This is the online edition of In the Beginning: Compelling Evidence for Creation and the Flood, 8th Edition (2008), by Dr. Walt Brown. It is designed to be read online.
Copyright © 1995–2008, Center for Scientific Creation. All rights reserved.
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Theories Attempting to Explain the Origin of Ocean Trenches
Two broad theories include explanations for the formation of ocean trenches. Each explanation will be given as its advocates would. Then we will test these conflicting explanations against physical observations and the laws of physics.
Figure 1: Hydroplate Explanation for Trenches. (A) Before the flood, the weight of rock and water, pushing down on the subterranean chamber’s floor, balanced the floor’s upward pressure. The rupture destroyed that equilibrium. Directly below the rupture, the imbalance grew as escaping, high-velocity water and the crumbling of unsupportable walls widened the globe-encircling rupture hundreds of miles. Eventually, the imbalance overwhelmed the strength of the floor. First, the Mid-Atlantic Ridge buckled, or sprang, upward. As Europe, Africa, and Asia slid eastward and the Americas plate slid westward (based on today’s directions), weight was removed from the rising floor, causing it to rise faster, and accelerating the hydroplates even more. Pressure directly under the floor, represented by the large black arrows, naturally decreased as the floor rose.
Figure 82(B) During the flood phase, solid rock in the inner earth began melting and contracting. [For more details, see “Magma Production and Movement” on page 149. Because of this contraction, the crust on the Pacific and Indian Ocean side of the earth (hereafter called the Pacific plate ) settled and fractured, perhaps by as much as 18 miles! 11 Then, during the continental drift phase, the Pacific plate and the mantle below it rapidly subsided toward the Atlantic. That drop steepened the downhill slope of the sliding hydroplates and allowed them to slide into the Pacific region without major obstructions from the already subsided Pacific plate below. Downward buckling and deep faulting formed trenches. Soon, huge volumes of magma began erupting onto the days-old Pacific floor. During the next few years, frictional heating melted much of the inner earth. All this melting lubricated the shifts inside the earth and allowed gravitational settling, which released much more heat, increased earth’s spin rate, and converted the inner earth to today’s inner and outer core—monumental changes. The large, thick reservoir of magma that spilled onto the top of the sunken Pacific plate provided most of the heat that drove the ice age and accounts for almost 40,000 volcanoes. Even today, magma breaks out and escapes upward from under the solidifying and contracting lava above. This heats part of the ocean, creating “El Niņo” weather conditions.12
Magma Production and Movement
Magma’s Compressibility. Magma—melted rock inside the earth—is compressible under high pressure. Rock that melts under the extreme pressures near the center of the earth will contract and occupy a smaller volume than it did before melting! At intermediate pressures corresponding to those in the earth’s mantle, melted rock occupies nearly the same volume as the original solid rock. At atmospheric pressure, rock expands by 7–17% when it is heated and melts. The density where the rock’s volume does not change as it melts is called the crossover density. It occurs about 120–300 miles below the earth’s surface. The exact crossover depth depends on the minerals present. Because of magma’s compressibility, magma below this depth is too dense to rise, so magma cannot circulate inside the mantle,15 contrary to what has been taught for 50 years!
Figure 83: Crossover Depth. This graph shows how the density of liquid rock (magma) changes with depth below the earth’s surface. Above the crossover depth, magma is less dense than solid rock at the same depth and will try to rise through the cracks where the magma was produced by sliding friction; below the crossover depth, magma is denser than solid rock and will sink toward the liquid outer core. Magma that drains down into the liquid outer core becomes almost twice as dense as the solid rock at the base of the mantle. [See the highlighted yellow cells on page 448.]
Earth’s magma began to be produced during the flood. [See “Melting the Inner Earth” on pages 446–449.] The magma’s final volume was more than 120 times greater than all the water in today’s oceans! With so much more liquid rock inside the earth than liquid water on earth, we need to understand how magma forms and why it moves.
