Sensory evaluation of olive oil, meaning the official organoleptic assessment of olive oil respectively the "Panel Test" (PT), is based on the standards of the International Olive Council (IOC), as well as on th...Sensory evaluation of olive oil, meaning the official organoleptic assessment of olive oil respectively the "Panel Test" (PT), is based on the standards of the International Olive Council (IOC), as well as on the Regulation (EC) 640/2008 of the European Commission. These regulations lead to the classification of olive oil as "extra virgin" (EVOO), "virgin" (VOO) or "lampant", which however is not sufficient to clearly discriminate between different quality levels within the grade EVOO. The objective of the study at hand was to develop and validate an objective sensory evaluation method for the quality certification of olive oil within the grade EVOO. A new rating system, including a detailed description and evaluation of the complexity and persistence of flavour, was established. First, a comparison between different profile sheets from various olive oil competitions (Ercole Olivario, Premio Biol, Leone D'Oro Mario Solinas Award, among others) and the official profile sheet from the IOC/EC for the panel test (PT) took place. In consecutive steps the basic test procedure from the panel test (PT) then was extended with additional sensory descriptors. Two trained olive oil panels (the German Olive Oil Panel (DOP) and the Swiss Olive Oil Panel (SOP)) were further educated to profile various green and ripe aroma components and to evaluate the complexity of the perceived aroma components and their persistency (descriptor: "harmony/persistency"). This extended methodology was cross-validated over a time period of 3 years between the two panels (DOP/SOP).展开更多
Olivine phenocryst compositions and whole-rock chemical compositions are used to identify primitive picrite basalts from the early part of flood basalt successions in the western part of the Emeishan large igneous pro...Olivine phenocryst compositions and whole-rock chemical compositions are used to identify primitive picrite basalts from the early part of flood basalt successions in the western part of the Emeishan large igneous province (ELIP), southwestern China. The Fo contents of olivine phenocrysts of komatiites with MgO-21.79 wt% range from 85.2% to 91.4%. The composition of unerupted parental melts is calculated from the compositions of the most Fo-rich olivine phenocrysts. These melts had -22 wt% MgO, and originated in mantle with a potential temperature of -1600℃ and at about 4.2 GPa pressure, supporting the conclusion that the generation of ELIP can be attributed to melting of a plume head beginning at -138 km depth.展开更多
In this study, the thermal expansion and heat capacity of San Carlos olivine under high temperature and high pressure are reported. Combining accurate sound velocity data under different P–T conditions with density a...In this study, the thermal expansion and heat capacity of San Carlos olivine under high temperature and high pressure are reported. Combining accurate sound velocity data under different P–T conditions with density and heat capacity data at ambient pressure, the density,adiabatic bulk modulus, shear modulus, and most importantly, thermal expansion and heat capacity, of San Carlos are extracted to 14 GPa by a numerical procedure using classic thermodynamic relationships. These data are in agreement with published findings. To estimate the temperature gradient in the upper mantle, we also report the fitting equations of thermal expansion and heat capacity of San Carlos olivine as a function of both temperature and pressure to the P–T condition of the 410 km discontinuity,which provide the thermodynamic properties with increasing depth in the Earth's interior.展开更多
The effect of packaging materials and lighting conditions on quality of extra virgin olive oil (EVOO) was investigated during six months. The results highlighted an influence of light and type of packaging material ...The effect of packaging materials and lighting conditions on quality of extra virgin olive oil (EVOO) was investigated during six months. The results highlighted an influence of light and type of packaging material on EVOO-quality with storage time. At shelf, all packages maintained EVOO at the end of storage in terms of acidity, peroxide value, K232, while K270 exceeded limit of EVOO in glass and PET-stored oil. Loss of phenols was the highest in glass-stored oil and the lowest in high-density polyethylene (HDPE)-stored oil. In terms of sensory evaluation, glass-stored oil lost EVOO grade after three months and its edible compliance after six months, while HDPE-stored oil maintained EVOO grade 90 days and was virgin after six months. In extended lighting, acidity, peroxide value and K232 did not exceed EVOO grade, while K270 exceeded EVOO grade after 30 days in glass and polyethylene terephthalate (PET)-stored oil and after 90 days in HDPE. The loss of phenols was the largest in glass and smallest in HDPE-stored oil. Glass stored-oil lost organoleptic edible compliance before 90 days, while that in PET was virgin at 90 days and that in HDPE maintained EVOO quality 90 days. At the end of experiment, oils in all packages were not edible. In dark, all packages maintained oil in EVOO quality in terms of all indices. The loss of phenols was marginal but was the least in glass and the highest in HDPE. It was concluded that HDPE bottles conserve stored olive oil at shelf or illumination better than PET or glass, while in dark, glass was superior over plastic.展开更多
