Accretionary Wedge #42 : Countertop Geology

On a brief parole from grading gaol …

Ian Saginor over at Volcanoclast is hosting this month’s accretionary wedge on the topic of countertop geology. As with many wedges, the geoblogosphere has largely decided to ignore, well at least modify, the brief (probably because we mostly have laminate counter tops). Fortunately, Ian has kindly expanded the topic to include any rocks ‘as long as they’re decorative and completely detached from their origin’.

Unusually for me, my example is a palaeontological offering. This is the centrepiece in the foyer of the wonderfully named Hotel Kasbah Meteorites, in Southern Morocco.

The hotel / kasbah is close to the Berber town of Alnif, famous for it’s trilobite fossils. The hills around Alnif Djbel Issimour are called the trilobites mountains and trilobite sellers line the roads like fruit sellers do in other countries. The hotel owners decided to go with the geology motif with highly fossiliferous bathroom surrounds (edit: see below) and this centrepiece of large ammonites and orthocones.

I have a traditional Berber scarf from the rack in the background that I sometimes wear, much to the befuddlement / amusement of my students in the field.

[update:]

The ammonites and orthocones also appeared as a drinks table in a hotel in Ouarzazate that we stayed in on the last night.

Returns to grading gaol …

Rock366

I must be mad. In 2010 I misguidedly decided to photograph a rock on each day of the year and project Rock365 was born. And 365 days and photographs later I managed it. It took me a whole year to recover.

So, how to better Rock365? The answer is to wait for a leap year and launch Rock366, the project to photograph a rock on each day of 2012. Now, this is going to present a few challenges like I’m going on a cruise this summer to celebrate the big five-oh, but I’ve managed similar things before.

For the past fortnight I have been out walking and recuperating from the autumn semester’s teaching in the Lake District of northwest England. The first images therefore are from here.

Day 1 : The Buttermere and Ennerdale Granophyre

This the the Buttermere and Ennerdale Granophyre – a granophyric microgranite from the shores of Buttermere in the Lake District. It was intruded as a laccolith, just over 1 kilometre thick, in the Late Ordovician.

Day 2 : Buttermere Formation Olistostrome

The Lower Ordovician (Tremadocian / Floian [Arenig]) Buttermere Formation is an olistostrome deposit at least 1.5 kilometres thick. The unit, of which this sample is fairly coarse, was believed to have been emplaced as a single massive slumping event in the late Floian. This breccia was found as a loose block in Yewthwaite Comb on the western flank of Catbells in the Newlands Valley.

Day 3 : Sphalerite in vein quartz

This is a sample collected on the previous day from the mine spoil heaps at Yewthwaite Comb. The Lake District is quite heavily mineralised with Ordovician copper mineralisation along east-west faults and Carboniferous lead-zinc veins trending north-south. The fireplace in the Swinside Inn in the Newlands Valley has large samples of galena and sphalerite rich vein rock built into the surround. I found the sphalerite zinc-ore sample here in the mine dumps on the walk back from the pub.

As a bonus, I have a few more rock photographs taken on my stroll up Catbells.

Buttermere Formation, Catbells Summit

Here is the more typical finer-grained Buttermere Formation on the summit of CatBells, displaying some slump folding.

Quartz vein, Yewthwaite Comb, Cumbria

Back at the mining area, here is some vein quartz and some brecciated wall rock.

If you are interested in following Rock366 the daily posts will be on my posterous blog so as not to clog up this site [RSS feed].

The photographs will also be on my Rock366 flickr set [RSS feed]. The 2010 Rock365 set is here.

I shall also endeavour, like last time, to georeference the rocks using google maps.


View Rock366 in a larger map

Rock365: The Postscript

So, the project to photograph a rock every day for 2010 has finally come to an successful completion. The original idea, foolishly conceived around a camp fire in a Bedouin encampment on the edge of the Sahara desert in Morocco last New Year, became Rock365. It never really was a chore, but there were times around the Dog Days of August that I did wonder if I’d have the energy to finish it. The closer I got to the end, the more paranoid I became about not missing a day. Only once did I forget during daylight hours but my better half’s photographic lights saved the day.

It generally took about half an hour for each photo. The majority of hand specimens were shot using natural daylight, a 100mm macro lens and my Canon 5D camera with up to 30 second exposure time to get a decent depth of field. For cut surfaces I found that smearing hand gel over the surfaces gave a better depth of colour and wasn’t absorbed or evaporate as fast as water did. Some images have had their colours tweaked a bit (like the image above) but I think it works better as an image – it looks like a thin section but actually is just a macro. Images were mostly processed using Aperture. Each image was uploaded to my posterous site, my flickr account and added to my Rock365 google map.

Geotagging the images probably to the most time. Trying to track down mines and quarries was one of the biggest challenges, particularly from specimens from Keele University’s excellent rock and mineral collection which I had to resort to when I ran out of my own specimens. For this I found the resources of Mindat invaluable, with just not only mineral and location information but also occasionally latitude/longitude co-ordinates of the mines. I’ve tried to be a accurate as possible with the locations, but some of them had to be an educated guess. The unknown ones I just put at Keele.

