The provenance of modern beach sands from the Barton and Weaver peninsulas of King George Island,South Shetland Islands,West Antarctica was investigated based on their modal composition and geochemical data.The source...The provenance of modern beach sands from the Barton and Weaver peninsulas of King George Island,South Shetland Islands,West Antarctica was investigated based on their modal composition and geochemical data.The source rocks and provenance tectonic setting are interpreted as volcanic and plutonic rocks formed in the magmatic arc setting.This interpretation is generally consistent with the currently distributed bedrocks in the ice-free areas and tectonic setting of King George Island.However,the composition of beach sands of the Barton and Weaver peninsulas is different from distribution of bedrocks exposed in the ice-free areas of both peninsulas.The present beach sands are interpreted as previous subaqueous moraines that were eroded and transported by advancing glaciers across the both peninsulas and deposited in front of the glacier grounding line.In other words,sand sediments in the beaches of the two peninsulas were not derived from bedrocks currently exposed in ice-free areas,but it is interpreted that they were subaqueous moraines before deglaciation and were mixed with sediment derived from wave erosion of bedrocks and sediments of the paleoshoreline during the isostatic uplift of King George Island.Finally,they were reworked under the current beach environments.展开更多
1 Introduction Halunwusu Composite Granites,locates in the northern margin of Belt,between the North Qaidam block and the Central Qilian block,with two phases of magmatic activities.The granites mainly consisits of th...1 Introduction Halunwusu Composite Granites,locates in the northern margin of Belt,between the North Qaidam block and the Central Qilian block,with two phases of magmatic activities.The granites mainly consisits of the Early展开更多
Lithium is a critical strategic metal with signifi-cant reserves in pegmatites,serving as the primary source for global Li production.Apatite has attracted increasing attention as an indicator in petrogenesis studies ...Lithium is a critical strategic metal with signifi-cant reserves in pegmatites,serving as the primary source for global Li production.Apatite has attracted increasing attention as an indicator in petrogenesis studies and for the exploration of ore deposits.In this study,we investigated the volatile compositions and major and trace elements of apatite from the Qiongjiagang pegmatite-type lithium deposit in Himalaya.Apatite derived from spodumene pegmatite exhibits relatively constant and high total rare earth element(ΣREE+Y)concentrations,ranging from 5899 to 8540 ppm.In contrast,apatite in barren pegmatite displays evidently lower(ΣREE+Y)concentrations,varying between 1345 and 3095 ppm.The REE patterns of apatite in spodumene pegmatite generally exhibit a flat shape[(La/Yb)N=1.55-2.15)],with distinctively negative Eu anomalies(Eu_(N)/Eu_(N)^(*)=0.14-0.22),slightly positive Ce anomalies(Ce_(N)/Ce_(N)^(*)=1.03-1.13),and low Y/Ho ratios(28-30).By contrast,apatite in barren pegmatite shows middle rare earth element(MREE)-depleted downward-convex patterns[(La/Yb)N=1.99-20.4)],strongly negative Eu anomalies(Eu_(N)/Eu_(N)^(*)=0.01-0.14),slightly positive Ce anomalies(Ce_(N)/Ce_(N)^(*)=1.10-1.24),and high Y/Ho ratios(30-55,with an average of 50).Overall,the high concentrations ofΣREE(and Y)and low Th/U and Y/Ho ratios can serve as diagnostic indicators to distinguish apatite in spodumene pegmatite from that in barren pegmatite.Furthermore,the flat REE pattern may represent a common feature of apatite from lithium deposits.Differences in the Ce and Eu anomalies between apatite from these two kinds of pegmatites likely reflect formation under different redox conditions.Consequently,based on calculations derived from apatite volatile compositions,the melt associated with spodumene pegmatite may contain higher water content compared to that of the barren one.Therefore,the mineralized pegmatite system may incorporate substantial amounts of H_(2)O-rich fluids,which play a crucial role in lithium mineralization.展开更多
Clay minerals of 34 sediments collected from the northwestern continental shelf of the East China Sea have been determined by X-ray diffraction analysis. The clay mineral distribution is mainly controlled by the sedim...Clay minerals of 34 sediments collected from the northwestern continental shelf of the East China Sea have been determined by X-ray diffraction analysis. The clay mineral distribution is mainly controlled by the sediment source and the dominant circulation pattern. The predominant clay mineral in our study area is illite comprising more than 67% of the whole clay fraction. The highest concentration of illite （〉68%） is found in the southeastern offshore parts beyond the reach of terrigenous input from the Jeju Island. It means that these illites are largely transported by the Kuroshio Current from the South China Sea （SCS）. Smectite is highly concentrated in the northwest middle part