攀枝花层状辉长质岩体的微量元素和锶钕铅氧同位素系统:地幔源区和矿床成因的证据   总被引：8，自引：0，他引：8  

艾羽  张招崇  王福生  郝艳丽  赵莉  杨铁铮 《地质学报》2006,80(7):995-1004

攀枝花岩体是攀西地区一个典型含钒钛磁铁矿的层状辉长质岩体,是峨眉山大火成岩省的组成部分。其Sr、Nd、Pb同位素组成变化范围较窄,落在峨眉山玄武岩的范围内,同时也落在洋岛玄武岩范围内,说明攀枝花岩体与峨眉山玄武岩有着成因联系,均与地幔柱作用有关。其低的δ18O值(<6‰)说明没有地壳物质的混染,其高的La/Nb比值(>1)和微量元素原始地幔标准化图解出现的负Nb异常则表明源区有岩石圈地幔物质的混染。因而攀枝花岩体是地幔柱和岩石圈地幔部分熔融的产物,岩浆在岩浆房中没有经历地壳物质的混染作用。Mg#与P2O5的正相关以及P2O5与FeO含量的负相关,表明P不是导致氧化物熔体不混熔的主要原因;而Mg#与Fe2O3/FeO的负相关则说明,岩浆演化过程中氧逸度的升高可能是导致氧化物熔体不混熔的主要原因。  相似文献   

攀枝花地区冰期膨胀土的工程特性研究     

寸春发  鲍峰  赵永顺  夏永华  张林洪 《工程地质学报》2011,19(2):254-261

攀枝花地区冰期膨胀土生成于二冰期晚期中更新统冰期,通过室内和现场物理力学试验和分析,揭示攀枝花地区冰期膨胀土的物理力学性质具有很大的离散性,其性质受土体的矿物成分、含水率、裂隙面、埋藏深度、级配、试验条件等因素、条件的影响.试验研究表明:膨胀土中的裂隙面按光滑程度不相同,可分为两种类型,即光滑裂隙面和光滑擦痕裂隙面;粗...  相似文献   

四川攀枝花钒钛磁铁矿床Fe同位素特征及其成因指示意义   总被引：4，自引：0，他引：4  

王世霞  朱祥坤  宋谢炎  陈列锰 《地球学报》2012,33(6):995-1004

本文系统研究了四川攀枝花含钒钛磁铁矿层状岩体全岩和矿石矿物磁铁矿的Fe同位素组成特征。研究获得全岩δ⁵⁷Fe的范围为0.02‰～0.25‰, 平均值为0.17‰, 磁铁矿的δ⁵⁷Fe范围为0.05‰～0.61‰, 平均值为0.36‰。相对于磁铁矿单矿物, 全岩Fe同位素组成变化不大。相对于全岩, 磁铁矿具有相对重的Fe同位素组成, 并且其相对偏重程度与样品中磁铁矿的含量呈反相关关系。磁铁矿Fe同位素组成与形成环境氧逸度之间的负相关关系表明磁铁矿从岩浆中结晶出来之后没有发生重力分异, 赋存于岩体和矿体中的磁铁矿是原位结晶的。磁铁矿的Fe同位素特征表明攀枝花岩体是多次岩浆补充和分离结晶共同作用的结果: 形成下部岩相带过程中, 玄武质岩浆补充频繁, 形成巨厚的块状磁铁矿层, 其中的磁铁矿的δ⁵⁷Fe值变化较小; 而形成中部岩相带过程中, 玄武质岩浆补充的频率逐渐降低, 形成多个旋回以及交替产生的磁铁辉长岩和辉长岩。同时, 形成攀枝花岩体和矿体的初始岩浆的氧逸度很高, 在高氧逸度环境下富集成矿, 演化过程中岩浆体系氧逸度逐渐降低, 很好地解释了攀枝花V-Ti磁铁矿主矿体赋存在含矿岩体下部的辉长岩中的成矿机制。  相似文献   

