Initial 87Sr/86Sr ratios of plutonic rocks from Japan

Initial ⁸⁷Sr/⁸⁶Sr rations were determined for more than 80 plutonic rocks in Japan. The ⁸⁷Sr/⁸⁶Sr ratios of gabbroic and granitic rocks show no significant difference in plutonic terranes where both rocks occur closely associated, implying a genetic relationship between them (e.g., Green Tuff belt) or reequilibration at deep level (e.g., Ryoke belt). Wherever granitic rocks occur independently from gabbroic rocks, the granites have higher ratios than the gabbros.Initial ⁸⁷Sr/⁸⁶Sr ratios of the granitic rocks are low (<0.706) in Northeast Japan but high (<0.706) in Southwest Japan, the boundary being the Tanakura Tectonic Line. Within Southwest Japan, the ratios are low along the Japan Sea side of the southernmost area. This regional variation is generally correlated with thickness of the continental crust as deduced from the Bouguer anomaly.Initial ⁸⁷Sr/⁸⁶Sr ratios of the granitic rocks vary from 0.7037 to 0.7124. The low group (<0.706) is considered to consist of essentially mantle-derived magmas contaminated by crustal material in lesser but varying degree, because of its geological setting and initial ⁸⁷Sr/⁸⁶Sr values. The high group may have been formed by contamination of a deep-seated magmas by crustal material or by generation of the main part of the magmas within the continental crust. The ratios of individual belts reflect their own history depending upon age and Rb/Sr ratio of the crustal material.Initial ⁸⁷Sr/⁸⁶Sr ratios of granitic rocks are generally low for the magnetite-series but high for the ilmenite-series. Thus, a negative correlation is observed between initial ratios and ³⁴S for most Cretaceous-Paleogene granites. However, Neogene ilmenite-series granites are low in both initial ⁸⁷Sr/⁸⁶Sr and ³⁴S indicating interaction of the granitic magma with young sedimentary rocks enriched in ³²S.     

桂林地区岩溶水87Sr/86Sr特征

锶是岩石圈上部含量最大的微量元素，其元素及其同位素化学性质都比较稳定。不同水岩作用条件下，锶元素含量及其同位素值都不一样。本文通过对桂林地区的两个典型岩溶地下河系统不同类型地下水样87Sr/86Sr值和Sr含量的分析，得出；流经不同岩层的地下水其87Sr/86Sr值和Sr含量不同，同一地下河系统中不同类型地下水的87Sr/86Sr值Sr含量不同，其值的差异由岩性和水岩作用决定。说明87Sr/86Sr值能反映地下水的形成、径流和混合作用，是较理想的示踪剂，在岩溶水研究中具有很广阔的应用前景。     

埋藏后生作用对生物壳体87Sr/86Sr的影响研究

根据小渡口剖面２８层有孔虫、介形虫、腹足类生物壳体的微观观察、微量元素及其比值、＾８７Ｓｒ／＾８６Ｓｒ与微量元素特征对比经及水－岩反应＾８７Ｓｒ／＾８６Ｓｒ的混合模式,显示生物壳体遭受了埋藏后生作用,但对生物壳体原始的＾８７Ｓｒ／＾８６Ｓｒ比值基本没有改变或影响甚微,推测参与埋藏后生作用的流体与生物壳体具有相近的Ｓｒ同位素组成或较悬殊的Ｓｒ含量。同时,实际研究表明评价和判别埋藏后生作用对生物壳体原     

87Sr/86Sr ratios in Permo-Carboniferous sea water from the analyses of well-preserved brachiopod shells

Sr isotopic analyses of well-preserved portions of Permo-Carboniferous brachiopods distributed globally confirm the general shape of the Sr isotope age curve established by previous workers for this time interval. There is little variation between the Sr isotopic composition of unaltered portions of brachiopods and that of portions of the same shell interpreted to be diagenetically altered (based on cathodoluminescence, elemental, and stable isotopic data). However, the Sr isotopic composition in diagenetically altered micritic matrix adjacent to the shell is more radiogenic. The Sr isotopic composition in the unaltered portions of calcitic megafossils has potential as a stratigraphie tool.     

