南アメリカの地質学的観察
- 言語:
- 英語
- 状態:
- 完全な作品
- 著者性:
- 著者自身による
- テキストの状態:
- スキャンのノイズは検出されていません (全文に対する自動測定で、人の目では確認していません)
- 分量:
- 約 150,000 語 · 701 節
この作品を引用
- APAチャールズ・ダーウィン. (n.d.). Geological Observations on South America [南アメリカの地質学的観察]. Digital reproduction: SigPhi. https://sigphiai.com/ja/works/charles-darwin/geological-observations-on-south-america
- MLAチャールズ・ダーウィン. Geological Observations on South America [南アメリカの地質学的観察]. Digital reproduction, SigPhi, https://sigphiai.com/ja/works/charles-darwin/geological-observations-on-south-america.
- Chicagoチャールズ・ダーウィン. Geological Observations on South America [南アメリカの地質学的観察]. Digital reproduction, SigPhi. https://sigphiai.com/ja/works/charles-darwin/geological-observations-on-south-america.
SigPhi が再現している版の参照です。SigPhi はそのデジタル再現であり、出版者ではありません。版の刊行年はメタデータにないため「n.d.」とし、訳者は記録がある場合のみ記します。
何についての本か
ビーグル号の航海からダーウィンが取り出した地質学三部作の第三巻にして最終巻。一八四六年刊。
背景と歴史
ダーウィンは博物学者として乗り込んだが、帰ってきたときは何よりまず地質学者であった。以後何年も、彼は他の何よりもそれで知られていた。ここで彼は、チリ海岸の隆起した海成段丘、化石層、山脈、火山を記述し、この大陸が計り知れぬ年代をかけてゆっくりと隆起してきたと結論する。決め手となった経験は目の当たりに得たものだ。一八三五年、彼はチリにいて、地震が海岸を目の前で数フィート持ち上げるのを見た。話から抜け落ちがちなのがこの一片である。深い時間という観念、そして気づかぬほどの変化が積み上がるという観念は、ライエルの地質学と、陸で見たものとから来た。それがなければ『種の起源』の議論は立たない。
これは編集上の背景であり、引用できる典拠ではありません。作品本文の一節とは異なり、これらの記述はコーパスで検証できません。
cleavage arise from the development of new minerals, chlorite, epidote or mica, and that in this way a complete graduation from slates to true schists may be traced. Darwin further showed that in highly schistose rocks, the folia bend around and encircle any foreign bodies in the mass, and that in some cases they exhibit the most tortuous forms and complicated puckerings. He clearly saw that in all cases the forces by which these striking phenomena must have been produced were persistent over wide areas, and were connected with the great movements by which the rocks had been upheaved and folded. That the distinct folia of quartz, feldspar, mica, and other minerals composing the metamorphic schists could not have been separately deposited as sediment was strongly insisted upon by Darwin; and in doing so he opposed the view generally prevalent among geologists at that time. He was thus driven to the conclusion that foliation, like cleavage, is not an original, but a superinduced structure in rock-masses, and that it is the result of re-crystallisation, under the controlling influence of great pressure, of the materials of which the rock was composed. In studying the lavas of Ascension, as we have already seen, Darwin was led to recognise the circumstance that, when igneous rocks are subjected to great differential movements during the period of their consolidation, they acquire a foliated structure, closely analogous to that of the crystalline schists. Like his predecessor in this field of inquiry, Mr. Poulett Scrope, Charles Darwin seems to have been greatly impressed by these facts, and he argued from them that the rocks exhibiting the foliated structure must have been in a state of plasticity, like that of a cooling mass of lava. At that time the suggestive experiments of Tresca, Daubree, and others, showing that solid masses under the influence of enormous pressure become actually plastic, had not been published.…