Abundant Fe–Ti oxide inclusions in olivine from the Panzhihua and Hongge layered intrusions, SW China: evidence for early saturation of Fe–Ti oxides in ferrobasaltic magma   总被引：1，自引：0，他引：1  

Kwan-Nang Pang  Chusi Li  Mei-Fu Zhou  Edward M. Ripley 《Contributions to Mineralogy and Petrology》2008,156(3):307-321

Abundant Fe–Ti oxide inclusions in cumulus olivine (Fo_77–81) from the Panzhihua and Hongge intrusions, Emeishan large igneous province, SW China, document the first evidence for early crystallization of Fe–Ti oxides in ferrobasaltic systems in nature. The intrusions also contain significant stratiform Fe–Ti–V oxide ores. The oxide inclusions are sub-rounded or irregular, range from ∼5 to 50 μm in diameter, and are dominated by either titanomagnetite or ilmenite. The fact that the inclusions are either titanomagnetite- or ilmenite-dominant suggests that they are trapped crystals, instead of immiscible oxide melt, formed during growth of the host olivine. The absence of other silicate phases in the inclusion-bearing olivine is difficult to reconcile with a possible xenocrystic origin of the oxide inclusions. These oxide inclusions are thus interpreted to be cumulus minerals crystallized together and trapped in olivine from the same parental magma. In addition to Fe–Ti oxides, some inclusions contain amphibole + biotite ± fluorapatite that might have formed by reaction of trapped hydrous liquid with the host olivine. Numerical modeling of high-Ti Emeishan basalts using the MELTS program successfully simulates early crystallization of olivine (∼Fo₈₁) and Fe–Ti spinel in the presence of a moderate amount of H₂O (∼1.5 wt%) under pressure and fO₂ conditions generally pertinent to the Panzhihua and Hongge intrusions. The modal mineralogy of the oxide inclusions is in good agreement with the bulk compositions of the ore, as inferred from whole-rock data, in a given intrusion. This is consistent with the interpretation that the stratiform oxide ores in the intrusions formed by accumulation of Fe–Ti oxide crystals that appeared on the liquidus with olivine and clinopyroxene.  相似文献   

Interaction of magma with sedimentary wall rock and magnetite ore genesis in the Panzhihua mafic intrusion,SW China   总被引：10，自引：0，他引：10  

Clément Ganino  Nicholas T. Arndt  Mei-Fu Zhou  Fabrice Gaillard  Catherine Chauvel 《Mineralium Deposita》2008,43(6):677-694

In southwestern China, several large magmatic Fe–Ti–V oxide ore deposits are hosted by gabbroic intrusions associated with the Emeishan flood basalts. The Panzhihua gabbroic intrusion, a little deformed sill that contains a large titanomagnetite deposit at its base, concordantly intrudes late-Proterozoic dolostones. Mineralogical and chemical studies of the contact aureole in the footwall dolostones demonstrate that the metamorphism was largely isochemical but released large quantities of CO₂ as the rocks were converted to marble and skarns during intrusion of the gabbroic magma. Petrological modelling of the crystallization of the intrusion, using H₂O-poor Emeishan basalt as parent magma, shows that under normal conditions, Fe–Ti oxides crystallize at a late stage, after the crystallization of abundant olivine, clinopyroxene and plagioclase. In order for titanomagnetite to separate efficiently to form the ore deposit, this mineral must have crystallized earlier and close to the liquidus. We propose that CO₂-rich fluids released during decarbonatization of sedimentary floor rocks passed up through the magma. Redox equilibria calculations show that when magma with the composition of Emeishan basalt is fluxed by a CO₂-rich gas phase, its equilibrium oxygen fugacity (fO₂) increases from the fayalite–magnetite–quartz buffer (FMQ) to FMQ + 1.5. From experimental constraints on magnetite saturation in basaltic magma under controlled fO₂, such an oxidizing event would allow magnetite to crystallize near to the liquidus, leading to the formation of the deposit.  相似文献   

