FRACTURED CRUSTTraces of Catastrophe: A Handbook of Shock-Metamorphic Effects in Terrestrial Meteorite Impact Structures
Bevan M. French 1998
_p.18. [We may] regard the impact point as surrounded by a series of concentric, roughly hemispherical SHOCK ZONES, each zone distinguished by a certain range of peak shock pressure ... and characterized by a unique suite of shock-metamorphic effects produced in the rocks. At the impact point, peak shock-wave pressures may exceed ... (1Mbar) for typical cosmic encounter velocities, producing total melting, if not vaporization, of the projectile and a large volume of surrounding target rock. Further outward, pressures of [100-500 kbar] may exist over distances of many kilometers from the impact point, producing distinctive shock-deformation effects in large volumes of unmelted target rock. At even greater distances from the impact point, the peak shock-wave pressures eventually drop to about [10-20 kbar].... At this point, near the eventual crater rim, the shock waves become regular ELASTIC WAVES or SEISMIC WAVES, and their velocity drops to that of the velocity of sound in the target rocks (typically 5-8 km/s). These seismic waves can be transmitted throughout the entire Earth, like similar waves generated by earthquakes and volcanic eruptions. Because of their low pressures, they do not produce any permanent deformation of the rocks through which they pass. However, seismic waves may produce fracturing, brecciation, faulting, and (near the surface) landslides, and the results may be difficult to distinguish from those of normal geological processes.
SEAFLOOR MAGNETIC STRIPESStripes, 4 Apr 03, By Robert J Distinti B.S.EE
46 Rutland Ave. Fairfield Ct 06825
(203)331-9696 contact@distinti.com
distinti.com/docs/riftmaganom.pdfdistinti.com www.youtube.com/user/rdistinti/videos_Page 1 of 11, Rev 1.0
__ABSTRACT_When lava cools in the presence of a magnetic field, such as the Earth’s magnetic field, magnetic material in the lava will acquire the magnetic alignment of the applied field.
_From observation of igneous rock containing magnetic materials, it has been found that some rock beds are magnetized in a direction reverse to the Earth’s magnetic field.
_In order to explain this seeming paradox, a theory was proposed in 1963 by Vine and Matthews in which the magnetic poles of the Earth reverse in a non-periodic fashion every 10,000 to 1 million years (approximately).
_By exploring the cause of the Earth’s Magnetic field, it is discovered that the magnetic field strength of the Earth can and will change over time; however, this change occurs over billions of years and cannot explain the short period (10,000 to 1 million years) shown in the geologic record.
_Instead, it is possible to show that the magnetic reversals in the geologic record can occur without the Earth’s magnetic field changing.
_In fact, the mystery of the alternating magnetic alignment is demonstrated with a simple experiment that any school child can perform.
_This phenomenon is simply what magnets do.
__Ocean rift magnetic anomaly
_We begin our exploration by examining the source of the mystery, the rock created by the separating tectonic plates.
_One such place of plate spreading is located along a feature in the Atlantic Ocean called the mid-ocean rift.
_The rift is located along the centerline of the Atlantic Ocean extending from North to South over almost the entire length of the Atlantic.
_A diagram of a short section of the mid-ocean rift is shown in (Figure 1).
_Point where plates separate and new lava appears Direction of plate spread Direction of Earth’s magnetic field Bands of rock Direction of magnetization Older rock
_Figure 1: Diagram of mid-ocean rift: New molten lava appears where the plates separate.
_The lava contains material that can be magnetized.
_While molten, the magnetic material easily aligns in the direction of any applied magnetic field.
_As long as the magnetic field is present as the lava cools, the lava will retain its acquired magnetic alignment.
_Any material that has a net magnetic alignment is said to be “Magnetized”.
_The term positive magnetization is used to describe rock magnetized in the same direction as the Earth’s magnetic field.
_Negative magnetization is a term used to describe rock magnetized in a direction opposite to the Earth’s Magnetic field.
_Since the sea floor is spreading away from the rift, rock beds farther from the rift represent lava deposited farther back in the Earth’s history.
_Samples taken from these rock beds show that the magnetization of the rock alternates approximately every 10,000 to 1 million years.
_The only explanation for this alternating magnetic alignment in the geologic record is a theory proposed in 1963 by Vine and Matthews in which the poles of the Earth’s reverse on a non-periodic basis.
__Since the above theory requires changes to occur to the Earth’s magnetic field, we shall explore the cause of the Earth magnetic field to see if such a change is possible or even probable.