On the interpretation of the oceanic variations in87Sr/86Sr as recorded in marine limestones

The present published inventory of fluvial Sr and⁸⁷Sr/⁸⁶Sr data, combined with new information from the big rivers of Eastern Siberia (a combined total of ∼ 1,000 measurements), is used to investigate the probable origin of the large rise in the marine isotopic ratio, recorded in limestones, over the last ∼ 20 million years. With the exception of the data from the Ganga-Brahmaputra all measurements fall on what is proposed to be called the “Wickman trend”, essentially a mixing line between the limestone sink for Sr, with the integrated marine ratio, and the flux from the weathering of average continental crust. However, time-variations along this trend, i.e. changes in relative weathering intensity, cannot explain the observations from limestones. They can only be caused by very high and radiogenic fluxes of Sr as are occurring from the present Himalayan orogeny, lying far above the Wickman trend and caused by metamorphic remobilization of radiogenic Sr during underthrusting and subsequent unroofing associated with the collision of India with Eurasia. In general the variations in the ratio are therefore caused by specific tectonic events, not by general climatic variations in the intensity of aluminosilicate weathering.     

Temporal Variation in Sr and 87Sr/86Sr of Yangtze River: An Example from Datong Hydrological Station

Temporal variation of dissolved ⁸⁷Sr/⁸⁶Sr in the Yangtze River is poorly understood compared to other Tibetan rivers. In this study, dissolved Sr and ⁸⁷Sr/⁸⁶Sr were measured from a temporal series of water samples collected biweekly at Datong Hydrological Station over a period of one year. Our results show that Sr concentration in the Yangtze River ranges from 1.74 to 2.92 μmol/L with ⁸⁷Sr/⁸⁶Sr of 0.710125 to 0.710965. The Sr concentration and ⁸⁷Sr/⁸⁶Sr shows a distinct seasonal variation, with a general increase in ⁸⁷Sr/⁸⁶Sr ratios from summer to winter and some fluctuations during July and December, then followed by a gradually decrease till the next rainy season. The seasonal variation results from the variation of contributions from different sub-basin due to the spatially and seasonally variable rainfall across the basin. During the flood season, more contribution from upper reach (low ⁸⁷Sr/⁸⁶Sr values) due to the strong rainfall decreases the ⁸⁷Sr/⁸⁶Sr ratio at lower reach. While the severe drought which happened in the middle-lower reaches (high ⁸⁷Sr/⁸⁶Sr values) from January to May explains the decrease in the later part of the data by the decrease of the contribution from middle-lower reaches. The discharge weighted annual ⁸⁷Sr/⁸⁶Sr and annual Sr flux of the Yangtze River based on the time series data are 0.710628 and 1.9×10⁹ mol/a, respectively. It was also indicated that dissolved ⁸⁷Sr/⁸⁶Sr in the Yangtze River is well correlated to the extreme climate events and might contribute to our explanation for reconstructing past climatic changes by using ⁸⁷Sr/⁸⁶Sr ratios of the sedimentary record in the delta .     

Petrogenetic Significance of Initial 87Sr/86Sr Ratios in the North Atlantic Tertiary Igneous Province in the Light of Rb-Sr, K-Ar and 18O-abundance Studies of the Sarqata qaqa Intrusive Complex Ubekendt Ejland, West Greenland

A single Rb-Sr whole rock ‘isochron’ from threegabbroic and six granitic samples from the Sarqâta qáqâComplex, Ubekendt Ejland, yields an age and initial ⁸⁷Sr/⁸⁶Srratio of 65±5 m.y. (ß = 1.47x10^-11 yr^-1) and0.7045±0.0003. K-Ar measurements on two biotite separatesfrom the gabbro give ages of 55.4±1.5 and 54.0±1.5m.y. Determinations of ¹⁶O/¹⁸O ratios in two gabbro and fourgranite samples yield average values of ±5.53±0.04and +6.74± 0.37% respectively, relative to SMOW. The following conclusions are drawn: 1. Since the balance of field evidence indicates that the graniteshortly post-dates the gabbro, the Rb-Sr and K-Ar ages mustbe highly discordant, rather than dating separate intrusiveevents. It is suggested that the Sarqâta qáqâComplex cooled very slowly (ca. 50–200 °C per m.y.). 2. The extrusion of the plateau basalts in West Greenland musthave occurred before 65 m.y. This appears to be slightly olderthan the Tertiary igneous activity in East Greenland, the Faeroes,NE Ireland, NW Scotland and Lundy; an age pattern which accordswith recent reconstructions of the formation of the North Atlantic. 3. The strontium and oxygen isotope data both support an hypothesisthat the Sarqâta qáqâ granite is comagmaticwith the mantle-derived basic lavas and plutonic rocks of UbekendtEjland. This in turn gives indirect support to recent suggestionsthat the Eocene granites of Skye, NW Scotland, may have a similarorigin and that their relative enrichment in ⁸⁷Sr may not indicategenesis by crustal melting in the aureoles of large basic plutons,but rather trace element equilibration with surrounding ⁸⁷Sr-richcountry rocks during an episode of influx of meteoric groundwater which has left them severely depleted in ¹⁸O.     

