Amara Graps
CHARGED DUST ODYSSEYS -and- DATING OLD EARTH ROCKS
Abstract [1]: Charged Dust Odysseys
Charged Dust:
1. Intrinsic property of matter that occurs in two forms:
positive or negative, dependent on the deficiency or surplus
of electrons carried by fine particles of matter
2. Obligated Trash
3. Loaded Confusion
3. Excited Lint
Odyssey:
1. An extended adventurous voyage or trip.
2. An intellectual quest
The charging of cosmic dust as a topic of study provides
nonintuitive details of the important charge parameter in the
electrodynamics force, which plays a dominant role over the
gravitational force for the Universe's tiny cosmic dust particles.
Cosmic dust particles are rarely electrically neutral because they
are immersed in space plasmas, collecting ions, electrons, residual
high-energy particles, and receiving ultraviolet radiation from
nearby stars. The tiny particles electrically and dynamically
respond to their environment with surface charge potentials which
closely follow the surrounding plasma and magnetic field conditions.
At the same time that the particle charges up, it is responding to
its environment dynamically via the Lorentz electromagnetic force.
Therefore, small cosmic dust particles are ideal tracers of their
astrophysical environments.
A variety of charged cosmic dust populations exist in our solar
system, and in this talk, I will present two. I will present
cirumplanetary dust streams, the Saturnian dust streams in
particular, and describe their possible link to Saturn's E-Ring.
Another population of charged dust is that on the surfaces of
airless bodies such as the Moon and asteroids. What makes an
asteroid an especially attractive dust laboratory, is its fine
regolith embedded in the interplanetary plasma and illuminated by
solar photons. Electrostatic forces have been specifically invoked
as one means by which small grains can be transported across an
airless body's surface in what is known as electrostatic levitation.
To finish the charged dust topic, I will present what are the
necessary inputs for determining an asteroid's dusty electrostatic
environment and what one, such as Lutetia, might look like.
Abstract [2]: Dating Old Earth Rocks
In the geologic time-span from accretion from the solar nebula
(4.54 Ga), through to the beginning of the Archean eon (3.8 Ga),
the planet Earth formed and differentiated. Chemical and physical
processes such as mantle convection, tectonic-plate recycling and
magma generation through partial melting should have scrambled, if
not erased, any coherent geochemical signature of the primordial
material [D. Graham, 2010]. Even if a vestige of such material
remained, it seems unlikely that it would be found in any samples
from Earth's surface or the shallow subsurface that are available
to geologists. Or so it was generally thought.
One such location on the Earth's surface is Baffin Island, Canada.
On the basis of a trace-element and isotopic study, Jackson et al.,
2010 proposed that lavas from this region were derived from a
deep-Earth reservoir that has remained isolated since the earliest
days of planetary accretion some 4.5 billion years ago. Their work
relies on combined analyses of the isotopes of helium, lead,
neodymium and hafnium. Collectively, the results are the first of
their kind for terrestrial volcanic rocks. Another such location on
Earth's surface is the Dresser Formation, Western Australia. While
one billion years younger (say) than Baffin Island, it provides a
more intriguing glimpse of our Earth's history. It includes rocks
with chemical signatures indicative of life, and is now thought to
possibly have ancient atmosphere trapped in quartz fluid inclusions
from the Archean period. As one of the oldest sedimentary-volcanic
units, accurate ages of specific rocks from this region can help
refute or support new solar system dynamical model revisions of the
timing and source regions for a period known as the Late Heavy
Bombardment (LHB).
The Late Heavy Bombardment (LHB) is thought to be a solar
system-wide barrage of comets and asteroids that produced many young
lunar basins; showing a spike in the size-frequency-distribution of
craters that started about 3.9 Ga and which lasted about 200 My.
Meanwhile, on the Earth, it was thought that large-scale LHB impact
signs were erased due to the resurfacing processes of plate
tectonics. Many lines of evidence are pointing to a revised view of
the LHB that these timing and erasing assumptions are probably
wrong. A new modification of the LHB has been proposed by Bottke, W.
et al, 2011, which proposes an "E-belt", which is a hypothesized
extension of the primordial asteroid belt between 1.7-.1 AU. The
E-belt could have produced an extended LHB-era. Dating our Baffin
Island and Dresser Formation rock samples using an alternate
geochronology system would not only calibrate our system, built by
F.S. Anderson (SwRI) and up-and-running, but provide another set of
data to apply to the new modified LHB concept.
