长白山区图们江流域新生代火山岩的岩石化学研究

图们江流域新生代火山岩以溢流式喷发为特征，其主要岩石类型以拉斑玄武岩为主，含少量玄武质粗安岩、碱性玄武岩、玄武质安山岩和粗面玄武岩。根据图们江流域火山岩的Mg#（Mg#=100Mg^2＋／（Mg^2＋＋Fe^2＋））值多数≤60，Ni含量〈100μg／g和主、微量元素地球化学特征综合表明，形成火山岩的岩浆不是原始岩浆，它们是原始岩浆在上地幔经历了橄榄石、辉石分离结晶作用后形成的以拉斑玄武岩为主，包括碱性玄武岩和粗面玄武岩等演化岩浆，结晶分异作用是岩浆演化过程的主要控制因素。拉斑玄武质岩浆在上升过程中发生了不同程度的壳源物质同化混染作用，发生在上地壳遭受较大程度混染的岩浆K2O含量明显偏高（〉2．6％），形成玄武质粗安岩。     

辽河盆地始新世中基性火山岩成因:地球化学和Sr-Nd同位素证据

辽河盆地位于郯庐断裂带北段,地处华北陆块东部,是我国东部大型新生代含油气裂谷盆地。近年来,随着勘探和研究程度的不断深入,尤其对火山岩储层勘探获得重大突破后,盆地内火山岩的研究得到了更多的重视和关注。盆地断陷期发育的厚层始新统沙河街组三段火山岩是本区最为重要的油气储集层。有关这套火山岩的研究,已有的成果主要集中在火山岩油气藏勘探开发和年龄测定方面,而涉及火山岩成因和形成动力学机制的研究较为欠缺。因此,本文利用井下样品对辽河盆地始新世火山岩进行了相关研究。辽河盆地始新统沙河街组三段火山岩主要由基性端元的玄武质岩石和中性端元的粗面质岩石构成,上部和下部为玄武质岩石,中部则主要发育粗面质岩石及少量玄武质岩石夹层。玄武质岩石的w(Si O2)为47.75%~53.71%,w(K2O)较低(0.64%~1.82%),全碱质量分数低—中等(3.42%~6.80%),较高的w(Mg O)(3.78%~9.73%)和Mg#(44~65),Eu呈正异常(1.03~1.26);总体富集高场强元素,相对亏损大离子亲石元素,具明显的Ba、Sr和Zr正异常。粗面质岩石具有较高的w(Si O2)(55.35%~60.70%)、w(K2O)(3.95%~9.46%)和全碱(8.41%~12.70%)质量分数,相对低的w(Mg O)(0.44%~1.69%)和Mg#(17~45),其中多数岩石具有负Eu异常(δEu=0.37~0.77),部分没有明显Eu异常(0.81~0.96);富集大离子亲石元素、亏损高场强元素,Sr、Ti和Ba强烈亏损。玄武质岩石的初始87Sr/86Sr值为0.703 3~0.704 2,εNd(t)=3.56~5.86,显示岩浆源区具有亏损地幔的特征;粗面质岩石的初始87Sr/86Sr值为0.703 5~0.704 5,εNd(t)=3.25~4.46,与玄武质岩石几乎完全一致,暗示玄武质岩石和粗面质岩石具有相同的岩浆源区。根据本文对辽河地区始新世火山岩的综合研究,结合华北东部古近纪时期的构造环境及岩石圈演化特征,我们认为:本区玄武质岩石来源于板内软流圈地幔的上涌,同时有来自俯冲的大洋岩石圈成分的加入,是软流圈地幔上涌和岩石圈地幔减薄过程中,软流圈地幔较低程度部分熔融的产物,并经历了橄榄石和辉石的分离结晶作用。玄武质岩浆上升到较浅部位后进一步发生橄榄石、辉石、斜长石和磁铁矿等的分离结晶作用而形成粗面质岩石,地壳物质的混染作用不显著。     

