This line marks a deep ocean channel that remained water - filled even during past ice ages, when sea levels saw channels between other islands in the region dry out. (newscientist.com)
The different patterns can be used to hunt for now - disappeared glaciers from past ice ages. (livescience.com)
The resulting lower atmospheric CO2, the argument goes, would mean lower temperatures, suggesting that the mechanism was at least partially responsible for triggering past ice ages. (sciencemag.org)