Tuesday, April 25, 2017

Planetary Surface Processes Fieldschool!

Hello everyone!

This week we are busy getting prepared for field school!  Western offers a Planetary Surface Processes Field School, which is a two-week tour around Arizona and Utah to get acquainted with the geomorphological processes affecting terrestrial bodies in our solar system.  What shapes the surface of planets?  Here are the main culprits:

1. Tectonics
2. Volcanism
3. Impact cratering
4. Erosion and weathering (Includes liquid, aeolian, glacial, and gravity driven processes!)

Not all planets and moons have been affected by all of these.  While we see river channels on Mars, we don't see them on Mercury.  Additionally, not all fluvial processes necessarily H2O water - there are many fluvial-like channels formed by hydrocarbons on Titan!

Tectonic processes also differ across planetary bodies. Earth is the only planet to show developed plate tectonics, although Venus shows mantle-plume tectonism forming volcanoes similar to Hawaii, and many planets and moons show compressional and extensional tectonic deformation.

All planets and moons in the solar system are affected by impact processes - meteorites don't discriminate!

With the exception of icy bodies, volcanism also appears pervasive across the solar system with most planets and moons showing evidence for past volcanism, or even modern volcanism in the case of Jupiter's moon Io.

Our planet is overall an excellent laboratory for studying the geology of other planets and moons. We expect to see most of these processes on our field trip!

For example, Arizona is located within the southwestern US basin and range province.  This is an area of tectonic extension causing regional thinning of the crust.  The pulling apart of the crust produced "horst and graben" topography which results in the steep sided valleys that we will see in Canyonlands National Park, Utah. Similar terrain can be seen in on many other planetary bodies, including Venus and Jupiter's moon Ganymede.

We will be visiting the Marysvale Volcanic Complex in Utah.  This field is characterized by pervasive many cinder cones and calderas.  The most recent volcanism is bi-modal, meaning there are both basaltic and rhyolitic lava flows.  Most volcanism in the solar system is basaltic, but there is increasing evidence for felsic volcanism on different planetary bodies, such the Moon. One region on the Moon, the Compton-Belkovich volcanic complex, contains a dozen steep-flanked domes interpreted to be from viscous lavas, like the rhyolitic volcanic domes found in the Marysvale Volcanic Field. The bimodal volcanism on the Moon and in Utah both likely formed via the same mechanism.

Some of the more famous sites we will be visiting include Meteor Crater (yup, that's its official name) and the Grand Canyon.  Meteor Crater is one of the best preserved simple craters in the world, and is a classic analogue for studying impact craters on other planetary bodies.  The Grand Canyon is world-class example of how fluvial activity coupled with tectonic uplift can deeply incise into rock. The largest known canyon in the solar system, Vallis Marineris, is found on Mars and is 5x longer and over 4x deeper than the Grand Canyon!

Overall, this will be a great trip, and I look forward to what I will be able to share with you!

You can follow our adventures on Twitter, using the hashtag #PS9605 (our course number at Western)



  1. A new paper suggests plate tectonics might also affect Europa: http://www.nature.com/news/plate-tectonics-found-on-europa-1.15851

  2. Also, although I'm sure Io is affected by impact cratering, it is the only solid body in the solar system with zero impact craters on it.

  3. Finally, Meteor Crater's official name is Barringer crater: http://www.passc.net/EarthImpactDatabase/barringer.html (but the two names are used pretty interchangeably)