共查询到20条相似文献，搜索用时 31 毫秒
1.
F.J. Flanagan 《Geochimica et cosmochimica acta》1974,38(12):1731-1744
A revised list of reference samples of interest to geoscientists has been extended to include samples for the agronomist, the archaeologist and the environmentalist. In addition to the source from which standard samples may be obtained, references or pertinent notes for some samples are included.The number of rock reference samples is now almost adequate, and the variety of ore samples will soon be sufficient. There are very few samples for microprobe work. Oil shales will become more important because of the outlook for world petroleum resources. The dryland equivalent of a submarine basalt might be useful in studies of sea-floor spreading and of the geochemistry of basalts.The Na- and K-feldspars of BCS (British Chemical Standards—Bureau of Analysed Samples), NBS (National Bureau of Standards), and ANRT (Association Kationale de la Recherche Technique) could serve as trace-element standards if such data were available. Similarly, the present NBS flint and plastic clays, as well as their predecessors, might be useful for archaeological pottery studies. The International Decade for Ocean Exploration may stimulate the preparation of ocean-water standards for trace elements or pollutants and a standard for manganese nodules. 相似文献
2.
L.J. SCHWARZ A.F. DORRZAPF Jr. W.B. CRANDELL F.J. FLANAGAN 《Geostandards and Geoanalytical Research》1986,10(1):99-107
Some trace-element contents of U.S. Geological Survey (USGS) samples, biotite Btt-1 and hornblende Hbl-1, were determined by both computerized semi-quantitative spectrographic analysis and instrumental neutron activation analysis. An equal number of portions of the Centre de Recherches Pétrographiques et Géochimiques (CRPG) samples, biotite Mica-Fe and phlogopite Mica-Mg, were randomized with portions of the USGS samples and analyzed simultaneously to allow direct comparisons of trace elements in the biotites. Mica-Fe has concentrations of Cs, Hf, Ta and Zn that are greater by factors of 3 or more than those in Btt- 1. Although the Co contents of the two biotites are nearly equal, the amounts of Cr, Sc, La and the rare earth elements are significantly greater in Btt-1. Mica-Mg contains larger amounts of Cs and Rb than does Hbl-1, whereas the Cr content of Hbl-1 is 15 times that of Mica-Mg. Btt-1 and Hbl-1 may be useful as comparison samples for the analysis of biotites and hornblendes after other data are available. 相似文献
3.
Doklady Earth Sciences - The results of studies of the trace-element contents in olivine and plagioclase of chondrules from equilibrated ordinary chondrite Orlovka (H5) are reported. Olivine is... 相似文献
4.
Mineralogy of soils from two continental-scale transects across the United States and Canada and its relation to soil geochemistry and climate 总被引：4，自引：4，他引：0
Quantitative mineralogy correlates with major-, minor- and trace-element chemistry for 387 samples of A-horizon and deeper soils collected from east–west and north–south transects across the USA and Canada, where the deeper soils were collected beneath the A-horizon samples. Concentrations of the major elements correlate with specific mineral phases. Minor- and trace-element concentrations correlate with the same phases as the major elements with which they share similar geochemical behavior. Concentrations of quartz and feldspar correlate with precipitation trends east of the Rocky Mountains, and are independent of the underlying rock type and age, indicating that the weathering of soils in this region may have reached a steady-state mineralogy. Other trends in mineralogy relate to physiographic province. The combination of quantitative mineralogy and chemical analysis yields a much richer portrait of soils than can be gained from chemistry alone, because the origins of chemical trends and the chemical availability of specific elements are related to mineralogy. 相似文献
5.
N. Özlü 《Mineralium Deposita》1983,18(3):469-476
This work deals with a concise but comprehensive study of trace-element distribution in the bauxite deposits of Mediterranean belt. Although the alloctonous and mainly detritic characters of several “karst bauxite” deposits are well established, their parent rock has remained largely enigmatic. Evidence is available that some chemical elements, notably Zr, Cr and Ga are largely immobile during the weathering and diagenesis and study of such trace-elements in “karst bauxites” permits to make an approach to the lithological nature of their parent rocks. It is shown, by reference to analyses of bauxites from Mediterranean areas, that all the deposits studied are aligned from a Cr rich pole related to ultramafics to another pole rich in Ga and Zr contents and in genetical relation with acidic parent rocks. The results obtained by this way have been controlled by application of “trace-element accumulation coefficient” which permits to distinguish four principal zones of bauxite derived from the parent rock of different lithological characters (Fig. 3). 相似文献
6.
