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1.
Track densities in feldspar crystals from L16A14 and L16G14 (6–8 cm and 29-21 cm) range from 2.5 × 108/cm2 to > 2 × 109/cm2. No significant difference is found between the two positions. The track densities are similar to those observed in heavily irradiated samples of Apollo 11, 12 and 14 and indicate that these two positions are composed of well mixed materials from a number of sources. This is in contrast to a number of fines samples from Apollo 12 and 14 which are less irradiated and represent relatively recent additions to the lunar surface.  相似文献   

2.
Anthropogenic influences on trace element profiles in dated sediments from estuaries have been often documented, with the vast majority of studies focusing on a short list of high-abundance trace elements. Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) provides a new approach that minimizes sample preparation and contamination while yielding data on a much larger list of elements simultaneously. We present concentrations and enrichment factor profiles for 22 elements at a locality that is 50 km southeast of Baltimore, the principal industrial city on Chesapeake Bay. Samples representing deposition over almost the entire 20th century were obtained from two archived cores collected 20 years apart. The following elements exhibit profiles consistent with a strong anthropogenic influence, i.e. enrichment after 1920 followed by decline after ca.1980, possibly reflecting increased regulatory efforts: Mn, Co, Cu, Zn, Ag, Cd, In, Sn, Sb, Te, Tl, Pb and Bi. As expected, the redox-sensitive elements: Mo, Re and U have similar profiles to one another. Previously, the potentially hazardous elements, Ag, In, Sb, Te, Tl and Bi, have been measured only rarely in estuarine sediments and never in Chesapeake Bay. Our discovery that their profiles track those of well-known pollutants underscores a need to investigate their sources, transport and biogeochemical behavior. Several rarely determined trace elements, Ga, Ge and Nb, exhibit trendless profiles, as do the major elements, Ti and Fe.  相似文献   

3.
Body distribution and growth- and nutritional status-dependent accumulation of 21 trace elements were investigated in harbor seals (Phoca vitulina) stranded in the North Sea coast in 2002. Higher concentrations and burdens of Mn, Se, Mo, Ag, Sn, Hg, and Bi in the liver, Cd in the kidney, As in the blubber, and Co, Sr, and Ba in the bone were observed. Significant positive correlations of hepatic Se, Mo, Ag, Cd, Sn, Hg, Tl, and Bi with standard body length were found, while significant negative relationships were detected for Mn, As, Rb, Sr, and Sb in the liver. Concentrations of Co, Se, Sr, Sn, Hg, and Bi in the liver, V, Sr, Ag, Sn, and Hg in the kidney, V, Mn, Co, Rb, Sr, Sn, Ba, and Pb in the blubber increased with decreasing blubber thickness of harbor seals, indicating enrichment of these elements in the target tissue by emaciation.  相似文献   

4.
Bulk compositions of igneous and microbreccia lithic fragments, glasses, and chondrules from Luna 16 fines as well as compositions of minerals in basaltic lithic fragments were determined with the electron microprobe. Igneous lithic fragments and glasses are divided into two groups, the anorthositic-noritic-troctolitic (hereafter referred to as ANT) and basaltic groups. Chondrules are always of ANT composition and microbreccia lithic fragments are divided into groups 1 and 2. The conclusions reached may be summarized as follows: (1) Luna 16 fines are more similar in composition to Apollo 11 than to Apollo 12 and 14 materials (e.g. Apollo 11 igneous lithic fragments and glasses fall into similar ANT and basaltic groups; abundant norites in Luna 16 and Apollo 11 are not KREEP as in Apollo 12 and 14; Luna 16 basaltic lithic fragments may represent high-K and low-K suites as is the case for Apollo 11; rare colorless to greenish, FeO-rich and TiO2-poor glasses were found in both Apollo 11 and Luna 16; Luna 16 spinels are similar to Apollo 11 spinels but unlike those from Apollo 12). (2) No difference was noted in the composition of lithic fragments, glasses and chondrules from Luna 16 core tube layers A and D. (3) Microbreccia lithic fragments of group 1 originated locally by mixing of high proportions of basaltic with small proportions of ANT materials. (4) Glasses are the compositional analogs to the lithic fragments and not to the microbreccias; most glasses were produced directly from igneous rocks. (5) Glasses show partial loss of Na and K due to vaporization in the vitrification process. (6) Luna 16 chondrules have ANT but not basaltic composition. It is suggested that either liquid droplets of ANT composition are more apt to nucleate from the supercooled state; or basaltic droplets have largely been formed in small and ANT droplets in large impact events (in the latter case, probability for homogeneous and inhomogeneous nucleation is larger. (7) No evidence for ferric iron and water-bearing minerals was found. (8) Occurrence of a great variety of igneous rocks in Luna 16 samples (anorthosite, noritic anorthosite, anorthositic norite, olivine norite, troctolite, and basalt) confirm our earlier conclusion that large-scale melting or partial melting to considerable depth and extensive igneous differentiation must have occurred on the moon.  相似文献   

