共查询到20条相似文献，搜索用时 46 毫秒
1.
2.
位于河南省舞阳县的贾湖遗址是一处著名的新石器时代遗址,距今7800～9000年。遗址中出土了大量的人和动物的骨骼与牙齿,这为研究史前时期中国中部地区人类的迁移情况提供了很好的材料。在本次研究中,共分析了26个人和动物样品,包括12个人体骨密质样品、9个人牙釉质样品和5个猪牙釉质样品。测定了每个样品的锶同位素浓度和87Sr/86Sr比值,结果表明猪牙釉质的锶同位素浓度（平均值为196±51ppm,n=5,1σ）高于人牙釉质的浓度（平均值为110±61ppm,n=9,1σ）,人骨骼的锶同位素浓度（平均值为444±173ppm,n=12,1σ）明显地高于人牙釉质的浓度。根据5个猪牙釉质样品87Sr/86Sr平均值±2倍的标准偏差确定的当地锶同位素比值范围（0.712205～0.712420）,发现14个人类个体中有5个是外来迁入的,并且从第1期到第3期人口的迁移率有增加的趋势。这是在国内首次利用锶位素分析方法对古人类的迁移现象进行研究,同时也表明此方法可以很好地判断古人类迁移行为。 相似文献
3.
In order to ameliorate acidic discharge, the inactive Omega Coal Mine, West Virginia was partially filled by injection of a grout consisting of 98% coal utilization byproducts (CUB), including fluidized bed combustion ash and fly ash, and 2% Portland cement. In this study, discharge chemistry and Sr isotope ratios were determined to identify and quantify the extent of interaction between mine waters and the CUB–cement grout. Eight sampling sites were monitored around the downdip perimeter of the mine. The major and trace element chemistry of the discharges was generally not sufficient to distinguish between discharges that interacted with grout and those that did not. Elements that showed the most separation include K and As, which were elevated in some waters that interacted with CUB–cement grout. In contrast, the Sr isotope ratios clearly distinguished discharges from grouted and non-grouted areas. Discharges that bypassed the grouted portions had 87Sr/86Sr ratios ranging from 0.71510 to 0.71594, while two discharges that interacted with grout had ratios in the range of 0.71401–0.71456. The Treatment Inlet, which includes both grouted and ungrouted discharges, yielded intermediate isotopic ratios. Leaching experiments on CUB–cement grout, coal and surrounding rocks are consistent with the isotopic trends observed in the discharges. Based on these results, waters that interacted with grout received 30–40% of their Sr from the CUB–cement grout material. These results suggest that the grout material is chemically eroding at a rate of approximately 0.04% per year. This novel application of the Sr isotope system illustrates its ability to sensitively track and quantify fluid interaction with coal and CUB-based grout. 相似文献
4.
河南卢氏县拐峪绿松石采矿遗址位于伊洛盆地西缘,该遗址的发现为研究中原早期绿松石的来源提供了重要的考古学信息。为判定该古矿产出绿松石的流向,尝试利用热电离质谱仪(TIMS)检测了拐峪古矿绿松石样品的Sr、Pb同位素组成,并结合秦岭5个主要绿松石矿的相关同位素数据,尝试寻找其产地特征。分析结果显示,拐峪绿松石87Sr/86Sr值相对较高,整体大于0.719 0,高于其他产地,可视为其产地特征之一;采用208Pb/204Pb-207Pb/208Pb联合示踪可得到较好的结果,在相关图解中拐峪绿松石具有独立的数据聚集区,可作为判断其产地证据之一;采用208Pb/204Pb-87Sr/86Sr和207Pb/208Pb-87Sr/86Sr联合示踪,也得到了较好的判别效果,拐峪绿松石与其他产地界线清... 相似文献
5.
