Rub' al-Khali Expedition 2008
Text: Svend Buhl, Photos: Svend Buhl and Thomas Kurtz
Coincidences and other improbabilities
Later, I was just about to calculate our drinking water reserve,
Thomas called me over to the vehicle. He had discovered a praying
mantis on one of the rear wheels. It was an Arabian Devils Flower,
Blepharopsis mendica. A male as could be seen by the feathery split
antennae. We were still wondering why the insect of all things had chosen
to land on the tire when I discovered a second mantis on one
of the front tires. This time it was an adult female specimen measuring
seven or eight centimeters, also of the Blepharopsis species.
Arabian devil's flower, Blepharopsis mendica (Fabricius 1775). The adult female measures approximately 7.5cm
When gently blown at, the beautiful animal will slowly rock from side
to side. This is typical behavior of most cryptic species. This swaying is
mimicking a dried leaf or branch moving in the wind.
We stood and watched the confiding animals quite some time in the hope to observe
the catch of a locust or moth but both insects were simply occupied with personal hygiene. Particularly
the barbed triple folded forelegs received a thorough cleaning from dust and plant fibers.
In the morning both animals were still there. Before we stowed away our gear we took the
insects from the tires which they put up with unopposed, although the species can fly for
short distances. When brought together on the ground they showed no aggressiveness
among each other. Although Blepharopsis mendica is commonly known for cannibalism I presume
this is rather the case in captivity and when in lack of food.
In the present habitat and with a decent population of prey there would be no cause for this.
The female is rather interested in our camera than in the male specimen which is visible in the background
The morning was hot and remarkably clear. But already a short time after sunrise
the scenery had changed. Where had been a distinct horizon only minutes ago now only
multiple looming bewildered the eye. We had just climbed in the Land Cruiser and were
about to start when we became witnesses of a rare form of the Fata Morgana. Low above
the horizon, apparently in a distance of barely four kilometers, a flat building
emerged from the flickering heat that quickly gained focus and plasticity. Beside
it and out of nothing an elongated bronze colored object materialized that seemed
to crawl alongside the building. By binoculars we could see that this was a large
semi trailer. The illusion presented itself in such a way that the building as well
as the truck could both be seen twice. The first reflection showed the scene according
to the common rules of gravity upright while the second mirroring produced the objects
With the field glass we were able to make out single persons wrapped
in white dischdaschas that went inside and out of the building. We consulted
our maps and GPS and found out that the nearest asphalt road suitable for larger
trucks let alone buildings was at least eighty miles from our position as the crow flies.
‚Perhaps an image from the future?' Thomas suggested eerily. 'You watching too much TV pal'
I replied raising a brow. 'Don't watch no TV at all' it came back neutrally from behind the
binoculars while he stared at where the mirage loomed in the distant haze. 'Then maybe that is the problem'
I settled the matter after a pause which I needed to figure whether we both might have had too much of sun.
After ten minutes the construct dissolved, but not before the semi trailer evaporated
a black plume of smoke and slowly rolled away. Like a steamer on a calm sea, half a degree
above the horizon, the vehicle silently floated into the monochrome lead grey of the desert
sky. Much too late, when the image was already about to disappear, I snapped the camera and shot a photo.
We had been spellbound watching the spectacle without even thinking of documenting it. Fine explorers we were.
The only find we made that day was a very small and beyond recognition
weathered fragment that was almost completely embedded in the soil. It was
impossible to see from the car. Fortunately Thomas had stepped on it when we stopped
to empty ourselves after we had searched the complete noon without success. It was the
only halt we made until dusk. And exactly
at this spot, right below where he stepped off the car, Thomas had found the meteorite
that hardly weighed twenty grams.
This find triggered a stimulated discussion on coincidence versus determinism that
continued for the best part of the afternoon. While I argued that the probability
of us finding a miniature meteorite where quite high, pretty much regardless where
we would step out of the car, my team mate defended the powers of destiny which
he believed had led us to stop at the very spot of the find. My appeals to my companion's
self-concept of rational thought were to no avail. He repeatedly claimed
that now 'it was proven', that he was chosen as an 'instrument of divine providence'.
We had a lot of fun that day.
