The purpose of this book is to
introduce Ben's Antipodal Impact Theory as the best explanation for the major
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. This outer crust is called the lithosphere.
Below the lithosphere 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 Mantle1800 miles
thick, composed mostly of molten silicates (relatively light material).
2. The Outer Core1400 miles thick, composed of molten nickel and
iron (relatively heavy).
3. The Inner Core770 mile radius,
composed mostly of solid nickel and iron (even heavier).
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?).
Furthermore, the reasons for a
relatively flat continental shelf, then a relatively steep (4 degrees to 25
degrees) bank then a relatively flat ocean floor (rather than a constantly
sloping bank with no shelf and no flat floor) are not even addressed.
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.
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
BoundariesNew crust being created as the plates pull away (i.e. the
mid-ocean ridges).
2. Transform-Fault BoundariesTwo plates
sliding past each other.
3. Convergent BoundariesTwo plates
moving into each other. There are three different types of convergent
boundaries. They are:
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a.
Oceanic-Continental ConvergenceThe 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
ConvergenceOne of the plates is subducted beneath the other, creating a
trench and sub-oceanic volcanoes, resulting in island arcs.
c.
Continental-Continental ConvergenceTwo 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.
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
These island arcs are regarded as
features related to trenches at subduction zones. |