Biogeochemical Prospecting of Sulphide Minerals in Winder Valley, Balochistan, Pakistan

Abstract: The Mor Range is mountainous terrain in southern Balochistan dominantly occupied by exposures of rocks of the Ferozabad Group which is comprised of Lower‐Middle Jurassic carbonates and siliciclastics. This group contains syngenetic and epigenetic Zn–Pb–Ba mineralization classified as Stratiform Sediment‐Hosted (SSH) and Mississippi Valley Type (MVT) deposits. Three important flora of the Saharo–Sindian, phytogeographical region of Pakistan, namely Tamarix aphyl–la, Salvadora oleoides and Acacia arabica have been studied as a mineralization prospecting tool. Samples of these species were collected from Winder Valley adjoining the Mor Range to prospect for new areas of mineralization, besides the known sulphide deposits. This study revealed the Draber, Thorar, Raj, Mithi and Kanrach localities as new prospect. Quantitative estimation of biophile elements (Zn–Cu–Pb) from the three species was made. A number of new Zn, Cu and Pb anomalies were distinguished in the area. The variation in the constituents of these species from different localities possibly varies with nature and distance from bedrock, mobility, climate, average abundance in the plant ash and exclusion mechanism of the flora. Acacia arabica with deep penetrating roots shows the best results and could be used to delineate new horizons of mineralization. In these species Zn and Cu are relatively concentrated whereas Pb shows limited enrichment. Lead therefore is the element best suited for pinpointing the mineralization owing to its relatively less mobile character. Relationships among Zn–Cu–Pb have been established using scattergrams and triangular variation diagram, which also demonstrate their genetic affiliation. Statistical analyses, such as determination of mean, mode, median, standard deviation, and coefficient of correlation, were also made to improve the raw geochemical data. These biogeochemical methods appear to be suitable in arid climate of Balochistan, if proper attention is paid to species selection.     

A biogeochemical orientation survey in the Moisan gold-mineralized area, Haenam district in Korea

A biogeochemical orientation survey was carried out in the vicinity of an epithermal Au deposit in the Moisan Au–Ag mineralized area, Haenam district in Korea. The Au–Ag bearing quartz veins of the mine occur as narrow open-space fillings within Cretaceous silicic pyroclastics. The vein minerals consist mainly of quartz, sericite, pyrite, chalcopyrite, and galena, with some electrum and argentite. The main objectives of this study were to study the geochemical characteristics of rocks, soils and plants in this area, to investigate the spatial relationship between Au and associated elements in rock–soil–plant system, and to evaluate the applicability of biogeochemical prospecting for Au vein occurrences in Korea. Samples of rocks and soils, and leaves of three plant species (Japanese red pine — P. densiflora, oriental white oak — Q. aliena, Japanese mallotus — M. japonicus) were collected from the target mineralized area and control barren locations, and analyzed for trace elements by instrumental neutron activation analysis. Sampling lines were composed of one slope line which is almost parallel to the mineralized quartz-veins, and four transect lines spaced 100 m apart across the veins at 20 m sampling intervals. From the multi-element data of rock samples (n = 9), high values of Au (maximum 2030 ppb) are spatially related to Au–quartz veins. Soil samples (n = 61) collected from five sampling lines show higher values of Au (24–825 ppb) whereas soil samples from the control locations have lower values of Au (below 25 ppb). Many plant species collected from the vicinity of the veins have high Au contents compared with those at the control locations, but the ranges of Au values are variable among plant species. In a total of 128 samples of plant leaves, Q. aliena yielded Au values of 0.4 to 6.9 ppb, and M. japonicus 0.9 to 4.1 ppb. Gold contents in P. densiflora ranged from 0.1 to 5.6 ppb. Plant leaves from control areas show less than 1.6 ppb Au. The biological absorption coefficient (BAC) of Au in plants decreases in the order of Q. aliena > M. japonicus > P. densiflora. Based on the results of the study, Q. aliena appeared to be the best sampling media for biogeochemical prospecting of Au in the study area.     