Method peculiarities of multielemental analysis of rocks with inductively-coupled plasma mass spectrometry 总被引：1，自引：0，他引：1
Ya. V. Bychkova M. Yu. Sinitsyn D. B. Petrenko I. Yu. Nikolaeva I. A. Bugaev A. Yu. Bychkov 《Moscow University Geology Bulletin》2017,72(1):56-62
Decomposition of samples with a poorly soluble complex matrix for the analysis of the trace-element composition with high-resolution inductively-coupled plasma mass spectrometry was designed and tested. Analytical and method problems of the selection and preparation of samples are described and their solutions are proposed. The correctness of sample preparation was verified using analysis of standard rock samples. 相似文献
7.
The uranium contents of thirteen rock reference samples from the Centre de Recherches Pétrographiques et Géochimiques, Nancy, France, were determined by delayed-neutron activation analysis. Four others from the same laboratory were found to have uranium concentrations below our limit of detection. Meaningful comparison of our data with other workers is presently not possible (i) because of the paucity of uranium data and (ii) because of the disparity of uranium data on the samples for which uranium data exist. 相似文献
8.
NICOLAS J. RAWLENCE DAVID J. LOWE JAMIE R. WOOD JENNIFER M. YOUNG G. JOCK CHURCHMAN YU‐TUAN HUANG ALAN COOPER 《第四纪科学杂志》2014,29(7):610-626
Palaeoenvironmental DNA (PalEnDNA) is defined as ancient DNA (aDNA) originating from disseminated genetic material within palaeoenvironmental samples. Sources of PalEnDNA include marine and lake sediments, peat, loess, till, ice, permafrost, palaeosols, coprolites, preserved gut contents, dental calculus, tephras, and soils as well as deposits in caves/rockshelters and at archaeological sites. PalEnDNA analysis provides a relatively new tool for Quaternary and archaeological sciences and its applications have included palaeoenvironmental and palaeodietary reconstructions, testing hypotheses regarding megafaunal extinctions, human–environment interactions, taxonomic studies, and studies of DNA damage. Because PalEnDNA samples comprise markedly different materials, and represent wide‐ranging depositional and taphonomic contexts, various issues must be addressed to achieve robust, reproducible findings. Such issues include climatic and temporal limitations, the biological origin and state (free versus bound) of PalEnDNA, stratigraphic reliability, sterile sampling, ability to distinguish modern from aDNA signals, DNA damage and PCR amplification, DNA extraction methods, and taxonomic resolution. In this review, we provide a non‐specialist introduction to the use of PalEnDNA for Quaternary and archaeological researchers, assess attributes and limitations of this palaeoenvironmental tool, and discuss future prospects of using PalEnDNA to reconstruct past environments. 相似文献
9.
The combined use of both (1) low-flow purging and sampling and (2) trace-metal clean techniques provides more representative
measurements of trace-element concentrations in groundwater than results derived with standard techniques. The use of low-flow
purging and sampling provides relatively undisturbed groundwater samples that are more representative of in situ conditions,
and the use of trace-element clean techniques limits the inadvertent introduction of contaminants during sampling, storage,
and analysis. When these techniques are applied, resultant trace-element concentrations are likely to be markedly lower than
results based on standard sampling techniques. In a comparison of data derived from contaminated and control groundwater wells
at a site in California, USA, trace-element concentrations from this study were 2–1000 times lower than those determined by
the conventional techniques used in sampling of the same wells prior to (5 months) and subsequent to (1 month) the collections
for this study. Specifically, the cadmium and chromium concentrations derived using standard sampling techniques exceed the
California Maximum Contaminant Levels (MCL), whereas in this investigation concentrations of both of those elements are substantially
below their MCLs. Consequently, the combined use of low-flow and trace-metal clean techniques may preclude erroneous reports
of trace-element contamination in groundwater.
Received: October 1997 Revised: May 1998 Accepted: December 1998 相似文献
10.
Evidence for distinct stages of magma history recorded by the compositions of accessory apatite and zircon 总被引：1，自引：0，他引：1
A. J. Miles C. M. Graham C. J. Hawkesworth M. R. Gillespie R. W. Hinton 《Contributions to Mineralogy and Petrology》2013,166(1):1-19
Accessory minerals contain a robust and accessible record of magma evolution. However, they may reflect relatively late-stage conditions in the history of the host magmas. In the normally zoned Criffell granitic pluton (Scotland), whole-rock (WR) compositions reflect open system assimilation and fractional crystallisation at depths of >11 km, whereas amphibole barometry and the absence of inherited zircon suggest that the observed mineral assemblages crystallised following emplacement of magmas with little or no crystal cargo at depths of 4–6 km. The crystallisation history is documented by large trace-element variations amongst apatite crystals from within individual samples: decreasing LREE and Th concentrations in apatite crystals from metaluminous samples reflect broadly synchronous crystallisation of allanite, whereas lower LREE and Th, and more negative Nd anomalies in apatites from peraluminous samples reflect the effects of monazite crystallisation. WR evolution is likely to have occurred within a deep crustal hot zone where H2O-rich (~6 wt%), low-viscosity magmas segregated and ascended adiabatically in a super-liquidus state, leading to resorption of most entrained crystals. Stalling, emplacement and crystallisation resulted from intersection with the H2O-saturated liquidus at ~4 km. H2O contents are as important as temperature in the development of super-liquidus magmas during ascent, blurring distinctions between apparently ‘hot’ and ‘cold’ granites. The trace-element contents of most accessory minerals are controlled by competitive crystallisation of other accessory minerals in small melt batches, consistent with the incremental assembly of large granitic plutons. 相似文献
11.
