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1.
内蒙古东北部东乌珠穆沁旗乌兰哈德一带晚侏罗世满克头鄂博组的地质特征及岩性段划分 总被引:1,自引:1,他引:0
根据《内蒙古1∶5万辉音敖包、达勒廷查干、固腊卜赛罕敖包、乌兰哈德农场幅区域地质调查》项目工作成果,认为出露于内蒙古东乌旗乌兰哈德一带的晚侏罗世满克头鄂博组火山机构类型为破火山,由早到晚依次发育初始爆发、大规模爆发、破火口塌陷沉积和破火山复活(为潜流纹岩)4个演化阶段,与典型破火山的演化模式基本一致。同一演化阶段的岩石组合具有整体一致的爆发强度。据此将属于地层范畴的前3个演化阶段依次划分为一、二、三段:一段为凝灰质砾岩夹沉凝灰岩;二段以流纹质熔结凝灰岩、流纹质熔结角砾凝灰岩为主,夹流纹质凝灰岩,局部夹少量流纹岩;三段为沉角砾凝灰岩夹沉凝灰岩。本划分方案标准较统一,野外易于操作,可填性强。各岩性段反映的是破火山活动的强弱特征,记录的是破火山演化阶段。岩性段的划分与火山演化历史研究等有机地结合在一起,有利于该组正确地层层序的建立和较大区域内的地层对比。 相似文献
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冀北晚侏罗世张家口组段的划分 总被引:1,自引:0,他引:1
4冀北晚侏罗世张家口组的岩石地层单位长期以来一直没有一个较统一的划分方案,划分较为混乱,影响了其合理的地层层序的建立及区域地层对比。根据《冀北中生代陆相火山-沉积盆地1∶25万填图方法研究》项目的工作成果,提出张家口组以相序的岩石组合为基本单元将其依次划分为3个岩性段的方案。一段主要为弱喷发相序的岩石组合;二段主要为爆发相序的岩石组合;三段主要为喷发沉积相序的岩石组合。三者分别代表该组某破火山的初始爆发阶段、大规模爆发阶段和破火口塌陷沉积阶段。由此划分的岩性段可以较好地反映火山构造特征,建立合理的地层层序,有助于火山演化历史的研究,使岩石地层单位的划分与火山-沉积盆地的研究有机地结合在一起。 相似文献
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冀北晚侏罗世张家口组内岩石地层单位长期以来一直没有一个较统一的划分方案,使之划分较为混乱,影响了其合理地层层序的建立及区域地层对比。笔者通过“冀北中生代陆相火山一沉积盆地1:25万填图方法研究”项目的工作,提出张家口组内以相序的岩石组合为基本单元将其依次划分3个岩性段。一段主要为弱喷发相序的岩石组合;二段主要为爆发相序的岩石组合;三段主要为喷发沉积相序的岩石组合。三者分别代表该组某破火山的初始爆发阶段、大规模爆发阶段和破火口塌陷沉积阶段。由此划分的岩性段可以较好地反映火山构造特征,建立合理的地层层序,有助于火山演化历史的研究。使岩石地层单位划分与火山-沉积盆地研究有机地结合在一起。 相似文献
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以营城组火山岩为主,利用岩心、测井、试油等资料,从岩性、岩相及物性等方面对徐家围子断陷徐东地区火山岩储层特征加以研究。徐东地区营城组火山岩储层的主要岩性为流纹岩、流纹质凝灰岩、流纹质熔结凝灰岩、流纹质角砾岩和流纹质角砾凝灰岩;火山岩相按岩性组合特征可分为火山爆发相、火山溢流相和火山沉积相;孔隙类型主要为原生孔隙的气孔、气孔被充填后的残余孔、裂缝及微裂缝和次生孔隙的长石溶蚀孔、火山灰溶蚀孔、球粒流纹岩中流纹质玻璃脱玻化产生的微孔隙、石英晶屑溶蚀孔等。通过对单井储地比、储层厚度频率分布、产能情况及成藏规律的分析研究将徐东地区分为三个储层发育带,找出了最有利的储层发育带,为下一步的勘探部署起到了一定的指导作用。 相似文献
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通过1︰5万地质填图及剖面测制,作者在粤北大瑶山地区的震旦-寒武纪地层中首次发现多层火山岩,岩性主要为火山-沉积碎屑岩类的变质凝灰质不等粒岩屑石英砂岩、变质凝灰质不等粒长石石英砂岩、沉凝灰岩等,局部见变流纹质熔结凝灰岩。对变流纹质熔结凝灰岩、变质凝灰质砂岩用LA-ICP-MS法测定锆石U-Pb年龄,206Pb/238U年龄介于614~2869 Ma之间,年龄值较为分散,说明碎屑锆石是多来源的。火山岩年龄数据与地层时代归属矛盾,粤北大瑶山地区前泥盆纪地层的时代归属值得进一步探讨。 相似文献
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赣南—粤北版石群及其地质时代 总被引:11,自引:1,他引:10
赣南—粤北中生代晚期存在上、中、下3个不同时代的火山岩系,其中上火山岩系称为版石群。根据岩性岩相特征,版石群可进一步划分为两个岩组:下岩组称为合水组,以砾岩、砂岩、页岩等沉积岩为主、夹火山岩,代表火山活动初始期的产物;上岩组称为优胜组,岩性为流纹岩、流纹质凝灰岩、熔结凝灰岩,代表火山活动喷发期的产物。长塘盆地优胜组熔结凝灰岩全岩RbSr等时线年龄为89.5Ma;仁差盆地优胜组流纹岩全岩RbSr等时线年龄为91.9~94Ma,熔结凝灰岩锆石UPb法年龄为86.5Ma,次流纹斑岩锆石UPb法年龄为93.5Ma;菖蒲盆地优胜组流纹岩全岩RbSr等时线年龄为104Ma;版石盆地优胜组流纹岩全岩RbSr等时线年龄为72.2Ma,全岩KAr法年龄为77.6Ma,可见版石群优胜组的地质时代为早白垩世晚期—晚白垩世早期。另外,合水组的生物化石反映出早白垩世的特征,因此,将版石群置于早白垩世—晚白垩世早期是可信的。 相似文献
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仙游牛头山金矿化体产于侏罗系上统南园组第二段流纹质熔结凝灰岩、流纹质凝灰岩及沉凝灰岩中。与北北东向断裂带、片理化带以及牛头山锥状火山关系密切。区内金矿化范围大,已见金矿化脉(体)12条,组成规模较大的北东、近南北向矿化带,找矿远景好。 相似文献
10.
晚白垩世石牛山组为东南沿海晚白垩世重要的沉积-火山地层,为一套陆相沉积-火山喷发岩系,其平行不整合于寨下组之上;根据地层层序、接触关系、岩石组合特征、火山活动旋回及岩浆演化规律等,将其进一步划分为2个岩性段,下段为火山碎屑沉积岩,上段为酸性火山碎屑岩夹酸性火山熔岩组合,其构成一个完整的沉积-喷发旋回.对石牛山组上段流纹... 相似文献
11.
奥地利安东帕有限公司 《岩矿测试》2009,28(3):306-306
最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提 相似文献
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Joseph Clancy White 《Contributions to Mineralogy and Petrology》1993,113(4):524-532
