Compositional variation of aeschynite-group minerals in the Bayan Obo Nb-REE-Fe ore deposit, Inner Mongolia, China

Z. Yang; Martin Smith; P. Henderson; M.J. Le Bas; K. Tao; P. Zhang

Compositional variation of aeschynite-group minerals in the Bayan Obo Nb-REE-Fe ore deposit, Inner Mongolia, China

Z. Yang, Martin Smith, P. Henderson, M.J. Le Bas, K. Tao, P. Zhang

University of Brighton

Research output: Contribution to journal › Article › peer-review

Abstract

The aeschynite-group minerals occurring in an aegirine-fluorite-dolomite-aeschynite vein in the Bayan Obo Nb-REE-Fe deposit show complex compositional zoning in BSE images. Microprobe analyses revealed that the concentrations of REE₂O₃are globally high in aeschynite-group minerals, ranging from 36.72 to 40.32 wt.%. Four species were identified in the same sample, these being aeschynite-(Ce), aeschynite-(Nd), nioboaeschynite-(Ce) and nioboaeschynite-(Nd). The correlations among cations suggest two special coupled substitutions with charge-balanced described by the exchange vectors as CaNb(Nd,Sm,Pr)_-1Ti_-1 and LaNbTh_-1Ti_-1. The chondrite-normalized REE patterns are hump-shaped with the maximum at Pr or Nd. The chondrite-normalized La/Nd ratios vary in the range ~0.15 to 0.40. It indicates that at Bayan Obo aeschynite minerals are relatively strongly La-depleted and Nd-enriched. The compositional variations in aeschynite-group minerals were controlled by the crystal chemistry and affected by fluid composition.

Original language	English
Pages (from-to)	1207-1214
Number of pages	8
Journal	European Journal of Mineralogy
Volume	13
Issue number	6
Publication status	Published - Nov 2001

Keywords

aeschynite-group
microprobe analysis
compositional variation
bayan obo

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title = "Compositional variation of aeschynite-group minerals in the Bayan Obo Nb-REE-Fe ore deposit, Inner Mongolia, China",

abstract = "The aeschynite-group minerals occurring in an aegirine-fluorite-dolomite-aeschynite vein in the Bayan Obo Nb-REE-Fe deposit show complex compositional zoning in BSE images. Microprobe analyses revealed that the concentrations of REE2O3are globally high in aeschynite-group minerals, ranging from 36.72 to 40.32 wt.\%. Four species were identified in the same sample, these being aeschynite-(Ce), aeschynite-(Nd), nioboaeschynite-(Ce) and nioboaeschynite-(Nd). The correlations among cations suggest two special coupled substitutions with charge-balanced described by the exchange vectors as CaNb(Nd,Sm,Pr)-1Ti-1 and LaNbTh-1Ti-1. The chondrite-normalized REE patterns are hump-shaped with the maximum at Pr or Nd. The chondrite-normalized La/Nd ratios vary in the range \textasciitilde{}0.15 to 0.40. It indicates that at Bayan Obo aeschynite minerals are relatively strongly La-depleted and Nd-enriched. The compositional variations in aeschynite-group minerals were controlled by the crystal chemistry and affected by fluid composition.",

keywords = "aeschynite-group, microprobe analysis, compositional variation, bayan obo",

author = "Z. Yang and Martin Smith and P. Henderson and \{Le Bas\}, M.J. and K. Tao and P. Zhang",

year = "2001",

month = nov,

language = "English",

volume = "13",

pages = "1207--1214",

journal = "European Journal of Mineralogy",

issn = "0935-1221",

number = "6",

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TY - JOUR

T1 - Compositional variation of aeschynite-group minerals in the Bayan Obo Nb-REE-Fe ore deposit, Inner Mongolia, China

AU - Yang, Z.

AU - Smith, Martin

AU - Henderson, P.

AU - Le Bas, M.J.

AU - Tao, K.

AU - Zhang, P.

PY - 2001/11

Y1 - 2001/11

N2 - The aeschynite-group minerals occurring in an aegirine-fluorite-dolomite-aeschynite vein in the Bayan Obo Nb-REE-Fe deposit show complex compositional zoning in BSE images. Microprobe analyses revealed that the concentrations of REE2O3are globally high in aeschynite-group minerals, ranging from 36.72 to 40.32 wt.%. Four species were identified in the same sample, these being aeschynite-(Ce), aeschynite-(Nd), nioboaeschynite-(Ce) and nioboaeschynite-(Nd). The correlations among cations suggest two special coupled substitutions with charge-balanced described by the exchange vectors as CaNb(Nd,Sm,Pr)-1Ti-1 and LaNbTh-1Ti-1. The chondrite-normalized REE patterns are hump-shaped with the maximum at Pr or Nd. The chondrite-normalized La/Nd ratios vary in the range ~0.15 to 0.40. It indicates that at Bayan Obo aeschynite minerals are relatively strongly La-depleted and Nd-enriched. The compositional variations in aeschynite-group minerals were controlled by the crystal chemistry and affected by fluid composition.

AB - The aeschynite-group minerals occurring in an aegirine-fluorite-dolomite-aeschynite vein in the Bayan Obo Nb-REE-Fe deposit show complex compositional zoning in BSE images. Microprobe analyses revealed that the concentrations of REE2O3are globally high in aeschynite-group minerals, ranging from 36.72 to 40.32 wt.%. Four species were identified in the same sample, these being aeschynite-(Ce), aeschynite-(Nd), nioboaeschynite-(Ce) and nioboaeschynite-(Nd). The correlations among cations suggest two special coupled substitutions with charge-balanced described by the exchange vectors as CaNb(Nd,Sm,Pr)-1Ti-1 and LaNbTh-1Ti-1. The chondrite-normalized REE patterns are hump-shaped with the maximum at Pr or Nd. The chondrite-normalized La/Nd ratios vary in the range ~0.15 to 0.40. It indicates that at Bayan Obo aeschynite minerals are relatively strongly La-depleted and Nd-enriched. The compositional variations in aeschynite-group minerals were controlled by the crystal chemistry and affected by fluid composition.

KW - aeschynite-group

KW - microprobe analysis

KW - compositional variation

KW - bayan obo

M3 - Article

SN - 0935-1221

VL - 13

SP - 1207

EP - 1214

JO - European Journal of Mineralogy

JF - European Journal of Mineralogy

IS - 6

ER -

Compositional variation of aeschynite-group minerals in the Bayan Obo Nb-REE-Fe ore deposit, Inner Mongolia, China

Abstract

Keywords

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