Electrical Conduction and Polaron Mobility In Fe-Bearing Olivine   总被引：7，自引：0，他引：7  

L. M. Hirsch  T. J. Shankland  A. G. Duba 《Geophysical Journal International》1993,114(1):36-44

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四川会理河口地区辉长岩地质特征及其成矿作用          下载免费PDF全文

龚晓波  胡阳  廖阮颖子  郭道军 《地质找矿论丛》2021,36(3):283-287

扬子地台西缘的四川会理河口地区广泛出露辉长岩,呈岩墙、岩床状侵入于河口群中,且被认为与拉拉铁铜矿的成矿有密切联系。本文对侵入于河口群中的辉长岩进行地质特征研究,采用锆石LA-ICP-MS测年方法,获得了1728Ma±19Ma和1037Ma±22Ma两期锆石U-Pb年龄。结合河口群的年龄资料和区域构造演化背景,对辉长岩成岩背景、形成时代及演化等进行了研究,结合辉长岩与区域铁铜矿的时空关系探讨了区域辉长岩的成矿作用。  相似文献   

山东蒙阴金伯利岩中蛇纹石化橄榄石的微组构特征及其地质意义     

张佳伟  杨志军 《矿物岩石地球化学通报》2021,40(1):155-164

为探究山东蒙阴金伯利岩中蛇纹石化橄榄石的微组构特征、蚀变环境、元素迁移规律及其对金伯利岩表生演化的指示意义,对该区金伯利岩中部分蛇纹石化的橄榄石和完全蚀变的橄榄石进行了XRD、EPMA和LA-ICP-MS分析测试。结果表明,蛇纹石中少部分Mg被Fe、Al、Ca、Ni、Mn取代,其中Fe含量仅次于Mg;从蚀变橄榄石的中心到边缘,Li与Zn、Ba与Sc、Co与Y含量分别呈3组变化趋势;部分蚀变的橄榄石为负Eu异常、低氧逸度,推测其形成于封闭的还原环境;完全蚀变的橄榄石无Eu异常,氧逸度相对较高,推测其形成于更开放的偏氧化环境;未完全蚀变的橄榄石大部分微量元素含量都高于完全蚀变橄榄石;稀土元素在蛇纹石化过程中可能存在迁移活动。  相似文献   

粤北石人嶂钨矿区角闪辉长岩地球化学、年代学特征及其地质意义     

秦锦华  王登红  黄凡  赵如意  刘士岩  洪文亮  魏东 《矿床地质》2023,42(5):978-1002

石人嶂钨矿区发育的角闪辉长岩与钨矿密切共生,研究该矿区对认识粤北地区区域地质演化、深部岩浆信息以及区域基性岩与成钨作用关系研究意义重大,但到目前为止,尚未开展相关系统的研究。文章报道了角闪辉长岩的锆石和磷灰石U-Pb年代学、地球化学资料。磷灰石U-Pb年龄指示角闪辉长岩的结晶年龄为（171±14） Ma,形成于燕山早期晚阶段古太平洋板块俯冲背景下的岩石圈伸展的构造环境,其中,锆石为捕获锆石,具有3组年龄,分别记录了区域古元古代陆核增生,新元古代古华南板块的聚合和裂解,早中生代华南板块与华北板块,印支地块聚合的后造山伸展等多起构造事件。角闪辉长岩具有低Si、K、Mn,高Ca、Fe、Mg、Na、Ti的特征,富集Rb、Ta、Zr、Ti等,亏损Ba、Nb、Sr、Hf、Be、Cs、U、Th等元素,表明其源区具有E-MORB型富集地幔的属性。角闪辉长岩的形成主要受控于软流圈地幔的部分熔融。同时,由于角闪辉长岩的高氧逸度的特征及其较石人嶂钨矿成矿更早,角闪辉长岩的存在可能主要是为后期的钨矿化的叠加提供部分Ca、Fe等元素,并为富矿流体的运移提供通道。  相似文献   

New Olivine Reference Material for In Situ Microanalysis     

Valentina G. Batanova  Jay M. Thompson  Leonid V. Danyushevsky  Maxim V. Portnyagin  Dieter Garbe‐Schnberg  Erik Hauri  Jun‐Ichi Kimura  Qing Chang  Ryoko Senda  Karsten Goemann  Catherine Chauvel  Sylvain Campillo  Dmitri A. Ionov  Alexander V. Sobolev 《Geostandards and Geoanalytical Research》2019,43(3):453-473

