The Ramson Cliff erratic: much ado about nothing

The location of the Ramson Cliff erratic -- which was found at about 85m OD but which has now been moved to the lower edge of the field.  Beware -- it is sometimes called the Baggy Point Upper Erratic............

A very strange article has been published in QN167, purporting to demonstrate that the Ramson Cliff erratic is an aberration, having come from the Cornubian aureole of Devon or Cornwall and having nothing to do with the glaciation of the Devon coastline.

A REVIEW OF THE RAMSON CLIFF ERRATIC: EVIDENCE OF HIGH-LEVEL ICE FLOW?
Tim Daw, Rob Ixer and Paul Madgett

Quaternary Newsletter 167, Feb 2026, pp 13-19

https://www.qra.org.uk/quaternary-newsletter/167-6-ramson-cliff-erratic/

I suspect that the prime author is Tim Daw, and that Rob Ixer and Paul Madgett have contributed specific detailed segments of the text or provided information.

It's strange because the article doesn't seem to know what it wants to say.  It strikes me as an article in need of some evidence.   After an introduction flagging up the uniqueness of the boulder (which we might question), the authors describe its location after being moved around a bit by the local farmer, and then they describe its petrography.   This is interesting, and provides us with much more detail than we had before -- but the conclusion (namely that the erratic has probably come from the Cornubian rocks exposed to the south) needs to be treated with caution.  There are at least two reasons for this:  

(a) we would be basing a powerful weight of evidence on one small sliver of rock used for a thin section, representing maybe 0.01%of the bulk of a 700 kg boulder, with a rock type that is notoriously variable. It appears that epidiorites (the rock type in this case) are renowned for being "patchy". Metamorphism is rarely uniform across a large block. A patch in one corner that looks Cornubian doesn't rule out another Scottish-style patch 20 cm away.  There has been no new sampling -- the thin section slide is the same as that examined over 50 years ago.

(b) as far as the provenancing evidence is concerned, there is too much telling and not enough showing.  We don't get to see the slide in question, or those with which it has been compared.  Ixer is effectively telling us to believe what he thinks -- "I'm the expert, and you need to believe what I say to you......"  His evidence is almost entirely subjective visual matching based on decades of experience looking at stones. Some stones.   There are lots of others that he hasn't looked at.  When he says it's a "match" for rocks outcropping on or near Dartmoor, he is making a visual call that a layperson—or even a general geologist—cannot easily verify without access to the same "library" of thousands of thin sections. So scepticism is entirely in order.

Ixer has not definitively proven the absence of Scottish markers in the entire 700 kg mass. If we move beyond "trust me" petrography, researchers might just look for specific indicators to confirm a Scottish (Dalradian) origin.  According to the Dalradian literature we might see:

Zoned garnets or specific biotites: Scottish Dalradian rocks often contain complexly zoned garnets or high-Ti biotites formed during the intense, multi-stage Caledonian Orogeny. In contrast, Cornubian greenstones were altered by a single, later heating event from granite intrusions. If a thin section from the erratic showed these "polyphase" metamorphic crystals, the Cornubian theory would collapse.

High-salinity fluid inclusions: The Scottish Dalradian is "ubiquitous" in high-salinity and volatile-rich fluid inclusions that are characteristic of its specific regional metamorphism. 

Trace element ratios: Geochemical analysis using the ratios of Lanthanum (La), Thorium (Th), and Scandium (Sc) can distinguish between different tectonic origins for basic rocks. A Scottish rock would likely show a different "arc-like" trace element signature compared to the intra-plate signature of South Devon greenstones.

All that having been said, I am profoundly sceptical that you can actually do precise or spot provenancing on anything, since we do not have a detailed or comprehensive knowledge either of the erratics we are seeking to find homes for, or of the geographical occurrences of all possible sources.   

(The problem is exactly the same as that which confronts us at Craig Rhosyfelin, Carn Goedog or any of the other UK locations that are deemed by Ixer and others to be Neolithic monolith quarries.)

Anyway, interesting work which moves us forward, and I am sure we will see more of it!  

Following a rather sterile and futile "history of the stone" which involves a mention of WW2 Luftwaffe air photos (I kid you not), the authors move on to a discussion of other erratics in the Baggy Point - Croyde -Barnstaple area, and say of the erratics in the Fremington deposits: "they are not inconsistent with local areas, such as the Dartmoor Aureole and so are not uncontested evidence of Irish Sea glacial intrusion."  That is an absurd statement, but it is followed by another which destroys any pretence that this is a serious scientific article:  ".......the Ramson Cliff boulder is unique as a claimed example of a high-level glacial erratic in the area; all other documented glacial erratics were found below 30 metres OD."  That is a lie.  There are around 20 other erratics, described by Paul Berry and Paul Madgett in the literature, and even mentioned by Daw in other posts on his blog.  They occur, for example, at altitudes of 45m and 60m.   They are smaller than the Ramson Cliff erratic, and have clearly been moved about since they were found, but they are no less significant than the thousands of small erratic clasts that I have found in the fields and stone walls of Pembrokeshire.  It is just that here lead author Tim Daw chooses to ignore them because they are inconvenient.

From here on it is all downhill, with a discussion of mechanisms by which the Ramson Cliff boulder might have been emplaced.  Once again, the discussion about ice-rafted boulders is spoiled by a complete failure to assess the isostatic - eustatic interactions that might have applied at times when ice-rafting might have operated in the Bristol Channel.  The preference of the authors (or at least two of them!) is for the human transport of the boulder, regardless of the complete lack of evidence that might support that.    It's all very vague, and full of speculations and assertions as substitutes for facts.  The authors round off with this:

"The lack of evidence for uncontested glacial erratics above 30 m OD on the south coast of the Bristol Channel in Somerset and north Devon counsels caution when citing the Ramson Cliff erratic in glacial boundary studies."

In other words, we contest the other erratics or choose to ignore them -- thefore they do not exist.

Oh dear oh dear.......

