Multiple impact events on the L-chondritic parent body: Insights from SIMS U-Pb dating of Ca-phosphates in the NWA 7251 L-melt breccia | |
Li, Ye1; Hsu, Weibiao1,2 | |
刊名 | METEORITICS & PLANETARY SCIENCE |
2018-05-01 | |
卷号 | 53期号:5页码:1081-1095 |
ISSN号 | 1086-9379 |
DOI | 10.1111/maps.13061 |
英文摘要 | Here we report in situ secondary ionization mass spectrometry Ca-phosphate U-Pb ages for an L-impact melt breccia (NWA 7251), which are integrated with petrological and mineral chemical studies of this meteorite. NWA 7251 is a heavily shocked rock that is composed mainly of the chondrite host, impact melt portion, and melt veins (crosscutting and pervasive type). The host is an L4 chondrite that has been shocked to S4. The impact melt portion has a fine-grained igneous texture, and is composed mainly of olivine, low-Ca pyroxene, high-Ca pyroxene, and albitic glass. The impact melt was generated at pressure of >30-35 GPa and temperature of >1300-1500 degrees C during an impact event. The Ca-phosphate grains in the host were affected by a shock heating event. Most of the Ca-phosphate grains in the melt were neocrystallized, but relatively large grains enclosed by or adjacent to metal veins or melt globules are likely inherited. The U-Pb isotopic systematics of Ca-phosphates in NWA 7251 yield an upper intercept age of 4457 +/- 56 Ma and a lower intercept age of 574 +/- 82 Ma on the normal U-Pb concordia diagram. The age of 4457 +/- 56 Ma is interpreted to be related to an early shocking event rather than the thermal metamorphism of the parent body. The impact melt and veins in NWA 7251 were generated at 574 +/- 82 Ma, resulting from disruption of the L chondrite parent body. |
WOS关键词 | MOON-FORMING IMPACT ; ORDOVICIAN METEORITE SHOWER ; EXTRATERRESTRIAL CHROMITE ; ACCESSORY MINERALS ; RATIO ESTIMATION ; MA DISRUPTION ; APATITE ; METAMORPHISM ; ZIRCON ; AGE |
WOS研究方向 | Geochemistry & Geophysics |
语种 | 英语 |
出版者 | WILEY |
WOS记录号 | WOS:000431665400009 |
内容类型 | 期刊论文 |
源URL | [http://libir.pmo.ac.cn/handle/332002/24080] |
专题 | 中国科学院紫金山天文台 |
通讯作者 | Hsu, Weibiao |
作者单位 | 1.Chinese Acad Sci, Purple Mt Observ, Nanjing, Jiangsu, Peoples R China 2.Macau Univ Sci & Technol, Space Sci Inst, Macau, Peoples R China |
推荐引用方式 GB/T 7714 | Li, Ye,Hsu, Weibiao. Multiple impact events on the L-chondritic parent body: Insights from SIMS U-Pb dating of Ca-phosphates in the NWA 7251 L-melt breccia[J]. METEORITICS & PLANETARY SCIENCE,2018,53(5):1081-1095. |
APA | Li, Ye,&Hsu, Weibiao.(2018).Multiple impact events on the L-chondritic parent body: Insights from SIMS U-Pb dating of Ca-phosphates in the NWA 7251 L-melt breccia.METEORITICS & PLANETARY SCIENCE,53(5),1081-1095. |
MLA | Li, Ye,et al."Multiple impact events on the L-chondritic parent body: Insights from SIMS U-Pb dating of Ca-phosphates in the NWA 7251 L-melt breccia".METEORITICS & PLANETARY SCIENCE 53.5(2018):1081-1095. |
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