Only twice have I been really stuck, when travelling and had to resort to photographing the stone floors of Gatwick and Casablanca airports with my iPhone. Two days in Birmingham also proved challenging as most of the buildings were brick or concrete/glass. The last ten days, spent on the island of Madeira had to focus on basalt as that is all of which the island is composed.

It helped having mini-themes to concentrate on, such as erratics, staffordshire building stones, mantle rocks and meteorites. This strategy does help you keep ticking over.

I suppose my favorite images have to be the metamorphic and igneous rocks. It was in these areas, along with geophysics, that I specialised in for my geology degree thirty years ago, and they still hold a particular fascination. Note that fossils don’t feature much. I have always maintained that the only good fossil is a strain marker!

Anyway, if you have been following the project, thank you. It has, in retrospect, been fun to do. Yesterday was the first day in over a year that I haven’t taken a single photograph. This was deliberate, to make the break and move on, but it did feel a very strange thing to do. I’ll try and return to ‘proper blogging’ on this site as it has been a bit neglected of late as I have had a lot to do with work and the Rock365 posterous posts took precedence.

Have a happy, prosperous and peaceful 2011 and I’ll leave you with the complete Rock365 google map. Note that there are two ‘pages’ of locations on the map so about half the world coverage is actually on ‘page two’.


View Rock365 in a larger map

Accretionary Wedge 28 : Deskcrop & Rock365 #300

October’s Accretionary Wedge is being hosted by Matt Kuchta at Research at a Snail’s Pace on the topic of deskcrops. The deadline for the wedge is fortuitous as I can get it to coincide with my three hundredth deskcrop this year!

Back at last New Year’s Eve I was sitting with a group of fellow travellers around a camp fire at a Bedouin encampment on the edge of the Sahara Desert in Morocco exchanging new year’s resolutions. I rashly suggested that I would take a photograph of a rock every day in 2010 and Project Rock365 was born. How long ago that seems. It has been a long slog since but I have now made it to day / rock 300.

I have saved today’s rock for day 300 and the accretionary wedge as it is one of my favourite samples which has pride of place in my home collection. It is a pegmatite sample from the Narestø Feldspar Quarry, Flosta Island, Arendal, Aust-Agder, Norway. The rock contains some really large feldspar and biotite crystals. Unfortunately, I can’t remember but else about the rock and google is not providing me with much help.

The pegmatite was collected on the Keele Geology foreign fieldcourse to Norway in 1991 (in fact my field guide tells me it was on Friday July 12). The Norway fieldcourse was a long tradition at Keele, now sadly superseded. To keep costs down, the geology department (as it was in those days) had its own tents, folding tables and chairs, cooking equipment and gas stoves. We took the ferry to Bergen and traversed Norway twice, out to Oslo and then back to Stavanger, staying at camp sites along the way. I actually did this fieldcourse twice, once in 1989 and again in 1991. We even took enough tinned food to last a fortnight to keep the cost low as Norway can be expensive, but the same logic didn’t quite work the following year when we went across the Alps and actually took tinned Italian tomatoes back into Italy!

The fieldcourse mainly covered high-grade metamorphic and igneous rocks so I was not that much use of the teaching side apart from the structural mapping at Slemmestad and some of the Caledonian nappe structures at Röldal, my role was much more that of van driver. I did however learn a huge amount from our former mineralogist, George Rowbotham.

Matt asks if we could include a scary dimension to the post. I can’t really think of anything scary except I’ve a sneaking feeling that the sample might be a bit ‘hot’.

All three hundred deskcrop images can be found on my companion posterous blog and at my flickr site.

A google map with links to the geotagged images is embedded below.

View Rock365 in a larger map

Rock365

In a moment of madness I have decided to embark on a flickr 365 project – to take a photograph every day for a year. What else would a geologist take for a theme for such an undertaking but rocks? So project Rock365 was born. I’m now ten days in and beginning to realise the enormity of what I have undertaken. Here are small versions of those first ten …

Rock365 : 01 01 2010 : Ammonites
Rock365 : 02 01 2010 : Sandstone Cairn
Rock365 : 03 01 2010 : Plagiogranite
Rock365 : 04 01 2010 : Blueschist
Rock365 : 05 01 2010 : Rhyolite
Rock365 : 06 01 2010 : Larvikite
Rock365 : 07 01 2010 : Haematite
Rock365 : 08 01 2010 : Chile Saltpeter
Rock365 : 09 01 2010 : Blue John
Rock365 : 10 01 2010 : Sideritic Conglomerate

I’ve decided to put the images on my posterous stream as it is easier to update remotely than this blog. Chris Rowan has kindly added this to his allgeo geoblogosphere feed so you may have seen these already. They can also be found in my Flickr Rock365 set.

Ron Schott is doing something similar over on his Geology Home Companion Blog. Although his images aren’t necessarily being taken on that very day, his daily documentation of outcrops / deskcrops are much more detailed (and prettier) than mine.

I hope you drop by at hypocentre.posterous.com and enjoy a whole year’s worth of rock photos (if I can keep it going that long).