I have one additional comment since I wrote this and that is that the idea of a crustal imbalance generated by the ice cap build up merits far more attention than it has in the past in light of the apparent readiness of the crust to move at all.
The primary issue we must first overcome is the problem of surface energy release. Obviously, an asteroid that releases all its energy on the surface of the earth will extinguish life long before it imparts enough energy to affect global dynamics. The Cretaceous extinction centered on Yucatan demonstrates this rather vividly. The asteroid involved had an estimated diameter of 20km, a velocity of 10kps and penetrated 30km into the crust. Most of the impact energy was thrown back into the atmosphere.
If however the globe is struck at a high speed by an iron nickel asteroid whose density averages in excess of 5.0 grams/cc, while traveling tangentially to some sub radius of the core we get a different effect. Effective sizes can run from objects with radii of between 5 km to objects with radii of a hundred km. If the object is part of the solar system then the expected impact velocities are not less than 10 kps if originating from the asteroid belt and 30 plus kps if from the Kuiper Belt. However, if the object is not originally part of the solar system the velocity will likely be several times higher. In that case its arrival would also have been from a direction other than the rotational plane of the elliptic. Since the earth is clipping along at about 30 kps and an incoming dense asteroid could be traveling as fast as 70 kps, the combined event velocity could hit 100 kps.
This means an asteroid the same size and density as the Yucatan event would impact with one hundred times the energy as the original. This would probably penetrate the crust. If the density is increased two fold, crustal penetration is certain. Since it would arrive at an angle the penetration distance would be somewhat larger. At this velocity, the atmosphere would be crossed in a second and the crust itself in several minutes as extreme deceleration took place. Critically, the wound left behind would quickly collapse sealing off any rebound energy and limiting direct environmental destruction of the scope experienced at Yucatan.
The asteroid, because of density and speed punches through the crust, which minimizes the extent of horizontal shock. Virtually all its kinetic energy is then released into the core. The observation that a high-speed bullet will leave a small entry hole in the human skull is an appropriate metaphor.
The effect of this impact is to initially rotationally accelerate the core representing perhaps 99% of the earth’s mass in a minute manner. This immediately results in the earth’s crust been temporarily disconnected or at least accelerated away from the core along the crustal plate slip plane. The initial shock of this separation would be felt globally, but been centered deeply in elastic materials it would be cushioned. There would develop a great deal of vertical movement, and one could expect massive new faulting and reopening of old faults. All the generated heat would be initially contained within the core, including that generated by movement friction between the two layers.
Technically, the separation of the core and crust would have occurred on the internal surface of least frictional resistance. Although we assume that this separation was abrupt, this is not absolutely necessary. A short period of elastic stretching could have preceded separation possibly inducing a semi liquid zone because of temperature rise. Also the incoming mass does not need to cross this boundary. It is only necessary for the full energy release to be deep enough to prevent blowback and much orthogonal energy release on the horizontal plane while allowing the compression pulse to continue in same direction. If we assume liquidfication occurred within the boundaries of the pulse, then the energy could have substantially caused additional liquidfication of the movement surface, particularly if that surface is coincident with one of the major density change horizons where orthogonal energy displacement could be forced. In any event, this would all take place deep below the hundred-mile thick and brittle crustal zone. Regrettably, we have little meaningful understanding of the chemical makeup of this environment, let alone its physical behavior.
Fortunately this style of impact event is likely to be generally survivable, since the energy rapidly absorbed by the core can now be released partially back to the crust in the form of slow motion braking energy. All the original energy imparted by the impact is ultimately translated into heat and a modest change in rotational velocity.
The effect on the core by the crust as the two parts try to come back together would then be felt as a steady movement of the crust for a sustained period of time of at least a month or two. The legend of the crust decelerating to a stop and then reaccelerating to achieve a different rotational speed could have happened if the core first flopped over on its poles. The accelerations necessary for the crust to do this in the time frame suggested is impossible to survive. This does not mean however that the process could not have occurred over a much greater and much more likely time span of say two to three months. The lonely legend that we have remembers a reversal rather than precise details, and in any event, is not broadly supported.