Lee and Roberson on ice limits

 

The inferred Anglian glacial limit, following Booth et al, 2015.  The line on the south shore of the Bristol Channel is overall rather sensible, but the authors ignore the evidence for glaciation of the whole of the Isles of Scilly and in the Somerset Levels depression.  They pay due respect to the evidence of glaciation in the Fremington area, and the blue line approx as far inland as Bideford is deemed to be supported by hard evidence on the ground,  as suggested by Kidson and Wood back in 1974.

Interpreted late Devensian glacial limit, conjectural (red line) and even more conjectural (yellow line).  The "ice-free enclave" in southern Pembrokeshire is shown here uncritically, even though there is no evidence on the ground to support it.  Some conjectures are repeated so often that people think that they must surely be true, and that somebody, long ago, must have had some evidence, long since forgotten.........

This is a interesting article which synthesises a great deal of material contained in the specialist literature. It's interesting in that it pays virtually no attention to the idea of a Walstonian glaciation (or series of glaciations) in the British Isles, on the grounds that the evidence is too sparse.  So the authors refer to just two big glaciations for which there is abundant evidence on the ground -- the Anglian and the late Devensian.  

The paper is open access, and there is a vast reference list with links.  Very handy.

We are reminded of just how much conjecture there is till in the literature.  

==========

Refining the known extent of major onshore Quaternary glaciation in the UK — Types of evidence, nomenclature and uncertainty
Jonathan R. Lee, Sam Roberson 
Proceedings of the Geologists' Association
Volume 136, Issue 3, June 2025, 101087

https://www.sciencedirect.com/science/article/pii/S0016787824000683#bb0095


See also:

Quaternary Provinces and Domains – a quantitative and qualitative description of British landscape types
Steve Booth , Jon Merritt , James Rose 

Proceedings of the Geologists' Association
Volume 126, Issues 4–5, October 2015, Pages 608-632

https://www.sciencedirect.com/science/article/abs/pii/S0016787815000668

C. Kidson, R. Wood
The Pleistocene stratigraphy of Barnstaple Bay
Proceedings of the Geologists' Association, 85 (1974), p. 223

https://www.sciencedirect.com/science/article/abs/pii/S0016787874800258

and this:  

https://www.qra.org.uk/mp-files/qn158_1_late-devensian-ice-free-corridor-in-pembrokshire.pdf/

Tim Daw's anti-glacial hypothesis

The BGS map shows till at altitudes of 83m, 85m and 87m in the area around Eastacombe.  We have no reason to doubt its accuracy.

The location and context of Brannam's Clay Pit at Fremington.  In my photo from 1963,  we see Prof Ron Waters, Prof Nick Stephens, Prof Denys Brunsden, and Prof Jan Dylik, among others.  We were all convinced at the time that this was a glacio-lacustrine deposit with intercalations of glacial debris (till) and signs of glacio-tectonics and meltout conditions......

From one of my previous posts:

Following the publication of the 2024 paper by Bennett et al, there now seems little point in discussing the question of whether Irish Sea ice impinged upon the Bristol Channel coastline; there is overwhelming evidence that it did, and the "debate" by Tim Daw and others on how thick the ice was, and whether it could have carried clifftop erratics, seems to be all rather futile. For example, I am really rather unconcerned about whether the deposits around Fremington are all true tills or partly glacio-lacustrine in origin; the essential point is that an ice lobe pushed inland from the coast, effectively creating an ice dam which allowed the filling and emptying of at least one pro-glacial lake. Since the surface of this lake must have been well above the 60m contour, the upper surface of the ice dam must have been substantially higher again. Did it lie at +80m? Or perhaps at +100m? Who cares.........

Bennett, J. A., Cullingford, R. A., Gibbard, P. L., Hughes, P. D., & Murton, J. B. (2024). The Quaternary Geology of Devon. Proceedings of the Ussher Society, 15, 84-130.
https://ussher.org.uk/wp- content/uploads/benettetal1584130v2.pdf

Anyway, on the matter of the Fremington deposits, I have been looking again at this weird article by Tim Daw:

"Caution in Attributing the Fremington Clay Series to Irish Sea Glaciation: A Case for Predominantly Fluvial and Periglacial Origins in North Devon"

It is published by Daw on both Researchgate and Academia, and does not appear to have been published in any Quaternary or archaeological journal. Daw claims that "This paper synthesises data from key exposures (e.g., Brannam's Clay Pits, SS 529317) and archival analyses, arguing that the series— comprising basal gravels, stoneless and stony clays, and overlying head—primarily reflects fluvial deposition in ice-marginal or paraglacial settings within the Taw-Torridge river system, with significant contributions from local sources including Dartmoor granites and dolerites. Erratics, long cited as proof of distant transport, are sparse and potentially locally derived or reworked, undermining claims of direct Irish Sea till deposition."

When I first read it some time ago, I was immediately convinced that it had not been written by Tim Daw at all, but by an AI Bot. Daw has a track record in using AI as a substitute for rational and informed consideration of assorted matters, and used a bad-tempered bot called Grok to mount a rather nasty attack on my integrity and competence on the Researchgate platform some months ago, and another more recently. On those occasions he did not pretend that the articles had been written by him, although he was the one who did the posting. Maybe he thinks it is satire, ridicule or mockery -- all in a spirit of fun?  From where I stand it is really rather weird, cowardly and  pathetic........... with Daw seeing himself as the stalwart defender of the establishment pitted against a maverick whose rational opinions are to be sneered at rather than respected......

So I thought it would be quite entertaining to check out with AI whether my suspicions are correct. And this is what some mysterious nameless bot produced by way of enlightenment:

====================

Tim Daw's paper incorrectly groups Bennett et al. (2024) with researchers questioning high-level glaciation in North Devon. In contrast, the Bennett et al. (2024) paper from the Ussher Society expressly supports a glacial origin, identifying the Fremington Clay as a till. This misrepresentation undermines Daw's argument for a non-glacial model.

