科學(xué)家說(shuō)他們已經(jīng)發(fā)現(xiàn)了6500萬(wàn)年前恐龍是如何滅絕的細(xì)節(jié)。一個(gè)地球物理學(xué)家小組正在分析墨西哥附近海底火山口的巖層。巖石中含有一顆巨大的小行星撞擊地球后災(zāi)難性后果的殘余物。科學(xué)家們說(shuō),他們提取的巖石層揭示了撞擊后巖石和沉淀物在暴露層中相互沉積而造成的破壞。普渡大學(xué)的地球物理學(xué)家杰伊·梅洛什說(shuō):“它告訴我們,在毀滅恐龍的那天,火山口內(nèi)發(fā)生了什么。所有這些混亂都直接記錄在核心。”
Scientists say the asteroid was around three to four kilometers wide. It smashed into the ocean and created a hole 160kms wide and 20kms deep. This triggered a chain reaction of earthquakes, tsunami, icecap melting, landslides and fires that forever changed the geology and life forms on Earth, killing off the dinosaurs. The asteroid's impact hurled out rock and minerals and created a massive crater. Molten rock fell back into the crater, which was then filled with ocean water from tidal waves. This water was full of soil, vegetation, animal life and other debris, all of which settled in layers ready for scientists to analyze millions of years later. The scientists say this layer-forming process took just a few hours.
科學(xué)家說(shuō)這顆小行星大約有3到4公里寬。它沖入海洋,形成了一個(gè)160公里寬20公里深的洞。這引發(fā)了地震、海嘯、冰蓋融化、山體滑坡和火災(zāi)的連鎖反應(yīng),永遠(yuǎn)改變了地球的地質(zhì)和生命形式,殺死了恐龍。小行星的撞擊將巖石和礦物拋出,形成了一個(gè)巨大的隕石坑。熔巖又落回火山口,火山口隨后充滿(mǎn)了海嘯產(chǎn)生的海水。這片水域充滿(mǎn)了土壤、植被、動(dòng)物生命和其他殘骸,所有這些都層層沉淀下來(lái),供科學(xué)家在數(shù)百萬(wàn)年后進(jìn)行分析??茖W(xué)家說(shuō)這一層形成過(guò)程只花了幾個(gè)小時(shí)。