第 1 單元，第 1 課

Analyzing the Rock and Fossil Records分析岩石與化石紀錄

背單字

relative age相對年代
The relative age of the layer is older than the one above it.
absolute age絕對年代
Radioactive dating gave an absolute age of 65 million years.
strata岩層（地層）
The canyon walls show colorful strata.
superposition疊置原則
By superposition, the bottom layer is the oldest.
original horizontality原始水平原則
Tilted layers break the rule of original horizontality, so they were moved.
lateral continuity側向連續原則
Lateral continuity lets us match layers across the canyon.
inclusions包裹體原則
The granite pieces are older, by the principle of inclusions.
cross-cutting relationships截切原則
The dike is younger, by cross-cutting relationships.
mass extinction大滅絕
A mass extinction ended the age of dinosaurs.

這課的重點字