Tag Archives: glaciation

North, beyond Shetland: A Daysleeper’s diary

by Tom Bradwell (Day 15: Friday, 04:44) (with some photography by Alex Ingle)

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The last time we ventured into Shetland territory it was in pursuit of far-travelled rocks laid down by the last ice sheet, strewn across hard-to-reach islands – Foula, Papa Stour, Out Skerries, to name just three. Our successful 10 island-tour of Shetland took place in 11 carefully planned days in May last year, when the 6-strong team worked from dawn til dusk to ensure that they didn’t return home empty handed. Those precious rock specimens have since been analysed at Glasgow University; their exposure age is helping to unravel the ice sheet history of Shetland and the surrounding area. This time the Britice-Chrono team are on the high seas, aboard the RRS James Cook, looking for glacial seabed mud and ice sheet imprints along the extreme edge of NW Europe, from the Outer Hebrides to the Norwegian Channel.

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In this part of the UK, in July (at 61.5 degrees N and still within the offshore Exclusive Economic Zone) dusk stretches beyond midnight and the sun reappears before 3 am, after only the briefest of nights. That being said, working on the night shift is still a challenge. The geophysical data collection and seabed coring programme on the James Cook works 24/7. The ship’s crew operate on 4-hr ‘watches’, and the science team are divided into day and night shifts (8am to 8pm) to allow around-the-clock working. Punctual, brief, morning and evening meetings allow seamless handover between shifts, an update on the day’s progress, and an all-important weather forecast for the next 48 hrs. Day and night shifts for the science team are similar in content but different in the details. Apart from the darkness, the cold, the nocturnal fatigue and the daysleeping, we have dinner for breakfast and sometimes breakfast for dinner; which mixes up the body’s normal everyday cycle and turns the daily routine on its head. But after 2 weeks on the night shift, having a roast beef lunch at midnight seems almost normal. Although going to bed when the sun is at its warmest will never feel quite right to me. And the AM vs PM confusion is always there, nagging away.

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As we collect geophysical data, recover seabed samples and describe cores well into the night, the daysleepers perform the same rituals as the nightsleepers but just in a different time zone. We say ‘good morning’ to people instead of ‘goodnight’; we cheerfully get down to work on Wednesday night and carry on into Thursday morning; we relax on deck after some ‘early evening’ exercise; and drink a beer instead of pouring that first cup of coffee. But perhaps my favourite bit is not really ever knowing what day of the week it is. Waking up after a full ‘night’s’ sleep to find it’s still the same day as when you went to bed. Confusing, but curiously liberating!

Anyway, back to the science. Yesterday’s leg of the cruise took us 60 nautical miles (or roughly 111.11 kilometres) north of Muckle Flugga lighthouse, Shetland’s northern tip – a point on the Greenwich meridian still in UK waters but on the same latitude as Narsarsuaq Glaciers in east Greenland and Suduroy in the Faroe Islands. We took 9 seabed cores during a 12 hour transit back towards Shetland, each one penetrating different sediment, and each one hopefully holding its own clues as to when the last ice sheet retreated and when sea levels rose. The spectacular sequence of moraine ridges on the seabed NE of Shetland is unique within the British Isles, both in its unusual shape and the number of landforms preserved. Although we’ve known about the moraine pattern for a while, and what it means for the last ice sheet to cover Shetland and the northern North Sea, the age of these features remains elusive. What we find when we analyse these cores will hopefully help clear things up.

For me, the crucial part of the Britice-Chrono project comes when linking geological evidence onshore and offshore — something that has often proved difficult in the past. As an Earth scientist, interested in glacial processes, the distinction between terrestrial and marine is a blurred and relatively unimportant one. A bit like the difference between morning and evening when working the night shift at this latitude…

A Perfect Core……..

By Margot Saher, Dave Roberts and Rich Chiverrell (Photography by Alex Ingle)

Darkness. A great mass of ice overhead. The eerie rumbling of a large, uncompromising mass, slowly but steadily on the move. Below a thick layer of stiff red sediment, ground off the red bedrock, crushed and churned into a lumpy, sticky blanket of glacial till.