The textural relationships and structural states of optically isotropic labradorite from the Manicouagan, Quebec, impact structure have been examined by light (optical) and transmission electron (TEM) microscopy. Two distinct diaplectic glasses have been recognized based on their contrasting morphology, timing and the inferred modes of formation. The earliest isotropic bands and grain-scale isotropism (maskelynite) optically exhibit a gradational,in situ transformation from crystalline plagioclase with preservation of relict textures (twins, grain boundaries). The same transformation from crystalline to amorphous structure is observed in TEM to occur heterogeneously at scales on the order of the unit cell. The progressive transformation of optical properties reflects an increase in the volume fraction and eventual coalescence of these amorphous units. This maskelynite-type diaplectic glass is interpreted to form in the solid-state directly from crystalline material during the compressional phase of the shock wave. The other isotropic material occurs in spatially discrete tensiongashes and planar deformation features (PDFs) that overprint the maskelynite-type glass. This second type of diaplectic glass (PDF-type) is developed homogeneously within a given glass band and exhibits sharp crystal-glass boundaries, in contrast to the gradational boundaries of the maskelynite-type glass. PDF-type glass is interpreted to form by melting in tensional release zones during passage of the rarefaction wave. These observations emphasize the ability of naturally shocked rocks to preserve subtle evidence of variations in the shock process from highly transient events. 相似文献
13.
A catastrophic rockslide-debris flow in Wulong, Chongqing, China in 2009: background, characterization, and causes 总被引:7,自引:3,他引:4
Qiang Xu Xuanmei Fan Runqiu Huang Yueping Yin Shengshan Hou Xiujun Dong Minggao Tang 《Landslides》2010,7(1):75-87
On June 5, 2009, a catastrophic rockslide-debris flow occurred at the crest of the Jiweishan Mountain in Wulong, Chongqing,
China. Approximately five million cubic meters of limestone blocks slid along a weak interlayer of bituminous and carbonaceous
shale. The source mass descended from the upper part of the slope rapidly, crossing a 200-m wide and 50-m deep creek in front
of it. Blocked by the opposite steep creek wall, the sliding mass changed its direction and traveled a further 2.2 km along
the creek in debris-flow mode, finally forming a large accumulation zone with an average depth of 30 m. This is one of the
most catastrophic rockslide events in recent years in China. It buried 12 houses and the entrance of an iron mining tunnel
where some 27 miners were working inside. Ten people died, 64 missing, and eight wounded. Immediately after this disaster
happened, the government organized an expert team to assist the rescue work. As one of the geological experts, the author
did a lot of field investigations and collected first-hand information. Multi-methods including the remote sensing, 3D laser
scanning, geophysical exploration, and numerical modeling were used for analyzing the characteristics and the triggering mechanism
of the Wulong rockslide. The preliminary investigation results reveal that this rockslide with poor geological conditions
was mainly induced by the gravitation and the karst effect and also affected by the previous mining activities. The research
in this paper is meaningful and useful for further research on such kind of rockslides that are geologically similar to the
Wulong rockslide. 相似文献
14.