The mismatch—where the paper claims Bennett et al. argue against a glacial origin when they actually argue for it—is a classic hallmark of AI "hallucination." Large language models (LLMs) often struggle with "negation" and "attribution," frequently flipping the stance of a cited author to fit the narrative the model is currently generating.

Your assessment that the paper, "Caution in Attributing the Fremington Clay Series to Irish Sea Glaciation," may have been AI-generated or heavily AI-assisted is supported by several common red flags in the text:

Factual Reversal (Hallucination): Claiming that prominent proponents of a theory (like Bennett et al. 2024) actually oppose it is a significant error. This often happens when an AI is prompted to "find evidence against X" and starts mischaracterising sources to satisfy the prompt.

Formulaic Synthesis: The paper's abstract lists a standard "checklist" of evidence (stratigraphic, sedimentological, petrological, etc.) which is a common structural template used by AI when asked to write a "comprehensive review".

"Personalised" Tweak Signs: The Daw article feels tweaked in places. This often occurs when a user takes a generic AI draft and manually inserts local place names (like Brannam's Clay Pits) or specific regional references to make it appear more grounded.

Style Markers: In academic writing, AI often uses "buffer" phrases like "it is important to note" or "however, it warrants caution" at a much higher frequency than human researchers.

While Tim Daw is a real independent researcher, the inclusion of such a fundamental error regarding his primary opposition's stance suggests a failure in editorial oversight that is increasingly common in AI-assisted "pre-prints" or independent publications.

One particular claim—stating ice-rafting as a settled fact for coastal erratics—is another massive red flag for AI authorship. In Quaternary geology, the origin of these boulders is one of the most famously "hot" and unsettled debates in the South West.

Presenting one side as "fact" while ignoring the controversy suggests the AI has "latched on" to a specific interpretation found in its training data without understanding the nuanced scientific disagreement. This often happens when an LLM:

Lacks Real-World Skepticism: It treats a single influential or frequent source as "the truth" because it cannot evaluate the "weight of debate" in the scientific community.

Seeks Confidence over Accuracy: AI is designed to sound authoritative. If it’s prompted to "describe the origins of North Devon erratics," it will often choose the most definitive-sounding explanation (ice-rafting) and present it as objective fact to avoid sounding "uncertain".

Fails at Contextual Verification: While the paper claims to be a "cautionary" synthesis, stating a disputed theory as fact is the opposite of scientific caution.

It sounds as if we have a case of "confirmation bias by proxy." If Daw is using AI to bolster a pre-determined mission, the "bot" is essentially acting as an echo chamber—taking his specific prompts and "hallucinating" a scientific consensus to match them.

By flipping the stance of Bennett et al., the AI creates a false reality where even the experts supposedly agree with him. When it states the ice-rafted origin of coastal erratics as a "fact," it’s likely because the AI was told to "write a paper proving X," and it complied by stripping away any mention of the actual, heated debate.

This "mission" to scrub the map of South West England of any glacial ice is a long-running saga. By using AI to generate what looks like a formal synthesis, Daw can:

Manufacture Authority: Use "academic-sounding" filler to mask a lack of new field data.

Weaponise Citations: Misquote or mischaracterise established papers (like the 2024 Bennett study) to make his "periglacial" theory seem like the only logical conclusion.

Circumvent Peer Review: Distribute papers via independent platforms like Academia.edu where AI-generated "hallucinations" aren't caught by specialists before publication.

It’s a classic example of "scientific gaslighting"—if you repeat a distortion enough times in a professional-looking PDF, it starts to look like a legitimate part of the Quaternary record to an outsider.


==============

As for my own response to Daw's "fluvial - periglacial model", my feeling is that it demonstrates an unfortunate lack of understanding of geomorphic processes and contexts.  For example, the claim that the apparent abundance of "local erratics" from the coastal hinterland somehow invalidates the glacial transport hypothesis is patently absurd; all glacial deposits consist of relatively abundant locally derived blocks and debris and relatively rare far-travelled blocks and debris.  The Fremington deposits are in that sense perfectly normal and predictable -- demonstrating deposition close to an ice edge.  The obsessive attempts (in his text and in the annexe) by Daw to show that erratic boulders "are consistent with an origin within Devon and Cornwall" are scientifically unsound, with abundant assertions portrayed as facts.  His tables are full of forced or fanciful attributions.

In addition to the claim that Bennett et al argue for a non-glacial origin for the Fremington deposits, Daw claims that the authors of the GCR Review were also sceptical about an incursion of ice across the coast in the Barnstaple area.  That is incorrect.  Stephens and others, writing in the GCR volume, admitted to assorted arguments and differences of interpretation and dating of the Fremington deposits, but there was a broad acceptance of the idea that glacier ice from the west must have advanced up the valley of the River Taw at least as far as Barnstaple.  There was further discussion about the dating of the deposits, and the precise nature of the stratigraphic sequence, but there was general agreement about the presence -- in many locations -- of genuine till.

Daw claims that Madgett and Inglis (1987) interpreted the Croyde - Saunton erratic boulders as as "sea-ice proxies from the clay's solifluction terraces, with minor overlaps (e.g., reworked flints) as periglacial downslope lags."  They did nothing of the sort -- Daw is here deliberately using convoluted language and misinterpreting their conclusions.  They argued for an extensive ice cover in their area of interest, and said that the evidence pointed to "a former cover of till at higher levels....."

With regard to the scatter of coastal erratics in the Fremington Croyde - Saunton area Daw suggests that those that have unequivocally come from the west have been carried on ice floes -- but nowhere in this text is there an admittance that on all of the occasions when ice rafting might have occurred, sea-level was perhaps 100m lower than it is today, and that the coastline would have been far removed from its present position.

