Location Of Quarries Research Articles

Assessment of Radiation Dose Associated with Background Radionuclides in Quarry Soil at Dawakin-Kudu LGA Kano, Nigeria

Naturally occurring radioactive materials (NORMs) are present in different concentrations in the environment as well as quarry depending on the geological formation of the soil. The assessment of any release of radioactivity into the environment is crucial for safeguarding public health, particularly when this radioactivity has the potential to enter the food chain. The quarry located in Dawakin-Kudu Kano has the potential to exhibit elevated levels of natural radioactivity due to intense mining operations. This study presents the assessment of activity concentration in quarry soil at Dawakin-Kudu with a focus on the transfer mechanism from soil to plant. Soil samples were gathered from a quarry site and farmlands situated around the quarry at Dawakin-kudu, plant samples were also collected from the same farmlands and were all analyzed for natural radioactivity, specifically for 226Ra,232Th, and 40K. The gamma-ray spectrometry method, coupled with the Sodium thallium Iodide NaI (Tl) detector was used to measure the activity concentrations of 226Ra,232Th, and 40K. Activity concentrations of natural radioactivity in soil were generally higher than those recorded in plants. The mean activity concentration of the radionuclides in soil ranges from Highest-to-Lowest values as follows 226Ra: 65.24±1.92 Bqkg-1 – 42.41±1.73 Bqkg-1, 232Th: 182.71±1.44 Bqkg-1 – 114.61±1.25 Bqkg-1, 40K: 597.51±3.81 Bqkg-1 – 321.93±3.55 Bqkg-1. The radiological hazard indices were all determined to assess the radiation hazard of the quarry soil. The radionuclides transfer factor showed a higher value for 40K in the order 40K>232Th >226Ra, this implies high bioconcentration of 40K in plants. The findings suggest that consuming plants grown around the quarry location over an extended period could pose substantial health threats to the public. Consequently, the study area may not be safe for residents in the long run, emphasizing the necessity for continuous monitoring of radioactivity concentrations to mitigate the environmental health implications of accumulated...

Environmental impact of quarrying on air quality in Ebonyi State, Nigeria

AbstractThe insatiable demand for rock supplies has enticed numerous building and construction enterprises to participate in stone quarrying. This paper examines the environmental impact of quarrying on air quality in Ebonyi State, Nigeria. To achieve the main aim of the study, an objective was set to detect air pollutants at the quarry sites. A total of 220 air samples were measured from six points around the quarry locations and recorded in situ for analysis. The samples were measured three times a day (morning, afternoon, and evening) for three days. Gas monitors were used to monitor air pollutants. The generated data were subjected to completely random design (CRD) sampling techniques. The separation of means and tests was performed using Fisher's Least Significant Difference (FLSD) at a significance probability level of 5%. Based on statistical analysis, the findings detected significantly higher concentration levels of particulate matter, nitrogen dioxide, hydrogen sulfide, carbon monoxide, sulfur dioxide, chlorine, volatile organic compounds, ammonia, and hydrogen cyanide in the quarry areas than the value detected in the control area. The findings also confirmed higher noise levels in the locations. It was also observed that the concentration levels of the parameters differed from point to point and at different times of the day. This really means the occurrence of a high rate of air pollution in the study locations. Based on the above findings, it is highly recommended that air pollution control equipment be installed at quarry sites in order to reduce gaseous (pollutant) emissions.

