Mineralogy, age and genesis of apatite-dolomite ores at the Seligdar apatite deposit (Central Aldan, Russia)

Fenites associated with carbonatite complexes: A review

“…Harlov et al (2002) indicates that Cl-rich and F-rich fluids could have responsible for the depletion of Y, REE, Na and Si from apatites at Kiirunavaara, Sweden, and Broom-Fendley et al (2016) observed a similar LREE depletion in apatites from the Kangankunde carbonatite. Dolomitic melts at the Seligdar complex, Russia, evolved brines containing 38-42 wt% NaCl-eq which likely removed LREE and Th from apatites, and redistributed these elements into monazite-(Ce) and xenotime-(Y) (Prokopyev et al, 2017). Calcite carbonatite ring dykes on Chilwa Island were depleted in HREE relative to high grade fenites and breccias which have higher HREE:LREE ratios.…”

Geochemistry of Monazite within Carbonatite Related REE Deposits

“…In thin sections, monazite appears in a variety of colors, from colorless to yellowish, greenish, and brownish [9,10] (e.g., Figure 2c,d). More commonly, it is the product of metasomatic/hydrothermal alteration of the primary mineral assemblage within the carbonatite (e.g., apatite) or occurs along the fractures of the matrix carbonate as interstitial fillings or form veinlets or, which appears as fine-grained polycrystalline clusters (e.g., Figure 2e,f, or Figure 3) [11]. The secondary monazite commonly shares mineral associations with apatite, barite, fluorite, hematite, quartz, sulfide, bastnasite, xenotime, feldspar, titanite, synchysite, goyazite, and strontianite.…”

“…[21]; (b) disseminated monazite within dolomite marble from Bayan Obo, Inner Mongolia, China; (c) yellow monazite crystals crystallized on the rim of albite matrix from Evate, Mozambique [9]; (d) green monazite occurs as disseminations in the strontianite matrix in Kangankunde, Malawi [10]; (e) BSE image of anhedral monazite in carbonatite from Mountain Pass, the United States [21]; (f) monazite in strongly foliated dolomite carbonatite with quartz laminae from the Cummins Range carbonatite, Australia [22]; (g) monazite net of veinlets in dolomite from Seligdar apatite deposit, Russia [11]; (h) backscattered electron image showing a vug in dolomite filled with potassium feldspar and monazite from the Wideeda carbonatite, Canada [12]; (i) monazite aggregates together with molybdenite in the calcite carbonatite from Huanglongpu, China; (j) euhedral monazite core with small monazite grains in the cracked and resorbed rim from the Hongcheon complex, Korea [14]; (k,l) typical monazite-pyrochlore-crandallite ore in the Tomtor deposit (Russia); and relict pyrochlore crystal in monazite and goyazite as colloform globular segregations in a colloform goethite aggregate [23]. Ab = albite; Ank = ankerite; Ap = apatite; Mnz = monazite; Dol = dolomite; [21]; (b) disseminated monazite within dolomite marble from Bayan Obo, Inner Mongolia, China; (c) yellow monazite crystals crystallized on the rim of albite matrix from Evate, Mozambique [9]; (d) green monazite occurs as disseminations in the strontianite matrix in Kangankunde, Malawi [10]; (e) BSE image of anhedral monazite in carbonatite from Mountain Pass, the United States [21]; (f) monazite in strongly foliated dolomite carbonatite with quartz laminae from the Cummins Range carbonatite, Australia [22]; (g) monazite net of veinlets in dolomite from Seligdar apatite deposit, Russia [11]; (h) backscattered electron image showing a vug in dolomite filled with potassium feldspar and monazite from the Wideeda carbonatite, Canada [12]; (i) monazite aggregates together with molybdenite in the calcite carbonatite from Huanglongpu, China; (j) euhedral monazite core with small monazite grains in the cracked and resorbed rim from the Hongcheon complex, Korea [14]; (k,l) typical monazite-pyrochlore-crandallite ore in the Tomtor deposit (Russia); and relict pyrochlore crystal in monazite and goyazite as colloform globular segregations in a colloform goethite aggregate [23]. Ab = albite; Ank = ankerite; Ap = apatite; Mnz = monazite; Dol = dolomite; Goe = Goethite; Goy = goyazite; Kfs = K-feldspar; Mo = Molybdenite; Py = pyrite; Pych = pyrochlore; and Qz = Quartz.…”

“…Ab = albite; Ank = ankerite; Ap = apatite; Mnz = monazite; Dol = dolomite; Goe = Goethite; Goy = goyazite; Kfs = K-feldspar; Mo = Molybdenite; Py = pyrite; Pych = pyrochlore; and Qz = Quartz. [15]; (b) monazite on the edge or included within the heterogeneous apatite in the apatite-dolomite ore from the Seligdar deposit, Russia [11]; (c) monazite inclusions within apatite in association with bastnaesite inclusions from the Naantali carbonatite, Finland [16]; (d) apatite crystal with a LREE-rich rim partly replaced and overgrown by monazite associated with LREE-poor carbonate-apatite in the Matongo carbonatite, Burundi [22]; (e) monazite grains girdling around coarse apatite in the Purulia phoscorite, India [17]; and (f) monazite overgrowth on apatite in the Abyan carbonatite, Yemen Republic [18]. Ap = apatite; Bas = bastnasite; and Mnz = monazite.…”

“…In the Catalao I carbonatite complex, weathered monazite displayed a less steep REE pattern (i.e., lower La/Nd ratio) when compared to those within carbonatite [28]. The detailed chemical compositions of monazite within carbonatite related environments can be found in Supplementary Materials Table S2 [ [11][12][13][14][16][17][18]20,23,24,29,30,34,35,[37][38][39][40][41][42][43].…”