Distribution of trace elements in the coastal sea sediments of Maslinica Bay, Croatia

Spatial distributions of trace elements in the coastal sea sediments and water of Maslinica Bay (Southern Adriatic), Croatia and possible changes in marine flora and foraminifera communities due to pollution were investigated. Macro, micro and trace elements’ distributions in five granulometric fractions were determined for each sediment sample. Bulk sediment samples were also subjected to leaching tests. Elemental concentrations in sediments, sediment extracts and seawater were measured by source excited energy dispersive X-ray fluorescence (EDXRF). Concentrations of the elements Cr, Cu, Zn, and Pb in bulk sediment samples taken in the Maslinica Bay were from 2.1 to over six times enriched when compared with the background level determined for coarse grained carbonate sediments. A low degree of trace elements leaching determined for bulk sediments pointed to strong bonding of trace elements to sediment mineral phases. The analyses of marine flora pointed to higher eutrophication, which disturbs the balance between communities and natural habitats.     

Water qualitiy and distribution of trace elements in the Doñana aquifer (SW Spain)

The variations of groundwater quality in the unconfined zone of the Almonte-Marismas aquifer, upon which Doñana National Park is located, are analysed. Most sampled points are multiple piezometers, allowing for the vertical distribution study of the hydrogeochemical characteristics in the aquifer. Temperature, pH, electrical conductivity, dissolved oxygen and redox potential were determined in the field. A large number of parameters, including major ions and a large amount of minor and trace elements, were analysed. In the southern zone, where aeolian sands crop out, water composition in the shallower part of the aquifer is of the sodium chloride type, with low pH (5.5–6) and mineralization (<200 μS/cm) values. As water circulates through the aquifer, bicarbonate and calcium concentrations increase slightly. In agricultural or urban zones, nitrates and sulphates present their highest contents in the upper part of the aquifer. In zones with low pH levels (around 6), concentration of many trace metals (Al, Co, Cr, Cu, Ni, Zn, etc.) also shows a distribution similar to that of sulphates and nitrates, which indicates its fertilizer-linked origin. In zones with neutral or alkaline pH, regardless of high nitrate content, concentration of the above mentioned metals is very low due to its immobilisation by surface adsorption processes. The distribution of Br contents also shows the effects of agricultural pollution.     

Late Cretaceous scleractinian corals from the rocky shore of Ivö Klack, southern Sweden, including some of the northernmost zooxanthellate corals

A relatively low diversity coral fauna comprising eight zooxanthellate, three azooxanthellate, and one unidentified species is described from a Late Cretaceous rocky shore at Ivö Klack, southern Sweden. All species, except the solitary azooxanthellate Paracyathus? sp., are represented by one or two specimens only, indicating low preservation potential similar to the aragonite-shelled gastropod fauna from the same locality. The fauna comprises one out of two northernmost zooxanthellate forms known and adds important environmental information to the fauna and depositional conditions of the rocky shore at Ivö Klack.     

Mid-Holocene stable isotope record of corals from the northern Red Sea

We present a study based on X-ray chronologies and the stable isotopic composition of fossil Porites spp. corals from the northern Gulf of Aqaba (Red Sea) covering the mid-Holocene period from 5750 to 4450 ¹⁴C years BP (before present). The stable oxygen and carbon isotopic compositions of five specimens reveal regular annual periodicities. Compared with modern Porites spp. from the same environment, the average seasonal δ ¹⁸O amplitude of the fossil corals is higher (by ca. 0.35–0.60‰), whereas annual growth rates are lower (by ca. 3.5 to 2 mm/year). This suggests stronger seasonality of sea surface temperatures and increased variability of the oxygen isotopic composition of the sea water due to changes in the precipitation and evaporation regime during the mid-Holocene. Most likely, summer monsoon rains reached the northern end of the Red Sea at that time. Average annual coral growth rates are diminished probably due to an increased input and resuspension of terrestrial debris to the shallow marine environment during more humid conditions. Our results corroborate published reports of paleodata and model simulations suggesting a northward migration of the African monsoon giving rise to increased seasonalities during the mid-Holocene over northeastern Africa and Arabia. Received: 4 January 1999 / Accepted: 13 September 1999     

