标题： 磷灰石中的硫和稀土元素带状分布：科利阿尔巴尼岩浆系统的例子 显示英文标题

标题： Sulfur and REE zoning in apatite: The example of the Colli Albani magmatic system

摘要： 我们研究了赋存于主要由霞石和斜方辉石组成的碎屑碱性岩中的磷灰石晶体中主要元素和微量元素的分布情况，这些岩石代表了第四纪超钾质阿尔巴尼火山区（CAVD）岩浆体的浅成结晶作用，该岩浆体侵入到意大利第勒尼安海边缘的厚层石灰岩单元中。 结果表明，所分析的晶体是意大利碱性岩中SrO含量最高的氟磷灰石（高达4.6 wt%），氟含量为2.6-3.7 wt%。锶的富集是由于这些含有霞石和斜方辉石的岩石中缺乏其他与锶相容的矿物相，如斜长石、碱性长石和钙钛矿。 所研究的样品显示出核-边结构，边部富集Si、S和稀土元素（REE），而核心则富集Ca和P。磷灰石中的LREE氧化物含量高达4.2 wt%，占总稀土元素预算的95%以上；SiO2含量范围为1.3至3.6 wt%，SO3浓度在0.6至1.4 wt%之间。 显示英文摘要

摘要： We investigate the distribution of major and trace elements in apatite crystals hosted in granular alkaline rocks composed mainly of leucite and clinopyroxene, representative of the hypabyssal crystallization of a magma body in the Quaternary ultra-potassic Colli Albani Volcanic District (CAVD), which was emplaced into thick limestone units along the Tyrrhenian margin of Italy. Results show that the analyzed crystals are the SrO-richest (up to 4.6 wt%) fluorapatite (F =2.6-3.7 wt%) of the Italian alkaline rocks. The strontium enrichment is caused by the lack of other Sr-compatible mineral phases, such as plagioclase, alkali feldspar and melilite, in these leucite- and clinopyroxene-bearing rocks. The studied samples show core-rim zoning with rims enriched in Si, S, and REE whereas the cores are enriched in Ca and P. The LREE-oxides contents of apatite, reaching 4.2 wt%, represent more than 95% of the total REE budget; SiO2 contents range from 1.3 to 3.6 wt%, and SO3 concentrations between 0.6 and 1.4 wt%.