| L6型普通球粒陨石茂名的岩石学、地球化学和年代学研究 |
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| 关键词:L6-chondrite Maoming geochronology geochemistry |
| 基金项目:本文由国家重点研发计划(编号: 2022YFF0704905)、上海科技馆陨石微结构与化学研究科研创新平台开放课题、国家自然科学基金(编号: 42241107)和天问三号任务关键技术攻关项目(编号: TW3004)联合资助。 |
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| Petrology, Geochemistry, and Geochronology of the L6 Ordinary Chondrite Maoming Meteorite |
| The Maoming meteorite, an L6 ordinary chondrite from a witnessed fall in 2025, is characterized by fresh preservation, negligible terrestrial weathering (W0), and a low degree of shock metamorphism (C-S2). In this study, the petrography, geochemistry, and phosphate U-Pb chronology of the Maoming meteorite were systematically investigated using scanning electron microscopy, bulk major- and trace-element analyses, and in-situ SHRIMP U-Pb dating. The sample exhibited indistinct chondrule boundaries and extensive silicate recrystallization. Its mineral assemblages, petrographic textures, and major- and trace-element compositions were comparable to those of previously reported L6 ordinary chondrites. The rare earth element pattern was nearly flat, with no significant Eu anomaly. Chlorapatite yields a weighted mean 207Pb/206Pb age of (4 480±12) Ma, which was younger than previously reported ages for weakly shocked L6 ordinary chondrites. Moreover, its U-Pb isotopic system showed no evidence of reset related to the ~470 Ma breakup of the L-chondrite parent body. These results indicate that the Maoming meteorite was derived from the middle to deep interior of the L-chondrite parent body, where it underwent extensive thermal metamorphism followed by slow cooling, without significant melt differentiation. Therefore, it provides a critical end-member constraint on the late-stage cooling history of L6 ordinary chondrites. |
| YUE Cheng,CHE Xiaochao,LONG Tao,WANG Ziyao,WANG Huimin,WANG Chen,LIU Dunyi.2026.Petrology, Geochemistry, and Geochronology of the L6 Ordinary Chondrite Maoming Meteorite[J].Acta Geoscientica Sinica,47(3):555-564. |
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