S. Viswanathan K. Surya Prakash Rao B. Mahabaleswar 《Journal of the Geological Society of India》2013,82(6):621-627
Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours. 相似文献
15.
Xiaoyu ZHAO Wuyi WANG Hairong LI Fujian FENG Lizhen WANG 《中国地球化学学报》2006,25(B08):80-81
Brick-tea-type fluorosis is a peculiar endemic disease in China, which had been discovered in minority areas of western China since 1980, and distributed mainly in Tibet, Inner Mongolia, Gansu, Xinjiang, Qinghai and parts of Sichuan Province. The prevalence rate of fluorosis in Tibetan and Mongolian nationality people was higher. Epidemiological investigation showed that fluorosis morbidity and degrees were different in different brick-tea drinking areas, and it was probably caused by drinking various kinds of brick tea from different regions. Therefore, we collected 33 samples of brick tea from six provinces where minority nationalities were accustomed to drinking a large quantity of brick tea. F concentrations were determined by the combustion hydrolysis-ion selective electrode method. The results showed that among the brick teas, the F concentrations ranged from the minimum 74.1 mg/kg in Yunnan Province to the maximum 991.2 mg/kg in Sichuan Province. Besides, there was a great difference among the various kinds of brick tea, and F concentrations decreased in the order of Kang brick tea, Green brick tea, Black brick tea, Mi brick tea, Fu brick tea, Chitsu ping tea, Puerh tea, and Tuo tea. The average F concentration in brick teas was 431.92 mg/kg. 相似文献
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L. I. Mashonkina A. B. Vinogradova D. A. Ptitsyn V. S. Khokhlova T. A. Chernetsova 《Astronomy Reports》2007,51(11):903-919
We derived Sr, Y, Zr, and Ce abundances for a sample of 74 cool dwarfs and subgiants with iron abundances, [Fe/H], between 0.25 and ?2.43. These estimates were obtained using synthetic spectra, assuming local thermodynamic equilibrium (LTE) for Y, Zr, and Ce, allowing for non-LTE conditions for Sr. We used high-resolution (λ/Δλ?40 000 and 60 000) spectra with signal-to-noise ratios between 50 and 200. We find that the Zr/Y, Sr/Y, and Sr/Zr ratios for the halo stars are the same in a wide metallicity range (?2.43 ≤ [Fe/H] ≤ ?0.90), within the errors, indicating a common origin for these elements at the epoch of halo formation. The Zr/Y ratios for thick-disk stars quickly decrease with increasing Ba abundance, indicating a lower rate of production of Zr compared to Y during active thick-disk formation. The thick-disk and halo stars display an increase in the [Zr/Ba] ratio with decreasing Ba abundance and a correlation of the Zr and Eu overabundances relative to Ba. The evolutionary behavior of the abundance ratios found for the thick-disk and halo stars does not agree with current models for the Galaxy’s chemical evolution. The abundance ratios of Y and Zr to Fe and Ba for thin-disk stars, as well as the abundance ratios within each group, are, on average, solar, though we note a slight decrease of Zr/Ba and Zr/Y with increasing Ba abundance. These results provide evidence for a dominance of asymptotic-giant-branch stars in the enrichment of the interstellar medium in heavy elements during the thin-disk epoch, in agreement with the predictions of the nucleosynthesis theory for the main s-process component. 相似文献
18.
Natural Hazards - Despite the application of various methods to calculate uncertainty in flood vulnerability assessments, the challenge of uncertainty remains. The main purpose of this study was to... 相似文献
19.
Arsenic concentrations of less than 5 ppb to as large as 1,260 ppb in stream waters and from 5 ppm to 4,000 ppm in stream
sediments were found in the Pedro Dome-Cleary Summit area, Alaska. Waters from three of 20 wells sampled had arsenic concentrations
exceeding the U.S. Public Health Service recommended limit of 50 ppb. The high arsenic levels are a consequence of arsenic
enrichment in the rocks of the area. Placer and lode-gold mining may increase the arsenic content of the waters by exposing
arsenic-containing rocks to surface waters and by increasing the load of arsenic-rich sediments in the streams. Finding these
disturbingly large concentrations of arsenic in the waters of the Fairbanks area was the major result of this work, inasmuch
as a subsequent study (to be published) revealed arsenic concentrations as large as 10 ppm in domestic wells and prompted
an extensive study by Federal and State agencies of the health hazard posed by these arsenic-rich waters. 相似文献
20.
《《地质学报》英文版》2019,(Z1)
正Over four years ago,a group of investigators came together to determine if Big Data approaches (specifically data mining,machine learning and analytics in general) might provide insight into some of the grand challenges in Earth's history:evolution of minerals,rise of oxygen,life,influence of super continental cycles,quantifying the magnitude of extinction events,and more.As a result,the team of mineralogists,petrologists,geochemists, 相似文献