华北晚中生代和新生代玄武岩中单斜辉石巨晶来源及其对寄主岩岩浆过程的制约:以莒南和鹤壁为例

本文对华北克拉通晚中生代和新生代碱性玄武质岩石中的单斜辉石巨晶进行了主、微量元素和Sr-Nd同位素的综合研究,发现晚中生代和新生代单斜辉石巨晶存在明显的主、微量元素和同位素组成上的差异。新生代单斜辉石巨晶有Al-普通辉石和次透辉石两类;而中生代单斜辉石巨晶只有Al-普通辉石。新生代单斜辉石SiO_2含量高、REE配分型式为上凸型、LILE和放射性元素含量高,并具有比寄主碱性玄武岩更亏损的Sr和Nd同位素组成;而中生代单斜辉石SiO_2含量低、REE配分型式为LREE富集型、LILE和部分HFSE以及放射性元素含量低,并具有比寄主碱性玄武岩稍富集的Sr和Nd同位素组成;巨晶的结构、矿物成分和地球化学特征,以及Mg-Fe在熔体与单斜辉石间的分配状况皆说明,新生代碱性玄武岩中单斜辉石巨晶是碱性玄武岩浆在高压下结晶的,因此二者是同源的;而中生代单斜辉石巨晶是被寄主岩浆偶然捕获的捕虏晶,是不同源的。华北新生代单斜辉石巨晶存在于碱性玄武岩和拉斑玄武岩中,它们具有比寄主碱性玄武岩更亏损的Sr和Nd同位素组成,说明即使是碱性玄武岩也不能完全代表软流圈来源的原始岩浆,其在上升过程中或多或少存在同位素组成富集的物质的混入。同时,拉斑玄武岩不是碱性玄武质岩浆直接结晶分异的产物,亦不是完全由部分熔融程度的不同造成的。拉斑玄武岩中存在岩石圈地幔物质的贡献或是岩浆房内碱性玄武质岩浆受地壳混染作用的结果。     

塔里木盆地南北缘新生代火山岩成因及其地质意义

塔里木盆地南北缘几个地方的新生代火山岩类具有贫硅富碱、特别是富钾的特点 ,均属于碱性火成岩系列。大部分样品SiO2 质量分数低于 5 3% ,全碱质量分数大于 3%。按照全碱 SiO2 的关系 ,它们可以划分为 3种类型 :钾质碧玄岩钾质粗面玄武岩钾质碱性橄榄玄武岩类、钾质橄榄安粗岩粗面岩类和钾质粗面玄武岩橄榄玄武粗安岩安粗岩类。岩石普遍含有橄榄石、单斜辉石、斜长石与黑云母等矿物斑晶 ,部分火山岩中见有辉石、金云母、角闪石高压巨晶 ,岩石地球化学特征与幔源捕虏体和高压巨晶的产出表明它们具有原生岩浆的性质。岩石地球化学参数的变异趋势暗示岩浆起源于深部流体强烈活动的地幔环境 ,而不是受控于分离结晶作用。岩浆活动受控于印度 -亚洲大陆碰撞构造体制派生的大型走滑体制 ,与大陆裂谷、地幔柱和陆内俯冲作用无关。     

长白山望天鹅火山双峰式火山岩的成因演化

望天鹅火山活动从早到晚分为三期：①长白期以粗面玄武岩为主,少量碱性玄武岩和玄武质粗安岩;②望天鹅期又分早晚两个亚期,早期玄武质粗安岩和粗面岩,晚期碱性流纹岩;③红头山期碱性流纹岩。望天鹅火山岩的岩石学、ＲＥＥ、不相容元素和Ｎｄ、Ｓｒ、Ｐｂ同位素（１４３Ｎｄ／１４４Ｎｄ、８７Ｓｒ／８６Ｓｒ、２０６Ｐｂ／２０４Ｐｂ分别变化于０．５１２５６７～０．５１２６４２、０．７０５１９８～０．７１６７４２和１７．４３４～１７．９３４）,揭示了岩浆源区明显受洋壳的俯冲和壳幔混合混染,三期火山岩具有共同的岩浆源区和紧密的成因演化关系,分离结晶作用控制了岩浆的演化过程。原始碱性系列玄武质岩浆经橄榄石、辉石的结晶分异,向粗面玄武岩演化;粗面玄武岩经斜长石强烈的结晶分离作用,还有辉石、钛铁氧化物和磷灰石的分离结晶作用形成具显著Ｅｕ、Ｓｒ、Ｂａ、Ｔｉ、Ｐ负异常的碱性流纹岩,导致本区火山岩缺失中性（ＳｉＯ２＝５７％～６３％）的安山岩和粗安岩,呈现双峰式火山岩组合的特点。     

