Martian Volcanoes Once Chose Violence

Structures in rocks imaged by the Spirit rover reveal similarities to ignimbrite rocks here on Earth, which means some very ancient eruptions were more explosive than expected.

Beth Johnson
4 min readMay 11, 2022
IMAGE: Outcrop of olivine-rich bedrock in Gusev crater observed with Spirit’s Panoramic Camera (Pancam) in 2005. CREDIT: NASA/JPL/Cornell/ASU

We now turn to volcanos on Mars. And specifically, we’re going to talk about a point in time when some of those volcanoes may have chosen violence.

First, some background information. Almost twenty years ago, there were two little rovers that landed on Mars — Spirit and Opportunity. They were both planned out as ninety-day missions, but as I’m sure a lot of you recall, they lasted far longer than that. And about sixteen years ago, Spirit explored Gusev crater and found bedrock that was rich in olivine. Cool, olivine. If you’re like me, you probably are asking, “What’s olivine?” I’ve actually asked that question.

Olivine is a green mineral that comes from magma in the mantle, both on Mars and here on Earth. It’s not really unexpected, but it is definitely a clear signal of some kind of volcanic activity occurring that brought those rocks to the surface.

Fast forward to the past year on Mars and a newer, much bigger rover named Perseverance. You know, the rover the helicopter is running around with. Anyway, there are…

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Beth Johnson

Planetary scientist, podcast host. Communication specialist for SETI Institute and Planetary Science Institute. Buy me a coffee: https://ko-fi.com/planetarypan