アノートソサイトの熱い,深く沈んだ隕石による変化の際に,短命の酸素拡散
1Department of Geological Sciences, University of Tennessee, Knoxville, TN 37996-1410, USA. Chemical and Analytical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6365, USA.
Science (New York, N.Y.)
|December 22, 1999
まとめ
メタイグニオスの岩石のプラジオクラゼは,極度の酸素-18の枯渇を示し,高温で流星流体との相互作用を示しています. これは,アノースサイト内の急速な液体交換と拡散を示唆しています.
科学分野:
- 地質化学 地質化学
- 同位体地質学とは,同位体地質学である.
- メタモルフ Petrology メタモルフペトロロジー
背景:
- メタイニオスの岩のプラジオクラスは,流体岩相互作用の記録を保存することができます.
- 酸素同位体組成は,地質学的過程についての洞察を提供します.
研究 の 目的:
- ボールズ・ブッテ・アノルトサイトからのプラジオクラゼの酸素同位体組成を調べる.
- アノースサイト内の流体相互作用の性質とタイミングを決定する.
主な方法:
- プラジオクラゼの酸素同位体分析.
- プラジオクラゼ結晶の微細構造分析.
- 同位体交換の地球化学モデリング.
主要な成果:
- プラジオクラゼは,酸素-18値が非常に枯渇している (-16/mlまで).
- 隕石流体との高温 (500°C以上) の同位体交換の証拠.
- 反応により高まった透性により,流体の流入が容易になりました.
- 鋭い同位体グラデーションは,短命 (~10 ^ 4年) の拡散交換と高い水:岩比を示しています.
結論:
- 流星流体により,高温でアノルトサイトが大幅に変化した.
- 急速な液体交換と,その後の拡散の停止が起こった.
- ボールズ・ブッテ・アノルソサイトは,古代の隕石・熱水系へのユニークな窓を提供します.
関連する概念動画
03:06Alkali Metals
Group 1 elements are soft and shiny metallic solids. They are malleable, ductile, and good conductors of heat and electricity. The melting points of the alkali metals are unusually low for metals and decrease going down the group, while the density increases going down the group with the exception of potassium (Table 1).
Table 1: Properties of the alkali metals
Table 1: Properties of the alkali metals
01:27Atomic Spectroscopy: Effects of Temperature
Atomization, converting samples into gas-phase atoms and ions, is essential for atomic spectroscopy. The flame temperature required for atomization affects the efficiency of the atomic spectroscopic methods by increasing the atomization efficiency and the relative population of the excited and ground states.
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature from...
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature from...
01:20Hot Weather Concreting
Concreting at elevated temperatures accelerates the hydration process, leading to quicker setting but potentially reducing the long-term strength of the concrete structure. Additionally, low air humidity fosters rapid moisture loss from the concrete, resulting in reduced workability, pronounced plastic shrinkage, and a higher likelihood of crazing.
Mitigating the heat increase in concrete can be economically achieved by shading aggregate stockpiles to prevent heating from solar radiation,...
Mitigating the heat increase in concrete can be economically achieved by shading aggregate stockpiles to prevent heating from solar radiation,...
01:26Alkali Aggregate Reaction in Concrete
The alkali-aggregate reaction in concrete involves natural siliceous minerals in aggregates reacting with alkaline hydroxides derived from cement alkalis. This reaction forms an alkali-silica gel that absorbs water, swells, and increases in volume, which is confined by the surrounding cement paste, creating internal pressures that crack and disrupt the concrete. The extent of expansion and damage can be partly attributed to the alkali-silica reaction's osmotic hydraulic pressure and the...
01:15Metabolism of Chemolithotrophs
Chemolithotrophs are microorganisms that obtain energy by oxidizing inorganic molecules such as hydrogen gas (H₂), ammonia (NH₃), reduced sulfur compounds (H₂S, S²⁻), and ferrous iron (Fe²⁺). Unlike heterotrophic organisms that rely on organic carbon, chemolithotrophs transfer electrons from these inorganic donors to the electron transport chain (ETC), generating a proton motive force (PMF) that drives ATP synthesis through oxidative phosphorylation. However, because inorganic electron donors...
01:19Acid Mine Drainage
Mining activities that disturb sulfide-rich rocks, particularly those containing pyrite (FeS₂), initiate a cascade of geochemical and microbiological processes with serious environmental implications. When exposed to air and water, pyrite undergoes oxidation, releasing sulfate, ultimately forming sulfuric acid and mobilizing heavy metals into surrounding water systems. This phenomenon, known as acid mine drainage (AMD), results in low pH waters laden with toxic elements that threaten aquatic...