概括
星际尘埃颗粒 (IDP) 将-3送到地球,这可能解释了热点中-3/-4的高比率. 这表明古代沉积物,而不是原始地幔材料,可能是来源.
科学领域:
- 地质化学 地质化学
- 地球科学 地球科学 地球科学
- 行星科学 行星科学
背景情况:
- 热点岩中的高-3/-4比率传统上归因于原始的,未被气化的地球地幔深层水库.
- 星际尘埃颗粒 (IDP) 是传送到地球表面的-3的重要来源.
研究的目的:
- 研究行星间尘埃颗粒 (IDP) 和回收沉积物的作用,以解释在热点中观察到的-3/-4比率.
- 挑战一种原始深层地幔来源高-3/-4比率的主流理论.
主要方法:
- 在热点岩石中分析-3和-4的比率.
- 考虑通过行星间尘埃颗粒 (IDP) 输送-3.
- 模拟古代深海沉积物回收到地球地幔中的模式.
主要成果:
- 含有DP的深海沉积物的回收利用可以解释热点岩石中-3/-4的高比率.
- 具有高-3/-4比率的玄武岩可能起源于古代海底沉积物 (1.5-2.0亿年前) 的脱气.
- IDPs的涌入也解释了地幔样本中观察到的虹和 siderophile 组成.
结论:
- 热点岩中高-3/-4比率的存在很可能是由从IDP中缩的古老沉积物的纳入和脱气解释的.
- 这为原始深层地幔储库理论提供了一个替代性的解释.
- 星际尘埃粒子的涌入在地幔地化学中起着至关重要的作用.
相关概念视频
Noble Gases
The elements in group 18 are noble gases (helium, neon, argon, krypton, xenon, and radon). They earned the name “noble” because they were assumed to be nonreactive since they have filled valence shells. In 1962, Dr. Neil Bartlett at the University of British Columbia proved this assumption to be false.
Nuclear Fusion
The process of converting very light nuclei into heavier nuclei is also accompanied by the conversion of mass into large amounts of energy, a process called fusion. The principal source of energy in the sun is a net fusion reaction in which four hydrogen nuclei fuse and ultimately produce one helium nucleus and two positrons.
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...
Nuclear Binding Energy
The difference between the calculated and experimentally measured masses is known as the mass defect of the atom. In the case of helium-4, the mass defect indicates a “loss” in mass of 4.0331 amu – 4.0026 amu = 0.0305 amu. The loss in mass accompanying the formation of an atom from protons, neutrons, and electrons is due to the conversion of that mass into energy that is evolved as the atom forms. The nuclear binding energy is the energy produced when the atoms’ nucleons are bound together;...
Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
Emission Spectra
When solids, liquids, or condensed gases are heated sufficiently, they radiate some of the excess energy as light. Photons produced in this manner have a range of energies, and thereby produce a continuous spectrum in which an unbroken series of wavelengths is present.