Normalized 87Sr86Sr by multiple collection and comparison to a standard

A system for precisely determining normalized ${}^{87}\text{Sr}{}^{86}\text{Sr}$ by comparing unknown to standard in a solid-source quadruple-collector mass spectrometer is outlined. This is made possible by a mathematical approximation in the data-reduction process.     

我国某些元古宙及早寒武世碳酸盐岩石的锶同位素组成

本文报道了我国某些元古宙及早寒武世碳酸盐岩石锶同位素的测量结果，样品采自蓟县中元古界和峡东震旦－寒武系标准剖面，共４６件样品５４个测定数据。样品分析分别在澳大利亚国立大学和宜昌地质矿产研究所同位素实验室进行。取得的测定数据经空白校正和年龄校正，给出样品形成时＾８７Ｓｒ／＾８６Ｓｒ的初始值，测定中用ＮＢＳ－９８７和ＮＢＳ－６０７标准物质监探仪器状态和分析过程，得到的＾８７Ｓｒ／＾８６Ｓｒ值的精度好于     

87Sr/86Sr isotope composition of bottled British mineral waters for environmental and forensic purposes

Mineral waters in Britain show a wide range of ⁸⁷Sr/⁸⁶Sr isotope compositions ranging between ⁸⁷Sr/⁸⁶Sr = 0.7059 from Carboniferous volcanic rock sources in Dunbartonshire, Scotland to ⁸⁷Sr/⁸⁶Sr = 0.7207 in the Dalradian aquifer of Aberdeenshire, Scotland. The ⁸⁷Sr/⁸⁶Sr composition of the waters shows a general correlation with the aquifer rocks, resulting in the waters from older rocks having a more radiogenic signature than those from younger rocks. This wide range of values means that the Sr isotope composition of mineral water has applications in a number of types of studies. In the modern commercial context, it provides a way of fingerprinting the various mineral waters and hence provides a method for recognising and reducing fraud. From an environmental perspective, it provides the first spatial distribution of bio-available ⁸⁷Sr/⁸⁶Sr in Britain that can be used in modern, historical and archaeological studies.     

87Sr/86Sr ratio: a natural tracer to monitor groundwater flow paths during artificial recharge in the Bangkok area, Thailand

The aquifer system in the Thon Buri sedimentary basin below the deltaic flood plain of the Chao Phraya River, central Thailand, has been exploited for public water supply for the capital Bangkok since the early 1920s. Groundwater withdrawal, currently 1.4 million m³/d, has resulted in a maximum decline in hydraulic head of up to 40 m. This has induced land subsidence of as much as 1.7 m (1940–1992) in the eastern suburbs of the metropolis. Artificial injection of purified water within an area-wide network of recharge wells could constitute a remedy to slow the water level depression within the sedimentary basin, and thus the subsidence. This requires a prior shutdown of water withdrawal. The flow paths of the injected water can be traced by changes in the ⁸⁷Sr/⁸⁶Sr ratio of the groundwater and injected water mixture within the three main aquifers in the basin that are used for public supply. The ratios, monitored at five monitoring stations within the cone of depression, have been constant over 3 years. Injection of the calculated cone volume of 5.2?×?10⁹ m³ would take at least 10 years, depending on the injection pressure and the number and position of wells.     

距今7Ma以来甘肃灵台剖面 Nd和 Sr同位素特征

测定了 7 Ma B.P.以来灵台剖面红粘土和黄土-古土壤序列的酸不溶物 Sr和 Nd同位素组成.样品酸不溶物 87Sr/86Sr变化可明显分为两个阶段.第一个阶段,从 7 Ma B.P.到 2.5 Ma B.P.,为红粘土层,酸不溶物 87Sr/86Sr稳定位于高值,反映了东亚冬季风处于相对平稳的弱势.第二个阶段,从 2.5 Ma B.P.到现在,酸不溶物 87Sr/86Sr呈下降趋势,波动加强,反映了东亚冬季风不断增强,并且冬季风和夏季风交替变化加强. 7 Ma B.P.以来灵台剖面红粘土和上覆的黄土-古土壤的 Nd同位素组成一致,并揭示 7 Ma B.P.以来,北太平洋中部沉积物与黄土高原黄土都来自相同的物源区.     

