I’ve struck up a bit of an online friendship on G+ with someone who made an off-hand comment about one of the geology posts I shared. It was the one about 10 Reasons Geologists Are Weird. When a person reshares your reshare, and their profile photo shows them standing by some particularly yummy geology, wonderful things can happen. Like, being shown some delights and asked to identify them.
Here’s the accompanying description:
Grooves in rocks leading from the beach out to the sea. Flinders Victoria. The romantic in me wants them to have been made by glacial activity, but I don’t seriously think that’s the cause. They don’t appear to be manmade and they’re not regular – at the widest about maybe 30 – 40 cm, but only about 20cm or so through the rocks in shadow toward the top of the photo.
There are fantastic rock pools right through this area, lots of seaweed washed up on shore and great surf for those hardy souls not worried about sharks (there’s a seal colony not far away) or being swept over the rocks.
Right. So I’m supposed to be writing a review of Victor Stenger’s new book, researching for the metamorphic post on Rosetta Stones, beginning endless reading for a huge series on Mount St. Helens, planning for my upcoming trip to New Hampshire to see The Doctor (Evelyn, that is), and about ten billion other things, including research for another set of photos that S. Travers dangled in front of me (and are delicious). However. Comma. This can’t be resisted. This is a chance for me to see if all this studying geology really taught me anything at all.
So, here’s my thought process: Two strikes against glacial striations. They don’t seem quite right. They’re just not giving me that striation vibe. Too curvy, for one. And they’re in Australia, for another. My Australian geological knowledge is teh pathetic, but I don’t recall Australia being heavily glaciated recently.
It’s hard to tell from this one photo, but I’m getting a faulty feeling. I’m seeing possible faults. And the rock looks sort of a bit volcanic. I’ll crop the photo a bit, and changed the exposure, to get a better look:
So what could we have? Cracks and fractures in a volcanic rock, seems to me. Now, I could be spectacularly wrong. Certainly, I could be, and that’s why I’m posting this: so that my geologically-savvy readers can confirm or correct.
But let’s see if I can find some evidence to bolster my position.
First, we need to know where Flinders, Victoria is.
Right. That helps. See, I found this site while searching for Flinders, Victoria geology, and it talks about stuff near Barwon Heads. That turns out to be within the same area. So, what can we find here? Ah-ha! “The collision of the Australian Plate and the Pacific Plate during the Miocene created the SE-NW compressional stress field that Victoria currently experiences.” Now, that looks promising! Could be faults, indeed. There’s also mention of basalt. Excellent!
Now, let’s have a look for faults. I love finding faults. And I found plenty round Victoria. Dunno if that map’s public domain, so I’ll just have you give it a click and return.
Right. So. We’ve got faults, we’ve got basalt, but none of them specifically saying, “Flinders, Victoria has got basalt and faults all over the place.” So what else can we do to make the case? Look at the geologic map. Here, I’ll even clip the bit and point toward Flinders. It’s a government-produced map, hopefully they won’t mind.
So that bright yellow is noted as Older Volcanic Group. Yup. Volcanics abound there. I think we’ve got some pretty decent evidence, although without boots on the ground, I can’t be certain what I’m seeing. And, again, I could be spectacularly wrong. But even if so, I’ve just learned something about Flinders, Victoria, Australia that I didn’t know before. And got to see a photo of some very lovely rocks.
Also, you guys get something that is not so Pacific Northwest-centric. Along with a chance to kick my arse if I’m wrong. Which is what geology is all about, really, aside from the beer and the hammering and the stories rocks tell and the geologists (who rock) and – we could be here all day if I keep saying what geology’s all about, so I shall stop now. Over to my geos, who can tell us more.
That was fun. Very much so. So much so, in fact, that I’d like to extend an invitation for more photos. I can’t promise I’ll ever get to them, but if you want to send me photos of some delicious geology, along with the location they were taken and any observations you may have about them, it’s quite possible you, too, can see me attempt some geology-fu-by-photo on your very own mystery geology. Email them to dhunterauthor at yahoo dot com, if the fancy takes you.