云南华宁盘溪几种泥盆纪四射珊瑚

云南省华宁县盘溪地区的泥盆纪浅海相地层发育,珊瑚化石丰富,研究历史悠久,是中国南方重要的泥盆系剖面之一,它在国内外地层古生物学界久负盛名。1948年王鸿祯教授首次描述了盘溪等地泥盆纪的四射珊瑚19属36种(包括变种、未定种等),其中有19新种,自下而上建立了G、C、K、E、T、P、D等7个珊瑚层(horizon),奠定了滇东泥盆纪生物地层研究的基础,该文至今仍一直被国内外地层古生物学界同行所引用和参考。文中描述了盘溪泥盆纪四射珊瑚13属13种(包括未定种和近似种)及其上覆下石炭统的四射珊瑚1属2种。文章还着重讨论了泥盆系的南盘江组、一打得组和在结组的地质时代以及泥盆—石炭系界线等地层问题。     

NS935钻孔沉积物不活泼微量元素记录与陆源输入变化探讨

探讨了NS93－5钻孔沉积物的部分高场强元素和大离子亲石元素的含量变化，结果表明，Ti、Rb、Ga、Y、Zr、Nb、Cs、Hf、Ta、Th和稀土元素（REE）相互间含量变化具有很好的相关关系，反映这些元素均基本来自碎屑组分。经Ti和Sc标准化后这些元素含量的变化，以及Zr/Y等特征元素比值和Ge异常指数Ce/Ce、Eu异常指数Eu/Eu的变化，均反映出碎屑输入的通量或者组成的变化，例如火山灰的富集。其中一些变化与气候变化有关，可能反映周边陆壳的风化强度的波动。NS93－5钻孔沉积物的不活泼元素记录，可提供反映输入陆壳物源区的环境演变证据。     

Patterns of Pacific decadal variability recorded by Indian Ocean corals

We investigate Pacific Decadal Oscillation (PDO) signals recorded by two bimonthly resolved coral δ¹⁸O series from La Réunion and Ifaty (West Madagascar), Indian Ocean from 1882 to 1993. To isolate the main PDO frequencies, we apply a band pass filter to the time series passing only periodicities from 16 to 28 years. We investigate the covariance patterns of the coral time series with sea surface temperature (SST) and sea level pressure (SLP) of the Indian and Pacific Oceans. In addition, the empirical orthogonal functions of the filtered SST and SLP fields (single and coupled) are related to the filtered coral times series. The covariance maps show the typical PDO pattern for SST and SLP, confirming the coupling between the Indian and Pacific Oceans. Both corals show the strongest signal in boreal summer. The La Réunion (Ifaty) coral better records SST (SLP) than SLP (SST) pattern variability. We suggest that the filtered La Réunion coral δ¹⁸O represents δ¹⁸O of seawater that varies with the South Equatorial Current, which, in turn, is linked with the SST PDO. The filtered Ifaty coral δ¹⁸O represents SST and is remotely linked with the SLP PDO variability. A combined coral record of the Ifaty and La Réunion boreal summer δ¹⁸O series explains about 64% of the variance of the coupled SST/SLP PDO time series. AGU OS06 special issue “Ocean’s role in climate change—a paleo perspective”.     

