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1.
采用常规宝玉石鉴定方法、偏光显微镜和激光剥蚀电感耦合等离子体质谱仪对江苏省溧阳县小梅岭玉矿的软玉样品进行了测试研究,并与良渚文化庄桥坟遗址出土的软玉类玉器样品进行了对比。结果表明,溧阳软玉样品和庄桥坟遗址出土软玉类玉器样品的主要矿物组成为透闪石,但后者的w(FeOT)明显高于前者的。庄桥坟遗址出土玉器样品的δEu普遍高于溧阳软玉样品的,大部分为负异常,为轻稀土亏损型,微量元素种类多;溧阳软玉样品的δEu为负异常,为轻稀土富集型,微量元素种类少,说明两种样品应不属于同一产地或同一成因性质。良渚文化庄桥坟遗址出土玉器样品的化学成分与溧阳软玉样品的不同,这与当今考古界普遍认为良渚文化玉器来源于溧阳软玉的观点有所不同。  相似文献   

2.
This study reports the results of twelve trace elements in twenty-seven International geochemical reference samples (IGRS) (15 from Japan, 7 from South Africa, 4 from France and 1 from U.S.A.). Similarly, ten major elements were also determined in twenty-three GRS (15 from Japan, 5 from South Africa, 2 from France and 1 from U.S.A.). Whenever possible, the results are compared with literature values for these GRS.  相似文献   

3.
Amber from the Cretaceous and Tertiary periods in North America is characterized for the first time by nuclear magnetic resonance spectroscopy. Cretaceous samples from Cedar Lake in western Canada have nearly identical spectra to samples from New Jersey. There also are strong similarities between the spectra of these samples and those from Alaska and from the state of Washington. Tertiary samples from Arkansas, on the other hand, have quite distinct spectra. A common or similar paleobotanical origin is suggested for amber from diverse locations in North America, but amber also was produced from other, quite distinct trees as from Arkansas.  相似文献   

4.
采用场发射扫描电子显微镜(FE-SEM)系统对产自新疆和田的软玉样品的主要矿物组成、化学成分、显微结构等进行了较详细的研究,并与产自中国青海、辽宁、河南及韩国的软玉样品进行了比较。结果表明,各产地软玉样品的矿物组成、化学成分和显微结构有一定的差异。和田软玉样品中含有镁质绿泥石,而辽宁软玉样品中含有较多的闪锌矿,青海软玉样品中有含Zr元素矿物的颗粒,河南软玉样品中有含La与Ce元素较高矿物的颗粒;对纯度较高的软玉样品,仅依靠主成分很难区分其产地,但依靠其微量元素成分却能起到较好的鉴别作用;和田软玉样品中透闪石的显微结构较致密,纤维尺寸要小于其它产地软玉样品的。以上信息对确定软玉的产地具有较好的参考意义。  相似文献   

5.
哈得逊与轮南地区原油碳同位素特征及影响因素   总被引:2,自引:0,他引:2  
轮南地区与哈得逊地区20个原油的全油碳同位素和正构烷烃单体烃碳同位素的分析结果表明:轮南地区原油的全油碳同位素均大于-32‰,而哈得逊地区原油的全油碳同位素一般小于-32‰;原油正构烷烃单体烃碳同位素也表现出轮南地区重于哈得逊地区的特征。两地区原油碳同位素的这种特征是由于两地区油气成藏过程的差异造成的,轮南地区原油碳同位素比哈得逊地区的原油碳同位素重的主要原因是由于来源于寒武系降解原油的混入,而非油源不同造成的。  相似文献   

6.
拜仁达坝和维拉斯托是近年来在内蒙古东部地区发现的2个大型银多金属矿床,文章对其开展了硫和铅同位素研究。结果表明,拜仁达坝矿床矿石中硫化物的δ34S值为-4.0‰~+1.6‰,维拉斯托矿床矿石中硫化物的δ34S值为-0.8‰~+2.0‰,与岩浆热液型矿床的硫同位素值接近,表明这2个矿床中的硫主要来自岩浆。拜仁达坝矿区43件金属硫化物的206Pb/204Pb值为18.333~18.515,207Pb/204Pb值为15.532~15.656,208Pb/204Pb值为38.057~38.610;维拉斯托矿区20件金属硫化物的206Pb/204Pb值为18.304~18.377,207Pb/204Pb值为15.520~15.610,208Pb/204Pb值为38.112~38.435。拜仁达坝东矿区矿石中的铅同位素组成与维拉斯托矿区相似,变化范围小,相对贫放射性铅同位素,并且均为混合铅。矿石中的铅可能来自围岩地层及深源岩浆。  相似文献   

