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A Visit to a Distant Impact Site

In South Texas we’re enjoying the twentieth consecutive day of one hundred plus degrees. On days like these I find my mind wandering back more than two decades to a time when I was happy to find refuge from the noon sun in a shaded spot that was itself over 115 degrees. Pulling up Google Earth Pro to retrace the route of that year 2000 expedition, I see places I knew decades ago as mere dust motes in the deep deserts of Saudi Arabia have now grown into veritable fly specs.

Living in Dhahran, Saudi Arabia in the 1970s I occasionally heard talk of meteorite craters five hundred kilometers south at a place called Wabar. The site was virtually inaccessible, far out in the desert called Rub’al Khali, sometimes shortened to just “the ‘Rub”. The name means “Empty Quarter” in Arabic. It actually does cover roughly one-quarter of the country’s area, making it the largest contiguous dune desert on earth. The portion in Saudi Arabia is equal to the combined land areas of California and Pennsylvania. Anyone wishing to find Wabar in those pre-GPS days had to plan a major expedition complete with Bedouin guides.

So I never thought seriously of driving to Wabar in spite of an interest in astronomy and meteorites (Twice I’d climbed to the bottom of Arizona’s Barringer Crater in the days when that was allowed). And after all, my job conducting flow tests on wildcat drilling rigs already took me into the Empty Quarter occasionally, although hundreds of kilometers east of the craters, and I found the place uncomfortable past belief; fine sand blew into hair, clothes, everything (I averaged one alarm clock per trip), yet the brackish rig water stank enough of sulfur to actually make people skip showering.

Mid-day shade temperatures in summer easily reached 126-130° F. On those days sand was spread across the rigs’ steel drilling floors because they became so hot that even heavy boots couldn’t protect the roughnecks’ feet. The workers survived their shifts by ingesting gallons of water and handfuls of salt tablets—no fancy electrolyte beverages back then.

Of course during the short winter the whole region became quite comfortable. Light jackets were even worn at night. Nothing for recreational campers to worry about then but sand cobras, scorpions, camel spiders, running off dune slip faces, and mechanical breakdowns. At least when we were on company business we didn’t have to drive there. We flew down in twin-engine Fokker 27s to within a few kilometers of the drilling location, landing on ancient lake beds.


Photo 1, F-27.

And, unlike the more desolate Wabar landscape, I found the eastern part of the Empty Quarter fascinating. Stark vistas mirror those vintage illustrations from the mid-1900s of how scientists thought Mars might look, with clear, cobalt skies and orange-colored dunes two hundred meters high.


Photo 2, Eastern Empty Quarter.

 


Photo 3, Eastern Empty Quarter.

The water table in the eastern Rub’al Khali is shallow enough that it actually lies at the surface in one place—scenic, but saltier than seawater.


Photo 4, Brine Lake.

 


Photo 5, Salt Crystals.

The entire Empty Quarter, from its east and then westward to Wabar, is dystopian in one sense, though; it wasn’t always as it is now. In the last Pleistocene ice age it was a thick savanna grassland with groves of trees and fresh water streams. People lived there then—even the Neanderthal if you go back far enough. Between present-day dunes one can walk the shores of long vanished lakes and occasionally find ancient arrowheads and crudely fashioned spear points.


Photo 6, Spear Point.

Ice age sea levels were 300′ lower. In place of our relatively shallow present-day Arabian Gulf was a lush, river valley paradise where the Tigris, Euphrates, and other rivers joined and flowed southward to the Arabian Sea.

In the 1990s the Middle Eastern camping world also made a big change. With GPS units it became possible to navigate to any point in the ‘Rub. And by then I had a full-sized Land Cruiser that I had tested out in Central Arabian canyon lands and the volcanos near the Red Sea. After reading the published reports on Wabar by Jeffrey C. Wynn and Eugene M. Shoemaker my camping friends were keen to put the craters on our year 2000 schedule.

Incidentally, Wabar isn’t the only big meteorite that ever struck the ‘Rub. In the 1990s Saudi Aramco made an extensive seismic survey across nearly the whole place looking for hydrocarbon-bearing structures. Sure enough, it revealed a few ancient sub-surface astroblemes. One was well over one hundred meters across and was buried only three hundred meters below the surface.

