摘要
沙柳泉铌钽矿床大地构造位置位于柴达木盆地北缘台缘褶皱带东缘,隶属欧龙布鲁克-乌兰钨（铁、铋、稀有、稀土、宝玉石）成矿带中。区内伟晶岩脉成群出露,伟晶岩脉多穿层侵入于达肯大坂群大理岩段（Pt1D2）中,大理岩段为区内主要赋矿层位。钾长伟晶岩中ΣREE=2.77×10-6-4.34×10-6,平均为3.44×10-6;LREE/HREE=1.37-3.57,平均为2.10;（La/Yb）N为1.00-8.68,平均为2.92;（La/Sm）N为0.63-3.41,平均1.39;显示轻重稀土分馏明显,具轻稀土富集性特征;多数样品Eu、Ce略显负异常;在Rb-Y＋Nb伟晶岩源区及成岩过程图中样品投点于上地壳源区。达肯大坂（岩）群大理岩段岩石类型属低角闪岩相,断裂构造较为发育,可能有来自深部热流体的参与和混合;在后期重结晶和交代作用下,形成白云母花岗伟晶岩。由此,沙柳泉地区伟晶岩可能具有壳源变质分异叠加混合交代形成伟晶岩的特征。
The Shaliuquan niobium- tantalum deposit is located in the eastern edge of the fold,the northern margin of Qaidam Basin,and belongs to Oulongbuluke- Ulan tungsten（ iron,bismuth,rare,rare,gem stone） metallogenic belt.Pegmatite occurs in groups,and intrudes cross- layered in Dakendaban gneiss group（ Pt1D1）,marble section is the main ore- bearing layer. K- feldspar pegmatite shows ΣREE = 2. 77 × 10- 6~ 4. 34 × 10- 6（ an average of 3. 44 × 10- 6）,LREE/HREE = 1. 37 ~ 3. 57（ an average of 2. 10）,（ La / Yb）N= 1. 00 ~ 8. 68（ an average of 2. 92） and（ La / Sm）N= 0. 63 ~ 3. 41（ an average of 1. 39）,displays distinct fractionation between LREE and HREE,with enrichment of LRE,and most samples show slightly negative Eu,Ce anomalies. Samples fall within in the crustal source in Rb- Y ＋ Nb pegmatite source and diagenesis diagram. Marble section in Dakendaban group is low amphibolite facies,and may derived from the involvement and mixing of deep thermal fluid. It formed muscovite granite pegmatite after the later recrystallization and metasomatism. Thus,we believed the pegmatite is probably from the mixing and metamorphic differentiation of the crust material.
出处
《稀土》
EI
CAS
CSCD
北大核心
2016年第1期39-46,共8页
Chinese Rare Earths
基金
青海三稀资源调查(2012000100630144)
国土资源部公益性行业科研专项(201211037-01)
青海省科技计划项目(2013-Z-011
2014-ZJ-701
J-ZY-7
J-ZY-8)