Relationships of nitrogen loadings,residential development,and physical characteristics with plant structure in New England salt marshes

We examined the vascular plant species richness and the extent, density, and height ofSpartina species of ten Narragansett Bay, Rhode Island (United States) fringe salt marshes which had a wide range of residential land development and N-loadings associated with their watersheds. Significant inverse relationships of tallS. alterniflora with species richness and with the extent and density ofS. patens and shortS. alterniflora were observed. Extent and density ofS. patens and extent of shortS. alterniflora were positively and significantly related with plant species richness. Marsh elevation and area did not significantly correlate with plant structure. Flood tide height significantly and inversely correlated withS. patens, but did not significantly relate toS. alterniflora or plant species richness. Marsh width significantly and positively correlated with plant species richness andS. patens and inversely correlated with tallS. alterniflora. Significant inverse relationships were observed for N-load, % residential development, and slope withS. patens, shortS. alterniflora, and species richness, and significant positive relationships with tallS. alterniflora. The marsh slope and width were significantly correlated with N-load and residential development that made it difficult to determine to what extent anthropogenic stressors were contributing to the variation in the plant structure among the marshes. At five marhes with similar slopes, there were significant inverse relationships of N-load withS. patens (density and extent) and a positive relationship with tallS. alterniflora (extent). Although there were no significant relationships of slope with the plant metrics among the five sites, other physical factors, such as the flood tide height and marsh width, significantly correlated with the extent and density ofSpartina species. Significant relationships of N-load with plant structure (albeit confounded by the effect of the physical characteristics) support the hypothesis of competitive displacement of dominant marsh plants under elevated nitrogen. It is likely that the varying plant structure in New England marshes is a response to a combination of natural factors and multiple anthropogenic stressors (e.g., eutrophication and sea level rise).     

Phytoremediation potential of native plants grown in the vicinity of Ahangaran lead–zinc mine (Hamedan,Iran)

This study aims to assess the extent of metal accumulation by plants found in a mining area in Hamedan Province in the central west part of Iran. It also investigates to find suitable plants for phytoextraction and phytostabilization as two phytoremediation strategies. Plants with a high bioconcentration factor (BCF) and low translocation factor (TF) have the potential for phytostabilization while plants with both BCFs and TFs greater than one have the potential to be used for phytoextraction. In this study, shoots and roots of the 12 plant species and the associated soil samples were collected. The collected samples were then analyzed by measurement of total concentrations of trace elements (Pb, Zn, Mn and Fe) using atomic absorption spectrophotometer. Simultaneously, BCF and TF parameters were calculated for each element. Results showed that although samples suitable for phytoextraction of Pb, Zn, Mn and Fe and phytostabilization of Fe were not detected, Scrophularia scoparia was the most suitable for phytostabilization of Pb, Centaurea virgata, Echinophora platyloba and Scariola orientalis had the potential for phytostabilization of Zn and Centaurea virgata and Cirsium congestum were the most efficient in phytostabilization of Mn. Present study showed that native plant species growing on contaminated sites may have the potential for phytoremediation.     

The ecological characteristics of the riparian vegetation affected by river overflowing disturbance in the lower Tarim River

Based on data obtained from field investigations, this paper aims to analyze the influence of the river overflow on the desert riparian vegetation and discuss the function of the river overflow on the vegetation restoration at the lower Tarim River. The results show that (1) there are only 17 species, 13 genera and 9 families in the study areas before river overflow, while there are 34 species, 26 genera and 12 families after the overflowing in which 18 species emerged newly; (2) judging by the biodiversity indices, the species diversity and species richness in the river overflowed area increase more significantly than those in the un-overflow area; (3) judging by the importance of different species after years of river overflowing, the annual herbs germinate quickly at first, while the perennial herbs with deep roots or root clones become dominant in the plant community; (4) after several times of river overflowing, some arbors and shrubs such as Populus euphratica and Tamarix ramosissima germinate easily and can dominate gradually in the plant community. The results indicate that the river overflowing restores the severely degraded ecosystem in the lower Tarim River and the function is connected with restoration of eco-hydrological processes in the study areas. The results suggest that experimental overflowing has initiated a process of restoring ecosystem function within the riparian forest.     

