Time for a guest blog from Mike Rumsey, to tell you all what the Mineralogists got up to on the days they split up from the Palaeontologists.

Having another geological commitment to attend I arrived in the middle of the night a couple of days after everyone else had settled into the Morrocco fieldtrip – a long taxi drive by darkness and a rough couple of hours sleep and then it was off into the field with the other mineralogists. (We split up so the palaeo people and the min people could get as much done as possible). First up was the amazing abandoned mining town of Angil, nestled in a steep valley once mined for its copper and lead content.

Looking over a town in the valley.

Although an incredible vista, the many hundreds of steps leading up to the top of the valley was difficult in the heat and having only had a few hours sleep – it was a real fieldtrip wake-up call! We found some representative material with our local guide and then moved onto the main important task for the day – Mibladen.

The Mibladen area is famous for beautiful bright red crystalline specimens of vanadinite, which are probably the best in the world, and as such Mibladen is well known to most mineralogists and it was great to visit such a famous locality. Vanadinite from here has been known for a long time, but most of the material that ends up in the UK is poorly located and is often just labelled vanadinite from Mibladen, Morocco - this is not really fit for some of the scientific purposes of the museum, so we wanted to collect material directly from a number of different outcrops, mines and workings so we could record exactly where subtly different specimens of vanadinite occurred.

Vanadinite

Another feature of the material that reaches the UK on the commercial market is that it has often been heavily prepared. This might involve cleaning in acids or selective trimming or removal of other less aesthetic mineral species that get in the way of the bright red vanadinite crystals. This is unfortunate as we are losing geologically relevant information when this happens, so I wanted also to obtain some ugly, fresh material that might have all sorts of natural alterations, erosion crusts and associated minerals combined that could tell us or future geologists something a little extra about this place than the readily available specimens.

After a few hours of driving between localities and getting some quick representative samples the day was complete before I knew it, but I had lots of samples and was happy - we met some really interesting people and saw some incredible hand-dug mines and pits in the middle of the desert where prospectors had been searching for vanadinite.

On the second split day from the palaeo guys, we mineralogists visited the area of M’fis and Taouz, M’fis is a famous area for barite specimens and Taouz is another area famous for its vanadinite. Both these places were really out in the middle of the desert and it was very, (very!) hot - a specific locality called the wulfenite vein at M’fis – was so open and exposed, it felt a bit like some horror film where we might have been abandoned in a desert oven.

The hot desert in M'fis

Still we got to it and collected some really interesting specimens from some more off the beaten track spots in M’fis including areas that have never really been written about or documented in any systematic fashion. At the main site of M’fis we picked up some good representative barite specimens and saw some pretty scary mining operations that I’m certain you would not see in the UK.

An example of scary mining operations

At Taouz we didn’t collect much as I had been lucky enough to visit the locality the previous year. However, we did get some nice specimens from the local miners and we got a quick tour inside the mine workings to see some of the vandinite in situ, both of which we documented to better illustrate the geological environment of the finds from my trip to Taouz the year before.

Analysis of the minerals is still ongoing, but it seems successful so far, with a few species being identified and/or documented for the first time at specific localities and in one case, possibly the first documented occurrence in Morocco… and perhaps the first even for the planet, which considering there are only 4800 known minerals is a fairly rare occurrence.

Huge thanks to Mike for writing this so I could share his experiences of Morocco!

The introduction to this trip and day 1 are covered here by Emma Bernard as we're both taking you through our adventures in Morocco.

Friday 20 September started out very sedately, we got into the jeeps and began our 235km drive to Arzou. However, about an hour into the drive we started to smell something terrible. In the rear of the jeep we assumed it was something being burnt somewhere, it was only when we saw the middle jeep pull over we realised different.

Out leapt the passengers from the smoking jeep. Luckily we were near a town with a garage where the driver managed to take the stricken jeep. We all crammed into the remaining two vehicles, with the luggage on the roof rack and continued our drive. The plan upon reaching Arzou was to split the group, with mineralogists going to a volcano and the palaeontologists going to Bakrit to search for sharks teeth. However, just before we got to the volcano we had a quick stop in a cedar forest to visit the monkeys that live there.

