"Venezuelan Tapuis: Their Caves and Biota." Edited by Roman Aubrecht
and Ján Schlögl. Comenius University, Bratislava; 2012. ISBN
978-80-223-3349-8. 8 by 11 inches, 167 pages. Free PDF file at http://www.academia.edu/3462814/Venezuelan_tepui_-_their_caves_and_biota
.
The tapuis of Venezuela are isolated mesas of Precambrian quartzite
and sandstone with spectacular scenery, including 807-meter Angel
Falls, the world's highest waterfall. They also contains some large
and unusual karst features, including huge shafts such as Sima Major
on Sarisariñama Tepui, 300 meters wide and deep, and the Ojos de
Cristal Cave System, 16 kilometers long. The helicopters sitting on
the floor of the 200-meter-high entrance to Cueva El Fantasma in
figure 13 look like flies. Quartzite is not very soluble, so the caves
have been assumed to be very old, but no speleothems have been dated
to before the Pleistocene. Ten feet of rain a year no doubt has
something to do with their formation.
Fifteen authors have contributed to this book. It is very much a
scientific monograph, but even the most technical sections have many
color photographs of unusual surface and underground features.
Following a brief introduction to the geology and climate of the area,
there is a hundred-page geology chapter. The part of that of most
general interest is a survey of many of the caves known on the tapuis,
although the only maps are small-scale outline maps. Other sections
cover water chemistry and curious speleothems of unusual composition,
such as silica. Geomicrobiology is apparently involved in the creation
of some of the formations. The final chapter, on biota, is about
thirty-eight pages long and covers only land snails, aquatic insects
both surface and cave, and herps. The bibliography is fourteen pages
of fine print.
To download the PDF file (30 MB with compressed illustrations), you'll
need to sign up for something called academia.edu. It is free. I don't
know yet how much of a nuisance belonging to it will be; presumably
there's some more or, probably, less obvious way to cancel your
registration. If you are the sort of person who belongs to Facebook
downloading may be easier. The color photographs are a very important
part of the book, but it will be expensive to print out if you want to
make a color hardcopy. If you do print it, note that the PDF file does
not contain the blank back of the cover, so the left-hand pages all
appear on the right. Before making a two-sided printout, add the blank
page or delete the cover page.—Bill Mixon
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