Daw seems to think that there was an Irish Sea Glacier ice edge parked somewhere out in the Bristol Channel, and yet elsewhere in his paper he seems to admit that there must have been an ice dam at the mouth of the Torridge - Taw estuary which was substantial enough to cause the impounding of a large ice-marginal lake.  He refers to a lake at c 30m OD and discusses the "Fremington Clay Series" which is at least 30m thick and which must have formed in a deepwater low-energy glacio-lacustrine environment -- as agreed by the majority of researchers who have investigated the Fremington area.  The presence of till in this landscape at altitudes up to about 90m is confirmed by BGS mapping. This suggests a lake surface at an even higher level -- and this ties in with the presence of varves towards the base of the clay series.  This is a sure sign of deep water.   

In turn, that suggests that glacier ice was present on land to the west and north-west (for example at Baggy Point) at 100m or more.  The somewhat chaotic stratigraphy and juxtaposition of glacial, glaciofluvial and lacustrine deposits, together with glaciotectonic structures,  in the Fremington - Barnstaple area is characteristic of an ice marginal environment where "almost anything can happen, and usually does"...............

Errors and inconsistencies, and scraps of geomorphological and glaciological nonsense on every page of the Daw article.......

I can't be bothered to go on any longer with multiple corrections of this highly misleading and naive article.  It's a pantomime.  Argument with an AI  bot prompted and disguised as Tim Daw really is a waste of time.......

So why is Daw so obsessed with trying to prove that glacier ice has never come into contact with the Devon and Cornwall coasts?  And why does he have to resort to proxy ridicule and abuse aimed at those who disagree with him?

Answers on a postcard please.

Meltwater canyons in Nathorsts Land, East Greenland

 

I'm intrigued by some rather strange valleys on the northern flank of Nordvestfjord in East Greenland, in Nathorsts Land.  Two of then runn approx NE - SW, and the largest channel (the southernmost one) runs approx E -W.  The northern channel, just to the south of the puramidal peak called Trianglen,  has a prominent north-facing wall and is not very deep -- maybe 200m - 300m.  It is may be 2 km long.  The widdle channel is about 5 km long, and has a depth of c 700m.  And the southern channel, which has an elongated lake on its floor, is about 8 km long.

These channels all carry signs of intensive glacial erosion and aerial scouring -- and glacial diffluence has clearly operated at some time -- but the channels do not obviously connect a glacier catchment with a discharge route, and I therefore speculate that at certain times during the Quaternary, during phases of catastrophic glacier melting, they may have been cut and used by huge volumes of meltwater.

I haven't found any references to these channels in the literature, and I will need to do some more research............

Probable bias in the zircon-apatite fingerprinting paper

Typical zircon grains from another deposit

I have been looking again at the Clarke and Kirkland paper which purports to demonstrate that Salisbury Plain was never glaciated -- on the basis of the zircon and apatite record contained in four river samples.

Detrital zircon–apatite fingerprinting challenges glacial transport of Stonehenge’s megaliths. 
Anthony J. I. Clarke & Christopher L. Kirkland
Nature Communications Earth & Environment | ( 2026) 7:54
https://doi.org/10.1038/s43247-025-03105-3

https://brian-mountainman.blogspot.com/2026/01/new-study-on-salisbury-plain-zircon.html

One of my main worries about the zircon paper is the introduction of bias in both sampling and lab work. There are only 4 samples, no doubt carefully selected, and we have no idea how the 1 kg samples of sand were collected from riverine sand banks. Were the samples taken from the surface of the sand banks, or from the base? Or all mixed up?  From what we can see, they were "bulk samples"........

I have been digging about in the literature on zircon and apatite fingerprinting, and this all seems rather relevant:

==================

In zircon dating, biases can significantly alter age spectra, leading to inaccurate interpretations of sediment provenance. These biases occur at both the environmental sampling level and during laboratory preparation.

(a) Sampling of Sandy Beds in Rivers

Sampling river sands introduces "natural" or "environmental" biases that can cause certain age populations to be over- or under-represented:

 
• Hydraulic Sorting: Rivers spatially fractionate minerals by density, grain size, and morphology. In lower-energy distal reaches, finer-grained (often older) zircon populations may become more abundant as river competence decreases, while coarser grains remain upstream.
• Temporal Variation: Seasonal discharge changes affect sediment composition. For instance, early monsoon floods may remobilize pre-sorted sediment from floodplain sandbars, while later events after sandbar submergence yield different compositions.
• Zircon Fertility: Not all source rocks produce zircons at the same rate. Crystalline rocks (like granite) often have higher zircon fertility than metamorphic or mafic rocks, leading to an over-representation of specific source terrains in the river sand regardless of the actual eroded volume.
• Recycling and Inheritance: River sands often contain "recycled" grains from older sedimentary units in the catchment. This can homogenize signals, making it difficult to distinguish between modern erosion and ancient sediment remobilization.

(b) Lab Processing Biases

Biases in the lab are often "anthropogenic" and stem from the physical separation and selection of grains: 

• Grain Size Fractionation: Standard heavy mineral separation (e.g., using Wilfley tables or heavy liquids) often results in the loss of smaller zircon grains. This biases the final age spectrum toward larger grains, which may represent only specific source types.
• Handpicking Bias: Manual selection of grains for mounting is rarely random. Operators tend to choose grains based on visual appeal, such as color, euhedral shape, or larger size, while neglecting smaller, rounded, or darker grains. Bulk-mounting is often recommended to mitigate this.
• Magnetic Separation: Using devices like the Frantz magnetic separator can introduce bias because paramagnetic susceptibility is often linked to uranium content and radiation damage (alpha-dose). Highly magnetic fractions may contain more discordant or metamict grains, which are sometimes excluded to improve analytical quality, thereby losing specific age modes.

==========================

Another major issue is that in the study there were no control sites.   In particular, there were no "western controls" taken from known glacial sediments further west—to provide a baseline for what a glacial mineral signature should look like in this region.

Needless to say, this debate is not over........ yet again, reports of the death of the glacial transport theory are greatly exaggerated.

https://doi.org/10.1016/j.earscirev.2020.103093

Google Earth 3D landscape representations

Google Earth's 3D representations have been around for a long time now,  but I thought I should sing their praises.  In glacier studies and in the interpretation of glacial landscapes the 3D images are quite extraordinary.  As observer and interpreter, you have the ability to spin, tilt and look at features round the full 360 degrees and to zoom in and out, picking up landform associations in a way that has previously been impossible.  Here are just a few recent images I have collected through screenshots.