Where Did All the Magma Go? The denser (deeper) magma and the denser unmelted minerals in the magma slowly fell into what grew to become earth’s outer and inner core, respectively. The less dense magma that formed above the crossover depth tended to escape to the earth’s surface as volcanoes or flood basalts. For years after the flood, most eruptions spilled onto the Pacific floor—a floor littered today with 40,000 volcanic cones, each taller than 1 kilometer! The following analogy explains why.
: Inner Earth. The dashed white line marks the crossover depth. Magma generated above that line is less dense than the surrounding rock and will try to rise to the earth’s surface. Magma generated below that line contracts and becomes denser, so it drains into the outer core (a liquid). Standard explanations for the shifting of continents and for so much liquid 1,800 – 3,200 miles under our feet are full of scientific problems.18 [See “Molten Earth” on page 27; “Plate Tectonics” on page 109; and “Melting the Inner Earth” on pages 446–449.]
A Cable Analogy. Imagine a long, unbreakable cable passing through the center of the earth before the flood. One end is anchored to the portion of the subterranean chamber floor that will rise to become the floor of the Atlantic Ocean. The other end attaches to the Pacific plate on the opposite side of the earth. When the Atlantic floor is forced upward at the end of the flood, the Pacific floor will be pulled down.
Gravity produces the same effect as our imaginary cable. Gravity produces so much compression deep inside the earth that voids cannot open up; rock is always squeezed against rock (including melted rock). However, compressed rock can shear. For example, compress a thick deck of cards horizontally in a vise. (Each card is vertical.) Space cannot open up within the deck, but a relatively small vertical force can cause the cards to slip—or shear. Friction from shearing deep in the earth always melts the sliding surfaces. The magma produced then lubricates those surfaces, so they slip more easily.
Shearing. Now let’s imagine that many evenly spaced cables connect the rising Atlantic floor to the broader, subsiding Pacific plate. (The upward pull from the rising Atlantic floor widens with depth below;16 this is why the Pacific has a larger area than the Atlantic.) These cables shorten by varying amounts, because of magma’s compressibility and the different amounts of frictional heating along their lengths. The farther a cable segment is from the Atlantic floor, the more likely it will move at a different rate than a corresponding segment on an adjacent cable, thereby shearing the rock between them, and produce magma. (Each segment’s movement is the sum of the separate expansions or contractions of all the cable’s segments between that point and the Atlantic floor—plus the movement of the attachment point at the Atlantic floor, so the farther a segment is from the Atlantic floor, the more likely shearing becomes.) Thus, shearing and magma production are extreme in and under the Pacific plate.
Large shearing offsets that reached the Pacific floor formed ocean trenches. Benioff zones under trenches are shearing surfaces (fault planes), not subducting plates, as commonly taught.17 Island chains often formed where magma escaped upward along these cracks. The Hawaiian Islands and the Emperor Seamounts are prime examples.
Deep Movements during the Flood Phase. As the subterranean water escaped during the flood phase, the rupture steadily widened. This removed more and more weight from the chamber floor directly below, so that portion of the floor increasingly bulged upward. Two types of forces resisted the rising of what would become the Atlantic floor: (1) the strength of the rock between that floor and the Pacific side of the earth, and (2) the weight of the stationary hydroplates that still lay above most of what would become the Atlantic floor.
Fractures and melting occurred deeper and deeper beneath the bulging chamber floor on the Atlantic side. Magma produced below the crossover depth contracted, so deeper fracturing, melting, and contraction occurred at an accelerating rate. By the end of the flood phase, the Pacific plate’s foundation had fractured in millions of places, and the magma generated along the deep sliding surfaces instantly contracted. Therefore, the Pacific plate, lacking support, rapidly subsided and sheared around its perimeter—now called the ring of fire. This shearing suddenly increased the upward pressure under the rising Atlantic floor, so the hydroplates began to accelerate away from the rising Mid-Atlantic Ridge. That also removed weight from above the Atlantic floor, so it rose even faster.
