从磷灰石稀土元素分配探究花岗岩源区特性

Exploring the Characteristics of the Granite Source Area from the Distribution of Rare Earth Elements in Apatite

摘要: 花岗岩是由岩浆源区经历一系列地质作用形成的，这些岩浆通常来自不同的地壳深部源区，而磷灰石是花岗岩中常见的一种副矿物，具有特殊的地化性质，因此了解磷灰石中稀土元素分配机制对岩浆源区的追踪以及岩浆演化和岩石成岩过程的研究是研究花岗岩成因的关键。本研究通过对相关实验数据和理论分析的研究，揭示了磷灰石的晶体结构和化学组成对稀土元素分配的影响。研究发现，磷灰石中的Ca²⁺和磷酸根基团与稀土元素的离子半径和电荷特征相互作用，从而影响稀土元素在磷灰石中的相容性和分配行为。结合广西花山、姑婆山等地区对磷灰石的研究数据以及前人研究成果，进一步探讨了温度、压力等因素对磷灰石与稀土元素相互作用的影响，为研究稀土元素的分配机制和影响因素以及岩浆源区追踪和演化过程提供理论依据。

Abstract: Granite is formed by a series of geological processes in the magma source area, and these magmas usually come from different deep crustal source areas. Apatite is a common accessory mineral in granite and has special geochemical properties. Therefore, understanding the distribution mechanism of rare earth elements in apatite is the key to studying the genesis of granite for the tracking of the magma source area and the research on the magma evolution and rock diagenesis process. Through the research on relevant experimental data and theoretical analysis, this study reveals the influence of the crystal structure and chemical composition of apatite on the distribution of rare earth elements. It is found that the Ca²⁺ and phosphate groups in apatite interact with the ionic radius and charge characteristics of rare earth elements, thereby affecting the compatibility and distribution behavior of rare earth elements in apatite. Combined with the research data of apatite in areas such as Nanan and Liuchen in Guangxi, as well as the previous research results, the influence of factors such as temperature and pressure on the interaction between apatite and rare earth elements is further discussed, providing a theoretical basis for studying the distribution mechanism and influencing factors of rare earth elements, as well as the tracking and evolution process of the magma source area.