Through The Sandglass

Icons old and deep

 
Thanks to Walter for bringing to my attention this particularly resonant and compelling image from the recent coverage of the investigation of a dramatic shipwreck in the Gulf of Mexico.

Here’s part of the original report from NOAA:

NOAA, BOEM: Historic, 19th century shipwreck discovered in northern Gulf of Mexico

May 16, 2012

  While most of the ship's wood has long since disintegrated, copper that sheathed the hull beneath the waterline as a protection against marine-boring organisms remains, leaving a copper shell retaining the form of the ship. The copper has turned green due to oxidation and chemical processes over more than a century on the seafloor. Oxidized copper sheathing and possible draft marks are visible on the bow of the ship.(Credit: NOAA Okeanos Explorer Program.)

During a recent Gulf of Mexico expedition, NOAA, BOEM and partners discovered an historic wooden-hulled vessel which is believed to have sunk as long as 200 years ago. Scientists on board the NOAA Ship Okeanos Explorer used underwater robots with lights and high definition cameras to view remnants of the ship laden with anchors, navigational instruments, glass bottles, ceramic plates, cannons, and boxes of muskets.

Equipped with telepresence technology, Okeanos Explorer reached audiences around the world who participated in the expedition through live streaming Internet video. As members of the public ashore watched live video from the ocean bottom, they became “citizen explorers,” sharing in the discovery with maritime archaeologists, scientists and resource managers from a variety of federal, academic, and private organizations.

The NOAA-funded 56-day expedition that ended April 29 was exploring poorly known regions of the Gulf, mapping and imaging unknown or little-known features and habitats, developing and testing a method to measure the rate that gas rises from naturally-occurring seeps on the seafloor, and investigating potential shipwreck sites.

The shipwreck site was originally identified as an unknown sonar contact during a 2011 oil and gas survey for Shell Oil Company. The Department of Interior’s Bureau of Ocean Energy Management (BOEM) requested this and other potential shipwreck sites be investigated during NOAA’s Gulf of Mexico expedition. Surveys and archaeological assessments are required by BOEM to aid in its decision-making prior to issuing permits for bottom-disturbing activities related to oil and gas exploration and development.

“Artifacts in and around the wreck and the hull’s copper sheathing may date the vessel to the early to mid-19th century,” said Jack Irion, Ph.D., a maritime archaeologist with BOEM. “Some of the more datable objects include what appears to be a type of ceramic plate that was popular between 1800 and 1830, and a wide variety of glass bottles. A rare ship’s stove on the site is one of only a handful of surviving examples in the world and the second one found on a shipwreck in the Gulf of Mexico.”

Significant historical events occurring in the regions around the Gulf of Mexico during this time include the War of 1812, events leading to the Texas Revolution, and the Mexican-American War, he said.

“Shipwrecks help to fill in some of the unwritten pages of history,” said Frank Cantelas, a maritime archaeologist with NOAA’s Office of Ocean Exploration and Research. “We explored four shipwrecks during this expedition and I believe this wreck was by far the most interesting and historic. The site is nearly 200 miles off the Gulf coast in over 4,000 feet of water in a relatively unexplored area.”

The news has been reported widely, these extracts being from CBS News and the Associated Press:

"When we saw it we were all just astonished because it was beautifully preserved, and by that I mean for a 200-year-old shipwreck," said Jack Irion, maritime archaeologist with the Department of the Interior's Bureau of Ocean Energy Management in New Orleans… Among the wreckage were "a rather astonishing number of bottles," particularly square gin bottles known as case bottles, as well as wine bottles, Irion said. There were many ceramic cups, plates and bowls that didn't appear to be cargo. Some were green shell-edged pearl ware, a British import popular in the United States between 1800 and 1830. The ship's kitchen stove was found intact. "Very few shipwrecks have been found that still have the stove intact," Irion said. "You can very clearly see the features of the stove. It's in rather good shape." Also discovered were an anchor, cannons and muskets. Irion said researchers have not yet determined whether it was a merchant, military or pirate ship… The wreckage can also give insight to the lives of the crew, where they had been, where they were going and their role in the economy and world history. "It's as if we get a glimpse into what their lives were like, like a time capsule," Irion said.

All kinds of fascinating stuff, but I can’t understand why no mention of the sandglasses lying in the sand…

A sad story of desert preservation

 
A story that appeared all over the news recently caught my eye for a number of reasons - here’s an example of the headlines: “Frozen in the sands of time: Eerie Second World War RAF fighter plane discovered in the Sahara... 70 years after it crashed in the desert.”

The Western Desert of Egypt and Libya is strewn with well preserved wreckage from WW II, but this is an extraordinary example. This is the BBC description:

A World War II RAF fighter, which crash-landed in a remote part of the Egyptian desert in 1942, has been discovered almost intact. There was no trace of the pilot, Flt Sgt Dennis Copping, but the British embassy says it is planning to mount a search for his remains.

The RAF Museum in Hendon, north London, says it is hoping to recover the plane as soon as possible.There are fears souvenir hunters will start stripping it.

The 24-year-old pilot, the son of a dentist from Southend in Essex, went missing over the Western Desert in June 1942, flying an American-made P40 Kittyhawk single-engine fighter. Two-and-a-half months ago an aircraft believed to be his was discovered near a remote place called Wadi al-Jadid by a Polish oil worker, Jakub Perka. His photographs show the plane is in remarkably good condition, though the engine and propeller have separated from the fuselage. The original paintwork and RAF insignia are said to be clearly visible, almost perfectly preserved in the dry desert air.

But of the pilot there is no sign. He appears to have executed a near-perfect emergency landing, perhaps after becoming lost and running out of fuel, and to have survived the crash. He rigged a parachute as an awning and removed the aircraft's radio and batteries but then apparently walked off into the desert in search of help. Almost 100 miles from the nearest settlement, he stood virtually no chance.

David Keen, an aviation historian at the RAF Museum, says the pilot broke the first rule of survival in the desert, which is to stay with your plane or vehicle. But the very same conditions which made the pilot's prospects so bleak have helped preserve the plane. Mr Keen says of the many thousands of aircraft which were shot down or crashed during the Second World War, very few survive in anything like this condition.

