Widespread volcanic activity, cyanobacteria and global glaciation may sound like the plot of a new, blockbuster disaster movie, but in reality, they are all events in the mystery surrounding the development of our oxygen-rich atmosphere, according to a Penn State geoscientist.
The most extreme fluctuation in the Earths carbon cycle occurred about 2.2 billion years ago, according to Dr. Lee R. Kump, professor of geosciences and member of the Penn State Astrobiology Research Center, and the conventional explanation is that it marks the debut of our oxygen atmosphere. Recently, however, better geological dating and a better proxy measure of when oxygen occurred in the atmosphere suggest that the oxygen atmosphere appeared long before this supposedly seminal event. "The new dating and proxy clearly show that the rise of oxygen preceded its apparent cause by at least 100 million years," Kump told attendees at the Geological Society of America conference Nov. 8 in Denver.
The proxy measure of when significant oxygen appeared in the atmosphere is sulfur. In an oxygen atmosphere, which is very oxidizing, all sulfur eventually becomes sulfate, but in a reducing atmosphere – one without significant oxygen – sulfur deposits as sulfate, sulfite or even pure sulfur and retains an unusual isotopic signature of upper atmospheric processes. Better dating of these strange isotopes in rocks found them to be 2.3 billion years old or older and does suggest that oxygen appeared earlier than the carbon cycle perturbation.
Andrea Elyse Messer | EurekAlert!
NASA eyes Pineapple Express soaking California
24.02.2017 | NASA/Goddard Space Flight Center
'Quartz' crystals at the Earth's core power its magnetic field
23.02.2017 | Tokyo Institute of Technology
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
24.02.2017 | Life Sciences
24.02.2017 | Life Sciences
24.02.2017 | Trade Fair News