The initial surface energy release from possible hundred mile wide penetration of the crust would still be massive, hurling tsunamis in all directions and sending a shock wave in the atmosphere many times around the globe. It almost certainly must have happened in the ocean were the crust is thinnest and the evidence could be buried.
The stressing of the crust would also have probably caused a strong jump in volcanic activity, but we should keep in mind that this activity is more a function of the developing chemistry and heat flow of local volcanoes whose roots are contained within the crust. The heat generated by the event was substantially below these local surfacing hot spots. In fact it is likely that the bulk of the generated heat could well be still down there since heat loss through the crust is extremely slow. One of the difficulties with postulating a heat pump model as the motive power behind plate tectonics is the sheer glacial slowness of it all and the minimal heat release, even along the mid Atlantic ridge.
It would take a long time for the entry hole to be filled by magmas. During this phase the ocean would pour into the hole and be converted into steam with some ash produced by the cubic mile. We would expect months of torrential rain from the steam generated by the ocean pouring into this hole. I observe that the chemical composition of the ash will be rather different from normal volcanic ash since it is partially derived from deep non-crustal rocks. Also, this deeper rock would not necessarily be water saturated, sharply lowering the potential for ash production.
If Iceland were not rather convincingly linked to the development of the mid-Atlantic ridge, I would pick it as our most likely touchdown point. I would even be tempted to try to link the loess deposits of Europe to this event. It is still suspicious enough to justify a careful reassessment. More likely though any such hole is on the ocean bed and is filled with ash and magma making it hard to spot.
I am been too gentle. Geological interpretation is a terribly inexact science. The first accepted efforts in this field came out of the study of European geology. There exists a huge body of relatively unchallenged interpretations that call out for a major effort to reconfirm in the light of modern knowledge and technique.
Having had the pleasure of dealing with geological information for many years, I have learned to be skeptical and to also appreciate how little hard data any given set of eyes will ever see in a lifetime when compared to the total available. This particularly plays real havoc with mapping where continuity is assumed between data points sometimes miles apart. The book has yet to be written describing high-resolution Pleistocene geological depositions for any continent and is in fact still premature.
Besides all this, the possible movement of the crust and its realignment is the real story. The effects on the coast in most parts of the globe would have been devastating with the ocean effectively coming on land and racing hundreds of miles inland. Yet other parts will have been relatively unscathed.
We cannot say a great deal about the dynamics of this purported event. Calculation may give us bounds and perhaps allow us to estimate the level of disturbance. This would still be a unique event in the earth’s history. We can say a lot about how it ended since we live with the end result. The crust itself ended up with the former poles tilted approximately thirty degrees from the new poles on a longitude running through the center of Hudson’s Bay.
There are also additional cultural markers that are global in extent strongly indicating that this was the case. They are argued extensively in Rand flem-Ath and Colin Wilson’s book Atlantis Blueprint previously mentioned. I do not find these markers necessary to the case at hand but they certainly are curious targets amenable to extensive archeological research. If these markers could be proven directly linked to the eras implied, then we can be confident that greater human remnants survived the event sufficient to generate the cohesiveness necessary to leave a record for us to interpret.
However this all happened, the human cost was catastrophic. If it was slow, then the survivors were those who were forced into the wilderness out of their ancestral homes. If quick, one morning an entire civilization of probably millions was extinguished. The only survivors were those at sea and along the axis of movement, only those in the high country. Of course Africa survived hugely. The simple fact that much of Asia was possibly repopulated from founder populations centered on the Caucasus and the Altais speaks to the abrupt elimination of all lowland peoples. This would simply not be possible otherwise since the natural populating process is the other way around. The better we prove a secondary genesis out of central Asia the better we prove the extent of the disaster.