He said: "Nearly all the crashes in the Second World War, and there were tens of thousands of them, resulted on impact with the aircraft breaking up, so the only bits that are recovered are fragments, often scattered over a wide area. "What makes this particular aircraft so special is that it looks complete, and it survived on the surface of the desert all these years. It's like a timewarp."

The RAF Museum has a P40 Kittyhawk on display, but it has been put together from parts of many different aircraft.

Recovering Flt Sgt Copping's plane will not be easy. It is in a part of the desert which is not only remote but also dangerous, because it is close to a smuggling route between Libya and Egypt. The defence attache at the British Embassy in Cairo, Paul Collins, says he is hoping to travel to the area in the near future, but is waiting for permission from the Egyptian army.

He told the BBC: "I have to go down there. This is a serviceman who was killed, albeit 70 years ago. We have a responsibility to go and find out whether it's his plane, though not necessarily to work out what happened. He went missing in action. We can only assume he got out and walked somewhere, so we have to do a search of the area for any remains, although it could be a wide area. But we have to go soon as all the souvenir hunters will be down there." 

He said the British authorities are trying to find out whether Flt Sgt Copping has any surviving close relatives, because if his remains are found a decision will need to be made about what to do with them.

A compelling story. And, of course, being a geologist and having spent some time in the Western Desert, I was curious – where, exactly, was the plane found? The location mentioned, Wadi al-Jadid, is a very large area south and west of the village of Mut, part of the sprawling oasis of Dakhla – through which I had passed, travelling to the southwest on my way to the Gilf Kebir several years ago. Geologists have a strange tendency to look at the rocks in a photo or in a movie (and, unnervingly for passengers, out of the car window while driving), and an examination of the photos above reveals a couple of things. First, all the gumph in the press reports about “buried in the sands of time” is exactly that – this is an area of sand-blasted limestone outcrops across which the blasting grains would bounce, swirl, and keep going: no dunes deep enough to have buried the plane could accumulate there. Second, the reports variously describe the location as being one hundred or “more than 200” miles from the nearest town, which is, perhaps, Mut. Vast areas to the south and west of Mut are covered by dunes sweeping across seemingly endless gravel plains – few outcrops,none of them limestone. Only after around 150 miles did we enter the distinctive blasted limestone landscapes. I would suggest that this image from my trip is evocative of the general environment shown in the photos of the plane:

I have no intention of providing a guide to bounty-hunters – the area shown on the Google Earth images below is still huge (and, anyway, I may be wrong - I am, see comment discussion below after this was posted):

And there is other scattered WWII wreckage strewn through this part of the desert:

The desert preserves, dramatically and effectively, with or without sand. From elsewhere on that trip are some further examples (the unopened can of sliced bacon, and the battery are from the 1930s):

Incidentally, the comment in the BBC piece that the area is “also dangerous, because it is close to a smuggling route between Libya and Egypt” I believe is somewhat misleading. Those photos come from the desert west of the Gilf Kebir and it is there, along the Libyan border, that certainly the main people smuggling routes run – I know (and wish that I didn’t), because we saw some of the trucks in the distance.

The CNN report describes how “The young pilot, according to [British military historian] Saunders apparently became disoriented during the flight and headed in the wrong direction. Another RAF pilot flying nearby ‘tried all sorts of things’ to get his attention, but Copping ‘bizarrely’ ignored a series of warnings.” So where should the pilot have been trying to get to? The Imperial War Museum website proves to be yet another wonderful internet resource. Here are two images from their online archives of the North African Campaign:

Left, “A Curtiss Kittyhawk Mark I of No. 112 Squadron RAF taxies through the sand at a landing ground in the Western Desert. A mechanic sitting on the wing is guiding the pilot, whose forward view is obscured by the aircraft's nose.” Right, “Trolleys loaded with 250-lb GP bombs are drawn up in front of a line of Curtiss Kittyhawk Mark IIIs of No. 260 Squadron RAF at Marble Arch landing ground, Libya, prior to a bombing sortie.” (Reproduced courtesy of the IWM Non-Commercial Licence).

 

These landing grounds were scattered across the Western Desert, but, appropriately, close to the Mediterranean coast; the Google Earth image above shows one of the British-American joint bases, RAF Gambut, from which the Kittyhawks flew. The pilot of this one was certainly, tragically, a long way from home.

 

 

 

 

Tom, Dick, Harry, and George - sand and The Great Escape

 

The plan to dig down to the workshop at the starting point of the tunnel known as Harry, where the wartime fliers began their effort to tunnel beneath the barbed wire, was aborted when engineers failed repeatedly to prevent tons of sand from collapsing their own access tunnel.

“The tunnel known as Harry” was one of the incredible constructions by the prisoners of Stalag Luft III, the escape tunnels, laboriously and ingeniously built, that would be immortalised in the movie, The Great Escape. But this story did not need a movie for immortality – it was extraordinary enough in reality. And now a geoarchaeological project, led by Hugh Hunt, a Cambridge University engineering professor, has shed further light on just how extraordinary it was.

The prisoner of war camp was built, intentionally, on the sandy soils of the forests of today’s western Poland, along the banks of the Bóbr river. Intentionally, because the river valley is filled with sandy sediments deposited from melt waters of the Ice Age glaciers and carried by the ancestral Bóbr. And sand is difficult to tunnel through. Very difficult.

An earlier geoarchaeological expedition to the site of Stalag Luft III was reported in a fascinating article by Peter Doyle and his colleagues that includes a geological assessment of these soils. The following illustration of the sands is taken from their work:

A thin grey organic soil is underlain by glacio-fluvial cross-bedded sands, yellow and reddish-yellow in colour. As the authors point out, this in itself was a problem for the would-be escapers – the excavated sand from the tunnels was immediately visible if deposited against the darker topsoil.