Fatty acids' ethyl and methyl esters are not natural components of edible vegetable oils and therefore should not be present in virgin olive oils. Among the quality requirements for extra virgin olive oils, the Inter...Fatty acids' ethyl and methyl esters are not natural components of edible vegetable oils and therefore should not be present in virgin olive oils. Among the quality requirements for extra virgin olive oils, the International Olive Council (IOC) Norm, 2015 review, set limits for the ethyl ester content at ≤ 435 ppm for the 2014/2015 and 2015/2016 harvests and at ≤ 30 ppm for the 2016/2017 harvest. The purpose of this paper is to: (a) determine the alkyl ester content in two extra virgin olive oils (of the Arbequina and Coratina varieties) as parameters of quality at the moment of their elaboration and to assess the length of their shelf life, over a 12 month period at room temperature; (b) determine extra virgin olive oils' free alcohols content as these may esterify due to the free fatty acids present during storage. After 6 months of storage, the Arbequina oil's ethyl ester content was 32 ppm, and the Coratina's was 46 ppm. As a result, the shelf life for both was only about half a year (labeling usually indicates it must be consumed "before 1 year"). However, parameters related to oxidation (peroxide index, K 232, K 270 and AK) remained within the limits set by the International Olive Council (IOC) throughout the year. In conclusion: ethyl ester content is a very fine parameter for assessing the quality of extra virgin in an olive oil and determining the length of its shelf life.展开更多
This research was conducted throughout the years 2008-2010 to study the influence of irrigation water quality on oil quality of "Nabali Muhassan" olive trees. Reclaimed municipal wastewater and fresh water were used...This research was conducted throughout the years 2008-2010 to study the influence of irrigation water quality on oil quality of "Nabali Muhassan" olive trees. Reclaimed municipal wastewater and fresh water were used twice a week using drip irrigation system. Rainfed olive trees of the same farm were taken as control. No significant differences were observed between rainfed, fresh water and reclaimed wastewater treatments in terms of acidity, peroxide values and UV absorbance of the extracted olive oil. Heavy metals and microbiological pathogens were not detected in all tested olive oil samples. Oleic acid was significantly higher in olive oil obtained from rainfed trees than irrigated trees. Linoleic acid content was significantly higher in reclaimed wastewater irrigated trees than the rainfed trees. Total polyphenol contents were significantly higher in oil obtained from rainfed olive trees than oil obtained from the irrigated olive trees. Results of organoleptic analysis showed no significant differences in the fruity attribute within treatments, while the bitter and pungent attributes were higher in olive oil obtained from rainfed trees as compared to that obtained from irrigated trees. No negative attributes were observed in oil obtained from the irrigated or rainfed trees and they were all classified as extra virgin grade.展开更多
The dunite bodies, which extend as the direction of W-E, are exposed to the southeast of Elazlg located within the Eastern Taurus Belt of Turkey. Mafic-Ultramafic section in the Guleman ophiolite consists ofdunite whi...The dunite bodies, which extend as the direction of W-E, are exposed to the southeast of Elazlg located within the Eastern Taurus Belt of Turkey. Mafic-Ultramafic section in the Guleman ophiolite consists ofdunite which containing disseminated chromites, wehrlite, gabbros (isotrope gabbro and layered gabbro) and clinopyroxenite. Dunite blocks above the harzburgite massif have irregular contacts with the enclosing peridotites. Dunite blocks are generally around a few of meters. Dunite blocks consist of gabbro and pyroxenite patches. The origin of dunite blocks are belong to the transition zone of harzburgitic ophiolites which is located at the base of the mafic layered section. They are entirely or largely magmatic formed by olivine and chromite ponds at the base of the crustal magma chamber. The rather around of rock pieces within dunite bodies are foliated such as features have been ascribed to the ophiolite being impregnated by and reacting with a melt. Rocks in the bodies show depleted in incompatible trace elements such as Ba, Nbet al., characteristic of subduction related magma. Furthermore, the high LREE/HREE and high Rb/Th ratios indicates a mantle that has been enrichmented by subduction. As a result, isotopic data, petrographic and geochemical of bodies's result suggest a parental magma derived from an enrichmed source of subduction zone. A few meters of the large dunite bodies, and ascribes to the central dunites a cumulative origin by fractionation from a picritic melt.展开更多