and in the outer-shelf mud patch. It seems to be due to the high supply of smectite transported from China where fine-grained sediments are discharged from modern and ancient Huanghe （Yellow） River. The relatively high abundant kaolinite is likely derived from the Changjiang （Yangtze） River via the Taiwan Warm Current. In contrast, large amounts of chlorite and high chlorite/kaolinite ratios occur in the northwestern area, reflecting the transportation by the Yellow Sea Coastal Current from the southern Yellow Sea. The discrimination diagrams clearly show that the sediments in the northwestern East China Sea are ultimately sourced from Chinese rivers, especially from the Huanghe River, whereas the sediment in the northeast part might come from the Jeju Island. The muddy sediments of the Changjiang River＇s submerged delta have much lower 87Sr/S6Sr ratios （0.716 2-0.718 0） than those of the Shandong Peninsular mud wedge （0.721 6-0.724 9）, which are supposed to be originated from the Huanghe River, suggesting the distribution pattern of 87Sr/86Sr ratios as a new tracer to discriminate the provenance of shelf sediments in the study area. The 87Sr/86Sr ratios of the outer-shelf muddy sediments ranged from 0.7169 to 0.7216 in a wide range and was between those of the Huanghe River and Changjiang River sediments, suggesting multiple sources of the sediment in the area.展开更多
From a large number of case studies on terrestrial deposits we know that Late Holocene climate fluctuations have an important impact on the terrestrial environments. However, it is hitherto not clear how the marine se...From a large number of case studies on terrestrial deposits we know that Late Holocene climate fluctuations have an important impact on the terrestrial environments. However, it is hitherto not clear how the marine sediments can be used to shed light on the environment and climate change of the catchment. To provide such insight, we used the major element, trace element and rare earth element（REE） compositions in the southern Yellow Sea（SYS） sediments to reconstruct the changes in weathering and erosion of their source regions. The sediments originate predominantly from the upper crust of East China and are transported into the basin especially by the Yellow River（Huanghe） and to a lesser extent by the Yangtze River（Changjiang）. The chemical index of alteration（CIA; 53.7–59.7） suggests low chemical weathering of the source rocks since the Middle Holocene. This is consistent with the relatively cool and arid climate in North China after the Holocene Megathermal. Comparison of element ratios, including Al/Ca, K/Ca, Al/Na, K/Na, Rb/Sr, Li/Ba and the CIA shows that we can use the latter as a robust proxy for climate change. The CIA-based mean annual precipitation and mean annual temperature show a series of climate fluctuations in the catchment. A relatively warm and humid Period I（5.3–2.9 cal. ka BP）, a relatively cool and dry Period II（2.9–0.9 cal. ka BP） and an increasingly cool and dry Period III（0.9–0.3 cal. ka BP）. These periods can be linked to climate intervals recognized elsewhere.展开更多
Air pollution has become an important issue,especially in Caribbean urban areas,and,particulate matter(PM)emitted by different natural and anthropogenic sources causes environmental and health issues.In this work,we s...Air pollution has become an important issue,especially in Caribbean urban areas,and,particulate matter(PM)emitted by different natural and anthropogenic sources causes environmental and health issues.In this work,we studied the concentrations of PM_(10) and PM_(2.5) sources in an industrial and port urban area in the Caribbean region of Colombia.PM samples were collected within 48-h periods between April and October 2018 by using a Partisol 2000 i-D sampler.Elemental geochemical characterization was performed by X-ray fluorescence(XRF)analysis.Further,ionic species and black carbon(BC)were quantified by ion chromatography and reflectance spectroscopy,respectively.Using the Positive Matrix Factorization(PMF)receptor model,the contributions of PM sources were quantified.The average concentration of PM_(10) was 46.6±16.2μg/m^(3),with high concentrations of Cl and Ca.For PM_(2.5),the average concentration was 12.0±3.2μg/m^(3),and the most abundant components were BC,S,and Cl.The receptor model identified five sources for PM_(10) and PM_(2.5).For both fractions,the contributions of marine sea spray,re-suspended soil,and vehicular traffic were observed.In addition,PM_(2.5) included two mixed sources were found to be fuel oil combustion with fertilizer industry emissions,and secondary aerosol sources with building construction emissions.Further,PM_(10) was found to also include building construction emissions with re-suspended soil,and metallurgical industry emissions.These obtained geochemical atmospheric results are important for the implementation of strategies for the continuous improvement of the air quality of the Caribbean region.展开更多
基金supported by the Korea Polar Research Institute(PE19030)for Y.I.Leethe Polar Academic Program(PE19900),KOPRI for H.S.Lim.