There were numerous tunnelling attempts made at Stalag Luft III, each tunnel given a name, but the events captured in The Great Escape related to Harry. Harry was 330ft long, made from 4,000 bed boards and dug with thousands of pieces of cutlery. The ingenuity and engineering were astonishing – and, as Hunt discovered, impossible to reproduce without unacceptable danger. The movie was based on the book of the same name by Paul Brickhill, whose illustration of the project was reproduced in the article by Peter Doyle and his colleagues:

 
The escape would end in tragedy for all but three of the 76 prisoners who emerged from the tunnel on that March night in 1944. “Following the escape, it is estimated that 5 million Germans were mobilized to recapture them. Of the 76 that escaped, 3 eventually reached Allied territory, but the remainder were recaptured, and 50 of them were executed by the Gestapo.”

One of the remarkable details of Hugh Hunt’s recent project was that one of the team was Frank Stone. Now 89, Frank was waiting his turn to enter the tunnel that night when the escape was discovered. As reported in the Daily Mail, he demonstrated the use of the trolleys made to move men quickly down the tunnels:

Memorials now mark the sites of the entrance and exit to Harry:

 
Hunt’s work was the subject of a recent documentary on British TV, and compellingly described in the following piece from The New York Times:

Latter-Day Dig of ‘Great Escape’ Tunnels Humbles Modern Engineers

By JOHN F. BURNS

CAMBRIDGE, England — For scale, they were no match for the Great Pyramids of Giza or the Panama Canal. The labor took months rather than years and a work force of barely 100 men. As for materials, there were none, beyond what the captured Royal Air Force fliers who built them could scavenge, scrounge or improvise.

But by the measures of ingenuity, courage and persistence, the tunnels built almost 70 years ago in sandy scrubland near the small town of Zagan, 130 miles southeast of Berlin in what was then Hitler’s Germany and is today western Poland, were a legendary feat of engineering, although on a miniature scale.

Chronicled by the 1963 movie “The Great Escape,” the tunnel building is one of World War II’s great stories. In the decades since, the legend of the allied fliers’ mass breakout on the night of March 24, 1944, together with the ingenious planning and the Nazi retribution that followed — 73 of the 76 escapers recaptured, and 50 of them summarily executed on Hitler’s orders — has, in a way, eclipsed reality.

In an effort to establish more clearly how the escape was accomplished — and, in a sense, to reclaim the narrative of the breakout — British-based engineers, battlefield archaeologists and historians traveled into the pine forest outside Zagan last summer to unearth the secrets buried there for a television documentary by Wildfire Television in London that was broadcast in late 2011 in Britain. They were accompanied by modern-day Royal Air Force pilots, as well as veterans of wartime bombing raids, now in their 80s, who helped build the tunnels at the encampment known as Stalag Luft III.

The team’s task was to employ “reverse engineering” by uncovering the tunnels and what remained of the tunnelers’ jury-rigged equipment to replicate the wartime fliers’ ingenuity. Ultimately, the team members were stunned that, even without the menace of the ever-watchful Nazi camp guards, they were unable to match their wartime counterparts fully, particularly in the most crucial skill, digging a tunnel 30 feet below the camp surface without repeated collapses of the sandy soil above.

For years, veterans and others have pored over the camp’s ruins, laying memorial stones amid the outcroppings of broken brick and concrete scattered among the pine trees, all that remains of the 60-acre site built by the Germans to house 10,000 captured fliers. But no group matched the expertise of the 2011 team, which went determined to lay bare what Hugh Hunt, a Cambridge University engineering professor, described as “the final secrets of a remarkable story.”

A maverick Australian affectionately nicknamed Dr. Screwloose by his colleagues, Dr. Hunt went to Poland as a consultant to the current R.A.F. pilots, including some with combat experience over Iraq and Afghanistan. Their task was to use insights gleaned from the digs at the sites of wartime tunnels known as Harry and George to build a new 35-foot tunnel they called Roger, after Squadron Leader Roger Bushell, the principal organizer of the 1944 escape and one of those executed by the Nazis.

“What those men did at Stalag Luft III was an astonishing feat of improvisational engineering,” Dr. Hunt, 50, said in an interview at Cambridge’s Trinity College. “Their resourcefulness was beyond belief. It wasn’t a case of one man’s genius, more the accomplishment of a team, one man’s skills complementing another’s. And they had one precious resource, time. If you have time, somebody will eventually come up with something, and the others will say, ‘Let’s give it a go.’ ”

Like others who joined in the expedition to Zagan, Dr. Hunt has little quarrel with the escape story as told in the film version, which was based on Paul Brickhill’s book of the same name, partly because the tunnelers’ real-life drama required little embellishment. The wartime camp, for one thing, did not have a Virgil Hilts, the irrepressible American flier played by Steve McQueen, and there was no climactic sequence like his flight from German troops on a stolen BMW motorcycle and entanglement in a border fence, one of cinema’s great chase sequences.

The plan to dig down to the workshop at the starting point of the tunnel known as Harry, where the wartime fliers began their effort to tunnel beneath the barbed wire, was aborted when engineers failed repeatedly to prevent tons of sand from collapsing their own access tunnel. But Dr. Hunt and his team struck gold in the excavation of George, a tunnel built under the camp auditorium after the escape and designed to give inmates a place to hide as Nazi control east of Berlin collapsed before advancing Soviet troops.

Their dig yielded a set of rusting trolley wheels, the metal scavenged from remnants of a campsite stove and a coil spring taken from prison gramophones; wood paneling for the tunnel’s roof and sidewalls, fashioned from the prisoners’ bed boards; and a ventilation pump with a bellows and piping made from a prisoner’s kitbag, ice hockey sticks and tins of powdered milk. The pièce de résistance was a rusting radio made from a biscuit box, the wiring stolen from the prisoners’ huts and batteries scrounged from German guards.

The contemporary Royal Air Force fliers built Roger, the replica tunnel, but in a trench just beneath the surface; anything deeper was deemed too dangerous. With Dr. Hunt, they fashioned a trolley system, given its first run in the new tunnel by Frank Stone, 89, a camp veteran involved in preparing the 1944 escape plan. The 2011 team also built a replica of the original tunnelers’ ventilation system, with facsimiles of wartime milk tins and a World War II kitbag.

