中甸地区甭哥正长岩地球化学特征及其地质意义   总被引：4，自引：0，他引：4  

曹殿华王安建  修群业杨岳清 李瑞萍 《地质学报》2007,81(7):995-1003

长期以来,甭哥正长岩体被认为是印度—欧亚板块碰撞引起的走滑剪切构造所控制的碱性岩浆活动的产物。本文研究表明甭哥正长岩属钾玄岩系列,富集K2O（5.88%~9.08%）、稀土元素（特别是轻稀土元素）和大离子亲石元素,高场强元素亏损,具有岛弧型微量元素特征。地球化学数据表明原岩于高压条件下发生部分熔融,岩浆源区深度较大,经历了结晶分异作用形成正长岩岩浆。甭哥正长岩的锆石稀释法U-Pb测定年龄为201.4Ma,略晚于中甸弧钙碱性斑岩,其形成的构造环境是弧后拉张环境,甘孜—理塘洋向西低角度俯冲使中甸地区地壳挤压增厚,从而在较深的深度形成原始岩浆。在中甸岛弧岩浆演化后期存在区域性的构造体制转折,从区域性的挤压环境转换成区域性的拉张环境,甭哥岩体的侵位处于两者的过渡时期。  相似文献   

八宝山煤矿北部正长斑岩岩体的产状及其意义     

范和平  张树胜  吴顺福 《煤田地质与勘探》1999,27(5):13-15

从岩体的岩性、时代、产状等方面,论证了八宝山煤矿北部的正长斑岩体为一岩盖,下部找煤前景可观,可在井下实施巷探和定向钻探找煤,以延长矿井寿命   相似文献   

皖西霞石正长岩合成沸石分子筛及提钾的实验研究   总被引：22，自引：4，他引：18  

杨静  马鸿文  王英滨  戚洪彬 《现代地质》2000,14(2):153-157

合成沸石因具有优异的吸附及离子交换性能而备受关注。本实验以皖西地区霞石正长岩为主要原料 ,成功地合成了 13 X型沸石分子筛 ,母液经蒸发、分离 ,制得了白炭黑及碳酸钾 ,表明霞石正长岩具有巨大的潜在综合利用价值。合成沸石、白炭黑和碳酸钾的成分、结构及性能分析表明 ,3种产品均达到了国家或化工行业标准。基于此 ,对工艺技术可行性作了分析评价  相似文献   

东坪式金矿床铅同位素组成特征及其化探评价   总被引：2，自引：0，他引：2  

包志伟  赵振华  张佩华  王一先 《地球化学》2000,29(3):223-230

东坪式金矿床产于华北克拉通化缘深大断裂－－尚义－赤城断裂的南侧,海西期水泉沟正长岩杂岩体内外接触带。矿体具有明显的分层笥,自上而下矿石类型由石英脉型向钾、硅化蚀变岩型过渡。矿床形成于燕山早期,成矿物质主要来源于正长岩杂岩体。矿石铅同位素组成与正长岩杂岩体相似,在＾２０７Ｐｂ／＾２０６Ｐｂ－＾２０８Ｐｂ／＾２０６Ｐｂ图解上,矿石、正长岩、矿石中的钾长石脉石及太古宇桑干群变质岩呈线性分布,矿石与正长岩  相似文献   

广东恶鸡脑碱性正长岩的地球化学及其地球动力学意义   总被引：34，自引：3，他引：31  

包志伟  赵振华  熊小林 《地球化学》2000,29(5):462-468

广东从化恶鸡脑碱性正长岩岩体是广东乃至华南地区唯一已各的中生代含副长石及碱性暗色矿物的碱性正长岩岩体。岩石含有霞石、白榴石及岩浆成因的方钠石。碱性正长岩体侵入到燕山期第三期的佛冈岩体之中,岩体侵位年龄为１２７．５Ｍａ（角闪石Ａｒ￣Ａｒ法）。岩体富大离子亲石元素,贫Ｓｒ和Ｂａ,具有明显的铕负异常,富Ｎｂ和Ｚｒ等高场强元素。εＥｄ（ｔ）为近于零的负值（－０．６６￣－１．６）,模式年龄ｔＤＭ较小（０．９  相似文献   

