From a crystal cave filmed for the original “Journey to the Center of the Earth” to seven weeks in Antarctica, Linda Welzenbach, senior research associate with the National Planetary Institute, took North Hall Middle School students across the planet and through millions of years Friday morning.
Welzenbach spoke to Russ Crain’s sixth-grade science classes and to eighth-graders in the Edison-Earhart Exploration Academy.
She was the Smithsonian Institution’s National Museum of Natural History’s collections manager for 15 years. She now lives in Galveston, Texas.
The crystal cave is in a volcano in Iceland, she said.
“I’ve been collecting rocks since I was 7,” she said, and talked about seeing the original “Journey to the Center of the Earth” film.
She has collected those rocks in all parts of the globe, finding most and buying some of them. She explained the properties of rocks: “Basically, rocks are a solid mixture of minerals,” she told the students.
One of her interests is analysis of meteorites, she said. A meteorite is a fragment of a meteoroid or asteroid that survives passage through the earth’s atmosphere and hits the ground.
She said one theory is that a huge asteroid hit the earth about 65 million years ago and created atmospheric conditions in which the dinosaurs could not survive.
She said geologists can “take what we learned here on earth and we take it out into space.” She referred to asteroids as missiles from outer space.
Welzenbach explained she spent seven weeks in Antarctica, looking for sample of meteorites. The U.S. has sent groups there since 1976, and they have found about 50,000 pieces of meteorites.
“Every single one (of the 50,000) is a puzzle piece about the development of earth,” she said.
She said about 10,000 to 15,000 samples of meteorites were found in the previous 500 years, and some of the meteorite pieces found in Antarctica have the same kind of gases trapped in them as samples found by U.S. ventures to Mars.
The evidence for meteorites from Mars is still circumstantial, she said, but it is what she called a 1 to 1 — or nearly perfect — match.
Welzenbach talked about the plates tectonic theory, which explains the features and movement of Earth’s surface in the present and the past.
She said was in Iceland three weeks ago and went snorkeling with her husband along the Mid-Atlantic Rift Zone, a mid-ocean ridge that separates the Eurasian and North American Plates. Iceland is part of that mountain ridge, which is mostly underwater.
Welzenbach noted that most of Iceland is volcanic and said a volcanic explosion in 2010 caused airplanes to be grounded to avoid the volcanic ash in the atmosphere.
The ash would fuse to the airplane engines, she said.
Welzenbach also discussed relatively young rocks, such as igneous rock that erupted in the 13th century, to sedimentary rock 283 million years old, to an iron meteorite 4.5 billion years old — the age of our solar system.
“There’s whole lots of rocks out there and they’re all different,” Welzenbach said.