This Study investigated the effect of metrological factors variations between eastern and western foothills on olive oil quality in northern West Bank. Samples were collected from two villages: Assera A1 Shamalia (l...This Study investigated the effect of metrological factors variations between eastern and western foothills on olive oil quality in northern West Bank. Samples were collected from two villages: Assera A1 Shamalia (locates on Western foothills) and Bet Dagan (Locates on Eastern foothills). Differences in metrological factors and harvesting times between the two villages cause differences in olive oil quality and higher content of stigmastadiene in Bet Dagan than Assera olive oil. The higher monthly averages of minimum and maximum temperatures of Bet Dagan cause the increase of Stigmastadiene content of olive oil. While the higher amount of precipitation in Assera; cause higher quality and quantity of produced olive oil in Assera compared to Bet Dagan. The lower relative humidity and longer day hours; in Assera village enhances higher amounts of olive oil accumulation and better quality as this is the favorable conditions for olive oil formation. The compression between Cuba, Crete, Spain and Italy olive oil quality with Palestinian olive oil quality, we found that Palestinian olive oil shows good competition quality parameters for acidity and peroxide values according to the international olive oil council limits compared with these countries olive oil acidity and peroxide values.展开更多
Nowadays, the check of the organoleptic characteristics for the evaluation of extra virgin olive oil (EVOO) quality is regulated by the European Union (EU) authorities, which indicate the use of the panel test (P...Nowadays, the check of the organoleptic characteristics for the evaluation of extra virgin olive oil (EVOO) quality is regulated by the European Union (EU) authorities, which indicate the use of the panel test (PT). It is composed by a team of specialists that give a numerical value to many characteristics about flavours, synthesising a sensory analysis. Each expert answers questions about the aroma by assigning the adequate scores to each oil. The evaluation becomes objective by applying the statistical analysis of all the scores given by the participants: This is the definition of "measure" of Russell. The PT can be considered a true standard "metrological system" (considering the number of questions in the questionnaire), while the perceptions of the testers are the solicitations of it. To allow access to an expensive evaluation process by small companies, this work proposes to "disseminate" the properties of the metrology represented by PT. The results of the PT are arranged in an unsupervised artificial neural network (ANN), the Kohonen map, which represents the synthesis of self-organised output that has only the goal, in this paper, to make readable PT results. The dissemination process is obtained by the gas chromatographic (GC) analysis of each oil sample and through the identification of peaks corresponding to the perceptions. These signals are used for the training of the supervised Multi Layer Perceptron (MLP) ANN, with the back propagation algorithm, whose outputs are represented by the results of the PT. This procedure is exact a "metrological dissemination of a standard" and also the aim of the work: to classify EVOO without always resorting to PT.展开更多
The serpentinized peridotites overlying the subducted zones in the Izu-Bonin-Mariana(IBM) arc system have been interpret as the cause of the low-velocity layer identified beneath the IBM froearc,in turn few earthquake...The serpentinized peridotites overlying the subducted zones in the Izu-Bonin-Mariana(IBM) arc system have been interpret as the cause of the low-velocity layer identified beneath the IBM froearc,in turn few earthquakes occurred along the plate boundary.Chrysotile,which is a low temperature and highly hydrated phase of serpentine with low frictional strength,has been suggested as the low velocity material in the serpentinized peridotites,besides,brucite is inferred to be likely conducive to stable sliding.However,such idea encounters challenging in our serpentinized peridotites from the southern Mariana forearc,which absent both the above minerals.The presence of talc,which characterized by its weak,low-friction and inherently stable sliding behavior,provides new clue.Here we report the occurrence of talc in serpentinized peridotites collected from the landward trench slope of the southern Mariana forearc.We infer that talc is mainly forming as a result of the reaction of serpentine minerals with silica-saturated fluids released from the subducting slab,and talc also occurs as talc veins sometimes.Due to its unique physical properties,talc may therefore play a significant role in aseismic slip in the IBM subduction zone.展开更多