新疆罗布泊地区近160年来红柳沙包沉积纹层δ13C与气候重建

红柳沙包具有准确的计年和很强的环境信息储存功能,可以用来恢复数百年来的气候和环境变化.研究发现,罗布泊红柳沙包沉积纹层红柳落叶δ13C序列高频变化受多个气候要素的综合影响,重建的罗布泊地区1839年以来的年平均气温、8～10月空气平均相对湿度及4-5月平均风速,较好地反映了该地区168年来的气候变化.对红柳落叶δ13C...     

Pedo and biogeochemical study of Zinc-Lead deposits of the Besham area,northern Pakistan: its implication in mineral exploration and environmental degradation

The distribution of Zn, Pb, Cu, Cr, Ni and Co in the plant species and soil of the Zn-Pb sulfide deposits of the Besham area in Pakistan has been studied for geochemical prospecting and environmental pollution. Representative samples of several plant species and associated soil were collected and analyzed by the atomic absorption technique. The data suggest that the plants, especially Plectranthus rugosus, Artemisia indica and Verbascum thapsus, in the mineralized area are enriched in Zn, Pb and Cu (Zn>Pb>Cu) and depleted in Cr, Ni and Co. This is correlated with the concentration of these metals in the associated soil. There is no significant correlation of elements among each other in plants and soil; however, strong correlation of Cu, Cr and Ni has been observed between plants and associate soil. Plectranthus rugosus has the greatest capability for accumulating Zn and Pb in its tissues through soil and can be used as a bioindicator for base metal mineral exploration. This plant along with other plant species such as Artemisia indica and Verbascum thapsus having high scavenging ability for Zn and Pb from the soil and could cause serious environmental and health problems in the living organisms of the area.     

Biogeochemical evaluation of Nannorrhops ritchiana : A Mg-flora from Khuzdar, Balochistan, Pakistan

Nannorrhops ritchiana (Mazari Palm) is a distinctive flora growing in the Saharo-Sindian region. It is well distributed on the ultramafic soil, derived from the Bela Ophiolite in the Khuzdar District, Balochistan, Pakistan. Quantitative estimation of Ca, Mg, Fe and Ni in soil and plant ash has been carried out. The constituents of plant ash have been discussed in relation to soil chemistry, pH, climate, mobility, average abundance in plant ash and exclusion mechanism of the flora. Relationship among Ca, Mg, Fe and Ni has been established using scattergrams to evaluate the biogeochemistry of the plant. High contents of Mg and high coefficient of biological absorption allow it to be classed as Mg-flora. Both Ca and Fe appeared to be antagonistic to Mg. The metal assemblage ofN. ritchiana nicely reflected the nature of the bed rock as being serpentinized ultramafic, and its corresponding soils. Good exclusion mechanism ofN. ritchiana did not allow it to absorb high Ni from the soil. Relatively high concentrations of Ni inN. ritchiana from the Baran Lak area can be used to localize Ni-mineralization in the study area. Statistical analyses, such as minimum, maximum, mean, mode, median, standard deviations, and coefficient of correlation, were also made to improve raw geochemical data and interpretations.     

Major and trace elements in plants and soils in Horton Plains National Park,Sri Lanka: an approach to explain forest die back

Forest die back has been observed from 1980s in the montane moist forest of Horton Plains in the Central Sri Lanka for which the aetiology appears to be uncertain. The concentration levels of Na, K, Ca, Mg, Fe, Mn, Cu, Ni, Zn and Pb in canopy leaves, bark and roots, which were collected from dying and healthy plants of three different endemic species, Calophyllum walkeri, Syzygium rotundifolium and Cinnamomum ovalifolium, from three different die back sites were studied. Soils underlying the plants were also analyzed for their extractable trace metals and total contents of major oxides. Analysis of dead and healthy plants does not show any remarkable differences in the concentrations of studied trace elements. The results show that there is a low status of pollution based on the concentrations of chemical elements of environmental concern. Extractable and total trace element analysis indicates a low content of Ca in soils due to high soil acidity that probably leads to Mg and Al toxicity to certain plants. Relatively high Al levels in the soil would affect the root system and hamper the uptake and transport of essential cations to the plant. It therefore seems that the forest declining appears to be a natural phenomenon, which occurs due to the imbalance of macro and micronutrients in the natural forest due to excessive weathering and the continuous leaching of essential elements.     