Mr. Stone, maker of the biscuit-tin radio found in the excavated remains of tunnel George, was one of those still waiting for his turn to escape when a German guard spotted one flier scrambling from the tunnel exit into the pine trees. He remained a prisoner until the camp was liberated in 1945, with a lifetime to grieve for the men who made it, if only briefly, to freedom. “People say to me, ‘How unlucky you were,’ ” he told the documentary makers. “But I say, no, I was lucky to have taken part in it at all.”

 

[Memorials images Lech Muszynski/European Press Photo Agency and http://www.raf.mod.uk/project104/gallery/stalagluftiiigallery.cfm?viewmedia=3]

Extraordinary women–and a Gobi sand question

 
For one reason or another, I have been reading The Gobi Desert by Mildred Cable and Francesca French. In the history of exploration and enquiry into far-flung parts, it’s easy to overlook that regiment of indefatigable women – particularly Victorian - who played extraordinary roles. Perhaps the most celebrated was, of course, Gertrude Bell, whose middle-eastern exploits changed politics and history. But in China, in the first couple of decades of the last century, there were three women, Mildred, Francesca, and the latter’s sister, Eva (Evangeline), who documented the landscapes and culture of that part of the world through quite remarkable travels. Yes, they were missionaries, but they pursued their goals with linguistic skills and a deep cultural sensitivity that resulted in accounts that are distinctly and fascinatingly different from the typical travel writing of the times and have become classics. And the classic of the classics is their description of their thirteen years in the Gobi, “following trade-routes, tracing faint caravan tracks, searching out innumerable by-paths and exploring the most hidden oases. ... Five times we traversed the whole length of the desert, and in the process we had become part of its life."

The story begins as they set out from the fort at what is today called Jiayuguan, the westernmost bastion of the Great Wall. Leaving the western gate, they passed a great mound of earth whose role was to keep out the evil spirits of the desert, and a stone tablet on which were inscribed the forbidding words “Earth’s Greatest Barrier.” Following the Silk Road westwards, they stopped at isolated and insular oases – Shachow, “City of Sands,” Shamen, “Gates of Sand.” These even before they reached the Taklamakan Desert proper.

But one of the things that intrigues me is the following account from their overnight stay in Huei-huei-pu, the “Moslem Tomb Halt,” whose location today I have yet to figure out. While wandering around the village, Mildred stopped at the local shop, where

There was something different here, however, for, in addition to the dull stock of the oasis shopkeeper, this man had a variety of articles made from a fine-grained, light-grey stone which was found near at hand. These were slabs on which to rub down the hard sticks of Chinese ink, and little pots to hold water with which to moisten them. The chief demand, however, was for small pieces to be used as whetstones for knives, razors or scissors, and many a carter passing that way added a hone to his small outfit of traveller’s necessities.

Having made some purchases, Mildred sat down and chatted with the shopkeeper about this and that, but then

I turned to go, and just as I was leaving, I noticed on his counter a jar of coarse grey sand. Taking some of it in my hand, I rubbed it between my fingers testing the quality of the grains, and as I did so I felt there was something unusual about it. “What do you keep sand for?” I asked. “Is there not enough of it by the roadside?”

“This is special sand, Lady,” he said. “It comes from near here but is not found elsewhere in the Gobi.It is so heavy that the wind does not blow it about, and it is the only sand which can be used for one process in the polishing of jade.Though it is hard enough to use even on jade, yet it never scratches the surface. It is very highly valued, and jade polishers send here to get it.”

So there’s my question – does anyone have an idea as to exactly what this highly valued sand might be?

Sunday sand: Ngrayong

Tectonic turmoil has been a long-running production in Indonesia, even by geological measures. Thirteen million years ago, peaceful seas covered what is today eastern Java, but blundering plates soon put an end to the tranquillity. The entire island of Borneo was rotating counter-clockwise, at the same time suffering upheaval to the point where erosion became rapid and relentless. Huge volumes of quartz-rich sands cascaded southwards into the seas of East Java, burying the old, calm, seafloor in a thick blanket of shallow marine and deepwater sands and mud. Eventually, the seas were entirely filled with these sediments and rivers and deltas dominated what had been a marine environment.

Continuing upheaval would eventually raise these sediments back above sea level and expose them as sandstones in the river banks of eastern Java. They are on particularly fine display not far from the village of Ngrayong which gave its name to this particular pile of sedimentary archives. The grains of the Ngrayong sandstones are remarkably immature – they are sharp-edged and angular, their journey having been too short for any effective abrasion and rounding of those rough edges.

All of the grains in the images above are less than a fifth of a millimetre across, very fine-grained components that have been separated from their coarser companions by sieving. Why separate out these grains? Well, I came to have a bag of this Ngrayong sand not because I have visited the location, but because I was visiting the siever, so to speak; it turns out that these grains perform particularly well in a rather intriguing experimental application – but more of that for another post.

Where still buried underground, the Ngrayong sandstones themselves have also performed rather well for more than a century as a reservoir for oil and gas. The original discoveries were made by the Dutch in the days of colonisation; I did visit these old fields many years ago when I was in Indonesia before, for they are still producing and more discoveries, some of them very large, are still being made. But the real fascination was the in situ museum of industry history that the area represented – pieces of old equipment, venerable wheezing pumps and groaning fly-wheels still sedately in action. Unfortunately, all those photographs are in my archives back in London, but here are a couple of images from the 1920s, courtesy of the Tropenmuseum in the Netherlands. 

 

Military forensics: a reader's query

 
I have frequently noted my pleasure in regularly receiving “out of the blue” comments and e-mails – I find myself in contact with all kinds of people from around the world with whom I would never have otherwise intersected, on an amazing range of topics, many of which are completely new to me. All of this because of a mutual interest in all things arenaceous.

