CHAPTER 1.2
THE STANDARD THEORY

   
CHAPTER 1.2
THE STANDARD THEORY

The purpose of this book is to introduce Ben's Antipodal Impact Theory as the best explanation for the major mass extinctions. However, the best place to begin is to start with an explanation of the Standard Theory of geological formation, regarding the effect of cosmic impacts, continent formation, tectonic plate movement, deep water trenches, subduction, hotspots and island arcs.

While there is no absolute Standard Theory of Geological Formation, there are generally accepted ideas. In this chapter, I will present those generally accepted ideas. 3,4

The Standard Theory views the Earth as having a hard outer crust, varying from a minimum thickness of four miles in deep parts of the ocean where it is denser, to as much as 40 miles in thickness on the continents. The crust is composed of two different types of silicates. The continental tectonic plates are composed of lighter, Felsic rocks, such as granite. The ocean floor is composed of somewhat heavier Mafic material, mostly basalt and gabbro. This outer crust, along with the lithospheric mantle (the hard, brittle part of the mantle), is called the lithosphere.

Below the crust are three other layers (these layers can be subdivided into even finer divisions, theoretically). The three other layers (starting closest to the lithosphere) are:

1. The Mantle—1800 miles thick, composed of four different layers.
a. Upper Lithospheric Mantle -- Separated from the crust by the Mohorovic discontinuity, the Lithospheric Upper Mantle consists of ultramafic rocks that, like the crust, are hard and brittle.
b. Asthenospheric Upper Mantle -- Solid, but ductile ultramafic material.
c. Transitional Mantle -- Ultramafic material.
d. Lower Mantle -- The rock is hot enough to flow ... ultramafic material.


2. The Outer Core—1400 miles thick, composed of molten nickel and iron (relatively heavy).

3. The Inner Core—770 mile radius, composed mostly of solid nickel and iron (even heavier). 109


CONTINENT FORMATION


Relatively little is written about continental formation or continental uplift except to say that:
"During its violent, molten infancy, earth began to settle into layers: The densest elements sank and formed the core, the lightest migrated upward to form the crust, and all the rest ended up in the mantle…" 5

We are left to draw the conclusion that the shapes of the continents are random and that their heights (mountains and high plateaus) are the results of tectonic plate collisions or volcanic uplift (mantle plumes caused by convection currents?).

The felsic material of the continental plates is lighter than the mafic material of the oceanic crust, and therefore, floats higher than the oceanic crust.


THE EFFECT OF COSMIC IMPACTS


The Standard Theory does not regard the effect of cosmic impacts on Earth's surface as significant (except at the impact site) as long as the impact does not penetrate the lithosphere. 6

According to the Standard Theory, the effect of a non-invasive cosmic impact on the Earth is much like that of a bug impact on the windshield of a car, while the car is moving down the highway. Or, at most, the impact would be like a small pebble that might make a slight nick in the glass.

Now this is not to say that the impact site, itself, might not see significant effects. However, the Standard Theory would not expect to see noticeable effects at the antipode of the impact.


TECTONIC PLATE MOVEMENT


There are 12 major tectonic plates on the earth's surface, according to the Standard Theory. The Standard Theory states that many of the earth's geological features can be explained by the movements of these plates (mountain ranges, island arcs, trenches). 4 page 4

Much of the movement of these tectonic plates is caused by sea-floor-spreading at the mid-ocean ridges. The Standard Theory later amends this description to pronounce that sea-floor-spreading is actually caused by subduction of oceanic plates at other locations. The sea-floor-spreading is actually just a passive response to the loss of sea floor being subducted in other locales. Generally the subduction is thought to be initiated by convection currents in the mantle.

SUBDUCTION & DEEP WATER TRENCHES


The Standard Theory states that there are three major types of tectonic plate boundaries. These Boundaries are:
1. Divergent Boundaries—New crust being created as the plates pull away (e.g. the mid-ocean ridges).

2. Transform-Fault Boundaries—Two plates sliding past each other.

3. Convergent Boundaries—Two plates moving into each other. There are three different types of convergent boundaries. They are:
a. Oceanic-Continental Convergence—The oceanic plate pushes into and subducts underneath the lighter continental plate. It also pushes up the continental plate forming mountain ranges and volcanoes (as the subducted plate and water in it is heated to steam and rises).


b. Oceanic-Oceanic Convergence—One of the plates is subducted beneath the other, creating a trench and sub-oceanic volcanoes, resulting in island arcs.

c. Continental-Continental Convergence—Two Continental plates smash into each other and neither one subducts. The rocks are relatively light and resist downward motion. The crust tends to buckle and be pushed upward or sideways. "The collision of India into Asia 50 million years ago caused the Eurasian Plate to crumple up and override the Indian Plate. After the collision, the slow continuous convergence of the two plates over millions of years pushed up the Himalayas and the Tibetan Plateau to their present heights. Most of this growth occurred during the past 10 million years." 3

HOTSPOTS


According to the Standard Theory, a hotspot is a "plume" of lava from deep within the mantle that spews forth lava and creates islands as an ocean plate passes over it. The Hawaiian Islands are part of an island arc (mostly composed of hidden sea mounts) that was created by a hotspot that continues to form more islands. Loihi, the next Hawaiian island, is now forming beneath the surface of the ocean.

It is important to note that the Standard Theory views these hotspots as being fixed in the mantle, with any appearance of movement being due to the movement of the tectonic plate above that hotspot. In explaining the hotspot that fuels the creation of the Hawaiian Islands, www.platetectonics.com writes:
"Geologists believe that a huge column of upwelling lava, known as a "plume" lies at a fixed position under the Pacific Plate. As the ocean floor moves over this "hotspot" at about five inches a year, the upwelling lava creates a steady succession of new volcanoes that migrate along with the plate — a veritable conveyor belt of volcanic islands." 3 page 17


The Standard Theory does not offer a definitive reason for the existence of the plume which causes the hotspot. Some speculation focuses on the possibility that the plume is part of a heat release mechanism from the interior. But the Standard Theory does not offer a definitive explanation.


ISLAND ARCS


Several locations in the ocean feature arcs of islands. Notable among these island chains are the Aleutians, the Kuriles, the Ryukyus and the Philippines, as well as the Indonesian islands and the Solomons.

The Standard Theory sees these island arcs as being created as result of subduction, when certain magmas from the subducted oceanic plate are heated up and rise to the surface to become volcanoes.

These island arcs are regarded as features related to trenches at subduction zones. As for the elegant arc shape of the islands, scientists believe that "it has something to do with the curvature of the earth." 3 page13