Travel Reference
In-Depth Information
had long observed in the Vancouver Island area could be recognized in
Tunisia as well.
The verdict
All the others had gone, leaving me alone in the empty hotel in El Kef. It
was very cold.
I had come to El Kef, Tunisia, in April of 1992 to help conduct the cru-
cial observations concerning sea level change and the "K/T" mass extinction
represented by the region's strata and fossils. The rocky country did not disap-
point. Tunisia has some of the best exposures of the Cretaceous/Tertiary
boundary known in the world, so it had been chosen as the site of a test to de-
termine whether the great mass extinction that ended the Age of Dinosaurs—
thought to have been caused by climate change, or sea level change, or even
by the collision of a great comet with the earth—was a sudden, short-term or
a slow, more gradual event. Two dozen scientists had come here to collect
sedimentary rock from either side of the Cretaceous/Tertiary boundary in
order to see whether the enclosed fossils disappeared right at the "K/T"
boundary or did so gradually well below the boundary and to see whether the
geological evidence suggested that the extinction coincided with a drop in
sea level, as so many had postulated. If the latter were true, then a sudden
dtop in sea level just might be one of the most extraordinary killers on the
planet.
We were especially interested in the nature of strata found in the last
meters of the Cretaceous. If sea level were dropping here, we would expect
to find evidence of shallowing water, and thus coarser-grained strata, as we
approached the "K/T" boundary and overlying Cenozoic strata. Our
methodology, our "time machine," was the same as that used on Sucia Island
in the account earlier in this chapter. We "walked" the section, making de-
tailed measurements of the stratal thickness and minute observations about
every aspect of the rocks: their grain size, their color, the types of fossils pre-
sent (or absent), the nature of sedimentary structures such as ripple marks or
