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991.
山东省曹县地区土壤地球化学调查是按浅层土壤样品1点/4 km~2,深层土壤样品1点/16 km~2。测试N,P,K,Cu,Zn,B,Mo,Mn,F,As,Hg,Pb,Cr,Cd等14种指标。在统计这些指标的表层、深层土壤地球化学特征参数的基础上,对其与世界、全省同类参数的差异进行了分析,并分析了区内表层、深层土壤元素含量的相关性,认为该区表层土壤元素含量的显著特征是高F而低P,Zn,Mo。大部分元素在表层土壤中的含量继承了土壤母质的成分特征,但N,P,F,Hg等受人为活动和污染源的作用在表层土壤中明显富集。  相似文献   
992.
通过对刘家堡子-狼洞沟金银矿床地质、成矿元素和同位素地球化学特征的分析和研究,发现矿区内近EW向和NE向断裂构造是主要容矿构造;最佳找矿元素前缘晕组合为As-Sb-Zn,矿上晕元素组合为Au-Ag-Pb-Hg,尾晕元素组合为Ni-Cu-Co;成矿作用中,古老基底中元古宙老岭群变质岩系为成矿提供了丰富的物质来源,而燕山期构造岩浆活动在提供成矿物质的同时还提供了热动力。刘家堡子-狼洞沟金银矿床应划属为与燕山晚期超浅成中酸性岩浆岩有关的中低温热液构造裂隙充填型金银矿床。  相似文献   
993.
西南王金矿床位于栖霞-蓬莱成矿带内,是蓬莱地区西部比较典型的缓倾斜薄层石英脉型金矿床。矿体受NNE—NE向断裂控制,倾向SE,倾角15°~25°,呈薄层脉状,分布于郭家岭序列罗家单元的斑状中粒含黑云二长花岗岩和谭格庄序列牟家单元的片麻状细粒奥长花岗岩中。该文通过对矿床地质特征与矿体空间赋存规律的研究,认为矿床深部及周边区域仍有较好的资源前景。  相似文献   
994.
The unconventional oil and gas resources presented in oil shales have meant these potential sources of hydrocarbons,which has become a research focus. China contains abundant oil shale resources,ranking fourth in the world,with ca. 7 254. 48 × 10~8 t within 24 provinces,including 48 basins and 81 oil shale deposits. About 48% of the total oil shale resources are concentrated in the eastern resource region,with a further 22% in the central resource region. 65% of the total quantity of oil shale resources is present at depths of 0-500 m,with 17% of the total resources being defined as high-quality oil shales yielding more than 10% oil by weight.Chinese oil shale resources are generally hosted by Mesozoic sediments that account for 78% of the total resources. In terms of the geographical distribution of these resources,some 45% are located in plain regions,and different oil shale basins have various characteristics. The oil shale resources in China represent a highly prospective future source of hydrocarbons. These resources having potential use not only in power generation and oil refining but also in agriculture,metal and chemical productions,and environmental protection.  相似文献   
995.
根据近年来激光烧蚀电感耦合等离子体质谱仪锡石微区原位U-Pb同位素定年的实验结果,结合相关资料,对实验过程中普通铅扣除的2种主要方法,即谐和图法和等时线法的原理、效果、优点和局限性进行了深入的比较。研究成果表明,2种主要方法各有不同的优点及局限性。在实际工作中,要想获得比较准确的测试结果,需要根据具体矿物样品的年龄范围、总的U和Pb含量、普通铅相对含量、测年精度要求等因素,灵活地选择普通铅扣除的方法。  相似文献   
996.
