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pegmatite n.【礦物】偉晶巖。

pegram

It was found that the schorl or dravite in schorl - dravite group that is produced from pegmatite and has good crystal degree had a strong intensity of spontaneous polarity by electron - beam bombardment and x - ray diffraction of varying the temperature 利用電子束轟擊結合變溫xrd分析發現在schorl - dravite系列電氣石中,產于偉晶巖的,結晶度比較高的mg電氣石或fe電氣石具有較高的自發極化強度。

In order to find new pegmatite nb - ta ore - deposit , it is very important practical - significances to ascertain the host structure characteristics and the relations between the tectonic epochs and ore - forming 通過查明礦床的容礦構造特征以及構造期次與成礦的關系,對尋找新的鈮鉭偉晶巖礦床具有重要的實踐意義。

You can see a vein , like 人 the chinese character , of pegmatite formed about 2 . 6billion years ago intruding in the granodiorites mass formed about 2 . 7billion years ago 26億年前后形成的偉晶巖侵入到27億年前后形成的花崗閃長巖中,形成“人”字形脈體。

Quartz core zones : mineralisation occurs in enclaves of albitisation around the core of the pegmatite . tantalite crystals are large and randomly distributed 石英核心帶:礦化作用存在于被納長石礦包圍的偉晶巖核心。鉭鐵礦呈現巨大而不規則分布。

The pegmatite nb - ta mineral veins were controlled by a group of horizontal tenso - shear axial - direction fault - fissure systems in the nne direction folding structures 鈮鉭偉晶巖礦脈受控于nne向褶皺構造的一組近水平張扭性軸向裂隙系。

Epidote albite pegmatite 綠簾鈉長偉晶巖

Elaeolite - syenite - pegmatite 脂光正長偉晶巖

Epidote orthoclase pegmatite 綠簾正長偉晶巖

Epidote oligoclase pegmatite 綠簾奧長偉晶巖

Corundum oligoclase pegmatite 剛玉奧長偉晶巖

At pegmatite contacts the composition changes to chalcopyrite, millerite, pyrite, and violarite accompanied by magnetite and hematite . 在偉晶巖接觸帶,硫化物成分變為黃銅礦、針鎳礦、黃鐵礦及硫鎳鐵礦,伴生有磁鐵礦和赤鐵礦。

Pegmatites seem to form during a late magmatic stage . 偉晶巖似乎是在較晚的巖漿階段形成的。