The Geology of Omaha Beach

October 16, 2011 11:00 AM

D-Day's Legacy: Remnants of invasion linger in beach sands - an analysis of the debris left in the sands at Omaha Beach from D-Day.

Geologists were active in preparing for the invasion as well.

Although there were geological maps these didn't give enough fine detail and even after careful planning things had to be changed only a month before D-Day because a storm shifted the surface layers. My dad was flown over the beaches at great risk to try and make out the nature of the ground and take photos but this didn't show enough detail and commandos had to make forays on to the beaches to get samples.

An archive of geologically related D-Day material is on display at the University of Birmingham’s Lapworth Museum with a particular emphasis on the work of Prof Fred Shotton.

posted by thatwhichfalls (28 comments total)

I'm sure glad the didn't use land mines back then
posted by Renoroc at 11:04 AM on October 16, 2011

I'm sure glad the[y] didn't use land mines back then

What? Of course they did. Vicious ones, in fact.
posted by mojohand at 11:11 AM on October 16, 2011 [3 favorites]

I'm sure glad the didn't use land mines back then

Oh, they did. The French authorities had German PoWs clear the minefields after the war...
posted by Skeptic at 11:15 AM on October 16, 2011 [2 favorites]

Anthony Beevor's book on D-Day is worth reading. It was an incredibly brutal campaign that matched the Eastern Front in terms of relative numbers of casualties.
posted by KokuRyu at 11:19 AM on October 16, 2011

Last time I was in Normandy, I went to the American Cemetery and then walked down the path to the beach. It was pretty foggy, but there were plenty of sunbathers. I waded a bit in the water-the entire time thinking, "dude, I'm wading in bloody omaha". Which is weird. But, also, kind of totally wonderful. There's those bunkers and memorials and....the beach...with normal people doing normal things (there's cows too, up above). Which, despite the dissonance, is what peace is supposed to look like.
posted by atomicstone at 11:24 AM on October 16, 2011 [12 favorites]

The link in the OP is down for me. Anyone else?
posted by codacorolla at 11:25 AM on October 16, 2011 [1 favorite]

Yeah same here.
posted by EndsOfInvention at 11:27 AM on October 16, 2011

It loaded for me, but it tok some seconds.
posted by mosk at 11:35 AM on October 16, 2011

Proof that the Earth, once it's rid of us, will eventually recover.
posted by tommasz at 11:36 AM on October 16, 2011

Errr... "...took me some seconds."
posted by mosk at 11:39 AM on October 16, 2011

Renoroc: just a quick side note to mention that versions of landmines go back to something like 1400 in China, and around 1570 or thereabouts in Europe. (And I personally own a small chunk of one from WWI.)
posted by easily confused at 11:48 AM on October 16, 2011 [1 favorite]

I sit corrected. thanks!
posted by Renoroc at 12:56 PM on October 16, 2011

Couldn't get the main link to work either, but was reminded how great the People's War site is. Reading that link, it answered my first thought about sending commandos for soil samples - they did also send them to beaches they weren't planning to land at to avoid tipping off the German defenders.
posted by Abiezer at 1:37 PM on October 16, 2011

There are still rather vast stretches of desert in North Africa near El Alamein that are quite dangerous due to the vast number of mines under the sand. Rommel's Panzer Army Africa laid about half a million mines around there and they're still being found.

Great links. Thanks for posting.
posted by dazed_one at 1:48 PM on October 16, 2011

I am not a war strategist or anything like that but I have always had this idea for clearing mine fields and now you can tell me why it would never work:

Ahem. Carpet bomb them with ice broken into blocks.
The ice sets off the mines, which explode and then melts.

Yes? No? Too dumb?
posted by Senor Cardgage at 2:52 PM on October 16, 2011 [3 favorites]

Why ice? Who cares if it melts or not? You may as well use rocks. Either way, just dropping stuff is unlikely to reliably set off the mines unless you land directly on top of them. Conventional bombs probably work better as the shockwave will set off nearby mines if you don't get a direct hit. In reality, they ended up using mine-clearing tanks with flails on the front (among other devices). Also - from Wikipedia:
In addition, there were modified landing-craft: eight "Landing Craft Gun", each with two 4.7-inch guns; four "Landing Craft Support" with automatic cannon; eight Landing Craft Tank (Rocket), each with a single salvo of 1,100 5-inch rockets; eight Landing Craft Assault (Hedgerow), each with twenty-four bombs intended to detonate beach mines prematurely.
posted by EndsOfInvention at 3:03 PM on October 16, 2011

Senor Cardgage: They do use, for example, fuel-air explosives to clear minefields based on basically that principle. Problem is, there are many kinds of mines with many kinds of triggers, partly in order to make minefields harder to clear (and also to try to distinguish what to blow up or not blow up: people, vehicles, animals, etc).
posted by hattifattener at 5:41 PM on October 16, 2011

Ahhhhh. Thats the stuff. Thanks for sating my curiosity, can always rely on the hive :)
posted by Senor Cardgage at 6:13 PM on October 16, 2011

Google cache of the article. The server cannot handle our massive invasion.

I got to morbidly wondering what it would be like to wander around the beaches of Normandy with a metal detector. As always, Youtube delivers (warning: boring).
posted by qxntpqbbbqxl at 6:40 PM on October 16, 2011 [1 favorite]

Thanks for the link qxnt.......
posted by mearls at 7:27 PM on October 16, 2011

4% shrapnel is far more than I would have thought. Interesting.
posted by jimmythefish at 8:56 PM on October 16, 2011

The U.S. and British Royal Navies provided sea transport

Bets kept secret - the US Royal navy?
posted by mattoxic at 5:07 AM on October 17, 2011 [2 favorites]

Best
posted by mattoxic at 5:07 AM on October 17, 2011

Senor Cardage, it's a nice idea but it likely wouldn't work for a number of reasons.