The afternoon went by without further incidents, presumably the divine
providence had lost its interest in the 'chosen one' as we made no further finds.
We camped between the tracks of our search loops next to a narrow milk weed bush (Calotropis procera)
which we had used as a landmark for our bearing
the last few hours. Even after dusk we continued prospecting on foot for another hour until we sat
down at the campfire.
The next morning we got up long before sunrise. When the first rays of the new
sun immersed the eastern sky in a fiery glow we had already completed a brief breakfast and
stowed away our belongings in the car. I intended to start early today, to
compensate for yesterdays meager finds.
Found by accident, 'Rub' al-Khali 012', a 68.5g ordinary chondrite
But I had not reckoned on Thomas, who sat on the co driver's seat
and was still occupied entrusting his journal entries in epic dimensions.
This could take a little longer as I knew from experience and so I grabbed my toothbrush to
promenade the gravel bed within range of sight of the vehicle. Automatically I focused the
What could there be more contemplative than strolling the gravel beds of the Rub'
al-Khali in the early morning light, tooth brushing and studying the manifold forms of desert
weathering on the surface? I didn't make it far though, because only a few paces from the car
a stone attracted my attention. In the shadows this particular pebble seemed just a fraction
darker than the others. 'You wanted to take care of this one already yesterday evening' I remembered.
For some mysterious reason my footprints had wandered off just three meters ahead of it, I noticed bemused.
As I stood directly above the minute rock I still didn't know what to make
of it. A scallop shaped fracture irritated me. This type of fracture is
common rather for cryptocrystalline minerals like flint stone or chert while meteorites
tend to break rather irregular due to a coarser grain size. Otherwise everything made
sense: color, texture and shape pointed to a meteorite. I continued brushing my teeth.
Still far from being wide awake in this early morning hour and still without a
coffee the situation slightly overstrained my. 'Maybe I should get to the car and
get the magnet' I thought. While I searched for the device Thomas obviously was
still busy composing what seemed to be a significant literary opus comparable
in dimension to the Encyclopedia Britannica at least. He was so submerged in
his creative outpour, not even my admittedly diffuse declaration, 'believe I
got something', was able to disturb him.
The stone attracted the magnet with considerable force. As
I could see on closer inspection the edges of the fracture had been smoothened
by sand abrasion. What I had taken for a scallop shaped flaking was in fact a true
weathering fracture on the surface of a genuine meteorite. A deep contraction crack and a flank
that showed remnants of flow lines clearly confirmed the meteoritic nature of the walnut sized rock.
Finder Thomas Kurtz (left) and author together with 'Rub' al-Khali 017'
'Scored' I called out in the direction of the car, whereupon Thomas darted
up in his seat like a greased lightning thereby catapulting his ball pen out
of the window. With three huge paces he hurried over to where I was lying on the
ground, inspecting the meteorite. 'Impossible' he protested. ‚I walked along here
three times yesterday'. 'Sure' I needled him, 'but you wouldn't even find the
Hoba mass if it lay here'. We both could get a laugh out of it for in fact as
our footprints showed to us, 'the chosen one' and I had walked past the meteorite quite
close at least two times without noticing it on the previous day. Today had started
out great, things could go on like this.
Sand abrasion and desert pavement
In fact it went on like this. Distributed throughout the day we found five more
masses, which we assigned to two different fall events. While brushing my teeth
I had in fact discovered a new strewn field. Remarkably we had combed the same
area the previous day and hadn't found a single mass. The terrain was ideal.
Absolutely void of any cover, no grain sizes above 50mm and the borderless plains
were big enough to land a A-380 Airbus on them without even kicking the trust
reversion. We drove dead straight parallel search tracks three to five kilometers
in length and with intervals of fifty meters. In the late afternoon when checking
our GPS we discovered a gap in our search pattern located at the northern end of
the strewn field we were working on.
We would have good light for at least one more hour. So we decided to go there and turned.
Because the course into that particular search area would lead us
driving directly against the sun prospecting from the car along the
way was not an option. I kicked down pedal to metal which was a novelty
on that trip. Against the deep standing sun there was not much to bee
seen of what was ahead of us. But because we hadn't seen any potential
obstacle on the dead flat plain during the last
two days of driving the risk of colliding with anything more hazardous
than camel droppings was negligible.
