In Mexico, researchers have drilled rock cores from the Chicxulub crater.

在墨西哥，研究人员从希克苏鲁伯陨石坑钻出了岩心。

They took a rock core from the east coast, which has excellent sediment records-good evidence of extreme seasonal variations.

他们在东海岸采集了一块岩心，这块岩心具有极好的沉积物记录——这是极端季节变化的充分证据。

Over the years, assassinations, major scandals, mass protests, and political battles have rocked its core.

多年来，暗杀、重大丑闻、群众抗议和政治斗争动摇了它的核心。

Back home, he sent samples from the rubble field, the rock core and others from the path the landslide might have taken for dating.

回到家后，他把从碎石场、岩心和滑坡可能经过的路径上采集的样本送去进行年代测定。

Geologists got rock cores from two miles down, at the active fault zone. They looked at those fault rocks with an electron microscope. And they found an incredibly thin coating of clay polish on the rocks.

地质学家们在断层带活跃区域的两英里深处采集了岩心样本，他们利用电子显微镜研究那些断层岩，发现这些岩石上覆盖着极薄的一层粘土" 抛光蜡" 。