“Bring ’em back alive” is the first rule for expeditions into the Empty Quarter, and that requires meticulous planning. Our first decision was when to leave. We assumed temperatures would still be reasonable enough in March: a mistake!

I already knew from my visits to drilling rigs in the 1970s that summertime camping at Wabar was unthinkable. When the air temperature is above 120° F. in the shade, then on the unshaded desert our bodies’ cooling systems just can’t cope. Augmenting the high air temperature we have the sunlight roasting us from above plus ferocious infrared heating from the desert sand below. In the oil fields during summer the rule was never to hike away from your truck if it stalls, even if you’re running low on water. Those who broke this rule often died from heat stroke less than 200 meters from their vehicles.

We planned a nine-day trip: three to reach the craters, three exploring the site, two to return (by a more direct route), and a ninth in reserve. Our group would be four people in three Land Cruisers equipped with high and low-range 4-wheel drives. We planned for each car to carry four jerry cans of gasoline, four of water for each person in it, tools, car parts (full set of hoses, fuel & water pumps, etc.), a GPS unit, food, camp gear, and fiberglass skid boards. Individuals were penciled in to bring specific items such as the car-to-car radios, tow rope, maps, table, firewood, and scuba tank to refill aired-down tires.

All those jerry cans of gasoline would convert each Land Cruiser into a rolling fire-bomb. A basic decision for each driver was whether to transport his cans outside on a luggage rack or inside. If they leak and ignite outside, your chance of getting away from the car is much better than if they go off inside. But if they’re inside then you’ll be more likely to smell and find any small leak before it ignites. My decision was to get the sturdiest steel cans available, then pack them inside.

While I was living in Dhahran our company newspaper reported that an extended family actually did have such a fire while deep in the Empty Quarter. One of their three SUVs was carrying a gas can up on the luggage rack that leaked down to a hot tailpipe and blew up. As the gasoline and flames spread across the car exterior everyone got out except a three-year-old who was tangled in his seat belt. No one noticed except one boy—eleven or twelve years old, I think it wrote. He dived back in, freed his cousin, and dragged him to safety an instant before the fuel tank blew sky high. Helpless to extinguish the fire, though, the family watched while it consumed everything and eventually burned itself out.

We plotted a route south from Yabreen (end of pavement and last filling station) to Wabar that would be east of our return path through Ash Shalfa back to Yabreen. We expected the travel down and back would be as exciting as our time at Wabar, so why retrace a route and cut in half the number of discoveries?

Gasoline was a supply as well as a safety concern. I’d be driving a standard transmission without using air conditioning. Still, I knew from experience that I’d have at best 3.7 kilometers/liter when pushing through deep sand in 4-wheel drive with my sand tire pressures lowered to 12-14 psi. The other cars would be worse with their automatic transmissions. Leaving Yabreen my total gas inventory (tank plus jerry cans) would be enough to make the round trip down and back with only four gallons left—not enough margin. Somehow, we would need to find gas far out in the Empty Quarter.

There actually are a few refueling points in the deep desert, and they definitely look post-apocalyptic; one or two tanks are removed from scrapped transport trucks, set atop a dune, and equipped with turbine meters hooked up to rubber hoses. Usually, they’re partially buried to keep the sun from boiling away the gas or, worse yet, igniting it. A Bedouin shelters in a small tent alongside, trying to remember not to smoke. For a small fortune he will let gravity and the hose fill your tank. But those establishments are without gas and deserted for long and unpredictable stretches. We had GPS coordinates for two of them on our southerly route outbound to Wabar. The first was said to be very unreliable and the second less so. The only safe course if we found both of them shuttered would be to turn around and come home.

 

Day One

We started in early morning on the 370 kilometers south from Dhahran to pavement’s end at Yabreen. By mid-afternoon we were topping up our tanks at the tiny outpost and shopping for last minute items in its store.


Photo 7, Yabreen Store.

Disaster struck less than ten kilometers after leaving the road. I was the lead car and went through the first tricky stretch. The hard ground dropped down a meter into soft sand that immediately required a sharp cut to the right while reducing gear, then gassing it to climb back out. Seconds after I came through, the car following ten meters behind me flew out of control and ended up crashing hard into a dune.

