Planetesimal accretion timescales inferred from Hf-W chronometry

从 Hf-W 计时法推断出的星子吸积时标

• 批准号: 211564154
• 负责人: Professor Dr. Thorsten Kleine
• 金额: --
• 依托单位: American Museum of Natural History (AMNH)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/211564154?language=en
• 关键词: Planetesimal; accretion; timescales; inferred; Hf

Determining the timescales of planetary accretion in the inner solar system is critical to understanding planet formation and for constraining the parameters that controlled the subsequent evolution of planets. Short-lived nuclides are well suited for obtaining such age constraints and the 182Hf–182W chronometer has proven particularly useful for providing the timescales of the chemical differentiation of asteroids and terrestrial planets. The major aim of this research project will be to obtain highly precise Hf–W ages for ureilites and enstatite chondrites and to constrain the accretion timescales of their parent bodies. Both ureilites and enstatite chondrites have formed in distinct regions of the solar nebula, where accretion may have been rapid. As such, knowing the accretion timescales of these meteorite parent bodies is essential for understanding planetary accretion in the inner solar system. However, information on the ages of ureilites and enstatite chondrites are scarce and their accretion timescales are not known. The chronological work on ureilites and enstatite chondrites will be complemented by Hf–W dating of Ca-Al-rich inclusions with the aim to better constrain the initial Hf and W isotopic compositions of the solar system. These parameters are critical for a precise determination of Hf–W ages of meteoritic materials but are currently not known sufficiently precise.

确定内太阳系行星吸积的时间尺度对于理解行星的形成和限制控制行星随后演化的参数至关重要。短寿命核素非常适合于获得这种年龄限制，事实证明，182Hf-182W计时器特别有助于提供小行星和类地行星化学分化的时间尺度。这项研究的主要目的将是获得高精度的辉绿岩和顽火辉石球粒陨石的HF-W年龄，并限制它们的母体的增生时间尺度。辉绿岩和顽火辉石球粒陨石都是在太阳星云的不同区域形成的，那里的吸积可能很快。因此，了解这些陨石母体的吸积时间对于理解内太阳系中的行星吸积是至关重要的。然而，关于透辉石和顽火辉石球粒陨石的年龄信息很少，它们的吸积时间也不清楚。对辉绿岩和顽火辉石球粒陨石的年代学工作将得到富Ca-Al包裹体的HF-W测年的补充，目的是更好地约束太阳系的初始Hf和W同位素组成。这些参数对于准确确定陨石材料的HF-W年龄至关重要，但目前还不够精确。