Environmental impact of quarrying on air quality in Ebonyi state, Nigeria

BackgroundThe insatiable demand for rock supplies has enticed numerous building and construction enterprises to participate in stone quarrying. However, this has had an environmental impact on air quality. This paper examines the environmental impact of quarrying on air quality in Ebonyi State, Nigeria. To achieve the main aim of the study, an objective was set to detect air pollutants at the quarry sites. A total of 220 air samples were measured from six points around the quarry locations and recorded in situ for analysis. The samples were measured three times a day (morning, afternoon, and evening) for three days. Gas monitors were used to monitor air pollutants. The generated data were subjected to completely random design (CRD) sampling techniques. The separation of means and tests was performed using Fisher’s Least Significant Difference (FLSD) at a significance probability level of 5%.ResultsBased on statistical analysis, the findings detected significantly higher concentration levels of particulate matter, nitrogen dioxide, hydrogen sulphide, carbon monoxide, sulphur dioxide, chlorine, volatile organic compounds, ammonia, and hydrogen cyanide in the quarry areas than the value detected in the control area. The findings also confirmed higher noise levels in the locations. It was also observed that the concentration levels of the parameters differed from point to point and at different times of the day. This really means the occurrence of a high rate of air pollution in the study locations.ConclusionsBased on the above findings, it is highly recommended that, (i) if situation is not timely addressed, it will lead to a severe environmental disaster or hazard, as nobody selects the air he or she breathes; (ii) air pollution control equipment be installed in-situ at quarry sites where free air flow is available in order to reduce gaseous (pollutant) emissions, and (iii) the seasonal effects, meteorological parameters and time that were influenced by the activities of quarry should be put in check.

Variasi Penggunaan Limbah Crushing Plant Bijih Besi Gunung Batu Sebagai Agregat Halus Terhadap Mutu Beton

The increasing demand for concrete as a construction material has resulted in the depletion of natural resources. This motivates the construction industry to continue to innovate in the manufacture of concrete. The utilization of iron ore waste as a substitute for fine aggregate is one of the solutions. This study aims to determine the optimum composition of iron ore waste as a substitute for fine aggregate on compressive test strength and economic value of concrete mix materials. This study used coarse aggregate from the quarry location of Mount Batu PTP Pelaihari District, Tanah Laut Regency, fine aggregate from the iron ore crushing plant location from the stockpile of Perusda Baratala and ex. Palangkaraya. The testing at the UPT Construction Material Testing Laboratory DPUPRP Tanah Laut Regency, South Kalimantan Province. The results showed that concrete using fine aggregate/sand ex. Palangkaraya has a concrete quality of K-235.94 kg/cm2 or fc'= 19.583 Mpa. As a result, it was found that the concrete mixes were more efficient than the concrete mixes used in the concrete batching plant, and that the concrete mixes were more efficient than the concrete mixes used in the concrete batching plant AK (Coarse aggregat) 54%: AH (fine aggregates) 45% has a concrete quality of K-257.29 kg/cm2 or fc'= 22.849 Mpa. This shows that iron ore waste fine aggregate can be used in concrete mixes

Ecological and health risk assessment of radionuclides and heavy metals of surface and ground water of Ishiagu–Ezillo quarry sites of Ebonyi, Southeast Nigeria

Exposure to heavy metals and natural radionuclides via water sources disposes mankind to deterioration of health. Radionuclides (238U, 232Th, 40K) and heavy metals (Pb, Cr, Cd, As) in surface and borehole waters close to granite quarry sites and the extent of metal contamination for evaluating health risk for individual populations were studied. Mean values of 238U, 232Th, and 40K in surface water (11.56, 8.84 and 35.66 Bq/l) and borehole water (2.68, 10.81 and 18.66 Bq/l) were determined. Total estimated annual effective doses for ingestion of radionuclides via surface and borehole water samples were: children (1.139; 1.058 mSv/y) and adults (2.377; 2.231 mSv/y), adults are more vulnerable to radiation risk. Average heavy metals in both water sources are in order, As >Cr > Pb> Cd. Radionuclides and heavy metals exceeded WHO standards for potable water. Contamination factor, pollution load index, geo-accumulation index, ecological risk and potential ecological risk indices (PERI) showed that surface water contamination is higher than the borehole water within the study areas. Multivariate statistical analysis accounted for 86.30% of the total variance indicating strong correlation between As, Cr, Pb and PERI which was traced to geogenic and anthropogenic sources of the metals that contributed to high potential ecological risk in surface water. Hazard quotient (HQ) and hazard index (HI) (non-carcinogenic) and carcinogenic risk assessment values were within USEPA HQ and HI ≤ 1 and 1 × 10−6 – 1 × 10−4 which portrays little or no significant health effect from the use of studied water sources. Therefore, surface and borehole water within 5 km radius from granite quarry locations should be pretreated before use to avoid long-term effect of pollutants accumulation.