Dark coasts

Dark coasts

What would later be called Cape Wrath was only miles to the south, but there was no cape yet. Just the grinding of slow and unforgiving ice moving north into the North Atlantic. But the times were changing. The sun gained in strength, atmosphere and ocean started to warm and the gigantic ice mass, later to be known as the British-Irish Ice Sheet, was in decline. As its surface melted, more water reached its bed, and it began to slide helplessly over its own sediments. Slowly it thinned, and retreated in the direction of the Scottish mountains with the ocean lapping relentlessly at its edges.

There seemed to be no hope, but the ice sheet made one last bold dash towards the edge of the continental shelf before it faltered. The recently deglaciated seabed and freshly deposited grey ocean sediments were bulldozed and overrun again by ice on the move, and buried once more in a blanket of red till. Linear ridges (moraines) marked the limit of this temporary re-advance. But it was only a death throw; the re-advance didn’t get far. The ice sheet’s days were numbered. The advance stopped, and turned into irreversible retreat.

A geophysical search for the perfect core.......

A geophysical search for the perfect core…….

Against a backdrop of rumbling, calving icebergs, station JC123-048VC slowly became ice free, as the snout of the ice sheet moved back over the site. A cold, shallow sea took its place; first, still close to the snout of the ice sheet, where streams of meltwater rushing into the waiting sea water lay down a blanket of coarse sand. As the ice retreated further, taking the meltwater streams with it, the sea fell silent. Only fine sediments spat out into suspension by the dying ice sheet made it to our site, slowly covering it in a thick, grey blanket.

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The ice sheet sent a final message as the ice margins retreated south towards the land; a message from an iceberg. As it passed, melting, overhead of station JC123-048VC, pebbles slipped from its icy grip. They plummeted into the depths, impacting into the soft fine clay sea bed. As soon as this excitement started it was over, and the pebbles were slowly covered by more of the same grey clay.

With the great weight of the ice gone, the Earth’s crust rose like an ancient giant from its slumbers, pushing the Scottish continental shelf closer to the sea surface. Over time, the waters shallowed, and the seabed currents became stronger. The last vestiges of the glacial seafloor were scoured by contour currents, which deposited the spoils of an energetic coast on the eroded sediment below. Millennia later coarse sand and shell debris formed a layer of several inches thick. And then on Sunday the 12th July 2015 all changed.

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There was an unfamiliar thud, and then the uncanny sensation of a vibrating tube burrowing into the sediment from above. It cut through the sand in a jiffy, passed the pebbles, and into the soft clays. The tube slid through it like a hot knife through butter. No struggle with the coarse sands lain down by meltwater streams either, only slowing on reaching the stiff, red till. It battled its way into it for a meter and a half. Then the friction became too much. The vibrocorer stopped, and then the whole tube, now full of sediment, was pulled back up to the sea surface, and hoisted back up onto the deck of the RRS James Cook, the ship it had come from. Peace returned once again on to the sea floor, at core site VC123-048VC, a few miles north of Cape Wrath, on the northwestern edge of Scotland; a land mass now devoid of ice sheets and glaciers.

The core came on board and was cut into sections, labelled, scanned, and split. Finally, we, the scientists who had planned the project, planned the cruise, sailed all the way from Southampton to Cape Wrath, and waited for the British Geological Survey (BGS) to deliver the core, first laid eyes on the sediment. The story was there: a stiff basal till deposited beneath the ice sheet; fines marking the first incursion of the sea; further glacial till documenting the ice re-advance, meltwater stream sediments deposited in front of the retreating ice margin; the fine clays deposited when the ice began to recede southwards containing drop-stones from the icebergs, and the marine sand of the modern seafloor. That was what we had come for. And this was the 48th core; none of the previous 47 had told the story of the vanishing British ice quite this clearly.

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Hopefully we’ll be getting more cores like this in the coming three weeks of the cruise. We need this story told in every sector of the British-Irish continental shelf. Only then will we have what we set out for: the complete saga of the Last British-Irish Ice Sheet.

