Geology Reference
In-Depth Information
A second, younger class of meteorites, collectively dubbed achondrites, dates from
the time when the earliest materials of the Solar System were being reworked—melted,
smashed, and otherwise transformed. The diversity of achondritic meteorites is astonish-
ing—nuggets ofshiny metal, chunks ofblackened rock, some as fine-grained as glass, oth-
ers with lustrous crystals an inch across. Important discoveries of new varieties are still
being made in some of Earth's most remote regions.
The continent of Antarctica holds vast plains of ancient blue ice—places where it never
snows and the frozen surface may have remained unchanged for many thousands of years.
Rocks that have fallen from space just lie there, dark, out-of-place objects waiting to be
retrieved. International treaties banning commercial exploitation of the area, coupled with
limited access to the remote ice fields, ensure that these extraterrestrial resources will be
preserved for scientific study. Teams of warmly bundled scientists in helicopters and on
snowmobiles systematically scour mile after square mile of these forbidding ice deserts.
They carefully record and package each find, making sure that no hand, no breath contam-
inates its surface. Upon returning to civilization after each Antarctic summer season, these
meteorite hunters deliver their treasures to public collections, most notably the Smithsoni-
an Institution storage facilities in suburban Suitland, Maryland, where many thousands of
specimens are preserved in ultraclean, airtight storage cabinets within buildings the size of
football fields.
Equally rich in meteorites, though far less conducive to organized recovery and sterile
curation,areEarth'sgreatdesertsinAustralia,theAmericanSouthwest,theArabianPenin-
sula,andmostdramatically,NorthAfrica—thevastSaharaDesert.Wordhasspreadamong
Sahara-crossing nomads—Tuaregs, Berbers, Fezzanis—that meteorites can be valuable. A
singlepreciouslunarmeteoritefoundsomewhereintheshiftingsandsofNorthAfricaearly
in the twenty-first century is reputed to have fetched a million dollars in a private sale. It's
easy enough for a desert rider to get down off his camel and carry an odd stone to the next
village, where someone from an unofficial guild of meteorite middlemen, networked by
satellite phones and skilled in hyperbole, will offer him a pittance in cash. From one dealer
to the next, bags of rocks are passed, each time with a markup, until they reach Marrakech,
Rabat, or Cairo and thence travel to the buyers on eBay and the big international rock and
mineral shows.
More than once on geology trips to remote parts of Morocco, I've been offered burlap
bagsfilledwithtenortwentypoundsofrockspurportedtobemeteorites—“nomiddlemen,
fresh from the desert, just found last week.” These cash-only “deals” are often brokered in
dingy,windowlessbackroomsoftanmud-brickhouses,awayfromtheblazingdesertSun,
where it's almost impossible to see what's being offered. Once the formalities of greeting
and the traditional cups of mint tea have been shared, the seller dumps the contents on a
carpet. Some of the rocks are just rocks. Ballast. It's like a test to see if you know your