7.
New lead isotopic compositions have been measured for Paleozoic bedded and vein ore deposits of Europe by the high precision thermal emission (triple filament) technique. Eleven samples have been analyzed from the Upper Permian Kupferschiefer bed with representatives from Poland to England, three samples from the Middle Devonian Rammelsberg deposit and one from the Middle Devonian Meggen deposit, both of which are conformable ore lenses and are in the Federal Republic of Germany (FRG); and also two vein deposits from the FRG were analyzed, from Ramsbeck in Devonian host rocks and from Grund in Carboniferous host rocks. For Kupferschiefer bed samples from Germany, the mineralization is of variable lead isotopic composition and appears to have been derived about 250 m.y. ago from 1700 m.y. old sources, or detritus of this age, in Paleozoic sedimentary rocks. Samples from England, Holland, and Poland have different isotopic characteristics from the German samples, indicative of significantly different source material (perhaps older). The isotopic variability of the samples from the Kupferschiefer bed in Germany probably favors the lead containing waters coming from shoreward (where poor mixing is to be expected) rather than basinward (where better mixing is likely) directions. The data thus support the interpretation of the metal source already given by Wedepohl in 1964. Data on samples from Rammelsberg and Meggen tend to be slightly less radiogenic than for the Kupferschiefer, about the amount expected if the leads were all derived from the same source material but 100 to 150 m.y. apart in time. The vein galena from Ramsbeck is similar to that from Rammelsberg conformable ore lenses, both in rocks of Devonian age; vein galena from Grund in Upper Carboniferous country rocks is similar to some bedded Kupferschiefer mineralization in Permian rocks, as if the lead composition was formed at about the same time and from similar source material as the bedded deposits. Although heat has played a more significant role in the formation of some of these deposits (veins and Rammelsberg-Meggen) than in others (Kupferschiefer), there is no indication of radically different sources for the lead, all apparently coming from sedimentary source material containing Precambrian detritus. One feldspar lead sample from the Brocken-Oker Granite is not the same in isotopic composition as any of the ores analyzed.Publication authorized by the Director, U.S. Geological Survey  相似文献   

8.
We report U-Pb crystallization ages from four metavolcanic rocks and two granitic gneiss samples as well as whole-rock chemical analyses and Sm-Nd isotopic ratios from 25 metaigneous and metasedimentary rocks from the Chopawamsic and Milton terranes, southern Appalachian Orogen. A metarhyolite sample from the Chopawamsic Formation and a metabasalt sample from the Ta River Formation in the Chopawamsic terrane have indistinguishable U-Pb crystallization ages of 471.4+/-1.3 Ma and 470.0+1.3/-1.5 Ma, respectively. A sample from the Prospect granite that intruded metavolcanic rocks of the Ta River Formation yields a younger U-Pb date of 458.0+/-1 Ma. Metarhyolite and granitic gneiss samples from the northern part of the Milton terrane yield U-Pb dates of 458.5+3.8/-1.0 Ma and 450+/-1.8 Ma, respectively. Metavolcanic and metaplutonic rocks from both terranes span a range in major element composition from basalt to rhyolite. Trace element concentrations in these samples show enrichment in large-ion lithophile elements K, Ba, and Rb and depletion in high field strength elements Ti and Nb, similar to those from island arc volcanic rocks. Initial epsilon(Nd) values and T(DM) ages of the metaigneous and metasedimentary samples range from 0.2 to -7.2 and from 1200 to 1700 Ma for the Chopawamsic terrane and from 3.7 to -7.2 and from 850 to 1650 Ma for the Milton terrane. The crystallization ages for the metavolcanic and metaplutonic samples from both terranes indicate that Ordovician magmatism occurred in both. Similar epsilon(Nd) values from representative samples from both terranes suggest that both were generated from an isotopically similar source. Xenocrystic zircons from metavolcanic rocks in the Chopawamsic terrane have predominately Mesoproterozoic (207)Pb/(206)Pb ages (600-1300 Ma), but a single Archean (2.56 Ga) core was also present. The xenocrystic zircons and the generally negative epsilon(Nd) values indicate that both terranes are composed of isotopically evolved continental crust.  相似文献   