Chemical and mineralogical composition of fluvial sediments (Bistrita River,Romania): Geogenic vs. anthropogenic input into rivers on its way through mining areas

The upper reaches of the Bistrita drainage system were selected as a natural test site to determine the geogenic and anthropogenic input into fluvio-lacustrine systems in humid mid-latitude morphoclimatic zones. The reason for this selection lies in the complex geology and its metallogenic evolution leading to a great variety of Fe, Mn, U, and polymetallic sulfides ore deposits. It sparked an intense mining activity during the past centuries with a strong impact on the drainage system similar to many mineralized sites in the world which are still under exploitation. Sediment samples from Bistrita River were analyzed by means of X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), near-infrared (NIR) and micro-Raman spectroscopy (μ-Raman).Our results revealed that the chemical and mineralogical built-up of the stream sediments is mainly geogenic, with most of the trace elements accumulated in the river sediments derived from the source rocks exposed in catchment area of the River Bistrita. A strong input by man has been detected in the drainage system near abandoned mining sites. The trace elements are mainly accommodated in the structure of detrital minerals representative of the clastic aureole around the source rocks, and to a lesser extent adsorbed onto the surface of clay minerals. The REE incorporated into muscovite furnish evidence of having derived from the source rocks, prevalently mica schists exposed by supergene processes in the provenance area and rule out a neoformation of clay minerals on transport and deposition.     

Determination of element/Ca ratios in foraminifera and corals using cold- and hot-plasma techniques in inductively coupled plasma sector field mass spectrometry

We have developed a rapid and precise procedure for measuring multiple elements in foraminifera and corals by inductively coupled plasma sector field mass spectrometry (ICP-SF-MS) with both cold- [800 W radio frequency (RF) power] and hot- (1200 W RF power) plasma techniques. Our quality control program includes careful subsampling protocols, contamination-free workbench spaces, and refined plastic-ware cleaning process. Element/Ca ratios are calculated directly from ion beam intensities of ²⁴Mg, ²⁷Al, ⁴³Ca, ⁵⁵Mn, ⁵⁷Fe, ⁸⁶Sr, and ¹³⁸Ba, using a standard bracketing method. A routine measurement time is 3–5 min per dissolved sample. The matrix effects of nitric acid, and Ca and Sr levels, are carefully quantified and overcome. There is no significant difference between data determined by cold- and hot-plasma methods, but the techniques have different advantages. The cold-plasma technique offers a more stable plasma condition and better reproducibility for ppm-level elements. Long-term 2-sigma relative standard deviations (2-RSD) for repeat measurements of an in-house coral standard are 0.32% for Mg/Ca and 0.43% for Sr/Ca by cold-plasma ICP-SF-MS, and 0.69% for Mg/Ca and 0.51% for Sr/Ca by hot-plasma ICP-SF-MS. The higher sensitivity and enhanced measurement precision of the hot-plasma procedure yields 2-RSD precision for μmol/mol trace elements of 0.60% (Mg/Ca), 9.9% (Al/Ca), 0.68% (Mn/Ca), 2.7% (Fe/Ca), 0.50% (Sr/Ca), and 0.84% (Ba/Ca) for an in-house foraminiferal standard. Our refined ICP-SF-MS technique, which has the advantages of small sample size (2–4 μg carbonate consumed) and fast sample throughput (5–8 samples/hour), should open the way to the production of high precision and high resolution geochemical records for natural carbonate materials.     

高压密闭消解-电感耦合等离子体质谱法测定和田玉中15种稀土元素

和田玉的稀土元素丰富,准确测定稀土元素含量对于揭示和田玉成矿物质来源、成矿流体的性质和矿床成因具有重要的意义。本文通过比较硝酸-氢氟酸、四硼酸锂-偏硼酸锂碱熔两种前处理方法,确定了使用硝酸-氢氟酸溶样,再采用电感耦合等离子体质谱法（ICP-MS）测定和田玉中钇镧铈镨钕钐铕钆铽镝钬铒铥镱镥15种稀土元素的含量。为降低基体效应,以¹⁰³Rh和⁴⁹In作内标补偿基体效应和校正灵敏度漂移,样品检出限为0.0008~0.0091μg/L,回收率为101.0%~120.0%,精密度（RSD）为0.55%~1.83%（n=11）。本方法的用酸量少,空白值低,应用于不同地区和田玉的分析,其稀土元素的配分模式特征为右倾型轻稀土富集,初步探讨的稀土元素丰度特征可为研究主产区宝玉石的矿床成因提供依据。     

