Basalt from way, way down south

CHRISTCHURCH, NEW ZEALAND–Andrew Collins, our Wooster Geology student abroad in New Zealand, has posted another set of photographs from his adventures. Of course they include field geology!  Here is one of his images from a recent outing:

Cave Rock near Sumner, which is a suburb of Christchurch, New Zealand. Photograph by Andrew Collins.

This view fits into one of our major themes this year: basalt!  We had plenty of it on the Mojave field trip, the Utah group dabbled in it, and the Iceland team is defined by this dense black rock. Now I’m no expert, but here’s my interpretation of the above outcrop: it looks like a basalt flow over a coarse conglomerate with a magnificent baked zone at the top of the conglomerate (the bright red) and a chilled zone at the base of the basalt.  What do you think?

About Mark Wilson

Mark Wilson is a Professor of Geology at The College of Wooster. He specializes in invertebrate paleontology, carbonate sedimentology, and stratigraphy. He also is an expert on pseudoscience, especially creationism.
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4 Responses to Basalt from way, way down south

  1. Stephanie Jarvis says:

    I think it looks pretty sweet, graffiti and all. Why is it such a bright red?

  2. Mark Wilson says:

    I’m hoping it’s not paint!

  3. Meagen says:

    Lava flows are often separated by flow-top breccias that contain cinder and are oxidized, giving them the bright red color. Also, if soils developed between eruptive events, the baked soil horizon can be highly colored – red, yellow. Just beautiful, really.

  4. Pingback: Wooster Geologists » Blog Archive » Wooster Geologist Experiences New Zealand Earthquake — Story Will Follow

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