The most useful method for determining temperatures one billion years ago is through ____.
A) oxygen isotope ratios in Greenland ice
B) rocks and fossils
C) historical records
D) tree rings

Question

Quizplus · Accepted Answer

The most direct and reliable method for determining temperatures one billion years ago is through analysis of rocks and fossils found in sedimentary deposits. Oxygen isotope ratios in Greenland ice provide information on temperatures back to about 800,000 years ago, but are not useful for studying temperatures one billion years ago. Historical records and tree rings are also not useful for studying temperatures one billion years ago, as they are limited to only the last few thousand years.

The Most Useful Method for Determining Temperatures One Billion Years