A new olivine reference material – MongOL Sh11‐2 – for in situ analysis has been prepared from the central portion of a large (20 × 20 × 10 cm) mantle peridotite xenolith from a ~ 0.5 My old basaltic breccia at Shavaryn‐Tsaram, Tariat region, central Mongolia. The xenolith is a fertile mantle lherzolite with minimal signs of alteration. Approximately 10 g of 0.5–2 mm gem quality olivine fragments were separated under binocular microscope and analysed by EPMA, LA‐ICP‐MS, SIMS and bulk analytical methods (ID‐ICP‐MS for Mg and Fe, XRF, ICP‐MS) for major, minor and trace elements at six institutions world‐wide. The results show that the olivine fragments are sufficiently homogeneous with respect to major (Mg, Fe, Si), minor and trace elements. Significant inhomogeneity was revealed only for phosphorus (homogeneity index of 12.4), whereas Li, Na, Al, Sc, Ti and Cr show minor inhomogeneity (homogeneity index of 1–2). The presence of some mineral and fluid‐melt micro‐inclusions may be responsible for the inconsistency in mass fractions obtained by in situ and bulk analytical methods for Al, Cu, Sr, Zr, Ga, Dy and Ho. Here we report reference and information values for twenty‐seven major, minor and trace elements.  相似文献   

内蒙古北山小黑山辉长岩LA-ICP-MS锆石U-Pb年龄及地球化学特征          下载免费PDF全文

刘强  赵志雄  贾元琴  许海  王新亮  高鉴 《中国地质调查》2019,6(1):41-47

内蒙古北山地区泥盆纪岩浆作用的研究对于探讨晚古生代早期的构造演化具有十分重要的意义。小黑山辉长岩的LA-ICP-MS锆石U-Pb定年结果显示,其就位年龄为(404.9±1.6) Ma,为早泥盆世。岩石学和地球化学分析结果表明: 岩石SiO₂含量低,富Al、Ca,低K、P, Mg^#值大,属于钙碱性岩石系列; 岩石稀土元素总量低,富集轻稀土,轻、重稀土元素之间分馏相对明显,具有正Eu异常(δEu=1.70~1.71); 岩体富集大离子亲石元素Ba、Sr、K等和强不相容元素U,亏损高场强元素Nb、Ta、Ti等。综合区域地质、地球化学特征,认为该岩体形成的构造环境为火山弧,岩浆上升过程中遭受到地壳物质的混染,进而认为本区泥盆纪仍处于造山作用过程中。  相似文献   

Rocky relationships: the petroglyphs of the Murujuga (Burrup Peninsula and Dampier Archipelago) in Western Australia     

E. R. Ramanaidou  L. C. Fonteneau 《Australian Journal of Earth Sciences》2019,66(5):671-698

The petroglyphs of the Murujuga (Burrup Peninsula and Dampier Archipelago) in Western Australia are of exceptional cultural value for the nation. It is Australia’s largest and most significant collection of aboriginal rock art essentially as petroglyphs, with the number estimated at more than one million engravings. The Murujuga is a textbook example of ancient and modern times colliding as it also hosts potentially polluting, major industrial complexes such as iron ore and salt ports; liquefied natural gas, liquid ammonia and ammonium nitrate plants; railway lines, pipelines and rock quarries. The work presented in this paper is underpinned by an annual monitoring study of 10 selected sites including two control sites located on Dolphin and Gidley islands and eight test sites located closer to the industrial areas. The main rock types of the Murujuga, gabbro and granophyre, have been affected by weathering consisting of a cm-thick leached zone capped by a skin of orange and red iron and manganese oxides. The petroglyphs were engraved by removing the few top millimetres of the iron oxide-rich layer and the contrast with the paler leached zone clearly showing the carved motifs. Phosphorus is abnormally enriched in the leached zone and the surface coating, with manganese exclusively on the surface coating, demonstrating the impact of bird droppings and ‘desert varnish’ on the rocks. The colour difference and the hematite–goethite ratio, measured with a field portable reflectance spectrometer, between the background and engraving provides a tool to estimate the relative age of the petroglyphs and the selection of the backgrounds. As the fine-grained granophyres were preferentially chosen from the coarser-grained gabbros to host the petroglyphs, the goethitic (or yellower) backgrounds were prepared as canvas before being engraved. Many petroglyphs register the food items of the area, which changed as the last ice age ended and sea levels rose. We hypothesise that based on their locations and colour difference the constraint for the oldest age of the petroglyphs exceeds 17 000?years BP.  相似文献   