Gripped in the jaws of the Minch

By Richard Chiverrell and Tom Bradwell (photography by Alex Ingle)

1292 km, 51 cores, 177m of sediment, not a bad haul

1292 km, 51 cores, 177m of sediment, not a bad haul


We, the science crew of RRS James Cook Cruise JC123, sailed from Southampton Friday 3rd July bound for the last three transects of the NERC funded Consortium Britice-Chrono, our aim is to work out the timing of the last deglaciation of Britain and Ireland. After a quick stop outside the Solent to test the BGS vibrocore we made hast (10 knots) northwards through the North Sea running geophysical surveys for the North Sea sector (Transect 2) as we went, and in the early hours of Monday 6th July we rounded the northern tip of Scotland on schedule for our speedy (19 knots) tide-assisted passage through Pentland Firth between Orkney and the Scottish Mainland onwards to Transect 8 and the delights of the Minch palaeo-Ice Stream extending north from Skye between the Scottish Mainland and the outer Hebrides towards the edge of the continental shelf and the North Atlantic.

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The Minch seaway ~28-25,000 years ago received ice flow from the major fjords in NW Scotland feeding palaeo-ice stream, which extended north and northwest across the continental shelf. This ice stream dominated the northwestern sector of the British Ice Sheet (BIS). The land- and sea-scape probably developed over multiple glacial episodes, but the sea floor landforms and uppermost geology reflect the most recent deglaciation after 25,000 years ago. The aim of Britice-Chrono is to work out the timescale for this deglaciation, and this has involved fieldwork on land, dating outwash deposits on the Isles of Lewis, Skye and on mainland, and glacially eroded bedrock and boulders across the region. The offshore phase of this research has occupied us, so far, for the last seven days and nights, and involved surveying the sea floor for the morphology and the sediments using acoustic sounding techniques, but critically sampling the sea floor sediments. We have two coring systems on board, a percussive vibrating corer that can sample down to 6 m below the sea bed penetrating the tough materials laid down beneath and in front of former glaciers, and a gravity powered piston corer capable of sampling up to 18m in softer sediments. Our aim is to find shells in these glacial sediments to radiocarbon date and work out the timing of deglaciation.

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The success of the efforts for both our cruises relies on the excellent 24 hour work ethic, diligence and company of the cruise team, science crew, BGS and NOC Piston coring teams and the RRS James Cook captain and crew, all of whom do everything they can to help us. The middle 2-3 days of T8 were particularly nerve-wracking as the BGS crew toiled night and day to fix a particularly truculent problem with the vibrocorer, part of the solution to which lay in finding and removing an electrical break in the 1500 metres of cable that winches the BGS vibrocore to and from the sea bed. Thankfully time was spent obtaining important piston cores in the inner Minch and collecting valuable geophysical data, as the BGS team worked around the clock. As ever in Britice chrono’s experience, the BGS team, had everything needed on board to solve the problem, and cheers greeted the announcement of ready to go, and there followed ‘an in at the deep end’ test of the repair in 500-600 metres of water off the continental shelf fronting the Minch ice stream. Success, with 4.14 metres of glacimarine muds recovered, and on leaving the waters of T8 a further 11 vibrocores were recovered containing the key shell-rich glacimarine and subglacial muds our project requires.
Calm seas, epic sunsets

Calm seas, epic sunsets


Looking back on the Minch experience, it is certainly one of the prettiest (former) ice streams we have worked on during the Britice-Chrono cruises, with land in view and visiting the Inner Hebrides passing the Isles of Skye, Lewis/Harris and Raasay amongst others. The leg has been a considerable success, we have collected 1292.6 km of geophysical data (multi-beam and sub bottom profiler), 51 sediment cores (39 vibrocores, 12 piston cores) and 177.2m in vertical sediment profile; who said the Minch was a small ice stream? Our travels have taken us from Raasay Sound in the south over the edge of the continental shelf at 59° 15’ N, and into near shore waters fronting Cape Wrath and the Summer Isles. The answers to the Britice-Chrono geochronological questions must wait on many months of laboratory analysis, but we leave the Minch with all teething troubles behind us, and a growing bounty of cores in the locker. We are ready for the delights of Shetland…!
A 12m piston core (Tom Bradwell for scale ~ 1.74m)

A 12m piston core (Tom Bradwell for scale ~ 1.74m)

No rest for the wicked: T3 marine sector rumbles into life…..