5.
Total concentrations of As, Cd, Cu, Ni, Pb and Zn were determined in order to assess their changes in contamination levels in roadside soils of long-term abandoned tillage (LAT) belt and short-term abandoned tillage (SAT) belt from a plateau lakeshore of China. Results showed that the mean concentrations of these trace elements except for Cd and Pb were lower than background values. The contamination index values of these trace elements fluctuated and generally decreased with increasing distances from the road in both sampling belts except for Cu and Ni. Both LAT and SAT soils were facing Cd and Pb contamination. The integrated contamination level was more serious in LAT soils compared to SAT soils, with heavy contamination levels at the distances from 5 to 10 m in LAT soils. The effects of the studied rural road on both belts were clearly shown up to 250 m away from the road.  相似文献   

6.
Concentrations of trace elements (V, Cr, Mn, Co, Cu, Zn, Ga, Se, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Hg, Tl, Pb and Bi) were determined in muscle and liver of 12 species of marine fish collected from coastal areas in Malaysia. Levels of V, Cr, Mn, Co, Cu, Zn, Ga, Sr, Mo, Ag, Cd, Sn, Ba and Pb in liver were higher than those in muscle, whereas Rb and Cs concentrations showed the opposite trend. Positive correlations between concentrations in liver and muscle were observed for all the trace elements except Cu and Sn. Copper, Zn, Se, Ag, Cd, Cs and Hg concentrations in bigeye scads from the east coast of the Peninsular Malaysia were higher than those from the west, whereas V showed the opposite trend. The high concentration of V in the west coast might indicate oil contamination in the Strait of Malacca. To evaluate the health risk to Malaysian population through consumption of fish, intake rates of trace elements were estimated on the basis of the concentrations of trace elements in muscle of fish and daily fish consumption. Some specimens of the marine fish had Hg levels higher than the guideline value by US Environmental Protection Agency (EPA), indicating that consumption of these fish at the present rate may be hazardous to Malaysian people. To our knowledge, this is the first study on multielemental accumulation in marine fish from the Malaysian coast.  相似文献   

7.
We report on the petrology, mineralogic properties and contents of major elements and trace elements Ag, Au, Bi, Cd, Co, Cs, Ga, In, Rb, Se, Te, Tl, U and Zn (determined by radiochemical neutron activation analysis) in Yamato 74160, interpreted as an LL7 chondrite. All properties are consistent with this meteorite having been recrystallized and partially melted locally once at temperatures well above 1090°C under conditions such that some minerals (e.g. plagioclase, euhedral pyroxene, tetrataenite) grew from melt pockets and siderophilic and chalcophilic elements were lost by extraction into eutectic melt that drained away. Inhomogeneous plagioclase compositions and mobile element loss suggest shock as the most likely heat source. Yamato 74160, while inferentially chondritic, is a larval achondrite: even higher temperatures and longer times would have been required to cause the separations necessary to transform it to an identifiable achondrite type.  相似文献   

