© Lloyd, Charles Chandler

 

The high cliffs that run along the left edge of East Antarctica in the image below are an unusual mountain range. These Transantarctic Mountains were not formed by lateral compression but by curling up.13 It suggests that East Antarctica was formerly part of a larger whole that was clipped along the line of the mountains, as proposed in this scenario. Also, the big difference in thickness between West (25 km) and East (40 km) Antarctica12, clearly apparent in this image, suggests that they did not originate together but were brought together.

At the center of East Antarctica are the Gamburtsev Subglacial Mountains (GSM). In a study using seismic tomography, "no evidence is found for a significant thermal anomaly beneath the GSM, precluding the existence of a Cenozoic hotspot". The data "indicate little change in lithospheric thickness beneath the GSM and surrounding regions." In the opinion of the researchers, "uplift is attributed to one or more Proterozoic compressional orogenic events". "For example, the Petermann Range in central Australia represents the remnants of a... compressional intraplate orogeny".4 In other words, a strong compressive force in ancient times raised the mountains in central Antarctica, similar to what happened to Australia. Presentation 6 shows how the Shock Dynamics meteorite impact formed the Petermann Range and the Bight in Australia. In the same way, the impact of the planetesimal on Antar formed the Gamburtsev Subglacial Mountains.


The Atlantic ridge is an example of slow spreading.

The Pacific is an example of fast spreading.

Plate tectonics, on the other hand, states that entire plates are separating. "As the oceanic plates separate at the mid-ocean ridge spreading centers, partial melting of the upwelling mantle creates enough magma to form a layer of basaltic crust 6 to 7 km thick."2

Whether that is so can be determined by a look at the melt regions beneath the spreading ridges. The popular notion is that magma is rising up all along the ridge. However, "no magma chamber reflectors have been imaged at slow-spreading ridges"1,5,9 such as the Mid-Atlantic Ridge, although there are random volcanic eruptions. At fast-spreading ridges such as the East Pacific Rise, magma chambers are found in segments along the ridge, but they are quite small and only in the upper crust. A column of partial melt is below them in the lower crust. "Models of oceanic crustal generation must account for the efficient delivery of melt through the lower crust to a small upper crustal magma chamber."15 A tomographic study shows that globally, low-velocity zones (indicating at least partial melt) beneath mid-ocean ridges extend only to about 100 km depth.3 For the Mid-Atlantic Ridge, "the melt source region lies at a depth of 50-100 km below sea level", and there is "no evidence... of any clear conduit or connection between the mantle melt source and the crustal magma body"8 where volcanism occurs. "Basaltic melt is present beneath the East Pacific Rise spreading center in a broad region several hundred kilometers across..., not just in a narrow region".2 This region of melt is skewed to the west. "The lowest velocities do not lie directly under the ridge".2

"Mantle melting beneath ocean ridges is caused by decompression as mantle adiabatically upwells". "More melt is produced from a given parcel of mantle beneath fast-spreading ridges than beneath slow-spreading ridges." "Spreading rate variation is the primary variable that determines both the extent of mantle melting beneath ocean ridges and mid-ocean ridge basalt chemistry."6 This seems odd, considering that the difference in speeds is between 2.5 and 11 centimeters per year.6 And yet "all these types of ridges produce crust of 6-7 km thickness, except for those with extremely low half-spreading rates (less than 0.5 cm per year), where it is thinner"11 such as in the Arctic.

Geologists talk about oceanic crust in 3 layers. Layer 1 is fairly thin sediment. The upper part of Layer 2 (called 2A) is 0.5 km-thick basaltic lava in the form of 'pillow basalt' (fine-crystal or glassy basalt that cooled quickly). The lower part (called 2B) is 1.5 km-thick diabase (medium-size crystal basalt that cooled more slowly) intrusive dikes (fairly vertical sheets of solidified magma). Layer 3 is 4-5 km-thick gabbro (coarse crystal basalt that cooled slowly).

"Basaltic dikes are nearly 1 meter wide, on average, across all oceanic spreading centers"9 regardless of spreading speed. This seems odd because dike width "should scale with... ridge spreading rate." "The most feasible explanation for this discrepancy is that the magma supply from the magma chamber is limited, so that the magma pressure drops as the dike propagates."9

The evidence of tiny or non-existent magma chambers under spreading ridges that encompass the world suggests that spreading ridges are the remains of past events, things that formed long ago and are not great seams of upwelling today. As weak zones in the oceanic crust, they are subject to stress from differential rotation between the lithosphere and mantle, as well as from other forces, producing limited volcanism and earthquakes. In the Shock Dynamics paradigm, the speed of Antar was considerably faster, because of the greater force-to-mass ratio, than that of continents separating after the Shock Dynamics impact. This produced the distinct "fast spreading" ridge with extremely long transform faults and higher melt volume. But since both events were limited to altering the surface of the oceanic crust, Layer 3 was undisturbed and the magma supply to dikes was universally small for both, being surface melt from pressure and pressure-relief melting.

The ridge reaching from the East Pacific Rise to the Southeast Indian Rise is illustrated below. The bars show the directions that transform faults extend from the ridge, and thus the trend of spreading. Following this scenario, the white bars indicate parts of the ridge where side strips of Antar passed over the seafloor. Those that went east are now accreted (attached by collision) to the west coast of North America. Those that went south are now accreted to South America. This material would have ended up west of Africa. Accretion to North and South America would have occurred as these landmasses moved west following the Shock Dynamics impact, accumulating the material like bugs on a car grill. A strip of this material on North America's west coast, from Vancouver Island to Baja California, appears to have slid north a few hundred miles with North America's slight counterclockwise rotation.

The red bars mark the likely path of the largest part of Antar, which became East Antarctica. These sections of the ridge are by far the most dramatic in the world for length and definition of transform faults, and are associated with so-called megatrends of seamount chains and fracture zones. Two prominent megatrends are shown in yellow below.

There are many thousands of seamounts on the Pacific seafloor. Crudely speaking, they are pimples where hot magma has pushed to the surface. On a small scale, one can compare them to bubbles of boiling mud above hot springs.

Following this scenario, the portion of the Pacific seafloor nearest to the impact of the planetesimal was heated the most, producing the most seamounts. The largest piece of Antar (East Antarctica) pulled a film of hot surface seafloor crust behind it, so seamounts should follow its path in diminishing numbers. The map (below) of seamount density14 on the Pacific plate shows that to be so, with a northwest-southeast axis.

Together, these features suggest a path for East Antarctica represented by the shaded area below. Note that the Shock Dynamics event happened much later, and thrust new landmasses and features into the western part of the shaded area, such as the Izu-Bonin and Marianas Trenches, Japan, parts of Asia and Southeast Asia, Australia, New Zealand, the Tonga-Kermadec Trench, etc. The Emperor-Hawaiian chain is also associated with the Shock Dynamics event, in particular the movement of Alaska along the line of the Aleutian Trench.

East Antarctica (Antar) fits the bulge in the East Pacific Rise nicely, as shown below.

It is plausible that the force of impact of the planetesimal was sufficient to tip the Earth 23.5 degrees from the plane of the ecliptic. Because this was the same impact that set Antar in motion, the sudden tipping may have led to the bend in Antar's path.