For thousands of years the ancient Andean people revered gold and created exquisite gold art objects. This ultimately led to the fall of the Inca Empire when the metal lured Spanish conquistadores high into the Andes. Gold continues to be mined today, with adverse consequences for the environment and many Andean people.
Iron-oxide concretions – curious-looking dark spheres – can be found by the hundreds of thousands in the dramatic red and white outcrops of Navajo Sandstone in Utah. The concretions typically consist of a sandstone core surrounded by a thick iron-rich rind, and they have an interesting geologic history and Native American cultural history. They also resemble Martian spherules or "blueberries", and may share similar origins.
Towering cliffs, plateaus, arches, and narrow canyons are iconic symbols of southern Utah’s Red Rock Country. Another type of landform captured my attention during recent explorations: mile after mile of gently rolling rock-covered terrain, giving the impression of being surrounded by an ocean of sandstone. An arid sand sea of shifting dunes created these rocks many millions of years ago.
The volcano recently erupting in Africa–Mount Nyiragongo–is one of the most active on our planet. Eruptions in 1977, 2002 and now beginning in May 2021, have resulted in a significant number of fatalities and extensive damage in the nearby and densely populated city of Goma. If scientists were calling the shots, they would relocate Goma and designate the region beneath this active volcano as a national park.