The homologues temperature of a crystalline material is defined as T/Tm, where T is temperature and Tm is the melting (solidus) temperature in Kelvin. It has been widely used to compare the creep strength of crystal...The homologues temperature of a crystalline material is defined as T/Tm, where T is temperature and Tm is the melting (solidus) temperature in Kelvin. It has been widely used to compare the creep strength of crystalline materials. The melting temperature of olivine system, (Mg,Fe)2SiO4, decreases with increasing iron content and water content, and increases with confining pressure. At high pressure, phase transition will lead to a sharp change in the melting curve of olivine. After calibrating previous melting experiments on fayalite (Fe2SiO4), the triple point of fayalite-Fe2SiO4 spinel-liquid is determined to be at 6.4 GPa and 1793 K. Using the generalized means, the solidus and liquidus of dry olivine are described as a function of iron content and pressure up to 6.4 GPa. The change of T/Tm of olivine with depth allows us to compare the strength of the up- per mantle with different thermal states and olivine composition. The transition from semi-brittle to ductile deformation in the upper mantle occurs at a depth where T/Tm of olivine equals 0.5. The lithospheric mantle beneath cratons shows much smaller T/Tm of olivine than orogens and extensional basins until the lithosphere-asthenosphere boundary where T/Tm 〉 0.66, suggesting a stronger lithosphere beneath cratons. In addition, T/Tm is used to analyze deformation experiments on olivine. The results indicate that the effect of water on fabric transitions in olivine is closely related with pressure. The hydrogen-weakening effect and its relationship with T/Tm of olivine need further investigation. Below 6.4 GPa (〈200 kin), T/TIn of olivine controls the transition of dislocation glide from [100] slip to [001] slip. Under the strain rate of 10-12-10-15 s-1 and low stress in the upper mantle, the [100](010) slip system (A-type fabric) becomes dominant when T/TIn〉 0.55-0.60. When T/Tm〈 0.55-0.60, [001] slip is easier and low T/Tm favors the operation of [001](100) slip system (C-type fabric). This is consistent with the widely observed A-type olivine fabric in naturally deformed peridotites, and the C-type olivine fabric in peridotites that experienced deep subduction in ultrahigh-pressure metamorphic terranes. However, the B-type fabric will develop under high stress and relatively low T/Tm. Therefore, the homologues temperature of olivine established a bridge to extrapolate deformation experi- ments to rheology of the upper mantle. Seismic anisotropy of the upper mantle beneath cratons should be simulated using a four-layer model with the relic A-type fabric in the upper lithospheric mantle, the B-type fabric in the middle layer, the newly formed A- or B-type fabric near the lithosphere-asthenosphere boundary, and the asthenosphere dominated by diffusion creep below the Lehmann discontinuity. Knowledge about transition mechanisms of olivine fabrics is critical for tracing the water distribution and mantle flow from seismic anisotropy.展开更多
文摘Sensory evaluation of olive oil, meaning the official organoleptic assessment of olive oil respectively the "Panel Test" (PT), is based on the standards of the International Olive Council (IOC), as well as on the Regulation (EC) 640/2008 of the European Commission. These regulations lead to the classification of olive oil as "extra virgin" (EVOO), "virgin" (VOO) or "lampant", which however is not sufficient to clearly discriminate between different quality levels within the grade EVOO. The objective of the study at hand was to develop and validate an objective sensory evaluation method for the quality certification of olive oil within the grade EVOO. A new rating system, including a detailed description and evaluation of the complexity and persistence of flavour, was established. First, a comparison between different profile sheets from various olive oil competitions (Ercole Olivario, Premio Biol, Leone D'Oro Mario Solinas Award, among others) and the official profile sheet from the IOC/EC for the panel test (PT) took place. In consecutive steps the basic test procedure from the panel test (PT) then was extended with additional sensory descriptors. Two trained olive oil panels (the German Olive Oil Panel (DOP) and the Swiss Olive Oil Panel (SOP)) were further educated to profile various green and ripe aroma components and to evaluate the complexity of the perceived aroma components and their persistency (descriptor: "harmony/persistency"). This extended methodology was cross-validated over a time period of 3 years between the two panels (DOP/SOP).
