深层地幔的pton揭示了地球早期的碳状物质积聚
Sandrine Péron1, Sujoy Mukhopadhyay2, Mark D Kurz3
1Department of Earth and Planetary Sciences, University of California, Davis, Davis, CA, USA. scperon@ucdavis.edu.
Nature
|December 16, 2021
概括
来自深层地幔羽毛的pton同位素表明,早期地球积累了碳状物质. 这一发现表明,来自多个来源的挥发性和耐火性元素同时增加,可能包括太阳系外的行星体.
科学领域:
- 行星科学 行星科学
- 地质化学 地质化学
- 宇宙化学 宇宙化学
背景情况:
- 了解挥发性物质 (碳,,水) 的起源和运送到地球对于理解可居住行星的发展至关重要.
- 挥发物送到地球的机制仍然是科学辩论的主题.
- 克里普顿同位素为挥发性传递提供了宝贵的见解,原因是不同地外来源的显著同位素变化.
研究的目的:
- 通过使用的同位素来调查挥发性物质向地球传送的来源和时间.
- 为了分析原始地幔羽毛中的石同位素,以规避大气污染.
- 为了限制地球积累和挥发性库存的模型.
主要方法:
- 从加拉帕戈斯群岛和冰岛羽毛的深层地幔样本中分析了整个的同位素套件.
- 测量的同位素组成与已知的地球外储库 (地石) 和地球大气相比较.
- 使用具有,和原始同位素组成的样品.
主要成果:
- 除了86Kr之外,研究的羽毛中的pton同位素组成类似于体和大气pton的混合物.
- 这些发现支持原地球早期的碳状物质积累.
- 与碳化石相比,在深层地幔来源中观察到富含中子86Kr的显著缺陷,这表明核合成异常.
结论:
- 结果挑战了仅依靠水力动力损失和地幔排气来解释地球大气中的贵重气体的模型.
- 观察到的的同位素特征表明,挥发性和耐火性元素的同时增加.
- 这表明地球的挥发性和耐火成分起源于多个来源,可能包括太阳系外的行星体,并指出挥发性元素中的核合成异常.
相关概念视频
The Carbon Cycle
41.0K
Carbon is the basis of all organic matter on Earth, and is recycled through the ecosystem in two primary processes: one in which carbon is exchanged among living organisms, and one in which carbon is cycled over long periods of time through fossilized organic remains, weathering of rocks, and volcanic activity. Human activities, including increased agricultural practices and the burning of fossil fuels, has greatly affected the balance of the natural carbon cycle.
41.0K
Carbon-13 (¹³C) NMR: Overview
6.2K
Carbon-13 is a naturally occurring NMR-active isotope of carbon with a low natural abundance of 1.1%. In contrast, carbon-12 is the most abundant isotope of carbon with zero nuclear spin. Therefore, it is NMR inactive. The gyromagnetic ratio of carbon-13 is smaller than that of protons. As a result, carbon-13 resonance is about 6000 times weaker than proton resonance. For a given magnetic field strength, the resonance frequency of carbon-13 is about one-fourth of the resonance frequency for...
6.2K
Carbon Skeletons
111.3K
Life on Earth is carbon-based, as all macromolecules that make up living organisms contain carbon atoms. All organic compounds have a carbon backbone. Each carbon atom is tetravalent and can bond with four other atoms, making it an extraordinarily flexible component of biological molecules. Because carbon’s valence electrons are stable, it rarely becomes an ion. As the carbon chain increases in length, structural modifications such as ring structures, double bonds, and branching side...
111.3K
Sulfur Assimilation
119
Sulfur is an essential element in biological systems, contributing to synthesizing key biomolecules, including amino acids such as cysteine and methionine, and cofactors such as coenzyme A and biotin. Microorganisms primarily assimilate sulfur as sulfate (SO₄²⁻) from the environment, which must undergo a series of biochemical transformations before it can be incorporated into cellular components. As sulfate is highly oxidized, it must undergo assimilatory sulfate reduction to...
119
The Fossil Record
26.1K
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
26.1K
Schwarzschild Radius and Event Horizon
2.2K
No object with a finite mass can travel faster than the speed of light in a vacuum. This fact has an interesting consequence in the domain of extremely high gravitational fields.
The minimum speed required to launch a projectile from the surface of an object to which it is gravitationally bound so that it eventually escapes the object’s gravitational field is called the escape velocity. The escape velocity is independent of the mass of the object. Merging the idea of escape...
The minimum speed required to launch a projectile from the surface of an object to which it is gravitationally bound so that it eventually escapes the object’s gravitational field is called the escape velocity. The escape velocity is independent of the mass of the object. Merging the idea of escape...
2.2K