A comparative study on the comminution behavior of diorite rocks

In this article factors that affect the comminution behavior of heterogeneous diorite rocks obtained from two quarry locations in Botswana were investigated. Diorite rocks are in great abundance in Botswana and they are increasingly viewed as a relatively inexpensive and reliable alternative construction material to sustain the infrastructure growth in Botswana. The diorite rock samples collected from both the Central and North-Eastern districts were studied for structural similarities and mineral composition. These two are the main factors that influence material hardness, fracture toughness and particle size distribution (PSD) following breakage, which are important material properties in construction applications (Barry & James, 2016). The aim of the investigation was to comminute and compare the behavior of the rock sample types, under similar experimental conditions in a laboratory jaw crusher as well as in a planetary ball mill. The product PSD was used to theoretically determine and compare power requirements. The experimental results show that the diorite rock sample collected from the central region required 41.58 KWht-1 while the one collected from the north-eastern region required 38.33KWht-1 to fragment from a particle feed in the -50 + 40 mm size range to a product in the -11.2 + 6.3 mm size range, which is a typical construction aggregate size range. The diorite sample collected from the central district was largely characterized by amorphous phase constituents and high silicate/quartz content (12.4%) while the north-eastern diorite was characterized by a high crystalline phase percentage and lower silicate/quartz composition (6.94%). The experimental results show that inherent diorite rock properties play a significant role in determining cost of production and product application in the quarry industry of Botswana.

Evaluation of some Medicinal Plants for Green Belt Development in Rock Quarrying Locations at Lokpaukwu, Abia State, Nigeria

This study evaluated air pollution tolerance plants as well as anticipated performance indices of some medicinal plants growing in the Lokpaukwu rock quarrying area in order ascertain their suitability for green belt development. Two quarry locations A which is older and has a higher level of activity, and B were used for the study with a control location at Abia State University, Uturu. Out of the sixteen dominant plant species identified, five species; Alchornea cordifolia, Baphia pubescens, Napoleona imperialis, Nauclea latifolia and Vitex doniana. were randomly selected for the study. Leaf samples were randomly collected in triplicate from the lowest branch of each selected plants with similar characteristics. Relative water content of plants was significantly higher (p<0.05) at the study area suggesting stomatal occlusion by dust while chlorophyll content was significantly lower at the quarry sites, a clear indication of pollution stress. Chlorophyll content was also lower in all plants at site B, being significant in N. imperialis and V. doniana. N. imperialis had the highest APTI of 19.15 at the quarry site suggesting suitability for green belt development at the quarry site. Based on API, V. doniana is the most suitable for green belt development among the five plant species.

Fracture System and Rock-Mass Characterization by Borehole Camera Surveying: Application in Dimension Stone Investigations in Geologically Complex Structures

The successful exploration of dimension stone mainly depends on the quality, size, and shape of extractable blocks of dimension stone. The investigated area is in the Pelješac Peninsula (Croatia), in the External Dinarides orogeny, built from thick carbonate succession, characterized by relatively small deposits of high-quality dimension stone. These conditions demand challenging geological investigations in the “pre-quarry” phase to find optimal quarry location. The size and shape of dimension stone blocks are mainly controlled by fracture pattern systems. In the rugged, covered terrains, it is very hard to obtain a satisfactory amount of fracture data from the surface, so it is necessary to collect them from the underground. Borehole camera technology can visualize the inner part of the rock mass and measure the fracture characteristics. The main conclusions are as follows: (1) the digital borehole camera technology provides a quick, effective, and low-cost geological survey of fractured rock mass; (2) statistical fracture distribution parameters, P10, fracture spacing, Volumetric Joint Count (Jv) based on borehole wall survey can reflect the integrity of rock mass, providing a solid decision-making base for further investment plans and dimension stone excavation method.