By Richard Chiverrell

Sites and surveys for transect 3

Sites and surveys for transect 3

Leaving the Celtic Sea and the delights of the Celtic Deep, noon on Sunday 27th July, the Royal Research Ship (RRS) James Cook homed in on Britice-Chrono Transect 3 and the delights of the Irish Sea. For me work levels already high increased, with Transect leader duties to fulfil, and the challenges of finding till – glacimarine mud contacts throughout the sector, and do not forget the shells/fossils for the critical dating targets. That said without Katrien’s (van Landeghem) constant input and support it would have been ridiculous, the work in advance of the cruise identifying targets and new locations drew on considerable effort and collaboration focused on this marine sector of T3 over the past 2-3 years. The success of the efforts for T3 obviously relied on the excellent work effort, diligence and company of the cruise team, science crew, BGS and NOC Piston coring teams and the RRS James Cook captain and crew, all whom did everything they could to help us. Not singling people out, but I thank Katrien for constant input, advice and support as co-leader on this transect and Colm as Science Lead on JC106 cruise.

In the Celtic Sea, the ship was home to the friendly academic interplay between James and Daniel, the Irish Sea also offered up a number of longer standing and perhaps more vociferous historical debates! Understanding and interpretation of the nature and extent of glacimarine conditions in the Irish Sea basin has ebbed and flowed for 4-5 decades, with some proponents holding for a full glacimarine ice margin, others subaqueous margins with more restricted access to the ocean and the other end member glacilacustrine basins separated from the sea. For all these views a comprehensive borehole and geophysical survey targeting environments across the sea floor had the potential to advance understanding, but for Britice-Chrono we clearly needed glacimarine conditions and sediments to provide the marine shells and microorganisms that we can radiocarbon date to gain a chronology for retreat of ice from the basin. Marine fossils have been recovered from coastal glacigenic sediment sequences surrounding the Irish Sea for centuries, but debate continues over whether they are in situ or derived, eroded from the sea floor, during ice advance and then redeposited in glacial sediment. If in situ they offer the potential to constrain retreat of ice margins and the development of glacimarine conditions, if derived they cannot really advance our dating control. Some challenging fieldwork and some painstaking analysis of the fossils and microfossils lies ahead.

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Our journey from the Celtic Deep ~ 51°25’N to our first survey and core sites west of Anglesey around 53°15’N took just over 12 hours at a steady ~10 knots. Our first sites, a bit of a late addition and product of general brain-storming, were ~ 13-14 miles west of Holyhead and targeted the deep waters of northern extensions of St Georges Channel. The location kind of bridges T4 and T3, and we wanted some indication of deglaciation of the deep waters between Holyhead and Dublin. On reflection I was not sure what to expect here, but we had planned a sub-bottom profiler SBP and multibeam survey line as an initial exploration, but circumstances and our temperamental SBP conspired against us. The multibeam data on the other hand were excellent, it was a decent trough 2 miles wide 30-40m deep and we used the multibeam to avoid surface sand waves. Our aims were to avoid surface sand and access the underlying laminated glacimarine units, 2.5 hours and two vibrocores later, some success >3m of mud ending in reddish (an Irish Sea glacial signature!) stiff muds. These laminated or bedded sediments hopefully were lain down under marine conditions fronting the ice sheet as the ice margin retreated to higher ground east and north between Anglesey and the Isle of Man.

