The source of Fengjia and Langxi barite–fluorite deposits in southeastern Sichuan, China: evidence from rare earth elements and S, Sr, and Sm–Nd isotopic data

Abstract

The barite-fluorite metallogenic belt in southeastern Sichuan is one of the most important barite-fluorite ore-concentrated areas in China. In order to find the ore-forming source and the mineralization age of the Fengjia and Langxi barite-fluorite deposit, we systematically evaluated the rare earth element (REE) contents and isotopic characteristics of S, Sr, and Sm-Nd. The results show that the δ34S values of barites and pyrites are high and similar to S isotopic values of gypsum in the Cambrian Qingxudong Formation (∈ 1 q), suggesting that the sulphur source was from Cambrian evaporite strata. The initial 87 Sr/ 86 Sr ratios of fluorites and barites range from 0.708800 to 0.712999, and these values are similar to Cambrian carbonate rocks and Lower Ordovician limestone. Except for black shales of the Lower Cambrian Niutitang Formation, the Ba content of other strata was generally low. The REE characteristics of barite and fluorite have close relationships, in regard to the source of ore-forming materials, to the Lower Cambrian Niutitang Formation black shales. Hence, we have concluded that the Cambrian carbonate rocks and Lower Ordovician limestone provide the source of calcium for mineralization and that the source of barium comes from the Lower Cambrian Niutitang Formation black shales. The fluorine contents of the Upper Sinian Doushantuo Formation and the Lower Cambrian Mingxinshi Formation are much higher than other strata, and these formations could provide the source for fluorine. The Sm-Nd isochron age of fluorites is 104 ± 11 Ma, which demonstrates that the mineralization mainly occurred during the late Yanshanian.

Formation timing and genesis of Madiu fluorite deposit in East Qinling, China: Constraints from fluid inclusion, geochemistry, and H–O–Sr–Nd isotopes

“…Separation and purification of Rb and Sr were carried out with the conventional cation‐exchange resin (AG50W‐X12, 200–400 mesh size). Detailed analytical procedures were described in Zou et al (). 87 Sr/ 86 Sr values were internally corrected for mass fractionation using a constant value of 88 Sr/ 86 Sr = 8.375209 by exponential law.…”

“…The fluorite Sm–Nd isotopic analyses were performed at the Isotope Laboratory (Tianjin Center) of the China Geological Survey, using a Thermo Fisher Scientific Triton TIMS. Detailed analytical procedures were described in Zou et al (). The measured 146 Nd/ 144 Nd ratios were corrected with 146 Nd/ 144 Nd = 0.7219 by exponential law.…”

“…Due to the similar elemental behaviours between Sr and Ca, Sr isotopes can be used to determine the source of Ca (Deng et al, 2015;Ruiz, Kesler, & Jones, 1985;Ruiz, Kesler, Jones, & Sutter, 1980;Sato et al, 2003). Furthermore, fluorite Sm-Nd dating is an effective and reliable technique to directly date hydrothermal fluorite mineralization (Chesley, Halliday, & Scrivener, 1991;Munoz, Premo, & Courjault-Radé, 2005;Pei et al, 2017;Smolyanskii & Bogomolov, 2011;Zou, Fang, Zhang, & Zhang, 2017). In this paper, we conducted systematic analyses on the Fls, REE, H-O-Sr isotopes, and Sm-Nd geochronology of the Madiu deposit to constrain the mineralization age and the source of ore-forming fluids and materials.…”

The role of the structures on the fluorite mineralization: Insight to fluid inclusion and alteration map of the Laal-kan fluorite deposit, NW Iran

“…The location of the studied regions is shown by the black rectangle and some fluorite indices distribution by the yellow pin. deposited from (Alipour et al, 2015;Parsa et al, 2016;Zou et al, 2016;Ehya and Mazraei, 2017;Zou et al, 2017), thus the veins can provide valuable data about the geological history of the deformed crust. The structure of veins can be used for distinguishing the relative age of the deformation phase as well (Behyari and Shahbazi, 2019).…”

New evidence from the Wuliji'Oboo fluorite deposit for the role of the paleo‐Pacific Plate and Mongol–Okhotsk suture in creating extensive fluorite mineralization in the Great Xing'an Range, NE China

“…Fluorite is the most important natural raw material in the fluorine chemical industry, noticeably receiving attention by many researchers (Bühn, Rankin, Schneider, & Dulski, 2002;Gigoux et al, 2015;Graupner et al, 2015;Munoz, Premo, & Courjault-Radé, 2005;Pei et al, 2017;Ruiz, Kesler, & Jones, 1985;Ruiz, Kesler, Jones, & Sutter, 1980;Zemri et al, 2015;Zou, Fang, Zhang, & Zhang, 2017). The production of China's fluorite ranks first in the world and the reserves are the third in the world (Ober, 2018).…”