Planetesimal accretion timescales inferred from Hf-W chronometry

确定内太阳系行星吸积的时间尺度对于理解行星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，182 Hf-182 W精密时计已被证明特别有助于提供小行星和类地行星化学差异的时间尺度。本研究计划的主要目的是获得高精度的辉橄榄岩和顽火辉石年龄，并限制其母体的增生时间尺度。在太阳星云的不同区域都形成了辉绿岩和顽火辉石，那里的吸积可能非常迅速。因此，了解这些陨石母体的吸积时间尺度对于了解内太阳系的行星吸积至关重要。然而，关于钠长石和顽火辉石年龄的信息很少，它们的增生时间尺度也不清楚。对钠辉橄榄岩和顽火辉石的年代学研究将通过富钙铝包裹体的Hf-W定年来补充，目的是更好地限制太阳系的初始Hf和W同位素组成。这些参数对于精确测定陨石材料的Hf-W年龄至关重要，但目前还不知道足够精确。

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.