鲁西邹平盆地中生代火山岩的演化:对地幔源区的约束

邹平盆地中生代火山岩可分为三个亚组：中、下亚组具有相似的岩石组合,岩性主要为玄武岩-粗面玄武岩-玄武质粗面安山岩-粗面安山岩;上亚组岩性主要为粗面安山岩。火山岩由早期基性向晚期中偏碱性方向演化,与正常岩浆房酸度增高的岩浆分异趋势相同。具有Rb、Ba、Sr等大离子亲石元素（LILE）和轻稀土元素（LREE）富集,Nb、Ta、Ti等高场强元素（HFSE）相对亏损,类似于岛弧火山岩的地球化学特征。Nb／La、Hf／Sm比值随MgO的降低而升高或基本不变,说明高场强元素亏损是岩浆的原始特征。各亚组火山岩相似的稀土配分模式和微量元素蛛网图,表明它们具有共同的岩浆源区和密切的成因联系,分离结晶起了关键性作用。La／Nb、La／Ta、Ba／Nb比值较高,说明成岩物质可能主要来自岩石圈地幔。拆沉的大陆中、下地壳部分熔融形成的熔体与古生代岩石圈地幔（亏损的地幔橄榄岩）的相互作用是岩石圈地幔富集的重要方式,随之该富集地幔在陆内岩石圈伸展和区域热异常的双重作用下发生减压部分熔融而形成具有岛弧特征的邹平盆地火山岩。     

云南金宝山镁铁-超镁铁岩的地球化学特征及成因

金宝山超镁铁侵入岩赋存有超大型硫化物铂族元素矿床。单辉橄榄岩是岩区员主要的含矿岩石类型。根据单辉橄榄岩的矿物学、岩石学、岩石化学及微量元素地球化学特征，探讨岩浆的结晶分异演化过程，提出岩体的形成与岩浆结品分异有关，母岩浆成分为拉斑质玄武质岩浆。岩体高镁、高稀土总量，以及橄榄石与辉石的结构特征显示岩体是橄揽石、铬尖晶石等矿物与残留岩浆混合形成。     

《变质作用与大陆动力学学术讨论会》在北京召开

冲绳海槽火山岩目前发现有玄武岩、玄武安山岩、安山岩、粗面安山岩、粗面英安岩、英安岩和流纹岩。研究表明，冲绳海槽火山岩均属亚碱性系列，基性岩具有拉斑玄武岩系列和钙碱性系列的过渡性，中、酸性岩多属钙碱性系列；岩石形成于上新世以来，大部分都是富集型地幔玄武质岩浆在分离结晶不同阶段的产物。岩石在分离结晶演化趋势上的一致性和在岩石化学指数变异关系上的多样性是原来快速上升未发生混染的岩浆在断裂构造隔离下分枝独立演化的结果。     

冲绳海槽火山岩岩石特征及其地质意义

冲绳海槽火山岩目前发现有玄武岩、玄武安山岩、安山岩、粗面安山岩、粗面英安岩、英安岩和流纹岩。研究表明，冲绳海槽火山岩均属亚碱性系列，基性岩具有拉斑玄武岩系列和钙碱性系列的过渡性，中、酸性岩多属钙碱性系列；央石形成于上新世以来，大部分都是富集型地幔玄武质岩浆在分离结晶不同阶段的产物。岩石在分离结晶演化趋势上的一致性和岩石化学指数变异关系上的多样性是原来快速上升未发生混染的岩浆在断裂构造隔离下分枝独立     