Here’s a case in point – together with a question for anyone who might be able to shed light on this. The unique nature of any particular family of sand grains from a specific location, be it a river sand bank or a coastal beach, has long provided forensic science with a tool for location identification. This has not only been applied to any number of cases of criminal forensics, but also, for example, to archaeological and military investigations. I described the classic military example in Sand:

In late 1944, balloons 9 meters (30 ft) in diameter appeared in the skies above the United States. Landing from the West Coast to Michigan, they carried a deadly cargo: incendiary bombs. Although the only casualties over the following months were, tragically, members of a Sunday school group attempting to retrieve one that had landed, the potential danger to life, towns, and forests was considerable. It was apparent that the weapons had blown in from the Pacific, but where had they been launched? The devices had an automatic altitude-regulation system, releasing hydrogen or ballast to maintain height. The ballast bags were filled with sand. The U.S. Geological Survey’s Military Geology Unit, established in 1942, was tasked with identifying the sand. The family of grains was consistent from one retrieved ballast sample to the next, and unique. Distinctive forams and other microscopic shells, together with small amounts of unusual mineral grains in among the granite debris, correlated precisely with beach sands described in prewar geological reports from two locations on the east coast of Japan. Air photographs identified hydrogen production plants at these locations, which were then targeted and destroyed.

Recently, a reader of this blog, a self-confessed “WWII history buff” sent me a series of photographs and asked for my views on whether there was any chance of figuring out the provenance of the sand grains shown at the head of this post. And where did these grains find themselves used as a military application? As camouflage on a German helmet:

The military unit would seem to be a naval artillery group, and France would be the likely origin. But does anyone have any ideas as to a more specific location?

Sunday Sand: grains of tragic truth, June 6, 1944

In Sand, talking about the genetic history of families of grains, I wrote the following:

A traveler expects to sample a local cuisine that has its origins in local ingredients, and it’s no different with sand. Relaxing on a beach in North Carolina or the south coast of England, looking at the sand between your toes, you would hardly expect it to be made of bits and pieces thrown out of a volcano. Trekking along the coast of Greenland, you would be surprised if the sand were composed of the debris from a coral reef. What you do find are sand grains of predominantly local parentage. On the Normandy beaches where D-day landings took place, you will find sand-sized fragments of steel.

In 2009, for the first time, I visited the Normandy beaches – and the memorials and the cemeteries – and posted a brief report in September last year. I mentioned again the fragments of steel, shrapnel sand grains, but have never convincingly located any in the samples that I have looked through. Now the latest issue of Earth Magazine carries an article titled “D-Day's Legacy: Remnants of invasion linger in beach sand.” In it, two sedimentary petrologists, Earle F. McBride and M. Dane Picard, describe their visit to the D-Day beaches and the analysis of the sands from Omaha after their return to the laboratory – “Little did we know what we would find when we got home and started studying the sand.”

 A thin section of the sand revealed a large number of angular opaque grains that were magnetic. Shard-like, they were only slightly rounded. Some were well-laminated. These grains were also associated with small spherical beads of iron and glass. At first, we were uncertain of what we were looking at. However, in a few days, we concluded that the metal and glass particles were human-made — particles generated from the explosions of munitions during the Normandy landings. After further testing, we determined the sand does indeed contain 4 percent shrapnel and trace amounts of beads of metal and glass. Because waves and currents on any given day can selectively concentrate sand grains of a given specific gravity, we cannot be certain that our sample is representative of the entire beach — that shrapnel grains make up 4 percent of Omaha sand as a whole.

They go on to describe the likely origin of the glass grains as being from explosions in the sand – with the critical contribution of seawater salts as a flux that lowered the melting point of the quartz. Read the whole article, it’s well worth it.

So tomorrow, we remember – please – the events of that day in 1944. And perhaps should you visit those broad calm beaches as they appear now, think of that granular legacy, those witnesses beneath your feet. 

Sunday Sand: A Kefalonian Kaleidoscope - and Homer (not Simpson)

Location, location, location. Ingredients, ingredients, ingredients.

Just look at these two sands, and the words ring true – one is from the Greek Ionian Island of Kefalonia – or Cephalonia (or  Cephallenia, Cephallonia, Kefallinia, or Kefallonia) – the other from neighbouring Ithaki. The beaches of Kaminia (top, Ithaki)) and Xi (lower, western Kefalonia)) are perhaps thirty kilometres apart, but one faces the mainland, the other the open sea; one is backed by limestone cliffs and mountains, the other by lower agricultural terrain (albeit still built on limestone). And one has red-brown sand, the other whitish grey. Through some conspiracy of microclimate, topography, and geochemistry, the hinterland of the beaches at Xi is covered in lateritic soils, the grains coated in iron minerals, the landscape a patchwork of rust and white. At Kaminia, the more sheltered waters play host to biological activity, and the sands contain abundant shells of foraminifera and other critters.

 
And, while we’re in this particular part of the world (famous, of course, for Captain Corelli and his mandolin), there’s a bit of a mystery associated with these islands. “Ithaki” – must be the land that featured so prominently in Homer’s Odyssey, surely? But there’s a problem – Homer’s description doesn’t fit with today’s geography. Homer lived far away from, and long after, the locations of the saga of Odysseus; in the Iliad, he described the people of Ithaca as “the gallant Cephallenians,” yet today’s island of Ithiki is distinct from Kefalonia. Furthermore, when Odysseus describes his homeland, he states that, of the group of islands, “Ithaca itself lies low, furthest to sea towards dusk; the rest, apart, face dawn and sun.” A glance at a map shows Ithiki to the east, certainly not furthest to the sea towards dusk – it would seem to be “one of the rest,” facing the dawn.

Now, the fact is that these islands lie in a region of daily tectonic exercise; minor earthquakes are constant, major ones common. Is it possible that thousands of years of this activity have wrought significant changes to the landscapes of the islands? Go to http://www.odysseus-unbound.org/index.html, and you can read the fascinating story of a geological project that attempts to answer this question: “But can earthquakes change the layout of entire islands? That was the challenge facing the exploration team in 2003. It has taken intensive efforts and the advice of experts from all over the world to answer this question. We now know that the answer is a resounding 'yes'.” Specifically, is it possible that the low-lying valley, shown on the map as “Strabo’s Channel,” and which separates the western peninsula of Paliki from the rest of the island, was once a seaway? Have landslides and erosion caused by repeated earthquakes filled in this channel?  If this were the case, then Paliki was once an island and fits with Homer’s description of Ithaca. (The map is taken from the website, and the original labels Paliki as “Ithaca” – I removed this in the interests of avoiding prejudice).

