Geology around town - Collins St, Melbourne

Bubble trails in basalt on the ATO building on Collins Street, Melbourne. I like the sections in the upper left where there are sections with differently sized bubbles. I'd suggest these were busy cooling before being pried away from the rest of the block by locally increased degassing.

Fossil leaves - Illawarra coal measure, New South Wales

Both of these images are leaf fossils from the Illawarra coal measures in New South Wales. They have been dated to the Permian! They were provided by Dr C. Mays as teaching samples for a class I assisted teaching at Monash University and I couldn't resist snapping a few photos. They're lovely examples of preservation.

Places I've been: Lake Parumbeet, Victoria, Australia

 The old parumbeet quarry.

 

X-beds found in ash deposits created by pyroclastic flows.

 

Partial view from the crater rim. The lake is the biggest maar crater that's currently filled with water. Jackson van der Hove (Monash University) is currently working on a number of geophysics surveys to determine how many vents are in this maar.

Historic places I've been - Thailand

In May 2013 I had the opportunity to goto Thailand. That is to say, my partner at the time wanted to change his Australian visa so needed to leave the country while it was approved. So, we went to Thailand. I quite enjoyed Bangkok but he hated crowds so we headed south pretty soon after arriving. Rather than go to Phuket or any of the other popular East coast tourist islands we went to Koh Phayam, Ranong, located near the border with Burmah. The island used to be a cashew plantation. There are still cashews all over the place but they are slowly getting over taken by new, smaller rubber tree plantations. The locals are very friendly and while there is a tourist season it doesn't last all year and it's not as commercialized as islands in the east. To get to the island you take a ferry from the mainland. The ferry services a number of local islands, so you end up taking an hour or two cruise through the beautiful waters of Adaman Sea.

Once on the island we stayed on Ao Yai Bay at Bamboo Bungalows and did the usual touristy things of enjoying the beach, enjoying the food on offer and general exploring. As it was past tourist season, many entertainments weren't on offer (i.e scuba diving & fishing tours) so we hung out on the beach and caught some sunlight and appreciated the water and the wildlife.

To put this in perspective, I haven't had a holiday that involves relaxing in my entire adult life. My traveling has usually involved either medieval events, visiting friends or geology related activities. So this was novel to say the least. Having spent far too many years in the PhD research space, I got bored after a couple of hours of relaxing. So I decided to do geology. I noticed the locals were using a conglomerate to line a lot of the paths so I decided to find out where it was coming from.

 Construction with conglomerate.

The southern end of our beach appeared to be a highly weathered granite as did the northern end. The clues were also in the sand as they were feldspathic and dark minerals lined the troughs of the ripples closer to the outcrops. At my insistence we visited many a beach until I could find the conglomerate in it's natural state. I didn't manage to find it until our second last day there so it kept me happily occupied for quite some time.

The conglomerate containing well rounded sedimentary pebbles. I'm pretty sure this is post granite but I couldn't find pieces of the granite in the conglomerate.

My Koh Phayam mud map, forgive the roughness, the paper is made of coconut fiber and doesn't lend itself to smooth lines.

Random Fossils

Random fossils spotted on a co-workers desk at Monash University. I have no idea where they are from but they're lovely!

 

Urchin and coral polyp? fossils spotted on co-workers desk at Monash Uni, photo by Ant.

Places I've been - Dights Falls, Melbourne

Looking south at Dights Falls, Yarra Bend Park, Melbourne. Photo by Ant.

Here you can see the completed Dights falls (the fish weir is under the POV). Repairs and maintenance have been ongoing for sometime now. To the right are the apartment blocks of Abbotsford and in the foreground it is possible to make out the basalt blocks used to construct previous versions of the falls.

In the early 19th century, this was the location of a water powered flour mill. The falls were important as they marked the boundary between brine and fresh water on the Yarra River. Downstream of the location was an industrial zone and upstream was suitable for residences and farming (see Collingwood Childrens Farm).

Geologically speaking the bank the photograph is taken from is composed of basalts from the Newer Volcanics while on the far side of the river are Silurian turbiditites. The turbidites are deep ocean sediments where muds are generally deposited. Occasionally a significant storm or landslide event will result in the deposition of a layer of sands. The interbedded sands and muds of the turbidites make up much of geology east of the City of Melbourne and are interestingly tilted and folded.

In the image above, the sediments strike approximately North-South and dip around 45 degrees to the East. There is a locally thick bed of sandstones (approximately 1m thick) in this deposit which is responsible for the development and location of Dights Falls.

Fossils - Ceratopsian

This is a lovely example of a baby Ceratopsian. It is one of a group of herbivore dinosaurs. The best known ones are the Triceratops or other varieties from Mongolia however the earliest ones identified come from Gondwana in the Early Cretaceous. This one was at the Australian Dinosaur exhibit at the Geelong Wool Museum. I had heard that some of the Ceratopsian groups had been amalgamated as scientists determined that their neck frill gets hollow as it grows due to weight requirements so some teenage Ceratopsians had been miss-classified as a separate.

Baby Ceratopsian, photo by Ant.