Firstly, there's a sense in which removing some of the mines in any given field or set of fields is pointless. If some remain, the ground in which they lie remains too dangerous for many uses. So (without this being an absolute truth) you have to try and get em all out.

Second, you're going to have a hard time getting enough ice in the air to detonate all mines in an area which has undergone indiscriminate or area-denial mine laying, such as that in Afghanistan during the Soviet War or Cambodia during the post 1975 conflicts. Although mine removal proceeds, and many mines do become ineffective over time, there were huge areas of both countries that had mines laid at densities > 1 per square meter. Multiple campaigns of seeding the same areas of ground by multiple armies. There's never going to be enough planes or ice to deal with some of those fields.

Third, in situations where anti personnel mines were laid in a more targeted fashion to deny access to smaller areas of ground, to concentrate enemy approach routes, to target particular forces or individuals and so on, they're often not laid in nice flat open fields. In Afghanistan they were often laid in the same places that IEDs are now laid - road culverts, in walls, behind rocks that provide cover on the approach to a fortifications or ridgelines, etc. In Cambodia, popular targets were road culverts, rice paddy dykes, thickets of rattan or bamboo, the banks of rivers near bridges - again, areas that might provide cover. The key thing about this sort of mining is that you can't necessarily hit it from above. Not even with a metal detector or hand probe. So ice coming down from above, say on top of a stone wall or crashing into a 50 year old rattan grove, may not have any impact at all.

Fourth, like the grains of shrapnel and glass found on Omaha in the linked article, mines migrate. This is more the case in areas with annual heavy rainfall (Cambodia, Mozambique, Zambezi Valley in Zim.) than it is in places without (Afghanistan, the Western Deserts), but the simple answer to why they do it is that soil and the objects in it are dynamic. Layers of soil move, the mines float or sink (or head sideways), the roots of vegetation push things around, etc. The key problems for aerial demining here would be mines that have sunk too deep to be detonated by your ice but aren't too deep that a plow won't hit em, or ones that sink the season before you drop your ice, then rise the season after. You may well even get some that float because a whole lot of ice has just melted above them.

Fifth. As hattifattener has said, technical shit. Even the Khmer Rouge mine factory in Pailin in the late nineties was capable of producing a mine that required the weight of a human to detonate. Goat wouldn't do it, buffalo wouldn't do it. And those guys were basically pumping out cat food tins with a pressure trigger and a tilt switch. But during the years in which they laid mines, they didn't just lay one type. They laid dozens of types (to be polite) "based on" models from at least a dozen countries. Same deal in Afghanistan. So even if you got your blocks of ice exactly the right size, and your plane flying at exactly the right height and speed so that your falling ice simulated the weight of a human foot step, in many places it's not going to work on all types of mines laid.

Sixth. Lot of places, no-one remaining in the mined region knows where they are. At the end of the Rhodesian civil war, the guys who laid the mines mostly left the country and headed south (then the bush grew back and there was nothing to do but fence off very large areas of land). The Soviets weren't all that keen to help any of the Afghan regimes that followed them with demining, and their mine laying was so indiscriminate (some of it was aerial) that they probably couldn't have anyway. In Cambodia, there was a somewhat famous instance where a mountain (Bokor) was cleared with the assistance of the guys who laid the mines. But they were anti-tank mines, they were limited in number, a map had been made because they were unusually valuable, and the story goes that they know they missed one. But in general a lot of the mapping of fields in Cambodia was done via collating casualty reports - by the late nineties that was via the Cambodia Mine Incident Database. Groundbreaking project, but a horrific idea. We find the mines by collating all data about people setting them off..

To get to the point on this one - where do you drop your ice? In many heavily mined countries, you just don't know.

To extend things just a little on that last point, when you have a situation like that currently taking place in Southern Sudan, where the Bentiu - Tharjath airstrip road has been repeatedly cleared, and repeatedly remined, by people who then get killed, driven off or flee the country as refugees, your knowledge of where the mines are is reduced to less than zero. At that point you're stuck waiting the conflict out, then using men with probes. Same as always.

Anyway, I'm exceeding my knowledge in some ways here, so I'll stop. I think your idea is a wonderful one, but it's impractical.
posted by Ahab at 7:15 AM on October 17, 2011 [7 favorites]

Beevor's book is very good but the audiobook is very hard to listen to, thanks to the British voice talent who tries to do accents. Terrible, terrible accents.

Also, isn't this what goats -- cheap, self-replacing, and manure-producing -- are for?
posted by wenestvedt at 7:28 AM on October 17, 2011

Very interesting, semi-related story about tidal predictions and how important these predictions were to the success of the landings.
posted by dseaton at 8:29 AM on October 17, 2011

In this age of specialization, there is a dedicated journal to mines, with an interesting article on unexploded ordnance WWI and WWII.
posted by IndigoJones at 10:40 AM on October 17, 2011

dseaton, the article about tide prediction for D-Day was fascinating; thanks for linking to it! Everyone else, if you are fascinated by Victorian brass machinery, WWII, and real-world applications of mathematics, you should read it.
posted by Triplanetary at 11:22 AM on October 17, 2011