Mineralization of the Bayan Obo Rare Earth Element Deposit by Recrystallization and Decarbonation

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F41601670%3A_____%2F22%3AN0000006" target="_blank" >RIV/41601670:_____/22:N0000006 - isvavai.cz</a>

Result on the web

<a href="https://pubs.geoscienceworld.org/segweb/economicgeology/article/117/6/1327/612483/Mineralization-of-the-Bayan-Obo-Rare-Earth-Element" target="_blank" >https://pubs.geoscienceworld.org/segweb/economicgeology/article/117/6/1327/612483/Mineralization-of-the-Bayan-Obo-Rare-Earth-Element</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.5382/econgeo.4926" target="_blank" >10.5382/econgeo.4926</a>

Result language

angličtina

Original language name

Mineralization of the Bayan Obo Rare Earth Element Deposit by Recrystallization and Decarbonation

Original language description

The genesis of the Bayan Obo giant rare earth element (REE) deposit has been debated for several decades. Here, we report the isotopic effects of dynamic recrystallization in the H8 carbonatite, which is the principal ore carrier in the deposit. We studied fresh drill core to a depth of 1.78 km and documented the elemental and C-O-Sr isotope evolution of rock-forming dolomite during its deformation and reaction with fluids. The precursor dolomite and the products of its recrystallization differ in δ13CVienna-PeeDee Belemnite (V-PDB) (–1.09 to 2.37 vs. –3.59 to 0.79‰, respectively) and 87Sr/86Sr (0.70241–0.70394 vs. 0.70288–0.71409, respectively), and show a similar δ18Ovienna-standard mean ocean water (V-SMOW) range (10.3–16.9‰). The strong negative shift in δ13CV-PDB indicates that, locally, there was as much as 40% loss of CO2 from the precursor dolomite, although most of the recrystallized dolomite experienced decarbonation on a smaller scale. Clumped monazite grains associated with apatite in paragenetically similar samples yielded variable in situ Th-Pb dates (980–340 Ma), whereas those in monomineralic veinlets give a consistent age of ~400 Ma and consistent initial Nd isotope ratios. This indicates that the wide range of dates may not represent real REE depositional events and that the primary REE minerals deposited in the Mesoproterozoic underwent isotopic reequilibration and REE remobilization in the mid-Paleozoic. Recrystallization and decarbonation of dolomite in the H8 unit were facilitated by its reaction with subduction-derived silica- and halogen-rich fluid, genetically linked to plate-convergence processes along the northern margin of the North China craton, and did not require an influx of REEs from an external source.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10505 - Geology

Project

<a href="/en/project/GX19-29124X" target="_blank" >GX19-29124X: EVOLUTION AND POST-EMPLACEMENT HISTORY OF CARBONATITES: IMPLICATIONS FOR THE MOBILITY AND CONCENTRATION OF CRITICAL METALS</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2022

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Economic Geology

ISSN

0361-0128

e-ISSN

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Volume of the periodical

117

Issue of the periodical within the volume

6

Country of publishing house

US - UNITED STATES

Number of pages

12

Pages from-to

1327-1338

UT code for WoS article

000827078800004

EID of the result in the Scopus database

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