14C加速器质谱(14C-AMS)测年技术具有测量精度高、速度快以及样品需求量少的特点,为考古年代学研究提供了一种新的途径.通过对中国考古学中的一些断代难题,例如夏商周断代工程、城头山遗址的环境考古、江西瑞昌铜岭冶铜遗址的14C-AMS测年分析,以及周原黄土地层学与年代学相结合的研究,总结了14C-AMS测年技术在提供可靠的年代、解决考古年代学中微量样品的测年难题方面,具有不可替代的优势.指出考古学的研究既要与地层学相结合,更重要的是与现代高灵敏度的测年技术相结合,并认为14C-AMS测年将成为未来中国考古年代学研究的一个重要方向. 相似文献
12.
Two discriminant function models are constructed in order to distinguish major- and trace-element geochemical patterns characteristic for radiolarian cherts from the Zagorje–Mid-Transdanubian Zone ophiolite mélange of NW Croatia. The models are subsequently used to assign new samples from the adjacent magmatic–sedimentary complex extending from the Central Dinaridic Ophiolite Belt in NW Bosnia and thereby to test their applicability in similar cases when clear field relations are absent. In both models the first discriminant function explains the most part of the system variability. However, between the two, the trace-element model proves itself as a more helpful predictive tool presenting a straightforward example of correct classification of samples into three pre-defined groups (Triassic-basin, Triassic-slope and Jurassic radiolarian cherts). This result is extended further, with allocation of all samples from the test region into a single group (Jurassic) according to their trace-element geochemistry. 相似文献
13.
The four most abundant minerals generally found in Euramerican bituminous coals are quartz, kaolinite, illite and pyrite. These four minerals were isolated by density separation and handpicking from bituminous coal samples collected in the Ruhr Basin, Germany and the Appalachian basin, U.S.A. Trace-element concentrations of relatively pure ( 99+%) separates of major minerals from these coals were determined directly by using instrumental neutron activation analysis (INAA). As expected, quartz contributes little to the trace-element mass balance. Illite generally has higher trace-element concentrations than kaolinite, but, for the concentrates analyzed in this study, Hf, Ta, W, Th and U are in lower concentrations in illite than in kaolinite. Pyrite has higher concentrations of chalcophile elements (e.g., As and Se) and is considerably lower in lithophile elements as compared to kaolinite and illite. Our study provides a direct and sensitive method of determining trace-element relationships with minerals in coal.Mass-balance calculations suggest that the trace-element content of coal can be explained mainly by three major minerals: pyrite, kaolinite and illite. This conclusion indicates that the size and textural relationships of these major coal minerals may be a more important consideration as to whether coal cleaning can effectively remove the most environmentally sensitive trace elements in coal than what trace minerals are present. 相似文献
14.
Powdered rock samples from strata of the Witwatersrand System's sedimentary succession have been analyzed by x-ray fluorescence and optical spectroscopy techniques for nineteen elements. Using discriminant analysis it is possible to identify strata based on their trace-element compositions. 相似文献
15.
平顶山矿区煤矸石特征及综合利用途径 总被引：5，自引：0，他引：5
在查明平顶山矿区煤矸石占地面积、矸石积存量及年排矸量的基础上，作者系统地采集了全矿区井上和井下煤矸石样品，进行了化学分析、工业分析、光谱分析、Ｘ射线衍射、岩矿鉴定和扫描电镜测定。查明了本矿区煤矸石的成分、矿物及微量元素特征。并指出了各类矸石可资进行综合利用的途径。 相似文献
16.