Because so much compressible magma was quickly produced under the Pacific plate, that plate subsided faster than the Atlantic floor rose. In hours, the downhill slope on which the hydroplates slid steepened, and the sheared Pacific basin, surrounded by the ring of fire, became so deep that it did not obstruct the hydroplates sliding away from the rising Mid-Atlantic Ridge.
After the flood, magma under the Pacific floor, but above the crossover depth, erupted onto the ocean floor. (To a much lesser extent, eruptions continue today, so in those places, ocean temperatures rise temporarily, a phenomenon called El Niņo.12) Magma below the crossover depth drains down into the outer core, so the outer core is slowly growing. Simultaneously, melting is shrinking the total volume below the crossover depth, so the crust is compressing like the wrinkling skin of a drying (shrinking) apple. Also, the continents, thickened during the compression event, are still sinking into and laterally displacing mantle material. Therefore, the entire mantle is being squeezed upward from below and downward from above. Because mantle volume is being lost primarily from the Pacific mantle by draining below the crossover depth and eruptions above the crossover depth, the mantle is shifting an inch or so a year, in general, toward the Pacific to replace that escaping volume. [See Figure 86 on page 157.] These movements and stresses produce earthquakes. Slowly shifting continents led to the mistaken belief that the entire solid mantle somehow circulates as if it were a liquid—and, over hundreds of millions of years, drifted continents over the face of the earth.
Since the flood, magma that spilled up onto the Pacific floor has raised sea level relative to the subsided Pacific plate that lies a few miles below the Pacific floor. This slow rise allowed today’s coral islands on top of tablemounts to grow upward—fast enough to maintain the sunlight they needed for optimal growth. The coral depth below one of these islands, Eniwetok Atoll, is 4,600 feet.19
Rapid Cooling. Some claim that if magma spilled out only about 5,000 years ago, heat would still be present. The lack of heat, they assert, shows that millions of years have elapsed. They have overlooked the contents of that magma: (a) crystals of unmelted minerals with high melting temperatures, (b) rock fragments, called xenoliths (ZEN-oh-liths), dislodged by the violent shearing and crushing, and (c) water absorbed by the rising magma as it passed up through what remained of the subterranean water chamber. (This is why volcanoes emit so much water vapor; typically 70% of all the gas released by volcanoes is water vapor.)20 Because water lowers magma’s melting temperature, the magma remained a liquid at temperatures below the rock’s normal melting temperature. The solid crystals and rock fragments absorbed heat from the magma, so it quickly cooled and solidified.
The Hydroplate Theory. [For a summary of the hydroplate theory, see pages 108–140.] At the end of the flood phase, crumbling, unsupportable walls and erosion from escaping high-velocity water had widened the globe-encircling rupture to an average of about 800 miles. Exposed at the bottom of this wide, water-filled gap was the subterranean chamber floor, about 10 miles below the earth’s surface. Before the rupture, the gigantic upward pressure directly under the floor balanced the weight of almost 10 miles of rock and 3/4 mile of water that pressed down on the floor. Afterward, with the overlying rock suddenly gone, only the strength of the upward-bulging chamber floor and 10 miles of water on top of it resisted this upward pressure. Consequently, as the rupture widened, the Mid-Oceanic Ridge suddenly buckled upward. [See pages 122–125.]
The continental-drift phase began with hydroplates sliding “downhill” on a layer of water, away from the rising Mid-Atlantic Ridge. This removed more weight from the rising portion of the subterranean chamber floor, causing it to rise even faster, and accelerating the hydroplates even more. As that part of the chamber floor rose to become the Atlantic floor, it stretched horizontally in all directions, just as a balloon stretches when its radius increases. This stretching produced cracks parallel and perpendicular to the Mid-Oceanic Ridge. The rising began in the Atlantic, so the Mid-Atlantic Ridge and its cracks are the most prominent of the oceanic ridge system.