The geological and geophysical work on the project has been led by John Underhill, Professor of Geology at the University of Edinburgh and an old friend. The account is fascinating, so have a browse around “Odysseus Unbound” and see what you think.

If only Homer had described the sands of the beaches along which his “gallant Cephallenians” lived, the mystery might be more easily solved.

 

[Thanks – yet again – to Carla for the sand samples.]

Ignoring tsunami records: hubris, complacency, or just human nature?

The earthquake that struck Japan may have been the largest since historical records began (and the fourth largest ever recorded), but the tsunami had many precedents – bigger ones – in the historical and geological record. The size of a tsunami is related to the displacement of the seafloor, not necessarily the magnitude of the earthquake, and significantly smaller events than the one on March 11th have generated larger tsunamis. This raises two questions: given the size and devastation of past events, why should this have been a surprise and why were “defences” so woefully inadequate? And, are there, realistically, such things as “tsunami defences” at all?

These are questions that countries beyond Japan should also be asking themselves.

I have put off writing anything about the catastrophe, in part because the geoblogosphere has been doing its typical comprehensive job (see Dana Hunter’s links as a good starting point), but also because I was, I suspect like many of us, simply mesmerised by the surreal and incomprehensible scenes that unfolded, day after day, through the unprecedented documentation of the tragedy. But now I have begun reflecting on one of my earliest posts, “Tsunami forensics - sand helping save lives,” and concluded that we would seem to have a long way to go; if hubris, complacency, and other human foibles led to a failure of thinking and planning in Japan, then where is the hope for less developed (or even equally developed) parts of the world?

First of all, following up on the theme of my post on the forensics of sand deposits documenting past tsunamis in Thailand and Sumatra, I easily located a couple of examples of the same kind of work that has been conducted, hardly surprisingly, in Japan. In their article, “Geological Study of Unusual Tsunami Deposits in the Kuril Subduction Zone for Mitigation of Tsunami Disasters,” Japanese researchers describe meticulous analysis of tsunami sand deposits covering the last 5,000 years from Hokkaido, north of the recent events; the sands are carefully dated, and their internal structures used to shed light on the flow regime of the tsunamis that deposited them. They observe that “Only when an unusual tsunami strikes coastal lowlands does a large-scale sediment transfer occur, leaving a sedimentary record, that is, tsunami deposits, in the geological strata on shore.” And they calculate, from the multiple tsunami sands preserved, the average recurrence interval of “unusual tsunamis”: every 220-379 years over the past 5,000. They conclude that “The geological information obtained by this study is valuable for mitigation of tsunami disasters.” Well, maybe.

 
Similar recent studies have been done in other areas of Hokkaido. For example, “Aperiodic recurrence of geologically recorded tsunamis during the past 5500 years in eastern Hokkaido, Japan” (only the abstract is publically available) documents that “The sand sheet extents suggest that most of these tsunamis were larger than any generated at Hokkaido in the last 200 years. The intervals between these inferred outsized tsunamis average nearly 400 years but range widely from about 100 to about 800 years.” Bear in mind these intervals – 100 to 200 years are entirely possible – in the context of historical events. 

Of course, I couldn’t help but be curious about a paper with the title “A Huge Sand Dome Formed by the 1854 Earthquake Tsunami in Seruga Bay, Central Japan.” This is a geological study of tsunami sand deposition as a result of a historically documented event. Seruga Bay is not far south of Tokyo, and the 1854 tsunami was devastating; here’s the abstract of the paper:

The 1854 Ansei-Tokai earthquake brought massive destruction to Suruga Bay, central Japan. The earthquake triggered a large-scale tsunami, which surged over the Pacific coast of Japan. Waves exceeding 13.2 m in height attacked Iruma, southeastern coast of Suruga Bay, and provoked peculiar types of tsunami sedimentation. On the coast of Iruma, a huge mound of shoreface sand, reaching more than 11.2 m above sea level, appeared after the tsunami run-up. We performed a historical and sedimentological survey to clarify the origin of the mound. Result of a field excavation and submarine
investigation suggests that the sand came from the seafloor with a water depth of 20 to 30 m, and historical data illustrates a dramatic change of the landform by the tsunami run-up. Numerical examination of the tsunami implies that the coastal topography played an important role in excitation of the tsunami, and it induced the characteristic tsunami sedimentation.

“Waves exceeding 13.2 meters.” Here’s the town of Iruma today, completely rebuilt on top of this gigantic pile of sand:

Mass transfer of sediment by a tsunami causes wholesale changes to coastal topography, and when the shape of the coast resonates with, and amplifies, the character of the tsunami wave, the effects can be dramatic. Among the compelling images of the last ten days are the series of “before and after” images, of which fascinating (and depressing) examples are from the New York Times and Picasaweb. Any number of these illustrate coastal change and the shifting of huge amounts of sand. Here, for example, the coast near Ueda, south of Sendai:

But this is only part of the story of coastal change. The wholesale physical displacement of Japan as a result of the earthquake is, even to a geologist, astonishing. Callan Bentley reported GPS data showing a lateral movement of 4.4 meters and he points out the less widely reported, but in many ways more significant vertical subsidence of up to 75 cm along some parts of the coast. But now, as if these figures weren’t dramatic enough, Japan’s Geospatial Information Authority in Tsukuba are reporting that the Oshika Peninsula that lies closest to the epicentre has moved 5.3 meters and dropped 1.2 meters since the earthquake – records for Japan. Scrutinise the before and after images, and evidence of coastal subsidence as well as erosion, becomes apparent. Consider these images of the Yamamoto coast, not far from Sendai:

 
But, for me, the greatest drama is apparent in images from the area of Ofunato and Otomo, a hundred kilometres north of the Oshika Peninsula:

Look closely and compare – the entire coastline appears to have sunk (even allowing for the fact that the relative state of the normal tide in the two images is unknown). The town of Otomo is at the left in each image; a seawall is apparent across the bay “before,” but has completely disappeared – and would seem to be buried in sand – in the post-tsunami image. The devastation in these towns was almost total and rescuers are still struggling to even access them. Here’s another pair of images – are we seeing an enormous sand deposition event similar to that at Iruma in 1854? Was there also a resonance between the shape of the coastline and the tsunami that amplified the potential for catastrophe?

