Photo of the Week

Geology Photo of the Week # 18 – Jan 13-19

Matt Herod January 14, 2013

The photo for this week is something that I stumbled upon the other day when looking for directions to a friend’s house. It is a large scale concentric feature on the landscape and is located about 40 minutes north of Kingston near the hamlet of Holleford. I have actually been to this location in person when I was a geology undergrad and so I had the benefit of prior knowledge to help me interpret this feature. However, the person who discovered the feature, using aerial photos in the 1950’s did not. Try to guess what you think this could be?

Well, have you thought about it? It is actually an impact structure left behind from a meteorite impact. It was first identified by Dr. Carlyle Beals using air photos and has since been the subject of geophysical study and drilling by the Geological Survey of Canada that has confirmed its identity as an impact feature. It is about 2.5 km in diameter and only 30m deep as it has been extensively eroded by glaciations since its impact about 550 million years ago in the Ediacaran. Nonetheless, the topography still remains and the geophysics confirm it. The geophysical surveys showed gravity and magnetic anomalies and drilling found evidence of shocked quartz, which is a smoking gun for meteorite impacts.

I think it is pretty cool that features like this are visible in Google Maps/Earth and available for anyone to discover or rediscover in this case. I imagine that there are dozens or even hundreds of features like this around the world that have not been discovered yet or realized to be impact related. I expect there is still room for exploration now that tools like these are available to everyone and could shed light on the tortuous history our Earth has experienced.

Cheers,

Matt

Geology Photo of the Week #17 – Jan 6-12

Matt Herod January 7, 2013

Happy New Year everyone! I hope that you all had relaxing and enjoyable holidays. I sure did. It is time to start off the new year with the 17th edition of the photo of the week. Here in Ottawa it is a balmy -19 degC with the wind chill making it feel like -28 degC right now! Happily I am toasty and warm inside…for now. If you’re curious the coldest place in Canada at the moment is Eureka, Nunavut at -40 degC and a windchill of -46 degC!!!

To overcome the inevitable chill you just got reading that last sentence the photo below is of a more balmy place that we can say with certainty was extremely hot at some point due to its volcanic origin. It is not obvious at first glance, but if you look a little closer you can see that the cliff the falls are pouring over is made of columnar basalt. Columnar basalt forms when a thick lava flow cools. As the flow cools, stresses build, and in order to accommodate these stresses cracks form resulting in columns with a polygonal shape. As you can see Milla Milla falls, which are located near Cairns, Queensland, are pouring over a cross section of a lava flow. By the way, the temperature in Cairns tomorrow is 33 degC!!

Milla Milla falls in the Atherton Tablelands, Queensland, Australia. (Photo: Matt Herod)

Zooming in at the Milla Milla falls to see the columnar basalt. (Photo: Matt Herod)

Thanks for reading and stay tuned for lots of a new posts in upcoming weeks!

Cheers and stay toasty my friends!

Matt

Geology Photo of the Week # 16 – Dec 16-22

Matt Herod December 17, 2012

It’s photo of the week time! I hope you’re excited…I am! There has been a lot of consternation in the twitterverse and geoscience community lately about the true identity of the Ediacaran biota, particularly the little guy pictured below. The abstract can be found here. The basic proposal is that the Ediacaran fossils are not marine, but rather are actually lichen.

Dickensonia specimen at the Smithsonian. (Photo: Matt Herod)

Bonus photo of the week. This is the closest I’ll ever get to being in Science….for a long while at least.

Cheers!

Matt

Geology Photo of the Week #15 – Dec 9-15

Matt Herod December 10, 2012

The 15th photo of the week is of an area of natural acid rock drainage (ARD) in Eagle Plains, Yukon. ARD is a phenomenon that most people associate with mine tailings and mine waste. However, it occurs naturally as well since the only criteria that need to be met are a source of oxidized water, such as rain, rocks or minerals that have a high sulphur content, and a very little carbonate in the rocks. Once you have these three things ARD is very possible, and it occurs naturally all over the world. As you can see at this site the ARD is pretty much killing everything in its path. This is no surprise since the water in the area is about pH 1 or 2 and most things cannot survive such a hostile environment.

That said, a lot of research is going into looking at what an survive in such hostile places and how this might relate to extra-terrestrial life.

The Eagle Plains ARD site. (Photo: Matt Herod)

Dr. Lacelle installing some peepers at the Eagle Plains ARD site. (Photo: Matt Herod)

Thanks for reading!

Matt