Spatial distribution and landscape impact analysis of quarries and waste dumpsites

This work aimed to develop an assessment tool that can help local officials and the public understanding the main effects surrounding location of quarrying activities and improper disposal of CDW. The specific objectives were to (1) assess the visual impact of quarries and CDW dumpsites at the landscape level and (2) investigate the effect of land conversion to quarries and CDW dumpsites on water runoff volume. The methodology of work involved digitization of individual quarries and CDW dumpsites using very high-resolution satellite imagery. The volume of exploited material was estimated with the use of a Digital Elevation Model. Geographic Object-Based Image Analysis was employed to assess the state of soil cover on identified sites. Visual impact maps were developed using Geographic Information System analysis. The Natural Resource Conservation Service-Curve Number model was adopted to estimate changes in volume of annual surface water runoff. The assessment resulted in mapping individual quarries (i.e., 1,425 quarries over an area of 61,723,800 m2) and CDW dumpsites (i.e., 219 dumpsites over an area of 5,012,100 m2) showing (1) low to complete absence of vegetation recovery on identified sites, (2) improper location of quarries and large extent of visually polluted landscape and (3) increase in surface water runoff. This work demonstrated the ability of using an operational tool to spatially characterize quarries and CDW dumpsites and their impacts on the landscape in the absence of extensive site-specific datasets. The transferability and replicability of this tool count on systematic use of the investigated geospatial techniques.

A Comparative Study on the Comminution Behavior of Diorite Rocks

In this article factors that affect the comminution behavior of heterogeneous diorite rocks obtained from two quarry locations in Botswana were investigated. Diorite rocks are in great abundance in Botswana, and they are increasingly viewed as a relatively inexpensive and reliable alternative construction material to sustain the infrastructural growth in Botswana. The diorite rock samples collected from both the Central and North-Eastern districts were studied for structural similarities and mineral composition. These two are the main factors that influence material hardness, fracture toughness and particle size distribution (PSD) following breakage, which are important materials properties in construction applications. To comminute and compare the behavior of the rock sample types, similar experimental conditions in a laboratory jaw crusher, cone crusher as well as in a planetary ball mill were employed. The product PSD was used to theoretically determine and compare power requirements. The experimental results show that the diorite rock sample collected from the central region required 41.58 KWht-1 while the one collected from the north-eastern region required 38.33KWht-1 to fragment from a particle feed in the -50 + 40 mm size range to a product in the -11.2 + 6.3 mm size range, which is a typical construction aggregate size range. The diorite sample collected from the central district was largely characterized by amorphous phase constituents and high silicate/ quartz content (12.4%) while the north-eastern diorite was characterized by a high crystalline phase percentage and lower silicate/ quartz composition (6.94%). The experimental results show that inherent diorite rock properties play a significant role in determining cost of production and product application in the quarry industry of Botswana.

Artificial intelligence forecasting models of uniaxial compressive strength

The uniaxial compressive strength (UCS) is a vital rock geomechanical parameter widely used in rock engineering projects such as tunnels, dams, and rock slope stability. Since the acquisition of high-quality core samples is not always possible, researchers often indirectly estimate these parameters. The main objective of the present study is to evaluate the performance of the long short term memory (LSTM), deep neural networks (DNN), K-nearest neighbor (KNN), Gaussian process regression (GPR), support vector regression (SVR), and decision tree (DT) to predict the UCS of different rock types of Claystone, Granite, Schist and Sandstone, Travertine, Limestone, Slate, Dolomite and Marl acquired from almost all quarry locations of Iran. 170 data sets, including porosity (n), Schmidt hammer (SH), P-wave velocity (Vp), and point load index (Is(50)) were applied in the methods. Finally, a comparison was made between the results made by the prediction methods. To assess the performance ability of the applied methods, the 5-fold cross-validation (CV) was considered. The results proved that computational intelligence approaches are capable of predicting UCS. On the whole, the GPR with a correlation coefficient (R2) of 0.9955 and a route mean square error (RMSE) of 0.52169, performs best. Lastly, the UCS prediction intelligence methods were ordered as GPR, DT, SVR, LSTM, DNN and KNN, respectively.

About this title - Global Heritage Stone: Worldwide Examples of Heritage Stones

Heritage stones are building and ornamental stones that have special significance in human culture. The papers in this volume discuss a wide variety of such materials, including stones from Europe, Asia, North and South America, Africa and Australia. Igneous (basalt, porphyry, granite), sedimentary (sandstone, limestone) and metamorphic (marble, quartzite, gneiss, soapstone, slate) stones are featured. These have been utilized over long periods of time for a wide range of uses contributing to the historical fabric of the built environment. Many of these stones are of international significance and potential Global Heritage Stone Resources – stones that have the requisite qualities for international recognition by the Heritage Stones Subcommission of the International Union of Geological Sciences. The contributions in this volume bring together diverse information on these stones, ranging from their geological setting and quarry locations to mechanical properties, current availability and uses over time. As such, the papers can serve as an entry into the literature on these important stones.

Geoeducational Value of Quarries Located Within the Ma\u0142opolska Vistula River Gap (E Poland)

Formal and non-formal outdoor learning or field education is the most effective form of interpretation and promotion of geoheritage. Quarries make it possible to look back at the geological past of our planet, and, in many regions, they are the only places where we can observe the exposed bedrock. In E Poland, a considerable number of quarries are located within the area of the Małopolska Vistula River Gap. Herein, Upper Cretaceous, Palaeocene and Miocene marine rocks and Pleistocene sediments of varying origin were quarried. The location of quarries in the proximity of larger and smaller towns enables organising short school trips and conducting geography field classes. What is more, the importance of the town of Kazimierz Dolny, a popular tourist destination located in the northern part of the study area, provides opportunity for enriching the existing “traditional” tourism with offers of geotourism. In the study, the geoeducational value of 53 quarries was assessed by means of a method developed by the authors. This takes into account 20 criteria belonging to four groups of values (scientific, educational, tourist and functional). Additionally, significance was assessed from the perspective of three different audience groups (pupils, university students and non-specific tourists). The assessment made it possible to identify the spatial variation of the geoeducational potential of the quarries, as well as their strengths and weaknesses. Measures were also identified to be taken in the future in order to increase the currently limited use of the quarries for educational purposes.

Tingkat Kualitas Permukiman (Studi Kasus: Permukiman Sekitar Tambang Galian C Kecamatan Weru Kabupaten Sukoharjo)

<em>Settlement is defined as a components combination of housing, environment and life of the societies who live in it. Quality of settlement components can describe how the condition of the settlement itself. Several settlement areas in Weru Subdistrict, Sukoharjo District have a C-type quarry location inside. Based on the Sukoharjo District Spatial Plan, that area is planned as settlement activities. There are other activities that should be supported by the components of the settlements that only planned to accommodate settlement activities. Question in this research is to know the level of settlement quality of each block in settlement area around C-type quarry in Weru Subdistrict seen from (1) nature, (2) shell, (3) infrastucture network, and (4) society. This research is a quantitative research using scoring analysis technique. The result shown that there is difference between each block of settlement. Block 2 has high quality because it has several components with high quality such as buildings, infrastructure network, and the level of public health. The other blocks such as block 1, block 3, block 4, and block 5 have medium quality with several medium quality of components such as green space, road network, economic level and level of public health. Improvement are needed for some components to improve the quality of settlements in each block so that the whole settlements becomes better to lived.</em>

TOURinSTONES: a Free Mobile Application for Promoting Geological Heritage in the City of Torino (NW Italy)

The Piemonte mountains surrounding the city of Torino comprise a wide variety of rocks, characterized by a multitude of minerals, structures and colors. The Alps, because of their long and complex history, have produced a wide variety of ornamental stone used in the town, over the centuries, for both esthetic and structural reasons. TOURinSTONES is an application for mobile phones that allows geotourists to walk in the center of Torino, where the visitor can find Alpine rocks used in palaces and historical monuments as witnesses and tangible symbols of the city. The application consists of 26 historical sites of interest in each of which ornamental stones of historical and scientific interest can be observed in detail. The sites are grouped in four thematic itineraries through which the user can discover the city from the cultural and architectural point of view. By a numbered list of the stones used in all the described monuments, the user can access specific data on each rock including quarry location, petrographic description and utilization in Torino. The mobile application can be downloaded free from the App Store or Google Play respectively for Apple and Android devices.

Identification, preliminary study and valorization of the historical quarries of San Ciprián (Lugo)

The aim of this paper is showing the existence and characteristics of the historical quarries where the building stones were extracted for the construction of the Architectural Heritage of San Ciprián. It is a small town in the north of Lugo (Galicia, NW of Spain) with a long tradition in the use of the natural stone as building material in its architectural heritage. In addition to the benefits in the historical, socio-economic and industrial knowledge, the location of historical quarries is a fundamental task for the conservation plans, allowing to define the original state of the building stone. Moreover, they provide a new contribution to the regional tourist development, including their location and description in the cultural and environmental touristic routes. This study reveals the existence and characteristics of the signs of operation located in the historical quarries associated with the Architectural Heritage of San Ciprián, although in some cases this quarries have disappeared partially or totally. The areas located are: Porto de Riba, Figueiras, Area of the estuary and Lieiro quarry; we cannot affirm the existence of other areas under new constructions, especially in the Porto de Riba and Figueiras.

Rough approximation-based random model for quarry location and stone materials transportation problem

This paper considers a bi-level multi-objective quarry location and stone materials transportation problem for a large-scale construction project with random phenomenon. Based on the characteristics and mechanisms of the problem, the objective functions and constraints are established. To deal with the problem uncertainty, an expected value operator is employed to deal with the random coefficients in the objective functions, and a rough approximation method is adopted to deal with the feasible region, which features constraints with random coefficients. Then a rough approximation-based bi-level multi-objective model is developed as an equivalent crisp model. To solve the complex and nonlinear bi-level multi-objective model, a hybrid genetic algorithm embedded with an interactive fuzzy programming technique is designed as a combined solution method. Finally, the results and a comparison analysis of a case study at the Xiluodu dam construction project are presented to demonstrate the practicality and efficiency of the optimization method.

Silcrete quarries and artefact distribution in the Central Queensland Highlands, Eastern Australia

AbstractA geoarchaeological study of silcrete in the Central Queensland Highlands highlights the importance of geological context in understanding the procurement, use and transport of artefacts. This study shows, by focusing on a newly discovered silcrete quarry, that silcrete formed beneath basalt by silicification of stream sediments and underlying sandstone. Silcrete outcrops are largely restricted to cliffs where the base of the basalt is exposed, narrowing the location of potential quarries. Silcrete artefacts are abundant throughout the region, and there are clear patterns in the use and distribution of different qualities of silcrete. Fine‐grained grain‐supported silcrete is the dominant artefact lithology because of its excellent flaking quality; it is sufficiently versatile to make flake scrapers and retouched microlithic tools. At one occupation site, the mid‐Holocene appearance of backed artefacts and points was accompanied by an increase in the use of fine‐grained grain‐supported silcrete and a decrease in the exploitation of coarse‐grained matrix‐supported silcrete; the latter was less suited to the manufacture of more curated tools. With increasing distance from silcrete outcrops, there is a decrease in the percentage of silcrete artefacts and an increase in the expedient use of local lithologies. However, silcrete's flaking quality justified its dispersal over distances of >80 kilometres from the nearest outcrop.

Consistent joint elastic‐electrical differential effective‐medium modelling of compacting reservoir sandstones

AbstractImproved reservoir characterization and monitoring can be achieved by combining seismic and controlled‐source electromagnetic techniques. This requires developing coherent rock physics descriptions. In this paper we demonstrate consistent joint elastic‐electrical modelling according to the differential effective‐medium theory. We test our modelling against data from a compaction experiment on a set of 11 sandstone core samples from the same quarry location. The presented approach is analogous to calibrating a rock physics model to a particular reservoir based on data from possible well logs and core samples. For simplicity we choose to use multivariable non‐linear regression in the inversion. It shows that this technique is able to identify solutions that are physically sound. However, a more rigorous inversion method might be considered in future implementations. To identify the critical parameters we test the elastic‐electrical sensitivity of the various unknown variables involved. The most sensitive parameters identified are then perturbed during the modelling. The mineralogy consists mainly of quartz, which we assume to be spherical and kaolinite. We use the resistivity to calibrate the aspect ratio of the clay grains and estimate the porosity reduction due to compaction. These values are in turn used in inverse modelling of the bulk and shear moduli. The solid minerals make up the inclusion material in the differential effective‐ medium modelling for both the elastic and electrical properties. Hence, this formulation constitutes a consistent joint elastic‐electrical modelling scheme. We achieve good fits between the model results and the laboratory measurements for most of the samples. The reason for the less good fit with some of the samples might be due to measurement errors in the laboratory. This is supported by the observed abnormal stiffness compaction trends associated with those samples.

(U-Th)/He zircon and archaeological ages for a late prehistoric eruption in the Salton Trough (California, USA)

Research Article| January 01, 2013 (U-Th)/He zircon and archaeological ages for a late prehistoric eruption in the Salton Trough (California, USA) Axel K. Schmitt; Axel K. Schmitt * 1Department of Earth and Space Sciences, University of California, Los Angeles, Los Angeles, California 90095-1567, USA *E-mail: axelk@argon.ess.ucla.edu. Search for other works by this author on: GSW Google Scholar Arturo Martín; Arturo Martín 2Departamento de Geología, CICESE, Km 107 Carretera Tijuana, Ensenada, B.C. C.P. 22800, México Search for other works by this author on: GSW Google Scholar Daniel F. Stockli; Daniel F. Stockli 3Department of Geological Sciences, University of Texas, Austin, Texas 78712, USA Search for other works by this author on: GSW Google Scholar Kenneth A. Farley; Kenneth A. Farley 4Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA Search for other works by this author on: GSW Google Scholar Oscar M. Lovera Oscar M. Lovera 1Department of Earth and Space Sciences, University of California, Los Angeles, Los Angeles, California 90095-1567, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Axel K. Schmitt * 1Department of Earth and Space Sciences, University of California, Los Angeles, Los Angeles, California 90095-1567, USA Arturo Martín 2Departamento de Geología, CICESE, Km 107 Carretera Tijuana, Ensenada, B.C. C.P. 22800, México Daniel F. Stockli 3Department of Geological Sciences, University of Texas, Austin, Texas 78712, USA Kenneth A. Farley 4Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA Oscar M. Lovera 1Department of Earth and Space Sciences, University of California, Los Angeles, Los Angeles, California 90095-1567, USA *E-mail: axelk@argon.ess.ucla.edu. Publisher: Geological Society of America Received: 16 May 2012 Revision Received: 06 Jun 2012 Accepted: 11 Jun 2012 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2012 Geological Society of America Geology (2013) 41 (1): 7–10. https://doi.org/10.1130/G33634.1 Article history Received: 16 May 2012 Revision Received: 06 Jun 2012 Accepted: 11 Jun 2012 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Axel K. Schmitt, Arturo Martín, Daniel F. Stockli, Kenneth A. Farley, Oscar M. Lovera; (U-Th)/He zircon and archaeological ages for a late prehistoric eruption in the Salton Trough (California, USA). Geology 2013;; 41 (1): 7–10. doi: https://doi.org/10.1130/G33634.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract U-Th and (U-Th)/He zircon geochronology redefines the timing of volcanic activity in the Salton Trough (Southern California, USA), the subaerial extension of the incipiently oceanic Gulf of California. U-series disequilibrium corrected (U-Th)/He zircon analyses for a granophyre ejecta clast from the Red Island rhyolite dome indicate an eruption age of 2480 ± 470 a (calendric dates between 0 and 940 Before Common Era, BCE; error at 95% confidence). This eruption age is supported by U-Th zircon crystallization ages for two obsidian-bearing lavas: Red Island (the host for the granophyre) and Obsidian Butte, a prehistoric quarry for obsidian that is widely distributed in southern California and northern Mexico archaeological sites. Lavas and granophyre display overlapping zircon crystallization age distributions that support field and compositional evidence that they are cogenetic and contemporaneous. The (U-Th)/He eruption age is younger and significantly more precise than previous ages for these volcanoes, and is the first indication that the eruption of obsidian flows coincided with human presence in the region. A late prehistoric eruption age agrees with the absence of the Obsidian Butte lithic source among early prehistoric cultural artifacts, previously attributed to submergence of the quarry location during hypothesized persistent flooding by ancient Lake Cahuilla. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.