'Rub' al-Khali 018', in situ photo in back light
Generally the driving on the even terrain through the desert had a somnambulistic
touch to it. Wile searching for meteorites from the car and provided that the visibility
is good and the vehicle is kept at jogging speed, a glance ahead every ten minutes or so is
completely sufficient, to guide the vehicle safely. Occasionally it may happen that the driver
is so lost in his task of scanning the surface at his side for meteorites that he completely
forgets to look ahead at all. In this case a too easy going attitude to driving may admittedly
lead to sudden and unexpected perspectives.
Meanwhile we were driving for five or six minutes with accelerated speed when I spotted a larger
object on the plain ahead of us. Against the blinding sun one could not determine if bright or dark
let alone what it was. Therefore I adjusted our course a little towards the spot and decelerated to
catch a quick glimpse while I would pass the object close at the driver's side. I didn't pay much
attention because whatever it was it seemed too obvious on the plain and too big to be a meteorite.
In the light of the sinking sun there wasn't much to be seen anyhow. But in the moment of passing
for a second an image of the rock flashed in my mirror that triggered me to slam on the brakes instantly.
Adherent patches of caliche preserved on the lee side of the meteorite mark the level of a previous sedimentation
In my enthusiasm I had forgotten that, as always, we were driving with
our windows down. This minor but decisive fact brought about that the humungous
dust cloud which trailed us like a pyroclastic flow, now also distributed
itself unhindered in the interior of our car. Coughing and exclaiming fierce
maledictions we rescued ourselves into the open.
It must have triggered a quick reaction because the questioned rock rested in a
distance of not even forty meters from where the Land Cruiser had come to a halt.
Now, with the sun from the back and already from this distance it was obvious that
we were dealing with the genuine thing. On approaching the new find we mutually
congratulated us. Instead of walking straight to the meteorite we circled
the mass in a distance like Tibetan pilgrims a holy mountain, because the
sight of the large
mass in the light of the evening sun on the bright gravel pavement was simply
to awe inspiring.
Studio image of 'Rub' al-Khali 018'. Note the distinct abrasion through wind borne sand ('corrasion') in the upper third of the meteorite
On closer inspection we figured that the meteorite showed strong signs
of abrasion towards a single side, more precisely towards 55° North by
Northeast. On the flank pointing into this direction sand abrasion had
erased several centimeters of the original material. Over the millennia
the wind that on increasing speed carries grains of sand and silt works
like a steady sandblaster on the meteorite. This way it had molded
deep tunnels and cavities into the meteoritic stone. Even in the
surfacing side of the rock deep channels and hollows had formed,
originating from the North by Northeast pointing side. This process
was only visible on the windward side but not on the lee side, that still
showed remnants of heavily weathered fusion rind.
The distinct one sided abrasion indicated that the meteorite during
his terrestrial lifetime had never been moved in his relative position.
It was also a proof for the steadiness of the trade wind for at least the last
fifteen to twenty thousand years. Most probably the meteorite had been covered
by the accumulated sediments before and was uncovered successively by the
increasing wind erosion. Thus after climate
changes have led to a disappearance of the natural plant cover that prevented
the top soil from eolian deflation. This was obvious from the fact, that the grade of destruction was much heavier
in the upper third of the meteorite while the lower portions which
currently suffered most of the sandblast, showed a much lesser abrasion ratio.
Top view with indication of the prominent wind abrasion originating from 55° North by Northeast
Although it is true that silt and finer grained
dust particles commonly move up to heights of one to two meters
above the surface their destructive capacity when impacting on meteorites
and other rocks is negligible due to their low mass and small grain size.
The abrasion that was visible on our meteorite rather resulted from sand grains
with a grain size of 0.1 to 1mm. These sand grains are transported by the wind
rolling and bouncing and arely reach heights above two centimeters. In this range close above the surface
the mechanical abrasion through sand is most harmful.
Because our recent find displayed the strongest abrasion in the upper third,
five to seven centimeters above the resting surface, this pointed towards a
considerable period of time which the mass must have spent embedded in the ground up to the
lower level of the mentioned destruction zone. During this period the main body
of the mass must have been protected from the sand abrasion.
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