_The strength of the Earth’s magnetic field is directly related to the speed at which the Earth rotates on its axis.
_The direction of the Earth’s magnetic field is directly related to the direction of rotation.
_This magnetic field relationship to Earth’s spin is true for both New Electromagnetism and classical theories about the source of the Earth’s magnetic field.
_The relationship between a heavenly body’s direction of rotation and its magnetic field is demonstrated by examining the bodies in our solar system.
_The sun and every planet in our solar system (that have been measured) have consistent alignment between spin and magnetic field poles.
_The relationship between the speed of a planet's rotation and the intensity of its magnetic field is also demonstrated by the bodies in our solar system.
_The planet Venus, which has a magnetic field so small that it cannot be measured, rotates so slow that its day is longer than its year.
_Another example is the planet Uranus which seems to have been knocked over on its side.
_Uranus has a polar shift of 97 degrees relative to the plane of its orbit.
_The magnetic field of Uranus is aligned with its spin.
_A curious thing about the magnetic field of the Earth is that it does not align exactly with the rotational axis.
_This is not a large problem when you realize the large quantities of magnetic materials (iron, cobalt etc) are contained in the crust of the Earth.
_Everyone who has experimented with magnets knows that magnetic materials can focus and redirect magnetic fields in much the same way that lenses and mirrors can focus and redirect light.
_This focusing of a magnetic field by magnetic materials is the key to explaining the anomaly in the geologic record.
__Before explaining the anomaly, we must finish our discussion of the Earth’s magnetic field.
_Since the spin of the Earth is one of the factors required to generate our planet's magnetic field, then a reverse in the direction of the Earth’s spin would reverse the direction of the magnetic field.
_Can the spin of the Earth ever change? The answer to this question is found in any introductory astrophysics textbooks which say that tidal forces will cause the rotational energy of a planetary body to eventually be converted to heat.
_This means that a planetary body in orbit around another will eventually come to a state where it does not rotate relative to the other.
_For dissimilar sized bodies, the smaller will succumb first.
_This is what has happened to our moon; have you ever wondered why the Earth always sees the same face of the moon? We never see the “dark side of the moon” because the Earth exerts a very strong tidal force which has depleted the rotational kinetic energy of the Moon.
_This same phenomenon is at work on the planet Venus; however, because the solar tidal forces affecting Venus are much smaller than the tidal effect of the Earth on the Moon; Venus has not yet depleted all of its rotational kinetic energy.
_In a few billion years, one side of Venus will constantly face the sun and one side of the Earth will always face the Moon.
_One day, moon dwellers will ponder about the dark side of the Earth and the strength of the Earth’s magnetic field will dwindle to 1/28th of its current strength.
_At a much later time, solar tidal forces will drain the kinetic energy from the lunar orbit and the Moon and Earth will collide to become one planetary body.
_If the spin of the Earth is slowly dissipated over the years, then the magnetic field of the Earth should only ever be decreasing.
_This would appear as decay in the magnetic alignment of the geologic record and not a periodic reversal.
_Furthermore, these changes occur over billions of years; this cannot explain the short (thousands of years) periodicity of the geologic record.
__The only other known method for drastically changing the spin of the Earth is through collision with another celestial body.
_This is not a likely explanation for the magnetic alignment anomaly since such a collision would cause a greater level of extinction than that which destroyed the dinosaurs.
_Paleontologists have determined that mass extinctions occur periodically about every 32 million years.
_The period between these mass extinctions (even if all are caused by meteor impacts) cannot explain the short periodicity shown in the geologic record.
_Others argue that the magnetic field of the Earth could reverse if the concentrations of ions in the molten strata of the Earth switch in concentration.
_The classical theory holds that the ions in the molten strata of the Earth in conjunction with the spin of the Earth cause the magnetic field.
_Therefore a reversal in ion polarity would indeed reverse the Earth’s magnetic field; however, from an electrical engineering standpoint this is ridiculous.
_If the dynamics of the molten strata of the Earth do cause sufficient charge separation to produce the magnetic field of the Earth, then there should be a measurable electric field emanating from below ground.
_We must remember that electrostatic forces generated from separated charges are about 17^10 times more powerful than the magnetic field produced.
_The Earth would be a strange place if this were indeed the case.
_Simply combing your hair could be dangerous.
_To be sure, there is ionization and charge separation occurring in great quantities in the molten strata of the Earth; however, the distance and period of separation is only sufficient to facilitate the emission and transmission of thermal electromagnetic radiation (heat).