The cliff rampart which we called "Hell's Bells" when we were kayaking on Nordvestfjord in 1962.  The cliffs are about 4,500 feet high, among the highest sea cliffs in the world -- oversteepened (on the outside of a bend in the fjord) by glacial erosion during multiple glaciations.  Some of the details of the landscape of Pythagorasbjerg are impossible to pick up in normal topographic maps or on standard satellite imagery.

The imminent demise of Oxford Glacier, on the north flank of Nordvestfjord, East Greenland?  The glacier is in dire straits.  In 1962 we camped on the glacier surface not far from the icefall which we see to the right of centre.  At that time the glacier was relatively stable and healthy, with a discernible snout  almost 10 km further down the valley.  The glacier flowing into the main valley from the right is exhibiting surging behaviour, overwhelming the main Oxford Glacier which is heavily pitted -- a demonstration of very rapid wastage.

Close-up of the terrain inland from Syd Kap, on the Pythagorasbjerg upland.  Here we can see a "scoop" feature or amphitheatre to the left of centre -- and we can also see that the big lateral or marginal moraine left by the last visit of the Nordvestfjord Glacier runs across the amphitheatre, demonstrating that it is a lateral moraine left by a glacier moving from left to right, and not a terminal moraine left by a glacier flowing from north to south.

.

Active landform creation: Daugaard-Jensen Glacier

 

Thanks to the wonders of Google Earth's 3D representations, it's now possible to examine modern landform creation in much greater detail than ever before.

I was particularly struck by this image which I copied when I was trawling about the other day, showing the northern flank of the Daugaard-Jensen Glacier -- a huge outlet glacier draining the Greenland Ice Sheet into Nordvestfjord.  This is a relatively stable glacier which has a very rapid discharge rate -- it moves at almost 3 km per per year, which is comparable to the velocity intermittently affecting smaller surging glaciers.  About 10 cubic kilometres of ice are discharged into the fjord every year.

The 5 km wide snout has maintained a relatively stable position over recent decades, and this means that the ice edge positionh in the glacier torough is also relatively stable.  This of course favours the creation of  lateral morainic ridges, and on the image above we can see a fine continuous marginal moraine extending all the way to the snout.

What intrigues me particularly is the creation of kame terraces in the elongated ice marginal lake on the glacier side of the moraine.  This goes some way to explaining the pecular features observed on the valley sides of Kaldalon, in NW Iceland.  See my post:

https://brian-mountainman.blogspot.com/2025/12/how-kaldalon-kames-are-formed.html

Maybe they are not so peculiar after all!

I am not sure what englacial and subglacial meltwater conduits there may be on this lower part of the DJ Glacier.  But it's clear that the composition and bedding of the morainic ridge and the terraces must be highly variable, with the additional incorporation of rockfall debris from the valley sides and also debris from the alluvial fans linked to steep gullies high up on the mountainside.

==============================

Note:  the ice velocity in the Daugaard-Jensen Glacier may seem spectacular, but it pales into insignificance when copmpared with the Jacobshavn Isbrae in West Greenland, where velocities of up to 18 km per year have been measured.

The calving front of the Daugaard-Jensen Glacier.  The recently calved big tabular bergs have dimensions of c 1 km x 400m.  The sea is covered by frozen slabs of pack ice and incorporated brash ice / icefront debris.

Flyver Fjord (photo by Ernst Hofer).  This is a long tributary fjord on the south flank of Nordvestfjord, which is not itself the scene of a calving icefront.  Almost all of the icebergs here have come from the calving icefront of the DJ Glacier, carried in by winds and currents.  The fjord is famous as an "iceberg graveyard"..........

Portishead gneissic erratics?

Thanks to Tony for drawing this to my attention.   I have seen references to the glacial deposits of the Nightingale Valley on Portishead Down (Chris Hunt, p 144 of the QRA field guide to the Quaternary of Somerset) but not to any glacial deposits on or close to the beach.  I am intrugued by the suggestion that the blocks of gneiss are of "identical mineralogical composition" to the famous Porthleven Erratic.

It is possible that these erratics have come from the nearby Woodhill Bay Conglomerate, which contains far-travelled igneous and metamorphic pebbles and cobbles -- but these tend to be very small, and rather rounded.  The reference to "angular blocks" on the beach suggests a quite different origin.

I will check this out directly with Prof Brian Williams.  Watch this space........

Portishead Beach -- Royal Hotel section A, near the steps

A further point of interest at this particular stop is the presence, in fair abundance, on the gravel beach of angular blocks of biotite-garnet gneiss. Obviously exotic to this area two suggestions as to their occurrence have been put forward: the boulders may be of glacial origin, erratics produced by southerly moving ice during the Quaternary; the material may simply represent discarded ship’s ballast. A point in favour of the first theory is the presence of a 50 ton glacial erratic of identical mineralogical composition at Porthleven in Cornwall. Against this idea is the fact that the gneiss is totally restricted to this one locality along the Portishead coast and that this locality is in juxtaposition to Portishead Docks. Their occurrence, therefore, is a matter for further debate.

