Last Thursday the class (the entire honours class this time, not just Limnology Students [the few, the brave, the mighty]) headed back up to Loch Lomond to the hamlet of Balmaha. This tiny little village sits practically on top of the Highland Border Complex / Boundary Fault, making it our third visit to this Terrane Boundary (the previous being Arran and Stonehaven).

The purpose of the trip was to get us thinking about relationships between Terranes, the evidence for there actually being different Terranes on either side of the fault, and to give us something to think about for our Stratigraphy essay (due in on Monday – yes, I’m procrastinating).

The trip was pretty interesting, if fairly brief. We only really looked at 3 localities; part of the Complex itself, some Upper Devonian ORS Conglomerate and an earlier Lower Devonian ORS Conglomerate. We didn’t go far enough North to cross over onto the Dalradian metasediments.

The Outcrop of the Highland Border Complex consisted of a Serpentinite outcrop in the forest, and some poorly exposed Breccia on the beach, containing clasts of Serpentinite and Gabbro (Cherts, Dolomite, Pillow Lava and Trondjhemite clasts can supposedly be found if you hunt hard enough, but the exposure is poor). If you fancy trying to track this spot down yourself I highly recommend this leaflet [pdf] (location 5), produced by the Strathclyde RIGS group (Part of the Geological Society of Glasgow).

Serpentinite Clast in Breccia

Unfortunately this was the point in the day where the Scottish Winter began to make its presence known. Remember those nice sunny photos last time? It wasn’t like that:

Loch Lomond in the Rain

The first of the two Conglomerate outcrops we looked at on our way south (location 4 in the RIGS leaflet) was the Late Devonian one. It’s a fairly typical ORS Conglomerate, as previously seen on Arran, of mostly metamorphic clasts in a red sandstone matrix. It probably represents an alluvial fan deposit coming off Dalradian Highlands.

ORS Conglomerate outcropping on the Shore

The Second Conglomerate outcrop (1 and 2 on the leaflet) is a younger outcrop. On first glance it appears roughly similar, being part of the ORS unit, however upon closer examination the clasts are of an entirely different origin. We were seeing Quartzites and various igneous clasts rather than the vein quartz and psammites from the Dalradian. A textural difference is noticeable too, these are much rounder than the sub-angular clasts of the first outcrop. This would seem to indicate that in the Lower Devonian the area to the South of the HBF was not in proximity to the Dalradian rocks of the North.

Foreground: Lower Dev. Conglomerate. Background: Lomond North Basin

View Down towards the South Basin

Well that’s it for the Balmaha trip overview! It was a fun and informative trip, made all the more-so by the fact that it was taken by experts on the subject – including Tim Dempster and Brian Bluck.

For further reading on the subject try the (oft-recommended by me) field guide below:
Lawson, J.D. & Weedon, D.S. 1992. Geological Excursions around Glasgow & Girvan. Geological Society of Glasgow.

Edit: Also, the number of google search hits this is getting from what I assume are my classmates working on their essays is brilliantly high.

Our Transport - The Green Blur, and our mascot - Trevor the Trilobite

Once again we were incredibly pushed for time; so much so that we didn’t have time to climb up the Eildons, instead contenting ourselves with a view from afar. However, that didn’t stop us from examining some of the geology of the area. Across the road from where we parked is Bowdenmoor Quarry; a quarried mass of Sanidine-Trachyte in Silurian country rocks which shares its origin with the Eildon Hills themselves. They were all part of the same intermediate-acidic layered lacolith (with one exception, which I’ll get to shortly).

The Quarry (picture by Hazel Scott)

I collected some nice samples of Sanidine-Trachyte here:

Sanidine-trachyte - note the phenocrysts

Since we had to get moving, we headed up the road, but not before snapping some more pics.

The Mid (lacolith) and Little (vent) Hills

The largest hill (left) is a part of the lacolith, consisting of layered sheets of trachyte and felsite (I wish we’d had time to get a bit of the Riebeckite-felsite). The smaller hill on the right (which isn’t usually counted as one of the three Eildon hills) is actually a volcanic vent intruded later. It consists of a central core of basalt and quartz-porphyry as well as some agglomerate.

Before getting in the car to drive across to the west coast (via Dob’s Linn) we couldn’t pass up the opportunity for another photo.

Emma and I in front of the Wester Hill

Behind us is the reservoir (which I think is man-made) and behind that is the Wester Hill – another part of the lacolith.

The Alternative Unconformity

Since it was about 8:30pm we decided not to clamber down to it, as we were losing the light. Instead we climbed over the top to view the classic Siccar Point example of the unconformity.

Hutton's Unconformity

Again, since we were pressed for time and the cliff was in shadow we decided not to climb down and look at it close up. Instead we spent time posing for photos holding the unconformity:

Hutton's UC

Finally we walked back down the way we were supposed to have come up, stopping to look at the helpful sign explaining the whole thing.

