Vesicular basalt

3D Model

This vesicular basalt from the UoN colection contains vesicles up to 2 centimetres in diameter. The specimen could also be referred to as ‘amygdaloidal’ because of the partly/wholly filled nature of the vesicles. The host rock contains pyroxene (augite), plagioclase and minor altered olivine. The vesicles are partly infilled by secondary calcite and a number of zeolites. Although similar to may basalt flows in eatern New South Wales, this specimen was collected from Cordes Junction in Arizona. I am unsure of the age, but it is likely to be part of extensive the late Miocene to Pliocene laval flows in the area. These flows are also the yougest rocks in the Grand Canyon area.