GEOCHEMISTRY OF RARE-EARTH ELEMENTS IN THERMAL WATERS OF THE UZON-GEYZERNAYA HYDROTHERMAL SYSTEM (Kamchatka)

2018 ◽  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Hydrothermal System ◽  
Thermal Waters

Geochemistry of major and rare earth elements in garnet of the Kal-e Kafi skarn, Anarak Area, Central Iran: Constraints on processes in a hydrothermal system

2016 ◽  
Vol 54 (5) ◽  
pp. 423-438 ◽  
Author(s):  
S. Ranjbar ◽  
S. M. Tabatabaei Manesh ◽  
M. A. Mackizadeh ◽  
S. H. Tabatabaei ◽  
O. V. Parfenova
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Hydrothermal System ◽  
Central Iran

Long-lived Radioactive Elements and REE as Fingerprints of Deep Groundwater Flow

2021 ◽  
Author(s):  
Marina Ćuk Đurović ◽  
Maja Todorović ◽  
Igor Jemcov ◽  
Petar Papić
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Groundwater Flow ◽  
Natural Radioactivity ◽  
Thermal Waters ◽  
Geochemical Behavior ◽  
Deep Circulation ◽  
Regional Groundwater ◽  
Hydrogeological Systems

<p>Groundwater originating from great depths provide a valuable geochemical sampling medium for exploring the development of the Earth's crust, geological, and hydrogeological resources. This particularly applies to sites of natural springs, where favorable hydrogeological conditions enabled regional discharge. Despite the numerous occurrences of mineral and thermal waters in Serbia, the current understanding of the regional groundwater flow is associated with many open questions that need to be addressed. From a geological standpoint, Serbia is part of the Alpine-Mediterranean mountain belt. From the middle of the Mesozoic to the present, this area underwent processes of subduction, collision, and extensions with accompanying voluminous magmatism and volcanism. As a result of the mentioned geodynamic events, the Serbian territory was a zone of intensive tectonomagmatic processes which had a significant impact on the formation of the hydrogeological structures for forming groundwater enriched with specific elements and elevated temperatures.</p><p>Understanding groundwater origin and characterization of a deep circulation is a big challenge since the groundwater pathways and aqueous chemistry are significantly influenced by various factors. To contribute to the characterization of the hydrogeological systems in which the mineral and thermal waters of Serbia are formed, a general hydrochemical study was conducted. During this research 190 of the most significant sources of mineral and thermal waters were sampled, belonging to different geological (geotectonic) units all over Serbia. The applied hydrochemical approach of recognition of deep circulation patterns is based on an analysis of rare earth elements (REE) and natural radioactivity. REE and long-lived radionuclides <sup>40</sup>K, <sup>238</sup>U, <sup>232</sup>Th, <sup>226,228</sup>Ra, gross alpha, and beta radioactivity, have proven to be significant fingerprints of water-rock interaction as well as groundwater flow tracers.</p><p>The integrated approach of the hydrogeochemical analysis and multivariate statistical method, including spatial mapping of obtained results, was an important process for meaningful interpretation of the data set. The applied approach summarized the complex hydrochemical properties on a general level defining specific hydrochemical fingerprints of hydrogeological systems with distinct geochemical characteristics and flow patterns. Geochemical behavior of natural tracers (REE) and radioactivity contributed to further characterization of deep hydrogeological systems in basins structures, hard rocks (igneous and metamorphic rocks), as well as carbonate environments.</p><p>Rare-earth element data (including abundances and fractionation patterns along with anomalies of Ce and Eu and interelement ratios), relationships of U and Th as elements with different geochemical behavior, and the content of Ra in groundwaters have been singled out as important indicators of deep hydrogeological systems. The results showed that the isolated regional hydrogeological systems are in the function of significant tectonic structures/dislocations, but also hydrogeological characteristics and circulation conditions. Further use of the proposed methodology will provide important data from the assessment of the origin of hydro-geofluids in Serbia and contribute to the wider picture in the understanding of the hydrogeological evolution of regional groundwater flow.</p><p><strong>Keywords:</strong> natural radioactivity, rare earth elements, hydrogeochemical fingerprints, regional groundwater flow</p>

scholarly journals Carbonatite-Related REE Deposits: An Overview

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 965
Author(s):  
Zhen-Yu Wang ◽  
Hong-Rui Fan ◽  
Lingli Zhou ◽  
Kui-Feng Yang ◽  
Hai-Dong She
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Fractional Crystallization ◽  
Hydrothermal System ◽  
Experimental Petrology ◽  
Evolution Process ◽  
Primitive Mantle ◽  
Carbonate Minerals ◽  
Critical Metals ◽  
Carbonatite Magma

The rare earth elements (REEs) have unique and diverse properties that make them function as an “industrial vitamin” and thus, many countries consider them as strategically important resources. China, responsible for more than 60% of the world’s REE production, is one of the REE-rich countries in the world. Most REE (especially light rare earth elements (LREE)) deposits are closely related to carbonatite in China. Such a type of deposit may also contain appreciable amounts of industrially critical metals, such as Nb, Th and Sc. According to the genesis, the carbonatite-related REE deposits can be divided into three types: primary magmatic type, hydrothermal type and carbonatite weathering-crust type. This paper provides an overview of the carbonatite-related endogenetic REE deposits, i.e., primary magmatic type and hydrothermal type. The carbonatite-related endogenetic REE deposits are mainly distributed in continental margin depression or rift belts, e.g., Bayan Obo REE-Nb-Fe deposit, and orogenic belts on the margin of craton such as the Miaoya Nb-REE deposit. The genesis of carbonatite-related endogenetic REE deposits is still debated. It is generally believed that the carbonatite magma is originated from the low-degree partial melting of the mantle. During the evolution process, the carbonatite rocks or dykes rich in REE were formed through the immiscibility of carbonate-silicate magma and fractional crystallization of carbonate minerals from carbonatite magma. The ore-forming elements are mainly sourced from primitive mantle, with possible contribution of crustal materials that carry a large amount of REE. In the magmatic-hydrothermal system, REEs migrate in the form of complexes, and precipitate corresponding to changes of temperature, pressure, pH and composition of the fluids. A simple magmatic evolution process cannot ensure massive enrichment of REE to economic values. Fractional crystallization of carbonate minerals and immiscibility of melts and hydrothermal fluids in the hydrothermal evolution stage play an important role in upgrading the REE mineralization. Future work of experimental petrology will be fundamental to understand the partitioning behaviors of REE in magmatic-hydrothermal system through simulation of the metallogenic geological environment. Applying “comparative metallogeny” methods to investigate both REE fertile and barren carbonatites will enhance the understanding of factors controlling the fertility.

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