The oxygen isotope composition of earth's oldest rocks and evidence of a terrestrial magma ocean
The oxygen isotope composition of earth's oldest rocks and evidence of a terrestrial magma ocean
复制标题
DOI：
10.1002/ggge.20128
复制
发表时间：
2013-06
期刊：
影响因子：
3.7
通讯作者：
D. Rumble;S. Bowring;T. Iizuka;T. Komiya;A. Lepland;M. Rosing;Y. Ueno
中科院分区：
文献类型：
--
作者：
D. Rumble;S. Bowring;T. Iizuka;T. Komiya;A. Lepland;M. Rosing;Y. Ueno
对冥古宙和太古宙岩石的16 O-17 O-18 O同位素分析表明，地球上氧同位素的质量分馏线至少在过去4.0 Ga，甚至可能长达4.2 Ga都具有相同的斜率和截距。氧同位素的均匀化需要产生这种长寿命的一致性，最容易通过在陆地岩浆海洋中混合来建立。测得的地球和月球相同的氧同位素质量分馏线表明，在巨大的月球形成撞击期间，两个天体的氧同位素库同时均匀化。但也不能排除其他导致全球熔融的热源，例如原地球早期吸积过程中的火流星撞击、短寿命放射性同位素的衰变或地核与地幔分离过程中释放的能量。
Analysis of Hadean and Archean rocks for 16O‐17O‐18O isotopes demonstrates that the Terrestrial Mass Fractionation Line of oxygen isotopes has had the same slope and intercept for at least the past 4.0 and probably for as long as 4.2 Ga. The homogenization of oxygen isotopes required to produce such long‐lived consistency was most easily established by mixing in a terrestrial magma ocean. The measured identical oxygen isotope mass fractionation lines for Earth and Moon suggest that oxygen isotope reservoirs of both bodies were homogenized at the same time during a giant moon‐forming impact. But other sources of heat for global melting cannot be excluded such as bolide impacts during early accretion of proto‐Earth, the decay of short‐lived radioactive isotopes, or the energy released during segregation of core from mantle.