Magma Mingling in Kimberlites: Evidence from the Groundmass Cocrystallization of Two Spinel-Group Minerals
Magma Mingling in Kimberlites: Evidence from the Groundmass Cocrystallization of Two Spinel-Group Minerals
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金伯利岩中的岩浆混合：来自两种尖晶石族矿物的基质共结晶的证据
DOI：
10.3390/min10090829
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发表时间：
2020-09
期刊：
影响因子：
2.5
通讯作者：
Castillo-Oliver Montgarri
中科院分区：
文献类型：
--
作者：
Xu Jingyao;Melgarejo Joan Caries;Li Qiuli;Abat Lisard Torro I;Castillo-Oliver Montgarri
我们提出了一个详细的岩相学研究的结果，新鲜连贯的样品的梅诺米尼金伯利岩采样在网站73，位于梅诺米尼县，密歇根州，美国。我们的目标是解释其不寻常的和复杂的共生序列。几代橄榄石，钛铁矿，尖晶石类矿物进行了描述。早期橄榄石和钛铁矿为捕虏晶，被原生矿物取代或过度生长。橄榄石的带状微晶有一个包晶核，由第一边缘覆盖，其中金红石，钙钛矿和尖晶石s.s.（严格意义上的尖晶石）共结晶。一个原生金红石微晶的原位U-Pb测年结果为168.9 ± 4.4Ma，为侵位年龄。基质由橄榄石、尖晶石组成，一种镁钙钛矿-钙钛矿-磁铁矿（MUM）尖晶石、方解石和白云石。尖晶石的结晶表明Si的活性极低而不是金云母二水硬铝石微晶的存在表明高活动的Cl和S在熔融结晶的后期阶段。两种不同的尖晶石族矿物（尖晶石s.s.和富含镁橄榄石的MUM）被解释为镁碳酸岩熔体与占主导地位的金伯利岩熔体混合的明确证据。
We present the results of a detailed petrographic study of fresh coherent samples of the Menominee kimberlite sampled at site 73, located in Menominee County, MI, USA. Our objective is to account for its unusual and complex paragenetic sequence. Several generations of olivine, ilmenite, and spinel-group minerals are described. Early olivine and ilmenite are xenocrystic and were replaced or overgrown by primary minerals. Zoned microcrysts of olivine have a xenocrystic core mantled by a first rim in which rutile, geikielite, and spinel s.s. (spinel sensu stricto) cocrystallized. The in situ U–Pb dating of a microcryst of primary rutile yielded 168.9 ± 4.4 Ma, which was interpreted as the age of emplacement. The groundmass consists of olivine, spinel s.s., a magnesian ulvöspinel–ulvöspinel–magnetite (MUM) spinel, calcite, and dolomite. An extremely low activity of Si is suggested by the crystallization of spinel s.s. instead of phlogopite in the groundmass. The presence of djerfisherite microcrysts indicates high activities of Cl and S during the late stages of melt crystallization. The occurrence of two distinct spinel-group minerals (spinel s.s. and qandilite-rich MUM) in the groundmass is interpreted as clear evidence of the mingling of a magnesiocarbonatitic melt with a dominant kimberlitic melt.
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影响因子：
3.9
作者：
Yue-heng Yang;Fu-Yuan Wu;S. Wilde;Xiaoming Liu;Y. Zhang;Liewen Xie;Jin-Hui Yang
通讯作者：
Yue-heng Yang;Fu-Yuan Wu;S. Wilde;Xiaoming Liu;Y. Zhang;Liewen Xie;Jin-Hui Yang
影响因子：
3.5
作者：
E. S. Mcgee;B. C. Hearn
通讯作者：
E. S. Mcgee;B. C. Hearn
影响因子：
56.9
作者：
L. Fuchs
通讯作者：
L. Fuchs
影响因子：
2.1
作者：
A. Logvinova;R. Wirth;E. Fedorova;N. Sobolev
通讯作者：
A. Logvinova;R. Wirth;E. Fedorova;N. Sobolev
影响因子：
0.9
作者：
A. Golovin;V. Sharygin;N. Pokhilenko;V. Malkovets;B. Kolesov;N. Sobolev
通讯作者：
A. Golovin;V. Sharygin;N. Pokhilenko;V. Malkovets;B. Kolesov;N. Sobolev