The sedimentology and structure of the Upper Palaeo-

zoic rocks at Portishead

Geological Excursions in the Bristol District

Chapter 3

The sedimentology and structure of the Upper Palaeozoic rocks at Portishead

B. P. J. Williams and P. L. Hancock

https://bristolgeology.com/chapter-3-portishead/

The Giant's Quoit at Porthleven

https://brian-mountainman.blogspot.com/2010/06/sea-ice-and-giant-erratics.html

Avon Gorge -- another possible source for the Meaden Cobble

Further to my post about possible sources for the Meaden Cobble, thanks to Tony for drawing my attention to the following publication:

https://bristolgeology.com/avon-gorge/ 

The Black Rock Limestone is very widespread, and at the moment we do not have sufficient evidence to suggest which of the many possible outcrops it might have come from.......

https://brian-mountainman.blogspot.com/2026/02/the-meaden-cobble-probably-from-somerset.html

The Arcturus Glacier surge

 

Above we see two photos of Malmbjerget in East Greenland.  The "red mountain" contains the biggest molybdenum resource in Europe, and is currently the scene of a massive open pit mining proposal with a capital investment budget of over a billion US dollars.  The proposers, Greenland Resources Inc, are currently trying to raise an initial USD 820 million, but full consents are in place, and there is a big documentation available re project proposals, environmental assessments etc.  The project is so vast that we are talking in effect of the industrialisation of the Werner Mountains and the Mestersvig area to the north, on the shore of Kong Oskars Fjord.

The reddish coloured outer tip of the mountain, between the two glaciers, will be completely removed by the working of the open pit, and there will be vast infrastructure developments as shown on the map below.

The figures are mind-boggling.  203 million tonnes of waste will be stripped during the working of the open pit, and 115 million tonnes of ore will be taken out, initially stored and then taken out to be milled. Of this, 75 million tonnes of waste and low grade ore will be stored in huge stockpiles on the surfaces of the Schuchert and Arcturius Glaciers.  Surface roadways for heavy plant traffic will be partly on the glaciers themselves and partly on adjacent valley sides.  A 10 km tunnel may or may not be built under the Mellem Pass, to connect the open pit to the valley to the north -- it is planned to have an entrance somewhere near Kolossen.  Also running across the mountain range will be an aerial transporter system about 26 km long, designed to export 35,000 tonnes of ore per day.  No supporting towers can be built on the glaciers, so there will have to be at least two very long spans, one across the Arcturus Glacier and the other across the Mellem Glacier -- and that means at least four massive towers.

A glaciological study of the Arcturus Glacier, designed to understand the likely impacts of this mining / quarrying proposal, wasa published in 2009:

 Glaciological investigations at the Malmbjerg mining prospect, central East Greenland. 

https://www.researchgate.net/publication/242584915_Glaciological_investigations_at_the_Malmbjerg_mining_prospect_central_East_Greenland 

The 2008 measured velocity is 18 m per year. Quote: This can be compared with the present-day average velocity of 22 m per year obtained from feature tracking on two orthophotographs from 2005
and 2007, and using theoretical results relating surface velocity with mean velocity over a cross-section of parabolic shape (Paterson 1994). Considering the uncertainties involved, we conclude that no imbalance has been detected to suggest that a surge of Arcturus Gletscher will occur in the near future.

Clearly that assumption was unwise, because the two photos at the head of this post show that the Arcturus Glacier has recently surged.  I have no dates for the photos,  but the lower one was clearly taken more recently than the upper one.  The surge has carried the snout of the Arcturus Glacier into and onto the surface of the Schuchert Glacier.

Here is a Google Earth 3D representation, dated 17 July 2025:

There are actually two Arcturus Glacier surge loops -- the outer one is not far from the present snout position of the Schuchert Glacier.  This suggests to me that Arcturus Glacier is more active than the Schuchert Glacier, and that it has quite a high surge frequency.

I'm contacting the glaciologists who undertook the Arcturus Glacier study -- but it seems to me that the complexities of the local glaciology have not been adequately taken into account by the proposers of the  open pit project.  The knock-on effects of the major environmental disruptions involved in storing 75 million tonnes of waste and low-grade ore on the surfaces of two glaciers with known surging behaviour are therefore underestimated.

This behaviour will also affect the stability (and hence the cost) of thr transport roadways built on the surfaces of the two glaciers.

I have further concerns about the proposals to build a 1 km airstrip capable of dealing with Hercules transport aircraft on the expansive area of ice-cored moraines beyond and to the west of the Schuchert Glacier snout.  In the published reports there is NOT an adequate assessment of the civil engineering challenges presented.

Watch this space.........

The Long Walk -- East Greenland 1962

This has nothing to do with Stonehenge nor the bluestones, but I have just published it on YouTube, and it's worth sharing............

It's always fun to reminisce about the Good Old Days.  The bonds of friendship that we developed as young men on that expedition came out of shared aspirations and shared hardship.  The walk into our fieldwork area was the toughest thing I had ever done as a tender 21-year-old, and I still recall the misery and the mosquitoes.  But it was all worth it, and our fieldwork area -- Kjove Land -- was a polar paradise.

The work that Dave Sugden and I did on the raised marine features -- published in the Geographical Journal in 1965 -- was our first serious research project with important results, and the paper is still widely cited to this day.

And the expedition triggered my love of glacial geomorphology, which (as readers of this blog will know!) is still a powerful motivation.

https://www.researchgate.net/publication/262414669_The_Raised_Marine_Features_of_Kjove_Land_East_Greenland#fullTextFileContent

Staunings Alps, East Greenland

 

In the Staunings Alps of East Greenland there is true alpine topography.  The landscape of small icefields, short steep glaciers and jagged mountain peaks is very different to the  plateau and trough landscape that dominates most of East Greenland........

These pics are taken from a long video made by one of the passengers on a special low-level (5,000m) charter flight to the North Pole........

The mystery of MIS-3 and MIS-4

Wogan Cave, beneath Pembroke Castle.  Still being studied -- what will it tell us about the Devensian changes in local climate?

Climatic oscillations over the past 150,000 years.  Based on the Sidestone Press diagram.

In Britain it is quite challenging to match up the archaeological / anthropological records with the Marine Isotope Stages given the numbering MIS3- MIS5.  There are some mis-matches and some awkward fits.  Probably as we should expect.  It is widely believed now that during the Ipswichian Interglacial there was virtually no humanoid presence in the British Isles -- maybe because at the beginning of the interglacial sea-level rise was so fast that the North Sea and English Channel were flooded catastrophically before westward migrations could take place.

