万物简史 第275期:砰!(10)

搜索关注在线英语听力室公众号：tingroom，领取免费英语资料大礼包。

　　another development—wholly unrelated on the face of it, 另一件大事——表面看来完全没有关系，

　　was quietly unfolding in Italy with the work of a young geologist² from the Lamont Doherty Laboratory at Columbia University. 在意大利悄悄揭开序幕，由于哥伦比亚大学莱蒙特·多赫蒂实验室的一位年轻地质学家的工作。

　　In the early 1970s, Walter Alvarez was doing fieldwork in a comely³ defile⁴ known as the Bottaccione Gorge⁵, near the Umbrian hill town of Gubbio, 20世纪70年代初，在距离翁布里亚地区的山城古比奥不远的地方，沃尔特·阿尔瓦雷斯正在一个名叫博塔西昂峡谷的峡道里作实地考察。

　　when he grew curious about a thin band of reddish clay that divided two ancient layers of limestone⁶, 他突然对薄薄的一层淡红色黏土发生了兴趣。

　　one from the Cretaceous period, the other from the Tertiary. 这层黏土把古代灰岩分为两层，一层属于白垩纪，一层属于第三纪。

　　This is a point known to geology as the KT boundary, and it marks the time, sixty-five million years ago, 这在地质学里被称之为KT界线。它标志着6500万年前

　　when the dinosaurs⁸ and roughly half the world's other species of animals abruptly⁹ vanish from the fossil record. 恐龙和世界上大约一半其他种类的动物从化石记录中突然消失。

　　It is KT rather than CT because C had already been appropriated for Cambrian. 是KT界线，而不是CT界线，因为C已经用来代表“寒武纪”。

　　Depending on which source you credit, the K comes either from the Greek Kreta or German Kreide. K不是来自希腊语Kreta，就是来自德语Kreide。

　　Both conveniently mean "chalk," which is also what Cretaceous means. 二者的意思都是白垩，这也是“白垩纪”的意思。

　　Alvarez wondered what it was about a thin lamina of clay, barely a quarter of an inch thick, 阿尔瓦雷斯不大明白，只有6毫米左右厚的薄薄一层黏土，

　　that could account for such a dramatic moment in Earth's history. 怎么能说明地球史上这么个戏剧性的时刻。

　　At the time the conventional wisdom about the dinosaur⁷ extinction¹⁰ was the same as it had been in Charles Lyell's day a century earlier, 当时，关于恐龙灭绝的时间，人们通常的看法与一个世纪前查尔斯·莱尔时代一样，

　　namely that the dinosaurs had died out over millions of years. 即恐龙灭绝于几百万年以前。

分享到：