Yingfeng Xu 《Geochimica et cosmochimica acta》2004,68(12):2649-2657
Sequential extractions were performed on small amounts of particulate and sediment samples (6 to10 mg) from the Mississippi River mixing zone. The leachates were analyzed for Sr concentration and 87Sr/86Sr isotope ratio. Mn and Fe contents were also measured as their oxyhydroxides are potential carrier phases for Sr. The largest fraction of Sr in the solid phase (particulates and sediments) was found to be present in the residual, refractory fraction (>70% of total). By comparison with the corresponding sediment, particulates appear to have higher concentrations of nonresidual, labile Sr (30% vs. 15%). Carbonate components seem to play an important role as carriers for labile Sr in particulates and sediments. Changes in the composition and content of the solid phase may significantly modify both the 87Sr/86Sr isotope ratio of the total labile fractions and that of the bulk components. However, such modifications, under normal conditions, exert little measurable influence on the Sr isotope composition of the dissolved phase. 相似文献
6.
Biosphere Sr isotope composition data from Iceland and Scotland suggest that terrestrially feeding birds from these two countries will have significantly different 87Sr/86Sr isotope composition in their tissues. The aim of this study is to test if these differences can be measured within the bone and feather of migratory wading birds, who feed terrestrially as juveniles, thus providing a provenance tool for these birds. 相似文献
7.
对赛利普地区新生代火山岩Sr,Nd,Pb同位素资料分析,揭示了赛利普新生代火山岩同位素组成在时代和岩石组合上存在的规律性变化.总体上,随时代变新,Sr,Pb同位素呈递增,Nd同位素呈递减趋势,火山岩中地壳物质贡献明显增加.本区新生代火山岩与青藏高原北部(班公湖-怒江缝合带以北)相比,Sr,Nd和Pb同位素组成存在一定差异,尤其是新近纪以来钾质火山岩显著高87Sr/86Sr、极低143Nd/144Nd值,208Pb/204Pb值普遍偏高,古近纪火山岩这种差别则不明显.揭示了新生代以来,在印度大陆岩石圈向北俯冲过程中,拉萨地块比青藏高原北部融入了更多喜马拉雅大陆地壳端元成分.中新世早中期,印度大陆板块向北A型俯冲到拉萨地块基底西段,并发生岩石圈不同层次部分熔融、岩石圈断离等作用. 相似文献
8.
Omai is a high tonnage, low-grade, world-class gold deposit located in the Paleoproterozoic Guiana Shield. It is the second
most important gold deposit in the Guiana Shield (after Las Cristinas, Venezuela), and one of the largest in South America
(4.0 million oz.). Sm-Nd and Sr isotope data are presented for host rocks and for scheelite from auriferous quartz-carbonate-scheelite-sulfide-telluride
veins from the Omai deposit. Gold-bearing veins are hosted by the Paleoproterozoic Barama-Mazaruni Supergroup, a greenstone
belt sequence consisting of mafic volcanic rocks interbedded with sedimentary rocks that are intruded by quartz-feldspar porphyry
and rhyolite dikes. This lithologic sequence was folded and metamorphosed to lower greenschist facies during the Paleoproterozoic
Trans-Amazonian orogeny. The volcano-sedimentary unit was intruded by a post-tectonic quartz monzodiorite-diorite-hornblendite
stock. Initial Nd isotope ratios for the Omai volcanic rocks range from ɛNd=+2.1 to +4.2. These values suggest that this part of the Guiana Shield was a site of new crust formation during the Paleoproterozoic
and was not contaminated by older (Archean), reworked continental crust. Initial Nd isotope ratios for the Omai stock range
between +0.5 and +2.3, which suggest limited contamination with previously formed continental crust. Although the Nd isotopic
ratios of gold-related scheelites overlap with those of the host rocks, particularly the tholeiitic basalts at the interpreted
time of vein emplacement, the lack of both isotopic mixing and significant Nd movement during the hydrothermal process suggest
that the Nd isotope composition can be used to determine the isotopic characteristics of the ore fluid source area. At Omai,
the ore fluid is largely derived from a radiogenic Nd source, represented by mantle or lower crustal reservoirs. Strontium
isotope ratios for the scheelites cluster tightly between 0.7019 and 0.7021. The Sr isotope data suggest that unlike Nd, Sr
was significantly mobile during the hydrothermal process. The fluids responsible for the Omai deposit may have picked up Sr
along the flow path. The constant low Sr isotope values of scheelites probably reflect the key role that the local tholeiitic
basalts played as the main source of Sr in the fluids. Whereas Nd isotopes identify the fluid source area, the Sr isotopes
map the fluid flow paths.
