Here, spectacularly large groups of scolecite, heulandite, apophyllite, and associated minerals occurred in cavities in flood basalt. |
The basalt lava in particular has been, and is still being, extensively quarried for road aggregate in many large quarries on those mountains. |
It can be found in fissure veins and brecciated amygdaloidal basalt lodes but not in the conglomerate lodes. |
The Haluut Bulag melange contains lenses of limestone, sandstone, chert, tuff, minor acid volcanic material, and vesicular basalt. |
Here the rock formed when lava flowed into a freshwater lagoon and quickly altered into spilite basalt. |
A serpentine flow meanders through formations of smooth pahoehoe lava and rough aa lava, the same forms common in basalt lavas. |