8.
The geochemical and U-series isotopic characteristics of hydrothermal sulfide samples from the Jade site (127°04.5′E, 27°15′N, water depth 1300–1450 m) at Jade site in the Okinawa Trough were analyzed. In the hydrothermal sulfide samples bearing sulfate (samples HOK1 and HOK2), the LREEs are relatively enriched. All the hydrothermal sulfide samples except HOK1 belong to Zn-rich hydrothermal sulfide. In comparison with Zn-rich hydrothermal sulfides from other fields, the contents of Zn, Pb, Ag, Cd, Au and Hg are higher, the contents of Fe, Al, Cr, Co, Ni, Sr, Te, Cs, Ti and U lower, and the 210Pb radioactivity ratios and 210Pb/Pb ratios very low. In the hydrothermal sulfide mainly composed of sphalerite, the correlations between rare elements Hf and U, and Hf and Mn as well as that between dispersive elements Ga and Zn, are strongly positive; also the contents of Au and Ag are related to Fe-sulfide, because the low temperature promotes enrichment of Au and Ag. Meanwhile, the positive correlations between Fe and Bi and between Zn and Cd are not affected by the change of mineral assemblage. Based on the 210Pb/Pb ratios of hydrothermal sulfide samples (3.99×10−5-5.42×10−5), their U isotopic composition (238U content 1.15–2.53 ppm, 238U activity 1.07–1.87 dpm/g, 234U activity 1.15–2.09 dpm/g and 234U/238U ratio 1.07–1.14) and their 232Th and 230Th contents are at base level, and the chronological age of hydrothermal sulfide at Jade site in the Okinawa Trough is between 200 and 2000 yr. Supported by the Pilot Project of Knowledge Innovation Project, Chinese Academy of Sciences (Grant No. KZCX2-YW-211), National Natural Science Foundation of China (Grant Nos. 40830849, 40176020), and Special Foundation for the Eleventh Five Plan of COMRA (Grant No. DYXM-115-02-1-03)  相似文献   

9.
Magnetic susceptibility of 72 cambisol profiles from the vicinity of the Vír dam, NW Moravia was measured. The enhanced susceptibility of topsoil, particularly of the horizon O, was assessed from the aspect of vegetation setting and magnetic mineralogy. Magnetic susceptibility variations with field and temperature as well as frequency dependent susceptibility were applied to indicate magnetic carriers. It was found that the enhanced magnetic susceptibility is caused very likely by the presence of maghemite and magnetite of various grain sizes. Magnetic minerals are pedogenic in origin in all three horizons, while in the O and A horizons they are mostly anthropogenic in origin. Magnetic susceptibility was correlated with contents of trace elements Mo, Cu, Pb, Zn, Ag, As, Cd, Sb, Bi, Hg, Se, furthermore with TOT/C, TOT/S, and 137C. The close association of susceptibility with Pb, Sb and Hg, or also with Mo, As, Se and their similar depth variations suggest a slight anthropogenic input in soils from a long-distant source. The same is valid for 137C, its strong correlation with magnetic susceptibility has been found.  相似文献   