_The high mobility of charge in the molten media ensures that coulomb and magnetic forces annihilate very rapidly.
_There is just no way (that I’m aware of) to produce a sustained Coulomb field in order for the rotation of the Earth to generate a magnetic field from it.
_There might very well be some unknown reason for the reversal of the Earth’s magnetic field; however, this same mechanism should then affect other bodies in the solar system.
_Is it just chance that we live in a time when all bodies in the solar system coincidentally have magnetic field aligned in the same direction relative to their axis of rotation?
__Since it is not likely that the magnetic field of the Earth has ever switched, then there must be a way to explain the reversals of the magnetic alignment (magnetic anomalies) shown in the geologic record.
_In fact there is a very simple explanation that can be demonstrated with a simple experiment.
__Figure 2: The simple experiment setup: N S North Pole N S
_Embedded magnet which represents the source of Earth’s magnetic field
_Styrofoam ball represents the Earth
_Free rotating magnet on surface of ball aligns with the North seeking side pointing North (positive alignment)
__The experiment is constructed by embedding a bar magnet inside a Styrofoam ball.
_The ball represents the Earth and the bar magnet provides a magnetic field which represents the Earth’s Magnetic field.
_Remember, the embedded magnet must have its South seeking pole oriented toward the North Pole of the simulated Earth.
_Next place another bar magnet tangent to the equator of the ball and allow it to freely rotate as shown in Figure 2.
_This free-rotating magnet represents molten lava containing magnetic materials capable of aligning to an applied magnetic field.
_Since the only magnetic field present is from the simulated Earth, the free rotating magnetic will align with its North seeking end pointing toward the North.
_Once the free rotating magnet has stabilized, tape it in place to prevent it from moving.
_Taping the magnet represents lava that has hardened.
_New molten lava is then introduced next to the hardened lava by placing another free rotating magnet next to the immobilized magnet as shown in Figure 3
__Figure 3: N S North Pole N S
_Embedded magnet which represents the source of Earth’s magnetic field
_Styrofoam ball represents the Earth
__New lava is more strongly affected by the previous lava than Earth’s Magnetic field.
__Because of the inverse square nature of magnetic fields, the alignment of the magnetic molecules in the new lava is more heavily governed by the previous bed of lava than the magnetic field of the Earth.
_Since opposite ends of magnets attract, the new lava becomes negatively magnetized.
_The above experiment shows the general behavior of what is happening.
_This theory can only work if it is possible that the rock beds acquire a magnetic field strength (field lines per unit area) greater than the field strength of the Earth present at the point where the rock formed (we use the term “ambient field” for simplicity from now on).
_A logical question: how can rock acquire more magnetization than present in the ambient field?
_Magnetic flux lines, like electricity, seek the path of least resistance.
_A property of magnetic materials which represents the ease at which flux lines can pass through is called permeability.
_A material with a high permeability can “focus” or “concentrate” magnetic fields better than a material with a low permeability.
_Water, sand, mud and air have a very low relative permeability of about 1.
_Because the lava contains minerals such as iron, cobalt and others, it has a higher permeability.
_Iron is 4000 times more permeable than air or water, Cobalt is 60 times and Nickel is 40.
_Even if a sample of lava only contains 1 part per 400 of iron, it can be as much 10 times more permeable than air or water (depending upon how the iron reacts with the other materials).
_This sample of lava could concentrate the magnetic field of the Earth 10 times better than the surrounding media such as the sea water.
_Also, since the mid-ocean-rifts are thousands of miles long, these long bands of molten magnetic material provide the magnetic equivalent of a short circuit to the Earth’s magnetic field.
_Consequently, a piece of this material chiseled from a long deposit of hardened magnetic material is likely to have stronger field strength than the ambient field.
_The following diagram explains how permeable materials concentrate the magnetic field of the Earth.
__Figure 4:
_Magnet Represents source of Earth’s field
__High permeability structure provides a short circuit (shortest magnetic path) for the flux lines.
_This side shows the field of the magnet without the concentration caused by a permeable structure.
_3 times the flux lines pass through a unit area than a corresponding point on the other side of the magnet.
__When tectonic forces fracture the long veins of magnetized materials into “little magnets” (Figure 5), the concentrated magnetic fields of these little magnets are “released”.
_Since magnetic field lines seek the easiest path, the easiest path is through the permeable molten lava emanating from the rift.
_Since the field lines flow from S-to-N inside a magnet and from N-to-S outside, then the magnetic field on the outside of the “little-magnets” is reverse to the field of the Earth.
