GeologyRocks

GrGeGbGh#1

OK, (hopefully) an easy one to start. Remember I need the location and the geological feature.

A hint is to look at the compass arrow. The image is slightly oblique. Click on here for a larger version.

Must be:
Location: The Great Glen (Fort William end)
Feature: The Great Glen Fault (strike-slip fault)
I reckon.

Congratulations Matt on winning the first ever geology rocks geology hunt!

That was far too fast! Time to slow things down with a more tricky one but with a bit of geological knowledge there are some clues.

A higher resolution image is available here. The image is taken straight down but is zoomed in quite tightly.

Remember I need a location and the geological feature.

I'm thinking an angular unconformity? Had guessed Siccar Point, but North's the wrong direction for that...

It's not Siccar Point (sticking my neck out there) as there's no beach there. No idea where it is though....

BTW: Excellent idea, Hypocentre!!

Angular unconformity is correct.

It's not Siccar Point - Google Earth's coverage is really poor there - I did have a look.

Perhaps you should be providing more clues. No one seems to be getting it. 

I think I might let this drag out a little longer as finding good examples to use is not that easy and although I do have a few others up my sleeve I don't want to waste them too quickly.

There are a few clues in the image

• We've established that it is an angular unconformity
• We have some near horizontal red rocks overlying steeper, folded darker ones
• We are on a south facing coast somewhere in the British Isles
• We are in an area of reasonably high resolution Google Earth coverage

There aren't that many candidates ...

Start Point?

Not Start Point.

I'll keep this one running and put up another easier one in a short while.

GrGeGbGh#3

As people seem to be finding #2 tricky I'll leave it open for a bit and give you an easier one for this week

The image is slightly oblique and remember to look at the compass arrow

Remember I need both the location AND the geological [and in this case geomorphological as well] feature.

Click on here for a larger version.

Arthur's Seat, Edinburgh

Remains of a volcanic plug

(Great idea for a quiz!)

We have a winner. Congratulations Spinney.

It is indeed Arthur's Seat in Edinburgh. The central part is a volcanic plug with the teschenite (gabbro) sill of Salisbury Crags to the North.

The geomorphological feature is a 'Crag and Tail'. Arthur's Seat forms the glacially eroded crag on the upstream side and the tail of deposition of glacial debris on the downstream side can be made out in the upper part of the image.

Clues in the image were a probable massive igneous intrusion close to a centre of population. An easterly ice flow direction from the Crag and Tail would generally limit you to Eastern Scotland.

Next image up soon, but in the mean time GrGeGbGh #2 is still unsolved. It is a bit more difficult but I don't want to sully this one with more clues just yet.

GrGeGbGh#4

OK, for this week another classic area of British geology

The image is taken vertically and remember to look at the compass arrow.

For newcomers, I need both the location AND the geological feature.

Click here for a larger version.

Previously solved locations can be viewed in Google Earth from this KMZ file.

It's the K-T boundary at Alum Bay on the Isle of Wight. The Tertiary deposits are the famous coloured sands, often seen in Isle of Wight souvenirs. 

It is indeed the Cretaceous-Cenozoic boundary at Alum Bay on the Isle of Wight (are we allowed to call it K-T any more now that the Tertiary no longer exists officially?).

In the right of the image is the Upper Cretaceous (Campanian) Chalk close to the Needles. On the left are the Cenozoic (Lutetian) Bracklesham Group clays sands and lignites, the coloured sands used in IoW souvenirs. In the centre of the image are the Lower Cenozoic (Thanetian) Reading Formation and (Ypresian) London Clay.

Geological clues in the image are a Chalk boundary on a north-west coast close to vertical beds (straight outcrop boundaries down cliff).

Reminder #2 is still unsolved. Another image later if I have time.

GrGeGbGh#5

Since Alum Bay was solved so quickly by Duncan here is another image.

The image is taken obliquely and I've included the scale bar

For newcomers, I need both the location AND the geological feature. (I'd like the precise location for this one please)

Click here for a larger version.

Previously solved locations can be viewed in Google Earth from this KMZ file.

Mile Fort just west of Housesteads Roman Fort on Hadrian's wall

55 deg 00: 44.62 N, 2 deg 20:15.61 W

Outcrop of Whin Sill, upon which a lot of the roman wall was built - dolerite sill underlying a lot of the North Pennines.

(Sorry this one didn't last long - but I was there on a geology trip a couple of years ago so it looked familiar! I was also in the middle of looking up stuff on the Whin Sill for some teaching materials I am writing - how's that for a co-incidence! Now I really must get some work done!)

Yes, it is the Whin Sill at Milecastle 37 just west of Housesteads Roman Fort on Hadrian's wall.