10.
Polymict samples can be used to establish mass-balance constraints regarding the bulk composition of the lunar crust, and to gauge the degree of regional heterogeneity in the composition of the lunar crust. The most ideally polymict type of sample is finely-mixed regolith (lunar soil), or its lithified equivalent, regolith breccia. Fortunately, lunar regolith breccias can occasionally be found at great distances from their points of origin — most of the known lunar meteorites are regolith breccias. We are searching for examples of exotic regolith samples among the Apollo regolith breccia collection. Most of the 21 Apollo regolith breccias analyzed for this study strongly resemble the local soils over which they were collected. Nine regolith breccias from Apollo 16 are surprisingly mature compared to previously-analyzed Apollo 16 regolith breccias, and six of the seven from Apollo 16 Station 5 have lower, more local-soil-like,mg ratios than previously analyzed regolith breccias from this station. Several of the Apollo 14 regolith breccias investigated show significantly highermg, and lower Al, than the local soils.The most interesting sample we have investigated is 14076,1, from a lithology that constitutes roughly half of a 2.0-g pebble. The presence of spherules indicates a regolith derivation for 14076,1, yet its highly aluminous (30 wt.% Al2O3) composition is clearly exotic to the 1.6-km traverse surface over which the Apollo 14 samples were collected. This sample resembles soils from the Descartes (Apollo 16) highlands far more than it does any other polymict sample from the Fra Mauro (Apollo 14) region. The I/sFeO maturity index is extremely low, but this may be a result of thermal annealing. A variety of siderophile elements occur in 14076,1 at typical regolith concentrations. The chemistry of the second most aluminous regolith sample from Apollo 14, 14315, can only be roughly approximated as a mixture of local regolith and 14076,1-like material. However, the low a priori statistical probability for long-distance horizontal transport by impact cratering, along with the relatively high contents of incompatible elements in 14076,1 (despite its high Al content), suggest that this regolith breccia probably originated within a few hundred kilometers of the Appollo 14 site. If so, its compositional resemblance to ferroan anorthosite tends to suggest that the regional crust is, or originally was, far richer in ferroan anorthosite than implied by the meager statistics for pristine rocks from this site. Thus, 14076,1 tends to strengthen the hypothesis that ferroan anorthosite originated as the flotation crust of a global magmasphere.  相似文献   

11.
This study focuses on the trace and rare earth elements(REE) geochemistry of the Nkporo and Ekenkpon Shales of the Calabar Flank.The main aim is to infer their depositional environment and the degree of their metal enrichment.The shale samples were analyzed using inductively coupled plasma mass spectrometry.The results indicated that the mean concentrations of K,Na,and Fe in Nkporo and Ekenkpon Shales are 1.45,0.4,and 4.17 wt%,and 1.11,0.44,and 5.42 wt%;respectively.The Nkporo Shale is enriched with the following trace elements;PMn Sr Ba Zn Ce Rb Zr VCr Ni and depleted in the following trace elements;Ta GeSb Bi Cd Ag Te In Hg.While the Ekenkpon Shale is enriched with the following trace elements;P Mn Ba Sr VCe Zr Rb Cr Zn Ni and depleted in;Sb Ge Bi Ag Ce Te InHg.The concentration of redox-sensitive elements such as V,Ni,Mo,U,Cu,Cr,Re,Cd,Sb,Ti,Mn,and their ratio V/Mo and U/Mo in the black and grey shale samples show different patterns.The REE obtained from the Nkporo and Ekenkpon Shales were PAAS normalized.The Nkporo Shale showed a slightly flat light rare-earth element(LREE),middle rare-earth element(MREE),and heavy rare earth element(HREE) pattern enrichment.Ce/Ce*ranges from 0.95 to 1.09 in Nkporo Shale and 0.67 to 1.40 in Ekenkpon Shale.The Ekenkpon Shale showed a slight LREE,MREE enrichment,and depleted HREE patterns.The Mn contents and U/Mo ratio in Nkporo and Ekenkpon Shales suggests a poor oxygen transitional environment.The V/Mo and V/(V+Ni) ratios indicated that the Nkporo shales were deposited in an anoxic to suboxic conditions and Ekenkpon shales were also deposited under an anoxic to suboxic conditions.The V/Ni ratio indicated that the organic matter in the Nkporo shale is terrigenous while that of the Ekenkpon shales are both terrigenous and marine in origin.  相似文献   

12.
The concentrations of the rare earth elements (REE), K, Rb, Sr, Ba, U, Zr and Cr for the Luna 20 soil and four different Apollo 16 soils are reported. These trace element abundances imply: (1) that the lunar highlands consist of a mixture of rocks rich in large ion lithophile (LIL) elements and LIL-element impoverished anorthosites; or (2) that the bulk of the aluminum-rich crust did not originate by upward segregation of plagioclase in a primitive liquid shell. The Luna 20 soil is distinguished from the Apollo 16 soil by lower aluminum and LIL element abundances.  相似文献   

