Date Idea: 26/11/2014 - Yucatan, Mexico

Cenotes (sinkholes and cave systems) in Yucatan, Mexico. Image and good explanation of the features to be found from this blog.

Date Idea - 19/11/2014 - Patagonia, Chile

Marble Caves of Patagonia, Chile. Photo credited to Robert O'Duill on this website

Date Idea - 12/11/2014 - Termas Geometricas, Chile

Because you might as well relax and enjoy yourself if you're planning on spending sometime looking at rocks I present: Termas Geometricas near Pucon in Chile. It offers a range of springs in a natural setting (some with waterfalls) for approximately $40 AUD per person. It's on the list!

Image from here - a pretty good website full of things to see and do in Chile.

Places I've been: Inverloch Pt 3 - Fossils!

Tiny mammal jaw found at Inverloch - image by Steve Morton (Monash University)

The dinosaur dreaming digsite at Flat Rocks, Inverloch is a rather special as it has yeilded over 10,000 fossils from a time when the rift was developing between Australia and Antarctica. I find one of the most significant to be a tiny mammal jaw (above) which is smaller than a fingernail. It is due to this fossil that all material removed from the fossil rich layer must be broken into sugar cube sized chunks before being assessed for fossil material. 

Map of fossil locations courtsey of the Dinosaur Dreaming website.

The fossils themselves are found in a flood deposit / conglomerate which formed as part of a braided river environment, now called the Strazlecki Group. A large variety of fossils have been found in this region (above) and I'm told the small greyish lump in the photo below is one such fossil fragment.

 

Also found in this area (but away from the fossil extraction site) are a set of dinosaur footprints. Located on the shore platform, they are slowly erroding and probably won't exist in a couple of years. This year I took a picture with my camera case for scale. The footprints are outlined in a slightly darker sediment and feature two three towed footprints overlaid on each other. The feet themselves are about 1.5x bigger than mine (see my hiking shoe toe for scale as well)

If you want more information about this site, or are interested in joining the team at the dig on their next summer campaign, checkout the dinosaur dreaming website. If you want some awesome pictures of some of the fossils they've recovered, this post  by Tom Rich on The Conversation has some great images.

Counter top geology - Serpentine

I spotted a broken slab of serpentine at the Kilsyth Bargin Centre the other day. It hasn't photographed amazingly well because it's polished but it was a rather nice sample. Not what I'd pick for a bench though, a little soft for longevity.

The broken end showing the polished section (deep green) and the talc-y greasiness of the rock

Historical places I've been: Tower Hill Maar, Victoria

 

It's been a while since I've done one of these. This is an image of Jim Driscoll and I at the Tower Hill Maar in Western Victoria, 2013. He's into sedimentology and geothermal research and is just about to finish his PhD at Monash University. For the last couple of years we've assisted with the JMSS geology field trip and this is one of the locations we take the students.
This is a nested maar system is the result of a sequence phreatomagmatic eruptions (note the huge number of layers behind us) resulting in a complex structure seen today. Multiple scoria cones are surrounded by a crater lake (which is probably formed by multiple vents). The countryside around Tower Hill is covered by these ash and scoria layers which all slope gently away from the site of the volcano.The volcano also ejected larger bombs, the impact of one can be seen over my right shoulder. The shape of these craters can help determine the trajectory of the bomb and allows volcanologists to determine the sequence in which the vents were actives.