The driver was our least experienced team member, and his Land Cruiser was less than a month old. It should be noted, though, that he later became a proficient desert driver and avid camper. He was uninjured, but the impact pulled his front left tire off its wheel and misaligned the front end. We decided to camp there and study our options. The first concern was how to remount—when you’re out past the back of beyond—a tubeless tire onto its wheel. We would not risk taking a car into the deep desert without four inflated tires plus a spare.

Near sunset we decided on a drastic measure. We removed the wheel and laid it on the sand with the tire placed in position around it. Then we sprayed starter fluid around inside the tire. Finally, holding a barbecue grill lighter in his fully extended arm one of us sparked the thing. The resulting explosion simultaneously inflated and remounted the tire. After patting out little residual flames on it we measured its pressure at 5 psi—enough to hold a seal while we inflated it to normal.

The car needed to be test driven; something seemed wrong with the front end. We were still close to Yabreen, so if it was mobile but unfit for the ‘Rub then one of us would accompany it back to there. It’s driver could then return alone to Dhahran safely on pavement. The remaining two cars would proceed to Wabar. It was already dark, so we deferred the test drive until morning and finish setting up camp.

I finished a quick supper, then arranged a foam pad, sheet, and pillow on top of the cargo inside my Land Cruiser. The others opted for sleeping in single occupant, pop-up tents with door flaps that zipped closed. To each his own. The main thing is never to sleep outside on that desert floor at night. I’ve slept outside in the Empty Quarter just one time, but that was in the eastern ‘Rub atop a five-hundred-foot dune; nothing bothers you up there.


Photo 8, Atop Dune.

The creatures of the Empty Quarter are nocturnal, and most will leave you alone. Sand cobras and vipers are looking for something small enough to swallow. Even the giant black scorpions are docile enough toward humans. But as dawn approaches, they’re trying to get under or into something, so don’t roll over. At any rate, unless you’re a very heavy sleeper the ubiquitous black beetles will wake you every few minutes as one explores inside your sleeping bag and clothing.

It’s mainly to avoid camel spiders, though, that I sleep only in my car or on its roof, depending on how hot the night is. The six-inch beasts (body plus legs) aren’t true spiders. They’re actually in the Solifugae Order of the Arachnida Class, along with the smaller vinegaroons of the American deserts. Spiders are a separate order of arachnid.


Photo 9, Camel Spider,

As ghastly as the dead ones are, it’s somehow the way the live ones move that gives humans the willies on an instinctive level. Such a macabre creature naturally inspires tall tales. Gulf War troops invented many of them, but one goes back at least to the 1970s. As the story goes: the camel spider silently slips up to a sleeping camel at night and injects a natural, local anesthetic into its leg. Then it proceeds to enjoy a midnight snack. The next morning the owner has a crippled camel. It supposedly also explains why the occasional Bedouin has a partly missing cheek or other major facial scar. One night he was careless about covering his face.

“Absolute rubbish,” declare all scientists who have ever studied Solifugae. They have no injection equipment nor any venom (or anesthetic!) to inject. Scientists do concede the beasts are carnivorous and have everything else they would need: silent and stealthy movements, good night vision, size (largest of all 1,100 Solifugae species), and those powerful pincers to cut up their prey—bugs, lizards, small rodents, and birds. They can slice through small bones with those, so could easily cut into camel skin.

Here’s my problem: scientists also tell us there are likely still many undocumented creatures in the Empty Quarter. How hard would it be for a species possessing all the other equipment to evolve an injector and anesthetic sack? Anyway, if someone wants to prove there really are only 1,100 species—not 1,101—by sleeping exposed some dark night on the Rub’al Khali sands, I’ll wish them the best of luck.

 

Day Two

After breakfast we determined that the damaged car was still roadworthy but had serious alignment issues. We sadly escorted our teammate back to Yabreen to begin his slow journey home. Then Steve, Jim, and I turned the remaining two Land Cruisers southward and set out.

