Delineating primary and secondary organic carbon in neoproterozoic glacial sediments

Jun 16, 2010

How do we begin to understand what early life was like on Earth about 700 million years ago as our planet shifted from an oxygen-free and probably ice-covered realm to the oxygen-rich world that we know today?

One geochemist who decodes the early record of life on Earth has found a method featuring a combination of chemical analyses for a significantly clearer picture of this dynamic environment. Alison Olcott Marshall of the University of Kansas presented her findings today at the Goldschmidt Conference in Knoxville, Tenn. The conference is attended by several thousand geochemists and features new scientific discoveries regarding the Earth, energy and the environment. It is hosted by the University of Tennessee, Knoxville, and Oak Ridge National Laboratory.

Marshall is particularly interested in the time called , a period at the end of the Precambrian Era when geochemists speculate that the world was covered from pole to pole with glacial ice and the existing organisms lived exclusively in water. At that time life was still primarily single-cell organisms. So Marshall looks at chemical fossils to recreate the environment. The chemical complexes left from the cell walls of these organisms are more abundant and more easily classified than body fossils within the samples.

Marshall's research carries her to southeast Brazil, where there is stable sedimentary rock from the late Precambrian era. Her samples come from exploratory drilling that reached eight hundred meters down into the core of black shale that was at
the bottom of a sea 700 million years ago.

"The one caveat with biomarkers (chemical fossils) is that there is always a danger of contamination," Marshall said. Her initial tests using an instrument that looks at by molecular weight often had questionable results due to the possibility of contamination from material of a later period. However, by using another type of high resolution analysis called Raman spectroscopy, she also measured the subtle nuances of vibration that occur at the molecular level. Her high resolution results revealed two previously undetected distinctions in time generations.

Explore further: Magnitude-7.2 earthquake shakes Mexican capital

Provided by University of Tennessee at Knoxville

4.5 /5 (2 votes)
add to favorites email to friend print save as pdf

Related Stories

Looking for signs of early life

Jul 08, 2009

(PhysOrg.com) -- Deciphering the very early history of life on Earth is difficult. In the darkest recesses of the first billion years there are no 'body' fossils - no physical remains. Instead, scientists ...

Recommended for you

Magnitude-7.2 earthquake shakes Mexican capital

Apr 18, 2014

A powerful magnitude-7.2 earthquake shook central and southern Mexico on Friday, sending panicked people into the streets. Some walls cracked and fell, but there were no reports of major damage or casualties.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Skeptic_Heretic
not rated yet Jun 25, 2010
The article should state that "It is speculated that at that time, life was still primarily single-celled organisms" just as they were honest enough to show that the geologists are still speculating.
It is not speculated, it is evidenced. You are speculating that the planet is 6000 years old, regardless of the fact that there is zero evidence for this figure, including within your holy books.

More news stories

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

European climate at the +2 C global warming threshold

A global warming of 2 C relative to pre-industrial climate has been considered as a threshold which society should endeavor to remain below, in order to limit the dangerous effects of anthropogenic climate change.

Finnish inventor rethinks design of the axe

(Phys.org) —Finnish inventor Heikki Kärnä is the man behind the Vipukirves Leveraxe, which is a precision tool for splitting firewood. He designed the tool to make the job easier and more efficient, with ...

Poll: Big Bang a big question for most Americans

Few Americans question that smoking causes cancer. But they have more skepticism than confidence in global warming, the age of the Earth and evolution and have the most trouble believing a Big Bang created the universe 13.8 ...