2013-03-27. New Evidence Ancient Asteroid Caused Global Firestorm On Earth. Excerpt: A new look at conditions after a Manhattan-sized asteroid slammed into a region of Mexico in the dinosaur days indicates the event could have triggered a global firestorm that would have burned every twig, bush and tree on Earth and led to the extinction of 80 percent of all Earth's species, says a new University of Colorado Boulder study. ...the collision would have vaporized huge amounts of rock that were then blown high above Earth's atmosphere. The re-entering ejected material would have heated the upper atmosphere enough to glow red for several hours at roughly 2,700 degrees Fahrenheit -- about the temperature of an oven broiler element -- killing every living thing not sheltered underground or underwater. ...there was enough infrared radiation from the upper atmosphere that reached Earth's surface to create searing conditions that likely ignited tinder, including dead leaves and pine needles. If a person was on Earth back then, it would have been like sitting in a broiler oven for two or three hours.... ...The asteroid-Earth collision is thought to have generated about 100 million megatons of energy.... http://www.sciencedaily.com/releases/2013/03/130327144249.htm. Science News.
2013-02-07. New evidence comet or asteroid impact was last straw for dinosaurs | Robert Sanders, UC Berkeley News Center. Excerpt: The demise of the dinosaurs is the world’s ultimate whodunit. Was it a comet or asteroid impact? Volcanic eruptions? Climate change? ...In an attempt to resolve the issue, scientists at the Berkeley Geochronology Center (BGC), the University of California, Berkeley, and universities in the Netherlands and the United Kingdom have now determined the most precise dates yet for the dinosaur extinction 66 million years ago and for the well-known impact that occurred around the same time. The dates are so close, the researchers say, that they now believe the comet or asteroid, if not wholly responsible for the global extinction, at least dealt the dinosaurs their death blow. “The impact was clearly the final straw that pushed Earth past the tipping point,” said Paul Renne, BGC director and UC Berkeley professor in residence of earth and planetary science. “We have shown that these events are synchronous to within a gnat’s eyebrow, and therefore the impact clearly played a major role in extinctions, but it probably wasn’t just the impact.” The revised dates clear up lingering confusion over whether the impact actually occurred before or after the extinction, which was characterized by the almost overnight disappearance from the fossil record of land-based dinosaurs and many ocean creatures. The new date for the impact – 66,038,000 years ago – is the same within error limits as the date of the extinction, said Renne, making the events simultaneous. He and his colleagues will report their findings in the Feb. 8 issue of the journal Science…. Read the full article: http://newscenter.berkeley.edu/2013/02/07/new-evidence-comet-or-asteroid-impact-was-last-straw-for-dinosaurs/
2012 May 27. It Took Earth Ten Million Years to Recover from Greatest Mass Extinction
| ScienceDaily. Excerpt: Life was nearly wiped out 250 million years
ago, with only 10 per cent of plants and animals surviving…recovery from
the crisis lasted some 10 million years…There were apparently two
reasons for the delay, the sheer intensity of the crisis, and continuing
grim conditions on Earth after the first wave of extinction.The
end-Permian crisis, by far the most dramatic biological crisis to affect
life on Earth, was triggered by a number of physical environmental
shocks -- global warming, acid rain, ocean acidification and ocean
anoxia. These were enough to kill off 90 per cent of living things on
land and in the sea…Current research shows that the grim conditions
continued in bursts for some five to six million years after the initial
crisis, with repeated carbon and oxygen crises, warming and other ill
effects.Some groups of animals on the sea and land did recover quickly
and began to rebuild their ecosystems, but they suffered further
setbacks. Life had not really recovered in these early phases because
permanent ecosystems were not established….
