Masih percaya diakhir tahun 2012 ini allah takhayul itu menciptakan Adam dari
tanah liat betul-betul dungu.
Dungu kayak anjing.
Penelitian ilmuwan sudah begitu jauh...
Web address:
http://www.sciencedaily.com/releases/2012/12/
121210133500.htm
Mining Ancient Ores for Clues to Early Life
Dec. 10, 2012 An analysis of sulfide ore deposits from one of the world's
richest base-metal mines confirms that oxygen levels were extremely low on
Earth 2.7 billion years ago, but also shows that microbes were actively feeding
on sulfate in the ocean and influencing seawater chemistry during that
geological time period.
The research, reported by a team of Canadian and U.S. scientists in Nature
Geoscience, provides new insight into how ancient metal-ore deposits can be
used to better understand the chemistry of the ancient oceans -- and the early
evolution of life.
Sulfate is the second most abundant dissolved ion in the oceans today. It comes
from the "rusting" of rocks by atmospheric oxygen, which creates sulfate
through chemical reactions with pyrite, the iron sulfide material known as
"fool's gold."
The researchers, led by PhD student John Jamieson of the University of Ottawa
and Prof. Boswell Wing of McGill, measured the "weight" of sulfur in samples of
massive sulfide ore from the Kidd Creek copper-zinc mine in Timmins, Ontario,
using a highly sensitive instrument known as a mass spectrometer. The weight is
determined by the different amounts of isotopes of sulfur in a sample, and the
abundance of different isotopes indicates how much seawater sulfate was
incorporated into the massive sulfide ore that formed at the bottom of ancient
oceans. That ancient ore is now found on Earth's surface, and is particularly
common in the Canadian shield.
The scientists found that much less sulfate was incorporated into the 2.7
billion-year-old ore at Kidd Creek than is incorporated into similar ore
forming at the bottom of oceans today. From these measurements, the researchers
were able to model how much sulfate must have been present in the ancient
seawater. Their conclusion: sulfate levels were about 350 times lower than in
today's ocean. Though they were extremely low, sulfate levels in the ancient
ocean still supported an active global population of microbes that use sulfate
to gain energy from organic carbon.
"The sulfide ore deposits that we looked at are widespread on Earth, with
Canada and Quebec holding the majority of them," says Wing, an associate
professor in McGill's Department of Earth and Planetary Science. "We now have a
tool for probing when and where these microbes actually came into global
prominence."
"Deep within a copper-zinc mine in northern Ontario that was once a
volcanically active ancient seafloor may not be the most intuitive place one
would think to look for clues into the conditions in which the earliest
microbes thrived over 2.7 billion years ago," Jamieson adds. "However, our
increasing understanding of these ancient environments and our abilities to
analyze samples to a very high precision has opened the door to further our
understanding of the conditions under which life evolved."
The other members of the research team were Prof. James Farquhar of the
University of Maryland and Prof. Mark D. Hannington of the University of Ottawa.
The Natural Sciences and Engineering Research Council of Canada made this study
possible through fellowships to Jamieson and a Discovery grant to Wing.
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Story Source:
The above story is reprinted from materials provided by McGill University.
Note: Materials may be edited for content and length. For further
information, please contact the source cited above.
Journal Reference:
J. W. Jamieson, B. A. Wing, J. Farquhar, M. D. Hannington. Neoarchaean
seawater sulphate concentrations from sulphur isotopes in massive sulphide ore.
Nature Geoscience, 2012; DOI: 10.1038/ngeo1647
Need to cite this story in your essay, paper, or report? Use one of the
following formats:
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McGill University (2012, December 10). Mining ancient ores for clues to early
life. ScienceDaily. Retrieved December 11, 2012, from
http://www.sciencedaily.com /releases/2012/12/121210133500.htm
Note: If no author is given, the source is cited instead.
Disclaimer: Views expressed in this article do not necessarily reflect those of
ScienceDaily or its staff.
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