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From noon 28th July we moved east and north between the Isle of Man and North Wales, and into a region a large part for me where my interest in this research started, working for and collaborating with Geoff Thomas on sections and sediment all around the Irish Sea. In the deeper waters between the Isle of Man and North Wales, our multibeam data gave us a view onto a very well preserved glacial landscape of drumlins and flutes, moulded elongate low hills shaped by the passage of ice. Uncovered as ice melted and then preserved beneath water probably ever since, their summits are grooved with markings probably formed by ice-bergs calving from and then grounding on the landform surface fronting this glacier. Guided by the multibeam sea floor topography and our shallow geophysical data we targeted hollows in the landscape with shallow fills of sediment overlying the glacial surface. Our vibrocorer can penetrate to ~5-6m depending on the sediments, absence of large cobbles or bedrock, heavy seas and luck. Fingers were regularly crossed and the only wooden items in the all metal BGS vibrocorer cabin are now getting quite worn by us touching them for luck and the right sediments. Broadly we divided the Irish Sea basin into four sub areas, 1. South of a line between the Isle of Man and Barrow-in-Furness completed by 21.30 on 30th July, the deeper waters between the Isle of Man and western Cumbria by 18.30 on 31st July, the Solway Firth (between the Isle of Man and Scotland) by 5am 1st August and finally the deep waters west of the Isle of Man by 11.30am 1st August. >500km of survey line, 34 cores in total, almost all of them reaching the reddish glacimarine muds often laminated some with dropstones and in many cores stiff diamicts with clasts typical in character of Irish Sea glacial tills seen in coastal cliff sections around the basin. We had the sediment contexts we desired, the subglacial to ‘glacimarine’ transition and water-lain ice marginal muds from settings across the transect. The nature of this water-body and answers to the Britice-Chrono geochronological questions must wait on many months of laboratory analysis, but I left the Irish Sea northwards for the Malin Sea and T7, satisfied and with the feeling that the sediments and geophysics alone will fill in a significant and long standing gap in our understanding of the last glaciation of the Irish Sea.

The raging waters of the Irish Sea

The raging waters of the Irish Sea

Many a mickle makes a Muckle (Roe)….

Contributed by Tom Bradwell (1.75m tall) and Rich Chiverrell

Dawn broke at 0430 (we understand but not by experience) with clear skies and wide views across the hills around Lerwick. The team assembled slightly later than this, well 4 hours later actually – at around 0830 – after a good night’s sleep following our 2-day extravaganza on Unst. The prospect of great weather called for a slight change of plan and we decided to split into 3 teams for the day: Derek, David & Tom headed west in the Hilux to hopefully find some nice big rocks on Muckle Roe; Rich and Matt went south in the Vito MPV in search of glacial sands; and Chris, Saskia and Vince went to gather more footage of the Project Leader in his well worn and very practical Drizabone field gear.

The island of Muckle Roe lies in St Magnus Bay but is only 25 m from the Shetland mainland at its closest point and is conveniently joined by a sturdy bridge spanning Roe Sound. Taking advantage of this team Hilux drove to the end of the public road at Muckle Ayre, parked and set off on foot into a chill NW wind towards the furthest tip of the island. Muckle Roe is composed almost entirely of Silurian/Devonian granite and is quite rightly a national scenic area. The landscape is quite different to that across much of Mainland Shetland, with distinctive red granite crags, precipitous cliffs, and an abundance of glacially transported boulders – so many boulders in fact that it soon became apparent that the cosmogenic sampling team were in for a good day! After a couple of kilometres walk they found the first signs that glaciers had once crossed the island from east to west, with a number of rounded ultramafic and meta-sandstone boulders scattered across glacially polished and broken bedrock surfaces. These boulders could only have come from the Shetland mainland and their presence was a clear indicator that a large ice mass covered the whole island group probably with a 30-km wide ice lobe flowing into St Magnus Bay. Unfortunately, these boulders in particular could not be sampled as they don’t contain quartz: the mineral needed for the cosmogenic nuclide analyses. Instead the team took quartz-rich granite samples from a glacially deposited boulder, a smaller cobble and some ice-worn bedrock. If only all sample sites were this good!

