Navigation Links
Extinction by asteroid a rarity
Date:10/7/2008

In geology as in cancer research, the silver bullet theory always gets the headlines and nearly always turns out to be wrong.

For geologists who study mass extinctions, the silver bullet is a giant asteroid plunging to earth.

But an asteroid is the prime suspect only in the most recent of five mass extinctions, said USC earth scientist David Bottjer. The cataclysm 65 million years ago wiped out the dinosaurs.

"The other four have not been resolvable to a rock falling out of the sky," Bottjer said.

For example, Bottjer and many others have published studies suggesting that the end-Permian extinction 250 million years ago happened in essence because "the earth got sick."

The latest research from Bottjer's group suggests a similar slow dying during the extinction 200 million years ago at the boundary of the Triassic and Jurassic eras.

At the 2008 Joint Annual Meeting of the Geological Society of America, USC doctoral student Sarah Greene drew similarities between ocean conditions at the Triassic-Jurassic boundary and after the end-Permian extinction.

At both those times, bouquet-like structures of aragonite crystals formed on the ocean floor. Such structures are extremely rare in Earth's history, Greene said.

"The fact that these deposits have only been found at these two specific times that are associated with mass extinction suggests at the very least that maybe there's some shared ocean geochemistry that could be related to the cause of the extinctions," Greene said.

"The Triassic-Jurassic extinction cause is totally up for grabs at the moment," she added.

Also at the meeting, USC doctoral student Rowan Martindale presented results from her studies of coral reefs during the Triassic-Jurassic extinction.

"The coral reefs look actually very similar to modern coral reefs," she said. "At the end-Triassic mass extinction, you lose all your reef systems. And nobody's figured out why that is."

Martindale identified two distinct types of ancient reefs: one dominated by coral and another consisting mainly of mud and debris, possibly held together by bacteria.

A theory for the end-Triassic extinction needs to explain how both types of reefs could have been killed off, Martindale said.

Any knowledge about end-Triassic reef death could be useful in understanding the current reef crisis, widely attributed to climate change.

"We're looking at it as a model to give us any insight that we might have for today's decline for coral reefs," Bottjer said.


'/>"/>

Contact: Carl Marziali
marziali@usc.edu
213-740-4751
University of Southern California
Source:Eurekalert

Related biology news :

1. Mass extinctions and the evolution of dinosaurs
2. Study of islands reveals surprising extinction results
3. A recipe for saving the worlds oceans from an extinction crisis
4. Extinction most likely for rare trees in the Amazon rainforest
5. Oceans on the precipice: Scripps scientist warns of mass extinctions and rise of slime
6. Smithsonian hosts tropical extinction debate in Panama
7. Rare Antarctic fossils reveal extinction of tundra before full polar climate arrived
8. Ivory poaching at critical levels: Elephants on path to extinction by 2020?
9. Newly discovered monkey is threatened with extinction
10. 1/3 of reef-building corals face extinction
11. The mystery of mass extinctions is no longer murky
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/16/2017)... May 16, 2017  Veratad Technologies, LLC ( www.veratad.com ... age and identity verification solutions, announced today they will ... 2017, May 15 thru May 17, 2017, in ... International Trade Center. Identity impacts the ... in today,s quickly evolving digital world, defining identity is ...
(Date:4/18/2017)... April 18, 2017  Socionext Inc., a global expert in SoC-based ... edge server, the M820, which features the company,s hybrid codec technology. ... by Tera Probe, Inc., will be showcased during the upcoming Medtec ... show at the Las Vegas Convention Center ... Click here ...
(Date:4/11/2017)... Research and Markets has announced the addition of the ... ... to grow at a CAGR of 30.37% during the period 2017-2021. ... been prepared based on an in-depth market analysis with inputs from ... prospects over the coming years. The report also includes a discussion ...
Breaking Biology News(10 mins):
(Date:5/23/2017)... ... May 23, 2017 , ... Customers often prefer ... again and again. METTLER TOLEDO has released two new videos that show how ... integration of the ACT350 into Siemens and Allen Bradley PLCs is easy and ...
(Date:5/21/2017)... (PRWEB) , ... May 19, 2017 , ... ... meeting and educational conference of the American Association of Bioanalysts (AAB) and the ... Hotel in Houston. The conference reinforces AAB’s commitment to excellence in clinical laboratory ...
(Date:5/18/2017)... Mass. (PRWEB) , ... May 18, 2017 , ... ... the procedure on April 28, 2017 at the Prince Of Wales Private Hospital. ... cervical disc at level C6-C7. The patient failed conservative treatments prior to undergoing ...
(Date:5/18/2017)... , ... May 17, 2017 ... ... standards with psychonneuroendocrine stress expertise, and further enhances its scientific power by ... Douglas A. Granger, Ph.D., has agreed to join the scientific advisory board. ...
Breaking Biology Technology: