Magnetic quantification of urban pollution sources in atmospheric particulate matter

A new method is presented for fast quantification of urban pollution sources in atmospheric particulate matter (PM). The remanent magnetization of PM samples collected in Switzerland at sites with different exposures to pollution sources is analysed. The coercivity distribution of each sample is calculated from detailed demagnetization curves of anhysteretic remanent magnetization (ARM) and is modelled using a linear combination of appropriate functions which represent the contribution of different sources of magnetic minerals to the total magnetization. Two magnetic components, C1 and C2, are identified in all samples. The low-coercivity component C1 predominates in less polluted sites, whereas the concentration of the higher-coercivity component C2 is large in urban areas. The same sites were monitored independently by Hüglin using detailed chemical analysis and a quantitative source attribution of the PM. His results are compared with the magnetic component analysis. The absolute and relative magnetic contributions of component C2 correlate very well with absolute and relative mass contributions of exhaust emissions, respectively. Traffic is the most important PM pollution source in Switzerland: it includes exhaust emissions and abrasion products released by vehicle brakes. Component C2 and traffic-related PM sources correlate well, which is encouraging for the implementation of non-destructive magnetic methods as an economic alternative to chemical analysis when mapping urban dust pollutio

Physical interpretation of isothermal remanent magnetization end-members: New insights into the environmental history of Lake Hovsgul, Mongolia

© 2016. American Geophysical Union. All Rights Reserved.Acquisition curves of isothermal remanent magnetization for 1057 samples of core KDP-01 from Lake Hovsgul (Mongolia) are decomposed into three end-members using non-negative matrix factorization. The obtained mixing coefficients also decompose hysteresis loops, back-field, and strong-field thermomagnetic curves into their related end-member components. This proves that the end-members represent different mineralogical fractions of the Lake Hovsgul sedimentary environment. The method used for unmixing offers a new possibility to apply rock magnetism in paleoecological and paleoclimatic studies. For Lake Hovsgul, it indicates that a low-coercivity component with a covarying paramagnetic phase represents a coarse-grained magnetite fraction from terrigenous influx probably via fluvial transport. A second component with coercivities close to 50 mT is identified as a magnetite fraction related to magnetosomes of magnetotactic bacteria. The third component has coercivities near 85 mT and is identified as greigite of biotic or abiotic origin common in suboxic/anoxic sediments. Significant positive correlations between variations of intensity of all three mineralogical components along the core are found. A rapid drop in all end-member concentrations by more than one order of magnitude at about 20 m depth testifies to a major change of the environmental or geological conditions of Lake Hovsgul. It possibly is related to the onset of MIS 10 marking the termination of arid climate conditions. Short intervals of high productivity are characterized by an abundance of magnetite magnetosomes and may highlight glacial-interglacial transition intervals. For the rest of the core, greigite magnetization substantially exceeds that of magnetite, indicating a predominantly anoxic environment

Assessing the role of natural fracturing by multiscale geophysical investigation

The article presents an estimation of tectonic fracturing role in terrigenous and carbonate blocks containing hydrocarbon deposits. Geological and geophysical datasets of different scale were used to characterize the fracturing of rocks. The good convergence is found between the orientation of natural fracturing by formation microimagers in wells, three-dimensional surface seismic survey, microseismic monitoring of hydraulic fracturing propagation and regional lineament analysis by satellite imagery. The article contains examples of comparison between the direction of maximum horizontal stress axis and stress state and the direction of horizontal wells and fluid flow. New factors of unsuccessful multistage hydraulic fracturing operations in carbonate rocks are considered in the context of natural fracturing systems' kinematics. Complex data analysis of the fracturing at different scales allowed to divide fracturing systems basing on the kinematics. It is shown that the method of structural and geomorphic lineament analysis detected on the satellite images allows to determine the orientation of regional stress field axes for the platform areas with small number of geological outcrops. It is found that during the hydraulic fracturing the main fracture is developed following the system of tectonic fractures and the propagation of the fracture tip is not linear - the fracturing follows both the shear and tensile cracks. It is suggested that the reorientation of the principal stress axes within one field is associated with gently sloping low-amplitude tectonic deformation. The main fundamental conclusion obtained as a result of studies is a justification of the leading role of modern tectonic stress field in the fracturing kinematics. The practical conclusion is a necessity of a selective stimulation of fractured rock blocks to achieve the maximum production for the redeveloped of oil fields

Variability in precipitation, temperature and river runoff in W Central Asia during the past ~2000yrs

The tributary rivers Amu Darya and Syr Darya contribute major amounts of water to the hydrological budget of the endorheic Aral Sea. Processes controlling the flow of water into rivers in the headwater systems in Tien Shan (Kyrgyzstan) and Pamir (Tajikistan) are therefore most relevant. Lake water mineralization is strongly dependent on river discharge and has been inferred from spectrometrically determined gypsum and other salt contents. Comparison of high-resolution mineralization data with tree ring data, other proxies for tracing temperature and snow cover in NW China, and accumulation rates in the Guliya Ice Core indicate that mineralization over the past ~2000. yrs in the Aral Sea reflects snow cover variability and glacier extent in Tien Shan and Pamir (at the NW and W edges of the Tibetan Plateau). Snow cover in W Central Asia is preferentially a winter expression controlled by temperature patterns that impact the moisture-loading capacity over N Europe and NW Asia (Clark et al., 1999). We observed that the runoff, resulting from warmer winter temperatures in W Central Asia and resulting in a reduction of snow cover, decreased between AD 100-300, AD 1150-1250, AD 1380-1450, AD 1580-1680 and during several low frequency events after AD 1800. Furthermore, we observed a negative relationship between the amount of mineralization in the Aral Sea and SW summer monsoon intensity starting with the Little Ice Age. Based on these observations, we conclude that the lake level changes during the past ~. 2000. yrs were mostly climatically controlled. Around AD 200, AD 1400 and during the late 20th century AD, human activities (namely irrigation) may also have synergistically influenced discharge dynamics in the lower river courses. © 2011 Elsevier B.V

Physical interpretation of isothermal remanent magnetization end-members: New insights into the environmental history of Lake Hovsgul, Mongolia

© 2016. American Geophysical Union. All Rights Reserved.Acquisition curves of isothermal remanent magnetization for 1057 samples of core KDP-01 from Lake Hovsgul (Mongolia) are decomposed into three end-members using non-negative matrix factorization. The obtained mixing coefficients also decompose hysteresis loops, back-field, and strong-field thermomagnetic curves into their related end-member components. This proves that the end-members represent different mineralogical fractions of the Lake Hovsgul sedimentary environment. The method used for unmixing offers a new possibility to apply rock magnetism in paleoecological and paleoclimatic studies. For Lake Hovsgul, it indicates that a low-coercivity component with a covarying paramagnetic phase represents a coarse-grained magnetite fraction from terrigenous influx probably via fluvial transport. A second component with coercivities close to 50 mT is identified as a magnetite fraction related to magnetosomes of magnetotactic bacteria. The third component has coercivities near 85 mT and is identified as greigite of biotic or abiotic origin common in suboxic/anoxic sediments. Significant positive correlations between variations of intensity of all three mineralogical components along the core are found. A rapid drop in all end-member concentrations by more than one order of magnitude at about 20 m depth testifies to a major change of the environmental or geological conditions of Lake Hovsgul. It possibly is related to the onset of MIS 10 marking the termination of arid climate conditions. Short intervals of high productivity are characterized by an abundance of magnetite magnetosomes and may highlight glacial-interglacial transition intervals. For the rest of the core, greigite magnetization substantially exceeds that of magnetite, indicating a predominantly anoxic environment

Physical interpretation of isothermal remanent magnetization end-members: New insights into the environmental history of Lake Hovsgul, Mongolia

© 2016. American Geophysical Union. All Rights Reserved.Acquisition curves of isothermal remanent magnetization for 1057 samples of core KDP-01 from Lake Hovsgul (Mongolia) are decomposed into three end-members using non-negative matrix factorization. The obtained mixing coefficients also decompose hysteresis loops, back-field, and strong-field thermomagnetic curves into their related end-member components. This proves that the end-members represent different mineralogical fractions of the Lake Hovsgul sedimentary environment. The method used for unmixing offers a new possibility to apply rock magnetism in paleoecological and paleoclimatic studies. For Lake Hovsgul, it indicates that a low-coercivity component with a covarying paramagnetic phase represents a coarse-grained magnetite fraction from terrigenous influx probably via fluvial transport. A second component with coercivities close to 50 mT is identified as a magnetite fraction related to magnetosomes of magnetotactic bacteria. The third component has coercivities near 85 mT and is identified as greigite of biotic or abiotic origin common in suboxic/anoxic sediments. Significant positive correlations between variations of intensity of all three mineralogical components along the core are found. A rapid drop in all end-member concentrations by more than one order of magnitude at about 20 m depth testifies to a major change of the environmental or geological conditions of Lake Hovsgul. It possibly is related to the onset of MIS 10 marking the termination of arid climate conditions. Short intervals of high productivity are characterized by an abundance of magnetite magnetosomes and may highlight glacial-interglacial transition intervals. For the rest of the core, greigite magnetization substantially exceeds that of magnetite, indicating a predominantly anoxic environment

Physical interpretation of isothermal remanent magnetization end-members: New insights into the environmental history of Lake Hovsgul, Mongolia

© 2016. American Geophysical Union. All Rights Reserved.Acquisition curves of isothermal remanent magnetization for 1057 samples of core KDP-01 from Lake Hovsgul (Mongolia) are decomposed into three end-members using non-negative matrix factorization. The obtained mixing coefficients also decompose hysteresis loops, back-field, and strong-field thermomagnetic curves into their related end-member components. This proves that the end-members represent different mineralogical fractions of the Lake Hovsgul sedimentary environment. The method used for unmixing offers a new possibility to apply rock magnetism in paleoecological and paleoclimatic studies. For Lake Hovsgul, it indicates that a low-coercivity component with a covarying paramagnetic phase represents a coarse-grained magnetite fraction from terrigenous influx probably via fluvial transport. A second component with coercivities close to 50 mT is identified as a magnetite fraction related to magnetosomes of magnetotactic bacteria. The third component has coercivities near 85 mT and is identified as greigite of biotic or abiotic origin common in suboxic/anoxic sediments. Significant positive correlations between variations of intensity of all three mineralogical components along the core are found. A rapid drop in all end-member concentrations by more than one order of magnitude at about 20 m depth testifies to a major change of the environmental or geological conditions of Lake Hovsgul. It possibly is related to the onset of MIS 10 marking the termination of arid climate conditions. Short intervals of high productivity are characterized by an abundance of magnetite magnetosomes and may highlight glacial-interglacial transition intervals. For the rest of the core, greigite magnetization substantially exceeds that of magnetite, indicating a predominantly anoxic environment

Assessing the role of natural fracturing by multiscale geophysical investigation

The article presents an estimation of tectonic fracturing role in terrigenous and carbonate blocks containing hydrocarbon deposits. Geological and geophysical datasets of different scale were used to characterize the fracturing of rocks. The good convergence is found between the orientation of natural fracturing by formation microimagers in wells, three-dimensional surface seismic survey, microseismic monitoring of hydraulic fracturing propagation and regional lineament analysis by satellite imagery. The article contains examples of comparison between the direction of maximum horizontal stress axis and stress state and the direction of horizontal wells and fluid flow. New factors of unsuccessful multistage hydraulic fracturing operations in carbonate rocks are considered in the context of natural fracturing systems' kinematics. Complex data analysis of the fracturing at different scales allowed to divide fracturing systems basing on the kinematics. It is shown that the method of structural and geomorphic lineament analysis detected on the satellite images allows to determine the orientation of regional stress field axes for the platform areas with small number of geological outcrops. It is found that during the hydraulic fracturing the main fracture is developed following the system of tectonic fractures and the propagation of the fracture tip is not linear - the fracturing follows both the shear and tensile cracks. It is suggested that the reorientation of the principal stress axes within one field is associated with gently sloping low-amplitude tectonic deformation. The main fundamental conclusion obtained as a result of studies is a justification of the leading role of modern tectonic stress field in the fracturing kinematics. The practical conclusion is a necessity of a selective stimulation of fractured rock blocks to achieve the maximum production for the redeveloped of oil fields

Assessing the role of natural fracturing by multiscale geophysical investigation

The article presents an estimation of tectonic fracturing role in terrigenous and carbonate blocks containing hydrocarbon deposits. Geological and geophysical datasets of different scale were used to characterize the fracturing of rocks. The good convergence is found between the orientation of natural fracturing by formation microimagers in wells, three-dimensional surface seismic survey, microseismic monitoring of hydraulic fracturing propagation and regional lineament analysis by satellite imagery. The article contains examples of comparison between the direction of maximum horizontal stress axis and stress state and the direction of horizontal wells and fluid flow. New factors of unsuccessful multistage hydraulic fracturing operations in carbonate rocks are considered in the context of natural fracturing systems' kinematics. Complex data analysis of the fracturing at different scales allowed to divide fracturing systems basing on the kinematics. It is shown that the method of structural and geomorphic lineament analysis detected on the satellite images allows to determine the orientation of regional stress field axes for the platform areas with small number of geological outcrops. It is found that during the hydraulic fracturing the main fracture is developed following the system of tectonic fractures and the propagation of the fracture tip is not linear - the fracturing follows both the shear and tensile cracks. It is suggested that the reorientation of the principal stress axes within one field is associated with gently sloping low-amplitude tectonic deformation. The main fundamental conclusion obtained as a result of studies is a justification of the leading role of modern tectonic stress field in the fracturing kinematics. The practical conclusion is a necessity of a selective stimulation of fractured rock blocks to achieve the maximum production for the redeveloped of oil fields

Magnetic quantification of urban pollution sources in atmospheric particulate matter

ISSN:0956-540XISSN:1365-246