贝加尔裂谷带通京盆地呼兰霍博克火山的玄武岩岩石学和地球化学特征

位于贝加尔裂谷带西南端通京盆地的呼兰霍博克火山为玄武岩质碎屑锥,玄武岩由高拉长石、贵橄榄石、普通辉石和火山玻璃组成,其矿物组成及SiO2-（Na2O＋K2O）图和Hf-Th-Ta图指示为碱性玄武岩.CIPW标准矿物特征、岩石化学成分和单斜辉石化学成分特征表明岩石属碱性系列,钠质型.稀土元素和微量元素的地球化学特征表明岩石为裂谷初期玄武岩.初步推断原始岩浆来源于上地幔,斑晶可能于16.5 km深处的次生壳层岩浆房结晶.     

峨眉山大火成岩省晚期酸性火山岩的岩石地球化学特征

峨眉山大火成岩省出露有少量酸性火山岩,它们与基性火山岩共生,表现出双峰式的特征,为研究峨眉山地幔柱晚期岩浆活动提供了重要的窗口。本文通过对双峰式火山岩主、微量元素和斑晶电子探针分析研究表明,基性火山岩属于碱性玄武岩,酸性火山岩主要由粗面岩组成;相对玄武岩,粗面岩中MgO、Fe2O3、P2O5、TiO2、CaO含量明显降低;粗面岩与玄武岩具有相互平行的REE配分模式,但粗面岩出现明显的Eu负异常,以及Sr、Ti等元素的强烈亏损;粗面岩与玄武岩具有同源的特征,通过稀土元素模拟计算表明粗面岩可以由玄武质岩浆经过80%分离结晶作用(辉石、斜长石和Fe-Ti氧化物)而形成。在峨眉山大火成岩省晚期出现双峰式火山岩,可能与地幔柱活动晚期岩浆供给少,在地壳岩浆房中停留时间长,岩浆发生强烈分离结晶作用有关。     

The composition and sources of magmas of Changbaishan Tianchi volcano (China-North Korea)

The Changbaishan Tianchi volcano is the greatest stratovolcano within the bounds of the Late Cenozoic intraplate volcanic province of East Asia. Changbaishan Tianchi volcanic cone consists mostly of trachytes and pantellerites. It was found that the lavas composing the shield platform of Changbaishan Tianchi volcano are weakly differentiated basic rocks whose geochemical characteristics are generally similar. All the alkaline salic rocks composing the cone of the volcano are characterized by conformable normalized trace element patterns. The concentrations of rare-earth elements in these rocks are high and amount up to 1000 ppm. The character of the distribution of trace elements in the basic rocks of Changbaishan Tianchi volcano is close to that in the OIB-type basalts. Within the series from basalts to pantellerites, the rocks are enriched in REE and zirconium, but depleted in barium, strontium, and europium. According to the obtained geochemical data, it was shown that the rock series of Changbaishan Tianchi volcano, varying from basalts to trachytes and pantellerites comprises compositions geochemically interrelated by the processes of crystal fractionation. The parental magma for the rocks of the volcano was derived from plume sources of the same type as those of OIB and sources of the Late Cenozoic intraplate province of East Asia.     

