by Randy Boswell
Canwest News Service
November 25, 2008
A new geological study
rocks actually involved in
tandem with plants and animals.
A landmark scientific study co-authored by a Canadian geologist has
identified a sudden explosion of mineral diversity after the
emergence of life on Earth, and advanced a "revolutionary" theory
that rocks have been evolving - much like plants and animals -
throughout the planet's history.
Wouter Bleeker, an Ottawa-based researcher with the
Geological Survey of Canada, is one of eight members of an
international team whose theory of "mineral evolution" - the idea
that many of the Earth's rocks are dynamic "species" which emerged
and transformed over time, largely in concert with living things -
is generating a major buzz in the global scientific community since
its publication last week in a U.S. journal.
"The key message," Mr. Bleeker told
Canwest News Service, "is how closely intertwined the mineral
world is with life and biology."
He said human teeth - with their key
ingredient of apatite - are vivid reminders that the "seemingly
static, inorganic" physical Earth should be viewed more like a
"living organism" underpinning the biosphere.
But the new theory is also being hailed as a potential tool in the
search for life on other planets since it offers new ways of
perceiving the interactions between rocks and living things.
Probes of distant planets should be
seeking evidence of biological processes that may have shaped alien
landscapes, the scientists contend.
The study (Mineral
Evolution), published in the latest edition of American Mineralogist,
chiefly proposes a new way of understanding Earth's natural history
and teaching the geosciences - particularly how plant processes have
altered the planet's atmosphere and its rock chemistry, and how the
rise of complex life forms with shells and skeletal features,
"irreversibly transformed Earth's
The research team, led by U.S.
geologists Robert Hazen and Dominic Papineau of the
Washington, D.C.-based Carnegie Institution, recounted how just 12
minerals are believed to have been present among the dust particles
swirling through space at the dawn of planetary formation some five
billion years ago.
As the materials that formed Earth "clumped" together and were
subject to thermal pressures and other forces, the number of
distinct minerals increased to about 250, the study says.
Then, due to volcanic activity, plate
tectonics and other processes that churned the surface of the planet
before life emerged, the population of mineral "species" had grown
to about 1,500 by four billion years ago.
That's when changes to ocean chemistry and atmospheric conditions,
coupled with the emergence of life, sparked an unprecedented
diversification of the world's minerals.
Among the best known examples of how living things transform the
Earth's rock layers is limestone, which is accumulated from the
dissolved shells of tiny marine creatures.
But the new study provides the first
comprehensive analysis of the multitude of rock-life interactions
and documents how mineral evolution unfolded rapidly as life took
hold early in the planet's history.
"Biochemical processes may thus be
responsible, either directly or indirectly, for most of the
Earth's 4,300 known mineral species," the study states.
"Mineral evolution is obviously different from Darwinian
evolution - minerals don't mutate, reproduce or compete like
living organisms," said Mr. Hazen in a statement announcing the
"But we found both the variety and
relative abundances of minerals have changed dramatically over
more than 4.5 billion years of Earth's history.
"For at least 2.5 billion years, and possibly since the
emergence of life, Earth's mineralogy has evolved in parallel
with biology," Mr. Hazen added.
"One implication of this finding is
that remote observations of the mineralogy of other moons and
planets may provide crucial evidence for biological influences
Stanford University geologist Gary
Ernst is quoted in a Carnegie Institution summary of the study
describing the research as "breathtaking" in its scope and adding
"the unique perspective presented in
this paper may revolutionize the way Earth scientists regard
The study's proposed theory of mineral
evolution is also highlighted in the latest edition of Nature as,
"an exciting concept that will do
much to stimulate debate and enliven thinking in the usually
staid field of mineralogy."