Because deep voids could not open up in the compressed rock under the rising Atlantic floor, even deeper material was “sucked” upward. Within the inner earth, material shifted toward the rising Atlantic floor, forming a broader, but initially shallow, depression on the opposite side of the earth—the Pacific and Indian Oceans. Just as the Atlantic floor stretched horizontally as it rose, the western Pacific floor compressed horizontally as it subsided (sank). Both the rising of the Atlantic floor and the subsidence in the Pacific steepened the downhill slope beneath the sliding hydroplates.
The trench region of the western Pacific lies near the center of the combined Pacific and Indian Oceans. As material beneath the western Pacific was “sucked” down, it sheared and buckled downward in some places, forming trenches. The Atlantic Ocean (centered at 21.5°W longitude and 10°S latitude) is almost exactly opposite this trench region (centered at 159°E longitude and 10°N latitude). [See Figure 80 on page 145.]
A simple, classic experiment illustrates some aspects of this event.
A cup of water is poured into an empty 1-gallon can. The can is heated from below until steam flows out the opening in the top. The heat is turned off, and the cap is quickly screwed onto the top of the can, trapping hot steam in the metal can. As this steam cools, a partial vacuum forms inside the can. The can’s walls buckle inward, forming wrinkles in the metal—“miniature trenches.”
The upper 5 miles of the earth’s crust is hard and brittle. Below the top 5 miles, the large confining pressure will deform rock if pressure differences are great enough. Consequently, as the western Pacific floor sank, it sheared and buckled into “downward creases,” forming trenches. The hard crust and deformable mantle frequently produced deformations with an “arc and cusp” shape. The brittle crust cracked and slid in many places, especially along paths called Benioff zones.21
Figure 84: Trench Cross Section Based on Hydroplate Theory. Notice that the trench axis will generally not be a straight line. Sediments (green) hide the top of a fault plane that would otherwise rise up to a few hundred feet above the floor. Other sediments (not shown) and flood basalts (dark gray) cover most of the western Pacific floor. The three large black arrows show the direction of the rising Atlantic and the forces that downwarped the mantle and the Pacific plate. Earthquakes occur on the many faults produced, especially in Benioff zones and at low tides. Most volcanoes are not above Benioff zones, but are near a myriad of other faults near the center of the western Pacific, where downwarping and shearing were greatest.
Deformations inside the earth slid countless pieces of highly compressed rock over, along, and through each other. This faulting generated extreme friction—and, therefore, heat.
To appreciate the amount of heat generated, slide a brick one foot along a sidewalk. The brick and sidewalk will warm slightly. Sliding a brick an inch but with a mile of rock squarely on top would melt part of the brick and sidewalk. Earth’s radius is almost 4,000 miles. Place a few thousand of those miles of rock on top of the brick and slide it only one thousandth of an inch. The heat generated would melt the entire brick and much of the sidewalk below.
Small movements deep inside the solid earth melted huge volumes of minerals. This released the water locked within the crystalline structure of certain minerals.
Some magma (liquid rock) flowed upward onto the granite Pacific plate. Researchers have begun to detect this granite under the floors of the Pacific and Indian Oceans.22
Let’s suppose that the inner earth initially had a more uniform mixture of minerals throughout. Melting of minerals with lower melting temperatures would allow denser material to settle and lighter material to rise, a process called gravitational settling. This would generate much more heat and produce more faulting, melting, and gravitational settling. After many such cycles, the earth’s core would form with solid, denser minerals (containing iron and nickel) settling to form the inner core and the melt rising to form the liquid outer core. Shifting so much mass toward the center of the earth would increase the earth’s rotational speed. Today, the earth spins 365.256 times each year, but there are historical reasons for thinking a year once had 360 days.23 [For details and calculations, see “Melting the Inner Earth” on pages 446–449.]