广东三水盆地火山岩: 地球化学特征及成因--兼论火山岩性质的时空演化和南海形成的深部过程

位于中国东南部的三水盆地、珠江口盆地、雷琼半岛和北部湾地区广泛分布新生代火山岩。火山岩的形成时间具有从内陆向沿海变新的特点,早第三纪三水和珠江口盆地火山岩具有由玄武岩与粗面岩-流纹岩构成的双峰式特点。其中玄武岩和粗面岩的微量元素和稀土元素的配分形式相似,富集大离子亲石元素并且有相似的εNd(T)同位素组成(2.34～6.4),说明它们来自相同的地幔源区,为同源岩浆演化的产物。玄武岩和粗面岩经历了不同的结晶分异过程,其中玄武岩在较深部岩浆房中经历橄榄石和单斜辉石为主的分离结晶作用,而粗面岩则是在浅部岩浆房中由玄武岩浆分异形成的过渡性岩浆再经过强烈的钾长石和斜长石、以及磷灰石的结晶分异形成的。晚第三纪珠江口盆地和北部湾火山岩、雷琼半岛第四纪火山岩则由碱性和拉斑玄武岩构成。这些火山岩的形成时间和地球化学和同位素特征表明它们经历了连续的软流圈地幔上涌和部分熔融过程,受控于自晚中生代以来的地幔柱构造。南海的形成是地幔柱活动引起的地幔上涌和大陆裂解作用的结果。     

Major,trace element and Sr isotopic composition of lavas from Vico volcano (Central Italy) and their evolution in an open system

Major, trace element and Sr isotopic compositions have been determined on 21 lava samples from Vico volcano, Roman Province, Central Italy. The rocks investigated range from leucite tephritic phonolites to leucite phonolites and trachytes. Trace element compositions are characterized by high enrichments of incompatible elements which display strong variations in rocks with a similar degree of evolution. Well-defined linear trends are observed between pairs of incompatible trace elements such as Th-Ta, Th-La, Th-Hf. A decrease of Large Ion Lithophile (LIL) elements abundance contemporaneously with the formation of a large central caldera is one of the most prominent characteristics of trace element distribution. Sr isotope ratios range from 0.71147 to 0.71037 in the pre-caldera lavas and decreases to values of 0.70974–0.70910 in the lavas erupted after the caldera collapse. Theoretical modelling of geochemical and Sr isotopic variations indicates that, while fractional crystallization was an important evolutionary process, AFC and mixing also played key roles during the evolution of Vico volcano. AFC appears to have dominated during the early stages of the volcanic history when evolved trachytes with the highest Sr isotope ratios were erupted. Mixing processes are particularly evident in volcanites emplaced during the late stages of Vico evolution. According to the model proposed, the evolution of potassic magmas emplaced in a shallow-level reservoir was dominated by crystal fractionation plus wall rock assimilation and mixing with ascending fresh mafic magma. This process generated a range of geochemical and isotopic compositions in the mafic magmas which evolved by both AFC and simple crystal liquid fractionation, producing evolved trachytes and phonolites with variable trace element and Sr isotopic compositions.     

Geochemistry of subalkaline and alkaline extrusives from the Kermanshah ophiolite,Zagros Suture Zone,Western Iran: implications for Tethyan plate tectonics

The Kermanshah ophiolite is a highly dismembered ophiolite complex that is located in western Iran and belongs to the Zagros orogenic system. The igneous rocks of this complex consist of both mantle and crustal suites and include peridotites (dunite and harzburgite), cumulate gabbros, diorites, and a volcanic sequence that exhibits a wide range in composition from subalkaline basalts to alkaline basalts to trachytes. The associated sedimentary rocks include a variety of Upper Triassic to Lower Cretaceous deep- and shallow-water sedimentary rocks (e.g., dolomite, limestone, and pelagic sediments, including umber). Also present are extensive units of radiolarian chert. The geochemical data clearly identifies some of the volcanic rocks to have formed from two distinct types of basaltic melts: (i) those of the subalkaline suite, which formed from an initial melt with a light rare earth elements (LREE) enriched signature and incompatible trace element patterns that suggest an island arc affinity; and (ii) those of the alkaline suite with LREE-enriched signature and incompatible trace element patterns that are virtually identical to typical oceanic island basalt (OIB) pattern. The data also suggests that the trachytes were derived from the alkaline source, with fractionation controlled by extensive removal of plagioclase and to a lesser extent clinopyroxene. The presence of compositionally diverse volcanics together with the occurrence of a variety of Triassic–Cretaceous sedimentary rocks and radiolarian chert indicate that the studied volcanic rocks from the Kermanshah ophiolite represent off-axis volcanic units that were formed in intraplate oceanic island and island arc environments in an oceanic basin. They were located on the eastern and northern flanks of one of the spreading centers of a ridge-transform fault system that connected Troodos to Oman prior to its subduction under the Eurasian plate.     

