The Earth’s Crust and the Geologic Column
It ranges from 5 miles in the depth of the ocean to about 15 miles on our mountains. So the average is about ten miles thick.
The thickest part of the earth's crust is under mountains. Whenever there is a volcanic eruption, more material is poured out on the earth's surface from under the crust, so in that sense yes, the earth's crust is increasing slowly.
Drillers have gone down about eight miles. They wanted to go down further, but it got so hot (about 356 degrees Fahrenheit) the drill bit wouldn’t work.
In our history, deeper means earlier. Earlier in our history we had different processes at work and different chemicals were bring brought up to the surface. So we would expect to find different types of things in the rocks as we dig deeper.
Water probably does most of it. Strata are formed underwater by water washing material off the land; by tsunami action; underwater earthquakes which bring material off the continental shelf; and turbidity current flows, which are massive flows of water down submarine canyons.
On land strata can be formed by windstorms, volcanoes, rock and mudslides, floods, earthquakes, and even meteorite impacts. We can see ash layers from volcanic activity and we can see where erosion of mountainsides has produced layers where the material ended up. We can see some layers of sand blown in by winds, and these layers may well be covered by layers brought in by water later. A large meteorite impact can ‘splash’ material around it, causing a layer to form. There are a lot of causes, but, yes, a lot of what we see has been laid down by water at various times.
A lot of strata did form under water. But we can tell which strata formed under air by the particles in the layers; by the slopes, or angles of the sides; the presence of parts of land-dwelling plants and animals; and the tracks of some of those animals. In addition, lava strata underwater form in pillow-like shapes; this does not happen under air.
The geologic column is simply a term used to explain the finding that the earth’s crust has been formed in layers and is not all the same thing all the way through. There is no need to prove or disprove it; it is simply something that is.
We are all in agreement about the basic eras represented in the geologic record. The layers are there. They are actual, physical data. It is what they represent and the time element involved that are matters of disagreement.
These are two of the areas of the world where the complete geologic column can be found.
Not at all. The four major eras (Archaeozoic/Precambrian, Paleozoic, Mesozoic and Cenozoic) exist all over the earth in the same order. The fact that some of the tiny subdivisions exist in some areas and not in others is simply the result of different sorts of layering activity at different times as well as earth movements and erosion.
The whole thing? It took about 3200 years.
Many. It depends on the types of rocks, on volcanic activity mixed with these rocks, on earthquakes that move the crust around, on floods that carry sediments to become layers... it depends on all kinds of things. It is for this reason some places have more strata than others. They have had more geologic activity in their local area to result in some extra strata being formed.
A flood can layer things in minutes. Breezes blowing dust around could take thousands of years for the same amount of deposition.
Geologists have given even the skinniest layers their own names.
You mean the letters ‘zoic’? That is because the words are taken from the Greek. The ‘zoic’ is from the Greek word for ‘life,’ so “Archaeozoic” means “ancient life;” “Paleozoic” means “early life;” “Mesozoic” means “middle life” and “Cenozoic” means “recent life.”
The three major catastrophes killed enormous amounts of life on earth, changing the face of the earth and the basic environment in many areas. They were caused by a combination of impact events and the heating of the earth’s interior by radio decay.
There are a number of places where earth movements have broken the crust and tilted part of it up a good distance. Then we can see the layers in the crust and how thick they are.
We can also see a lot of the layers where canyons have been carved.
When we drill down for oil, we also pass through a lot of the layers and we can see how thick they are that way.
Hold up your hand. You have four fingers. But there are three spaces between the fingers to separate them. There are four major eras and there are three catastrophes separating them.
Yes, although it is often referred to as the Precambrian.
The Archaeozoic, or Precambrian, Era is that time before Noah’s Flood. Yes, people were alive on earth then. They are called the “antediluvians.” “Ante” means “before” (don’t get it confused with “anti” which means “against”) and the “diluvian” refers to the Deluge -- the Flood.
That’s a good question. Yes, it is.
Originally the crust was cool because of the way the earth’s material were layered, with the radioactive elements, which provide so much heat, in the core. This radioactive heating is still going on in the core, which we can see from volcanic explosions and geysers, but it is not enough to endanger us by actually heating the crust.
No. It is a very beautiful canyon with different colors in it. An extraordinarily beautiful series of photos of it can be found here.
The Grand Canyon is 277 miles (446 km) long, up to 18 miles (29 km) wide and attains a depth of over a mile (6,000 feet or 1,800 meters).
The layers -- the strata -- built up over several hundred years. But the canyon itself was ripped out very quickly by the bursting of waters from a great inland sea. All that is left of that sea now is the Great Salt Lake.
There are two possibilities regarding how Grand Canyon was formed. First of all, it was not formed slowly by the Colorado River. That is all that is left now of a local catastrophe. The first possibility is that the Canyon was formed by a sudden flood of water rushing down after a natural dam broke in the inland sea.
However, there is another possibility. We are learning more about electric discharges now and some of the evidence is starting to accumulate indicating that many of our river and canyon systems were actually carved by giant electric discharges that happened long ago between planets or comets and planets where the electric charges were so different that it caused giant lightning bolts. Sometimes these electric discharges would continue carving out land (we see where this has happened on other planets) for a pretty long distance before they die down. What is left is where the river flows.
Grand Canyon actually shows a shape that could easily indicate it is the result of a large electric discharge four or five thousand years ago.
No, the debris layer has been eroded away and, where it may still lie buried, has probably been changed (metamorphized) by the heated intrusions of the Zoroaster Granite. We see the results of this heating in the Vishnu Schist.
The evidence is most certainly NOT simply written records, although they have helped. The evidence is in the layers of rocks themselves and in the fossils. We can see where great catastrophes wiped out millions of plants and animals. We can see where rock types change abruptly and we can see where bits of evidence like shocked quartzite and iridium layers indicate a violent and large asteroid hit. Where the earth's crust has been tilted up, we can see the arrangement and depth of the layers and work with that knowledge as well.
They all move, but in different directions.
Old mountains have been worn away by winds and rains and such. Younger mountains are still sharp and rugged.
The Appalachians, below, are a very good example of very old mountains:
The Rockies are very good examples of young mountains:
In the above picture you can see where some fan-shaped erosions are at the base of the mountains. Given enough time, these mountains, too, would erode into much more gentle shapes.
It took awhile for the whole thing to be completely agreed upon, but the data eventually convinced them. It took a few years, but it is generally accepted now.