Epidermal characters of Tamarix L.(Tamaricaceae) from Northwest China and their taxonomic and palaeogeographic implications

The taxonomical position of species of the genus Tamarix(Tamaricaceae) has been criticized because of their gross morphological similarities(such as slender, smooth and reddish-brown branches,grey-green foliage and scale leaves), and their systematic relationships remain unclear. In this paper, the leaf epidermal features of 17 species from China are studied based on the micro-morphological characters of the epidermal cells, stomata, salt glands, papillae and epidermal hairs. According to the studies, the leaf epidermal features, together with the character of the flower, are taxonomically clearly distinct. The establishment of Tamarix albiflonum is consolidated. Tamarix korolkowi and Tamarix ramosissima have minimal differences in epidermal characters, and the former is suggested to be a junior synonym. Tamarix ramosissima, Tamarix tarimensis, Tamarix arceuthoides and Tamarix hohenackeri are most similar with respect to their leaf epidermis; considering the common morphological features, habit, distribution and especially the hybridization, it is suggested that these four species are closely genetically related and that the variations among them are probably intraspecific. The new taxonomical evidence indicates the occurrence of13 species and four variants in China. Presently, Tamarix is a typical plant of arid and semi-arid regions, but its Eocene ancestors lived in warm and humid climates in the coastal areas of the ancient Mediterranean Sea.Thus, the papillae or epidermal hairs, which are outgrowths of the outer epidermal cells facilitating the leaf to respond to water stress and commonly seen in the plants growing in arid or semi-arid areas rather than the plants in warm and humid climates, are of relatively recent origin in Tamarix. The primitive species lack papillae or epidermal hairs, while in evolved species these structures are abundant. Based on the ecological adaptations of the epidermal features, the palaeogeographic implications of Tamarix in the Late Cenozoic of Northwest China are also discussed.     

Biogeochemical investigation in south eastern Andhra Pradesh: the distribution of rare earths, thorium and uranium in plants and soils

The concentration of rare earth elements (REE), thorium and uranium were determined by inductively coupled plasma mass spectrometry (ICP−MS) in the plant species, Pterocarpus santalinus, P. marsupium and P. dalbergioides, and the soils on which they were growing. Higher concentrations of lanthanum (La), cerium (Ce) were observed in both plants and soils. Large amounts of thorium and uranium were found in the soil. In all tree species, the concentration of REEs were higher in the heartwood than the leaves. The heartwood of P. santalinus accumulated larger quantities of uranium (average concentration of 1.22 ppm) and thorium (mean value of 2.57 ppm) than the other two species. Received: 8 September 1999 · Accepted: 15 December 1999     

Removal of selected metals from drinking water using modified powdered block carbon

This paper presents the possible alternative removal options for the development of safe drinking water supply in the trace elements affected areas. Arsenic and chromium are two of the most toxic pollutants, introduced into natural waters from a variety of sources and causes various adverse effects on living bodies. Performance of three filter bed method was evaluated in the laboratory. Experiments have been conducted to investigate the sorption of arsenic and chromium on carbon steel and removal of trace elements from drinking water with a household filtration process. The affinity of the arsenic and chromium species for Fe/Fe₃C (iron/iron carbide) sites is the key factor controlling the removal of the elements. The method is based on the use of powdered block carbon (PBC), powder carbon steel and ball ceramic in the ion-sorption columns as a cleaning process. The PBC modified is a satisfactory and practical sorbent for trace elements (arsenite and chromate) dissolved in water.     