We spent the rest of the day in easy, 2-wheel drive terrain. It was a chance to check how our vehicles took to the ‘Rub, as we steadily navigated southeast toward our first gasoline outpost. After 100 kilometers we reached the soft dune region and decided to make camp before dark. That’s prudent because even in daylight, set-ups are always inefficient. It was our second camp, but still maddening trying to remember where in our boxes and bags we stashed the dozens of items to start campfires, cook suppers, and prepare bed rolls. By the third night the process would be at least an hour quicker.

Each of us prepared his own supper. In the bush mine is probably the most basic, my fellow campers apply worse labels. That night I opened two cans—one tuna and one spinach—and set them in the campfire. Once they heated up, I slipped a glove on one hand, lifted them out of the fire, and ate from the can, putting the meat in lettuce or bread sandwiches. Afterwards the cans went into my garbage bag and the only clean-up was my fork and drinking glass. Lunches were simpler—a couple of pieces of fruit along with a can of sardines or sausages. Breakfast was the quickest: three slices of bread and a large glass of water followed by a cup of coffee. To relieve the monotony, I also brought some packaged pastries and cola.

 

Day Three

The next morning, we rose before the sun and prepared for dune field driving. We switched to 4-wheel drive and let most of the air out of our sand tires. These were designed for highway as well as sand driving. That meant they wouldn’t be as immune to becoming stuck as we would have liked. To give ourselves an extra edge we reduced their pressures to 12-14 psi. They still gripped the wheel rims tightly despite looking almost flat. Even with all that we could count on each vehicle becoming stuck about three times daily. Yet with shovels and skid boards it almost never took us more than ten minutes to free one and be off again.

We could have further reduced the frequency of stuck cars by simply driving faster, but that would be dangerous. Winds have a prevailing direction in the Empty Quarter. Those shape the windward sides of dunes into gradual slopes. Sand grains move up that incline until they reach the top and tumble down the leeward side, called the “slip face”. Slip faces are inclined at about 32 degrees. That doesn’t sound very steep, but it is. Driving carefully over the edge of a high dune’s slip face is terrifying the first time; it feels like rolling over a cliff. Sailing over the edge at high speed because you feared being stuck is far worse, though. Then it becomes what NASA calls an “NSE” (non-survivable event).

It’s basic physics. The dunes rest on and move across a flat, packed desert surface (hard pan). A fast moving car that zooms over the edge will probably not land on the soft slip face, since that falls away so steeply. Instead, the car’s momentum will carry it outward steadily as it accelerates downward until it finally strikes the hard pan. For a 70′ dune it’s as though the car was released by a crane to fall nose down 70′ onto concrete. Fly off a high slip face or pop the glove latch on your spacesuit—both NSEs.

But why not drive fast enough to avoid getting stuck, and then just slow down or veer away when you see an edge coming up? The problem is that often you can’t see the infernal things. Through most of the day the landscape was a glaring white-out. We wore the darkest polarized sunglasses available, but even then, the edges where windward sides ended were tricky to recognize against the similarly colored dunes behind them.

So, we drove just a bit slower, crossed windward sides of dunes a bit lower, and accepted more frequent stuck cars.


Photo 10, Stuck Car.

 


Photo 11, High-Centered.

On rare occasions one hung up high-centered, as in this picture from a later expedition to the eastern ‘Rub. Those were the worst and could take 40 minutes of digging to get free.

Operating with 4-wheel drive through the deep sand while constantly shifting the standard transmission down and up made the previous day seem like a luxury cruise. It required constant attention to decide where to approach each upcoming dune—to strike where its sand was hardest—and which gear would be best. Decide wrong and you’re digging out your stuck car yet again. Most of the time I stayed in high 4-wheel drive, but where the way ahead looked especially soft, I switched to the low range, selected my gear, and gunned the engine. Swerving back and forth through the worst patches with those aired-down tires felt more like swimming than driving. I tried not to think of my low gas mileage.

I needn’t have worried. Eighty kilometers from the last camp and before the sun was even very high, we reached the first deep desert refueling point—the least reliable one. And the place


Photo 12, Filling Station.

was manned and had gas! Only then did we know with certainty we would be visiting Wabar, and everyone’s spirits lifted.

We moved on after quickly topping up our tanks. The next stretch was especially difficult. It seemed like we spent more time digging out stuck cars than driving; by the time we crossed ninety kilometers of it the sun was setting. We were worn out but encouraged that we had put 170 kilometers of the worst driving behind us that day.

