まとめ
南極の花岩は30億年前のもので,アフリカのスワジランドシールドに匹敵する. これは,大陸の漂流が南極とアフリカの間に適合し,地質的なタイムラインを結びつけることを示唆しています.
科学分野:
- ジオクロノロジー (Geochronology) について
- プレート・テクトニクス (プレート・テクトニクス)
- 地質学 地質学 地質学
背景:
- 大陸漂流理論は,地球の過去の陸地の再構築を提案しています.
- 南極とアフリカの地質学的な形成は,彼らの共通の歴史のヒントを保持しています.
研究 の 目的:
- 南極大陸から採取した古代の岩石の標本に日付を付けています.
- 大陸の漂流モデルに基づいて,南極とアフリカの間の潜在的な地質年代学的な関連を調査する.
主な方法:
- バイオタイト・グラニットサンプルのルビジアム・ストロンチウム年代測定.
- 大陸の漂流再構築の分析 (ダイッツとスプロール).
主要な成果:
- 南極のジュル・ピークスから採取したバイオタイト・グラニートの試料は,約30億年前の年齢を示した.
- 大陸の漂流の再構築は,南極のマーサ公主海岸とアフリカのスワジランドシールドの間の適合を示唆しています.
- スワジランド・シールドには,約30億年前の花岩も含まれています.
結論:
- 南極の花岩の30億年の年齢は,アフリカのスワジランドシールドの年齢と一致しています.
- この年齢一致は,これらの地質学的な地域を結びつける,提案された大陸の漂流の適合を裏付けています.
関連する概念動画
02:48Radioactive 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.
03:18Nuclear Stability
Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10−15 meters, a nucleus is quite small compared to the radius of the entire atom, which is about 10−10 meters. Nuclei are extremely dense compared to bulk matter, averaging 1.8 × 1014 grams per cubic centimeter. If the earth’s density were equal to the average nuclear density, the earth’s radius would be only about 200 meters.
To hold positively charged protons together in the...
To hold positively charged protons together in the...
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,...
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.
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.
01:21Three-Domain System of Life
Ribosomal RNA (rRNA) sequence analysis revealed three distinct groups of cells: eukaryotes, bacteria, and archaea. In 1978, Carl R. Woese proposed the concept of domains, a taxonomic level above kingdoms, to differentiate these groups. He suggested that archaea and bacteria, despite their similar appearance, represent separate domains. Domains differ in rRNA, membrane lipid structure, transfer RNA, and antibiotic sensitivity.In this classification, animals, plants, and fungi belong to the...