Metal levels in estuarine macrophytes: Differences among species

With the aim of studying the interspectific differences in the bioaccumulation of a series of elements in six species of estuarine macrophytes, we measured the concentrations of various metals (Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn), as well as C and N, in several species of macroalgae and one species of seagrass in estuaries in northwest Spain. To facilitate the interpretation of the results, we also determined the concentrations of the same metals in sediments. Contamination by particulate metal did not appear to be important. The levels of Cu in the different species were generally high in comparison with those found in similar studies; in contrast, the concentrations of Pb and Zn were relatively low. The metal concentrations showed greater variability and a distibution that was further from normal than those of C and N. In general the highest concentrations of elements were found inEnteromorpha spp. andZostera noltii, and the lowest occurred inUlva spp. There were several significant positive correlations among tissue concentrations of Cr, Cu, and Ni. There were also significant correlations between tissue concentrations of N and Zn, suggesting possible synergetic effects between them. Cluster analysis clearly revealed that the chemical composition ofZ. noltii differed from that of the macroalage. Macroalgae were not grouped according to their taxonomic position, therefore it appears that the concentrations of the elements depended more on the ecological traits of the macroalgal species rather than on any possible, physiological differences among different taxonomic groups. Of the species studied,Ascophyllum nodosum andEnteromorpha spp. appeared to be the best biomonitors of metal contamination.     

Effects of increased inundation and wrack deposition on a high salt marsh plant community

Salt marshes respond to both slowly increasing tidal inundation with sea level rise and abrupt disturbances, such as storm-induced wrack deposition. The effects of inundation pattern and wrack deposition have been studied independently but not in combination. We manipulated inundation of tidal creek water and wrack presence individually and in combination, in two neighboring communities within a Virginia high salt marsh during 1994 and 1995. The effects of these manipulations were assessed by measurements of aboveground plant biomass. Altered inundation by itself produced little response in the various categories of plant biomass measured. Wrack deposition affected all species (i.e., Juncus roemerianus, Spartina patens, and Distichlis spicata) showing a significant reduction in aboveground biomass, as expected. Recovery after wrack deposition was dependent on the species. S. patens and D. spicata recovered from wrack deposition within one growing season, while J. roemerianus did not. Because the effects of wrack deposition greatly exceeded those of experimentally increased inundation, the possible interactions between the two were masked. Increased inundation may have inhibited the colonization of bare areas by some species after the removal of wrack from an area, although statistical significance at α=0.01 was not reached. Our results confirm that wrack deposition can cause the redistribution of species within the high marsh community. Altered inundation may have a greater effect on the re-establishment of the plant community after wrack deposition than it does without wrack deposition.     

Effects of climatic factors and soil salinity on the distribution of vegetation types containing <Emphasis Type="Italic">Anabasis aphylla</Emphasis> in Iran: a multivariate factor analysis

In order to identify factors affecting the distribution of Anabasis aphylla in rangelands of Iran, 132 climatic parameters which contributed to the species distribution (based on the ecological conditions of the study area) were selected. Factor analysis was then applied to determine the most important factors affecting species distribution. In the next stage, the spatial distribution map of An. aphylla throughout Iran was prepared. According to the results of factor analysis, ten factors with Eigenvalues greater than one explained 92.96% of the total variance. These factors were temperature below zero, winter rainfall, summer rainfall, wind, sunlight, warm season dust, rainfall in fall, thunderstorms, relative humidity in September, and cloudy days in winter and explained 34.34, 9.71, 9.69, 8.85, 5.99, 5.35, 4.97, 4.78, 4.73, and 4.51% of the total variance, respectively. Moreover, six vegetation types containing An. aphylla were identified throughout the country. These types were distributed in the central areas of Iran and also in patches within the southeastern parts of the country. The results showed that in addition to the nine above climatic factors, soil variables particularly salinity influence establishing the vegetation types in their distribution areas and the vegetation types are located in low to relatively high salinity, and soils with these salinity levels (low to relatively high salinity) are suitable for these types of plants.     

