Details
| Original language | English |
|---|---|
| Article number | 122085 |
| Number of pages | 15 |
| Journal | Chemical geology |
| Volume | 655 |
| Early online date | 6 Apr 2024 |
| Publication status | E-pub ahead of print - 6 Apr 2024 |
Abstract
Carbonatites and their comagmatic silicate rocks related deposit provide significant resources of rare earth elements (REEs), niobium (Nb) and other elements such as U, Th, Mo, V, Ba, Sr, etc. However, the genesis of mineralization, especially for REEs and Nb, in carbonatite remains enigmatic. Previous liquid immiscibility experiments have demonstrated that both REEs and Nb are preferentially enriched in the silicate conjugate instead of carbonate melts under anhydrous conditions. Nevertheless, ligands other than carbonate ion appear to be abundant due to ubiquity of apatite, baryte, celestine, fluorite and sodalite in carbonate–silicate magmatic systems. Here, we experimentally investigate the trace element partitioning between natrocarbonate and silicate (nephelinite) melts in systems doped with varying amounts of additional F−, PO43−, Cl−, and SO42− ligands (0, 2, 4 and 6 wt%) to understand and constrain the role of ligands. The experiments were conducted at 850 °C and 0.1 GPa using rapid quench cold-seal pressure vessels (CSPVs). A comparison of experimental partition coefficients in this study reveals that the significant amounts F− and PO43− incorporated in the silicate melts can increase the D values for REE by influencing melt structure (DLaCM/SM = 0.85–7.42). In contrast, irrespective of the amount of added Cl− and SO42−, DCM/SM is not affected significantly by these species and the DREECM/SM values remain always lower than 1 (DLaCM/SM = 0.12–0.40). Notably, the DNbCM/SM values are all <1, with only one exception containing 6 wt% F. Besides, in all the investigated systems, Ba, Sr, Mo, V, Cs, Rb and Li preferentially partition into the conjugate carbonate melt. All the high field strength elements (Pb, Th, U, Zr, Hf, Nb, Ta), transition metals (Mn, Co, Cu, Zn) and common network formers (Ga, Ge) essentially partition into the silicate melt.
Keywords
- Immiscibility, Ligand, Natrocarbonatite, Nephelinite, Partitioning coefficient
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geology
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
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In: Chemical geology, Vol. 655, 122085, 20.06.2024.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - An experimental study on the role of F−, PO43−, Cl− and SO42− ligands in the natrocarbonatite-nephelinite system at 850 °C and 0.1 GPa
AU - Yang, Dao Ming
AU - Hou, Tong
AU - Botcharnikov, Roman E.
AU - Veksler, Ilya V.
AU - Holtz, Francois
AU - Zhang, Zhaochong
AU - Zhang, Li
AU - Simon, Antonia
AU - Groschopf, Nora
N1 - Funding Information: s. This work was supported by the National Natural Science Foundation of China (91962102 and 42372058), the “Deep-time Digital Earth” Science and Technology Leading Talents Team Funds for the Central Universities for the Frontiers Science Center for Deep-time Digital Earth, China University of Geosciences (Beijing) (Fundamental Research Funds for the Central Universities; grant number: 2652023001), Alexander von Humboldt Fellowship (1207058), National Key Research and Development Program of China (2019YFA0708604-2), and DFG Project Bo2941/8-1.
PY - 2024/4/6
Y1 - 2024/4/6
N2 - Carbonatites and their comagmatic silicate rocks related deposit provide significant resources of rare earth elements (REEs), niobium (Nb) and other elements such as U, Th, Mo, V, Ba, Sr, etc. However, the genesis of mineralization, especially for REEs and Nb, in carbonatite remains enigmatic. Previous liquid immiscibility experiments have demonstrated that both REEs and Nb are preferentially enriched in the silicate conjugate instead of carbonate melts under anhydrous conditions. Nevertheless, ligands other than carbonate ion appear to be abundant due to ubiquity of apatite, baryte, celestine, fluorite and sodalite in carbonate–silicate magmatic systems. Here, we experimentally investigate the trace element partitioning between natrocarbonate and silicate (nephelinite) melts in systems doped with varying amounts of additional F−, PO43−, Cl−, and SO42− ligands (0, 2, 4 and 6 wt%) to understand and constrain the role of ligands. The experiments were conducted at 850 °C and 0.1 GPa using rapid quench cold-seal pressure vessels (CSPVs). A comparison of experimental partition coefficients in this study reveals that the significant amounts F− and PO43− incorporated in the silicate melts can increase the D values for REE by influencing melt structure (DLaCM/SM = 0.85–7.42). In contrast, irrespective of the amount of added Cl− and SO42−, DCM/SM is not affected significantly by these species and the DREECM/SM values remain always lower than 1 (DLaCM/SM = 0.12–0.40). Notably, the DNbCM/SM values are all <1, with only one exception containing 6 wt% F. Besides, in all the investigated systems, Ba, Sr, Mo, V, Cs, Rb and Li preferentially partition into the conjugate carbonate melt. All the high field strength elements (Pb, Th, U, Zr, Hf, Nb, Ta), transition metals (Mn, Co, Cu, Zn) and common network formers (Ga, Ge) essentially partition into the silicate melt.
AB - Carbonatites and their comagmatic silicate rocks related deposit provide significant resources of rare earth elements (REEs), niobium (Nb) and other elements such as U, Th, Mo, V, Ba, Sr, etc. However, the genesis of mineralization, especially for REEs and Nb, in carbonatite remains enigmatic. Previous liquid immiscibility experiments have demonstrated that both REEs and Nb are preferentially enriched in the silicate conjugate instead of carbonate melts under anhydrous conditions. Nevertheless, ligands other than carbonate ion appear to be abundant due to ubiquity of apatite, baryte, celestine, fluorite and sodalite in carbonate–silicate magmatic systems. Here, we experimentally investigate the trace element partitioning between natrocarbonate and silicate (nephelinite) melts in systems doped with varying amounts of additional F−, PO43−, Cl−, and SO42− ligands (0, 2, 4 and 6 wt%) to understand and constrain the role of ligands. The experiments were conducted at 850 °C and 0.1 GPa using rapid quench cold-seal pressure vessels (CSPVs). A comparison of experimental partition coefficients in this study reveals that the significant amounts F− and PO43− incorporated in the silicate melts can increase the D values for REE by influencing melt structure (DLaCM/SM = 0.85–7.42). In contrast, irrespective of the amount of added Cl− and SO42−, DCM/SM is not affected significantly by these species and the DREECM/SM values remain always lower than 1 (DLaCM/SM = 0.12–0.40). Notably, the DNbCM/SM values are all <1, with only one exception containing 6 wt% F. Besides, in all the investigated systems, Ba, Sr, Mo, V, Cs, Rb and Li preferentially partition into the conjugate carbonate melt. All the high field strength elements (Pb, Th, U, Zr, Hf, Nb, Ta), transition metals (Mn, Co, Cu, Zn) and common network formers (Ga, Ge) essentially partition into the silicate melt.
KW - Immiscibility
KW - Ligand
KW - Natrocarbonatite
KW - Nephelinite
KW - Partitioning coefficient
UR - http://www.scopus.com/inward/record.url?scp=85189941161&partnerID=8YFLogxK
U2 - 10.1016/j.chemgeo.2024.122085
DO - 10.1016/j.chemgeo.2024.122085
M3 - Article
AN - SCOPUS:85189941161
VL - 655
JO - Chemical geology
JF - Chemical geology
SN - 0009-2541
M1 - 122085
ER -