コロラド州にある熱帯雨林は,白亜紀と三次紀の境界から140万年後のものです
1Department of Earth Sciences, Denver Museum of Nature & Science, Denver, CO 80205, USA. kjohnson@dmns.org
Science (New York, N.Y.)
|June 29, 2002
まとめ
コロラド州にある多様な下パレオセンの化石葉の遺跡は,クレタセア-第三期絶滅のわずか140万年後に繁栄した予期せぬ熱帯雨林を明らかにしています. この発見は,絶滅後の植物の回復に関する以前の仮定に異議を唱える.
科学分野:
- パレオボタニーは古植物学です.
- 古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
- 地質学 地質学 地質学
背景:
- クレタチウム-第3期 (K-T) の絶滅は,地球上の植生に重大な影響を及ぼし, Paleocene の種に乏しい植物コミュニティをもたらしました.
- 以前の理解では,パレオセンの植物多様性の低さは,K-T絶滅の余波に起因すると考えられていた.
研究 の 目的:
- コロラド州キャッスル・ロックで発見された,異常に多様性の高い低 палеオセンの化石葉の遺跡を調査するためです.
- K-T境界直後の多種多様な熱帯雨林の生態系を支えた環境条件を理解する.
主な方法:
- カッスル・ロック遺跡の化石葉の分析.
- 化石植物の比較と,現在の赤道熱帯雨林の廃棄物.
- デンバー盆地とララマイドフロントレンジの地質学的な文脈分析.
主要な成果:
- カッスル・ロック遺跡は,現代の赤道熱帯雨林に匹敵する,非常に多様な化石のゴミを展示しています.
- この多様性の高い植物群は,およそ6410万年前に存在し,K-T境界から140万年以内に存在した.
- 熱帯雨林は,デンバー盆地の縁のシナロゲン性堆積岩の中に位置していた.
結論:
- ララマイド・フロント・レンジによって生み出されたローカル・オログラフィック条件は,平穏な気候と併せて,熱帯雨林の形成を容易にした.
- この発見は,絶滅後の広範な回復ではなく,局所的な環境要因が,この地域の初期のパレオセンの熱帯雨林を可能にすることを示唆しています.
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