Received: 11 February 1999 / Accepted: 1 November 1999 相似文献
9.
The 2nd century A.D. Roman annexation of the Nabataean Kingdom may have resulted in significant settlement disruption. Here we investigate the possibility that political refugees occupied Khirbet edh‐Dharih after Roman takeover, using strontium isotope analysis of archaeological human dental enamel. We additionally discuss regional patterning of 87Sr/86Sr in western Jordan based on archaeological faunal dental enamel samples to understand strontium isotope spatial heterogeneity and to facilitate interpretation of the Dharih results. Strontium isotope analysis of small mammal dentition varied as expected based on bedrock geology, but small faunal sample sizes did not accurately reflect the broad range of biologically available strontium at Dharih. Only one person at Khirbet edh‐Dharh appears to be non‐local based on isotopic data. The status of the remaining individuals is unclear, as they could have originated from Dharih or the Nabataean capital city of Petra. Incorporating modern fauna and soil samples to establish the local value may assist in characterizing the local strontium in a geologically complex area such as Dharih. Futhermore, future analysis of elemental strontium to assess dietary composition and diagenetic contamination would facilitate interpretation of the strontium sources in the Dharih individuals. © 2008 Wiley Periodicals, Inc. 相似文献
10.
Strontium isotopes and other geochemical signatures are used to determine the relationships between CO2-rich thermal (Chaves: 76 °C) and mineral (Vilarelho da Raia, Vidago and Pedras Salgadas: 17 °C) waters discharging along one of the major NNE–SSW trending faults in the northern part of mainland Portugal. The regional geology consists of Hercynian granites (syn-tectonic-310 Ma and post-tectonic-290 Ma) intruding Silurian metasediments (quartzites, phyllites and carbonaceous slates). Thermal and mineral waters have 87Sr/86Sr isotopic ratios between 0.716713 and 0.728035. 87Sr/86Sr vs. 1/Sr define three end-members (Vilarelho da Raia/Chaves, Vidago and Pedras Salgadas thermal and mineral waters) trending from rainfall composition towards that of the CO2-rich thermal and mineral waters, indicating different underground flow paths. Local granitic rocks have 87Sr/86Sr ratios of 0.735697–0.789683. There is no indication that equilibrium was reached between the CO2-rich thermal and mineral waters and the granitic rocks. The mean 87Sr/86Sr ratio of the thermal and mineral waters (0.722419) is similar to the Sr isotopic ratios of the plagioclases of the granitic rocks (0.71261–0.72087). The spatial distribution of Sr isotope and geochemical signatures of waters and the host rocks suggests that the thermal and mineral waters circulate in similar but not the same hydrogeological system. Results from this study could be used to evaluate the applicability of this isotope approach in other hydrogeologic investigations. 相似文献
11.
Identifying the geographic origins of Chinese mitten crabs is important for food safety and fair market competition. In this study, we used strontium (Sr) isotopes as a tool to trace the geographic origins of Chinese mitten crabs. Chinese mitten crabs, water, and different types of crab feed were collected from four different lakes for Sr isotope analyses. The results showed that the Sr isotope compositions of the different parts from one single crab were consistent within error, indicating that any piece of a crab could be used to represent the Sr isotope characteristics of the whole crab. The Sr isotope compositions of Chinese mitten crabs from the same lake were consistent within the analytical error, and the values were similar to the Sr isotope composition of the water from the same lake. However, the Sr isotope compositions of water and crabs from different lakes are significantly different. Therefore, the Sr isotope compositions of Chinese mitten crabs are mainly controlled by lake water composition, while the impact of feed is limited. This study provides an effective method for tracing the geographic origins of Chinese mitten crabs.
相似文献12.