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The team enjoyed a brief lunch stop of cornish pasty, squashed sandwiches, dried mango and caramel logs sat on glacially polished granite slabs overlooking the western cliffs with fine views to Foula and Eshaness. Derek even found the time and signal strength to send a couple of tweets. More sampling followed in the afternoon including a very prominent granite erratic nicknamed simply “big white” taking the final tally to 9 for the day. As the sun beat down, and temperatures soared into the low teens the weary 3 made their way back to the Hilux via the coastal path taking in some of Shetland’s (if not some of the UK’s) best cliff scenery. Vertiginous granite cliffs at Picts Ness and the Hole of Hellier were carefully navigated around before the samples were safely deposited in the truck.

Team ‘Elusive Quaternary Sediment’ following up some precise instructions from T1 Leader of go to behind ‘a well-known supermarket chain store’ there will be something there, and failing that drive around and find some stuff…… Pausing for some quick digital recognisance, emergency lunch supplies and then the section- bedrock and 1-1.5m diamict, job well done part one at least. The driving around aimlessly took much much longer! The coastal sections on the journey down to Hoswick proved equivalently disappointing, though interesting if you like windblown sand and peats inter-bedded of Holocene age overlying a thin glacial diamict. Matt and I then headed for Burn of Mail, and an eventual rendezvous with ‘the making of….’ documentary team. A cracking valley and showing the first set of convincing retreat moraines with ice flow down the valley eastwards from the mainland of Shetland. No sections but cracking geomorphology and a good boulder spread with the potential to record passage of the ice margin on land from the east. There was the tremendous opportunity to watch a future movie star in the making, as our film and outreach crew (Vince and Saskia) collected some of the final footage on Shetland for the U-rated comedy prequel to ‘Silence of the Lambs’. We then headed west to check out the southern flanks of Papa Sound, a stretch of marine waters extending from our destination on Wednesday ‘Papa Stour’ to the hinterland of ice on Shetland around Voe. Our brief ‘brief’ was to find boulder and if possible OSL datable materials, lo and behold we did, much of the lower terrain between Voe and Aith was ornamented with moraine ridges and glacial sediment documenting in this case the retreat of ice margins from the west onto Shetland. 15 m off the road inland of Gon Firth a 5m thick borrow-pit section through a moraine shows a sequence of a coarse grained boulder (>1 m) diamict overlain by a finer grained (>0.3m) poorly stratified till, but separated by 0.5m of stratified outwash sands probably lain down as wash down the front of the moraine. OSL samples were recovered and have the potential to add to the age control in this sector of the former ice sheet, particularly with paired cosmogenic ages if possible.

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C3W team Vince and Saskia departed for home this afternoon, overloaded we know with excellent footage documenting the work of Britice-Chrono and the T1 team on Shetland, we thank them for their company, hard work and efforts, and wish them a speedy journey home…. A fine evening meal (cooked by chef Fabel) of Jalfrezi chicken with rice, poppadoms and indian snack selection was enhanced further with David’s home-made onion pickle accompaniment (recipe available on request). With ready made plans for tomorrow and Papa Stour hopefully on Wednesday, Transect 1 (onshore) feels like it is rounding the bend onto the home straight…..

Out Skerries, the eastern edge of Shetland.

A boiled egg and toast to start the day, excellent, the only downside was the time 5.30 am which hurt slightly! That said Day 4 on Shetland was pretty special. Our numbers had swelled to 8 with the arrival yesterday of BriticeChrono P-I Chris Clark and C3W Outreach Team Vince Jones and Saskia Pagella.  We set off for the ferry to Out Skerries at 6 am. The first of two ferries departed Laxo at 7.10am and sailed to Whalsay, where we caught a second ferry to the dock in Bruray on Out Skerries, the easternmost islands of Shetland around half nine. Slightly cloudy start, but that quickly changed to glorious sunshine and the views from this inhabited collection of rocks in the north North Sea were absolutely stunning.

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The BriticeChrono T1 Team are on Shetland to try and constrain the timing of retreat of ice from the last glacial maximum in this sector of the last British Irish Ice Sheet (BIIS). Running in parallel to this land-based research will be a marine cruise examining the landforms and sediments preserved on the sea floor around Shetland scheduled for July 2015. Our task for 12-13 days is to sample boulders and sediments that will allow us to work out the timing of ice retreat across Shetland. From the distribution of these ages we intend to work out the pattern and directions of ice retreat. So far (see our previous blogs) we have sampled the far south of mainland (day 1), Foula in the south west (day 2), the northwest tip of Mainland; North Maven (day 3) and, today it was the turn of the east and Out Skerries. We are building a grid like pattern of dating sites across the islands aiming to get as far North, South, West and East as we can.