We saw that the skater in Figure 81 spins faster as she draws her arms closer to her spin axis. Likewise, as denser minerals settled through the magma toward the center of the earth, the inner core spun faster than the outer earth. The inner core is still spinning faster (by about 0.4° per year),24 because the liquid outer core allows slippage.
In the mid-1980s, seismologists noticed that seismic waves pass through the inner core about 4 seconds faster when traveling along the axis of the magnetic poles.25 Other tests showed that this was because crystals in the inner core have a preferred orientation.26 That direction is slowly changing, so the inner core must be spinning relative to the rest of the earth. “The Origin of Earth’s Powerful Magnetic Field” explains how this alignment arose. Other evidence, explained in Endnote 18, supports these powerful movements inside the earth.
Gravity is the basic driving mechanism that formed trenches and slowly shifts the crust. Gravity always tries to make the earth more compact (or spherical).27 If you suddenly removed a bucket of water from a swimming pool (or even a 10-mile-thick layer of rock lying above what is now the Atlantic floor), gravity would tend to smooth out the irregularity. Because massive volumes of rock inside the earth do not flow as fast as water in a swimming pool, mass deficiencies, which we might think of as slight partial vacuums, still exist under trenches. Today, especially at low tide (when the water’s pressure on the ocean floor is a minimum), mantle material flows in very slightly under trenches to reduce these “partial vacuums.” This stretches the crust above, produces extensional earthquakes near trenches, shifts plates toward trenches, and makes the earth measurably rounder.28
Both the hydroplate theory and the plate tectonic theory are explained as their advocates would explain the theories. One should critically question every detail of both theories, and not accept either until all available evidence has been considered.
The Plate Tectonic Theory. The earth’s crust is broken into rigid plates, 30–60 miles thick, some with an area roughly the size of a continent. Some plates carry portions of oceans and continents. Plates move relative to each other over the earth’s surface, an inch or so per year.
Figure 85: Plate Tectonic Explanation for Trenches. Internal heat circulates the mantle, causing large plates to drift over the earth’s surface. Consequently, material rises at oceanic ridges, forcing the seafloor to spread, so plates must subduct at ocean trenches, allowing layered sediments, shown in yellow, to collect. According to plate tectonics, earthquakes occur where plates subduct (Benioff zones) and at other plate boundaries. [W. Brown: This theory says subducting plates also melt rock, and the resulting magma rises to form volcanoes. Actually, most volcanoes are not above Benioff zones. If this theory were correct, the yellow sediments would hide a cliff face that is at least 30 miles high and the trench axis should be a straight line.]
Heat is the basic driving mechanism that formed trenches and moves plates. Just as hot water circulates in a pan on a stove, hot rock circulates slowly inside the earth’s mantle. Radioactive decay warms some parts of the mantle more than others. The warmer rock expands, becomes less dense (more buoyant), and slowly rises, as a cork rises when submerged in water. Sometimes, plumes of hot rock rising from the outer core break through the earth’s crust as flood basalts. Conversely, relatively cold rock descends. Rising and descending rock inside the mantle forms circulation cells (convection cells) which drag plates forward. Currents within the mantle rise at oceanic ridges, create new crust, and produce seafloor spreading.
Because new crust forms at oceanic ridges, old crust must be consumed somewhere. This happens wherever two plates converge. The older plate is denser, because it had more time to cool. Therefore, it sinks below the younger plate and subducts into the mantle, forming a trench. A cold, sinking edge will pull the rest of the plate and enhance circulation in the mantle. Earthquakes occur under trenches when subducting plates slip along Benioff zones. At great depths, subducting plates melt, releasing magma, which migrates up to the earth’s surface to form volcanoes. Most of the ring of fire is produced by subducting plates. Of course, such slow processes require hundreds of millions of years to produce what we see today.