Origin of the Late Cretaceous syenite from Yandangshan,SE China,constrained by zircon U–Pb and Hf isotopes and geochemical data     

《International Geology Review》2012,54(6):556-582

The Yandangshan syenite is a representative Late Cretaceous igneous pluton cropping out in SE China. U–Pb zircon dating using LA‐ICP‐MS yielded a crystallization age of 98±1 Ma for the syenite. Petrographically and geochemically of shoshonitic affinity, it is enriched in LREE and LILE, and has a pronounced Nb–Ta trough in the primitive mantle‐normalized trace element spider diagram. Zircon ?_Hf(t) values vary from ?3.04 to ?7.71, displaying a unimodal distribution. The syenite also has high Sr [(⁸⁷Sr/⁸⁶Sr) _i  = 0.7086–0.7089], low Nd [?_Nd(t) = ?6.57 to ?7.64] isotopic ratios, plotting in the enriched mantle field on an ?_Nd(t) versus (⁸⁷Sr/⁸⁶Sr) _i diagram. We propose that the Yandangshan syenite was generated by pyroxene‐dominated high‐pressure fractional crystallization from basaltic magma that was derived from an enriched mantle source. Although coexisting Yandangshan rhyolites have Sr–Nd isotopic compositions similar to the Yandangshan syenite, they were not derived from the same source. Instead, the rhyolitic magma was produced by partial melting of crustal materials as a result of the underplating of basaltic magma. The crust‐like Sr–Nd–Hf isotopic signature of the Yandangshan syenite is ascribed to mantle sources that were enriched by subducted sediments. Formation of Yandangshan syenite may represent roll‐back of the subducting palaeo‐Pacific plate and migration of the arc front to the Yandangshan area at ～98 Ma.  相似文献   

豫西磨沟正长岩LA-ICP-MS锆石U-Pb年代学及Hf同位素   总被引：4，自引：0，他引：4  

卢仁  梁涛  白凤军  卢欣祥 《地质论评》2013,59(2):355-368

河南省东秦岭地区印支期岩浆活动产物零星出露,豫西外方山纸房—黄庄地区是其产地之一,本文对纸房—黄庄地区出露面积最大的磨沟正长岩岩体进行了LA-ICP-MS锆石U-Pb定年及Hf同位素测试.磨沟正长岩的锆石206 Pb/238U谐和年龄为245.5 ±8.0Ma(95%置信度,MSWD=2.6),记录了秦岭造山带印支期内早三叠世碱性岩浆活动事件.磨沟正长岩样品的εHf(t)值介于-31.89～-10.59之间,聚集于-31.89～-27.64和-21.02～-10.59两个区间内,二阶段Hf模式年龄(tDM2)为1937～3267Ma,集中于1937～ 2591 Ma和3003 ～ 3267 Ma两个年龄范围内.锆石Hf同位素特征表明磨沟正长岩是幔源碱性岩浆与壳源花岗质岩浆(片麻岩部分熔融)相混合的产物,与磨沟正长岩岩体中出现暗色微粒包体这一地质特征相吻合.磨沟正长岩形成于秦岭造山带的面接触碰撞时期,长期持续的碰撞效应使纸房—黄庄岩石圈厚度在垂向上显著增厚,其重力不稳定性加强,在印支早期发生局部小规模拆沉,与之伴有大规模的深部流体活动,暗示纸房—黄庄地区具有巨大成矿潜力,尤其是与正长岩岩体自身相关的稀有(Rb、Zr)、轻稀土元素及非水溶性钾矿资源.  相似文献   