After supper I set an alarm for 1:00 am and retired early. When it woke me, I slipped out of my car and moved off a hundred meters with 10X50 binoculars and a lawn chair. On moonless nights Rub’al Khali night skies are among the darkest on earth. Light pollution is non-existent, humidity nearly zero, and the stars saturate the sky all the way down to the 360 degrees of unobstructed horizon. The latitude is south of that in the continental US, so in spring Sagittarius, Scorpius, and even Centaurus are high after midnight. Behind the first two our Milky Way galaxy glowed brightly and was well delineated. The binoculars resolved most of its small, brighter patches into open star clusters, each with dozens of member stars. Even a few stars in the Omega Centauri globular were visible. Sitting in a lawn chair under such a clear sky with total silence around me it was easy to grasp what the view actually was—that I was gazing out from our own curved spiral arm and across a gulf of 2,500 light years to the next arm inward toward the galactic core, itself 26,000 light years away. All those star clusters I was resolving in Scorpius and Sagittarius reside in that arm at distances from us of 2,000 to 3,500 light years.

 

 

Day Four

I wake up after sunrise in a dreamy haze after yesterday’s exertions and late-night star gazing. Jim and Steve have already stowed their tents and are finishing breakfast. I quickly eat mine, and we pull out.

The terrain becomes level desert with only tiny dunes, and we drift along easily. It’s so flat that any person, camel, or car would be clearly seen at a distance. It seems empty, though. But an hour into it we do spot something on the horizon ahead. The dreamlike quality increases when we come upon the lonely wreckage of a small plane.


Photo 13, Wrecked Airplane.

Around it a desert waste stretches empty to the horizon in every direction. Like Alice falling into the rabbit hole, it feels like we’ve dropped into the closing lines from Percy Shelley’s Ozymandias:

Nothing beside remains. Round the decay
Of that colossal wreck, boundless and bare
The lone and level sands stretch far away.

We press on. Behind us the hulk is left to ponder the glories of its high-altitude past and resume its “decay” back into the base elements from whence it came.

The farther we got from it the more things focused back into reality. Stretches of difficult driving helped. Occasionally a car became stuck but spending a few minutes digging it out was actually a welcome break from the driving.

Shortly before sundown we reached the second deep desert refueling point—the “more reliable” one. It lay next to a decades old operating base


Photo 14, Deserted Aramco Base.

of the Arabian American Oil Company, later renamed Saudi Aramco. The base had been deserted many years before, and the fuel facility had now joined it. If we had not found gas earlier at the “unreliable” facility, we would have been turning around here and returning to Dhahran.


Photo 15, Abandoned Trucks.

We examined derelict trucks and other artifacts left behind at the base. The only solid structure was a cinder block shed near the fallen down perimeter fence. Its door was missing, so even before entering we could see the universal radiation warning sign on an oddly shaped cylinder, standing half buried by sand accumulation.


Photo 16, Radioactive Container.

Steve and Jim reported from inside that the sand around it was unusually warm to the touch. I decided I could see and photograph it fine from outside the doorway. It likely contained one of the extremely radioactive sources used to check pipeline welds, and should never have been left abandoned and forgotten. We gave its coordinates to the company Security Department on returning to Dhahran.

We covered another twenty-four kilometers before camping. Our GPS units said only forty more to the craters. Since leaving the abandoned base we’d had a surface of moderately soft sand with only an occasional seif dune—fairly easy driving. It was sobering to think that we were probably in the exact type of terrain that the asteroid struck.

 

Day Five

We drove into Wabar from the east the next morning about 9:30, but I didn’t realize it at first. Somehow, I must have expected it to look drastically different from the forty kilometers of monotonous terrain that we’d crossed since breaking camp. As I drove slowly along watching my GPS, I actually thought, “Something’s wrong; it should be right here.” I finally woke up and noticed the many black objects scattered across the desert to my right.