9.
封闭体系有机质与有机碳氢氮恢复动力学研究   总被引:3,自引:0,他引:3  
在封闭体系的条件下,对典型的Ⅰ、Ⅱ、Ⅲ型干酪根在热演化过程中的损失进行生烃动力学研究,获得了Ⅰ、Ⅱ、Ⅲ型干酪根的总量、有机碳、氢以及氮质量损失动力学参数。用Kinetics软件计算了封闭体系干酪根有机碳丰度、氢碳原子比和氮碳原子比的恢复系数。认为在对高成熟—过成熟干酪根进行生烃评价时,Ⅰ、Ⅲ型干酪根残余有机碳丰度需要进行恢复,而Ⅱ型干酪根残余有机碳丰度不需要恢复。三种类型干酪根的氢碳原子比均需要进行恢复。  相似文献   

10.
This study aimed at determining the concentrations of trace elements in the groundwater of Abakaliki urban and some abandoned mine sites in the Southern part. Sixteen trace elements were analyzed for each of the twenty water samples collected. Laboratory results showed that the concentration of manganese varied from 4.816 to 11.238 ppm, zinc from 0.126 to 1.403 ppm, copper from 0.198 to 0.967 ppm, lead from 0.005 to 0.010 ppm, arsenic from 0.001 to 0.009 ppm, chromium from 0.009 to 0.025 mg/l, cadmium from 0.003 to 0.011 mg/l, mercury from 0.001 to 0.005 mg/l, nickel from 0.008 to 0.032 mg/l, selenium from 0.001 to 0.011 ppm, iodine from 0.013 to 0.050 ppm, uranium from 0.001 to 0.006 ppm, platinum from 0.009 to 0.032 ppm, tin from 0.014 to 0.015 ppm, lithium from 0.009 to 0.024 mg/l, cobalt from 0.015 to 0.036 mg/l, and iron from 0.010 to 0.980 ppm. These results were analyzed statistically and their distribution modeled using a software package. The results were also compared with world standards for potable water. The comparison showed that water samples are contaminated with trace elements and particularly polluted with, Mn, Hg, and Cd with average concentration values of 8.43, 0.002, and 0.005 mg/l, all above the World Health Organization standard limits of 0.005, 0.001 and 0.003 mg/l, respectively. Concentrations of Fe, Zn, and Ni are above the permissible limits of 0.30, 0.01, and 0.02 mg/l, respectively, in some places. Health hazards like metal poisoning which can result from pollution of this nature cannot be ruled out. Controlling processes such as chemical dissolutions, mechanical weathering and pollution from urban sewage, release the trace elements to the soil system while chemical dilution, otherwise called leaching, streamlines the trace element plumes to the groundwater regime with dispersion processes mixing and spreading the plume. Dispersion trends of the elements show point sources from the southern part, indicating presence of ore deposits, most likely sulfide ores as interpreted from correlation matrix.  相似文献   

11.
萨瓦亚尔顿金矿床成矿物质来源的初步探讨   总被引:1,自引:1,他引:1  
杨耘 《新疆地质》2001,19(4):271-275
萨瓦亚尔顿金矿床成矿物质具有多源性。资料显示,主成矿元素金一部分来自矿区容矿地层,另一部分来自下伏地层,矿质S和C主要来自深部,特别是下伏火山岩;Pb来自于造山带。成矿溶液主要来自以大气降水为补给的地下(卤)水。  相似文献   

12.
原油二次裂解气——天然气重要的生成途径   总被引:41,自引:3,他引:38  
赵孟军  卢双舫 《地质论评》2000,46(6):645-650
本文通过模拟实验,结合塔里木盆地塔中北斜坡地区包括有机质成油、有机质成气及原油二次裂解成气在内的生烃剖面,说明原油二次裂解成气的门限深于干酪根初次裂解成气门限。原油二次裂解生成的天然气与干酪根初次裂解生成的天然气在组分特征和碳同位素特征上存在明显的差异。一些以原油二次裂解气为主要气源所形成气藏的实例,表明原油二次裂解气可以作为特殊的重要的天然气来源。  相似文献   

