Age and Geochemistry of Zircon Megacrysts from Alluvial Deposits in the Huadian Area, Northeastern China
Megacrystic zircons have recently been found in alluvial deposits in the Huadian area of northeastern China. However, studies have rarely been conducted on these zircons. In this article, we present systematic in situ trace element, U-Pb age and Hf isotope data regarding these Huadian zircons, with...
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MDPI AG
2023-06-01
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| author | Haiqi Sun Shaokui Pan Hongyu Qin Yimiao Liu Xiaolong Wu |
| author_facet | Haiqi Sun Shaokui Pan Hongyu Qin Yimiao Liu Xiaolong Wu |
| author_sort | Haiqi Sun |
| collection | DOAJ |
| description | Megacrystic zircons have recently been found in alluvial deposits in the Huadian area of northeastern China. However, studies have rarely been conducted on these zircons. In this article, we present systematic in situ trace element, U-Pb age and Hf isotope data regarding these Huadian zircons, with the aim of investigating their source characteristics and provenance. The studied zircons, with a diameter of 0.7–1.2 cm, are dominantly irregular in shape and have a rounded termination, with a color ranging from near-colorless to reddish brown to maroon. The zircons show oscillatory zoning in CL images, with a Th/U value of 0.18–1.27, which is consistent with the typical features of magmatic zircons. The positive ε<sub>Hf</sub>(t) value of Huadian zircons (4.8–9.2) further indicates the presence of precipitation from the mantle-derived melt, with limited contamination of the crustal components. The obtained weighted mean <sup>206</sup>Pb/<sup>238</sup>U age for these zircons is 17.9 ± 0.12 Ma, which is slightly older than the eruptional ages of the associated alkali basalts (from 17.6 ± 1.09 Ma to 17.8 ± 0.69 Ma), implying a short residence time in the mantle before entrainment. Huadian zircons incorporate a wide range of trace elements, including ΣREE (117–2790 ppm), Hf (4902–11856 ppm) and Y (145–3645 ppm) contents, generating mixed-source protolith assignments. As is suggested by the moderate variations seen in the Hf isotopes, we propose that the source melts of Huadian zircons are complex in nature, which is likely the result of the chemical heterogeneity of the upper mantle. |
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| language | English |
| last_indexed | 2024-03-11T00:47:57Z |
| publishDate | 2023-06-01 |
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| spelling | doaj.art-74f338e0275643b59b4b8014949853cb2023-11-18T20:38:19ZengMDPI AGMinerals2075-163X2023-06-0113788210.3390/min13070882Age and Geochemistry of Zircon Megacrysts from Alluvial Deposits in the Huadian Area, Northeastern ChinaHaiqi Sun0Shaokui Pan1Hongyu Qin2Yimiao Liu3Xiaolong Wu4Gemological Institute, China University of Geosciences, Wuhan 430074, ChinaGemological Institute, China University of Geosciences, Wuhan 430074, ChinaSchool of Prospecting and Surveying Engineering, Changchun Institute of Technology, Changchun 130012, ChinaGemological Institute, China University of Geosciences, Wuhan 430074, ChinaGemological Institute, China University of Geosciences, Wuhan 430074, ChinaMegacrystic zircons have recently been found in alluvial deposits in the Huadian area of northeastern China. However, studies have rarely been conducted on these zircons. In this article, we present systematic in situ trace element, U-Pb age and Hf isotope data regarding these Huadian zircons, with the aim of investigating their source characteristics and provenance. The studied zircons, with a diameter of 0.7–1.2 cm, are dominantly irregular in shape and have a rounded termination, with a color ranging from near-colorless to reddish brown to maroon. The zircons show oscillatory zoning in CL images, with a Th/U value of 0.18–1.27, which is consistent with the typical features of magmatic zircons. The positive ε<sub>Hf</sub>(t) value of Huadian zircons (4.8–9.2) further indicates the presence of precipitation from the mantle-derived melt, with limited contamination of the crustal components. The obtained weighted mean <sup>206</sup>Pb/<sup>238</sup>U age for these zircons is 17.9 ± 0.12 Ma, which is slightly older than the eruptional ages of the associated alkali basalts (from 17.6 ± 1.09 Ma to 17.8 ± 0.69 Ma), implying a short residence time in the mantle before entrainment. Huadian zircons incorporate a wide range of trace elements, including ΣREE (117–2790 ppm), Hf (4902–11856 ppm) and Y (145–3645 ppm) contents, generating mixed-source protolith assignments. As is suggested by the moderate variations seen in the Hf isotopes, we propose that the source melts of Huadian zircons are complex in nature, which is likely the result of the chemical heterogeneity of the upper mantle.https://www.mdpi.com/2075-163X/13/7/882zircon megacrystsHuadianU-Pb ageHf isotopetrace element composition |
| spellingShingle | Haiqi Sun Shaokui Pan Hongyu Qin Yimiao Liu Xiaolong Wu Age and Geochemistry of Zircon Megacrysts from Alluvial Deposits in the Huadian Area, Northeastern China Minerals zircon megacrysts Huadian U-Pb age Hf isotope trace element composition |
| title | Age and Geochemistry of Zircon Megacrysts from Alluvial Deposits in the Huadian Area, Northeastern China |
| title_full | Age and Geochemistry of Zircon Megacrysts from Alluvial Deposits in the Huadian Area, Northeastern China |
| title_fullStr | Age and Geochemistry of Zircon Megacrysts from Alluvial Deposits in the Huadian Area, Northeastern China |
| title_full_unstemmed | Age and Geochemistry of Zircon Megacrysts from Alluvial Deposits in the Huadian Area, Northeastern China |
| title_short | Age and Geochemistry of Zircon Megacrysts from Alluvial Deposits in the Huadian Area, Northeastern China |
| title_sort | age and geochemistry of zircon megacrysts from alluvial deposits in the huadian area northeastern china |
| topic | zircon megacrysts Huadian U-Pb age Hf isotope trace element composition |
| url | https://www.mdpi.com/2075-163X/13/7/882 |
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