排序方式: 共有8条查询结果,搜索用时 31 毫秒
1
1.
2.
金矿赋存于二长斑岩与玄武岩接触带,局部赋存于二长斑岩与大理岩、玄武岩与大理岩的接触带。脉状、似层状、透镜状产出。矿化受构造及岩体联合控制,为构造斑岩蚀变型金矿床。 相似文献
3.
In situ zircon U–Pb ages and Hf isotopic compositions and whole rock geochemical and Sr–Nd–Pb isotopic data are presented for the Zijinshan alkaline intrusive complex from the Shanxi Province, western North China Craton. Salic rocks dominate the complex with the monzonite occurring in the outermost and pseudoleucite phonolitic breccia in the center. The intrusion took place 127 Ma ago with the earliest emplacement of monzonite and the termination of cryptoexplosive pseudoleucite phonolitic breccia. All rocks from this complex show LREE enrichment and HFSE depletion and exhibit enriched to depleted Sr–Nd isotopic features. The presence of inherited zircons and enriched Hf isotopic compositions in zircon rims, along with the enriched whole rock Sr–Nd isotopic compositions, indicate that the monzonite was formed through the mixing of lithospheric mantle-derived magma with lower crust-derived melts. The diopside syenite and nepheline-bearing diopside syenite are more depleted than the monzonite in terms of the Sr and Nd isotopes, together with their very high concentrations of LILE, we proposed that they originated from a mixed mantle source of enriched lithospheric mantle and depleted asthenosphere. The nepheline syenite has very low concentrations of MgO, Ni, Cr, suggesting that the magma underwent significant crystal fractionation. The most depleted Sr and Nd isotopic compositions ((87Sr/86Sr)i = 0.7036–0.7042, εNd(t) = − 0.2–0.3) among all rock types indicate a great contribution of asthenosphere to the nepheline syenite. The Zijinshan complex and its related crust-mantle interaction occurred in an extensional environment which resulted in continuously asthenospheric upwelling. Such an extensional environment might have been developed during the post-orogenic stage of the Late Paleozoic amalgamation of North China Craton with Mongolian continents and subsequent Mongol–Okhotsk ocean closure. 相似文献
4.
5.
邯邢地区燕山期侵入岩系的稀土元素特征 总被引:3,自引:1,他引:3
邯邢地区燕山期侵入岩系的侵入活动发生在109~171Ma之间。它们可以划分成角闪橄辉岩系,角闪闪长岩系,二长岩系和正长岩系四个岩石系列。不同岩系的稀土元素特征表明,它们并不是由同源岩浆演化所成,每个岩系内部稀土元素丰度的变化受岩浆演化过程中分离结晶的矿物种类和数量所制约。角闪闪长岩中的稀土元素主要分配到角闪石中,而角闪二长岩和黑云辉石正长岩中的稀土元素,主要分配到其中的副矿物中。 相似文献
6.
The zircon U-Pb SHRIMP technique was applied to measure the age of the monzonite granite-porphyry from the Bangpu porphy deposits in the eastern Gangdese porphyry belt. It was obtained that the 206Pb/238 U mean age is 13. 9 ±0. 3 Ma (MSWD = 3. 05), which belongs to the late period of Himalaya. The Bangpu monzonite granite-porphyry was formed during the period of ore-bearing porphyries forming in the Gangdese metallogenic belt to the extension environment of post-collision (12-18 Ma). Our new data suggest that the Bangpu monzonite granite-porphyry shared similar metallogenic dynamics settings to the Gangdese copper belt, which belongs to a rapid outbreak of large-scale mineralization process. Our new result is very important in confirming the active time of the Gangdese magma, provides chronological data and new inspiration for evolution studies of the whole Gangdese metallogenic belt. 相似文献
7.
朝鲜半岛中南部三叠纪岩浆岩的分布、系列与成因浅析 总被引:1,自引:1,他引:0
朝鲜半岛发育大量三叠纪侵入体,主要分布在半岛中部一个北东向走廊地带,该带状区域根据岩性差异,以洪城-高城一线为界分为两个亚带:北亚带(正长岩带/碱性岩带)主要分布在狼林地块南部及京畿地块北部,为碱性系列,以正长岩类为主;南亚带(二长岩带)主要分布在京畿地块南部-岭南地块,多为亚碱性系列,以(纹长)二长岩类为主,部分岩体有闪长岩-辉长岩端元,南部有少量A型花岗岩。这些岩体多形成于ca.230~220Ma,如本文获得的北亚带江北黑云母正长岩228.7±0.8 Ma锆石U-Pb谐和年龄。它们与本区高级变质作用时代接近,分布范围大致对应但稍大,说明它们是同成因的。岩石化学方面,这些岩体均显示高场强元素亏损,轻稀土和大离子亲石元素富集的典型的大陆岩石圈特征。南北亚带相比,北亚带岩体SiO_2和Na_2O等的含量整体上略低,而K_2O、Sr、Ba、La、Eu、Y、Cr等及稀土元素含量略高,轻重稀土分异程度((La/Yb)N)略高。空间上,两个亚带内K_2O/Na_2O和SiO_2有相反的变化趋势:从南向北,两个亚带内K_2O/Na_2O逐渐升高,SiO_2含量逐渐降低;但K_2O+Na_2O和Sr/Y的变化是相似的:南亚带从南向北,北亚带从北向南,两者逐渐降低。我们认为这些岩浆岩为同碰撞或者碰撞后产物,两个亚带之间的界线接近华北和华南古陆缝合带,岩性和成分的空间差异受控于华南古陆(朝鲜半岛南部)向华北古陆(朝鲜半岛北部)之下俯冲所形成的特定壳幔结构。 相似文献
8.
云掌寨铁矿区地质条件复杂,控矿因素较多,通过分析认为受“层、相、位”控制,地层初始富集,构造及岩浆活动提供通道及热源,热液驱动作用下在构造有利部位成矿. 相似文献
1