Essay 6

by Ben Fishler

The current theory, when pressed, explains the 120 mile diameter area of volcanism detected below the surface of southern Georgia as an "ancient volcano complex from the Triassic period" (201 - 252 MYA). It is assumed that the volcanism may have something to do with the Central Atlantic Magmatic Provinces that were created around 201 MYA. However there is no linkage between this huge volcanic remnant and any other volcanism. It is just off by itself. This is not normal.

Smaller eruptions of volcanism can occur almost anywhere, but large, impressive volcanic sites like this one only occur under specific circumstances. Huge volcanic remnants can be formed by three different processes. These are:

1. DIVERGENT PLATE SPREADING — This occurs when two tectonic plates are moving apart. There is a line of volcanic separation between the two plates with major intermittent volcanism present. This can be seen in Iceland and along the Mid-Atlantic Ridge in particular.

2. CONVERGENT PLATE SUBDUCTION — This occurs when one tectonic plate is subducted beneath another tectonic plate. The subducted plate carries water-laden crust down into the mantle, where it heats up and turns the water into steam at 500+ times the volume of water, leading to explosive volcanism at the surface. This process forms a string of volcanic mountains that are located within a few hundred miles of the subduction line. Examples of these are the Cascades on the west coast of the US (think Mount St. Helens) and the Andes in South America.

3. HOTSPOT VOLCANISM — According to the current theory, when a tectonic plate passes over a mantle plume, it experiences hotspot volcanism, which can be rather mild (Hawaii) or intermittantly explosive (Yellowstone). Either way there is a trail of old volcanoes or seamounts showing the past path of the volcanism.

These are the three ways that large volcanic remnants are formed. All three of these processes are connected with a telltale trail of volcanic remnants. None of them exist in isolation … except in southern Georgia. Well, maybe there's more to the story than the current theory understands. Maybe it isn't an ancient volcano complex. Maybe it's a mascon.

A mascon is a concentration of mass that rises up from the heavier mantle material to fill a void created by an impact object entering and moving through the mantle. Originally, my theory posited that somewhere in southern Georgia, northern Florida or southern Alabama there should be a mascon from the dinosaur-killing asteroid from 66 MYA. I believed that the asteroid penetrated the Earth's crust and created a void in the mantle as it traveled towards the underside of Australia and New Zealand.

When I found that that there was actually an "ancient volcano complex" covered with an unusual sandstone layer in southern Georgia, I realized this was probably the mascon that I was looking for … especially since non-sulfurous Vidalia onions would grow in the sandstone area to the northeast, but could not be grown in the re-sulfurized area where this mascon was located.

I believe that the volcanism from the mantle material will date to 66 MYA or younger, whereas the evolutionary track of the foraminifera in the sandstone willl date to 66 MYA or older. This directly contradicts the current theory, which expects the volcanism to date to 201-252 MYA, while the sandstone would be younger and gradually even younger as it gradually accumulated through the ages.
I believe that the sandstone came in all at once from a tsunami that was created by the impact, filling much of the crater before the mantle had a chance to respond to the void. Thus there would be older sandstone on top of younger volcanism.