2012-06-25. ‘Nature’s Masons’ Do Double Duty as Storytellers. By Sean B. Carroll, New York Times. An article relevant to GSS Climate
Change chapter 8, Life and Climate chapter 9, and A Changing Cosmos
chapter 1. Excerpt: GUBBIO, Italy — …Limestone is composed largely of
crystallized calcium carbonate. Some of it comes from the skeletal
remains of well-known creatures like corals, but much of the rest comes
from less appreciated but truly remarkable organisms called
foraminifera, or forams for short. Forams have been called “nature’s
masons,” … these single-celled protists construct surprisingly complex,
ornate and beautiful shells to protect their bodies. After forams die,
their shells settle in ocean sediments…. While tiny relative to
ourselves …, forams are extremely large for single-celled organisms, …
largest forams can reach a few centimeters. … forams are particularly
valuable to geologists and paleontologists in telling us about Earth’s
history. The forams in the limestone just outside Gubbio provided the
first clues to … an asteroid that struck earth at the end of the
Cretaceous period, 65 million years ago…about the size of Mount Everest
and traveling at about 50,000 miles an hour when it hit the earth,
drilling a 120-mile-wide crater and ejecting so much material into (and
even out of) the atmosphere that food chains on land and in the oceans
were disrupted for thousands of years. The impact caused one of the
greatest mass extinctions in history, from the largest animals to tiny
forams. Read the full article: http://www.nytimes.com/2012/06/26/science/natures-masons-do-double-duty-as-earths-storytellers.html?_r=1&emc=eta1
2012-04-05. Bus-Size Dinosaurs, Fuzzy as Chicks | by John Noble Wilford, The New York Times. An article relevant to GSS Life and Climate chapter 9. Excerpt: Fossils discovered in northeastern China of a giant, previously unrecognized dinosaur show that it is the largest known feathered animal, living or extinct, scientists report. …The adult was at least 30 feet long and weighed a ton and a half, …. The two juveniles were a mere half ton each. The new species was a distant relative of Tyrannosaurus rex …. Xing Xu of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, who was the lead author of the paper, said …that it was “possible that feathers were much more widespread, at least among meat-eating dinosaurs, than most scientists would have guessed even a few years ago.” Dr. Xu said the feathers were simple filaments, more like the fuzzy down of a modern baby chick than the stiff plumes of an adult bird. Such insubstantial feathers, not to mention the animal’s huge size, would have made flight impossible. The feathers’ most important function was probably as insulation. The species has been named Yutyrannus huali, which means “beautiful feathered tyrant” in a combination of Latin and Mandarin. Mark A. Norell, a curator of paleontology at the American Museum of Natural History in Manhattan, who had no part in the research, said the findings were significant because they swept aside a longstanding argument that perhaps dinosaurs had feathers only when they were small and shed them as they grew…. Read the full article: http://www.nytimes.com/2012/04/05/science/dinosaur-dig-in-china-turns-up-largest-known-feathered-animal.html?_r=1&nl=todaysheadlines&emc=edit_th_20120405
2012 Feb 3. Global Extinction: Gradual Doom as Bad as Abrupt. NSF Press Release 12-019. Excerpt: The deadliest mass extinction of all took a long time to kill 90 percent of Earth's marine life--and it killed in stages--according to a newly published report. It shows that mass extinctions need not be sudden events. Thomas Algeo, a geologist at the University of Cincinnati, and 13 colleagues have produced a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic.
2010 May 17. Ancient
mass extinction of fish may have paved way for modern species. By
Amina Khan, LA Times. Excerpt: ..."It's
clearly one of the most important papers published in recent years" in
paleontology, said John Long, a paleontologist at the Natural History
Museum of Los Angeles County who was not involved in the study.
"Forty-four percent of all vertebrate life went extinct at that point,
and that was not recognized before."
...That event was
one of the most devastating in Earth's history, on a par with the one
that killed off the dinosaurs 65 million years ago, said Lauren Sallan, a
paleontologist at the University of Chicago and lead author of the
...And just as
the fall of the dinosaurs made room for mammals to rise, she said, this
extinction made way for modern marine life such as sharks and the
ancestors of modern fish — as well as for tetrapods, ancestors of
terrestrial vertebrate life.