通过动物骨的稳定同位素(C、N)分析,揭示家养动物的饲养模式及对先民肉食资源的贡献,是动物考古研究的重要组成之一.关中地区,是庙底沟文化(约5500年前)的主要核心分布区域之一.目前,对该地区和该时间段内家养动物的饲养模式及对先民肉食资源的贡献,尚缺乏足够的认识.为此,本文对陕西兴乐坊遗址出土动物与人骨开展了C、N稳定同位素分析,并对其中4个猪骨进行AMS-14C测年.同位素数据结果显示:野生动物(獐、青羊、梅花鹿)栖息于C3类的植被环境,家养动物(猪、狗)和人,则主要以C4类为食.3个猪个体的年代为5449~5300 cal.B.P.,而1个猪个体年代偏晚(4089~3985 cal.B.P.),其同位素数据也异于其他个体.结合该遗址的植物考古资料(粟和黍具有高的出土概率),认为:家养动物(猪和狗)饲喂了大量以粟类作物的副产品或者人类的残羹冷炙(粪便).根据食物链从生产者至消费者的同位素分馏效应(δ13 C值约富集1‰,δ15N值约富集3‰~5‰),比较了先民与野生动物以及家养动物的同位素数据,发现先民与猪的δ13 C和 δ15N值的差异最小(0.2‰和1.9‰),这反映了先民的肉食资源应主要源于家猪.家猪的饲养和管理,为庙底沟文化的快速发展奠定了深厚的物质和经济基础.此外,1例梅花鹿角具有偏正的δ13C值(-13.2‰),暗示发达的粟作农业还为先民尝试驯养其他野生动物(如鹿)提供了可能. 相似文献
13.
George D. Kamenov Mark Brenner Jaimie L. Tucker 《Geochimica et cosmochimica acta》2009,73(12):3549-3567
Analysis of a well-dated peat core from Blue Cypress Marsh (BCM) provides a detailed record of natural and anthropogenic factors that controlled the geochemical cycles of a number of trace elements in Florida over the last five centuries. The trace elements were divided into “natural” and “anthropogenic” groups using concentration trends from the bottom to the top of the core. The “natural” group includes Li, Sc, Cr, Co, Ga, Ge, Zr, Nb, Cs, Ba, Hf, Y, Ta, Th, and REE (Rare Earth Elements). These elements show similar concentrations throughout the core, indicating that changes in human activities after European arrival in the “New World” did not affect their geochemical cycles. The “anthropogenic” group includes Pb, Cu, Zn, V, Sb, Sn, Bi, and Cd. Upcore enrichment of these elements indicates enhancement by anthropogenic activities. From the early 1500s to present, fluxes of the “anthropogenic” metals to the marsh increased significantly, with modern accumulation rates several-fold (e.g., V) to hundreds of times (e.g., Zn) greater than pre-colonial rates. The dominant input mechanism for trace elements from both groups to the marsh has been atmospheric deposition. Atmospheric input of a number of the elements, including the anthropogenic metals, was dominated by local sources during the last century. For several elements, long-distant transport may be important. For instance, REE and Nd isotopes provide evidence for long-range atmospheric transport dominated by Saharan dust.The greatest increase in flux of the “anthropogenic” metals occurred during the 20th century and was caused by changes in the chemical composition of atmospheric deposition entering the marsh. Increased atmospheric inputs were a consequence of several anthropogenic activities, including fossil fuel combustion (coal and oil), agricultural activities, and quarrying and mining operations. Pb and V exhibit similar trends, with peak accumulation rates in 1970. The principal anthropogenic source of V is oil combustion. The decline in V accumulation after 1970 in the BCM peat corresponds to the introduction of low-sulfur fuels and the change from heavy to distilled oils since the 1970s. After the 1920s, Pb distribution in the peat follows closely the history of alkyl lead consumption in the US, which peaked in the 1970s. Pb isotopes support this inference and furthermore, record changes in the ore sources used to produce leaded gasoline. Idaho ores dominated the peat Pb isotope record until the 1960s, followed by Pb from Mississippi Valley Type deposits from the 1960s to the 1980s. Enhanced fluxes of Cu, Zn, Cd, Sn, Sb, Bi, and to some extent Ni during the last century are likely also related to fossil fuel combustion. Local agricultural activities may also have influenced the geochemical cycles of Cu and Zn. The peat record shows enhanced U accumulation during the last century, possibly related to phosphate mining in western Florida. Sr isotopes in the peat core also reflect anthropogenic influence. The 87Sr/86Sr ratio decreases from natural background values in the basal part of the core to lower values in the upper part of the core. The Sr isotope shift is probably related to quarrying operations in Florida, and marks the first time an anthropogenic signal has been detected using the Sr isotope record in a peat core. 相似文献
14.