13.
204Pb, Bi, Tl and Zn in samples from Apollo 17 exhibit relationships not found in samples from other sites.204Pb, Tl and Zn in residues remaining after dilute acid leaching are correlated with one another. Orange soil 74220, which is enriched in204Pb, Tl and Zn, is included in these relationships. In addition the submicron metallic phase generally associated with agglutinate formation is correlated with all three of these elements; this relationship has already been reported for204Pb in other samples. Thus, orange soil and agglutinates appear to be involved in concentrating heavy volatile metals. A process other than mixing is required to account for this. As a consequence of the isolation of the landing site by the surrounding massifs, local supply and recycling of volatile trace elements in soils may account for some of the interelement relations.  相似文献   

14.
The Luna 16 regolith sample differs from Apollo 11, 12 and 14 regolith and basalt samples by having smaller negative Eu and Sr anomalies and nearly chondritic Eu/Sm and Eu/Sr ratios although the overall REE, Ba, Sr and U concentrations are 25 to 45 times chondrites. Major element data, in particular FeO vs. Al2O3, show that the Luna 16 regolith sample is composed of materials that follow a quantitatively different Fe/Al variation than do Apollo 11, 12, 14 and 15 samples. The small Eu and Sr anomalies and the displaced Fe/Al variation are two chemical features unique to the Luna 16 regolith sample. The Luna 16 regolith sample can contain little if any of the rock types abundant at Apollo sites, thus indicating that the unique chemical features are typical of local or nearby materials and indicate a separate petrogenetic province for major component rock types of the Luna 16 regolith.  相似文献   

15.
On the basis of the4He/20Ne ratios in feldspathic particles from Apollo 11, basaltic fragments from Apollo 11, and magnetic separates from Apollo 12 fines, one expects the former to have the highest, and the Apollo 12 material to have the lowest84Kr/132Xe ratios. This is not the case; the84Kr/132Xe ratios from sample 12070 are substantially greater than those from the feldspathic and basaltic fragments in 10084. The trend-reversal in the feldspathic particles could be due to the trapping of genuine primordial lunar Kr and Xe. The reversal in the Apollo 11 basaltic fragments might be due to periodicnear-quantitative loss of the lighter gases by impact heating, with the Apollo 11 fines containing a relatively large proportion of strongly heated fragments.  相似文献   

16.
Concentrations of 19 trace elements (V, Cr, Mn, Fe, Co, Cu, Zn, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, Hg, and Pb) were determined in the liver of the striped dolphins (Stenella coeruleoalba) collected around Japan during 1977–1982 to examine the sex difference, age dependence, and interrelationships among trace elements. Tissue distribution of trace elements was also investigated in one adult and one fetus specimens. Generally, concentrations of Se, Sr, Ag, Cd, Cs, Ba, Hg, and Pb were higher in the tissues of adult than those of fetus, whereas the opposite trend was observed for Cr and Tl. There were no significant sex differences in the trace element levels in the liver. Significant positive correlations between age (0–26.5 years) and hepatic concentrations were found for Ag, Se, Hg, V, Fe, Pb, and Sr, suggesting their age-dependent accumulation in the liver. In contrast, hepatic concentrations of Mn and Zn decreased with age. Significant positive relationships were observed between Se, and Hg, Ag, V, Fe, and Sr in the liver.  相似文献   

