DYSPROSIAN XENOTIME-(Y) FROM THE ANNIE CLAIM #3 GRANITIC PEGMATITE, SOUTHEASTERN MANITOBA, CANADA: EVIDENCE OF THE TETRAD EFFECT?
DYSPROSIAN XENOTIME-(Y) FROM THE ANNIE CLAIM #3 GRANITIC PEGMATITE, SOUTHEASTERN MANITOBA, CANADA: EVIDENCE OF THE TETRAD EFFECT?
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DOI：
10.2113/gscanmin.38.4.899
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发表时间：
2000-08
影响因子：
0.9
通讯作者：
Morgan Masau;P. Černý;R. Chapman
中科院分区：
文献类型：
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作者：
Morgan Masau;P. Černý;R. Chapman
在马尼托巴省东南部太古宙鸟河亚省伟晶花岗岩的格里尔湖侵入体中，在Annie Claim#3号锂云母亚型花岗伟晶岩中发现了Dysprosian xiotime-(Y)。它以显微包裹体和离散晶体的形式赋存于辉石中，两者都包裹在铁质白云母中，也与锰钴铀矿-锰钽矿、微晶石、锆石和磷灰石共生。辉石-(Y)中Dy含量高达14.88wt.%Dy_2O_3(和7.59 wt.%Gd_2O_3，3.31 wt.%Tb_2O_3)，是迄今在该矿物中观察到的最高Dy含量。在球粒陨石标准化的稀土配分模式中，Tb的正异常甚至高于Dy。与来自其他花岗伟晶岩、蚀变花岗岩和高山脉的Xen-Time-(Y)和Xe-Te-(Yb)一起，Annie主张#3 Xe-Time-(Y)显示出明显的Gd-Lu序列的双重分段，一些作者将其归因于由水介质产生或影响的地质物中的四元效应。分析问题不能在异种时间样品中产生这种影响。
Dysprosian xenotime-(Y) was found in the Annie Claim #3 pod of lepidolite-subtype granitic pegmatite within the Greer Lake intrusion of pegmatitic granite, in the Archean Bird River Subprovince of the Superior Province, in southeastern Manitoba. It occurs as microscopic inclusions in spessartine and as discrete crystals, both enclosed in ferroan muscovite, also associated with manganocolumbite – manganotantalite, microlite, zircon and apatite. The xenotime-(Y) contains up to 14.88 wt.% Dy 2 O 3 (and 7.59 wt.% Gd 2 O 3 , 3.31 wt.% Tb 2 O 3 ), the highest concentration of Dy so far observed in this mineral. In chondrite-normalized REE patterns, the positive Tb anomaly is even higher than that of Dy. Along with xenotime-(Y) and xenotime-(Yb) from other granitic pegmatites, altered granites and alpine veins, the Annie Claim #3 xenotime-(Y) shows prominent double segmenting of the Gd to Lu sequence, ascribed by some authors to the tetrad effect in geological materials generated from, or affected, by aqueous media. Analytical problems could not produce this effect in the xenotime samples.