The Monkeys near Arzou

As I've never been to a volcano and collected scientific samples, I asked whether or not I would be able to disband from the palaeontologists and go with the mineralogists. Luckily, this request was granted and I was whisked off with Dr Emma Humphries-Williams, Mark Graham (a fellow palaeontological deserter!) and the Ores Curator. Emma was looking for mantle xenoliths as part of her research on understanding how volcanoes form.

Team Mantle Xenolith.

From left to right: Emma Humphries-Williams, Me (Zoe Hughes), Mark Graham and the Ores Curator.

Both groups arrived at the volcano and we had an initial wander about with a quick description of how it had formed. Then back to the jeeps for a field work spread of tinned tuna, the most amazing olives and a traditional Moroccan flatbread (since arriving back to the UK I have been missing these simple but fantastic lunches!)

The quarry dug into the side of the volcano. You can see our jeeps in the distance and some of the group in the centre. The cone itself is off to the right, beyond the edge of the photograph.

The quarry from a different angle. Behind me (I took this photo) is the crater.

This is the crater, constructed from a series of photos. The quarry above is now behind me.

After lunch the rest of the palaeontologists got in their jeeps in order to go to Bakrit to search for sharks teeth. We descended into the quarry next to the volcano. We hunted for xenoliths, with Emma instructing us on which rocks were likely to contain them (the heavy ones). When we had a pile we all took in turns to break them open to (hopefully) reveal the green xenolith inside. There were some small lava flows present that we took samples from for Emma’s research into the volcano.

Mark Graham and me taking some rock samples.

Mantle xenoliths are fragments of rock from deep below the Earth’s surface (up to 70 kilometres deep!). These fragments have been picked up by the magma as it ascends from the mantle. Explosions fragment the surrounding mantle and allow it to be carried in the magma to the Earth’s surface within a matter of days. Emma is interested in these fragments because they tell us about how the magma travels to the Earth’s surface and also where the magma comes from. She does this by using lasers and acid (not together) in the lab to reveal the chemistry of the minerals within the rock.

Most mantle xenoliths are made of olivine, clinopyroxene, orthopyroxene and spinel; garnet can be present depending on the pressure present when the xenolith was extracted from the mantle.

What a mantle xenolith looks like and the minerals it contains. This one was found at the volcano in Arzou on this trip. It has been cut and polished since we returned to the Musuem.

With the xenoliths we found in Morocco, Emma hopes to find out whether or not there are any unusual minerals present which will tell her about any processes that may have changed the mantle composition and therefore may result in volcanoes forming in the area more easily. This is particularly interesting in this area of Morocco as most volcanoes normally form at the edges of tectonic plates, where either the plates are moving apart (like at the mid-Atlantic ridge) or where one plate is colliding with another creating a subduction zone. However Morocco is far from the edge of a tectonic plate (The closest active one is the mid-Atlantic ridge or the East African rift). Emma is using the mantle xenoliths to work out why there are (extinct) volcanoes in Morocco (and Africa as a whole).

The tectonic plates outlines in black. The arrow shows the approximate location of the volcano at Arzou and its location at the centre of the plate.

While we were at the volcano it started to rain rather heavily. As my rain coat had been driven off in the jeep with the palaeontologists, I had to use my imagination to keep warm and dry by fashioning a bin bag into a coat.

My high fashion attempt to keep dry in the rain.

When our time at the volcano was drawing to an end, Emma had a final sort through of her samples for the best ones to bring back to the Museum. As each xenolith takes some time to process and they are rather heavy, only really good xenoliths are particularly useful.

Emma happily sorting out her haul of xenoliths.

Off we went to meet the palaeontologists so we could drive to our hotel in convoy for the night in Midelt...

Don't forget to check the Fossil Fish blog and come back here for more as Emma and I are writing about each day in turn. Many, many thanks to Emma Humphries-Williams for helping me to write this post (making sure I got the science of xenoliths correct because it is not my field of expertise) and providing the lovely xenolith images!