Magnetism of the Sun/ PaleoMagnetism Flashcards
Intense magnetic field of the sun is associated with
Sunspots
Sunspots also emit hydrogen gas called
Solar Flares
is a plasma which is an ionized gas.
SOlar wind
interaction of the solar wind with the Earth’s magnetic field forms the
Magnetosphere
The
outer boundary of the magnetosphere is the
Bow shock
a region of turbulent motion
Magnetosheath
The geomagnetic field
stretches out on the night side of the Earth forming the
Magnetotail
boundary between the
Earth’s magnetic field and the solar wind is the
Magnetopause
The charged particles that penetrate the magnetopause and are trapped by the Earth’s
magnetic field form the
Van Allen Radiation Belts
Energetic particles cause ionization of molecules of nitrogen and oxygen in the atmosphere
forming an ionized region called the
Ionosphere
The ionosphere is located at an altitude of
about
50 km and 1500 km.
T or F: direction of remanent
magnetization was that of the geomagnetic field during cooling.
True
The apparatus consists of two identical small magnets mounted horizontally at opposite ends of a short
rigid vertical bar so that the magnets are oriented exactly antiparallel to each other.
astatic magnetometer.
is the study of the geomagnetic field recorded in dateable historic artefacts.
Archaeomagnetism
This imaginary magnet has its north pole near the geographic South Pole and its south pole near the geographic North Pole, roughly aligned with the Earth’s rotation axis.
Axial Geocentric Dipole
Axial Geocentric Dipole
Axial Geocentric Dipole
if data are averaged over a long enough interval
of time, the mean paleomagnetic pole position will coincide with the axis of rotation of the Earth.
axial geocentric dipole hypothesis
it is
possible to calculate where the geomagnetic pole would need to be to produce the observed declination
and inclination.
Virtual Geomagnetic Pole
If samples are measured from a large number of recent lava flows covering a long enough period of time,
the mean direction of the collection will correspond to the field of an
axial geocentric dipole
Pole representing an averaged value of the field, is called
Paleomagnetic Pole
_________of a rock
was acquired at the time of formation of the rock (or at a known time in its history), and has since remained
unaltered.
natural remanent magnetization (NRM)
Laboratory techniques must be applied that eliminate the undesirable components and isolate the
primary magnetization. This process is called __________
Magnetic Cleaning
This type of magnetic cleaning can be produced in a coil by passing an alternating current through it.
alternating magnetic field
when a rock sample is heated to a given temperature T, magnetic components that have lower
blocking temperatures than T are _________
Thermally Randomized
T or F: paleomagnetic sampling includes a field test that can establish the stability of the demagnetization over geological time.
False
It is applied to samples taken from
beds that were originally horizontal and have been tilted by later tectonic effects.
Fold Test
If the magnetization was acquired by the rock after it was folded, it will have a uniform direction at all
points of the fold
Post Folding Magnetization
If the paleomagnetic direction in the rock is stable, it will experience the same rigid-body rotation as the
tilted strata; its direction will vary around the fold
prefolding magnetization
If magnetization is acquired during the tectonic event; this case the direction of magnetization changes
around the fold but by a smaller amount than the folding
(synfolding magnetization)
T or F: Suppose we are investigating a limestone formation and that we discover a conglomerate containing
cobbles of the limestone. their paleomagnetic directions, if stable, should be evenly distributed.
False
During intrusion of a dike or sill the adjacent layers of the host rock are baked by contact with the hot
lava and acquire a TRM when they cool.
Baked Contact Test
If samples taken from the lava and contact zone of the host rock have the __________ magnetization direction .
Same
This test can be applied when the paleomagnetic samples represent a large enough time
interval (>10 ka) to have recorded normal and reversed polarities of the magnetic field
Reversals Test
T or F: presence of an unremoved secondary component will give resultant normal and reversed directions
that are no longer antiparallel.
True