AUSTRALIS: A new tool for the study of isotopic systems and geochronology in mineral systems

AUSTRALIS (AMS for Ultra Sensitive TRAce eLement and Isotopic Studies) is a microbeam accelerator mass spectrometry (AMS) system designed for in situ microanalysis of geological samples for trace elements and radiogenic and stable isotope data. The AMS method eliminates molecular and isobaric interferences in in situ mass spectrometric measurements, opening up new opportunities in geochronology and tracer applications. Tests have been carried out for measurements of Pb, S and Os isotopes, conducted mainly at 1.5 MV accelerating voltage. In Pb and S tests, precision as high as 0.3‰ has been obtained, made possible by a fast isotope switching system to counter the effect of instabilities in the ion source and beam transport system. In trace‐element analysis, a detection limit for Au at the sub‐ppb level was obtained.     

Physiological acclimation strategies of riparian plants to environment change in the delta of the Tarim River,China

The occurrence and development of riparian forests, which were mainly dominated by mesophytes species related closely with surface water. Since there was no water discharged to the lower reaches of Tarim River in the past three decade years, the riparian forests degrade severely. The groundwater table, the saline content of the groundwater, as well as the content of free proline, soluble sugars, plant endogenous hormones (abscisic acid (ABA), and cytokinins (CTK)) of the leaves and relative rates of sap flow of the Populus euphratica Oliv. (arbor species), Tamarix ramosissima Ldb. (bush species), and Apocynum venetum L. (herb species) were monitored and analyzed at the lower reaches of the Tarim River in the study area where five positions on a transect were fixed at 100 m intervals along a sampling direction from riverbank to the sand dunes before and after water release. The physiological responses and acclimation strategies of three species to variations in water and salinity stress were discussed. It was found that A. venetum population recovered to groundwater table ranging from −1.73 to −3.56 m, and when exposed to saline content of the groundwater ranging from 36.59 to 93.48 m mol/L; P. euphratica appeared to be more sensitive to the elevation of groundwater table than the A. venetum and T. ramosissima at groundwater table ranging from −5.08 to −5.80 m, and when exposed to saline content of the groundwater ranging from 42.17 to 49.55 m mol/L. T. ramosissima tended to be the best candidate species for reclamation in this hyper-arid area because it responded to groundwater table ranging from −1.73 to −7.05 m, and when exposed to saline content of the groundwater ranging from 36.59 to 93.48 m mol/L. These results explained the distribution patterns of desert vegetation in the lower reaches of the Tarim River. Understanding the relationships among ecological factors variables, physiological response and acclimation strategies of plant individuals could provide guidance to sustainable management, reclamation and development of this and similar regions.     

Growth of Prosopis juliflora on pegmatite tailings from Nellore Mica Belt, Andhra Pradesh, India

 Prosopis juliflora was found to be occurring extensively on the pegmatitic tailings. Leaves and twigs of P. juliflora and soil samples were analyzed for mineral elements. The analysis has shown variation in the absorption and accumulation of mineral elements of the same plant species growing at different areas. The plant species accumulated large concentrations of Sr, B, and Ba. The ubiquitous thorny shrub P. juliflora has an extraordinary ecologic amplitude and tolerance for a variety of elements. Received: 10 October 1997 · Accepted: 13 January 1998     

Spatial and seasonal variation of salt ions under the influence of halophytes,in a coastal flat in eastern China

The high salinity of coastal saline field is a key factor limiting the reclamation. Halophytes have been utilized in the reclamation of saline land. The study area is in Yancheng, China. An analysis of the concentrations of Rb, Cs, Sr, and Ba, the ratio of Rb/Cs, and Sr/Ba in soils in autumn shows that the soil of this study area has great homogeneity. Artemisia halodendron, Gossypium hirsutum, and Sesbania cannabina were selected as the reclamation plants in the present study. In order to know the spatial-temporal distribution of soil salinity, the influence of plant-specific vegetation, and the difference of desalination among these halophytes in coastal flat, the authors analyze the soil-layers and seasonal variation in salt ions. Sodium chloride was accumulated in 0–5 cm topsoil with no vegetation during the winter and spring. The effect of desalinization of halophytes is significant. Of the three plant species, Sesbania cannabina has the greatest desalinization. The difference of ions composition of soils covered with various plant species is significant. It can be concluded that halophytes have better amelioration of coastal soil salinity. Special attention should be paid to the selection of plant species and measures to plant and cultivate crops in the reclamation of saline land.