Less than two hundred meters off—also to my right—was a nondescript dune that looked like dozens I had passed that morning. All at once I realized that it was the dune: the seif dune that’s burying Philby “A” Crater and is drawn on all the maps. I spent the next three days walking all around this celebrity and taking pictures from its crest. It must be about ten meters tall, yet its low profile is so underwhelming that I neglected to ever stand off and take its portrait.

We set up well to the south to avoid driving over any of the specimens. Our camp can be seen in Photo 17, a mosaic panorama taken from atop the famous dune, facing south.


Photo 17, Southern Horizon.

It covers about 100 degrees of horizon. The crescent-shaped pattern of lighter material on the far left is the western and part of the southern rim of Philby “B” Crater, seen mostly in shadow.

As the others began unpacking, I couldn’t resist a quick exploration of the site, breaking the rule about always setting up your camp first. Returning to the cars half an hour later, I was well on the way to heat exhaustion. While I sat on the ground in my car’s shade drinking electrolyte, we discussed the situation. It wasn’t even the hottest part of the day yet. If we were going to keep safe we would need to stay shaded and sedentary through the worst three to four hours of each day and do our sightseeing before and after.

Late in the afternoon we resumed exploring the site. We located the last vestige of the Philby “A” Crater


Photo 18, Philby -A- Crater.

casting a shadow at the south foot of the advancing dune. It’s now over twenty years later, so the crater is likely buried. The bush seen behind Jim’s right shoulder in the photo was growing in the 11-meter crater. It was recent. There’s no sign of the bush in the 1998 Scientific American picture of that crater. The dune can be seen approaching in a shot I took from the dune’s crest.


Photo 19, 11-Meter Crater.

Jim stood in the crater to recreate the Scientific American picture. The photos are taken a few years apart and the dune’s advance is apparent when the two are side by side. Comparing Philby’s 1932 map and my photo I estimate the thing had moved 120 meters southward in the 68 years. Incidentally, those wishing to examine Philby’s 1932 map can find it at the Meteorite Picture of the Day site for August 19, 2023.


Photo 20, Gassing Up.

Before supper that evening I emptied the last of my jerry cans into my fuel tank. No more driving a fire-bomb.

 

Day Six

After an early breakfast we continued inspecting the impact site. The events that created it are well described in the 1998 Scientific American article. Authors Wynn and Shoemaker explain how an iron-nickel meteor came in at a flat angle from the northwest, breaking into at least four pieces before impact. The two largest ones created the Philby “A” and Philby “B” craters. Their diameters are sixty-four and 116 meters, respectively. A smaller one made the 11-Meter Crater. The impact shock waves from the two largest ones flash melted tons of sand into black glass—called “impact melt”—and splattered it across the landscape. Farther out the shock waves welded individual sand grains together without melting to create a material called “impactite”, which looks somewhat like a pure white sandstone.


Photo 21, Impactite.

Happily, hundreds of fragments from the impactors survived and are also scattered among the pieces of white impactite and black impact melt. Wynn and Shoemaker explain that a reverse shock wave ripped through the impactors in the instant before they disintegrated, spalling pieces off their trailing surfaces and ejecting them toward the northwest. They go on to describe a blindingly bright fireball that would have risen to the stratosphere to create a glowing mushroom cloud.

The fierceness of the fireball’s radiant heat may explain why we found some occasional pieces of impact melt that were rough on one side and smooth on the other, with almost a mirror-like sheen.


Photo 22, Impact Melt.

One guess is that after the shock-melted globs fell onto the desert surface their upward facing sides reached even higher temperatures from radiant heating by the fireball above them.

In isolated places we found the ground littered with tiny ovoids and drop shapes of impact melt like those arranged in Photo 23.


Photo 23, Impact Melt.

It and Photo 24 were composed by positioning especially interesting impact melts near one another to be photographed. We didn’t see any naturally occurring concentrations as dense as that (We only wish!), not even after our second night when some original desert surface had been uncovered by a sandstorm. Photo 25 shows how the natural surface was before we messed with it, although that patch actually looks a little too depleted of interesting specimens.


Photo 25, Uncovered Surface.

We saw occasional pieces of impact melt that were shaped like barbells, as though rapidly spinning drops had solidified before they could spin in two. Others succeeded, but just barely. Then the resulting two drops would each be left with glass “tails”, some as thin as a human hair. A mystery is that since the impact is suspected to have happened at least as far back as the 19th century how could such delicate glass pieces survive 150 years of sandstorms. Perhaps they were buried under protective sand soon after the impact by those same storms.