M.H. Dodson 《Lithos》1982,15(3):215-219
A general null hypothesis for isotope geochemistry states that the isotopic composition of an element is independent of its concentration or any other geochemical property of the population. ‘Spurious’ correlations between the ratios 87Sr/86Sr and 87Rb/86Sr (orRb/Sr), due to the common denominator effect, may be ruled out because they contradict this null hypothesis. Mixing processes may be regarded as geochemical counterparts of the common denominator effect. In geochronological systems which satisfy the basic assumptions of the Rb-Sr isochron method observed correlations between Sr isotope abundance and Sr concentration must be secondary to the direct causal dependence of 87Sr/86Sr upon Rb/Sr ratios. 相似文献
15.
Strontium isotope analysis of tooth enamel is a useful provenancing technique to investigate the childhood origins and residential mobility of ancient people. However, where different geographical target regions have similar biosphere 87Sr/86Sr it is often difficult to resolve the 87Sr/86Sr ranges of two different groups of people and establish what constitutes the local range at each site. Here a multi-period study is presented from the Outer Hebrides, Scotland and an investigation of Neolithic and Early Bronze Age populations from the Yorkshire Wolds, NE England. The aim is to demonstrate that, despite complex human dietary strategies, simple mixing systems with only two end-members do occur in archaeological human populations in certain geological provinces and, despite overlapping 87Sr/86Sr ranges, it is possible to separate two populations based on the structure within the data set. 相似文献
16.
《Chemical Geology》2002,182(2-4):203-225
Accessory gangue scheelite (CaWO4) from the Archaean Mt. Charlotte lode Au deposit can be divided into two types with different rare earth element (REE) signatures. In some scheelite grains, specific REE signatures are reflected by different cathodoluminescence colours, which can be used to map their often complex oscillatory intergrowths. Domains with specific REE contents from two grains were sampled for Sm/Nd, Rb/Sr and Pb isotopic analyses using a micro-drilling technique.Type I scheelite is strongly enriched in middle REE (MREE) and Eu anomalies are either absent or slightly positive. Four fragments collected from Type I regions of two crystals have initial 87Sr/86Sr and εNd values ranging from 0.70141 to 0.70163 and +2.5 to +3.5, respectively, and Pb isotope ratios reflecting the composition of greenstone sequence. This may indicate that Nd and Pb have their source, either locally or regionally, in the greenstones. Basic greenstone lithologies have 87Sr/86Sr<0.7015, and the radiogenic Sr signatures indicate that part of the Sr originated from felsic lithologies located either within or beneath the host greenstone pile. Alternatively, the Sr signature may have evolved from preferential leaching of a Rb-rich mineral during hydrothermal alteration of the greenstone.The REE patterns of Type II scheelite are either flat or MREE-depleted and have strong positive Eu anomalies. Three fragments collected from Type II regions of the same two crystals have initial 87Sr/86Sr ratios and εNd values between 0.70130 and 0.70146, and +1.1 to +2.6, respectively, and Pb isotope signatures that are once again similar to that of the greenstone. This implies that 87Sr/86Sr ratios in Type II fluids were closer to those of the host dolerite (0.7008–0.7013), due to more extensive fluid interaction with the dolerite.A positive correlation between Na and REE suggests that REE3+ are accommodated by the coupled substitution REE3++Na+=2 Ca2+ into both Type I and Type II scheelite. This is consistent with a fractional crystallisation model to explain the change in REE patterns from Type I to Type II, but not with a model involving different coupled substitutions and fluids from different origins. We propose that the complex REE and isotopic signatures of scheelite at Mt. Charlotte are related to small (<m) to medium (<km) scale processes involving mixing between “fresh” batches of hydrothermal fluid with fluids that had already been involved in extensive wall-rock alteration.The very high-εNd values measured in some scheelites have been previously used to link gold mineralisation with komatiites containing unusually high Sm/Nd ratios. However, tiny (<20 μm) grains of secondary hydroxyl-bastnäsite were found within micro-fractures of one scheelite grain containing an extremely high-εNd signature. The hydroxyl-bastnäsite probably formed during recent REE redistribution within the scheelite as a result of meteoric fluid circulation. The scale of this cryptic low-temperature alteration is sufficient to explain the anomalously high-εNdi values observed in scheelite from Western Australia. 相似文献
17.
