What were the desert valleys of the Great Basin like 17,000 years ago? What does the distribution of the ice-age lakes in the Great Basin reveal about the climate 20,000 years ago?
How do we reconstruct ancient climate in this region? Where was the southerly track of northern winter storms during this time period?
What will be an ideal response?
Answer: The desert valleys were deep, freshwater lakes. The distribution of ice-age lakes in the Great Basin tells us that the climate was much wetter 20,000 years ago. We reconstruct ancient climate by finding records of past vegetation. The preserved nests of packrats provide a record of vegetation history, because packrats collect sticks and brush into dense artificial thickets. Northern Mexico
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