Day #55 Deskcrop: Glomeroporphyritic Basalt

Today’s deskcrop features a rather uncommon and distinctive glomeroporphyritic texture. It appears that the plagioclase phenocrysts in this rock nucleated at a small number of sites and grew into the surrounding magma in a radial pattern. Perhaps it should come as no surprise that the common name for rocks with this texture is “Daisy Stone”. This sample is a Keweenawan-aged basalt from the Algoma region of Ontario, though I’m intentionally putting its placemark in Lake Superior to protect the specific locality.

Glomeroporphyritic Basalt

Explore this and all of my 2010 Deskcrops and Outcrops in Google Earth!

Bookmark the permalink.

Comments are closed.