Extinct Tree, Alive Today

Martian Meteorites

Sometime long ago, a small meteorite crashed into the sands of the Sahara. In 2011, scientists discovered it and dubbed it NWA 7034 – nickname: Black Beauty. It was soon recognized as the rarest meteorite on Earth. Black Beauty came from Mars. Scientists know that because oxygen isotopes trapped within it match those in the Martian atmosphere. Because that atmosphere is so thin, Mars is not well protected from asteroids. When they impact the surface, they explode off chunks of rock. Some of these travel out into space, where they drift for years, before becoming trapped in Earth’s stronger gravity field, and pulled to us. Most burn up as they rocket through our much thicker atmosphere. We’ve only recovered 74,000 meteorites worldwide that have made it to Earth’s surface. The large majority are fragments of asteroids; less than 400 are from Mars. And of those, there is only one Black Beauty. That’s because it’s brecciated, meaning made up of tiny chunks of many different rocks from the surface of Mars, that have been accreted together over time. Geologists can study how the breccia formed and ‘read’ each of the small fragments within it to interpret their origins, and better understand the geology of Mars. That makes Black Beauty, though just the size of a tennis ball, the most studied meteorite on Earth.

Mount St. Helens Eruption

The blast was over a thousand times stronger than Hiroshima, heard 700 miles away. It killed 57 people and countless animals. This was the eruption of Mount St. Helens 45 years ago in Washington, the deadliest, most damaging volcanic event in modern US history. Surprisingly, in America today there are 169 active volcanoes. Most are in Alaska. A few in Hawaii have small eruptions regularly. There are 20 volcanoes in Washington and Oregon, where the Juan de Fuca tectonic plate subducts under North America, melting as it’s pushed down into Earth’s mantle, and rising to produce volcanoes at the surface. A few are active, but St. Helen’s is different. It’s 25 miles west of the others, where the tectonic subduction zone is 20 miles nearer the surface. In 1980, magma blasted sideways through a mile long gash on the side of the mountain. on the side of the mountain, flattening trees in an 8-mile radius. Pyroclastic flows set forest fires. Mudslides filled lakes and diverted rivers, causing massive floods. But within weeks, fireweed sprouted from roots. Lupine and huckleberry crept across the landscape. Insects, burrowing animals and elk soon returned. Aquatic ecosystems rebounded. Today, the top of the peak is gone, replaced by a huge caldera. But new trees have grown tall and the forest has returned.

Extinct Tree, Alive Today

Thought to have been extinct for over 2 million years, a cluster of Wollemi pine was discovered by hikers in a secluded canyon outside of Sydney, Australia in 1994. Guarding this area from humans and fire along with cultivation and conservation efforts by botanical gardens have safeguarded this unique species. Now, advances in decoding the Wollemi pine genome may provide the secret to successfully preserve this critically endangered species.

Grand Teton National Park

Grand Teton National Park contains North America’s youngest mountain range: the towering “Tetons.” While the range formed by extension along a tectonically simple “normal” fault, the Teton Fault is unique because it has moved nearly 33,000 ft (10 km) in just ten million years. Preserving astounding natural beauty and a human history stretching back at least 11,000 years, the national park was first established in 1929.

Mystery of the Wallace Line

The Wallace Line, a boundary separating the unique species of Australia from those of Southeast Asia, has long fascinated scientists. Exploring the influence of plate tectonics, glacial periods, and geographic isolation may hold the answer to this mystery.