The+Geologist+Speaks+by+Alejandra

=The Geologist Speaks= An account of a class visited by a geologist from MIT, Mr. Blackburn, and what can be learned from what was said.

Hello people all over the world! You are reading this Wiki about geology and geologists. I am Alejandra, a 7th grader from the [|Amigos School] in Cambridge Massachusetts. My school is one of the few bilingual (Spanish/English immersion) schools in North America. I consider myself completely fluent in both languages. However this Wiki is not written to educate you on my school, this Wiki’s purpose is to educate you about the world around us, the rocks around us. Now that I have introduced my cause and myself; we can move along.

On Thursday the 20th, December 2007, Mr. Blackburn, a geologist from MIT (Massachusetts Institute of Technology) visited both 7th grade classes of the Amigos School. Mr. Blackburn is in the department of [|Eaps Education Geology and Geochemistry] studying plate tectonics. This department is interested in things such as interactions between the crust and mantle. He told Ms. Ferhani’s science class about rocks. Rocks, how ever unimportant they may seem, are very important. Rocks make up plate tectonics; landmasses carrying our continents and oceans, fitting together like puzzle pieces and moving. Yes, we as a world are always moving. Our planet itself is always revolving around the sun but plate tectonics are also moving; smashing into each other, moving away. This is all happening but why can’t we see it? Tectonic plates move about a centimeter a year.

There are two types of tectonic plates: continental and oceanic. Continental plates are made of granite and carry continents/ land. Oceanic plates are made of basalt and carry oceans/ water. Plates are not necessarily split up by continental or oceanic, they can be both just different parts of the plate tectonics are different types. Now that you know some of the background information here comes the really cool stuff.

A theory geologists such as Mr. Blackburn have discovered is that all planets in our solar system was created all at the same time, 4.6 billion years ago (bya). A question asked is then why is the oldest rock on Earth, found on a mountain in Canada (but bits have been taken to places such as MIT), only 4.03myo. This question can be answered in two words: convection currents. Earth is the only planet with convection currents, a gravitational pull which pulls rocks back to the core where they are returned to there original state; magma a.k.a. lava before being released from a volcano. Since rocks end up as magma after a while, once they are returned to the crust (the layer of Earth we live on) they have been melted and changed so much it is not possible to date them anymore therefore the absolute oldest rock on Earth could be any rock of today or even not of today, maybe it’s magma right now!

The only other object in the solar system that is not the same age as the other objects in the solar system is the moon.. Earth’s moon used to be part of Earth itself. In pictures of the moon you can see its craters with huge indents of basalt. When I heard they were made of basalt I didn’t understand, I thought basalt was oceanic plates and there is no water on the moon. Mr. Blackburn told us that there was a lot of basalt in space; most craters are composed of basalt. Basalt is heavier then granite. Since the plates float on the asthenosphere (a layer of Earth) basalt sinks into this liquid layer due to it’s wait making a dent that water fills. Have you ever noticed that when you are trying to get onto a float in the pool as you sit your wait creates a dent and the water comes in when you were hoping to be nice and dry? It’s the same concept. For the moon and other planets it’s practically the same thing except the basalt does not sink into a liquid layer because other planets do not have layers.

Craters are formed by the impact of the collision of an asteroid and an object in our solar system. Most astronomers believe that asteroids are pieces of a blown up planet that still orbit the sun but sometimes are pushed out of orbit by larger things and gravity pulls them to hit other planets. Since asteroids are not a planet anymore they orbit differently then a planet would, they form what is called the Asteroid Belt, a ring of orbiting asteroids. Since basalt it heavy and hitting the planet/moon very very fast it makes a dent which is not filled by water because there is no water on other planets/moons.

Did you know!!? Only Earth has continental Crust.

In conclusion it was amazing to hear all the things I heard. It was a moment of understanding “Ohhhhhh”’s. I want to say thank you to Mr. Blackburn for coming to my class and talking to us about this and I want to say thank you to you, all my readers Bye!