Places I've been: Organ pipes National Park, Victoria, Australia

 

Looking east at the leading edge of the organ pipes structure.

The second stop on our Igneous Geology field trip is the Organ Pipes National Park. As this was part of our first date, I've already posted about this location so won't go into much more detail. I will however show to pictures of new things I got to see this time:

 

Basaltic columns near the edge of Jacksons Creek just past the Tesselated Pavement. Hexagonal columns are created by the contraction of the cooling lava cracking at approximately 120 degrees. These cracks propagate downward as the body of lava cools creating columns.

 

The contact between the basalt and the underlying sediments. The white line is the metamorphised sedimentary rock, and is about 5mm thick.

 

Just below the contact, something I've never noticed before!

 

A conglomerate containing rounded quartz pebbles (1cm) and large angular sandstone cobbles (up to 10cm). This indicates the rock is not the Ordovician sediments but reworked into terrestrial sediments from the Eocene.