On the road again

Our stay in Fremantle has come to an end with the end of the Easter period. We have really enjoyed Fremantle as it has an interesting mixture of very old buildings and new and a Bohemian influence. Or maybe that was just because there was a festival on whilewe were there.  Yesterday we were invited around to the place of some people we met in York for coffee. He was a retired surveyor the same age as Geoff and both he and his wife were interesting and happy people. After chatting for a couple of hours we all caught the free bus into town and wandered around enjoying the holiday atmosphere.  Later they went back to their place and we stayed and spent a couple of hours at the Shipwreck Museum which was really good and was actually better than the Maritime museum. Heaps of history. 

Wreck of the Batavia 

Then we had a late lunch at a nice Pub. Bit expensive but nice food. Glad it is the kids inheritance we are spending and not our own money! Today we set off fairly early (for us) and headed north. Outer suburbs of Perth all shiny and new, lots of new subdivisions being opened up.  Highlight of the day was the Pinnacles. Amazing- acres and acres of these strange rocks. What are they?

The raw material for the limestone of the Pinnacles came from seashells in an earlier era that was rich in marine life. These shells were broken down into lime-rich sands that were blown inland to form high mobile dunes. However, the manner in which such raw materials formed the Pinnacles is the subject of debate and three theories have been proposed.

The first theory states that they were formed as dissolutional remnants of the Tamala Limestone i.e. that they formed as a result of a period of extensive solutional weathering (karstification). Focused solution initially formed small solutional depressions, mainly solution pipes, which were progressively enlarged over time, resulting in the pinnacle topography. Some pinnacles represent cemented void infills (microbialites and/or re-deposited sand), which are more resistant to erosion, but dissolution still played the final role in pinnacle development.

A second theory states that they were formed through the preservation of tree casts buried in coastal aeolianites, where roots became groundwater conduits, resulting in the precipitation of hard calcrete. Subsequent wind erosion of the aeolianite then exposed the calcrete pillars.

A third proposal suggests that plants played an active role in the creation of the Pinnacles, based on the mechanism that formed smaller “root casts” in other parts of the world. As transpiration drew water through the soil to the roots, nutrients and other dissolved minerals flowed toward the root—a process termed "mass-flow" that can result in the accumulation of nutrients at the surface of the root, if the nutrients arrive in quantities greater than that needed for plant growth. 

No room for us in the caravan park at Jurien Bay so we stayed in the overflow parking at the oval.