Info Board

We then drove back up to Galashiels, and spent the night playing Guitar Hero.

7:42 AM Apr 9th : In the field from 8:30 this morning to avoid the tides. Brutally early start. – RJ

11:09 AM Apr 9th : Tide coming in quickly. Exposures being hidden unfortunately. Finely lam. Sandstones. Found crinoid fossils – HS

10:31 AM Apr 9th : Looking at a very rare palaeo-fulgurite. – RJ

Fossilised Lightning Strike

1:32 PM Apr 9th : Finished early for the day (highly unusual), going for a tour of the brewery and distillery – geologists work hard, and play hard. – RJ

Between the rock outcrops being underwater, horrific weather and being done for the day we all decided a bit of a break was in order. (Inevitably, this was when the weather got better).

3:59 PM Apr 9th : Carlsberg dont do geology field trips, but if they did, it would be Arran ‘09. – HS

Arran Brewery

The fake waterfall at Arran Distillery

The Distillery tour at least mentioned the geology of Arran having an effect on Whisky; so we had some justification for going there rather than working. (Maltman, 2003)

8:25 PM Apr 9th : Completed (rather damp) geological map of Carboniferous rocks around corrie. – RJ

The Carboniferous of Corrie

9:00 PM Apr 9th : Hard at work at 9pm finishing off our geological maps. – RJ

Working downstairs in the Shorehouse

8:19 AM Apr 8th : Up bright(ish) and earlyish, weather was horrendous last night, not much better this morning. – RJ

10:35 AM Apr 8th : Mapping a field today without an os map. Using paces and bearings. Cold but dry – HS

The morning was spent practicing mapping techniques by mapping Dougrie Field, an area with Dalradian Rocks, Old Red Sandstone and a Dolerite Dyke.

12:03 PM Apr 8th : Mapping outcrops on a field using compass clinos, pacing and our wits. – RJ

The light came out quite strange for this photo, but you get the idea.

1:36 PM Apr 8th : Taking a break from mapping for lunch. – RJ

Lunchbreak

2:47 PM Apr 8th : Second mini bus to be stuck in mud. Full day of mapping complete. Field split by ig. Dyke and a fault. Vern won stare off with a rock? – HS

3:47 PM Apr 8th : Hard hats required in bus, very bumpy road! Saw some awesome folds and micro folds in imachar beach. – HS

3:50 PM Apr 8th : Some small folds in Dalradian rocks. – RJ

Some small scale folding

After Imachar we went back to North Glen Sannox and walked across a transect of the Highland Border Group; looking at pillow lavas, agglomerates and black slates along the river bed. Since we were in a bog and the weather was shocking I decided not to risk tweeting from my iPhone.

6:59 PM Apr 8th : Putting on after sun – somehow still got burnt despite heavy rain. (Ginger gene). – RJ

7:11 PM Apr 8th : Back in the flats and cooking dinner now. weather is lovely now, forecast for tomorrow is awful! Corrie tomorrow i think. – HS

As might be rather obvious by now, the weather occupied our minds for most of this trip. Days three and four were probably the worst.

9:15 PM Apr 8th : Completed geological map of Dougrie Field. – RJ

Rough Geological Map of Dougrie Field showing presumed contacts

12:13 AM Apr 9th : Finished writing up notes from today. Lots of interesting structural bits and pieces today. – RJ

I hadn’t realised that I’d been working quite that late.

Some of my notes for the day

8:23 AM Apr 7th : Early morning in Arran. Weather is truly horrendous. Rain sloshing down, time for porridge. – RJ

8:34 AM Apr 7th : Just waking up and I’m sure there will be some sore heads today. weather is pretty awful but should be another fun filled geoliday. – HS

10:07 AM Apr 7th : Fiona has reversed into a ditch. – RJ

I think there were more photos of this event taken than of any rock outcrops.

Whoops...

11:25 AM Apr 7th : Mapping Dalradian psammite along the river. – RJ

North Glen Sannox – a quick stop, we came back here later in the week to look at the Highland Border Complex nearby.

Starting to get very wet out here...

1:59 PM Apr 7th : Coming down from looking at paleogene granite, standing on some dalradian meta-sediments.  – RJ

We walked up from Catacol, heading inland over Dalradian Rocks to the Northern Granite intrusion in the centre of the island.

Note the Quaternary glacial landforms...

Next we headed along to Lochranza.

3:32 PM Apr 7th : Mapping another beach, still looking at Dalradian psammites and pelites. – RJ

Lochranza in the Background

4:51 PM Apr 7th : We’re at Hutton’s Unconformity. It’s not quite as impressive as the one at Siccar point. – RJ

A brilliant geological site of historic import; but I come from the Borders originally and can occasionally be proud of that fact.