内蒙古中部巴音勿拉山岩体的地质特征及构造意义     

王大勇  于淼  高迪  王挽琼  白新会  蒋孝君 《吉林地质》2014,(3):5-12

巴音勿拉山岩体位于华北克拉通北部,白乃庙岛弧岩带南部,锆石LA-ICP-MS U-Pb定年结果及锆石特征表明其侵位时代为(410.9±1.2)Ma。岩体岩石组合为一套正长岩杂岩,富钾富碱,铝质量分数较高,属偏铝质岩石。地球化学特征表明岩浆源区为岩石圈地幔,岩浆演化过程中下地壳的同化作用显著。其形成与白乃庙岛弧岩带与华北克拉通碰撞后的伸展作用有关。  相似文献   

http://www.sciencedirect.com/science/article/pii/S1674987113000893   总被引：1，自引：0，他引：1  

K.R. Hari  N.V. Chalapathi Rao  Vikas Swarnkar  Guiting Hou 《地学前缘(英文版)》2014,5(2):261-276

Two petrologically distinct alkali feldspar syenite bodies （AFS-1 and AFS-2） from Chhotaudepur area, Deccan Large Igneous Province are reported in the present work. AFS-1 is characterized by hypidio-morphic texture and consists of feldspar （Or55Ab43 to Or25Ab71）, ferro-pargasite/ferro-pargasite horn-blende, hastingsite, pyroxene （Wo47, En5, Fs46）, magnetite and biotite. AFS-2 exhibits panidiomorphic texture with euhedral pyroxene （Wo47-50, En22-39, Fs12e31） set in a groundmass matrix of alkali feldspar （Or99Ab0.77 to Or1.33Ab98）, titanite and magnetite. In comparison to AFS-1, higher elemental concentra-tions of Ba, Sr and PREE are observed in AFS-2. The average peralkaline index of the alkali feldspar syenites is w1 indicating their alkaline nature. Variation discrimination diagrams involving major and trace elements and their ratios demonstrate that these alkali feldspar syenites have a shoshonite affinity but emplaced in a within-plate and rifting environment. No evidence of crustal contamination is perceptible in the multi-element primitive mantle normalized diagram as well as in terms of trace elemental ratios. The enrichment of incompatible elements in the alkali feldspar syenites suggests the involvement of mantle metasomatism in their genesis.  相似文献   

Geochemical characteristics and petrogenesis of the Dashipo-Heishantuo batholith in Beijing and its geological significanceEI北大核心CSCD     

Wang Y.Jiao Y. 《大地构造与成矿学》2015,(1):139-152

The early Jurassic Dashipo-Heishantuo batholith in Beijing, which consists of the Dashipo hornblende-biotite syenite and Heishantuo granite, exposed in the western Yanshan orogenic belt, eastern North China Craton. The Dashipo syenite is magnesian potassic intermediate rock enriched in large ion lithophile elements such as Rb, Ba, Sr, Pb and LREE, and relatively depleted in high field strength elements such as Nb, Ta, U, Th, Zr, Hf as well as P and Ti, with εNd(t) values from -12.1 to -12.2 and ISr values of 0.70506-0.70464. The Heishantuo granite is magnesian peraluminous high K calc-alkaline, with an enrichment of large ion lithophile elements and radioactive elements such as Rb, Ba, Th, U and Pb, and a depletion of HREE and high field strength elements such as Nb, Ta, Zr and Hf as well as Sr, P and Ti, with εNd(t) values from -15.5 to -18.0 and ISr values of 0.70516-0.70593. The magma of the Dashipo syenite is produced by fractional crystallization of mantle-derived K-rich mafic magma under high pressure. The partial melting of the lower crust, which was heated and metasomatised by the mantle-derived magma, produced granitic magma that intruded into the unconsolidated Dashipo syenite to form the concentric batholith. The petrology and geochemistry of the Dashipo hornblende-biotite syenite indicate that the water weakening was important for the lithospheric destruction within the interior part of the North China Craton. Meanwhile, the partial melting related to the double-diffusion of energy and chemical composition between mantle-derived magma and crustal rocks was an important mechanism for the Mesozoic calc-alkaline felsic magmatism occurred in the interior of the North China Craton. ©, 2015, Science Press. All right reserved.  相似文献