Geology
The Geology of the Planet Demeter
The Formation And Geology
As the rocky planets and satellites reached the last stages of their formation
most of the heavier elements such as iron and uranium that had been near the
surface began to sink down towards the core while lighter elements began to
float up to the surface. Gravity caused further collapse and as the
molecules of the planet/satellite were squeezed closer and closer together
they began to heat up more and more. The radioactive decay of heavy
elements and the descent of iron and uranium into the core created additional heat which would keep the interiors of
planet/satellite molten for the billions of years following formation.
As time passed the planets/satellites stopped collapsing and slowly began to cool. A thin wrinkled crust with the texture of partially melted wax formed over their surfaces and volcanoes developed around thin spots in this new crust. The core differentiated which means that it separated in most cases into a solid inner core and a spinning liquid outer core creating a magnetic field and belts of radiation which helped to block the solar wind and harmful incoming radiation. The age of bombardment began as millions of asteroids and comets collided with the new planet/satellite adding to its mass and supplying minerals and volatiles. Volcanoes and fissures spewed out lava, water vapor, hydrogen chloride, carbon monoxide, carbon dioxide and nitrogen which over time combined into methane, ammonia and hydrogen chloride. These new gases mixed with the trace amounts of air left over from the original atmosphere creating a nutrient rich soup. Because of the large amount of volcanic activity and bombardment from space the atmospheres of early planets/satellite thickened quickly, soon becoming very large. The early atmosphere trapped heat easily because of the high concentration of greenhouse gasses and its thickness so the temperature soon increased significantly along with the albedo.
Hundreds of millions of years passed by and as they did the planet/satellite and its atmosphere cooled further. The crust solidified and thickened as radioactive decay slowed down and volcanic activity became more limited. The atmosphere also showed development at this time by becoming much thinner and cooler. Reducing allowed air molecules to escape into space and because the early parent star was much smaller and dimmer at the beginning of its life on the main sequence than at a later date the planets/satellites radiated more energy than they received causing them to gradually cool. Eventually the critical point was reached as to where liquid could exist and once this occurred huge quantities of it rained down from the sky for millions of years pooling in the low areas of the crust on some worlds. The new crust began to erode as the liquid flowed over the new rock and carried it downstream to the developing seas. Large bodies of water soon became salty as salt from the rock was washed into them along with clay and mud over hundreds of millions of years. What we know as the water cycle was taking place even though the surface liquid was not always water. Occasionally large lakes and even miniature seas would collect above sea level held back only by large dams of rock. The water would erode at the rock until the dam broke and then the water would rush downhill carving huge canyons in a matter of days.
Erosion also occurred from other physical and chemical weathering
processes. During the warmer part of the planet/satellites year some of the water
would seep into the rocks of the crust. As the planet moved into the
cooler part of its year and the temperature dropped the
water froze and then thawed froze and thawed until the rock began to break and
crumble. Water and wind passed over the rock smoothing the sharp edges. The rock
crumbled and broke down into smaller and smaller pieces until it was washed or
blown away. Chemicals also helped to break down the
rock dissolving it into gravel clay and mud. More lava erupted onto the land and the process began again. This happened
over and over and over for hundreds of millions of years gradually shaping the
planet/satellites surface.
Soon after the crust formed and thickened it began to crack and fracture. It broke
into several large pieces which slowly slid over the hotter rock beneath them. This is called tectonic activity
and it is only possible when a liquid is present in large amounts to ease subduction in trenches. The rock beneath the plates was thick and
gooey like molasses and so the plates moved very slowly on top of it at a rate
of about 3 centimeters per year. Sometimes two or more plates would
collide often resulting in the heavier plate sinking beneath the lighter plate
producing large mountains volcanoes and trenches. Two plates of equal weight would collide and form
mountain ranges. When the plates moved away from each other they would either
form a rift valley or a ridge where lava would just seep up and fill in the gap.
Eventually tectonic activity in all but the most massive planets/satellites would begin to slow and after many billions of years the continents would become locked in place forever due to the loss of internal heat. As more time passed and the parent star shifted out of the main sequence the planet/satellite could actually be destroyed if the star entered a red giant phase but if it wasn't destroyed it would eventually cool down so completely that even its fiery core would become cold and hard, a burnt out ember.