関連する実験動画
Updated: Jul 12, 2026

08:14
Atom Probe Tomography Analysis of Exsolved Mineral Phases
Published on: October 25, 2019
アルゴン-40:ハワイのキラウエア火山からの海底枕ベースルトの過剰
まとめ
キラウエア火山からの潜水艦の枕ベースルトは,過剰なアルゴン-40を吸収し,不正確なカリウム-アルゴン年代測定につながります. 水位圧と冷却速度は,これらの火山岩のアルゴン-40レベルに大きな影響を与えます.
科学分野:
- 地質化学 地質化学
- 火山学 火山学とは
- ジオクロノロジー (Geochronology) について
背景:
- 海底玄武岩,特に枕玄武岩は,水中で噴火した火山の産物である.
- カリウム-アルゴン年代測定は,岩の年齢を決定するために広く使用されている方法です.
研究 の 目的:
- 潜水艦の枕ベースタルトに過剰な放射性アルゴン-40の存在と分布を調査する.
- これらの玄武岩における過剰な放射性アルゴン-40含有量に影響を与える要因を決定する.
- ポータシウム-アルゴン年代測定のための海底玄武岩の適性を評価する.
主な方法:
- キラウエア火山からの海底枕ベースルトの分析.
- 枕のサンプル内の様々な深さや位置での放射性アルゴン-40含有量の測定.
- アルゴン-40濃度と水静圧と冷却速度の相関.
主要な成果:
- キラウエア火山からの潜水艦の枕ベースルトは,過剰な放射性アルゴン-40を露出しています.
- アルゴン-40濃度は,ガラスの枕の縁の深さに伴い増加します.
- 枕のサンプルでは,リムから内側にアルゴン-40が2590メートルの深さで減少していることが示されました.
- 過剰な放射性アルゴン-40は,水静圧と冷却速度と直接関係しています.
結論:
- 潜水艦の玄武岩に過剰な放射性アルゴン-40が存在することは,カリウム-アルゴン年代測定の正確性を損なう.
- 水位圧と冷却速度は,アルゴン-40の組み込みを制御する重要な要因です.
- 多くの海底玄武岩は,信頼性の高いカリウム-アルゴン年代測定に適していません.
さらに関連する動画
11:50Metal-silicate Partitioning at High Pressure and Temperature: Experimental Methods and a Protocol to Suppress Highly Siderophile Element Inclusions
Published on: June 13, 2015
06:34Operation of a 25 KWth Calcium Looping Pilot-plant with High Oxygen Concentrations in the Calciner
Published on: October 25, 2017
関連する概念動画
Pozzolans
Pozzolans are siliceous or aluminous materials blended with Portland cement. They interact with the calcium hydroxide produced during the hydration of Portland cement and contribute to improved strength and durability of concrete. The pozzolanic activity, a measure of a pozzolan's effectiveness, is typically assessed using the strength activity index, as defined in ASTM C 618-93, which calculates the ratio of the compressive strength of cement mixtures with and without pozzolan.
Fly ash is a...
Fly ash is a...
Qualitative Analysis
For solutions containing mixtures of different cations, the identity of each cation can be determined by qualitative analysis. This technique involves a series of selective precipitations with different chemical reagents, each reaction producing a characteristic precipitate for a specific group of cations. Metal ions within a group are further separated by varying the pH, heating the mixture to redissolve a precipitate, or adding other reagents to form complex ions.
For instance, group IV...
For instance, group IV...
Flame Photometry: Lab
In a flame photometer, when a solution like potassium chloride is aspirated into the flame, the solvent evaporates, leaving behind dehydrated salt. This salt dissociates into free gaseous atoms in their ground state. Some of these atoms absorb energy from the flame, leading to their excitation. The excited atoms return to the ground state, emitting photons at characteristic wavelengths. Because only electronic transitions are involved, the resulting emission lines are very narrow. The intensity...
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.
Alkali 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...
Alkali 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