Low-Ti melts from the southeastern Siberian Traps Large Igneous Province: Evidence for a water-rich mantle source?

Siberian Traps Large Igneous Province (STLIP) is one of the most voluminous volcanic provinces on Earth. The dominant erupted rocks are low-Ti basalts, which make up 80% by volume of the classical Noril’sk lava sequence. In the west Siberian basin and Maymecha-Kotuy area, the low-Ti basalts make up about 99% and 50% by volume, respectively. Dolerite sills in the Angara-Taseevskaya Syncline at the southeastern STLIP exhibit trace element patterns and Sr isotope ratios typical of the low-Ti basalts of the Noril’sk sequence. The most Mg-rich (MgO 9.5–11 wt%) and hence least differentiated dolerites are characterized by trace element patterns with Ta-Nb depletion, low Ce/Pb and high Sr/Pr. These trace element features are similar to water-saturated, mantle wedge-derived island arc basalts. These imply an important role of subduction fluid-derived trace elements in the source of melting beneath the Angara-Taseevskaya Syncline and other regions of the STLIP. Less magnesium rocks (MgO 3.8–6.1 wt%) with less prominent Ta-Nb depletion, higher Ce/Pb and lower Sr/Pr could be produced via olivine-plagioclase fractionation of primary high-magnesium melts.     

The petrology and geochemistry of the Azores Islands

Forty lavas from the Azores Islands have been analyzed for ⁸⁷Sr/⁸⁶Sr ratios, major elements, first transition series metals, and LIL elements. The samples belong to the alkali basalt magma series but range from transitional hy-normative basalts from Terceira to basanitoids from Santa Maria. Differentiated lavas include both typical trachytes and comenditic trachytes and comendites. Major and trace element concentrations define smooth trends on variation diagrams, and these trends can be related to phases crystallizing in the rocks. Systematic interisland differences are also apparent in these variation diagrams. LIL element concentrations in island basalts are roughly twice as high as those in tholeiites from the adjacent Mid-Atlantic Ridge which transects the Azores Plateau. ⁸⁷Sr/⁸⁶Sr ratios in lavas from 6 of the 9 islands range from 0.70332 to 0.70354, a range similar to that found in tholeiites from the Mid-Atlantic Ridge transect of the Azores Plateau. This suggests that lavas from these islands and this portion of the Mid-Atlantic Ridge may be derived from a similar source. However, lavas from the islands of Faial and Pico have ⁸⁷Sr/⁸⁶Sr ratios up to 0.70394 and ratios in Sao Miguel lavas range up to 0.70525, suggesting basalts from these islands are derived from a chemically distinct source. Differences in the average LIL element concentrations of the least fractionated ridge tholeiites from the Azores Plateau and alkali basalts from the islands result from differences in extent of partial melting and residual mineralogy. The alkali basalts are derived by roughly half as much melting as are the tholeiites. Trace element concentrations in Azores peralkaline lavas preclude their derivation by partial melting of peridotitic mantle or basaltic crust; rather the data suggest they are produced by fractional crystallization of a basaltic parent.     

