排序方式: 共有6条查询结果,搜索用时 15 毫秒
1
1.
江西足洞和关西花岗岩体的铀—铅,铷—锶体系同位素特征及其地质意义 总被引:4,自引:1,他引:4
江西龙南足洞重稀土和关西轻稀土花岗岩体锆石U-Pb不一致线下交点年龄分别为124和170Ma,分属燕山中期晚阶段和燕山早期岩浆活动产物。综合钾长石铅同位素组成和初始~(87)Sr/~(86)Sr值,可以排除两者作为同源岩浆(封闭或受混染体系)结晶分异演化的可能性。虽然两者的成岩物质均来自上地壳,但足洞岩体可能源于变质沉积岩,而关西岩体则可能由古老的中—基性火成岩派生。计算的μ_0值为8.35—8.38.源区的μ_1值和Th/U值,足洞分别为11.4和4.02,而关西分别为13.6和3.62。上述同位素新数据为南岭地区重、轻稀土花岗岩提供了对比资料。 相似文献
2.
江西足洞和关西花岗岩的岩石学、稀土元素地球化学及成岩机制 总被引:3,自引:0,他引:3
通过对足洞和关西两个岩体形成地质背景、岩石学、岩石稀土元素地球化学、成岩时代、铅和氧同位素组成以及初始锶比值的研究,充分表明,足洞岩体由黑云母钾长花岗岩和白云母钾长-碱长花岗岩组成,是燕山中晚期(124Ma)形成的富HREE花岗岩体;关西黑云母碱长花岗岩则是燕山早期(170Ma)的富LREE花岗岩体。前者的特征相当于S型花岗岩,后者相当于兼有S型特征的Ⅰ型花岗岩。由于成岩的源岩性质、再生岩浆REE含量和配分以及自交代程度的不同,是造成这两个岩体所含重、轻稀土差别的根本原因,同时这种稀土内生地球化学的差异, 相似文献
3.
5.
6.
从赣南地层含钨丰度看地层对钨矿的控制 总被引:1,自引:0,他引:1
Among various factors governing the formation of tungsten ore deposits, the stratigraphic condition is considered as an important one. The formation of tungsten ore deposits is stratigraphically controlled in many ways, for example, to provide ore-forming materials by every possible means;for tungsten deposits is regarded as a most important stratigraphic control over tungsten mineralization. 150 quantitative analyses show that tungsten abundances are generally high in preJurassic strata in southern Jiangxi, thus providing a favourable material basis for tungsten mineralization. In the studied area, the Yenshanian granites related to tungsten mineralization are products of remelting of the original pre-Cambrian strata. This suite of strata,together with altered part during the intrusion of granitic magma, contain more tungsten relative to the younger strata, constituting the main source of tungsten for the tungsten ore deposits related to the granite bodies. Moreover, under favourable geological conditions, tungsten may become activated and transported into ore bodies. This is also another important source of tungsten. And on the other hand, this source of tungsten may constrain, to a certain degrce, the stratigraphic position of tungsten ore deposits. 相似文献
1