Ba/Sr,Ca/Sr and 87Sr/86Sr ratios in soil water and groundwater: implications for relative contributions to stream water discharge

Barium/Sr and Ca/Sr ratios have been used to model the relative importance of different sources of stream water. Major and trace element concentrations together with ⁸⁷Sr/⁸⁶Sr ratios were measured in precipitation, soil water, groundwater and stream water in a small (9.4 km²) catchment in northern Sweden. The study catchment is drained by a first order stream and mainly covered with podzolized Quaternary till of granitic composition. It is underlain by a 1.8 Ga granite. A model with mixing equations used in an iterative mode was developed in order to separate the stream water into 3 subsurface components: soil water, shallow groundwater, and deep groundwater. Contributions from precipitation are thus not included in the model. This source may be significant for the stream water generation, but it does not interfere with the calculations of the relative contributions from the subsurface components. The results show that the deep groundwater constitutes between 5 and 20% of the subsurface water discharge into the stream water. The highest values of the deep groundwater fraction occur during base flow. Soil water dominates during snowmelt seasons, whereas during base flow it is the least important fraction. Soil water accounts for 10–100% of the subsurface water discharge into the stream water. Shallow groundwater accounts for up to 80% of the subsurface water discharge with the lowest values at peak discharge during snowmelt seasons and the highest values during base flow. The validity of the model was tested by comparing the measured ⁸⁷Sr/⁸⁶Sr ratios in the stream water with the ⁸⁷Sr/⁸⁶Sr ratios predicted by the model. There was a systematic difference between the measured and modelled ⁸⁷Sr/⁸⁶Sr ratios which suggests that the fraction of soil water is overestimated by the model, especially during spring flood. As a consequence of this overestimation of soil water the amount of shallow groundwater is probably underestimated during this period. However, it is concluded that the differences between measured and predicted values are relatively small, and that element ratios are potentially effective tracers for different subsurface water flowpaths in catchments.     

古湖相碳酸盐沉积和化石贝壳的87Sr/86Sr及其意义

位于极端干旱区的额济纳盆地，是我国内陆地区代表性的盆地之一。这里不仅具有典型的大陆性气候、脆弱的生态系统，而且在平缓的戈壁滩下面，沉积有厚达200-400余米的古湖相地层。盆地东南与最高达近500m沙丘的巴丹吉林沙漠比邻，构成了特征性的盆地-沙漠系统，是世界少有的自然景观，也是目前研究热点之一。 考察研究工作揭示，巴丹吉林沙漠在蹑今30000a左右存在一湿润时期（Wunnemann等，1998；杨小平，2002；杨小平等，2003），并与临区腾格里沙漠相应时期发育的大湖期可以对比（Zhang等，2002，2004）。 新近的考察工作发现，在盆地东南部古日乃与巴丹吉林沙漠过渡区，存在有多级古沙丘被水夷平的、高度不等的平台，在这些平台之上，保存有水体快速蒸发环境条件下沙粒物质被钙质胶结的坚硬、类似砂岩的顶盖，其高度在大范围内可以对比，同时伴有湖相碳酸盐沉积、根管等。这些地貌、沉积与盆地北部沙砾石层中大量出现的贝壳化石和湖相地层，构成了古湖泊存在的地质证据。 14C测年结果表明，分布于第二级平台上的碳酸盐结核其形成年代为距今25000a前（25630±270a、25530±230a、25640±220a，半衰期5568a，下同），掰鳃类贝壳化石的年代为距今28000a(28530±430a、28630±320a、28780±340a、28560±280a)。 对这两组样品进行87Sr/86Sr分析结果表明（表1），碳酸盐沉积的87Sr/86Sr比值变化较为显著而贝壳化石的87Sr/86Sr比值变化相对较小，且贝壳化石的87Sr/86Sr比值的平均值小于碳酸盐沉积的87Sr/86Sr比值。 由于贝壳化石和碳酸盐沉积的87Sr/86Sr比值在一定意义上代表了古湖水的锶同位素比值，而87Sr/86Sr比值又与湖泊水体盐度相关（刘秀明等，2000），因此可以推测，贝壳化石所代表的古湖泊发育时期的水体较碳酸盐结核形成时期的盐度要低，也就是说古湖泊发育早期的为淡水，后期水体盐度有所增高。这是与贝壳化石本身代表的淡水种属相一致。由于后期湖泊水拉的快速下降和水体的快速蒸发，使得碳酸盐结核沉积的87Sr/86Sr比值增高，而这种古湖泊水位的快速下降和结核的形成是直接与气候变化相关联的。反映了该时期额济纳盆地古湖泊高湖面的存在和气候快速变化的历史。     

High-Precision Direct Determination of the ~(87)Sr/~(86)Sr Isotope Ratio of Bottled Sr-Rich Natural Mineral Drinking Water Using MC-ICP-MS

Strontium has four naturally occurring stable isotopes,84Sr,86Sr,87Sr,and 88Sr,with abundances of 0.56,9.87,approximately 7.04,and 82.53 atomic %,respectively.The 87Sr/86Sr isotope ratio is variable due to the addition of radiogenic 87Sr produced by the beta decay of 87Rb with a half-life of 4.88 ± 0.05 Ga.Thus,     

New Minimal 87Sr/86Sr Values in Permian Biogenic Carbonates of the Omolon Massif (Northeastern Asia)

Doklady Earth Sciences - For the first time very low values (up to 0.706707) of the ratio 87Sr/86Sr were recorded in the biogenic carbonates of the Omolon massif (Northeast Asia) of the Capitanian...     