Trace element partitioning in the Morasko meteorite from Poznan, Poland

The nickel–iron meteorite of Morasko shows isolated inclusions of troilite in the bulk mass of a Fe,Ni-alloy. During a segregation of the FeS phase chalcophile trace elements were collected from the melt. The solidification of the Fe,Ni-phase occurred probably later, incorporating thereby mainly siderophile trace elements. To prove this general assumption selected trace elements were determined and reveal in the two phases of the present meteorite a characteristic distribution pattern. The meteorite of Morasko is in close conformity to the iron meteorite group IAB with rounded dark FeS inclusions.     

Geochemical characterization of the mining district of Linares (Jaen,Spain) by means of XRF and ICP-AES

Linares (Jaen, Spain) has been subjected to an intense mining and metallurgic activity during 2500 years. Basically, lead and silver have been extracted from galena; as well as copper and zinc. Different studies have been conducted to evaluate trace element concentrations to obtain relationships with anthropogenic and geologic factors. The analytical results of these studies have been obtained with ICP-AES. This analytical technique is relatively expensive and inaccessible in zones with scarce economic means. In this study, XRF analyses have been conducted and the obtained results are presented, as well as a comparison with the previously obtained ICP results. In both cases, a cluster analysis has been made to try to identify the same relations in the target area. 5 groups have been identified, mainly related with lithology. Only 10 of the 122 grid squares (each one of 1 km²) are classified in different groups if the cluster analysis is conducted with XRF results or ICP results. ICP classifies better where these grid squares are located, mostly, in contact zones of different lithologies.     

Major and trace element geochemistry in upper Ganga river in the Himalayas, India

Chemical weathering and resulting water compositions in the upper Ganga river in the Himalayas were studied. For the first time, temporal and spatial sampling for a 1 year period (monthly intervals) was carried out and analyzed for dissolved major elements, trace elements, Rare Earth Elements (REE), and strontium isotopic compositions. Amounts of physical and chemical loads show large seasonal variations and the overall physical load dominates over chemical load by a factor of more than three. The dominant physical weathering is also reflected in high quartz and illite/mica contents in suspended sediments. Large seasonal variations also occur in major elemental concentrations. The water type is categorized as HCO₃^––SO₄^2––Ca²⁺ dominant, which constitute >60% of the total water composition. On an average, only about 5–12% of HCO₃^– is derived from silicate lithology, indicating the predominance of carbonate lithology in water chemistry in the head waters of the Ganga river. More than 80% Na⁺ and K⁺ are derived from silicate lithology. The silicate lithology is responsible for the release of low Sr with extremely radiogenic Sr (⁸⁷Sr/⁸⁶ Sr>0.75) in Bhagirathi at Devprayag. However, there is evidence for other end-member lithologies for Sr other than carbonate and silicate lithology. Trace elements concentrations do not indicate any pollution, although presence of arsenic could be a cause for concern. High uranium mobilization from silicate rocks is also observed. The REE is much less compared to other major world rivers such as the Amazon, perhaps because in the present study, only samples filtered through <0.2 m were analysed. Negative Eu anomalies in suspended sediments is due to the excess carbonate rock weathering in the source area.     

Removal of trace elements from landfill leachate by calcite precipitation

Spontaneous precipitation of secondary calcite (CaCO₃) has been observed in 25 samples of landfill leachate-polluted stream waters. During the 6-month precipitation experiment, the formation of calcite acts as a principal trace-element scavenging process. The concentrations of Fe, Sr, Ba and Mn and other trace elements in solution significantly decreased as calcite formed during the experiments. The PHREEQC-2 geochemical code indicated high supersaturation of the initial leachate-polluted waters with respect to calcite. The chemical/mineralogical study (SEM/EDS, XRD, ICP MS) revealed that this newly formed calcite contains considerable amounts of metals and metalloids removed from solution. Such a geochemical process can be considered to be important for spontaneous decontamination in landfill-affected environments (stream sediments, soils) or landfill technical facilities (settling basins). This removal takes place especially during dry periods with low rain precipitation, when the landfill waters exhibit both higher alkalinity and higher trace element concentrations.     