《Russian Geology and Geophysics》2015,56(6):874-884
We present results of geochemical and Sm-Nd isotope studies of high-grade metaterrigenous rocks of the Kitoi and northwestern Irkut terranes of the Sharyzhalgai uplift on the Siberian Platform in comparison with paragneisses of the southeastern Irkut terrane. The metasedimentary rocks of the first region are high-alumina garnet-sillimanite-cordierite-bearing paragneisses; their protoliths were mostly mudstones and pelitic mudstones by major-element composition. The low-alumina biotite gneisses of the Kitoi terrane formed, most likely, from magmatic protoliths similar in petrochemical features to intraplate volcanics. The major factor controlling the composition of the studied high-alumina paragneisses is precipitation of most of incompatible trace elements in the clay fraction of sediments, as evidenced from the positive correlation between trace-element and Al2O3 contents. The Cr and Ni contents, showing a positive correlation with MgO and no correlation with Al2O3, are an indicator of the contribution of the mafic-source material to the formation of high-alumina rocks. The contribution of a mafic source-derived material to the formation of terrigenous rocks increases in passing from Kitoi to northwestern Irkut terrane. The high-alumina and garnet-biotite paragneisses of the southeastern Irkut terrane are similar in trace-element patterns to the analogous rocks of the Kitoi terrane and northwestern part of the Irkut terrane but show higher Th contents and a distinct negative Eu anomaly related to the change in the composition of the felsic source. The participation of felsic potassic igneous rocks in the formation of the southeastern terrigenous sediments is consistent with their deposition after the Neoarchean collision processes (metamorphism and granite magmatism), whereas sedimentation in the Kitoi and northwestern Irkut terranes preceded them. The Sm-Nd isotope characteristics indicate that the latter sediments formed mostly as a result of the erosion of the Paleo-Mesoarchean crust, whereas the metasediments of the southeastern Irkut terrane formed with the participation of Paleoproterozoic juvenile rocks. Thus, the variations in the trace-element and isotope compositions of the high-grade metamorphosed terrigenous rocks reflect recycling and growth of the continental crust of the Sharyzhalgai uplift during the Neoarchean-Pa- leoproterozoic transition. 相似文献
17.
《Comptes Rendus Geoscience》2018,350(6):319-330
Morocco hosts numerous archaeological sites, some of which are part of the UNESCO world heritage. Many of these sites, especially funerary mounds also called tumuli, or rock engravings and ceramics, are located in remote areas with limited access, particularly in the Saharan Morocco desert. We developed a remote sensing and GIS model to identify areas with high potential for hosting archaeological sites in the Awserd region of southern Morocco. A field campaign in a “reference site” zone of 21 km2 has revealed 233 archaeological sites. Here we use satellite images and Digital Elevation Models to examine with various techniques (spatial analysis, statistical techniques, and fuzzy logic functions) the relations between the distribution of the archaeological sites and geo-environmental variables such as ground geology, topographic elevation and slope, orientation (aspect), and distance to water sources. We derive empirical relations that reveal that the distribution of archaeological sites depends on the above geo-environmental variables. We then use the empirical relations to anticipate the potential locations of archaeological sites in a region of 980 km2 enclosing the reference site area. The model proves capable of predicting 582 sites in the larger region. Subsequent field observations there confirmed that about 80% of the model anticipations were correct. Our Archaeological Predictive Model (APM) can be scaled to larger areas and varied geographic settings, and hence can be a useful guide for archeological studies in desert regions. 相似文献
18.
Geochemical correlation of ash-fall beds with conventional tephrochronologic methods is not feasible when original glass composition is altered. Thus, alternative correlation methods may be required. Initial studies of heavily altered Paleozoic tephra (K-bentonites) have suggested the potential for employing trace-element concentrations in apatite as ash-fall bed discriminators. To further test the utility of apatite trace-element tephrochronology, we analyzed apatite phenocrysts from unaltered volcanic rocks with an electron microprobe: nine samples from rocks erupted during the Quaternary and one sample from a rock erupted during the Paleogene. The resulting apatite trace-element data provide unique bed discriminators despite within-crystal variability. Each of the volcanic rocks studied possesses unique trends in Mg, Cl, Mn, Fe, Ce and Y concentrations in apatite. The results from this study establish an important tephrochronologic method that can be applied to nearly all portions of the Phanerozoic stratigraphic record and greatly assist development of an advanced timescale. In addition to establishing a fingerprint for a particular eruption, apatite chemistry provides useful information about the source magma. 相似文献
19.
The uranium content of twelve rock reference samples, five from the Canada Centre for Mineral and Energy Technology, four from the Czechoslovakian Institute of Mineral Raw Materials and three from the United States Geological Survey was determined by neutron activation followed by delayed-neutron counting. Uranium contents measured ranged from 0.20 to 560 ppm. Three of the Canadian samples have relatively well established uranium contents. Of these we agree well with two of them; our value on the third is ∼13% lower than the recommended value. Comparison of our data on the other samples with other researchers is not yet possible because (i) no determinations are yet reported on several of these samples and (ii) even when several reported values are available, the wide disparity of those values does not allow meaningful comparison. 相似文献