文摘Olivine phenocryst compositions and whole-rock chemical compositions are used to identify primitive picrite basalts from the early part of flood basalt successions in the western part of the Emeishan large igneous province (ELIP), southwestern China. The Fo contents of olivine phenocrysts of komatiites with MgO-21.79 wt% range from 85.2% to 91.4%. The composition of unerupted parental melts is calculated from the compositions of the most Fo-rich olivine phenocrysts. These melts had -22 wt% MgO, and originated in mantle with a potential temperature of -1600℃ and at about 4.2 GPa pressure, supporting the conclusion that the generation of ELIP can be attributed to melting of a plume head beginning at -138 km depth.
基金supported by the Strategic Priority Research Program (B) of Chinese Academy of Sciences (XDB 18010401)Light of the West Foundation of Chinese Academy of Sciences (Y5CR025000)
文摘In this study, the thermal expansion and heat capacity of San Carlos olivine under high temperature and high pressure are reported. Combining accurate sound velocity data under different P–T conditions with density and heat capacity data at ambient pressure, the density,adiabatic bulk modulus, shear modulus, and most importantly, thermal expansion and heat capacity, of San Carlos are extracted to 14 GPa by a numerical procedure using classic thermodynamic relationships. These data are in agreement with published findings. To estimate the temperature gradient in the upper mantle, we also report the fitting equations of thermal expansion and heat capacity of San Carlos olivine as a function of both temperature and pressure to the P–T condition of the 410 km discontinuity,which provide the thermodynamic properties with increasing depth in the Earth's interior.
文摘The effect of packaging materials and lighting conditions on quality of extra virgin olive oil (EVOO) was investigated during six months. The results highlighted an influence of light and type of packaging material on EVOO-quality with storage time. At shelf, all packages maintained EVOO at the end of storage in terms of acidity, peroxide value, K232, while K270 exceeded limit of EVOO in glass and PET-stored oil. Loss of phenols was the highest in glass-stored oil and the lowest in high-density polyethylene (HDPE)-stored oil. In terms of sensory evaluation, glass-stored oil lost EVOO grade after three months and its edible compliance after six months, while HDPE-stored oil maintained EVOO grade 90 days and was virgin after six months. In extended lighting, acidity, peroxide value and K232 did not exceed EVOO grade, while K270 exceeded EVOO grade after 30 days in glass and polyethylene terephthalate (PET)-stored oil and after 90 days in HDPE. The loss of phenols was the largest in glass and smallest in HDPE-stored oil. Glass stored-oil lost organoleptic edible compliance before 90 days, while that in PET was virgin at 90 days and that in HDPE maintained EVOO quality 90 days. At the end of experiment, oils in all packages were not edible. In dark, all packages maintained oil in EVOO quality in terms of all indices. The loss of phenols was marginal but was the least in glass and the highest in HDPE. It was concluded that HDPE bottles conserve stored olive oil at shelf or illumination better than PET or glass, while in dark, glass was superior over plastic.
文摘Fatty acids' ethyl and methyl esters are not natural components of edible vegetable oils and therefore should not be present in virgin olive oils. Among the quality requirements for extra virgin olive oils, the International Olive Council (IOC) Norm, 2015 review, set limits for the ethyl ester content at ≤ 435 ppm for the 2014/2015 and 2015/2016 harvests and at ≤ 30 ppm for the 2016/2017 harvest. The purpose of this paper is to: (a) determine the alkyl ester content in two extra virgin olive oils (of the Arbequina and Coratina varieties) as parameters of quality at the moment of their elaboration and to assess the length of their shelf life, over a 12 month period at room temperature; (b) determine extra virgin olive oils' free alcohols content as these may esterify due to the free fatty acids present during storage. After 6 months of storage, the Arbequina oil's ethyl ester content was 32 ppm, and the Coratina's was 46 ppm. As a result, the shelf life for both was only about half a year (labeling usually indicates it must be consumed "before 1 year"). However, parameters related to oxidation (peroxide index, K 232, K 270 and AK) remained within the limits set by the International Olive Council (IOC) throughout the year. In conclusion: ethyl ester content is a very fine parameter for assessing the quality of extra virgin in an olive oil and determining the length of its shelf life.
