听力文本

Greg Retallack was one of those involved in the search.
Greg Retallack是其中一位搜寻者。
He concentrated his efforts in Antarctica.
他的工作重点是在南极洲。
There was definitely a missing piece to this whole thing,
整件事中的确有一片空白，
and we struggled with, to find out what that was and the clue was in front of us actually for quite some time.
我们致力于找出它的真相，很多时候线索就摆在我们眼前。
In the middle 1990s, he led an expedition to see what was there.
上世纪90年代中期，他带领一支探险队前往考察。
It was really the trip of a lifetime and it was something I'd wanted to do for about 15 years before.
这是一生中最难忘的一次旅行，也是我15年前最想做的事。
The team spent weeks exploring the Permian rocks,
队员们一连几周都在考察二叠纪岩层，
but one bed of rock in particular attracted his attention.
尤其是有一个岩床引起了他的注意。

We knew it was the very latest Permian bed,
它是二叠纪末期的岩床，
and inside that bed there were quartz grains that had some very unusual features.
岩床中的石英颗粒具有很不寻常的特征。
Quartz is the most common crystal on earth.
石英是地球上最常见的晶体。
It's most frequently white and translucent.
通常是白色半透明的。
Most of the quartz is just like this grain that I'm on now and it's a very clear grain.
大部分石英就像我手头上这些颗粒一样，是非常纯净的颗粒。
Looking through the microscope, the light shines through it brightly, it looks white.
在显微镜下显得亮闪闪的，纯白无比。
But some of these crystals weren't white or clear.
但是有些石英晶体既不白也不透明。

视频及简介

如今，我们的世界生机盎然，随处可见活着的生灵。那么请想象一下所有这些生命有95%在一瞬间遭到了毁灭。这不是虚构的故事，它确实发生过。就在3亿年前的二迭纪，地球上还是一片丰饶繁荣的景象，然而2亿5千万年前的一场神秘事件导致了95%的物种灭绝，称为二迭纪生物大灭绝。这个凶残的杀手究竟是谁？是剧烈的地质运动、气候灾变，还是来自外太空的天体碰撞？为此，科学家们展开了一系列调查，试图解开“地球劫难日”惨剧背后的真相。