什么是高场强和大离子亲石元素或者HFSE &李尔LILE (HFS)元素?- 江南体育网页版- - - - -地球科学堆江南电子竞技平台栈交换 最近30从www.hoelymoley.com 2023 - 07 - 09 - t20:52:40z //www.hoelymoley.com/feeds/question/2950 https://creativecommons.org/licenses/by-sa/4.0/rdf //www.hoelymoley.com/q/2950 13 什么是高场强和大离子亲石元素或者HFSE &李尔LILE (HFS)元素? Gimelist //www.hoelymoley.com/users/725 2014 - 12 - 04 - t07:29:44z 2018 - 01 - 28 - t11:31:02z < p >有两组元素经常提到当讨论不兼容的微量元素。他们是高场强元素(HFS中或HFSE)和大离子亲石元素(LIL或LILE)。< / p > < p >这些组织是什么?他们是如何用于地球化学和岩石学? < / p > //www.hoelymoley.com/questions/2950/-/2951 # 2951 11 Gimelist回答的是什么高场强和大离子亲石元素或者HFSE &李尔LILE (HFS)元素? Gimelist //www.hoelymoley.com/users/725 2014 - 12 - 04 - t07:30:08z 2018 - 01 - 28 - t11:31:02z < p > <强>首先,一个简短的介绍不相容元素< /强> < / p > < p >地幔主要是由矿物橄榄石、辉石,钙长石、尖晶石、石榴石。这些矿物质是由元素硅、铝、铁、镁和钙。下面的图我已经把它们放在MRFE字段(地幔岩石形成元素)。微量元素,元素出现在非常低的浓度,不形成自己的矿物质,而是纳入常见矿物的晶格。很容易在这样的元素共享半径和电荷的主要元素,因为它们可以很容易地适应晶格(例如倪在橄榄石、铬在斜辉石)。< / p > < p >大多数元素,然而,情节出图中的MRFE字段,被认为是不相容元素。在地幔中融化,这些不相容元素分区到岩浆和最终迁移时形成新的岩石(例如玄武岩)。因为不同的流程和地幔熔融条件导致不同的模式和内容的不相容元素在新岩石,我们可以了解地幔过程通过研究这些元素更容易融化岩石(如玄武岩火山)。< / p > < p >请注意,我指的是不相容元素对地幔矿物相矛盾的。在某些地壳岩石K, Na和Ti成为主要元素。在这种情况下,MRFE应该改名为CRFE(地壳造岩元素)和扩大到包括这些元素。< / p > < p > < img src = " https://i.stack.imgur.com/RXCuD.png " alt = "微量元素" > < / p > < p > <强> HFSE和LILE < /强> < / p > < p >然后不相容元素分为两组:高场强元素(HFS中或HFSE)和大离子亲石元素(LIL或LILE)。< / p > < p >李尔名称部分赠送他们为什么叫这样:李尔确实比其他阳离子。亲石元素,它们是不相容的,通常最终浓缩在地壳(岩石圈)。

The HFS are also enriched in the crust (eventually) but their name derives from their small radius compared to their high cationic charge: the z/r ratio. As a result, their bonding to nearby anions is very strong, that is - they have a high electrical field strength.

The subdivision between the two groups has been defined at z/r = 2.0, but as this is a continuous value, no strict theoretical definition of where the boundary lies can be given. Historically, the REE have been considered as LIL. In more modern times, the REE may be excluded when discussing HFS.

Why do we need the two groups?

Even though both the LILE and HFSE behave in an incompatible way during mantle melting, their response to post-magmatic processes differ. The HFSE are usually immobile: that is, they are mostly resistant to metamorphism and hydrothermal alteration. On the other hand, the LILE are fluid-mobile and hydrothermal alteration may change their contents in the studied rock.

Fresh rocks are a scarce luxury and many rocks that we study have experienced some kind of alteration. Because HFSE are resistant to these processes, their contents are likely to be representative of the original rock. This is extremely important: it is possible to look at a rock beyond the altered mineral composition and the modified major element contents. The LIL can teach us the opposite - we can learn about the alteration processes. If we do find fresh rocks and we find anomalies in the LIL systematics, we can learn about hydrothermal processes that occurred in the mantle that would otherwise not be able to see.

What about hexavalent cations?

One would think that hexavalent cations such as Mo6+, Cr6+, V6+ and U6+ should also appear in the figure as cations with an even more HFS character. However, when in the hexavalent state they form anionic complexes and do not behave like the cations in the figure.

Further reading

MIT OpenCourseWare - Trace-Element Geochemistry

The Use of Trace Elements in Igneous Petrology

About the figure

Inspired by figure 2.2 from Ore Deposit Geology / Scott. Data for figure from An Earth Scientist's Periodic Table of the Elements and Their Ions (also doi)
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