Friday, July 25, 2014
PLACERVILLE, CALIFORNIA
99 CENTS

Rock doc: Sometimes Mother Nature doubles down on death

By
From page A4 | November 07, 2012 |

Not too long ago I rewrote my will. There’s nothing like such a project to remind me of my mortality. But imagine not just your own individual death, but the finality of the death of all the members of your species.

You’ve likely heard of the mass extinction that removed the non-avian (non-bird) dinosaurs from the face of the Earth some 65 million years ago. There have been other periods, too, of enormous “die offs” in Earth history. And even apart from times of mass extinction, some species are always going belly-up. In short, most species that have ever lived are now extinct. As I like to say, extinction isn’t rare, but as common as dirt.

If we look at the fossils that are just a bit older than the time of the dinosaurs’ extinction and compare them to the fossils that are just a bit younger, we can see just how different life on Earth became. Organisms in the oceans were particularly hard hit during the great transition, as were plants on land. Interestingly, mammals were comparatively unaffected (go team!).

The first part of an important theory for what happened when the dinosaurs disappeared was put forward in 1980. The idea was that a large meteorite slammed into the Earth. Later research work put the location of the impact in the Yucatan peninsula of Mexico. The meteorite that hit the Yucatan, as the theory goes, carried with it an unusual metal, one that can be found in a narrow layer of sediment that occurs at or near the “boundary” between the dinosaurs’ era and our own.

Soot and ash in Earth’s atmosphere was so strongly increased by the impact event that not much sunlight reached the surface of the planet. Plants died as a result. After them, of course, many animals dependent on the plants gave up the ghost as well.

But not everyone has been satisfied with the meteorite theory of extinction. There has always been some evidence of massive biological upheavals before the special layer that contains the unusual metal linked to a meteorite impact. Enter Professor Gerta Keller at Princeton who has gone her own way on the matter of what led to the great die-off.

Keller agrees with others in the field that there was a giant impact in the Yucatan. But she argues that mass extinction events occurred before that time. The cause? Massive volcanic eruptions in what’s now India. Those eruptions are just a bit older than the Yucatan impact event. Well, that’s “just” in geologic time — likely 150,000 to 300,000 years.

Keller has taken samples at 150 different places around the globe from the layers just around the time of the mass extinction. She says her observations indicate the mass extinction was well underway before the impact of the meteorite.

As some have said, only a time-travel machine would let us observe what really caused the extinctions of species.  But nothing will stop the good efforts of many scientists to try to understand mass extinctions better.

Dr. E. Kirsten Peters, a native of the rural Northwest, was trained as a geologist at Princeton and Harvard. This column is a service of the College of Agricultural, Human and Natural Resource Sciences at Washington State University. 

Comments

comments

E. Kirsten Peters

.

News

 
Scaffolding issue makes for contentious meeting

By Wendy Schultz | From Page: A1, 2 Comments | Gallery

 
District 2: Candidates debate jobs versus lifestyle

By Dawn Hodson | From Page: A1, 2 Comments | Gallery

Accident: 1 bullet hits 2

By Cole Mayer | From Page: A1

 
 
Help available for breastfeeding mothers

By Health and Human Services Agency | From Page: A3

El Dorado County School Board vacancy

By El Dorado County Office of Education | From Page: A8

 
.

Opinion

Something to think about: More than what you see

By Wendy Schultz | From Page: A4

 
Popular science

By Mountain Democrat | From Page: A4

The weekly Daley: A good time to be there…

By Chris Daley | From Page: A4

 
.

Letters

Support of Director Prada

By Letters to the Editor | From Page: A5

 
Uphold the Third Amendment

By Letters to the Editor | From Page: A5

Bureaucracy

By Letters to the Editor | From Page: A5, 1 Comment

 
Imagination Theater’s play

By Letters to the Editor | From Page: A5

Watch whom you’re calling ‘conservative’

By Letters to the Editor | From Page: A5Comments are off for this post

 
Fake ‘small farms’ steal from residential EID customers

By Letters to the Editor | From Page: A5Comments are off for this post

People of Placerville

By Letters to the Editor | From Page: A5

 
Computer scam phone calls

By Letters to the Editor | From Page: A5

.

Sports

Sports Scene: July 24, 2014

By Democrat Staff | From Page: A6

 
Quarter century later, Rypien wins ACCG again

By Andrew Hazard | From Page: A6 | Gallery

Outside with Charlie: Paddle time

By Charlie Ferris | From Page: A6

 
Midget Lites join tomorrow’s action

By Bill Sullivan | From Page: A6

El Dorado rallies for last-inning victory

By Mike Bush | From Page: A6

 
Rush sit a win from Series

By Jerry Heinzer | From Page: A7

Tasmanian Devils go undefeated

By Patty Pope | From Page: A7

 
.

Prospecting

El Dorado wines win in Amador

By Democrat Staff | From Page: B1

 
Things to do: July 25, 2014

By Democrat Calendar | From Page: B2

Suds entice the taste buds

By Krysten Kellum | From Page: B2 | Gallery

 
Rhythm and Views goes bluesy

By | From Page: B3

Have an Hawaiian vacation at Carson Road wineries

By Carson Road Winery Asociation | From Page: B3Comments are off for this post | Gallery

 
Summer fun is happening in Twain Harte

By Fire On | From Page: B4Comments are off for this post

Manzanita doubles the music

By Table Nectar And Manzanita | From Page: B5

 
Recording artist at Busby Cellars

By News Release | From Page: B6

Hands4Hope hosts school supply drive

By News Release | From Page: B6

 
Supergroup plays Harris Center

By Carrera Productions | From Page: B6

Artists invited to go western

By Art On The Divide | From Page: B7

 
Visit Tahoe artists during tour

By Special to the Democrat | From Page: B7

Reggae on the River celebrates 30 years

By Reggae On | From Page: B7Comments are off for this post

 
.

Essentials

Lake levels 7-24-14

By Michael Raffety | From Page: A2

 
Crime Log: July 11-13

By Cole Mayer | From Page: A2

Building permits 7/7-11/2014

By Michael Raffety | From Page: A2

 
.

Obituaries

Wallace Murrel Thomas

By Contributor | From Page: A2

 
.

Real Estate

How to have a garden party, minus the whining

By Marni Jameson | From Page: HS3

 
Most common mistakes homebuyers make

By Ken Calhoon | From Page: HS4

.

Comics

TV Listings

By Contributor | From Page: A9

 
Speed Bump

By Contributor | From Page: A9

Tundra

By Contributor | From Page: A9

 
Working It Out

By Contributor | From Page: A9

Shoe

By Contributor | From Page: A9

 
Sudoku

By Contributor | From Page: A9

Rubes

By Contributor | From Page: A9

 
New York Times Crossword

By Contributor | From Page: A10

Horoscope, Sunday, July 27, 2014

By Contributor | From Page: A10

 
Horoscope, Saturday, July 26, 2014

By Contributor | From Page: A10

Horoscope, Friday, July 25, 2014

By Contributor | From Page: A10

 
.

Home Source

How to have a garden party, minus the whining

By Marni Jameson | From Page: HS3

Most common mistakes homebuyers make

By Ken Calhoon | From Page: HS4