Wynn and Shoemaker mention that following the impacts raindrops of molten glass apparently fell across the landscape for some time. They observed them wherever the original desert surface was visible.

But what was the source of this glass rain? Maybe countless tiny impact melt drops were first created by shock waves and then swept to high altitude by the fireball. Other drops perhaps condensed from white-hot microscopic droplets composing the fireball itself when it began to cool at high altitude. Whatever their origins, all of them must have solidified long before they reached the ground.

The range of shapes taken by both large and small pieces of impact melt seems endless.


Photo 24, Impact Melt.

Sometimes we try to guess how they might have formed. One seems to have flown through the air with a flat, molten tail trailing behind. Then that morphed into a unicorn’s spiral horn when perhaps something struck and spun the head. When a drop trailing two streamers was also set spinning the tails twisted into a braid. We saw many of the glass spheres called “Wabar pearls” that had mixed in with the sand. No two were the same. Some had smooth surfaces, but others were peppered by countless tiny drops that struck them and stuck. Some surfaces were black, while others were chocolate brown. A few rare ones had reflective, almost mirror-like exteriors. We also saw blue-colored impact melt. The color was especially apparent on fracture planes of pieces that had broken.


Photo 26, Blue Impact Melt.

Don’t be confused by Photo 26; what may appear to be inclusions projecting outward are actually smooth-walled chambers that once held gas bubbles.

We made a happy discovery as the morning gradually became a furnace. The sand under the Land Cruisers was quite cool after a day and night shielded from the sun. We ate an early lunch and then dug trench burrows under our cars to spent a pleasant four hours napping and reading. The air wafting in was still a bit warm. I measured 117 degrees with a mercury lab thermometer. It was a totally dry heat, though, and lying on the soft, cool sand we were much more comfortable than roasting in the tents. For two days it was fine, but if we had been at Wabar much longer than that the scorpions and spiders would have eventually found our paradise.

That evening after we’d finished supper and were relaxing around the campfire, we found out how quickly things can change. We would have had some warning if it had been daytime, or I had been off star gazing. When the stars begin disappearing across the sky, it’s hard to miss. We’ll always remember how rapidly the thing struck. In under thirty seconds a gentle evening breeze became a raging sandstorm with gusts that could knock us down. We rummaged around to find safety goggles to protect our eyes. Then, crouched over, we scurried about securing the camp as best we could. That night it took me awhile to fall asleep inside my Land Cruiser due to its constant rocking and the pinging of sand against it. I woke up several times during the night. Each time it was still rocking. I was sure it was losing its exterior paint.

 

 

Day Seven

The storm subsided a little after sunrise, and we crept out to survey its aftermath. The tents were partly buried, yet the sand under the car tires had been eroded. They were now in depressions. I wondered if they would have been eventually left resting on their axles had the storm continued for a few days. The paint jobs on the cars were fine. All I could guess was that the spherically shaped aeolian sands of the Empty Quarter are just not abrasive.   If it had been coarse, clastic river sand I’m sure all the paint would have been gone. A last note: the storm broke one of Steve’s tent poles. He’s a technical mountain climber, and the small tent was rated for mighty mountain winds. I’ll not mention the brand.

In the cool of the morning, I walked around the site drinking my morning coffee and made an interesting discovery. North of the bad boy dune that’s burying the craters—just beyond its windward side—an expanse of original surface had been exposed the previous night. It was littered with glass raindrops, many with impossibly delicate tails. I used some of these little specimens to arrange Photo 23.

Meteorites thrown off the impactor were not easy to find. The black impact melt is everywhere. In the bright sunlight the much rarer iron looks exactly like it. At one point I lightly kicked an obvious piece of impact melt to roll it out of the sand, and it clanked instead of clunking; sure enough, a good-sized meteorite. In addition to that one we eventually found a few more.


Photo 27, Meteorites.

The following year when I again visited Wabar (in December!) one of our group brought a metal detector.


Photo 28, Metal Detector.

