Post by Admin on Aug 26, 2023 5:57:39 GMT -7
On Earth we have access to two kinds of rocks.
Crustal surface rocks and mantle rocks.
Crustal surface rocks and mantle rocks.
Surface rocks are more complex than mantle rocks because for 4.5 billion years it has been receiving over 100 tons of space dust every 24 hours! That is not counting meteorites, asteroids, and comets.
Thee are FOUR (NOT THREE!) ROCK DIVISIONS.
IGNEOUS, METAMORPHIC, SEDIMENTARY, AND IMPACT
IGNEOUS, METAMORPHIC, SEDIMENTARY, AND IMPACT
They are all interchangeable. Igneous rocks cool and are worn into sedimentary. Sedimentary rocks are subducted and become igneous. Heat and pressure convert them into metamorphic. Limestone is converted into marble, sandstone into quartzite. Asteroids and planets are blasted apart and they all become impact rocks.
Now about COMETS . . .
There are two kinds of comets. Those that formed in our molecular cloud and are composed of the same elements in roughly the same amounts as earth, and those from outside.
It is possible that we have mostly encountered the first kind, BUT we have obviously encountered the second kind.
Copper was not indigenous to our molecular cloud, but the ancient copper areas of Canada and Russia verify huge ancient impacts.