Charged Dust:
1. Intrinsic property of matter that occurs in two forms:
positive or negative, dependent on the deficiency or surplus
of electrons carried by fine particles of matter
2. Obligated Trash
3. Loaded Confusion
3. Excited Lint
Odyssey:
1. An extended adventurous voyage or trip.
2. An intellectual quest
The charging of cosmic dust as a topic of study provides
nonintuitive details of the important charge parameter in the
electrodynamics force, which plays a dominant role over the
gravitational force for the Universe's tiny cosmic dust particles.
Cosmic dust particles are rarely electrically neutral because they
are immersed in space plasmas, collecting ions, electrons, residual
high-energy particles, and receiving ultraviolet radiation from
nearby stars. The tiny particles electrically and dynamically
respond to their environment with surface charge potentials which
closely follow the surrounding plasma and magnetic field conditions.
At the same time that the particle charges up, it is responding to
its environment dynamically via the Lorentz electromagnetic force.
Therefore, small cosmic dust particles are ideal tracers of their
astrophysical environments.
A variety of charged cosmic dust populations exist in our solar
system, and in this talk, I will present two. I will present
cirumplanetary dust streams, the Saturnian dust streams in
particular, and describe their possible link to Saturn's E-Ring.
Another population of charged dust is that on the surfaces of
airless bodies such as the Moon and asteroids. What makes an
asteroid an especially attractive dust laboratory, is its fine
regolith embedded in the interplanetary plasma and illuminated by
solar photons. Electrostatic forces have been specifically invoked
as one means by which small grains can be transported across an
airless body's surface in what is known as electrostatic levitation.
To finish the charged dust topic, I will present what are the
necessary inputs for determining an asteroid's dusty electrostatic
environment and what one, such as Lutetia, might look like.
Abstract [2]: Dating Old Earth Rocks
In the geologic time-span from accretion from the solar nebula
(4.54 Ga), through to the beginning of the Archean eon (3.8 Ga),
the planet Earth formed and differentiated. Chemical and physical
processes such as mantle convection, tectonic-plate recycling and
magma generation through partial melting should have scrambled, if
not erased, any coherent geochemical signature of the primordial
material [D. Graham, 2010]. Even if a vestige of such material
remained, it seems unlikely that it would be found in any samples
from Earth's surface or the shallow subsurface that are available
to geologists. Or so it was generally thought.
One such location on the Earth's surface is Baffin Island, Canada.
On the basis of a trace-element and isotopic study, Jackson et al.,
2010 proposed that lavas from this region were derived from a
deep-Earth reservoir that has remained isolated since the earliest
days of planetary accretion some 4.5 billion years ago. Their work
relies on combined analyses of the isotopes of helium, lead,
neodymium and hafnium. Collectively, the results are the first of
their kind for terrestrial volcanic rocks. Another such location on
Earth's surface is the Dresser Formation, Western Australia. While
one billion years younger (say) than Baffin Island, it provides a
more intriguing glimpse of our Earth's history. It includes rocks
with chemical signatures indicative of life, and is now thought to
possibly have ancient atmosphere trapped in quartz fluid inclusions
from the Archean period. As one of the oldest sedimentary-volcanic
units, accurate ages of specific rocks from this region can help
refute or support new solar system dynamical model revisions of the
timing and source regions for a period known as the Late Heavy
Bombardment (LHB).
The Late Heavy Bombardment (LHB) is thought to be a solar
system-wide barrage of comets and asteroids that produced many young
lunar basins; showing a spike in the size-frequency-distribution of
craters that started about 3.9 Ga and which lasted about 200 My.
Meanwhile, on the Earth, it was thought that large-scale LHB impact
signs were erased due to the resurfacing processes of plate
tectonics. Many lines of evidence are pointing to a revised view of
the LHB that these timing and erasing assumptions are probably
wrong. A new modification of the LHB has been proposed by Bottke, W.
et al, 2011, which proposes an "E-belt", which is a hypothesized
extension of the primordial asteroid belt between 1.7-.1 AU. The
E-belt could have produced an extended LHB-era. Dating our Baffin
Island and Dresser Formation rock samples using an alternate
geochronology system would not only calibrate our system, built by
F.S. Anderson (SwRI) and up-and-running, but provide another set of
data to apply to the new modified LHB concept.