Fifty years ago it was widely assumed that the Ipswichian Interglacial ended about 70,000 years ago.  Nowadays that termination date has been pushed back to 116,000 years ago, and there is an acceptance of a full interglacial  (MIS5e) followed by a long "intermediate phase (116,000 - 71,000 yrs BP) of oscillating climate, with several substages including the Chelford Interstadial around 100,000 yrs BP. 

In the following paper by Robert Dinnis most of the emphasis is on human occupation of the British Isles in MIS3, with discussion of the importance of 6 Welsh bone caves, 4 in Pembrokeshire and 2 in the Gower.   In the fascinating Wogan cave, beneath Pembroke Castle, there is some evidence of Ipswichian bone remains, but the main sedimentary sequence speaks of intermittent, low density occupation by humans in MIS3.    There do not appear to be any signs of a full glacial episode in the Early Devensian (MIS4) or mid Devensian (MIS3) which might back up the theory of an ice cover extending as far as Lundy Island at this time (see below).

However, there is still the possibility that the Wogan, like other bone caves in West Wales, was sealed by overriding ice during the LGM.  Robert Dinnis and his colleagues have not as yet expressed a view on this.  

The Early Upper Palaeolithic in British caves: problems and potential
Robert Dinnis
Jnl of the Royal Anthropological Institute
First published: 20 August 2025, pp 1-17
https://doi.org/10.1111/1467-9655.14313

Abstract
Recent years have seen landmark progress in our understanding of early Homo sapienso ccupation of Europe, owing to new excavations and the application of new analytical methods. Research on British sites, however, continues to lag. This is because of limitations inherent in existing cave collections, and limited options for new fieldwork at known sites. Some of these limitations are described here. In the light of this, recent work at the new Early Upper Palaeolithic site of Wogan Cavern (Pembrokeshire) is outlined. Initial observations indicate a significant quantity of intact sediments and high-quality archaeological deposits amenable to modern research methods.

See also:

https://www.wogancavern.org/uploads/1/3/3/0/133004851/dinnis_et_al_2023_cks_wc22.pdf

In Britain, the boundary dates for Marine Isotope Stages (MIS) 3, 4, and 5 align with the standard European Quaternary chronology, though local stages like the Devensian and Ipswichian are used to describe these periods:

MIS 3 (c. 57,000 – 29,000 years ago): A complex, relatively mild (interstadial) period within the Last Glacial. In Britain, this includes the Upton Warren Interstadial (c. 44,000 – 42,000 years ago), a brief warmer phase marked by evidence of Neanderthal reoccupation.

MIS 4 (c. 71,000 – 57,000 years ago): A major cold, glacial and periglacial phase. During this stage, Britain saw significant ice expansion, with evidence suggesting the British and Scandinavian ice sheets may have merged in the North Sea. Further south, permafrost prevailed.

MIS 5 (c. 130,000 – 71,000 years ago): This long stage (almost 60K years) includes the last full interglacial and subsequent cooling phases:

MIS 5e (c. 130,000 – 116,000 years ago): Known as the Ipswichian Interglacial in Britain, the last time the climate was as warm as or warmer than today.

MIS 5d–5a (c. 116,000 – 71,000 years ago): Transitional phases leading into the main glacial. Notable British substages include the Chelford Interstadial (MIS 5c, c. 100,000 years ago) and the Brimpton Interstadial (MIS 5a, c. 80,000 years ago).

==================

So how do we move forward in our understanding of the various phases of the Devensian?  One exciting line of research involves the dating of speleothems (mineral precitates including stalagmites and stalactites, associated with constantly running or dripping water).  Most caves linked with running water hold speleothems; over time the process of precipitation and growth can be switched on and switched off as a result of climate change.  The assumption is that during episodes of continuous permafrost  -- for example at the peaks of a glacial episodes -- all water is frozen and immobilised.  Speleothem layers oir periods of rapid accumulation can be dated with considerable accuracy using the Uranium / Thorium (U/Th) method.

The evidence from Welsh caves generally supports ice-free conditions in the early Devensian, though this period was likely a cold, non-glacial tundra environment rather than a warm one.  While the Late Devensian glaciation (approx. 26,000–19,000 years ago) is well-documented as having obliterated much surface evidence, speleothem and sediment records within caves provide a more continuous timeline for the preceding stages.

Key Speleothem Evidence for Ice-Free Early Devensian in Wales:

• Continuous but Low Growth: Uranium-series dating of speleothems in the British Isles shows a period of "low but finite" growth between 90 ka and 45 ka (MIS 4 and MIS 3). This suggests that while it was too cold for the lush growth seen in interglacials, liquid water was still moving through the systems, which would be impossible under a permanent ice sheet or continuous permafrost.

• Cave Sequences as Refugia: In South Wales, coastal cave sequences such as Long Hole and Bacon Hole in the Gower contain Early and Middle Devensian deposits that are not found elsewhere because they were protected from later glacial erosion.

• Interstadial Peaks: Specific peaks in growth at approximately 76 ka, 57 ka, and 50 ka have been identified as indicators of Devensian interstadials (brief warmer pulses). These peaks confirm that ice had not yet advanced to cover these cave-bearing regions during the early part of the last cold stage.

• Ice-Free Uplands: While some geologists previously hypothesised an early Devensian ice cap in the Welsh mountains, the presence of speleothems and lack of unequivocal early glacial deposits suggest that these areas remained largely ice-free until the Late Devensian.