Environmentally geochemical characteristics of vanadium in the topsoil in the Panzhihua mining area,Sichuan Province,China     

Yanguo Teng  Xudong Jiao  Jinsheng Wang  Wei Xu  Jie Yang 《中国地球化学学报》2009,28(1):105-111

Vanadium is a trace element, which may be biologically beneficial and possibly essential but certainly harmful to human beings and some living organisms if excessive. After over 40 years of development, the mining industry has caused serious environmental problems in the Panzhihua mining area. Vanadium is significantly accu-mulated in the soil of the Panzhihua area. Human activities have intensified the pollution and release of vanadium and caused serious damages to the ecological system there. In the past few years, the authors have made investiga-tions into and assessments on the geochemical distribution, chemical speciation, adsorption characteristics and transfer behavior of vanadium in the topsoil in the Panzhihua mining area. The results showed that: (1) the difference in the contents of vanadium in soil between premonsoon and monsoon is insignificant; (2) the adsorption isotherms of vanadium on soil in the Panzhihua mining area ate well described by the Langmuir type; (3) the transfer ability of vanadium in soil is interrelated to soil properties; and (4) the chemical speciation of vanadium shows an order of insoluble residue > oxidizable=reducible > soluble component. According to the above results, some countermea-sures to control pollution of vanadium in soil should be put forward.  相似文献   

攀枝花市土地退化过程     

张建平 《山地学报》1997,(4)

土地退化不仅是目前全球性的重大环境问题,而且也是重大的经济问题和社会问题,分析了土地退化过程的不可逆性及攀权花市的土地退化过程。  相似文献   

攀枝花层状基性侵入体氧同位素初步研究          下载免费PDF全文

牟保磊 《岩石矿物学杂志》1991,(1)

攀枝花层状辉长岩侵入体,自下而上可分为四个岩带。各种样品的δ18O值: 8个全岩样品中的6个为 6.27— 6.91‰;23个钛磁铁矿中的19个为 1.28— 2.39‰;21个斜长石中的12个为 6.18— 7.60‰。氧同位素特征表明,岩体源自上地幔。Ⅰ岩带氧同位素平衡温度较低455℃—730℃,可能是成岩后叠加地质作用影响的结果;Ⅱ岩带856—1045℃;Ⅲ岩带652—740℃;Ⅳ岩带62 1.—871℃。  相似文献   

四川攀枝花晶质石墨矿电性特征及找矿评价          下载免费PDF全文

杨剑  王桥  王绪本  宁括步  郭镜  周清  高慧 《中国地质》2022,49(1):284-297

[研究目的]石墨具有高的电子导电性,电性呈现形式为低阻(<10-5Ω·m)高极化(>40％)特征,正是由于石墨的超低阻特性,在石墨矿地球物理勘查中经常遇到"低阻屏蔽"作用,因此,优选有效的电法勘探组合在石墨矿勘查中非常重要.[研究方法]本文选择四川攀枝花中坝晶质石墨矿开展正演模拟,同时对典型矿床开展自然电位法和宽频电磁...  相似文献   

四川盐边地区志留纪牙形石生物地层及年代地层   总被引：2，自引：0，他引：2  

金淳泰  钱泳蓁  王吉礼 《地层学杂志》2005,29(3):i007-i008

首次提供了四川盐边地区从下志留统至下泥盆统连续的志留系年代地层系统的实际证据和原始材料,由上而下建立8个牙形石带,2个牙形石组合带和1个笔石带,以此为依据建立了攀枝花阶、永兴阶、箐河阶、叉河阶、透底河阶和支六阶,分别归入下泥盆统、顶志留统、上志留统、中志留统和下志留统,为我国志留系安康阶以上地层的建阶研究工作提供了实际的基础资料。四川盐边地区志留系龙马溪组为笔石相地层,其上全为碳酸盐岩相,其中牙形石发育良好,形成连续完整的牙形石带序列,这对我国和更大的范围壳相志留系年代地层系统对比提供了非常有价值的资料。  相似文献