17.
Three sediment cores were sampled at Sepetiba Bay and four cores at Ribeira Bay, Rio de Janeiro State, Brazil. Sediment accumulation rates and chronologies were obtained from 210Pb activity-depth profiles. Sediment accumulation rates in Ribera Bay ranged from 1.2 mm y−1 in the inner bay to 2.6 mm y−1 close to its entrance. In Sepetiba Bay two sediment accumulation rates were observed: a lower rate of 0.35 cm y−1 before the 1960s and 0.76 cm y−1 since then. The cause of this change is due to the construction of the Santa Cecília impoundment (1955) that brings water from the Paraíba do Sul Basin into the Guandu River, which increased its flow from the original 20 m3 s−1 to 160 m3 s−1. Concentration of 44 elements was obtained by ICP-MS after total dissolution of samples from two selected cores. The relative differences between the concentrations of crustal elements, such as Al, Fe and Ti are only about 20% (p < 0.05). Cd and Zn are 15 and four times larger in Sepetiba Bay than in Ribeira Bay, respectively. Other major and minor elements show lower statistically significant differences. The enrichment factors and metal inventories show that Sepetiba Bay can be considered polluted with Bi, Cd, Cr, Cu, Sb and Zn. Particularly, Cd and Zn present concentrations three and four times higher than the Brazilian existing limits.  相似文献   

18.
Dust, as a source of trace metal elements, affects the health of society. The spatial and temporal concentrations of dust‐bound trace metals (Cd, Pb, Ni, Zn, Cu, and Mn) in Kuhdasht watershed (456 km2), Lorestan Province, Iran, is investigated. Dust is collected using glass traps placed in ten research stations in the region. The spatial and temporal distribution of dust trace metals are plotted using ARC‐GIS. The highest and the lowest concentrations of Zn (9751150 mg kg?1), Pb (46.352.9 mg kg?1), and Cd (2.443.30 mg kg?1) are obtained in winter, of Ni (98110 mg kg?1) and Cu in autumn (16.053.5 mg kg?1), and of Mn in summer (385505 mg kg?1). The spatial concentrations of dust‐bound trace metals indicate all, except Cu, show a decreasing trend from the mountains toward the plains, similar to that of soil and of dust, except for Zn, which shows higher concentrations in dust than in soil. The potential sources of dust‐bound trace metals and their rate of contamination are also investigated using the enrichment and contamination factors. The major sources of Cd and Zn in the dust of watershed are due to anthropogenic activities or from activities outside the borders.  相似文献   

19.
Three Apollo-16 soils, 61220, 63500 and 65500, having diverse properties were separated into six size fractions and analyzed for 8 volatiles and siderophiles. Relative concentrations of an additional 20 elements were determined in 61220 and 63500. The volatile elements Cd, Zn, In and Ga increase in concentration with decreasing grain size; in the finest fractions the increase is roughly parallel to the increase in specific surface area, and a surface correlation is inferred. The total increase from coarsest (177–500 μm) to finest (<5 μm) fraction is by factors of 10–20 for Zn and Cd in soils 61220 and 63500. Concentrations of elements that are good indicators of KREEP (Sm), mare basalts (Fe) and anorthosites (Ca) show nearly no dependence on size. The preservation of the observed surface correlation throughout regolith evolution suggests that the volatile elements are labile on the lunar surface.Concentration-size distributions of siderophiles show peaks in the 80–300 μm range for each soil, independent of whether they are dominantly extralunar (Ni, Ge, Au, Ir) or lunar (Co) in origin. If this peak results from agglutinate formation, a viable mechanism must allow for incorporation of the extralunar siderophiles. Alternatively, the peak may result from a continuous growth of metal grain size during the evolution of the regolith.  相似文献   

20.
Eight of eleven Apollo 16 rake-sample anorthosites are very similar to each other, to hand-specimen Apollo 16 anorthosites, and to Apollo 15 anorthosites. They have feldspar An96.6, both high- and low-Ca pyroxene with a restricted range of (low-magnesium) composition, minor olivine (～ Fo60), traces of ilmenite and chromite, and originally coarse-grained, but now cataclastic texture. Such ferroan anorthosite is evidently a coherent, distinctive and widespread lunar rock type of cumulate origin which may not necessarily be very closely related genetically to other highland rock types.  相似文献   

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