6:29 PM Apr 7th : The weather here is AWFUL. – RJ

Awful weather in Brodick

9:50 PM Apr 7th : Finished working for this evening; produced a geological map of the beach east of Lochranza. – RJ

9:27 AM Apr 6th : Day 2 on Brodick beach. Conglomerate with quartz and psammite clasts. Dull weather but nice. – HS

10:02 AM Apr 6th : Counting clasts in conglomerate. Some of them are actually just algae. Heading up to Sannox again in the Arran ‘09 partybus. – RJ

Lots of weathering and organic material can make it quite difficult to identify rocks. But that’s what Hammers are for.

10:55 AM Apr 6th : First to fall in a burn: Emma. – RJ

12:24 PM Apr 6th : Had a nosey round an old barite mine, now off for sedimentary logging. – RJ

(By which I mean me and Hazel just looked in, no health and safety rules were ignored – we promise). This region was the location of a great deal of mining of large Barite veins in Old Red Sandstone rocks.

In the Afternoon we headed back down to the Beach in Sannox Bay, dividing into groups which logged separate stretches of the coast.

2:35 PM Apr 6th : It’s raining but we just found an awesome fault that hasn’t mangled the stuff around it. :) – HS

A very clearly defined fault through the conglomerate we were logging.

Small, clearly defined fault.

2:36 PM Apr 6th : Sedimentary logging [See Photograph] – RJ

Groups logging further down the shore

3:07 PM Apr 6th : Fiona taking a stage dive off an exposed Flow Channel – RJ

Here’s a preserved channel where a fast flowing flash flood cut through the underlying sandstone, depositing conglomerate on top.

Fiona posing for Photographs

Sketch Diagram of the flow channel, demonstrating what’s going on slightly more clearly.

Diagrammatic Representation of Flow Channel

3:47 PM Apr 6th : Vern: if in doubt lick it.  – RJ

I’m sure there was a reason for Vernon licking a deformation band, but I can’t for the life of me remember what it was…

4:11 PM Apr 6th : Looking at deformation bands in Permian sandstones now.  – RJ

Vernon licking a deformation band

8:22 PM Apr 6th : Hard at work graphically logging our beach. We’re working well into the evening tonight. – RJ

9:04 PM Apr 6th : Finished sedimentary log. Next up we do a mini-presentation on it. – RJ

The finished log.

10:21 PM Apr 6th : Long night but has been fun! Learned how to do sedimentary log graphs. Still working away – HS

The Shorehouse (our accommodation for the week)

12:25 AM Apr 5th : Frizbee and instruments packed along with heavy duty waterproofs, lets hope it doesn’t rain too much this week, roll on the fun of Arran 09 – HS

9:04 AM Apr 5th : First quote of the week, ‘”Soil, where rocks go to die” (Vernon). – HS

9:21 AM Apr 5th : Clambered onto the minibus, weather forecast isn’t amazing. – RJ

9:39 AM Apr 5th : Tomayasu Hotei, I’ve got a brand new (electron microscope) and Rammstein as music so far on the arran ‘09 partybus. – RJ

John Faithfull, one of the curators of the Hunterian Museum, has a truly excellent taste in music which kept us entertained for the whole week.

10:09 AM Apr 5th : The weather is glorious today, music has gone from Irish folk, to talking heads to ragtime radiohead covers. – RJ

12:09 PM Apr 5th : Boarded the ferry for Arran. – RJ

12:37 PM Apr 5th : A bit of a fresh wind but great to be back on the sea again. Lovely weather! Emma going to pirate the ferry! – HS

2:46 PM Apr 5th : Heading to Sannox to practice taking dips and strikes. – RJ

3:32 PM Apr 5th : Standing on Sannox beach, cold and sunny. Learning to use a compass clino. Geologists throw rocks apparently. I need gloves. – HS

Some initial practice here to make sure everyone’s doing things right, and to adjust the compasses for magnetic declination.

3:39 PM Apr 5th : Using pacing and stride length to measure distances. – RJ

Stride length was measured here and noted, so that it could be used to estimate distances by pacing later in the week.

4:29 PM Apr 5th : Just finished looking at some terrestrial sandstones and conglomerates, heading to shops. – RJ

A quick stop off to look at some Old Red Sandstone in Sannox Bay.

6:26 PM Apr 5th : The view across the bay is lovely – RJ (Picture below)

Goat Fell viewed from Brodick

7:15 PM Apr 5th : Why are we watching Ghostbusters? Also, we have a lecture in 15 minutes. – RJ

7:46 PM Apr 5th : Listening to a lecture from Vernon about the importance of fieldwork and reports. – RJ

The work throughout the week consisted of Field Work throughout the day (generally 9-5, with variations depending on tides, weather etc), followed by lectures and written work in the evenings (Working from 7 or 8 until we were done, sometimes as late as 11).