文摘This research was conducted throughout the years 2008-2010 to study the influence of irrigation water quality on oil quality of "Nabali Muhassan" olive trees. Reclaimed municipal wastewater and fresh water were used twice a week using drip irrigation system. Rainfed olive trees of the same farm were taken as control. No significant differences were observed between rainfed, fresh water and reclaimed wastewater treatments in terms of acidity, peroxide values and UV absorbance of the extracted olive oil. Heavy metals and microbiological pathogens were not detected in all tested olive oil samples. Oleic acid was significantly higher in olive oil obtained from rainfed trees than irrigated trees. Linoleic acid content was significantly higher in reclaimed wastewater irrigated trees than the rainfed trees. Total polyphenol contents were significantly higher in oil obtained from rainfed olive trees than oil obtained from the irrigated olive trees. Results of organoleptic analysis showed no significant differences in the fruity attribute within treatments, while the bitter and pungent attributes were higher in olive oil obtained from rainfed trees as compared to that obtained from irrigated trees. No negative attributes were observed in oil obtained from the irrigated or rainfed trees and they were all classified as extra virgin grade.
文摘The dunite bodies, which extend as the direction of W-E, are exposed to the southeast of Elazlg located within the Eastern Taurus Belt of Turkey. Mafic-Ultramafic section in the Guleman ophiolite consists ofdunite which containing disseminated chromites, wehrlite, gabbros (isotrope gabbro and layered gabbro) and clinopyroxenite. Dunite blocks above the harzburgite massif have irregular contacts with the enclosing peridotites. Dunite blocks are generally around a few of meters. Dunite blocks consist of gabbro and pyroxenite patches. The origin of dunite blocks are belong to the transition zone of harzburgitic ophiolites which is located at the base of the mafic layered section. They are entirely or largely magmatic formed by olivine and chromite ponds at the base of the crustal magma chamber. The rather around of rock pieces within dunite bodies are foliated such as features have been ascribed to the ophiolite being impregnated by and reacting with a melt. Rocks in the bodies show depleted in incompatible trace elements such as Ba, Nbet al., characteristic of subduction related magma. Furthermore, the high LREE/HREE and high Rb/Th ratios indicates a mantle that has been enrichmented by subduction. As a result, isotopic data, petrographic and geochemical of bodies's result suggest a parental magma derived from an enrichmed source of subduction zone. A few meters of the large dunite bodies, and ascribes to the central dunites a cumulative origin by fractionation from a picritic melt.
文摘This Study investigated the effect of metrological factors variations between eastern and western foothills on olive oil quality in northern West Bank. Samples were collected from two villages: Assera A1 Shamalia (locates on Western foothills) and Bet Dagan (Locates on Eastern foothills). Differences in metrological factors and harvesting times between the two villages cause differences in olive oil quality and higher content of stigmastadiene in Bet Dagan than Assera olive oil. The higher monthly averages of minimum and maximum temperatures of Bet Dagan cause the increase of Stigmastadiene content of olive oil. While the higher amount of precipitation in Assera; cause higher quality and quantity of produced olive oil in Assera compared to Bet Dagan. The lower relative humidity and longer day hours; in Assera village enhances higher amounts of olive oil accumulation and better quality as this is the favorable conditions for olive oil formation. The compression between Cuba, Crete, Spain and Italy olive oil quality with Palestinian olive oil quality, we found that Palestinian olive oil shows good competition quality parameters for acidity and peroxide values according to the international olive oil council limits compared with these countries olive oil acidity and peroxide values.
文摘Nowadays, the check of the organoleptic characteristics for the evaluation of extra virgin olive oil (EVOO) quality is regulated by the European Union (EU) authorities, which indicate the use of the panel test (PT). It is composed by a team of specialists that give a numerical value to many characteristics about flavours, synthesising a sensory analysis. Each expert answers questions about the aroma by assigning the adequate scores to each oil. The evaluation becomes objective by applying the statistical analysis of all the scores given by the participants: This is the definition of "measure" of Russell. The PT can be considered a true standard "metrological system" (considering the number of questions in the questionnaire), while the perceptions of the testers are the solicitations of it. To allow access to an expensive evaluation process by small companies, this work proposes to "disseminate" the properties of the metrology represented by PT. The results of the PT are arranged in an unsupervised artificial neural network (ANN), the Kohonen map, which represents the synthesis of self-organised output that has only the goal, in this paper, to make readable PT results. The dissemination process is obtained by the gas chromatographic (GC) analysis of each oil sample and through the identification of peaks corresponding to the perceptions. These signals are used for the training of the supervised Multi Layer Perceptron (MLP) ANN, with the back propagation algorithm, whose outputs are represented by the results of the PT. This procedure is exact a "metrological dissemination of a standard" and also the aim of the work: to classify EVOO without always resorting to PT.