《Applied Geochemistry》2005,20(4):749-766
A synthesis of Sr isotope data from shallow and deep groundwaters, and brines from the Fennoscandian and Canadian Shields is presented. A salinity gradient is evident in the water with concentrations varying from approximately 1–75 g L−1 below 1500 m depth in the Fennoscandian Shield and from 10 up to 300 g L−1 below 650 m depth in the Canadian Shield. Strontium isotope ratios were measured to assess the origin of the salinity and evaluate the degree of water–rock interaction in the systems. In both shields, the Sr concentrations are enriched relative to Cl, defining a positive trend parallel to the seawater dilution line and indicative of Sr addition through weathering processes. The depth distribution for Sr concentration increases strongly with increasing depth in both shields although the variation in Sr-isotope composition does not mirror that of Sr concentrations. Strontium-isotope compositions are presented for surface waters, and groundwaters in several sites in the Fennoscandian and Canadian Shields. Numerous mixing lines can be drawn reflecting water–rock interaction. A series of calculated lines links the surface end-members (surface water and shallow groundwater) and the deep brines; these mixing lines define a range of 87Sr/86Sr ratios for the deep brines in different selected sites. All sites show a specific 87Sr/86Sr signature and the occurrence of large 87Sr/86Sr variations is site specific in both shields. In Canadian Shield brines, the Sr isotope ratios clearly highlight large water rock interaction that increases the 87Sr/86Sr ratio from water that could have been of marine origin. In contrast to the Canadian Shield, groundwater does not occur in closed pockets in the Fennoscandian, and the well-constrained 87Sr/86Sr signatures in deep brines should correspond to a large, well-mixed and homogeneous water reservoir, whose Sr isotope signature results from water–rock interaction. 相似文献
18.
In this paper we report the Sr isotope signatures, and Sr, Al and Na concentrations of 30 surface waters (lakes/ponds and rivers/creeks) and 19 soil sample extracts from the island of Bornholm (Denmark) and present a categorized 87Sr/86Sr value distribution map that may serve as a base for provenance studies, including archaeological migration and authenticity proof for particular food products. The Sr isotopic compositions of surface waters range from 87Sr/86Sr = 0.7097–0.7281 (average 0.7175 ± 0.0049; 1σ), whereas 0.1 M HNO3, 0.05 M HNO3, and 0.01 M CaCl2 soil extracts range from 87Sr/86Sr = 0.7095–0.7197 and define somewhat lower but statistically indistinguishable averages of 0.7125 ± 0.003 (1s). These compositions are lower than the values expected from the Precambrian granitoid basement (87Sr/86Sr = 0.758–0.944), and from the overlying, mainly clastic Paleozoic sediments. Combined Sr isotope composition vs. Sr, Na and Al concentration relationships of soil extracts imply that lowering of the isotopic composition of leachable Sr on Bornholm results as a consequence of significant admixture to this fraction of Sr deposited as marine salts (aerosols), and that rainwater only has a minor influence on the Sr budget of the surface waters. Positively correlated Al/Na and [1/Sr] vs. 87Sr/86Sr relationships in soil extracts and surface waters indicate that the surface run-off on Bornholm is characterized by two predominant sources, namely marine aerosols (sea salts) with high Sr and low 87Sr/86Sr values, and a source with lower [Sr] delivering radiogenic Sr to the surface waters, which we equate with Sr leached from the products of mineral weathering (soils).A feasibility study for using Sr isotopic compositions of surface waters and soil extracts as a proxy for bioavailable Sr signatures was performed with a few samples collected in the vicinity of the eleventh century AD Ndr. Grødbygård cemetery site in SW Bornholm, from where Sr isotope compositions of modern fauna samples and tooth enamel of humans buried in the cemetery have been reported. Waters and soil extracts studied herein from around this site range from 87Sr/86Sr = 0.7104–0.7166 and correspond to Sr compositions extracted from snail shells in this area which span a range of 87Sr/86Sr = 0.7095–0.7160. Some human tooth enamel is characterized by more radiogenic values (87Sr/86Sr up to 0.718) which points to a possible provenance of these humans from the granite–gneiss terrain in the north of the island and/or to immigration of these humans in their childhood from other places (for example from mainland Sweden) to Bornholm. If the total compositional range of 87Sr/86Sr = 0.709–0.718 (n = 44) recorded in human enamel from the Ndr. Grødbygård site is considered representative for the variation of bioavailable Sr on Bornholm, then our soil leachate and surface water data entirely covers this range. We therefore propose that the combination of Sr isotope analyses of surface waters and soil leachates are an easy, fast and relatively cost efficient way to characterize a local bioavailable 87Sr/86Sr signature, and consequently propose that the overall average of 87Sr/86Sr = 0.7153 ± 0.0048 (1σ; n = 50) can be taken as a band for bioavailable Sr fractions suitable to discriminate between local and non-local signatures in provenance studies in the field of archaeology and for food and plant authenticity control in agricultural applications. 相似文献
19.
