Scottish naturalist James Hutton (1726-1797) attempted to formulate geological principles based on observations of rocks.
Earth cycles Global cycles of life-giving elements
Tightly folded rocks like the ones in this outcrop illustrate how rocks can be deformed at high temperatures and pressures.
Earth cycles Global cycles of life-giving elements
This petrified tree was part of a grove of redwoods buried by a volcanic blast more than three million years ago.
Earth cycles Global cycles of life-giving elements
A major ore deposit that was formed by the flow of metal-laden seawater through hot rocks is at the Kidd Creek Mine in Ontario, Canada.
Earth cycles Global cycles of life-giving elements
Since their discovery in 1886, the Witwatersrand deposits have yielded more than 40,000 tons of gold.
Earth cycles Global cycles of life-giving elements
Modern black smokers, like ancient black smokers, contain complex mixtures of fine crystals of iron, copper, and zinc sulfides.
Earth cycles Global cycles of life-giving elements
Some ore deposits now exposed on land originally formed in the oceans.
Earth cycles Global cycles of life-giving elements
Chromite is usually one of the first minerals to crystallize in basaltic magma.
Earth cycles Global cycles of life-giving elements
Underwater steam explosions and the collapse of the vent structures resulted in great piles of fragmented sulfides.
Earth cycles Global cycles of life-giving elements
This massive ore is composed of the copper-rich sulfide minerals covellite (purple and blue) and bornite (blue-black).
Earth cycles Global cycles of life-giving elements
