about 30 ohm‐m. This 30‐ohm‐m layer, which probably represents hot water circulating in low‐porosity rocks, also underlies most of the survey at an average depth of about 1000 ft. Horizontal resistivity profiles, measured with two electrode spacings of an AMN array, qualitatively corroborate the sounding interpretation. The profiling data delineate the southeast boundary of the geothermal field as a distinct transition from low to high apparent resistivities. The northwest boundary is less distinctly defined because of the presence of thick lake deposits of low resistivities. A broad positive self‐potential anomaly is observed over the geothermal field, and it is interpretable in terms of the circulation of the thermal waters. Induced‐polarization anomalies were obtained at the northwest boundary and near the southeast boundary of the vapor‐dominated field. These anomalies probably are caused by relatively high concentrations of pyrite.

RECENT ADVANCES AND APPLICATIONS IN COMPLEX RESISTIVITY MEASUREMENTS

Geophysics ◽  
1975 ◽  
Vol 40 (5) ◽  
pp. 851-864 ◽  
Author(s):  
Kenneth L. Zonge ◽  
Jeffrey C. Wynn
Keyword(s):  
Host Rock ◽  
Electromagnetic Coupling ◽  
Field Measurements ◽  
Complete Removal ◽  
Induced Polarization ◽  
Laboratory Measurements ◽  
Spectral Measurements ◽  
Complex Resistivity ◽  
Geophysical Interpretation ◽  
Rock Alteration

Several years of accumulating complex resistivity spectral measurements have indicated that there are still many unexplored areas in induced polarization surveying that need to be investigated for a more complete understanding of the polarization process. In addition to providing mineral discrimination capabilities, complex resistivity spectra can be used to differentiate between various barren host rock responses, to facilitate the complete removal of electromagnetic coupling, and to identify pipeline, fence, and various other cultural coupling effects. Results of field measurements are presented in an effort to demonstrate the utility of and necessity for making complete spectral measurements for serious geophysical interpretation. Correlation of field measurements with laboratory measurements on core samples from the same area demonstrates that strong electromagnetic coupling can be accurately removed from complete spectra without removing the important rock response. Recent field and laboratory measurements indicate that most, if not all, induced polarization responses attributed to magnetite are not really due to this mineral but can be traced to a host rock alteration response. Also, characteristic host rock signatures for sulfide environments appear to vary according to locality and type of deposits making it impossible to provide a universal set of signatures for sulfide deposits.

Origin, sequence stratigraphy and depositional environment of an upper Ordovician (Hirnantian) deglacial black shale, Jordan

2005 ◽  
Vol 220 (3-4) ◽  
pp. 273-289 ◽  
Author(s):  
Howard A. Armstrong ◽  
Brian R. Turner ◽  
Issa M. Makhlouf ◽  
Graham P. Weedon ◽  
Mark Williams ◽  
...  
Keyword(s):  
Sequence Stratigraphy ◽  
Black Shale ◽  
Depositional Environment ◽  
Upper Ordovician

scholarly journals Actuopaleoichnology of a modern Bay of Fundy macro-tidal flat: analogy with a Mississippian tidal flat deposit (Hartselle Sandstone) from Alabama

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6975
Author(s):  
Louis G. Zachos ◽  
Brian F. Platt
Keyword(s):  
Tidal Flat ◽  
Depositional Environment ◽  
Exposure Period ◽  
Hydrodynamic Characteristics ◽  
Bay Of Fundy ◽  
Grain Texture ◽  
Tidal Regime ◽  
Low Degree ◽  
High Degree ◽  
High Diversity

Trace fossil zonation in the Hartselle Sandstone of Mississippian age (Chesterian: Visean-Serpukhovian) exposed on Fielder Ridge, Alabama is compared with modern macro-tidal flat ichnocoenoses on the Bay of Fundy at Lubec, Maine, and demonstrated to be analogous by sedimentologic and ichnotaxonomic criteria. The modern flat has minimal influence from either waves or freshwater influx, and can be divided into five distinct ichnocoenoses, characterized by surface traces (epichnia) and four sedimentologic facies defined by gross grain texture or hydrodynamic characteristics, but lacking significant surface traces. Several characteristics of tidal flat deposits in a fetch-limited, marine (i.e., non-estuarine), meso- to macro-tidal regime can be used to recognize similar environments as old as the late Paleozoic. These criteria include (1) limited influence of wind and waves on the depositional environment, (2) lack of significant freshwater influence and therefore any persistent brackish environments, (3) a distinct spatial distribution of microenvironments defined by substrate and exposure period, (4) high diversity of epichnial traces directly associated with microenvironments across the tidal flat, (5) generally low degree of reworking of traces by bioturbation but high degree of reworking by tidal currents, and (6) preservation of traces of predation and scavenging behavior on an exposed surface. These features, together with the regional depositional pattern of the Hartselle Sandstone interpreted as tide-influenced bars and shoals, support a meso- to macro-tidal interpretation of the depositional environment.

Reply to “Origin, sequence stratigraphy and depositional environment of an upper Ordovician (Hirnantian) deglacial black shale, Jordan”

2006 ◽  
Vol 230 (3-4) ◽  
pp. 356-360 ◽  
Author(s):  
Howard A. Armstrong ◽  
Brian R. Turner ◽  
Issa M. Makhlouf ◽  
Graham P. Weedon ◽  
Mark Williams ◽  
...  
Keyword(s):  
Sequence Stratigraphy ◽  
Black Shale ◽  
Depositional Environment ◽  
Upper Ordovician
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