基金Supported by the Pilot Project of Knowledge Innovation Project,Chinese Academy of Sciences (No KZCX2-YW-211,KZCX3-SW-223)the National Natural Science Foundation of China (No 40830849)the Special Foundation for the Eleventh Five Plan of COMRA (No DYXM-115-02-1-03)
文摘The serpentinized peridotites overlying the subducted zones in the Izu-Bonin-Mariana(IBM) arc system have been interpret as the cause of the low-velocity layer identified beneath the IBM froearc,in turn few earthquakes occurred along the plate boundary.Chrysotile,which is a low temperature and highly hydrated phase of serpentine with low frictional strength,has been suggested as the low velocity material in the serpentinized peridotites,besides,brucite is inferred to be likely conducive to stable sliding.However,such idea encounters challenging in our serpentinized peridotites from the southern Mariana forearc,which absent both the above minerals.The presence of talc,which characterized by its weak,low-friction and inherently stable sliding behavior,provides new clue.Here we report the occurrence of talc in serpentinized peridotites collected from the landward trench slope of the southern Mariana forearc.We infer that talc is mainly forming as a result of the reaction of serpentine minerals with silica-saturated fluids released from the subducting slab,and talc also occurs as talc veins sometimes.Due to its unique physical properties,talc may therefore play a significant role in aseismic slip in the IBM subduction zone.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41590623 & 41172182)the Ministry of Land Resources Public Welfare Industry Special Scientific Research Projects (Grant No. 201311178-3)
文摘The homologues temperature of a crystalline material is defined as T/Tm, where T is temperature and Tm is the melting (solidus) temperature in Kelvin. It has been widely used to compare the creep strength of crystalline materials. The melting temperature of olivine system, (Mg,Fe)2SiO4, decreases with increasing iron content and water content, and increases with confining pressure. At high pressure, phase transition will lead to a sharp change in the melting curve of olivine. After calibrating previous melting experiments on fayalite (Fe2SiO4), the triple point of fayalite-Fe2SiO4 spinel-liquid is determined to be at 6.4 GPa and 1793 K. Using the generalized means, the solidus and liquidus of dry olivine are described as a function of iron content and pressure up to 6.4 GPa. The change of T/Tm of olivine with depth allows us to compare the strength of the up- per mantle with different thermal states and olivine composition. The transition from semi-brittle to ductile deformation in the upper mantle occurs at a depth where T/Tm of olivine equals 0.5. The lithospheric mantle beneath cratons shows much smaller T/Tm of olivine than orogens and extensional basins until the lithosphere-asthenosphere boundary where T/Tm 〉 0.66, suggesting a stronger lithosphere beneath cratons. In addition, T/Tm is used to analyze deformation experiments on olivine. The results indicate that the effect of water on fabric transitions in olivine is closely related with pressure. The hydrogen-weakening effect and its relationship with T/Tm of olivine need further investigation. Below 6.4 GPa (〈200 kin), T/TIn of olivine controls the transition of dislocation glide from [100] slip to [001] slip. Under the strain rate of 10-12-10-15 s-1 and low stress in the upper mantle, the [100](010) slip system (A-type fabric) becomes dominant when T/TIn〉 0.55-0.60. When T/Tm〈 0.55-0.60, [001] slip is easier and low T/Tm favors the operation of [001](100) slip system (C-type fabric). This is consistent with the widely observed A-type olivine fabric in naturally deformed peridotites, and the C-type olivine fabric in peridotites that experienced deep subduction in ultrahigh-pressure metamorphic terranes. However, the B-type fabric will develop under high stress and relatively low T/Tm. Therefore, the homologues temperature of olivine established a bridge to extrapolate deformation experi- ments to rheology of the upper mantle. Seismic anisotropy of the upper mantle beneath cratons should be simulated using a four-layer model with the relic A-type fabric in the upper lithospheric mantle, the B-type fabric in the middle layer, the newly formed A- or B-type fabric near the lithosphere-asthenosphere boundary, and the asthenosphere dominated by diffusion creep below the Lehmann discontinuity. Knowledge about transition mechanisms of olivine fabrics is critical for tracing the water distribution and mantle flow from seismic anisotropy.