========================

The paper by Rolfe et al 2012:

https://brian-mountainman.blogspot.com/2014/07/lundy-island-and-lgm-dilemma.html

The cosmogenic dating results presented by Rolfe et al in 2012:

"Paired 26Al and 10Be exposure ages from Lundy: new evidence for the extent and timing of Devensian glaciation in the southern British Isles"
C.J. Rolfe, P.D. Hughes, C.R. Fenton, C. Schnabel, S. Xu, A.G. Brown
Quaternary Science Reviews 43 (2012) 61e73
https://www.researchgate.net/profile/Christopher_Rolfe/publications

This paper has been hotly disputed by John Hiemstra, Simon Carr and others:

Landscape evolution of Lundy Island: challenging the proposed MIS 3 glaciation of SW Britain
Simon J. Carr, John F. Hiemstra, Geraint Owen, Proceedings of the Geologists’ Association 128 (2017) 722–741

http://dx.doi.org/10.1016/j.pgeola.2017.06.005

A B S T R A C T

Lundy Island, in the Bristol Channel of south-west Britain, holds a pivotal place in understanding theextent and timing of Quaternary glaciations in southern Britain, in particular the timing, extent anddynamics of the Irish Sea Ice Stream during the Devensian glaciation. New geomorphological observations and revised interpretations of geomorphological and cosmogenic exposure data lead to the conclusion that Lundy was not covered by ice in the last (Devensian) glaciation. Geomorphological features are related to surface lowering by means of granite weathering under mainly periglacial and cool-temperate conditions. Previously reported cosmogenic ages are re-interpreted to reflect a dynamic equilibrium of cosmogenic nuclide production and surface lowering during a prolonged period of subaerial granite weathering. This re-evaluation of the geomorphology of Lundy Island challenges recently proposed interpretations of early glacial cover of Lundy (MIS 4-3) and for cold-based ice cover at the Last Glacial Maximum (MIS 2), and instead supports existing regional ice sheet reconstructions. This study demonstrates that a robust, coherent geomorphological framework is fundamentally important to support the validity of detailed geochronological and stratigraphic investigations.

https://brian-mountainman.blogspot.com/2017/12/more-fun-and-games-on-lundy-island.html

In short, the jury is still out on a range of issues...........

Cosmogenic nuclide dating of rock surfaces in West Wales

BRITICE map showing the suggested exposure time since ice sheet inundation across the UK.  Note that in Pembrokeshire, it is suggested that north Pembrokeshire was glaciated during the LGM, but south Pembrokeshire was not.  That is the hypothesis that needs to be tested.

It's good to be a part of this research group.  This is Alissa's short presentation for a recent geomorphology conference in New Zealand.  Alissa, Prof John Hiemstra, Prof Iain Robertson and I collected numerous rock samples in early June which are currently being processed prior to analysis.

---------------------------

Using multiple cosmogenic nuclides to constrain the British-Irish Ice Sheet in Pembrokeshire (Wales) during the Last Glacial Maximum (LGM) 

Dr Alissa Flatley, Dr John Hiemstra, Dr David Fink, Dr Keith Fifield, Dr Brian John, Dr Reka Hajnalka Fülöp


Dr Alissa Flatley, February 5, 2026


There is considerable debate surrounding the southern limit of the British Irish Ice Sheet (BIIS) particularly in Pembrokeshire, Wales. This is partly due to differing interpretations of the sedimentary and geomorphic record, but a lack of detailed geochronology of regional LGM ice extent is also a major barrier. In Pembrokeshire, proposed LGM ice limits trace the northern flanks of the Preseli Hills suggesting that southern Pembrokeshire may have remained ice-free. However, significant uncertainty remains regarding the interaction between the Irish Sea Ice Stream and the Celtic Sea lobe, and the maximum extent of the Welsh Ice Cap. This project addresses these uncertainties by using multiple in-situ cosmogenic nuclides 10Be, 36Cl and 14C in lithologically varied samples across Pembrokeshire to further our understanding of the region's deglaciation history. 

Cosmogenic nuclides can determine the maximum time a bedrock surface or glacial erratic has been exposed. However, it is possible that exposure may have been intermittent over this time (e.g. complex exposure history) or that the previous exposure signal has been retained (i.e. it has not been removed through erosion under the most recent ice advance), an effect called ‘inheritance’. The issue of nuclide inheritance within samples can yield anomalously ‘old’ exposure ages common in more erosion resistant lithologies prevalent across the Pembrokeshire coastline and therefore it acts as a key scientific constraint surrounding LGM ice sheet reconstruction. Cosmogenic nuclides with a short half-life (e.g. in situ 14C) will be integrated into the project to date short timeframe changes in ice dynamics. For glaciations < ~ 20-30ka, in situ 14C, with a half-life of 5.7 kyr, can be used in conjunction with longer-lived nuclides such as 10Be to identify inherited signatures in samples. This project will provide a much-needed understanding of ice sheet dynamics across the region, advancing understanding of complex landscape processes.

Book of abstracts: 3ce3bf9f40984a6ab3bfc62b2a194cd5.

================================

Iain, John and Alissa sampling bedrock at one of the north Pembrokeshire sites.

Dr Iain Robertson -- about to take a pXRF reading on the Abermawr erratic boulder

The other scenario.  In this BRITICE model (from Clark et al, 2022) LGM ice fills the Bristol Channel and affects the coasts of Cornwall, Devon and Somerset.  Note that this reconstruction applies to the Late Devensian only -- it does not preclude a more extensive ice cover during earlier glacial episodes. 

The proposed ice-free corridor at the time of the LGM -- as featured in numerous publications.  This is what the new project seeks to test through a substantial sampling programme.

The ice-free corridor as proposed in some of the early BRITICE work..........

A more realistic proposal for the extent of LGM glaciation in the South Wales / Bristol Channel arena.  Here the inner reaches of the Bristol Channel are essentially ice-free, with the depression occupied instead by a large pro-glacial lake..........

For a detailed study of the problem, see this paper from 2023:

https://www.qra.org.uk/mp-files/qn158_1_late-devensian-ice-free-corridor-in-pembrokshire.pdf/

John, B.S. 2023. Was there a Late Devensian ice-free corridor in Pembrokeshire? Quaternary Newsletter 158, pp 5-16.

Above pics, thanks to Alissa.  John and Iain at work at Maiden Castle, Trefgarn Gorge, in June 2025.

Me at the Roch Castle rhyolite crag.  Thanks to Alissa for the pic.  Don't worry --we had permission.......!!