13.
The Late Triassic Rhaetian stage is perhaps best known in south-west Britain for the bone beds of the Westbury Formation, but there are other fossil-rich horizons within this and the underlying Blue Anchor Formation. Samples from a borehole drilled at the Filton West Chord, and collected from exposures near Bristol Parkway railway station, have yielded significant fossil material from both of these formations. The assemblage recovered from the Blue Anchor Formation is similar to those from the lower Westbury Formation, yielding roughly equal proportions of chondrichthyans and osteichthyans. Assemblages recovered from the Westbury Formation are typical of those from the upper Westbury Formation, in being dominated by osteichthyans. The borehole samples have produced the first recorded evidence of crinoids in the British Triassic, and the first evidence of coleoid cephalopods, in the form of grasping hooklets, from the Rhaetian, and indeed the first from the British Triassic.  相似文献   

14.
应力波在平台-桩系统中传播的实验研究   总被引:5,自引:0,他引:5  
分析了应力波在平台-桩系统中的传播图案。对有限尺寸的平台来说,应力波在平台边界面上会发生反射,反射波不仅有同类波同时还有转换波,除此之外,平台表面的响应还受桩及桩土相互作用的影响。除非桩身反射波走时较长,可以避开平台上的各种干扰波,否则,由平台实测波形特征来分析平台下桩的完整性是很困难的。通过对平台上完整桩实测波形与异常桩波形进行比较,可以提高波形识别的准确度,此外,根据桩侧面测点及平台表面测点走时,相位、幅值间关系,将两者信号进行比较,可以从复杂的信号中辨别出桩身反射波信号。  相似文献   

15.
The small, burrowing, edwardsiid sea anemone Nematostella vectensis is widely distributed in estuaries and bays. Most typically it occurs in pools in marshes though it may occur subtidally as well. We have compiled records of its occurrence in North America from Nova Scotia to Georgia along the shores of the Atlantic Ocean, from Florida to Louisiana in the Gulf of Mexico and from California to Washington on the Pacific coast. To date we have found no records of its presence in Alabama or Texas, though it is present in all other of the contiguous coastal states of the United States. The species also occurs in England. We have obtained living specimens from many locations and have crossed females from England, Maryland, Georgia, California, Oregon, and Washington with males from Nova Scotia, Maryland, Georgia, and Oregon. These 24 crosses all yielded viable first-generation anemones that in turn produced second-generation animals. We accept this as proof that this widely distributed anemone is a single species. We have obtained living N. vectensis from 11 areas. Of these, only samples from Maine, Maryland, Georgia, and Oregon contained both sexes. The sample from Nova Scotia was all male and our samples from England, New Hampshire, California, and Washington were all female. We hypothesize that the unisexual samples were from clones resulting from asexual reproduction in this species. *** DIRECT SUPPORT *** A01BY066 00015  相似文献   

16.
The morphology and chemical composition of garnets from principal deposits in China and in the Arkhangelsk Province consisting of kimberlites of various mineral types have been examined. The morphology of garnets (300 specimens) from the V. Grib pipe was examined, in which crystal fragments and irregular grains predominate, and dissolution traces are common. Distribution of types of garnet coloration is typical of kimberlites: lilac-violet and red garnets of ultramafic rock association are preponderant, and the proportion of yellow-orange garnets is rather high, while brown garnets are very rare. The garnet preservation degree is very low, which is related to their high primary fracturing due to cataclasis. Grains with finely matted surfaces are preponderant (90%) reflecting their high corrosion alterations. The chemical composition was determined in 56 garnet speciments from the Grib pipe. Garnets from lherzolitic and eclogitic rock types were found and garnets from magnesium and ilmenite ultramafics are present; there are no garnets from eclogites, but garnets from diamondiferous rock associations occur. The investigations demonstrated that garnets from lherzolite rock association are preponderant in kimberlites from China, as well as from other regions, while garnets from the harzburgite-dunite and from diamondiferous rock associations are rare. Garnets belonging to the graphitepyrope depth facies were also found.  相似文献   