Isotope Tracing and Prospecting Assessment of Gold-Silver Deposits in Zhejiang Province 总被引：1，自引：0，他引：1
Chen Haoshou Xu Butai Department of Earth Sciences Zhejiang University Hangzhou Zhejiang Zhejiang Institute of Geology Mineral Resources Hangzhou Zhejiang Liu Xinzhu 《《地质学报》英文版》1997,71(3):293-304
Three different types of gold and silver deposits in Zhejiang Province(Huangshan gold deposit, Zhilingtou gold-silver deposit and Haoshi silver deposit) showmarked differences in lead and strontium isotopic composition, suggesting three differentsources and geneses of these deposits. The Huangshan gold deposit features low initial Srisotope ratios and low μ values or low content of radiogenic Pb and its ore-forming materialscame primarily from the upper mantle; the Zhilingtou gold-silver deposit shows high initial Srisotope ratios and high μ values or high content of radiogenic Pb and the ore-forming materialswere derived mainly from the upper crust; and the Haoshi silver deposit has its Pb and Srisotope ratios between the above two cases with the ore-forming materials stemming from boththe mantle and the crust. The characteristic Pb isotopic composition may serve as an indicatorfor prospecting for different types of ore deposits. 相似文献
20.
Anselm Loges Thomas Wagner Thomas Kirnbauer Susanne Göb Michael Bau Zsolt Berner Gregor Markl 《Applied Geochemistry》2012
Thermal water samples and related young and fossil mineralization from a geothermal system at the northern margin of the Upper Rhine Graben have been investigated by combining hydrochemistry with stable and Sr isotope geochemistry. Actively discharging thermal springs and mineralization are present in a structural zone that extends over at least 60 km along strike, with two of the main centers of hydrothermal activity being Wiesbaden and Bad Nauheim. This setting provides the rare opportunity to link the chemistry and isotopic signatures of modern thermal waters directly with fossil mineralization dating back to at least 500–800 ka. The fossil thermal spring mineralization can be classified into two major types: barite-(pyrite) fracture filling associated with laterally-extensive silicification; and barite, goethite and silica impregnation mineralization in Tertiary sediments. Additionally, carbonatic sinters occur around active springs. Strontium isotope and trace element data suggest that mixing of a hot (>100 °C), deep-sourced thermal water with cooler groundwater from shallow aquifers is responsible for present-day thermal spring discharge and fossil mineralization. The correlation between both Sr and S isotope ratios and the elevation of the barite mineralization relative to the present-day water table in Wiesbaden is explained by mixing of deep-sourced thermal water having high 87Sr/86Sr and low δ34S with shallow groundwater of lower 87Sr/86Sr and higher δ34S. The Sr isotope data demonstrate that the hot thermal waters originate from an aquifer in the Variscan crystalline basement at depths of 3–5 km. The S isotope data show that impregnation-type mineralization is strongly influenced by mixing with SO4 that has high δ34S values. The fracture style mineralization formed by cooling of the thermal waters, whereas impregnation-type mineralization precipitated by mixing with SO4-rich groundwater percolating through the sediments. 相似文献