Geoscience Reference
In-Depth Information
seemed to be a layer of altered volcanic ash, but there didn't appear to
be any large crystals in it that might be used for dating through
radioactive methods. Nonetheless we collected some plastic bags
full of chunks, hoping that not all of the crystals had weathered to clay.
Luis also found a few fragments of fossil bone, but nothing worth col-
lecting. We would need to return some other time and try to get to the
site described in the scientific paper, but that would probably require
hiring either horses or a helicopter. At about noon, we headed back
to camp. As we drove, we passed drifts of hailstones that had washed
into nearby gullies. Although we had spent a miserable night exposed
to the elements, we clearly had not borne the brunt of the storm.
We returned to find that Frankie, Gerald, and the rest of the crew
had found three embryos in the eggs at the quarry. In addition, they
had measured and mapped another area of eggs on the flats. In the
first large grid, seventy-four clusters had been documented, whereas
the second, smaller grid contained about half that number.
Over the next three days, most of the paleontological team focused
on plastering and flipping the plaster jackets containing the abelisaur
skeleton. Meanwhile, Lowell's geological team began looking closely
at some of the exposures that contained eggs in the highest layer in
the sequence. Brushing off the loose dirt, we could see that the eggs
had been laid on a bumpy surface of the ancient floodplain. Assisted
by Julia and Frankie, Lowell used a tape measure and the leveling
bubble in his Brunton compass to map where the eggs sat on the sur-
face. The surface of the ancient floodplain was definitely bumpy, with
small mounds and depressions, just as David Loope had warned us to
expect with vertisols. However, it did not appear that the eggs sat in
these small depressions. We wondered why the depressions had not
been used as nests, but we could not be sure. The best news was that,
at last, the swarms of mosquitoes were now quickly dying off.
Most of our last five days in the field were devoted to moving the
blocks containing the abelisaur skeleton out of the quarry and down
to the nearest road, where they could be lifted onto a flatbed truck for
the trip back to Rodolfo's museum. The work went slowly, as some of
the blocks weighed over two thousand pounds. To flip these large rocks
and move them around the quarry, we used our four-wheel-drive
Passport that American Honda had given us to use during the expe-
dition. After all the blocks were flipped and ready to move, our
