Have you ever visited a mud volcano?
Mud volcano isn't a real volcano. It doesn't erupt lava. It erupts mud instead. Mud contains water. So, here comes a question, "where is the water from?"
This is a very simple question. You might have an answer already. You may remember the Chinese poem. It says, "Don't you see? The water of the Yellow river comes from the sky." Analogizing to Mud Volcano, you may say, "Don't you see? The water of the Mud Volcano is from the sky." As the rainwater permeates through earth and become groundwater, it dissolves the mudstone into mud. This is what geographers say. Do you agree with this viewpoint?
Logically, there are two possible answers to this question. One is the above. Besides, we have an alternative choice. That is geologists' assertion. There is a debate between geographers and geologists. Most geologists think that the water comes from mudstone strata themselves. Just like lemon juice comes from lemon itself.
It may be unthinkable, but it is true.
There is mud reservoir underground. And the chamber is filled with over-pressurized gas. Because of the pressure, mud is forced to escape from the reservoir through the fractures. Therefore the fractures are full of gas and mud, so that groundwater can not flow into the reservoir through them. And mudstone is waterproof. It is impossible that the water comes from the outside of mudstone. However, where is the original water from?
For answering this question, we have to go back to the era when the mudstone formed. What happened then? We don't known. But, "the present is a key to the past". If we know what is happening on deep seafloor now, we may answer the question.
Geologists have found a huge amount of gas hydrate in the mud sediments on deep seafloor recently. Gas hydrate is a kind of solid ice-like compound. It is combined with natural gas and water at high pressure and low temperature. It reminds us that the mudstone strata, formed from mud sediments on deep seafloor, also contain a huge amount of gas hydrate. As the strata crack, the pressure releases and gas hydrates decompose into water and gas. That is where the water from. The water is from the inside of mudstone strata. And the mud contains ancient sea water.
Have you changed your mind? Or you may ask, is there any evidence?
Of course! The Mud is salty. If you like to taste it, you will find that.
By the way, you had better recognize this viewpoint, because gas hydrates may become the most important source of energy in the coming future.
(Alan's C9 speech, 2007/4/4)