2010 March 23. Dinosaurs' dominance 'helped by mass volcanism'. By
Paul Rincon, BBC News. Excerpt: Immense
volcanic activity helped the dinosaurs rise to prominence some 200
million years ago, a study suggests.
Dinosaurs were the dominant vertebrates on
land for some 135 million years.
While it is widely accepted that an asteroid
or comet wiped them out, there has been less agreement on the factors
which led to their ascendancy.
Research in PNAS journal suggests volcanic
eruptions changed the climate, causing a mass extinction that wiped out
the dinosaurs' main competitors.
The scientific paper...looked at several
lines of evidence such as the remains of plant wax and wood from
sedimentary rocks interbedded with lava flows. From these, they were
able to extract vital data about the climate at this time.
The lava flows are dated to the end-Triassic
extinction, 201.4 million years ago, which wiped out 50% of tetrapods
(four-limbed animals) on land, 50% of terrestrial plants and 20% of
2010 March 9. Alvarez Theory on Dinosaur Die-Out Upheld: Experts Find
Asteroid Guilty of Killing the Dinosaurs. By Lynn Yarris, Lawrence
Berkeley National Laboratory. Excerpt: In the
March 5, 2010 edition of the journal Science, an international panel of
41 experts in geology, paleontology and other related fields, after an
exhaustive review of the data, declared an end to a 30 year controversy
over what triggered the extinction of the dinosaurs – an asteroid or
volcanoes. The panel ruled in favor of the asteroid, a theory first put
forth in 1980 by one of Berkeley Lab’s greatest scientists, the late
Nobel laureate Luis Alvarez, and his son Walter, a geologist with UC
2009 April 28. New
Blow Against Dinosaur-killing Asteroid
Theory, Geologists Find. ScienceDaily.
The enduringly popular theory that
the Chicxulub crater holds the clue
to the demise of the dinosaurs, along
with some 65 percent of all species
65 million years ago, is challenged
in a paper to be published in the
Journal of the Geological Society
on April 27, 2009.
The crater, discovered in 1978 in northern
Yucutan and measuring about 180 kilometers
(112 miles) in diameter, records a
massive extra-terrestrial impact.
When spherules from the impact were
found just below the Cretaceous-Tertiary
(K-T) boundary, it was quickly identified
as the "smoking gun" responsible
for the mass extinction event that
took place 65 million years ago.
It was this event which saw the demise
of dinosaurs, along with countless
other plant and animal species.
However, a number of scientists have
since disagreed with this interpretation.
The newest research, led by Gerta Keller
of Princeton University in New Jersey,
and Thierry Adatte of the University
of Lausanne, Switzerland, uses evidence
from Mexico to suggest that the Chicxulub
impact predates the K-T boundary by
as much as 300,000 years.
...From El Penon and other localities
in Mexico, says Keller, "we know
that between four and nine meters of
sediments were deposited at about two
to three centimeters per thousand years
after the impact. The mass extinction
level can be seen in the sediments
above this interval."
...The scientists also found evidence
that the Chicxulub impact didn't have
the dramatic impact on species diversity
that has been suggested.
..."We found that not a single species
went extinct as a result of the Chicxulub
impact," says Keller.
...Keller suggests that the massive
volcanic eruptions at the Deccan Traps
in India may be responsible for the
extinction, releasing huge amounts
of dust and gases that could have blocked
out sunlight and brought about a significant
2008 December 15. Fight
over dinosaur death flares anew
in S.F. By David
Perlman, San Francisco Chronicle. Excerpt:
SAN FRANCISCO -- The age of the
dinosaurs ended abruptly about
65 million years ago when some
catastrophic event drove them to
extinction, and now a vehement
controversy over their disappearance
is emerging anew.