内蒙古中部查干诺尔辉长岩体地球化学特征及其地质意义     

张祥信  高永丰  雷世和 《地球化学》2019,(3):230-248

查干诺尔辉长岩体由角闪辉长岩和辉长闪长岩组成,呈岩株状侵入于晚石炭世花岗闪长岩和上石炭统宝力高庙组中。角闪辉长岩LA-ICP-MS锆石U-Pb年龄为302Ma,表明该岩体的形成时代为晚石炭世。查干诺尔辉长岩具有高铝钙、低钛和贫碱的特征,属于钙碱性系列岩石。相对富集大离子亲石元素(LILE),亏损高场强元素(HFSE),具明显的Nb、Ta、Ti、Zr、Hf负异常和Pb正异常,与典型的弧岩浆类似。岩石稀土总量较低且变化范围大(ΣREE=63.4~135μg/g),轻、重稀土元素分异程度中等,无明显的Eu异常;稀土元素分布模式表现为轻稀土富集、重稀土平坦且向右缓倾型式。Sr-Nd同位素组成为低(87Sr/86Sr)i(0.70407~0.70428)、正εNd(t)(1.62~3.47),显示了亏损地幔源区的同位素特征;有较高的Pb同位素比值,(206Pb/204Pb)i为17.816~18.040,(207Pb/204Pb)i为15.472~15.484,(208Pb/204Pb)i为37.242~37.534。上述地球化学特征表明查干诺尔辉长岩形成于晚石炭世大陆弧环境,是交代岩石圈地幔含角闪石二辉橄榄岩在低压条件下低程度部分熔融的产物,交代组分来自古亚洲洋闭合期间俯冲板片释放的流体。查干诺尔辉长岩的厘定可能表明内蒙古中部贺根山洋晚石炭世往北俯冲的时间持续至302Ma,并在早二叠世发生闭合。  相似文献   

东昆仑西段巴什康阔勒辉长岩地球化学特征及其构造意义     

郑勇  杨有生  陈邦学  朱彦菲 《现代地质》2016,30(5):1004-1013

通过主微量元素特征研究,MgO、FeO含量分别介于 578%~123%和516%~104%,Al2O3含量介于142%~2156%,整体含量较高。TiO2含量相对较高,介于018%~132%,平均为077%,与岛弧拉斑玄武岩的084%较为接近,K2O含量偏低,介于005%~053%,平均为02%,与洋中脊拉斑玄武岩02%一致;轻稀土元素富集,重稀土元素亏损;富集大离子亲石元素(K除外),高场强元素Ti、P等轻微富集,而Nb、Zr亏损,结合构造环境判别认为形成环境为弧后盆地。利用锆石U Pb测年,获得两组年龄,其中上交点206Pb/238U表面年龄加权平均值(501±1) Ma(MSWD=025),为寒武世晚期,代表原岩结晶年龄;下交点206Pb/238U表面年龄加权平均值(451±2) Ma(MSWD=0084),为晚奥陶世早期,代表变质年龄。结合主量和微量元素特征、构造环境以及同位素年龄,认为洋壳俯冲始于晚寒武世之前,且在晚奥陶世已开始发生碰撞。  相似文献   

内蒙古东部碧流台地区辉长岩锆石U-Pb测年、地球化学特征及其成因     

郜晓勇  李永飞  孙守亮 《地质与资源》2015,24(3):184-192

对内蒙古东部碧流台辉长岩进行了岩石学、地球化学与锆石LA-ICP-MS U-Pb测年分析研究.测年结果显示辉长岩形成时代为早三叠世早期（249±2.9 Ma）.岩石地球化学特征显示该辉长岩为一套钙碱性系列岩石：SiO₂含量为46.43%~50.77%,Al₂O₃ 11.27%~16.32%,TiO₂ 0.20%~0.37%;富钠（Na₂>K₂O,K₂O/Na₂=0.18~0.56）;高Mg^#,含量为75.08~78.93;轻重稀土分异较弱,（La/Yb）_N=2.32~3.99,（Ce/Yb）_N=2.45~3.45;岩石富集大离子亲石元素Rb、Ba、Th、U、K,亏损高场强元素Nb、Ta、P、Ti、Zr,具有俯冲带构造背景特征.结合区域资料,碧流台辉长岩母岩浆应该是古亚洲洋闭合后,西伯利亚古板块和中朝古板块碰撞造山带受流体交代过的岩石圈地幔部分熔融作用的产物.  相似文献