the local conditions in the immediate aftermath of the
impact. One of those given the responsibility of studying
these fossils is Chris Lowery, a post-doctoral fellow in
palaeontology at the University of Texas at Austin.
“I’ve lain awake at night sometimes, wondering
what we’ve got in core 40,” he enthuses. “This is the
kind of thing I got into science to do. It’s so cool to
be part of something like this.” Lowery’s expertise
is in foraminifera, single-celled creatures that often
boast beautifully complex internal shells or ‘tests’. By
studying the chemical make-up of these fossilised
structures, he hopes to be able to reconstruct the
temperature, salinity and local productivity of the
water that filled the crater, giving an insight into the
kind of environment that survivors of the asteroid
would have faced.
Based on work elsewhere, we know that the asteroid
impact led to the extinction of more than 90 per cent of
all floating, plankton-like foraminifera. The species that
survived were typically small and generalist, but within a
mere 100,000 years they had diversified into dozens of
different species. “I’m very excited to see here at ground
zero what the properties of the ocean were that might
have driven that evolution,” says Lowery.
Meanwhile, analysis of the carbon isotopes in the
rock core will help us to understand how the carbon
cycle was affected by the impact. This in turn will tellABOVE: Artist’s
impression of
the Chicxulub
crater shortly
after impact. The
inner ‘peak ring’ is
where scientists
are focusing their
efforts today“I’ve lain awake at night
sometimes, wondering
what we’ve got in core 40”
300,000 YEARS
Because mammals from
several different groups
survived, mammal diversity
recovers quite quickly, soon
doubling the number of
species before the extinction.
1 MILLION YEARS
Deciduous trees, reliant on
wind pollination, begin to
return. Evergreens, which
rely on insects and animals
for reproduction, take
longer to bounce back.3 MILLION YEARS
In the oceans, there is a
rapid flourishing of the
plankton-like floating
foraminifera. This
contributes to the recovery
of most marine systems.10 MILLION YEARS
The surviving reptiles are quick to diversify,
with the appearance of iguanas, monitor
lizards and boas. Many insect lineages
survive the impact. After the event, ants
and termites increase in their diversity.
Butterflies, too, spread their wings.15 MILLION YEARS
In a few million years
the ancestors of most modern
birds undergo a rapid evolution
into the multitude of lineages
and thousands of species we
see today.