17.
To identify the weathering intensity and to deduce the provenance of sediments (black-brown soil and loess) from the loess tableland in the Liyang Plain is of great importance for understanding the development and origin of civilization of this critical region in China. The geochemical results show similar REE distribution patterns among sediments sampled from the YC profile in the Liyang Plain, reticulated red soils from the Dongting lake area, Xiashu loess in Zhenjiang, and loess from the Loess Plateau in China. These similarities imply a single provenance, from dust storms. REEs, especially the LREE/HREE ratio and Eu anomaly, can trace weathering intensity. Higher LREE/HREE ratios, and remarkably Eu anomalies, are present in the top loess (L0), Lower LREE/HREE ratios and insignificant Eu anomalies are present in black-brown soil (S0*) from the Liyang Plain. These demonstrate that the black-brown soils have undergone a lower intensity of weathering than the loess of YC profile. Moreover, CIA values for sediments from the YC profile provide powerful evidence to support the above result. Comparisons of analyses of the REE contents of sediments from the YC profile, of reticulated red soils from the Dongting Lake area, Xiashu loess from the Yangtze River, and loess from the Loess Plateau, clearly show the weathering intensity decreases according to the following sequence: reticulated red soil from the Dongting Lake area > sediments of YC profile from the Liyang Plain, which formed from dust storms ≈ Xiashu loess from lower reach of the Yangtze River > loess from the Loess Plateau.  相似文献   

18.
近几十年来黑河野牛沟流域的冰川变化   总被引:23,自引:12,他引:11  
阳勇  陈仁升  吉喜斌 《冰川冻土》2007,29(1):100-106
利用1956年航测、1970/1973年1:50000地形图以及野牛沟流域2003年ASTER影像获取的3期冰川资料,对黑河源头西支野牛沟流域的冰川时空变化进行了分析.通过分析流域气温变化和冰川变化的关系,探讨了流域冰川变化对河川径流的影响.结果表明:野牛沟流域1956—1970/1973年冰川总面积减少9.29%,年平均消退0.54%;1970/1973—2003年冰川总面积减少了18.23%,年平均消退0.60%.流域内冰川条数由1956年的165条减少为2003年的144条,1956—1970/1973年间流域冰川储量减少了2.29×108m3,年均损失约0.13×108m3;从1970/1973年到2003年,冰川储量减少了4.19×108m3,年均损失约0.14×108m3.从1956年到2003年,冰川变化率随着冰川面积的增加而降低,冰川萎缩速度有加快的迹象,而流域年平均温度也有加快升高的趋势.冰川的消退对于流域径流量的影响不大.  相似文献   

19.
Six oils and seven suspected source rocks from the Jianghan saline basin, in the central eastern part of China, have been examined using a variety of geochemical techniques. The results from this study show that oils from the third and fourth sections of the Qianjiang Formation (Eocene) are derived from similar source materials but have a different source from the oils of Xingouzui Formation (Eocene) in the same basin. The oils of the Xingouzui Formation (Eocene) are more mature, and probably have a greater input of terrigenous source material and in all probability have migrated greater distances than the Qianjiang oils. Oils from these sections are derived from an environment characterized as being extremely anoxic, strongly reducing and highly saline. The suspected source rocks examined in the study were from the Qianjiang Formation and were generally mature, except for the shallowest sample. The biomarker distributions in the suspected source rocks examined from the Qianjiang Formation were very different from those of the oils present in the same sections. It is proposed that oils from the Qianjiang Formation have sources in addition to, or exclusive of, the suspected source rocks examined in this study.  相似文献   

20.
卡塔克隆起中1井储层沥青地球化学特征与成因   总被引:1,自引:0,他引:1  
塔里木盆地海相原油的成因至今仍有争议,而对储层沥青的地球化学特征剖析,能为探索海相原油的成因提供依据。选取卡塔克隆起上的中1井不同层系储层沥青,详尽剖析了其地球化学特征。研究结果揭示,中1井储层沥青的Pr/Ph为1.14~1.39,CPI值 1.01~1.08,OEP值0.98~1.05,无奇偶优势或偶奇优势,伽玛蜡烷、C28甾烷丰度低,硫芴系列丰富。甾烷成熟度参数和Ts/(Ts+Tm)均指示中1井储层沥青处于成熟—高成熟热演化范畴。依据特征生物标志物的分布对沥青的成因示踪,中1井储层沥青与上奥陶统烃源岩有成因关系,而中1井储层沥青与塔东2井寒武系原油分子特征的迥异也佐证该认识。  相似文献   

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