Study of the distribution of Trace elements in soils in and around Mysore city,Karnataka

Soil samples collected from various places in and around Mysore were analyzed for the total trace elements such as Fe, Mn, Cu, Zn, Pb, and Cd. The results of the analysis indicate that the concentration of lead and cadmium in soils is below 2.5 g ml^–1 and 0.2 g ml^–1, respectively, which are the minimum detection levels, whereas the concentration of iron, manganese, copper, and zinc in most of the samples is within the global average ranges of 3%, 500–1000 g g^–1, 15–40 g g^–1, and 50–100 g g^–1, respectively. The investigated area has the presence of gneisses and schists, in which partly there are igneous intrusions and pegmatitic intrusions. There are amphibolite enclaves in gneisses that account for the higher concentration of trace elements. The lower concentration may be attributed to the presence of silicic type of rock.     

Mobilization and redistribution of major and trace elements in two weathering profiles developed on serpentinites in the Lomié ultramafic complex, South-East Cameroon

The behaviour of major and trace elements have been studied along two serpentinite weathering profiles located in the Kongo-Nkamouna and Mang North sites of the Lomié ultramafic complex.The serpentinites are characterized by high SiO₂ and MgO contents, very low trace, rare earth and platinum-group element contents. Lanthanide and PGE contents are higher in the Nkamouna sample than in Mang North. Normalized REE patterns according to the CI chondrites reveal that: (i) all REE are below chondrites abundances in the Mang North sample; (ii) the (La/Yb)_N ratio value is higher in the Nkamouna sample (23.72) than in the Mang one (1.78), this confirms the slightly more weathered nature of the Nkamouna sample. Normalized PGE patterns according to the same CI chondrites reveal a negative Pt anomaly in the Mang sample. The Nkamouna sample is characterized by a flat normalized PGE pattern.All element contents increase highly from the parent rock to the coarse saprolite.In the weathering profiles, Fe₂O₃ contents decrease from the bottom to the top contrarily to Al₂O₃, SiO₂ and TiO₂. The contents of alkali and alkaline oxides are under detection limit.Concerning trace elements, Cr, Ni, Co, Cu, Zn and Sc decrease considerably from the bottom to the top while Zr, Th, U, Be, Sb, Sn, W, Ta, Sr, Rb, Hf, Y, Li, Ga, Nb and Pb increase towards the clayey surface soil. Chromium, Ni and Co contents are high in the weathered materials in particular in the saprolite zone and in the nodules.REE contents are high in the weathered materials, particularly in Nkamouna. Their concentrations decrease along both profiles. Light REE are more abundant than heavy REE. Normalized REE patterns according to the parent rock reveal positive Ce anomalies in all the weathered materials and negative Eu anomalies only at the bottom of the coarse saprolite (Nkamouna site). Positive Ce anomalies are higher in the nodular horizon of both profiles. An additional calculation method of lanthanide anomalies, using NASC data, confirms positive Ce anomalies ([Ce/Ce^*]_NASC = 1.15 to 60.68) in several weathered materials except in nodules ([Ce/Ce^*]_NASC = 0.76) of the upper nodular horizon (Nkamouna profile). The (La/Yb)_N ratios values are lower in the Nkamouna profile than in Mang site.PGE are more abundant in the weathered materials than in the parent rock. The highest contents are obtained in the coarse saprolite and in the nodules. The elements with high contents along both profiles are Pt (63–70 ppb), Ru (49–52 ppb) and Ir (41 ppb). Normalized PGE patterns show positive Pt anomalies and negative Ru anomalies.The mass balance evaluation, using thorium as immobile element, reveals that:

– major elements have been depleted along the weathering profile, except for Fe, Mn and Ti that have been enriched even only in the coarse saprolite;

– all the trace elements have been depleted along both profiles, except for Cr, Co, Zn, Sc, Cu, Ba, Y, Ga, U and Nb that have been enriched in the coarse saprolite;

– rare earth elements have been abundantly accumulated in the coarse saprolite, before their depletion towards the top of the profiles;

– platinum-group elements have been abundantly accumulated in the coarse saprolite but have been depleted towards the clayey surface soil.