 
That potential for catastrophe certainly becomes greater if the subsidence of the coast as a result of the earthquake is taken into account. A seawall, such as that supposedly protecting Otomo, instantly drops by a meter, its height rendered even less effective against an unusual tsunami. And it’s not as if this stretch of coast had not experienced “unusual tsunamis” before – you don’t even have to dig into the geological record. In 1896, an earthquake whose magnitude is estimated as 7.2 – in other words, not at the worst end of the scale – caused a reported 25 meter tsunami. And the 1933 8.4 magnitude earthquake caused a tsunami described as 28 meters high. The scale of a tsunami is very much dependent on the shape of the coast, not necessarily the magnitude of the earthquake.

The recorded history of Japan’s coast is filled with accounts of “unusual tsunamis” – David Bressan has an excellent summary. Look into the sedimentary record, and the evidence continues: around Sendai, five tsunami sands are found up to four kilometres inland; along the coast near Ofunato and Otomo, up to 113 sand layers record major tsunamis – some of them from elsewhere in the Pacific. These figures come from the presciently titled book by Edward Bryant, Tsunami – The Underrated Hazard (published in 2001 and now extremely expensive, but available on Google books). As Bryant writes, “the stratigraphic evidence designates this coastline as the most frequently threatened inhabited coastline in the world.” Indeed.

So how, when the historical and geological evidence shows so clearly that devastating tsunamis hit a sinking coastline with a frequency that hardly labels them as “black swans,” could such a catastrophic loss of life – not to mention a nuclear emergency - as we have been witnessing possibly occur?

There is, clearly, no simple answer, but part of the problem would seem to be a level of complacency that is not, unfortunately, atypical of human nature. Take the seawalls, for a major example. As a piece in the New York Times reported, “At least 40 percent of Japan’s 22,000-mile coastline is lined with concrete seawalls, breakwaters or other structures meant to protect the country against high waves, typhoons or even tsunamis. They are as much a part of Japan’s coastal scenery as beaches or fishing boats, especially in areas where the government estimates the possibility of a major earthquake occurring in the next three decades at more than 90 percent, like the northern stretch that was devastated by Friday’s earthquake and tsunami.” But the article goes on to say:

A fuller picture of how seawalls protected or failed to protect areas beyond the nuclear plants will not emerge for at least a few more days. But reports from affected areas indicate that waves simply washed over seawalls, some of which collapsed. Even in the two cities with seawalls built specifically to withstand tsunamis, Ofunato and Kamaishi, the tsunami crashed over before moving a few miles inland, carrying houses and cars with it.

In Kamaishi, 14-foot waves surmounted the seawall — the world’s largest, erected a few years ago in the city’s harbor at a depth of 209 feet, a length of 1.2 miles and a cost of $1.5 billion — and eventually submerged the city center.

“This is going to force us to rethink our strategy,” said Yoshiaki Kawata, a specialist on disaster management at Kansai University in Osaka and the director of a disaster prevention center in Kobe. “This kind of hardware just isn’t effective.”

We are all now numbed by the videos of the tsunami not only crashing over seawalls, but destroying them – videos taken by residents who may well have assumed that they could remain, protected by those defences, residents who were lucky to have survived. And then look at the before and after images of Otomo, above: a seawall not only rendered useless, but consumed.

Again, from the New York Times article: 

The height of seawalls varies according to the predictions of the highest waves in a region. Critics say that no matter how high the seawalls are raised, there will eventually be a higher wave. Indeed, the waves from Friday’s tsunami far exceeded predictions for Japan’s northern region.

And, for a mind-numbing example of tragic complacency, watch this BBC video of the Fire Chief of the town of Rikuzentakata, just SW of Ofunato, describing how a tsunami two years ago damaged the seawall. His warnings went unheeded, and, on the 11th March, 45 of his crew were lost trying to close the harbour gates by hand.

I simply don’t understand how, given even the sampling of historical and geological records above, what the “predictions” that were "far exceeded" could possibly have been based on, and how there could have been the total lack of imagination that allowed them to be regarded as definitive. And then there’s the reliance on the – tragically inadequate – seawalls protecting the nuclear power plants. Couldn’t someone, even years after the construction of the plants, have said, in the spirit of over-engineering where failure could have catastrophic consequences, “There is a scenario, not impossible to conceive, in which the seawalls would fail – just to be safe, why don’t we put our generators and pumps, the switchboards and backup systems, on top of an impregnable fifty-foot reinforced concrete structure?” Or something to that effect.

Maybe I’m over-simplifying things, maybe not….

Update: since I wrote this post, I have been in touch with my geologist friend, Rovicky (who writes his own blog on these kinds of things and many other matters geological - in Indonesian) and he provided me with yet another paper on reconstructing ancient Japanese tsunamis from sand deposits. This is from studies of the Sendai area, one focus of recent devastation. Titled "The 869 Jogan tsunami deposit and recurrence interval of large-scale tsunami on the Pacific coast of northeast Japan," the abstract is as follows:

The fore-arc region of northeast Japan is an area of extensive seismic activity and tsunami generation. On July 13, 869 a tsunami triggered by a large-scale earthquake invaded its coastal zones, causing extensive deposition of well-sorted fine sand over the coastal plains of Sendai and S ma. Sediment analysis and hydrodynamic simulation indicate that the tsunami inferred to be triggered by a magnitude 8.3 earthquake spread more than 4 km inland then coast. We postulate that the sand layer was developed by the tsunami’s first wave. Traces of largescale invasion by old tsunami as recorded in the coastal sequences of the Sendai plain show about a 1000-year
reoccurrence interval. We suggest that the J gan tsunami was much larger than tsunami generated by normal earthquakes in the subduction interface.

