In situ U-Pb Dating of Calcite from the South China Antimony Metallogenic Belt

Abstract

Summary Accurately determining the age of hydrothermal ore deposits is difficult, because of lack of suitable mineral chronometers and techniques. Here we present the first LA-MC-ICPMS U-Pb age of carbonates from hydrothermal Sb deposits. Three stages of hydrothermal carbonates from the giant South China Sb metallogenic belt were identified: (1) pre-ore dolomite (Dol-I), (2) syn-ore calcite (Cal-II), and (3) post-ore calcite (Cal-III). The U and Pb isotopic data show that Cal-II yielded a lower intercept age of 115.3 ± 1.5 Ma (MSWD = 2.0), suggesting a Sb mineralization that corresponds to an extension event occurred during the early Cretaceous in South China. Although Cal-III yielded an age of 60.0 ± 0.9 Ma (MSWD = 1.5), indicating a potential tectonothermal event occurred in this belt during the early Cenozoic. Hence, in situ U-Pb dating of calcite offers a new way to determine the age of hydrothermal ore deposits.

In Situ U-Pb Geochronology of Calcite from the World’s Largest Antimony Deposit at Xikuangshan, Southern China

“…The Xiangzhong metallogenic province mainly includes the Xikuangshan Sb deposit, Zhazixi Sb-W deposit, Woxi Sb-Au-W deposit, and Banxi Sb deposit, which is the northwest section of the South China antimony metallogenic belt [10,23]. To present, abundant Sb-(Au-W) deposits have been discovered in this region, with more than 170 Sb-(Au-W) ore deposits and prospects [21,22].…”

“…The laser timing was set with 2 s surface cleaning, 7 s washout, 15 s background, 20 s of ablation, and 6 s washout. The experimental setup and methods are described elsewhere in detail [10,14,16].…”

“…Additionally, Jin et al [9] performed electron spin resonance (ESR) age determination on syn-stibnite quartz samples from quartz-stibnite veins and revealed that Sb mineralization ranged from 66.4 to 51.6 Ma. Moreover, Luo et al [10] proposed an LA-MC-ICP-MS calcite U-Pb age of 60.0 ± 0.9 Ma in the Weizhai Sb deposit, suggesting that a potential tectonothermal event occurred in the South China antimony metallogenic belt during Paleogene. It is noteworthy that a small amount of Sb mineralization was also found in the red sandstone of the upper Daijiaping Formation of the Upper Cretaceous [9].…”

“…1 ppb Pb) and high spatial resolution (ca. 100 µm) [11][12][13][14][15][16][17], and successfully applied to geochronological studies in an increasing number of cases [10,[18][19][20], showing great potential.…”

LA–ICP–MS U–Pb Dating, Elemental Mapping and In Situ Trace Element Analyses of Cassiterites from the Gejiu Tin Polymetallic Deposit, SW China: Constraints on the Timing of Mineralization and Precipitation Environment

“…A working standard (cassiterite AY-4, collected from the Anyuan tin deposit of the Furong district, South China, which has been well calibrated using ID-TIMS with a U-Pb age of 158.2 ± 0.4 Ma, 14) was used to correct the 206 Pb/ 238 U ratio. Operating conditions and analytical procedures were similar to those described by Nuriel et al [36], Luo et al [37], and Yang et al [38]. Tera-Wasserburg concordia diagrams were processed using Isoplot 3.0 [39].…”