海底の玄武岩の微量元素分布のグローバルパターン
Hugh St C O'Neill1, Frances E Jenner
1Research School of Earth Sciences, Australian National University, Canberra, Australian Capital Territory 0200, Australia. hugh.oneill@anu.edu.au
Nature
|November 30, 2012
まとめ
海底の玄武岩化学は,マントルの組成と熱的構造を明らかにする. グローバルな微量元素のパターンは,マグマが室を通して循環し,単に分数結晶化ではなく,玄武岩の化学に影響を及ぼすことを示しています.
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
- プレート・テクトニクス (プレート・テクトニクス)
背景:
- 海洋の地殻は,マントルの上流と部分的な融解によって構成板の縁に形成されます.
- 海底の玄武岩は,マントルの異質性と熱的構造を研究するための重要な製品です.
- 分割結晶化は,噴火前のマグマを改変するプロセスであると考えられている.
研究 の 目的:
- 海洋底の玄武岩の世界の微量元素パターンを調査するために.
- 分割結晶化だけで観察された化学的変化を説明できるかどうかを判断する.
- マグマの組成の変化に起因するプロセスを特定する.
主な方法:
- 海底玄武岩における微量元素のグローバル分布の分析.
- 観察されたパターンと,分数結晶化モデルの予測を比較する.
- 地殻のマグマ室を通るマグマサイクルのモデリング.
主要な成果:
- ベースルトの世界の微量元素分布は,体系的なパターンを示しています.
- このパターンは,分数結晶化だけでは説明できない.
- 地球規模のマグマ室を巡るマグマの循環が主な原因である.
結論:
- 海底の玄武岩の化学は,地殻室を通るマグマの循環によって大きく影響を受けます.
- マグマの流れ,チャンバーの深さ,および親マグマの組成の変動は,グローバルなパターンからの偏差を引き起こす.
- マグマ室のプロセスを理解することは,玄武岩からマントルの組成を解釈するために不可欠です.
関連する概念動画
01:27Diversity of Protists III
Rhizaria are a diverse group of unicellular protists characterized by their threadlike cytoplasmic extensions known as pseudopodia. These structures aid in both locomotion and feeding, giving Rhizaria an amoeboid appearance. Their amoeboid morphology once led to taxonomic confusion, but molecular phylogenetics has clarified their evolutionary placement and emphasized their shared use of pseudopodia despite divergent lineages.This clade comprises diverse lineages such as Chlorarachniophyta,...
01:18Deep Sea Microbial Ecology
The deep ocean and its underlying sediments represent vast, largely unexplored microbial habitats that extend far beyond the sunlit photic zone. The photic (euphotic) zone typically spans the upper ~100–200 meters of pelagic waters in the open ocean, but its depth varies geographically and seasonally, where sufficient light supports photosynthetic life. Below this lies the deep sea, spanning roughly 1000–6000 meters (bathypelagic to abyssal zones), with deeper hadal trenches extending beyond...
01:25Microbial Mats
Microbial communities forming biofilms and mats represent complex, spatially structured ecosystems where metabolic processes are stratified according to light, oxygen, and nutrient gradients. Biofilms are initial colonization stages, only a few millimeters thick, while mature microbial mats can reach centimeter-scale thickness and display intricate vertical organization. Their structural and functional heterogeneity allows microorganisms to occupy distinct ecological niches within a few...
02:06Conditions 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.
01:24Microbes and Other Elemental Cycles
Microbial activity plays a pivotal role in the biogeochemical cycling of iron and manganese, especially at the redox gradients characteristic of stratified aquatic environments. These cycles are driven by microbial transformations between oxidized and reduced forms of the metals, allowing organisms to exploit them for metabolic energy and structural purposes.Iron Cycling Across Redox GradientsIn neutral, oxygen-rich surface waters, iron is predominantly found in its oxidized, insoluble ferric...
00:49Gravimetry: Inorganic And Organic Precipitating Agents
In gravimetry, the precipitant is chosen carefully to obtain a pure solid that can be easily filtered. Common inorganic precipitants can be used to determine several cations and anions. In some cases, the formation of the same precipitate can be used to determine the cation and the anion. For example, the reaction of barium and chromate ions to give barium chromate is used to determine both barium and chromate. However, precipitates such as hydroxides, oxalates, and metal ammonium phosphates...