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Linking the Siberian Flood Basalts and Giant Ni‐Cu‐PGE Sulfide Deposits at Norilsk
Journal of Geophysical Research: Solid Earth ( IF 3.9 ) Pub Date : 2021-02-19 , DOI: 10.1029/2020jb020823
Zhuo‐sen Yao 1 , James E. Mungall 1
Affiliation  

The world‐class magmatic sulfide deposits in the Norilsk region exhibit a remarkable spatial and temporal association with the Siberian large igneous province (LIP). However, the details of the causal connection between the Siberian LIP and the ore deposits have remained contentious. Here we address the problem by modeling of assimilation, crystallization and flow behavior of magmas based on aggregated data from the Norilsk camp. Crustal assimilation at depth by mantle‐derived picritic magma can account for the compositional and isotopic variations of the early tholeiitic basalts and the sequestering of sulfide liquid in a mid‐crustal conduit system. When the rate and volume of asthenospheric magma production dramatically increased, the metal tenors of the mid‐crustal sulfide reservoir were first upgraded by consequent reaction with the fresh, undepleted magmas, then entrained and flushed to higher crustal levels. The resulting sulfide‐rich emulsions were too dense to reach the surface to form lavas but were instead emplaced in multiple pulses within blind sill‐like bodies at shallow depth. Sulfide ores transported from the mid‐crust were deposited at the bases of the upper‐crustal sills, where sedimentary host rocks were assimilated wholesale by the already sulfide‐charged replenishing magmas; this shallow assimilation was itself not instrumental in forming the ores. Although the evolution and dynamics of flood basalts are thus inextricably linked with coeval subvolcanic economic intrusions, the mineralization itself is argued not to occupy feeders with direct links to the overlying lavas, suggesting major implications for exploration in other LIPs.

中文翻译:

将诺里尔斯克的西伯利亚洪水玄武岩与巨型Ni-Cu-PGE硫化物矿床联系起来

诺里尔斯克地区的世界级岩浆硫化物矿床与西伯利亚大火成岩省(LIP)表现出明显的时空关联。但是,关于西伯利亚LIP与矿床之间因果关系的细节仍然存在争议。在这里,我们基于来自Norilsk阵营的汇总数据,通过对岩浆的同化,结晶和流动行为进行建模来解决该问题。地幔衍生的岩浆岩浆对地壳的深度同化作用可以解释早期冲孔玄武岩的组成和同位素变化以及中地壳管道系统中的硫化物固存。当软流圈岩浆产量的速率和体积急剧增加时,中地壳硫化物储层的金属ten度首先通过与新鲜的,未耗尽的岩浆,然后夹带并冲至更高的地壳水平。所得的富含硫化物的乳状液太稠密,无法到达表面形成熔岩,而是在浅深度的盲基状体中以多个脉冲的形式存在。从中地壳运来的硫化矿石被沉积在上地壳基岩的基部,那里的沉积基质岩被已经充有硫化物的补充岩浆大量吸收。这种浅浅的同化本身并不能帮助形成矿石。尽管洪水玄武岩的演化和动力学因此与近代次火山岩的经济入侵密不可分,但据认为矿化本身不会占据与上覆熔岩有直接联系的馈线,这暗示了对其他LIP勘探的重大意义。然后夹带并冲至更高的地壳水平。所得的富含硫化物的乳状液太稠密,无法到达表面形成熔岩,而是在浅深度的盲基状体中以多个脉冲的形式存在。从中地壳运来的硫化矿石被沉积在上地壳基岩的基部,那里的沉积基质岩被已经充有硫化物的补充岩浆大量吸收。这种浅浅的同化本身并不能帮助形成矿石。尽管洪水玄武岩的演化和动力学因此与近代次火山岩的经济入侵密不可分,但据认为矿化本身不会占据与上覆熔岩有直接联系的馈线,这暗示了对其他LIP勘探的重大意义。然后夹带并冲至更高的地壳水平。所得的富含硫化物的乳状液太稠密,无法到达表面形成熔岩,而是在浅深度的盲基状体中以多个脉冲的形式存在。从中地壳运来的硫化矿石被沉积在上地壳基岩的基部,那里的沉积基质岩被已经充有硫化物的补充岩浆大量吸收。这种浅浅的同化本身并不能帮助形成矿石。因此,尽管洪水玄武岩的演化和动力学与近代次火山岩的经济入侵有着千丝万缕的联系,但据认为矿化本身并不占据与上覆熔岩有直接联系的馈线,这暗示着对其他LIP勘探的重大意义。生成的富含硫化物的乳状液太稠密,无法到达表面形成熔岩,而是在浅深度的呈台阶状的基体中以多个脉冲的形式存在。从中地壳运来的硫化矿石被沉积在上地壳基岩的基部,那里的沉积基质岩被已经充有硫化物的补充岩浆大量吸收。这种浅浅的同化本身并不能帮助形成矿石。尽管洪水玄武岩的演化和动力学因此与近代次火山岩的经济入侵密不可分,但据认为矿化本身不会占据与上覆熔岩有直接联系的馈线,这暗示了对其他LIP勘探的重大意义。所得的富含硫化物的乳状液太稠密,无法到达表面形成熔岩,而是在浅深度的盲基状体中以多个脉冲的形式存在。从中地壳运来的硫化矿石被沉积在上地壳基岩的基部,那里的沉积基质岩被已经充有硫化物的补充岩浆大量吸收。这种浅浅的同化本身并不能帮助形成矿石。尽管洪水玄武岩的演化和动力学因此与近代次火山岩的经济入侵密不可分,但据认为矿化本身不会占据与上覆熔岩有直接联系的馈线,这暗示了对其他LIP勘探的重大意义。
更新日期:2021-03-18
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