The distribution of trace elements during strong fractionation of basic magma—a further study of the Skaergaard intrusion,East Greenland

A number of trace elements have been determined spectrographically in the rocks and minerals of the Skaergaard intrusion, East Greenland. The original basic magma from which the varied rocks of the complex were developed is shown to have had a normal trace element composition. The sorting out of the trace elements into the various mineral series produced by strong fractional crystallization of the original basic magma is traced in detail by means of analyses of the separated minerals. Certain of the trace elements (Cr, Ni) are shown to be strongly concentrated in the early rocks so that later fractions have little or none of them; other elements (P, V, Cu, Sc, Mn, S) reach maximum values in the middle, or late middle stages represented by certain olivine-free gabbros and ferrogabbros; other elements (Li, Zr, Y, La, Ba, Rb) tend to remain in the residual liquid during fractionation and are thus abundant in the latest granite fraction. Still other trace elements (Co, Sr, Ga, Mo) show only small changes in amount throughout the series. Of these Co is a little more abundant in the early and middle stages, Sr in the middle stages, Ga in the later stages and Mo in the early and later but not in the middle stages. The distribution of the trace elements in the rocks is considered in relation to the varying composition of the minerals produced by the fractional crystallization processes and an attempt is made to discuss the mineral compositions in terms of crystal chemical concepts.The Skaergaard sequence of differentiation from gabbros, through ferrogabbros, to granite is considered to be a common trend of fractionation of basic magma at high levels in the crust, and the observed changes in trace element composition are therefore regarded as having wide geochemical significance. The trace element composition of the intermediate Skaergaard differentiates is significantly different from that of diorites reported by other workers and suggests that diorites have had some other origin than by fractionation of basic magma. On the other hand the trace element composition of many granites resembles that of the granite fraction produced in the Skaergaard intrusion.     

西天山托云盆地及周边中新生代岩浆活动的岩石学、地球化学与年代学研究

天山西南部白垩纪-老第三纪发育的托云盆地及其周边出露的岩浆岩是一套完整的碱性岩浆岩系列，包含了苦橄质玄武岩、玄武岩、碧玄岩、碱玄岩（橄榄玄武岩、黑云母辉长二长岩、辉长辉绿岩、辉石橄榄岩）和响岩等多种岩石类型。野外工作显示有火山喷出岩和侵入岩两种不同的产状。年代学结果指示岩浆岩形成于120-50Ma间，为晚白垩世-老第三纪盆地形成演化阶段岩浆活动的产物。分离结晶作用是岩浆演化和岩浆系列形成最主要的因素，托云岩浆岩大致经历了结晶分异过程的两个阶段：早期苦橄质岩浆中橄榄石、尖晶石的结晶分离，表现为MgO和微量元素Cr含量随SiO2含量增加大幅度的降低；晚期主要是单斜辉石、斜长石和钛铁矿等矿物的结晶分异，以CaO、FeO、TiO2等随SiO2含量增加大幅度的降低为特点。苦橄质岩石的出现指示了地幔较高温熔融事件的存在，进而为托云盆地地幔柱的存在提供了有力的证据。无论如何，碱性岩浆的活动表明托云盆地形成的大地构造背景是大陆主动裂谷环境，对应的深部背景为区域性的地幔柱构造。首次发现的响岩是结晶分异作用的最终产物。响岩较极端地指示了岩浆结晶分离过程对岩浆演化的巨大影响。托云岩浆岩的同位素特征指示其源区是一个接近于PREMA地幔，但微量元素特征显示其受地壳流体交代改造的特点。岩浆岩的Nd同位素TDM集中在250～600Ma之间，反映了一个古生代时期形成的新生岩石圈地幔，与新疆北部地区的晚古生代新生岩石圈地幔的事实相符。     

峨眉山玄武岩微量元素地球化学的初步研究

峨眉山玄武岩的微量元素丰度显示区域性差异,西岩区(盐源—丽江拗陷)玄武岩总体上比中、东岩区(康滇隆起和滇黔拗陷)玄武岩富相容元素而贫不相容元素,主要是因为它们的母岩浆经历的结晶分离的程度不同。比较演化的石英拉斑玄武岩、安山玄武岩往往富放射成因锶,反映其成因还涉及一定程度的地壳混染。相对主体拉斑玄武岩,东川碱性火山岩贫REE特别是LREE,推测源区发生过先期熔融事件。主要元素和REE的模拟计算表明,二滩粗面岩可以由玄武质母岩浆经分离结晶衍生,最可能的主要分离相是该区似层状辉长岩的矿物组合。