Related Experiment Video
Updated: Sep 12, 2025
08:55
Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
8.6K
Reaction-driven magmatic crystallisation at the Maoniuping carbonatite
1State Key Laboratory of Deep Earth and Mineral Exploration, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, PR China. ly@cags.ac.cn.
Nature Communications
|August 4, 2025
Summary
The Maoniuping rare earth element (REE) deposit formed magmatically from a carbonatite brine-melt, not hydrothermal fluids. Assimilation of host rock elements drove solidification, a process likely common in other carbonatite-hosted REE deposits.
Area of Science:
- Geology
- Economic Geology
- Petrology
Background:
- Igneous rocks form from magma solidification, with hydrothermal alteration often proposed for mineral deposits.
- The origin of the Maoniuping rare earth element (REE) deposit has been attributed to hydrothermal processes, but direct evidence is lacking.
- Understanding the genesis of REE deposits is crucial for global resource management.
Purpose of the Study:
- To investigate the formation mechanism of the Maoniuping REE deposit.
- To determine the role of magmatic versus hydrothermal processes in REE mineralization.
- To elucidate the solidification process of carbonatite melts in relation to host rock interaction.
Main Methods:
- Detailed textural and chemical analysis of rock samples from the Maoniuping deposit.
- Microscopic examination to identify mineral assemblages and interactions.
- Geochemical investigation of melt-host rock interactions and element assimilation.
Main Results:
- The Maoniuping REE deposit originated from a magmatic carbonatite brine-melt, not hydrothermal fluids.
- Interaction between the carbonatite melt and quartz syenite host produced albitised fenites.
- Coupled metasomatism led to silica contamination, causing melt solidification through the crystallization of refractory silicates (antiskarn) and removal of Na and K.
Conclusions:
- Carbonatite melts can solidify via element assimilation from their environment, a process distinct from simple cooling or volatile exsolution.
- Solidification driven by coupled antiskarnisation and fenitisation influences mineral assemblage and ore fabric.
- This igneous formation process is likely significant for many carbonatite-hosted REE deposits globally.
More Related Videos
11:50Metal-silicate Partitioning at High Pressure and Temperature: Experimental Methods and a Protocol to Suppress Highly Siderophile Element Inclusions
Published on: June 13, 2015
12.6K
11:14Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent
Published on: February 21, 2017
12.5K
Related Concept Videos
01:25Crystal Growth: Principles of Crystallization
2.6K
Crystallization is a phase transformation process in which crystals are precipitated from a supersaturated solution or formed from other sources. During crystallization, atoms or molecules arrange themselves into a well-defined, rigid crystal lattice to minimize energy.
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent...
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent...
2.6K
01:10Recrystallization: Solid–Solution Equilibria
1.2K
Recrystallization is a purification technique used to separate impurities from solid compounds. In this technique, no chemical reactions occur. Instead, it exploits physical properties only, specifically, the solubility differences between the desired compound and impurities, either at a single temperature or at different temperatures, and under other selected conditions. The solid-solution equilibrium (solubility equilibrium) of each component in the solution represents a binary phase...
1.2K
03:46Qualitative Analysis
22.6K
For solutions containing mixtures of different cations, the identity of each cation can be determined by qualitative analysis. This technique involves a series of selective precipitations with different chemical reagents, each reaction producing a characteristic precipitate for a specific group of cations. Metal ions within a group are further separated by varying the pH, heating the mixture to redissolve a precipitate, or adding other reagents to form complex ions.
For instance, group IV...
For instance, group IV...
22.6K
00:52Washing, Drying, and Ignition of Precipitates
1.1K
After filtration, the precipitate is washed to remove coprecipitated impurities and any remaining mother liquor. Colloidal precipitates, such as silver chloride, are washed with an electrolyte (such as dilute nitric acid) to prevent the peptization of the precipitate. In the case of slightly soluble precipitates, the wash solution contains a common ion to reduce solubility. Lead sulfate, which is slightly soluble in water, is washed with dilute sulfuric acid. Similarly, wash solutions may be...
1.1K
02:42Ionic Crystal Structures
14.7K
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
14.7K
02:39Phase Transitions: Melting and Freezing
13.1K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
13.1K