在大西洋中部山脊玄武岩中,与同位素的相关性
1Laboratoire de Geochimie et Cosmochimie, Institut de Physique du Globe de Paris (IPGP), 4 place Jussieu, 75252 Paris Cedex 05, France.
概括
中大西洋山脊玻璃中的 (Ar) 和 (Pb) 同位素比率显示了地幔回收. 这些相关性表明,可以跟踪地幔过程,类似于.
科学领域:
- 地质化学 地质化学
- 同位素地球化学 同位素地球化学
- 世界地幔地力学地力学
背景情况:
- 了解地幔的组成和演变对于板块构造学和地球的热史至关重要.
- (Pb) 同位素已成为地幔储库和回收过程的已确定的标记物.
- 其他贵气,如 (Ar),作为地幔标记物的作用是不太了解的.
研究的目的:
- 研究中大西洋山脊 (MAR) 玻璃中 (Ar) 和 (Pb) 同位素之间的关系.
- 确定Ar同位素是否可以作为地幔回收的标记物,类似于Pb同位素.
- 为了确定地球地幔内的来源和混合过程.
主要方法:
- 在来自大西洋中部山脊的玻璃样本上进行了分步加热分析.
- 这些测量包括 (40Ar/36Ar) 和 (206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb) 的同位素比率.
- 对同位素数据进行了相关性分析,并在地幔混合模型的背景下进行了解释.
主要成果:
- 最大40Ar/36Ar值与206Pb/204Pb,207Pb/204Pb和208Pb/204Pb比率有很强的正相关性.
- 这些相关性在整个大西洋中是一致的,排除了浅层污染.
- 数据适应了脱气枯竭的上层地幔和具有高206Pb/204Pb和低40Ar/36Ar比率的回收组件之间的混合超波拉.
结论:
- 观察到的相关性强烈表明,同位素可以有效地追踪地幔回收过程.
- 这意味着地幔中含有一种以明显的同位素特征为特征的回收成分.
- 阿贡,像一样,可以被用作一种强大的地化学追踪器,用于理解地球深层动态.
相关概念视频
Atomic Radii and Effective Nuclear Charge
The elements in groups of the periodic table exhibit similar chemical behavior. This similarity occurs because the members of a group have the same number and distribution of electrons in their valence shells.
Radioactive Decay and Radiometric Dating
Radioactivity is a spontaneous disintegration of an unstable nuclide and is a random process, as all the nuclei in the sample do not decay simultaneously. The number of disintegrations per unit time is called the activity (A), which is directly proportional to the number of nuclei in the sample. The decay constant (λ) is an average probability of decay per nucleus in unit time.
Mass Spectrometry: Isotope Effect
Most elements exist in nature as a mixture of isotopes. The isotopes differ in weight due to their respective number of neutrons. The molecular weight of a molecule is different depending on the specific isotope of its elements involved. As a result, the mass spectrum of the molecule exhibits peaks from the same fragment at multiple positions. The positions of these mass signals depend on the mass differences between isotopes. Furthermore, the intensity of these signals is dependent on the...
Inductively Coupled Plasma-Mass Spectrometry (ICP-MS): Interferences
Inductively coupled plasma–mass spectrometry (ICP–MS) is a highly selective and sensitive technique for accurate elemental analysis. Though the analysis of ICP–MS mass spectra is comparatively straightforward, it is affected by spectroscopic and non-spectroscopic interferences. Spectroscopic interferences arise when the plasma contains ionic species with an m/z value the same as the analyte ion. Spectroscopic interference can be categorized as isobaric, polyatomic ions, and refractory oxide ion...