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From the dock on Bruray we walked across the bridge to Housay (the western island) to the end of the road and then onwards to a boulder strewn low (~28m high) hill. Here the bedrock displays clear signs of subglacial streamlining, with striae (scratches made by glaciers) and block removal on roche moutonnee showing ice flow to the northeast. The team split up slightly with Vince and Saskia collecting footage of all the action and interviews with Chris (Project P-I) and Tom (Transect Leader). Derek, David and Matt kept their eyes on the ball, or round boulders to be specific.  Some nice round-ish and very tough granodiorite boulders needed action from the rock saw (once the batteries had been recovered)! The granodiorite boulders lie on schist bedrock (containing quartz veins also sampled for cosmogenic nuclide or surface exposure dating) and these were probably carried to the island from mainland by the ice. Glacial transport was confirmed by an interesting exposure of glacigenic sediments, which showed striated bedrock covered by ~2m of till also containing examples of the granodiorite boulders and a pronounced macrofabric.

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Delighted with our endeavours in the west we headed to the eastern end of the island for a lunch with a view and more boulder sampling, two pegmatite and one granodiorite. This left a very satisfied team to adjoin to the village shop once abandoned by academic moth (Bradwell) who continued his exploration of bright lights: boulders, tills and scenery providing informative updates by walkie-talkie. Both activities provided important sustenance and rest before the ferry back to mainland.

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Transect 1 Shetland – Day 3: Northmaven

By Derek Fabel

The writing is in the sand

The writing is in the sand

After a leisurely start we were on the road 8:45 to North Maven, the northern most part of Shetland Mainland. The target areas for sampling were a very distinct set of bedrock ridges extending for several kilometres in a northwest direction on the west coast of North Roe. We had spotted the bedrock ridges on air photos and satellite images, but now it was time to set foot on them. Tom, David and I drove to the end of a 4×4 track, shouldered our packs and set off looking for the ridges. After strolling through 3km of rocks, heather and bogs we were standing on what we previously had only seen on a computer screen. The shapes of the ridges, and smooth bedrock features on them, show they have been covered by flowing ice. When the ice melted away it left behind boulders that had been carried by the moving ice to the area. The boulders are of different rock types and thus were eroded from different source areas. The boulders are what we were after, and we quickly collected samples from the tops of six of them.

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While we were sampling boulders, Matt and Richard, the sedimentologists in the team, went along the Esha Ness coast looking for sedimentary deposits related to the last ice sheet that covered Shetland. In the afternoon the two groups met up in North Roe and did a vehicle swap so Matt, Richard and Tom could visit a famous Quaternary site at Fugla Ness at the northwestern tip of Northmaven. Fugla Ness was a stunning location, with a well exposed interglacial peat deposit between two glacial tills, apparently 130,000 years old and containing roots and stumps of Pine trees. For Tom, Matt and Rich the most exciting new (?) finds were a set of striations in the gabbro bedrock and these were buried by the Fugla Ness interglacial deposits and so are at least 130,000 years old and testify to previous glaciation of Shetland.

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David and I went north towards Fethaland, to look for some more rocks. After collecting three more samples, we looked at some glacial moraines near Skelberry, and promptly collected another three samples from some large, very, very, very hard granitic boulders. It was now 7pm and we were supposed to meet Chris, Vince and Saskia, who had flown in from England today, at Frankie’s fish and chip shop (the most northern chippy in the UK) in Brae. They were duly seated munching on fish and chips. Unfortunately Tom, Matt and Richard did not get back in time for a sit in meal. They enjoyed their fish suppers at Mavis Grind while the sun was setting.

Well worth the rushing and much deserved

Well worth the rushing and much deserved

Another long and very productive day, done. Out Skerries tomorrow.