It turned out to be surprisingly ineffective. The impact melt is composed of about ten percent of dispersed metal, so we were getting false positives everywhere. When someone becomes totally aggravated, the Chinese call it “spitting blood”.

As with all iron-nickel meteorites, those from Wabar can be polished and acid-etched to reveal Widmanstatten patterns.


Photo 29, Wabar Etch Pattern.

The spectacular pictured specimen in the photo is in the private collection of Scott McGregor. Only iron meteorites ever exhibit these striking crystal structures. They form in the cores of small planetoids as they cool and solidify over periods of hundreds of millions of years. If one of these is later shattered in a collision with another planetoid, it produces iron-nickel asteroids.

The most singular object I found at Wabar was a nearly homogeneous mix of impact melt, impactite, and meteoritic material.


Photo 30, Mix of Everything.

It was almost as light as foam, and would have easily floated in water. No one examining it would ever doubt the violence and turbulence of the Wabar cataclysm.

As our last full day at Wabar drew to a close, we found ourselves wandering about the site taking last looks, unwilling to start supper until dark.


Photo 31, Last Look Around.

None of us knew if he would ever get to return. With me it was a nagging unease that I had maybe missed something major and left it unseen. I wonder if each of our lunar astronauts had similar feelings before leaving the moon. Maybe not, they had specific mission tasks to perform and knew they had accomplished them.

 

Day Eight

We break camp and leave shortly after sunrise. As it was with my second day on the drive down, the return trip from our expedition into the ‘Rub gave me an anticlimactic, dreamlike feeling. In the afternoon we float into the outpost of Ash Shalfa, the third “maybe” gasoline source. Happily, they have it. This means that even though we still had enough to make it to pavement and dependable stations, we can forget frugality and run air conditioners.

We gas up and discover that a well here produces clear, slightly brackish water. A standpipe feeds into a trough that’s big enough to water a hundred camels. After our week living in sand, we can’t resist it.


Photo 32, Camel Trough.

Then, already dressed and ready to drive out, we see something appear on the horizon.   As though stepping out of a mirage a speck slowly resolves into two approaching camels: a tiny calf with its mother. Her objective is the watering trough, of course.

Camel faces aren’t expressive, yet at the trough the cow’s body language somehow communicates her fierce protectiveness along with motherly pride. She constantly hovers over the calf, and confronts me when I move in for a picture.


Photo 33, Camel & Calf.

We take care not to disturb him after that. I’m reminded of how gigantic camels are compared to horses. Mount one and when he stands up the altitude practically gives you a nosebleed. I’ve ridden both, though, and would prefer the camel any day: far more sure-footed.

The little one can’t be more than a few days old, with all that curly calf fur. He even still has a dried-up umbilical cord attached to his undercarriage. He eyes us curiously. We’re probably the first large creatures he’s seen apart from his mother.   We guess that the other camels standing about the location are the cow’s herd, and she’s rejoining them after staying behind to deliver. From the direction she came we’re sure the tyke’s been feeding and hydrating only on mother’s milk since birth. So it is that we witness his first tentative experience with the magical liquid we call “water”.


Photo 34, Camel Calf.

After leaving Ash Shalfa, there was no more relaxed driving. Another 34 kilometers of dunes, then we hit the flats and pushed pedal to metal, heading home. When we stopped and made our last camp that evening there was just eighty kilometers of flat, easy driving between us and the pavement at Yabreen.

 

Day Nine

Our final day was a long one, but I have little recollection of it. After breaking camp, we quickly covered the eighty kilometers to pavement and then just kept driving. It was going to be a tiring day, but no one suggested camping somewhere for an extra night. We looked forward to seeing our families too much. I do remember drinking a couple of colas at stops along the highway—not because I like them that much, but in order to stay awake. Monotonous highway driving can be sleep-inducing after so much time spent off-road. Anyway, we reached Dhahran a little before midnight without incident.

 

 

Acknowledgments
The author wishes to express his gratitude to Anne Black and Scott McGregor for their assistance. Anne initially conceived and encouraged the writing of the article. Scott applied his computer skills to dramatically liven all the photographs; then, as a much appreciated bonus, he performed a careful line-by-line edit of the initial draft.

 

Alan Keese
August 2023

 

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