_Remember that the Earth’s magnetic field flows from the South-pole to the North-pole.
_Since the magnetic field of these “ little-magnets” is stronger than the ambient magnetic field (magnetic field of the Earth present where the rocks form), then the new lava acquires a magnetic field that is greater than, and opposite to the ambient field.
__Figure 5: Tectonic fracturing
_Rift line
_Fracturing of previous lava releases magnetic field that can have a stronger effect on new lava than the magnetic field of the Earth
_Same occurs on this side
_New molten lava
_Direction of magnetization of new lava
_Direction of Earth’s Magnetic field
__Figure 6: This is what magnets do: the alternating pattern represents a lower energy state than when all are in same direction
__Let us make some general observations about this theory to see what aspects can be ascertained.
_1) Since magnetic field strength is an inverse square relationship, the distance from new lava to where the fracturing occurs will affect the strength of the effect on the new lava. The longer the distance the weaker the effect.
_2) Long segments of fractured lava have a farther ranging but weaker effect.
_3) Short segments of fractured lava have a shorter ranging but stronger effect.
_4) Pulverized lava has no appreciable effect.
_5) Since the Earth’s magnetic field is always a component of the magnetic alignment, the reverse aligned lava will generally have a weaker strength than the forward aligned material.
_For example, suppose that the first lava is magnetized to 10 times the strength of the Earth’s field.
_When this first band fractures, it affects the new lava with a field -10 times that of the Earth.
_Since the Earth will add a +1 component, the new lava will have a net magnetization of -9.
_Of course this is a simplistic example.
_The above observations lead us to conclude that there should be more positively aligned lava than negatively aligned lava.
_This is indeed the case.
_This explanation provides the simplest explanation to the mystery of the reversing magnetic alignment of the geologic record.
_The simplest way to prove this theory is to prove that new lava is forming with magnetic alignment reverse to that of the Earth’s magnetic field.
_This will occur where lava is cooling in a negatively aligned magnetic field.
_If there exists a spot on the Earth where a compass can align negative to the field of the Earth (due to rock deposits or other effects), then any lava that is allowed to cool where that compass is will acquire a magnetic alignment reverse to the Earth’s magnetic field.
_This reverse alignment is acquired without reversing the poles of the Earth.
_Conversely, if the reversal of the Earth’s magnetic field was the correct explanation for the geologic record, then it must be the dominant magnetic field effect present when lava cools.
_This means that you could not have cooled lava with acquired field strength greater than the ambient field strength.
_Otherwise, if the magnetic poles of the Earth did reverse, then the stronger field intensity in the rocks would create points on the Earth where a compass would align in the negative direction to the Earth’s field and the pole reversal theory is moot.
_The simple fact that a compass can show a negative reading in spite of the Earth’s field is proof that the lava can acquire field strength greater than the ambient field.
_Furthermore, the field strength acquired by older rock formations is the predominant component affecting the magnetic alignment of new lava.
_As a final note, the field reversal can occur if the original rock bed does not fracture; however, the effect may not be as dramatic.
_The theory proposed in this paper is a more logical explanation of the magnetic anomalies found in the ocean floor than the theory put forward by Vine and Matthews.
_The following sources are used in this paper
gemoc.anu.edu.au/courses/geol3005/jean/GEOL3005/PlateTectonics/Magnetic.htmlEarthquakes
qdl.scs-inc.us/?top=9981 Charles said:
Continental drift is caused by ratcheting effect during earthquakes. The first quake may have been the result of the "shock dynamics" effect. Mike Fischer's model asserts that an impact event at the northern tip of Madagascar set the plates in motion. This model explains so many details about plate movements that it's an excellent place to start. But an instantaneous event would not create the features that could have only emerged after a long period of time, such as magnetic striping on the seafloors centered on the mid-ocean ridges.*15712 So it's more likely that an impact event initiated plate motions, but thereafter, plate ratcheting perpetuates the process.
I think the following [above] from Robert Distinti a few years ago (copied at
cnps.boards.net/post/145/thread ) means that the magnetic field in old lava has a greater effect on the induced field in new lava nearby than does the Earth's magnetic field, because of shorter distance. When new lava forms near old hardened lava, the new lava acquires the reverse magnetic field of the old lava's field. The positive magnetic stripes are stronger than the negative, because the positive add to the Earth's field, while the negative subtract from the Earth's field. So the stripes more likely formed without any reversals of Earth's field. And the stripes likely formed rapidly, rather than over long periods of time, because only during the rapid continental movements would the stripes tend strongly to be parallel.