WOGE #267

[reynardo]

Brian had a lovely WOGE #266 of the Bikini Atoll, focusing on the Castle Bravo hole. As someone who loves Bert the Turtle, I was able to recognise it, and used my enforced 2 hour delay to dig up the geological info on the whole atoll.

Note to my normal LJ friends - please feel free to try this as well if you think you know the location. You'd be surprised at what people recognise.



I've been tempted to use this location for quite a while. You'll notice North isn't shown. Make your own assumptions about where it is :-) I've been good with the scale, though.

Click on the picture for the larger version on Flickr, but then come back here for the comments, please.

There are three "Where on Google Earth" games running - Geographical, Archaeological and this Geological one. This is now WOGE(Geological) #267. The rules for this one are here. Quite simply, identify this place (Long and Lat) and give a summary of the geological significance, in the comments on this Livejournal. You should be able to sign in with Open ID, but if not, just leave your name in the comment.

Schott Rule is invoked again with this one. Basically, for every one of these you've won already, you have to wait an hour. What a perfect time to do more in-depth research! GMT is 22:00:00 on Feb 7 2011, New York time is 17:00:00 and in Melbourne it's 09:00:00 on the 8th.

Comments

[http://www.google.com/profiles/Atwasi (from livejournal.com)]

33°10' S
150°14' E

Newnes, NSW, Australia

I kinda feel bad about solving one that has been out there for just a few hours... but this place looked immediately familiar, I just couldn't resist. Please forgive me!

Oh, the geology. Were are looking at an extended part of the Blue Mountains range, which is basically a two-level sandstone plateau, cut by gorges. Newnes in particular was once a mining site for oil shale around 1900. So there is also some history here. I am somewhat intrigued by the grid pattern on the sandstone top, not sure how that is formed.

And the prize goes to the early-rising Hamburger with the blue anorak.

[reynardo.livejournal.com]

I really am going to have to find something more obscure next time. And I'd be the last one to complain about fast posting - I had picked the previous one only 30 minutes after it was posted, and had to sit and chew my nails (and look up facts) for the next hour and a half.

I chose this because I lived in the Blue Mountains for a while, and because of the ongoing debate on whether to build a tunnel under the mountains and a second Sydney airport at Newnes (among other places).

Why so familiar to you? Or is it the oil shale?

From personal observation (so the conclusion may be wrong), the grid marks are caused by erosion of the thinner layers of sandstone in a shelf pattern, (often due to tiny layers of shale weakening the sandstone). This picture shows what happens to the layers when there's a valley - the underneath of the shelf erodes away until the top weakens and it comes crashing down. On the tops, it means you get these great wide plateaus with a set of steps down to a stunning view.

Two things to be very careful of:

1) You can't tell if the part you're walking on near the edge has a nice solid base or is only about 6 inches thick and about to fall off. There are fences around the tourist places, and warnings not to go too close to the edge. There are reasons for that.

2) All through the Sydney Sandstone, you'll get these flat wide "bush rocks" lying on the ground on the plateaus and through the bush. Unless you are a trained herptologist and wearing thick gloves, never lift them up or put your hand under them. Our wonderful poisonous wildlife loves living in the shade and cool they provide, and between the funnel webs, the brown snakes and the taipans, it would be a bad idea.

Regarding the oil shale, I'd love if you could comment more.

The Sandstone: BORING. Ok, slight overstatement, but you try being interested in geology when that's 99% of the rocks within 100km of your place. Newnes in particular is on the older (Triassic) Narrabeen sandstone, and the oil shale underneath is late Permian Torbanite. Sydney Basin is formed from the Hawkesbury Sandstone and the Narrabeen formations, and the east-dipping incline on the entire basin means that the Blue Mountains heading west from Woodford are the Narrabeen group. The sandstone itself is more than 2km thick in places - go to the Three Sisters (or see the size of the cliffs here) and you can be looking up at an almost-sheer 500m cliff. It does have thin layers of shale through it, which has a) contributed to the undercutting and subsequent shearing and b) makes the soil not quite as barren as the Sydney metropolitan area, most of which is on the Hawkesbury sandstone and like trying to grow things in a bucket of sand.

More seriously, I shouldn't complain. The cross-bedding and incredible depositional patterns one finds in cuttings make driving quite dangerous sometimes :-)

Enough rabbiting. Ole, it's all yours! Looking forward to something amazing from you.

Re: And the prize goes to the early-rising Hamburger with the blue anorak.

[http://www.google.com/profiles/Atwasi (from livejournal.com)]

Thanks for the great background info and apologies for my shoddy explanation (and btw, for my poor English) I tried to look up a few more bits but couldn't find much that seemed particular fascinating. You obviously have a much better knowledge if you have lived there :) I wasn't sure about the Narrabeen, Wikipedia mentions several strata that I thought would fit.

Considering the oil shale, I don't really have any knowledge about that. I just stumpled upon it while looking up Newnes. The place seems to be littered with historic remnants, e.g. trainwrecks, as visible from many user photos uploaded on Google Earth.


For the familiarity: Several years ago, during my obligatory Work&Travel year in Australia (considering the sheer masses of backpackers you encounter on the east cost, you'd think more than half of Europe's 20-year-olds go there) - I spend some time in Katoomba and have the fondest of memories of the place, even encountered 5 different snakes on a single hike! Actually I think it is one of the nicest places in all of Australia, I yearn to go there again some day :)

There is obviously no slowing down the WoGE community. I have a few candidates in the pipeline, that I thought were just too damn hard... but never mind, I'll just go for it. It'll be up 11 PM UTC again, thats in roughly 19 hours if I am not mistaken.

Btw: Early rising? Late sleeping! :D good night

[http://www.google.com/profiles/Atwasi (from livejournal.com)]

WoGE 268 should be up at:
http://www.scienceblogs.de/and-the-water-seems-inviting/2011/02/where-on-google-earth-268.php

btw - no Schott rule this time! No need for Ron to check his calender.