ルチルを含む耐火性エコロギット:大陸と枯渇したマントルの間の欠けているリンク
1Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, USA.
まとめ
地球 地球 地球 地球 地球 地球
科学分野:
- 地質化学 地質化学
- ペトロロジー・ペトロロジーとは
- 地球科学 地球科学 地球科学
背景:
- 地球の大陸地殻と枯渇したマントルは,ニオビウム (Nb),タンタール (Ta),チタン (Ti) のような主要な元素の亜コンドリート比を示しています.
- この元素の不均衡は,超コンドリート比率を持つ計上されていない貯蔵庫の存在を示唆しています.
研究 の 目的:
- Nb,Ta,Tiに対する地球の観測された質量不均衡の解決における耐火性エクロジットの役割を調査する.
- これらの元素の不一致を説明できるエコロギットの鉱物学的および塊岩地化学的特性を決定する.
主な方法:
- クラトン石層マントルのクセノリシックエコロギット内の鉱物における微量元素組成の分析.
- エクロジット貯水池の必要な質量と組成を定量化するための地化学モデリング.
主要な成果:
- エクロギットにおけるルチルは,NbとTaの豊富性を著しく制御する.
- エクロジットは,必要な貯蔵庫と一致する超コンドリートNb/Ta,Nb/La,Ti/Zr比を示しています.
- 地球の予算を均衡させるには,特定の元素の濃度と比率を持つ約1-6%のエクロジットが必要である.
結論:
- 耐火性エコロギット,特にルチールに富んだ品種は,地球のNb,Ta,Tiの質量不均衡を解決する欠けている貯蔵庫の有望な候補である.
- 必要なエコロギット質量は,重要な部分が下層マントルに存在し,潜在的にコアマントル境界の近くにあることを示唆しています.
関連する概念動画
The Carbon Cycle
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.
The Sulfur Cycle
Sulfur, an important element in the chemical makeup of proteins, is recycled through the atmosphere and aquatic and terrestrial environments. Found in the atmosphere as sulfur dioxide (SO2), sulfur is released by decaying organisms, weathered rocks, geothermal vents, volcanos, and burning fossil fuels. It is deposited into the ecosystem, cycled through the biotic community, and either released back into the atmosphere as gas or deposited in marine sediment for long-term storage and eventual...
Habitat Fragmentation
Habitat fragmentation describes the division of a more extensive, continuous habitat into smaller, discontinuous areas. Human activities such as land conversion, as well as slower geological processes leading to changes in the physical environment, are the two leading causes of habitat fragmentation. The fragmentation process typically follows the same steps: perforation, dissection, fragmentation, shrinkage, and attrition.
Quarrying of Stone
Quarrying is the process of extracting stone from a quarry, where specialized techniques are employed to remove large blocks of stone safely and efficiently. This process can involve controlled explosions or more precision-oriented methods such as cutting and drilling.
One common method involves using a diamond belt saw to cut large blocks from the quarry face. These blocks can be about 50 feet long and 12 feet high. After the initial vertical cut, drilling is performed at the base of the block.
One common method involves using a diamond belt saw to cut large blocks from the quarry face. These blocks can be about 50 feet long and 12 feet high. After the initial vertical cut, drilling is performed at the base of the block.
Deleterious Substances in Aggregate
Deleterious substances in aggregates can be detrimental to the quality and durability of concrete. These substances include organic impurities like loam, which interfere with cement hydration and are usually present in the sand. These prevent a good bond between aggregate and cement paste. Organic impurities can be detected using the colorimetric test, where the darkness of a solution after agitation indicates the level of organic content.
Another type of impurity is clay and fine material that...
Another type of impurity is clay and fine material that...
Microbial Leaching
Microbial leaching, also known as bioleaching, is an environmentally favorable method for extracting metals from low-grade ores using specific microorganisms. This biotechnological approach is particularly valuable for mining operations targeting copper, gold, and uranium, where traditional extraction methods may be economically or environmentally impractical.Copper Leaching and Microbial CatalysisIn copper bioleaching, crushed ore is arranged into heaps and irrigated with a dilute sulfuric...