...An international group of scientists
is arguing that poisonous fumes from
violent waves of volcanic eruptions
in India millions of years ago killed
off the beasts, not - as UC Berkeley
scientists first proposed nearly 30
years ago - the impact of a giant meteorite
that blasted a huge undersea crater
in Mexico and touched off a kind of "nuclear
winter" that darkened the skies
with a pall of dust and debris that
the creatures could not possibly have
The origins of the big debate began
nearly 30 years ago when the geologist
Walter Alvarez at UC Berkeley and his
father, Luis, a Nobel physics laureate,
proposed that a cosmic collision by
an object from space at least six miles
wide crashed just off Mexico's Yucatan
peninsula about 65 million years ago
and created what is known as the Chicxulub
...Gerta Keller of Princeton University...,
joined by Vincent Courtillot of the
University of Paris and Sunil Bajpai,
of the Indian Institute of Technology,
...insisted that the impact crater
was formed at least 300,000 years before
the great extinction and "caused
no species extinctions" - certainly
not to the dinosaurs. She came to her
conclusion, in part, by age-dating
clusters of mineral spherules that
presumably spewed out of the Chicxulub
crater and landed in Texas, where Keller
said she gathered and tested them.
Instead, she argued, the extinction
coincided with three or four waves
of volcanism in a region of northwest
India known as the Deccan traps....
...Walter Alvarez...rejected the idea
that volcanism in India was the sole
cause of the mass extinction.
..."Few experts on the mass extinction
would agree with Keller that the Chicxulub
impact is older than the mass extinction," he
2008 Mar 25. Theory
on Dinosaurs and Volcanic Activity
65 Million Years Ago. By HENRY
Times. Excerpt: An
asteroid or comet
impact gets most of the credit for
the event that wiped out the dinosaurs
65 million years ago. But massive
volcanic activity around the same
time might have played a role, too,
by pumping enormous amounts of gases
containing sulfur and chlorine into
the atmosphere. An analysis by Stephen
Self of the Open University in Milton
Keynes, England, and colleagues lends
new support to that idea. By looking
at tiny bits of glass that formed
inside the lava flows, they've been
able to reconstruct how much sulfur
and chlorine were released. The volcanic
activity over thousands of years
produced a flood of lava, now known
as the Deccan Trapps, that is thousands
of feet thick over thousands of square
miles of central India. The researchers'
analysis, reported in Science, suggests
the eruption could have produced
...on an annual basis, ...the amount
of SO2 ... at least 10 times greater
than the current amount released
by worldwide volcanic activity. The
environmental impact of that much
gas, they add, was probably severe.
2007 November 6. Rethinking
What Caused the Last Mass Extinction.
By JOHN NOBLE WILFORD. NY Times.
FREEHOLD, N.J. - Splashing
through a shallow creek in suburban
New Jersey, the paleontologists
stepped back 65 million years to
the time of the last mass extinction,
the one notable for the demise
of the dinosaurs. ...At the time,
sea levels were higher and New
Jersey was warmer. The proto-Atlantic
waters reached the center of the
current boundaries of New Jersey,
standing more than 60 feet deep here,
where on a recent day the paleontologists
were up to their ankles in a creek.
They had their eyes on the sediments
in the bank just above the iridium
clay. They call this the Pinna layer.
On previous visits, they had found
in the Pinna rock and soil a surprising
number of marine fossils, including
small clams, crabs and sea urchins.
There was an abundance of ammonites,
considered index organisms of the
uppermost Cretaceous environment.
Somehow, here at least, life appeared
to have not only persisted but also
flourished for tens, perhaps hundreds,
of years after the putative asteroid
..."It is undeniable that the
iridium spike at the base of the
Pinna layer was produced by the impact," Dr.
Landman said. "That's amazing
and makes it hard to explain the
ammonite abundances we find above
the iridium anomaly."
Gerta Keller, a paleontologist and
professor of geosciences at Princeton
University, said the research by
Dr. Landman's group "shows the
complexity of this extinction event
and the difficulty explaining it
by the currently popular impact theory."....
of Past Articles for Chapter