The paper would normally be available online from the Japanese National Institute of Informatics, but at the moment, the site sadly simply contains the following note: "NII services is currently unavailable due to a scheduled blackout in connection with the Japan earthquake. Sorry for your inconvenience." If anyone is interested, I can email a pdf, thanks to Rovicky.

 

[For an interestingly different approach to tsunami shelters, and other approaches, see this report from the New Scientist. And for further reading on earthquake and tsunami - and general - hazard assessment, see http://blogs.agu.org/landslideblog/2011/03/15/from-a-geological-perspective-what-is-surprising-about-the-sendai-earthquake/. For a mesmerising display of the - at the time of writing - more than 600 aftershocks, visit http://www.japanquakemap.com/]

 

Snot's troglodytes and rifting continents

 
I was born in Nottingham – some time around the late Pliocene: there’s a plaque somewhere, I’m sure. Nottingham is an old city, founded in Saxon times, when it was known as Snotengaham, the place where Snot’s people lived; it was strategically sited on sandstone bluffs overlooking the river Trent and the Norman invaders would later build their castle there. The city is, of course, best known for the legend  of Robin Hood and his merry men (and, presumably, women), and draws many visitors for that reason. But the castle today is a relatively modern affair (see the bucolic print below, from 1776) and Robin Hood is a brand more than anything else. However, the inquisitive will find evidence of real history that is far more tangible – centuries of excavation into the sandstones beneath the city.

I remember as a kid the famous “Trip to Jerusalem” pub and its rooms and caves carved back into the rock; and the history of the city’s caves came with all the dire, dark, and bloody stories that kids love – dungeons and death, mysteries and evil-doing. Evidence of the subterranean maze can easily be seen from the outside today, entrances in the cliffs frustratingly closed by locked doors and metal grills.

 
This man-made cave system, space hewn from the rock, has developed over the centuries because the sandstone is relatively poorly cemented and easily excavated. At least since Mediaeval times, tunnels and rooms have been carved out for a vast array of purposes, including dungeons, beer cellars, cess-pits, tanneries, malt-kilns, houses, wine cellars, tunnels, summer-houses, air-raid shelters, sand mines, follies, dovecotes and, for while during WWII, the storage of radium. Temperatures underground remained constant and cool, making for ideal conditions for brewing and storing ale – the Mediaeval malt kiln below is an example of the year-round brewing facilities that made Nottingham famous for its beer (a reputation sadly much-diminished).

 
The known extent of this subterranean infrastructure probably only represents a fraction of the entire system, and now a project to survey and map the caves is well-underway, superbly documented on the project website - “The Nottingham Caves Survey is the first part of the Caves of Nottingham Regeneration Project (CoNoRP). This is a two-and-a-half year project funded by the Greater Nottingham Partnership, East Midlands Development Agency, English Heritage, the University of Nottingham and Nottingham City Council. The project intends to take a fresh look at Nottingham’s caves and encourage the City and its visitors to appreciate the caves for the unique historical resource they are.” The survey is based around the wonderful technology of 3D laser scanning, described on the website:

Laser scanners come in a variety of forms but they all work in a similar way. The scanner fires out a beam of laser light which reflects back from the first thing it hits. The instrument measures the amount of time it takes for the light to return, and from this can calulate how far away that object is. The scanner then rotates the beam a little, and takes another measurement. It continues to rotate vertically and horizontally until it has taken measurements in a 360-degree horizontal circle and usually a 310- degree vertical circle. All the measurements are accurate to around +/- 2mm. From these measurements we have an almost complete 3D survey of a cave. What makes this technology really exciting is the speed at which modern laser scanners work - up to 500,000 survey points per second! The resulting ‘cloud of points’ can be connected to adjoining scans to produce complete surveys of cave systems. Once downloaded into the processing software we can do lots of different things with the point cloud data - make simple sections and plans, elevation maps and isometric images, fly-through videos, explorable .mov images, TruView web delivery, and virtual or real models. Because of the accuracy of the survey data, it can also be used for monitoring the caves. We can go back and re-survey a cave after a year or a hundred years and see exactly how and where it has changed.

And the results are dramatic. The strange image at the head of this post is laser-scanned orthographic plan of the Peel Street caves, Nottingham’s largest cave system and a sand mine that was excavated between 1780 and 1820. Here’s an example, showing the caves in the Castle Rock, including the infamous “Mortimer’s Hole,”  Brewhouse Yard caves, and “Ye Olde Trip to Jerusalem Inn” caves (click for full-size image).

The images are stunning, and, on some of the high resolution versions available on the project website, you can begin to see the sedimentary structures:

 
So where did these accommodating sandstones come from? In the UK, they are part of the appropriately named Sherwood Sandstone Group, the outcrops around Nottingham being originally named the Bunter Sandstone; essentially all of them are red. They were deposited in desert and fluvial environments during the Triassic Period a couple of hundred million years ago, and their structures, including beautiful cross-bedding, record flash floods and blowing sand:

 
These photographs, courtesy of Ian West at the University of Southampton, come from the south coast of England where the Triassic Sherwood Group inevitably underpins the Jurassic Coast World Heritage Site. For the Sherwood Group, along with whatever its local equivalents may be in local nomenclature, extends across the UK and into the rest of Europe. The sandstones are often, as they are in Nottingham, poorly cemented and porous and can make excellent reservoirs for water and for oil and gas. But the Triassic sands don’t stop on the south coast of England – they can be found, in all their red glory, down the east coast of North America, where they preserve the first dinosaur footprints ever found (by the wonderfully named Pliny Moody working on his father’s farm in Massachusetts in 1802) and provide the building stone for New York’s iconic brownstones.  

These rocks formed as the supercontinent of Pangaea disintegrated, rifted apart to leave the testaments of red sandstone separated by the Atlantic Ocean:

Therein lies a story that links the mediaeval troglodytes of Nottingham with the Battle of Gettysburg – but that’s for another day.

 

[Thanks to Geoff Manaugh at his ever-fascinating BLDGBLOG for alerting me to the story of the Nottingham cave survey. Nottingham images from the caves survey project website.]