Moreover, from a pedogenetical point of view, this study shows that the weathering profiles are autochtonous, except in the upper part of the soils where some allochtonous materials are revealed by the presence of zircon grains.     

柿竹园和香炉山W多金属矿床中硫化物微量元素特征:来自原位LA-ICP-MS分析

华南包括两个世界级的W矿带,分别是南岭和江南造山带W成矿带。柿竹园W多金属矿床位于南岭地区,香炉山W矿床位于江南造山带东北部。两个矽卡岩W矿床都发育硫化物成矿阶段。但硫化物和成矿元素组成存在显著的差异。前者由含Pb、Zn、Ag硫化物和黝铜矿、银黝铜矿、含Ag斜方辉铅铋矿和铁硫锡铜矿硫盐组成;后者主要为磁黄铁矿。柿竹园远接触带Pb-Zn-Ag矿脉中硫化物(闪锌矿、黄铜矿、方铅矿和磁黄铁矿)较富集B、Mn、Cr、Sb、Sn和Hg,香炉山似层状矽卡岩和硫化物-白钨矿矿体中硫化物(磁黄铁矿、黄铜矿和闪锌矿)较富集W、Se和Bi。两个矿床中黄铜矿、闪锌矿和方铅矿较富集Ag,黄铜矿、闪锌矿富集In和Sn,闪锌矿还富集Cd。两个矿床中的硫化物微量元素分析表明与矽卡岩W矿成矿相关的硫化物可载有多种微量元素。这些元素参与到硫化物中程度由多种因素控制。具体如下,硫化物中B含量高低与成矿相关岩体中B含量相关;在相对高温和还原条件下,硫化物中W含量较高;闪锌矿中Mn和Cd与Zn发生取代作用; Cr可以一定程度进入到硫化物中,并受成矿流体中Cr含量影响; Se与S发生了一定程度的取代进入硫化物,并受流体中它的含量控制; Bi在闪锌矿与黄铜矿易形成固溶体;硫化物中Sb含量受初始流体中它的含量影响,方铅矿中易包裹一定的辉锑矿(Sb_2S_3)或含Sb的硫盐矿物; Ag是否形成独立的矿物相和进入哪些硫化物中,取决于流体中Ag的初始含量和硫化物的沉淀次序;硫化物中Hg的含量受温度影响。     

Determination of elemental affinities by density fractionation of bulk coal samples from the Chongqing coal district, Southwestern China

The occurrence and distribution of major and trace elements have been investigated in two coal-bearing units in the Chonqing mining district (South China): the Late Permian and Late Triassic coals.The Late Permian coals have higher S contents than the Late Triassic coals due to the fixation of pyrite in marine-influenced coal-forming environments. The occurrence of pyrite accounts for the association of a large number of elements (Fe, S, As, Cd, Co, Cu, Mn, Mo, Ni, Pb, Sb, Se, and Zn) with sulphides, as deduced from the analysis of the density fractions. The marine influence is probably also responsible for the organic association of B. The REEs, Zr, Nb, and Hf, are enriched by a factor of 2–3 with respect to the highest levels fixed for the usual worldwide concentration ranges in coal for these elements. The content of these elements in the Late Permian coal is higher by a factor of 5–10 with respect to the Late Triassic coal. Furthermore, other elements, such as Cu, P, Th, U, V, and Y, are relatively enriched with respect to the common range values, with maximum values higher than the usual range or close to the maximum levels in coal. The content of these elements in the Late Permian coal is higher than the Late Triassic coal. These geochemical enrichments are the consequence of the occurrence, in relatively high levels, of phosphate minerals, such as apatite, xenotime, and monazite, as deduced from the study of the density fractions obtained from the bulk coal.The Late Triassic coal has a low sulphur content with a major organic affinity. The trace element contents are low when compared with worldwide ranges for coal. In this coal, the trace element distribution is governed by clay minerals, carbonate minerals, and to a lesser extent, by organic matter and sulphide minerals.Major differences found between late Permian and Triassic coals are probably related to the source rocks, given that the main source rock of the late Permian epicontinental marine basin is the Emeishan basalt formation, characterised by a high phosphate content.     

