Vesicular basalt - Isle of Mull
 >View Microscope
Fact sheet
Description: 

This vesicular basalt comes from Creag Brimishgan on the Isle of Mull, Inner Hebrides, Scotland. It was erupted during the Paleogene igneous province that erupted in a short time period across Scotland, northern England, Northern Ireland and Greenland. The rock was subjected to low-grade metamorphism and fluid ingress as later lavas covered this one, and the cavities (vesicles) that originally formed as gas bubbles in the lava were filled with secondary minerals such as the zeolite mineral pumpellyite.

In thin section the rock is a coarse grained basalt, with a framework of plagioclase laths 1-3 mm long that have been extensively altered to clays. Pyroxene is much less altered and exhibits a poikillitic texture (a large grain containing smaller grains of another species). Vesicles appear angular rather than spherical and are filled by fine-grained pumpellyite lining the cavities and forming delicate rosettes of needle-shaped crystals.

In Place
In Time
infoImage: 
Location description: 
Creag Brimishgan, Isle of Mull, Scotland
Accuracy:
Location precision: 
Moderate
Timescale:
Timescale: 
Paleogene
Ma = Millions of years ago
In Focus
Theme:

Theme:

What\
Type:
Type: 
metamorphic
What\
Category:

Category:

What\
Rock-forming minerals:

Rock forming mineral:

What\