That's your lot for now but #2 is still unsolved.

If anyone has any good locations to use for future geology hunts please e-mail me via the icon on the left.

GrGeGbGh#6

From a suggestion from Spinney (who obviously is barred from this one) here is a subtle one but again a famous area of British geology. There are several geological/geomorphological features here (some more obvious than others) but hopefully should combine to give the solution.

As it is subtle, the image is straight down and North is up.

For newcomers, I need both the location AND the geological/geomorphological features.

Click here for a larger version. (You'll probably need it for this one)

Previously solved locations can be viewed in Google Earth from this KMZ file.

Good point! I've asked the BGS what they think, will let you know what they say. 

Thats just south of Malham Tarn, N. Yorks. where the Horton formation (silurian) is exposed to provide an impermeable basement for the tarn. The stream dissapears underground when it flows onto the limestone, meaning all we see is that marshy area.

Just south of Malham Tarn is correct. Well done Matt.

Malham Tarn is just visible at the top of the image. As Matt says, the tarn in on the impermeable Silurian (Lr. Ludlow) Horton Formation siltstones. As the river crosses the Craven Fault onto the Lower Carboniferous (Visean) limestones it disappears underground at Malham Sinks to reappear at Airehead Springs south of Malham village (not a Malham Cove as once thought).

The line of the Craven Fault can just be made out as an east-west feature as the northerly extent of the sink holes along the line of the road in the east and in the green field to the west of the image.

GrGeGbGh#7

Definitely my last one for the week!

The image is straight down, remember to check the north arrow.

For newcomers, I need both the location AND the geological/geomorphological features.

Click here for a larger version.

Previously solved locations can be viewed in Google Earth from this KMZ file.

GrGeGbGh#2 Redux

As GrGeGbGh#2 has remained unsolved I'll give you a widerer view and hopefully more of a clue.

The image is straight down and north is up.

Here is a reminder of the clues in the image

• We've established that it is an angular unconformity
• We have some near horizontal red rocks overlying steeper, folded darker ones
• We are on a south facing coast somewhere in the British Isles
• We are in an area of reasonably high resolution Google Earth coverage

For newcomers, I need both the location AND the geological/geomorphological features.

Click here for a larger version.

Previously solved locations can be viewed in Google Earth from this KMZ file.

#7 also remains unsolved from last week

GrGeGbGh#8

Whilst people seem to be struggling with #2 and #7 I thought I'd give you another UK classic locality as an 'easy' one.

This locality, and the Whin Sill, are the only two so far that I've never actually been to. Apparently, this is worth seeing ... but not worth going to see.

I'm going to invoke what WoGE calls the Schott Rule. If you have won GrGeGbGh before then you have to wait the number of hours that you have wins before you answer to give newcomers a chance (i.e. Duncan 1 hour; Matt & Spinney 2 hours)

For newcomers, I need both the location AND the geological/geomorphological features.

Click here for a larger version.

Previously solved locations can be viewed in Google Earth from this KMZ file.

Edit:

1. I didn't know that it looked like this from the air

2.The bit about being worth seeing is a clue

3.There is another subtle clue to the general whereabouts in the text

No.2 is Sulley island, S.Wales. It's an angular unconformity between Carboniferous limestone and Triassic Conglomerates.

Matt's got it at last.

I said that I didn't want to sully it with a clue but obviously I did!.

It is Sully Island, between Barry and Penarth, south of Cardiff in South Wales. It exhibits near horizontal Triassic sandstones unconformably overlying folded Carboniferous limestones.

The island has a causeway exposed about three hours either side of low tide - an international sedimentology conference fieldtrip go marooned there once by the incoming tide (which is very fast round here) and had to be rescued by lifeboat.

The earthworks associated with a Saxon fort can also be seen in both images.

GrGeGbGh#7 and GrGeGbGh#8 are still unsolved

#8 is the Giant's Causeway in Northern Ireland - columnar basalt.

I went to see this last year - the photos you see of it make it look far bigger and more impressive than it is in real life (so it is worth seeing if you are there, but not worth making a special trip to see...). However a cliff walk nearby is worth doing - you get a good view of later flows in the cliffs - with layers of columnar and 'ordinary' basalt. 

Spinney catches Matt up on three solutions each with #7 still in play.

It is indeed the Giant's Causeway where the columnar basalts of the Paleogene Antrim plateau lavas meet the sea. It is the middle of the three lava flows that makes up the rocks of the causeway.

It was Samuel Johnson who replied to Boswell' s enquiry "Is not the Giant's-Causeway worth seeing?" with "Worth seeing, yes; but not worth going to see."