Reedmergnerite and associated minerals from peralkaline pegmatite, Dara-i-Pioz, southern Tien Shan, Tajikistan
Reedmergnerite and associated minerals from peralkaline pegmatite, Dara-i-Pioz, southern Tien Shan, Tajikistan
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塔吉克斯坦天山南部 Dara-i-Pioz 过碱性伟晶岩中的芦苇镁锰矿和伴生矿物
DOI：
10.1127/ejm/5/5/0971
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发表时间：
1993
影响因子：
2.1
通讯作者：
N. Marquez
中科院分区：
文献类型：
--
作者：
E. Grew;D. I. Belakovskiy;M. Fleet;M. Yates;J. Mcgee;N. Marquez
里德麦绿石产于与侏罗纪杂岩有关的伟晶岩中，杂岩以亚碱性花岗岩为主。它在粗石英和微斜长石中形成直径达几厘米的聚集体，并被细颗粒石英的微细脉广泛包围，其中含有少量的微斜长石和副钠长石、霓石、真透闪石、烧绿石、淡白闪石、淡白霞石和锌霞石。较粗的微斜长石被较细的钠长石和含有副玻陨石和霓石的微斜长石的细脉切割。微斜长石为Or 97 -99，含0.02 wt % B 2 O 3 ;钠长石为An 0 -1，含0.005 wt % B 2 O 3。霓石含NaFeSi 2 O 6 83-98摩尔%，NaAlSi 2 O 6 ≤ 5摩尔%，Ca（Mg，Mn）Si 2 O 6 ≤ 10摩尔%，Na（Fe 2+，Mn）0.5Ti0.5Si2O6 ≤ 14摩尔%.聚锂矿的组成为K2Li3.9Al1.6Ti0.24Fe0.1Si4O10F4.里德汞银矿不含含量超过0.05重量%氧化物的杂质。犹他州（型）和塔吉克斯坦的红硫镁矾的平均电子探针分析给出了接近化学计量的NaBSi 3 O 8，而单个分析遵循的趋势是Na + B与Si成反比，Si = 2.91-3.07/分子式单位。在450-500 °C的温度和P ≤ 2 kbar的压力下，对于伟晶岩组合正长石+ Reedmergnerite +石英，Reedmergnerite具有接近理想的B-Si顺序。我们认为，这一组合结晶从一个高碱性，含钠的残留熔体条件下，B饱和达到蒸汽饱和之前，演变
Reedmergnerite occurs in pegmatites associated with a Jurassic complex dominated by subalkaline granitoids. It forms aggregates up to several cm across in coarse quartz and microcline, and is extensively embayed by microveinlets of fine-granular quartz containing minor microcline and accessory albite, aegirine, eudialyte, pyrochlore, leucosphenite, leucophanite and zektzerite. The coarse microcline is cut by microveinlets of finer albite and microcline containing accessory hyalotekite and aegirine. Microcline is Or97-99 with 0.02 wt % B 2 O 3 ; albite is An0-1 with 0.005 wt % B 2 O 3 . Aegirine contains 83-98 mole % NaFeSi 2 O 6 , ≤ 5 % NaAlSi 2 O 6 , ≤ 10 % Ca(Mg,Mn)Si 2 O 6 and ≤ 14 % Na(Fe 2+ ,Mn) 0.5 Ti 0.5 Si 2 O 6 . Polylithionite composition is K 2 Li 3.9 Al 1.6 Ti 0.24 Fe 0.1 Si 4 O 10 F 4 . Reedmergnerite contains no impurities in amounts exceeding 0.05 wt % oxide. Average electron microprobe analyses of reedmergnerite from Utah (type) and Tajikistan give nearly stoichiometric NaBSi 3 O 8 , whereas individual analyses follow a trend whereby Na + B varies inversely with Si for Si = 2.91-3.07 per formula unit. Reedmergnerite had nearly ideal B-Si order at the 450-500 °C temperatures and P ≤ 2 kbar pressures estimated for the pegmatitic assemblage orthoclase + reedmergnerite + quartz. We suggest that this assemblage crystallized from a highly alkaline, sodic residual melt that evolved under conditions whereby B saturation was attained prior to vapor saturation