大兴安岭北段西部新巴尔虎右旗地区新厘定出非正式填图单元——上侏罗统哈日陶勒盖玄武岩,其岩石组合为灰黑色、深绿灰色、紫褐色玄武岩以及气孔杏仁状玄武岩、碱性橄榄玄武岩、玄武粗安岩等。锆石SHRIMP U Pb定年法测得其年龄数据为(1467±31) Ma,时代为晚侏罗世。岩石地球化学分析显示,哈日陶勒盖玄武岩属高钾钙碱性系列,岩石中Sr含量低,富集大离子亲石元素Rb、K、Ba,亏损高场强元素Nb、Ti,稀土元素含量总体较高,轻重稀土分馏明显,略具有铕负异常。上侏罗统哈日陶勒盖玄武岩的厘定说明,大兴安岭地区存在晚侏罗世基性火山岩浆活动事件。通过区域地质调查和地层对比,上侏罗统哈日陶勒盖玄武岩与上侏罗统伊列克得组原始定义相符,二者实则为同物异名,建议恢复上侏罗统伊列克得组。这一认识对大兴安岭中生代构造岩浆活动的研究及中生代火山岩地层划分对比具有重要地质意义。  相似文献   
997.
北京下苇甸剖面张夏组鲕粒特征及其白云化机制   总被引:1,自引:0,他引:1  
北京下苇甸剖面张夏组作为华北寒武系的标准剖面之一,鲜有人对其中的鲕粒类型及其成岩作用进行细致研究。在充分调研前人研究的基础上,通过野外观察、实测,并结合室内薄片鉴定、XRD测试等技术,对下苇甸剖面张夏组的鲕粒类型进行总结,并对鲕粒白云化机制进行分析。结果显示:(1)下苇甸张夏组鲕粒类型主要为放射鲕、同心放射鲕及单晶鲕/多晶鲕,还有少量同心鲕、复鲕及藻鲕;(2)鲕粒发生白云化,填隙物未见白云化,且放射圈层白云化程度高于同心圈层,并且放射圈层白云石颗粒围绕核心呈放射状分布,同心圈层围绕核心呈同心状分布;(3)鲕粒内部白云石颗粒多为中细晶,自形-半自形,回流渗透白云化是造成鲕粒白云化的主要成因,因此造成亮晶鲕粒石灰岩白云化程度高于灰泥鲕粒石灰岩。  相似文献   
998.
渝东北巫山地区是重要的页岩气勘探远景区,勘探程度较低。本次研究以岩石物理和测井数据为基础,以广域电磁法为手段,开展该区的页岩气有利区评价。通过对地表样品及井孔电阻率测井资料的分析,揭示研究区目的层富有机质页岩层电阻率表现为明显低阻特征,与上覆下伏地层电性差异明显,表明本区分布的上奥陶统五峰—下志留统龙马溪组富有机质页岩具备开展电法勘探工作的物性条件。在对电磁资料处理解释的基础上,查明了重庆巫山地区"隆凹相间"的构造格局,断裂性质主要为逆断层;目的层上奥陶统五峰组—下志留统龙马溪组富有机质泥页岩连续稳定分布,低阻特征明显,埋深范围在800~4 800 m之间。综合考虑目的层页岩电阻率、极化率、埋深等因素,预测出页岩气有利区3个,区内富有机质页岩发育,页岩气勘探前景较好。  相似文献   
999.
