Nodular monazite from placers in the Kular Ridge (Arctic Siberia, Russia) : Composition and age. / Lazareva, E. V.; Zhmodik, S. M.; Prokopiev, A. V. et al.
In: Russian Geology and Geophysics, Vol. 59, No. 10, 01.10.2018, p. 1330-1347.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - Nodular monazite from placers in the Kular Ridge (Arctic Siberia, Russia)
T2 - Composition and age
AU - Lazareva, E. V.
AU - Zhmodik, S. M.
AU - Prokopiev, A. V.
AU - Karmanov, N. S.
AU - Sergeenko, A. I.
PY - 2018/10/1
Y1 - 2018/10/1
N2 - Nodular monazite occurs in metamorphic rocks worldwide and has zonal REE patterns. This paper focuses on the composition of nodular monazite hosted by Permian black shales of the Kular Ridge in the Kular-Nera terrane. This monazite variety (called kularite in the Russian literature) reaches commercial amounts in placers of the area. The contents of Ce, Nd, and La in the analyzed monazite nodules show correlations at Ce/Nd = 14.39La + 0.0919 (in apfu) and Ce/Nd = 0.2318La + 0.1135 (in wt.%) and vary regularly from core to rim. All monazite compositions fall on this trend, but specific grains may plot in its different parts. Thermodynamic calculations indicate that monazite forms via an intermediate precursor (LnPO4·2H2O). The Ce:La:Nd changes in different grains record Eh-pH variations during nucleation and a gradual temperature increase during subsequent growth. The Ce:La:Nd ratio changes partly in grain rims as a result of oxidative dissolution. Judging by the tectonic setting, REE came to the Kular-Nera rocks from the weathered Tomtor Nb-REE deposit, being transported by the Paleo-Khatanga River with monazite nanoparticles bound to the surface of clay minerals.
AB - Nodular monazite occurs in metamorphic rocks worldwide and has zonal REE patterns. This paper focuses on the composition of nodular monazite hosted by Permian black shales of the Kular Ridge in the Kular-Nera terrane. This monazite variety (called kularite in the Russian literature) reaches commercial amounts in placers of the area. The contents of Ce, Nd, and La in the analyzed monazite nodules show correlations at Ce/Nd = 14.39La + 0.0919 (in apfu) and Ce/Nd = 0.2318La + 0.1135 (in wt.%) and vary regularly from core to rim. All monazite compositions fall on this trend, but specific grains may plot in its different parts. Thermodynamic calculations indicate that monazite forms via an intermediate precursor (LnPO4·2H2O). The Ce:La:Nd changes in different grains record Eh-pH variations during nucleation and a gradual temperature increase during subsequent growth. The Ce:La:Nd ratio changes partly in grain rims as a result of oxidative dissolution. Judging by the tectonic setting, REE came to the Kular-Nera rocks from the weathered Tomtor Nb-REE deposit, being transported by the Paleo-Khatanga River with monazite nanoparticles bound to the surface of clay minerals.
KW - Kular Ridge
KW - nodular monazite (kularite)
KW - rare-earth elements
KW - ZIRCON
KW - MINERALS
KW - EH-PH DIAGRAMS
KW - DEPOSIT
KW - U-PB
KW - STREAM SEDIMENTS
KW - GEOCHRONOLOGY
KW - XENOTIME
KW - RARE-EARTH-ELEMENTS
KW - AUTHIGENIC MONAZITE
UR - http://www.scopus.com/inward/record.url?scp=85054927299&partnerID=8YFLogxK
U2 - 10.1016/j.rgg.2018.09.010
DO - 10.1016/j.rgg.2018.09.010
M3 - Article
AN - SCOPUS:85054927299
VL - 59
SP - 1330
EP - 1347
JO - Russian Geology and Geophysics
JF - Russian Geology and Geophysics
SN - 1068-7971
IS - 10
ER -
ID: 17116419