ダイヤモンドの起源,地震構造,カアプヴァール・ジンバブエ・クラトンの進化

Steven B Shirey¹, Jeffrey W Harris, Stephen H Richardson

¹Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015, USA. shirey@dtm.ciw.edu

Science (New York, N.Y.)

|September 7, 2002

まとめ

カアプヴァール・ジンバブエ・クラトンにおける地震P波の速度変動

科学分野:

地質物理学地質物理学とは地質物理学です.
地質化学地質化学
ミネラロジーは,鉱物学です.

背景:

カップヴァール・ジンバブエ・クレートンの石層マントルは,地球の初期の歴史への手がかりを保持しています.
マントルの組成を理解することは,クラトンの進化とダイヤモンドの形成を解読する上で極めて重要です.

研究の目的:

Kaapvaal-Zimbabweクレートンの石層マントルとダイヤモンドの組成における地震P波の速度との関係を調査する.
クラトンとそのダイヤモンド集団を形作る石油生成過程と地質学的な出来事を再構築する.

主な方法:

ダイヤモンドの安定性フィールド内の様々な深さでの地震P波速度データの分析.
地震データとダイヤモンドの組成と,そのシンゲネティック含有物との相関.

主要な成果:

地震速度の変動は,異なるダイヤモンドタイプ (ハルツブルギット型,エコロギット型,ヘルゾリート型) とその含有物と相関しています.
中期アーケイア時代のマントルの枯渇現象は,ハルツブルギト型ダイヤモンドの形成につながった.
後期アーケイア期の蓄積現象により,エコロギット型ダイヤモンドが誕生した.
プロテロゾイク期はさらにヘルゾロイク期とエコロジク期のダイヤモンドを追加した.

結論:

カップヴァール・ジンバブエ・クラトンの石層マントルは,枯渇,蓄積,変化の複雑な歴史を持っています.
ダイヤモンドの組成は地質学的な時間におけるマントルプロセスとクラトンの進化の強力なトレーサーとして機能します.

さらに関連する動画

13:08

A Salt-Templated Synthesis Method for Porous Platinum-based Macrobeams and Macrotubes

Published on: May 18, 2020

07:59

Coral Reef Arks: An In Situ Mesocosm and Toolkit for Assembling Reef Communities

Published on: January 6, 2023

関連する概念動画

01:54

Convergent Evolution

Evolution shapes the features of organisms over time, ensuring that they are suited for the environments in which they live. Sometimes, selection pressure leads to the rise of similar but unrelated adaptations in organisms with no recent common ancestors, a process known as convergent evolution.The structures that arise from convergent evolution are called analogous structures. They are similar in function even if they are dissimilar in structure. Further, structures can be analogous while also...

02:32

Bonding in Metals

Metallic bonds are formed between two metal atoms. A simplified model to describe metallic bonding has been developed by Paul Drüde called the “Electron Sea Model”.

02:37

Metallic Solids

Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...

01:17

Atomic Structure

The Greek philosopher Democritus proposed that everything on Earth is made up of tiny particles called atomos, Greek for "indivisible," from which the modern term "atom" is derived. In the 19th century, John Dalton proposed the atomic theory that is still largely correct today. He put forth five postulates to explain how atoms made up the world around us. (1) All matter is composed of infinitely small particles or atoms. (2) All atoms of a given element are identical to one another and (3) are...

01:26

Origin of Photosynthesis

Photosynthesis represents a fundamental biological process that transformed Earth's atmosphere and paved the way for complex life. Emerging roughly 3.4–3.8 billion years ago, the earliest photosynthetic organisms harnessed light energy to produce organic compounds. These anoxygenic phototrophs used electron donors like hydrogen sulfide (H₂S) or ferrous iron (Fe²⁺), rather than water, and did not release molecular oxygen (O₂) as a byproduct. Various groups, including green sulfur and purple...

01:19

Acid 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...

関連する実験動画