This work restored the erosion thickness of the top surface of each Cretaceous formations penetrated by the typical well in the Hari sag, and simulated the subsidence burial history of this well with software BasinMod. It is firstly pointed out that the tectonic subsidence evolution of the Hari sag since the Cretaceous can be divided into four phases: initial subsidence phase, rapid subsidence phase,uplift and erosion phase, and stable slow subsidence phase. A detailed reconstruction of the tectonothermal evolution and hydrocarbon generation histories of typical well was undertaken using the EASY R_0% model, which is constrained by vitrinite reflectance(R_0) and homogenization temperatures of fluid inclusions. In the rapid subsidence phase, the peak period of hydrocarbon generation was reached at c.a.105.59 Ma with the increasing thermal evolution degree. A concomitant rapid increase in paleotemperatures occurred and reached a maximum geothermal gradient of about 43-45℃/km. The main hydrocarbon generation period ensued around 105.59-80.00 Ma and the greatest buried depth of the Hari sag was reached at c.a. 80.00 Ma, when the maximum paleo-temperature was over 180℃.Subsequently, the sag entered an uplift and erosion phase followed by a stable slow subsidence phase during which the temperature gradient, thermal evolution, and hydrocarbon generation decreased gradually. The hydrocarbon accumulation period was discussed based on homogenization temperatures of inclusions and it is believed that two periods of rapid hydrocarbon accumulation events occurred during the Cretaceous rapid subsidence phase. The first accumulation period observed in the Bayingebi Formation(K_1 b) occurred primarily around 105.59-103.50 Ma with temperatures of 125-150℃. The second accumulation period observed in the Suhongtu Formation(K_1 s) occurred primarily around84.00-80.00 Ma with temperatures of 120-130℃. The second is the major accumulation period, and the accumulation mainly occurred in the Late Cretaceous. The hydrocarbon accumulation process was comprehensively controlled by tectono-thermal evolution and hydrocarbon generation history. During the rapid subsidence phase, the paleo temperature and geothermal gradient increased rapidly and resulted in increasing thermal evolution extending into the peak period of hydrocarbon generation,which is the key reason for hydrocarbon filling and accumulation.  相似文献   
1000.
The Sidingheishan mafic-ultramafic intrusion is located in the eastern part of the Northern Tianshan Mountain, along the southern margin of the Central Asian Orogenic Belt in northern Xinjiang autonomous region of China. The Sidingheishan intrusion is mainly composed of wehrlite, olivine websterite, olivine gabbro, gabbro and hornblende gabbro. At least two pulses of magma were involved in the formation of the intrusion. The first pulse of magma produced an olivine-free unit and the second pulse produced an olivine-bearing unit. The magmas intruded the Devonian granites and granodiorites.An age of 351.4±5.8 Ma(Early Carboniferous) for the Sidingheishan intrusion has been determined by U-Pb SHRIMP analysis of zircon grains separated from the olivine gabbro unit. A U-Pb age of 359.2±6.4 Ma from the gabbro unit has been obtained by LA-ICP-MS. Olivine of the Sidingheishan intrusion reaches 82.52 mole% Fo and 1414 ppm Ni. On the basis of olivine-liquid equilibria, it has been calculated that the MgO and FeO included in the parental magma of a wehrlite sample were approximately10.43 wt% and 13.14 wt%, respectively. The Sidingheishan intrusive rocks are characterized by moderate enrichments in Th and Sm, slight enrichments in light REE, and depletions in Nb, Ta, Zr and Hf. The ε_(Nd)(t) values in the rock units vary from +6.70 to +9.64, and initial ~(87)Sr/~(86)Sr ratios range between 0.7035 and0.7042. Initial ~(206)Pb/~(204)Pb, ~(207)Pb/~(204)Pb and ~(208)Pb/~(204)Pb values fall in the ranges of 17.23-17.91,15.45-15.54 and 37.54-38.09 respectively. These characteristics are collectively similar to the Heishan intrusion and the Early Carboniferous subduction related volcanic rocks in the Santanghu Basin, North Tianshan and Beishan area. The low(La/Gd)_(PM) values between 0.26 and 1.77 indicate that the magma of the Sidingheishan intrusion was most likely derived from a depleted spinel-peridotite mantle.(Th/Nb)_(PM)ratios from 0.59 to 20.25 indicate contamination of the parental magma in the upper crust.Crystallization modeling methods suggest that the parental magma of the Sidingheishan intrusion was generated by flush melting of the asthenosphere and subsequently there was about 10 vol%contamination from a granitic melt. This was followed by about 5 vol% assimilation of upper crustal rocks. Thus, the high-Mg basaltic parental magma of Sidingheishan intrusion is interpreted to have formed from partial melting of the asthenosphere during the break-off of a subducted slab.  相似文献   
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