文摘The provenance of modern beach sands from the Barton and Weaver peninsulas of King George Island,South Shetland Islands,West Antarctica was investigated based on their modal composition and geochemical data.The source rocks and provenance tectonic setting are interpreted as volcanic and plutonic rocks formed in the magmatic arc setting.This interpretation is generally consistent with the currently distributed bedrocks in the ice-free areas and tectonic setting of King George Island.However,the composition of beach sands of the Barton and Weaver peninsulas is different from distribution of bedrocks exposed in the ice-free areas of both peninsulas.The present beach sands are interpreted as previous subaqueous moraines that were eroded and transported by advancing glaciers across the both peninsulas and deposited in front of the glacier grounding line.In other words,sand sediments in the beaches of the two peninsulas were not derived from bedrocks currently exposed in ice-free areas,but it is interpreted that they were subaqueous moraines before deglaciation and were mixed with sediment derived from wave erosion of bedrocks and sediments of the paleoshoreline during the isostatic uplift of King George Island.Finally,they were reworked under the current beach environments.
基金supported by the China Geological Survey(grants 1212011086065,12120113033004,121201010000150014-40)the Research Fund for the Doctoral Program of Higher Education of China(grant 20125122110010)
文摘1 Introduction Halunwusu Composite Granites,locates in the northern margin of Belt,between the North Qaidam block and the Central Qilian block,with two phases of magmatic activities.The granites mainly consisits of the Early
基金funded by the Major Research Plan of the National Natural Science Foundation of China(92162323)Strategic Priority Research Program of the Chinese Academy of Sciences(XDA0430101)Guizhou Provincial Science and Technology Projects No.ZK[2023]052.
文摘Lithium is a critical strategic metal with signifi-cant reserves in pegmatites,serving as the primary source for global Li production.Apatite has attracted increasing attention as an indicator in petrogenesis studies and for the exploration of ore deposits.In this study,we investigated the volatile compositions and major and trace elements of apatite from the Qiongjiagang pegmatite-type lithium deposit in Himalaya.Apatite derived from spodumene pegmatite exhibits relatively constant and high total rare earth element(ΣREE+Y)concentrations,ranging from 5899 to 8540 ppm.In contrast,apatite in barren pegmatite displays evidently lower(ΣREE+Y)concentrations,varying between 1345 and 3095 ppm.The REE patterns of apatite in spodumene pegmatite generally exhibit a flat shape[(La/Yb)N=1.55-2.15)],with distinctively negative Eu anomalies(Eu_(N)/Eu_(N)^(*)=0.14-0.22),slightly positive Ce anomalies(Ce_(N)/Ce_(N)^(*)=1.03-1.13),and low Y/Ho ratios(28-30).By contrast,apatite in barren pegmatite shows middle rare earth element(MREE)-depleted downward-convex patterns[(La/Yb)N=1.99-20.4)],strongly negative Eu anomalies(Eu_(N)/Eu_(N)^(*)=0.01-0.14),slightly positive Ce anomalies(Ce_(N)/Ce_(N)^(*)=1.10-1.24),and high Y/Ho ratios(30-55,with an average of 50).Overall,the high concentrations ofΣREE(and Y)and low Th/U and Y/Ho ratios can serve as diagnostic indicators to distinguish apatite in spodumene pegmatite from that in barren pegmatite.Furthermore,the flat REE pattern may represent a common feature of apatite from lithium deposits.Differences in the Ce and Eu anomalies between apatite from these two kinds of pegmatites likely reflect formation under different redox conditions.Consequently,based on calculations derived from apatite volatile compositions,the melt associated with spodumene pegmatite may contain higher water content compared to that of the barren one.Therefore,the mineralized pegmatite system may incorporate substantial amounts of H_(2)O-rich fluids,which play a crucial role in lithium mineralization.
基金This work was supported by the research grant of the Cheju National University of Year 2006.
