Immiscible hydrous Fe-Ca-P melt and the origin of iron oxide-apatite ore deposits.
Immiscible hydrous Fe-Ca-P melt and the origin of iron oxide-apatite ore deposits.
复制标题
不混溶水合Fe-Ca-P熔体及氧化铁-磷灰石矿床的成因
DOI：
10.1038/s41467-018-03761-4
复制
发表时间：
2018-04-12
影响因子：
16.6
通讯作者：
Namur O
中科院分区：
文献类型：
--
作者：
Hou T;Charlier B;Holtz F;Veksler I;Zhang Z;Thomas R;Namur O
氧化铁-磷灰石矿床的起源是有争议的。硅酸盐液体的不可渗透性和富铁熔体的分离已经被调用，但在天然或合成岩浆系统中从未观察到与矿石成分相似的富Fe-Ca-P和贫Si熔体。在这里，我们报告了在100 MPa，1000 - 1040 ° C，氧逸度条件（fO2）为100 FMQ = 0.5 - 3.3（FMQ =铁橄榄石-磁铁矿-石英平衡）下发展液体不可渗透性的中间岩浆的实验。一些不混溶的熔体高度富集铁和磷±钙，并且强烈贫硅（<5重量% SiO2）。这些贫硅熔体与流纹岩共轭体处于平衡状态，并在氧化条件下（~FMQ +3.3）、高水活度（aH2O ≥ 0.7）和含氟体系（1 wt. %）中产生。研究结果表明，aH_2O和fO_2的增加使双液场扩大，从而使Fe-Ca-P熔体更容易从寄主岩浆中分离出来，生成氧化铁-磷灰石矿石。氧化铁-磷灰石矿床的成因至今仍是一个谜，也是一个有争议的问题。本文通过对中间岩浆的实验研究表明，aH_2O和fO_2的增加使双液场扩大，从而使Fe-Ca-P熔体更容易从寄主岩浆中分离出来，生成氧化铁-磷灰石矿石。
The origin of iron oxide-apatite deposits is controversial. Silicate liquid immiscibility and separation of an iron-rich melt has been invoked, but Fe–Ca–P-rich and Si-poor melts similar in composition to the ore have never been observed in natural or synthetic magmatic systems. Here we report experiments on intermediate magmas that develop liquid immiscibility at 100 MPa, 1000–1040 °C, and oxygen fugacity conditions (fO2) of ∆FMQ = 0.5–3.3 (FMQ = fayalite-magnetite-quartz equilibrium). Some of the immiscible melts are highly enriched in iron and phosphorous ± calcium, and strongly depleted in silicon (<5 wt.% SiO2). These Si-poor melts are in equilibrium with a rhyolitic conjugate and are produced under oxidized conditions (~FMQ + 3.3), high water activity (aH2O ≥ 0.7), and in fluorine-bearing systems (1 wt.%). Our results show that increasing aH2O and fO2 enlarges the two-liquid field thus allowing the Fe–Ca–P melt to separate easily from host silicic magma and produce iron oxide-apatite ores. The origin of iron oxide-apatite deposits remains enigmatic and controversial. Here, the authors perform experiments on intermediate magmas and show that increasing aH2O and fO2 enlarges the two-liquid field thus allowing the Fe–Ca–P melt to separate easily from host silicic magma and produce iron oxide-apatite ores.
登录
查看更多内容
影响因子：
64.8
作者：
Burgisser, Alain;Scaillet, Bruno
通讯作者：
Scaillet, Bruno
影响因子：
3.5
作者：
Charlier, Bernard;Grove, Timothy L.
通讯作者：
Grove, Timothy L.
影响因子：
5
作者：
Gleason, JD;Marikos, MA;Johnson, DA
通讯作者：
Johnson, DA
影响因子：
5
作者：
Hou, Tong;Charlier, Bernard;Holtz, Francois
通讯作者：
Holtz, Francois
影响因子：
4.6
作者：
Jonsson, Erik;Troll, Valentin R.;Hogdahl, Karin;Harris, Chris;Weis, Franz;Nilsson, Katarina P.;Skelton, Alasdair
通讯作者：
Skelton, Alasdair