Sierra Madre, mountain system of Mexico<span>. It consists of the Sierra Madre Occidental (to the west), the Sierra Madre Oriental (to the </span>east<span>), and the Sierra Madre del Sur (to the </span>south<span>). </span>
Answer:
The answer is the different ages and geologic histories of the rocks.
Explanation:
The Northern Great Lakes region has a lot of untapped potential in terms of exploratory drilling for copper, nickel and other heavy metals. Mining companies are actively seeking permits to conduct exploratory drilling on the Superior National Forest of northeast Minnesota for instance. The state of Minnesota owns the mineral rights and they have granted permits to allow more than 100,000 acres of state mineral rights. This concerns environmentalists because new mines would be in addition to the many that already exist in the area like open-pit iron-ore mines. There is already a legacy of pollution and harm to the invaluable water quality in the area. Lake Superior contains 10 percent of the world's freshwater.
Mesophere i think as i believe its the coldest. :) but im not quite sure