87Sr/86Sr in kimberlitic carbonates by ion microprobe: Hydrothermal alteration,crustal contamination and relation to carbonatite

Carbonates in a 30 cm wide zoned kimberlite dyke from the De Beers Mine, Kimberley, S. Africa were studied by cathodoluminescence and electron microprobe techniques and their ⁸⁷Sr/⁸⁶Sr ratios were measured using an AEI-IM20 ion microprobe. Primary carbonates (including calcite dendrites, rhombohedral calcites in segregation vesicles and mosaic dolomite) have high Sr (0.69–1.35 wt.% SrO) and Ba (0.24–0.44% BaO) and ⁸⁷Sr/⁸⁶Sr ratios in the range 0.7046 to 0.7056. Secondary sparry calcite in amygdales and veins is characterised by low Ba (<0.05% BaO) and ⁸⁷Sr/⁸⁶Sr near 0.72. Rhombohedral calcite 0.5 cm from a contact with 2,900 my. old biotite-gneiss has minor element chemistry like that of primary carbonate, but an elevated ⁸⁷Sr/⁸⁶Sr ratio of 0.7103, possibly indicating crustal contamination in a boundary layer of the kimberlite magma. Amygdale-like segregations of carbonate and/or serpentine originated as gas-cavities and were not formed by liquid immiscibility. They are now filled either by secondary calcite or by minerals precipitated from residual kimberlite liquid. However, dendritic calcite and primary dolomite and calcite with high Sr, Ba and low ⁸⁷Sr/⁸⁶Sr demonstrate shared chemical characteristics between these carbonates and carbonatite. The primary kimberlite magma had initial ⁸⁷Sr/⁸⁶Sr close to 0.7046.     

Crustal contamination versus enriched mantle: 143Nd/144Nd and 87Sr/86Sr evidence from the Italian volcanics

¹⁴³Nd/¹⁴⁴Nd, ⁸⁷Sr/⁸⁶Sr, and REE analyses are presented on a wide variety of Pliocene-Recent volcanic rocks from central Italy. ¹⁴³Nd/¹⁴⁴Nd varies from 0.51214–0.51289 and ⁸⁷Sr/⁸⁶Sr from 0.7255-0.7036; while the rare earth elements are characterised by light RE enrichment and a significant negative Eu anomaly. These Italian volcanics are tentatively subdivided into three zones: (1) N. Tuscany where the magmas are believed to reflect crustal anatexis. (2) A central zone in which hybrid (crust/ mantle) rocks have been recognised. (3) A southern zone, south of Rome, where mantle-derived magmas are identified which have been largely unaffected by interaction with continental crust. At Roccamonfina, in zone 3, Rb/Sr and Sm/Nd pseudo isochrons are observed but since the calculated ages are 0.5 and 2.0 b.y. respectively it is argued that a simple isochron model is not applicable and that the data are most easily explained by a recent mixing event within the upper mantle. It is envisaged that this occurred during metasomatism of the upper mantle source region by a fluid that had high ⁸⁷Sr/⁸⁶Sr and low ¹⁴³Nd/¹⁴⁴Nd and was enriched in K, Rb, and LREE's but relatively depleted in Sr²⁺ and Eu²⁺.     

来源物质控制的黄土酸不溶相87Sr/86Sr

陈骏等^[1]在黄土-古土壤序列的表生地球化学过程研究中指出,由于矿物在化学风化过程中的行为存在差异,Sr同位素比值的高与低能从一定程度上反映沉积物的风化强度,并据此可用于恢复东亚夏季风强度变化历史。但作为一种粉尘堆积,黄土物质在其源区即已经历过风化作用^[2],因此其Sr同位素比值应同时受控于源区和沉积区的风化作用;此外,同其他化学组成一样,我们有理由相信黄土颗粒的粗细变化也是其Sr同位素比值变化的主要控制因素。为了考察黄土硅酸盐矿物中。⁸⁷Sr/⁸⁶Sr比值的受控因素,本研究在中国黄土高原由南到北选取蓝田(109.32°E,