文摘Clay minerals of 34 sediments collected from the northwestern continental shelf of the East China Sea have been determined by X-ray diffraction analysis. The clay mineral distribution is mainly controlled by the sediment source and the dominant circulation pattern. The predominant clay mineral in our study area is illite comprising more than 67% of the whole clay fraction. The highest concentration of illite （〉68%） is found in the southeastern offshore parts beyond the reach of terrigenous input from the Jeju Island. It means that these illites are largely transported by the Kuroshio Current from the South China Sea （SCS）. Smectite is highly concentrated in the northwest middle part and in the outer-shelf mud patch. It seems to be due to the high supply of smectite transported from China where fine-grained sediments are discharged from modern and ancient Huanghe （Yellow） River. The relatively high abundant kaolinite is likely derived from the Changjiang （Yangtze） River via the Taiwan Warm Current. In contrast, large amounts of chlorite and high chlorite/kaolinite ratios occur in the northwestern area, reflecting the transportation by the Yellow Sea Coastal Current from the southern Yellow Sea. The discrimination diagrams clearly show that the sediments in the northwestern East China Sea are ultimately sourced from Chinese rivers, especially from the Huanghe River, whereas the sediment in the northeast part might come from the Jeju Island. The muddy sediments of the Changjiang River＇s submerged delta have much lower 87Sr/S6Sr ratios （0.716 2-0.718 0） than those of the Shandong Peninsular mud wedge （0.721 6-0.724 9）, which are supposed to be originated from the Huanghe River, suggesting the distribution pattern of 87Sr/86Sr ratios as a new tracer to discriminate the provenance of shelf sediments in the study area. The 87Sr/86Sr ratios of the outer-shelf muddy sediments ranged from 0.7169 to 0.7216 in a wide range and was between those of the Huanghe River and Changjiang River sediments, suggesting multiple sources of the sediment in the area.
基金funded by the"Strategic Priority Research Program"of Chinese Academy of Sciences(Nos.XDA11020102 and XDA05030402)the National Natural Science Foundation of China(No.41376090)+2 种基金the Research Fund for the Doctoral Program of Higher Education of China(No.20120145120017)the Marine Safeguard Project(No.GZH201200503)the Special Fund for Basic Scientific Research of Central Colleges,China University of Geosciences Wuhan
文摘From a large number of case studies on terrestrial deposits we know that Late Holocene climate fluctuations have an important impact on the terrestrial environments. However, it is hitherto not clear how the marine sediments can be used to shed light on the environment and climate change of the catchment. To provide such insight, we used the major element, trace element and rare earth element（REE） compositions in the southern Yellow Sea（SYS） sediments to reconstruct the changes in weathering and erosion of their source regions. The sediments originate predominantly from the upper crust of East China and are transported into the basin especially by the Yellow River（Huanghe） and to a lesser extent by the Yangtze River（Changjiang）. The chemical index of alteration（CIA; 53.7–59.7） suggests low chemical weathering of the source rocks since the Middle Holocene. This is consistent with the relatively cool and arid climate in North China after the Holocene Megathermal. Comparison of element ratios, including Al/Ca, K/Ca, Al/Na, K/Na, Rb/Sr, Li/Ba and the CIA shows that we can use the latter as a robust proxy for climate change. The CIA-based mean annual precipitation and mean annual temperature show a series of climate fluctuations in the catchment. A relatively warm and humid Period I（5.3–2.9 cal. ka BP）, a relatively cool and dry Period II（2.9–0.9 cal. ka BP） and an increasingly cool and dry Period III（0.9–0.3 cal. ka BP）. These periods can be linked to climate intervals recognized elsewhere.
基金financial support from the Departamento Administrativo de CienciaTecnología e Innovación(Colciencias)for Project#141180764164,Contract 815-2018。
文摘Air pollution has become an important issue,especially in Caribbean urban areas,and,particulate matter(PM)emitted by different natural and anthropogenic sources causes environmental and health issues.In this work,we studied the concentrations of PM_(10) and PM_(2.5) sources in an industrial and port urban area in the Caribbean region of Colombia.PM samples were collected within 48-h periods between April and October 2018 by using a Partisol 2000 i-D sampler.Elemental geochemical characterization was performed by X-ray fluorescence(XRF)analysis.Further,ionic species and black carbon(BC)were quantified by ion chromatography and reflectance spectroscopy,respectively.Using the Positive Matrix Factorization(PMF)receptor model,the contributions of PM sources were quantified.The average concentration of PM_(10) was 46.6±16.2μg/m^(3),with high concentrations of Cl and Ca.For PM_(2.5),the average concentration was 12.0±3.2μg/m^(3),and the most abundant components were BC,S,and Cl.The receptor model identified five sources for PM_(10) and PM_(2.5).For both fractions,the contributions of marine sea spray,re-suspended soil,and vehicular traffic were observed.In addition,PM_(2.5) included two mixed sources were found to be fuel oil combustion with fertilizer industry emissions,and secondary aerosol sources with building construction emissions.Further,PM_(10) was found to also include building construction emissions with re-suspended soil,and metallurgical industry emissions.These obtained geochemical atmospheric results are important for the implementation of strategies for the continuous improvement of the air quality of the Caribbean region.