橄榄石微量元素原位分析的现状及其应用

随着高精度EMPA和LA-ICP-MS分析技术的发展和矿物微量元素测试精度的提高,利用橄榄石中的微量元素示踪地幔部分熔融、地幔交代作用、岩浆早期结晶过程等地质问题成为近年来一个新兴的研究方向。一系列开拓性的研究发现也被陆续的发表,主要涉及橄榄石中Ni、Co、Al、Cr、Zn、Ti、Li、V、Sc、Mn、Ca和P等元素的示踪使用。一些卓有成效的示踪方法为:Ca、Al、Ti、Ni及Mn能够很好的用于区分橄榄石捕掳晶和斑晶;橄榄石-尖晶石地幔演化趋势线(OSMA:olivine-spinel mantle array)图解可以用于表征岩浆源区的亏损程度;玄武岩中橄榄石斑晶的Li同位素及Li含量可以很有效地指示岩浆源区是否存在地壳物质再循环及地幔交代作用;橄榄石斑晶中Ni、Ca、Mn、Cr和Al协变关系图解可以识别岩浆的辉石岩源区;利用橄榄石捕掳晶中Zr和Sc的含量差异特征可将橄榄岩中三种最主要的类型(尖晶石橄榄岩、石榴石橄榄岩以及尖晶石-石榴石橄榄岩)区分开来;一些元素的比值或组合(例如Ni/Co、Fe/Mn、V/Sc、Zr和Sc、Ca和Ti)可以指示源区交代作用、岩浆作用过程及氧化状态;基于橄榄石中Al、Cr及Ca的地质温度计可以为推算地幔热状态提供新方法;基于橄榄石分离结晶Fo-NiO演化线的原始岩浆计算模型可以较好的推算原始岩浆成分;利用橄榄石的环带及微量元素的扩散机制可以判别更多岩石成因信息,如识别交代介质、熔体类型以及地质构造背景等。基于上述最新研究的相关资料和已有成果,本文对橄榄石微量元素的地球化学示踪方法做系统性的归纳整理,并对橄榄石微量元素赋存状况、橄榄石微量元素测试方法、橄榄石微量元素的使用条件及需注意的问题等进行讨论,为读者在做相关研究时提供参考。     

松潘-甘孜地块三叠系砂岩的地球化学特征及其意义

松潘-甘孜地块位居中国西南部,北邻华北地块,西与青藏高原毗邻,东南缘与扬子地块相连.该区出露的巨厚层砂岩SiO2含量变化范围大为48.64%～71.77%,稳定元素（Al2O3,Fe2O3,MnO）与不稳定元素（MgO,K2O,Na2O）基本持平,CIW值较低;La/Co值集中于3.0～4.5,Th/Co集中于1.0～1.5,La/Th值集中于2.7～3.1,Th/U值均大于4.0,轻稀土元素含量大于重稀土元素含量,具Eu负异常,稀土元素分布形态与上地壳一致;锆石的U-Pb年龄集中分布于1500～1900Ma、700～900Ma、200～400Ma,与扬子地块、南秦岭的岩浆活动相一致.分析表明松潘-甘孜地块具有稳定的物源区,主要以扬子地块为主;其碎屑母岩应主要源自上地壳,以长英质成分为主.松潘-甘孜地块在三叠纪时期处于大陆岛弧环境,周边地区基本处于稳定状态,没有大规模构造运动和岩浆活动,扬子地块向华北地块的俯冲明显减弱或可能已经停止,秦岭造山运动基本已经完成.