| 作成者 |
|
|
|
|
|
|
|
|
|
| 本文言語 |
|
| 出版者 |
|
| 利用開始日 |
|
| 発行日 |
|
| 収録物名 |
|
| 巻 |
|
| 開始ページ |
|
| 出版タイプ |
|
| アクセス権 |
|
| 関連DOI |
|
| 関連HDL |
|
| 概要 |
The Wigu Hill Carbonatite is a rare-earth element (REE) deposit characterized by NW-SE and NE-SW dikes. This study combines field observations, petrography, X-ray diffractometry (XRD), X-ray fluoresce...nce Spectroscopy (XRF), and laser ablation ICP-MS in order to understand the formation processes of the carbonatite dikes and the associated REE mineralization. The study outlines three stages in Wigu Hill Carbonatite formation: (1) the magmatic stage that includes magnetite-dolomite (Mag-Dol), apatite-dolomite (Ap-Dol), and the brecciated apatite-dolomite (brecciated Ap-Dol) carbonatites; (2) the transitional (brine-melt) stage, which includes synchysite-bastnäsite-dolomite (Syn-Bsn-Dol) and monazite-dolomite 1 (Mnz-Dol_1) carbonatites, which form by replacing the hexagonal precursor phases, and (3) the carbo-hydrothermal stage, which includes monazite-dolomite carbonatite 2 (Mnz-Dol_2) without hexagonal precursor phases. Geochemical data show that Mag-Dol has low concentrations of total light rare earth elements (∑LREE) (<0.05 wt%) and total REE oxides (TREE_2O_3) (<0.1 wt%). In contrast, Ap-Dol has higher contents with ∑LREE at 0.3 wt% and TREE_2O_3 at 0.5 wt%. The brecciated Ap-Dol contains ∑LREE at 1.1 wt% and TREE_2O_3 at 1.6 wt%. The Syn-Bsn-Dol contains ∑LREE at 8.9 wt% and TREE_2O_3 at 12.3 wt%. Similarly, Mnz-Dol_1 contains ∑LREE at 9.1 wt% and TREE_2O_3 at 12.6 wt%, marginally exceeding the Syn-Bsn-Dol. The Mnz-Dol_2 has ∑LREE at 6.3 wt% and TREE_2O_3 at 7.4 wt%. The REE mineralization occurred due to magmatic differentiation processes, which intensified from magmatic to transitional (brine-melt) stages, involving (1) differentiation of primary carbonatitic melts, (2) dissolution and replacement of hexagonal precursor phases, and (3) redistribution of dissolved REE into insoluble phases such as monazite.続きを見る
|
Mendeley出力
