The simlarities between oceanic and continental crust are: 1. I dont know 2. I need help, someone that knows the correct answer please help me asap? This is my exam, but the information is not in my worksheet or either in my textbook
That depend on your religion. Some religions believe that people were. But if you go for evolution, then its single celled organisms.
asthenosphere.
The continental shelves were formed millions of years ago, when most of the land on the Earth was compacted into one huge landmass. After some time, this landmass began to break into smaller pieces, which became the continental shelves. Then they drifted farther and farther apart and appear where they are today.
A big rock from space could split the crust, or at least punch a hole in it. (And this has happened! And on several occasions.) We've had some really, really big hits, including one that is thought to have resulted in the capture and formation of the moon. A hit that massive didn't simply split the crust, but nearly ripped the earth apart. There is also the action of tectonic plates, as the plates respond to gigantic pressures from below. The actions of the tectonic plates had a hand shaping life on earth, and they continue to affect us today. I very big ways, too. Earthquakes arise when plates shift, as you know, but the divergent rifts on some plate boundaries could actually be considered a "functioning split" because the plates are continuing to move apart, continuing to split. Remember that the crust of the earth is an evolving megastructure. The massive dynamics that shaped it in the past continue to shape it now, even though billions of years of have passed since the crust formed.
You would find the oldest crust on Earth in certain parts of continental areas, such as the Canadian Shield or parts of Western Australia. These areas contain rocks that are over 3 billion years old, making them some of the oldest crust on the planet.
Short Answer: The Earth has two types of crust, continental crust and oceanic crust. Basaltic rocks are the main component of oceanic crust. Continental crust consists mainly of lower density granitic rocks. The Better Answer: Tectonic plates and the Earth's crust are not the same thing. Tectonic plates are made of the Earth's crust, plus the upper layers of the Earth's mantle. Together the crust and the more solid upper mantle form the lithosphere. The crust itself is relatively thin, varying from a few kilometers thick to nearly a hundred kilometers. With the material of the mantle, the tectonic plates are 50 to 200 kilometers thick. Some plates are entirely continental and some are entirely oceanic and some are combined. Continental crust and oceanic crust are different in make up and properties. The continental crust has a density of about 2.7 g/cm3 and is mostly granitic, made of silicate materials with more aluminum and less iron and magnesium. Continental crust is generally thicker, in the range of 25 to 70 kilometers. Oceanic crust is more dense (density of about 2.9 g/cm3) and the average oceanic thickness is in the range of 7-10 kilometers. Oceanic crust is primarily basalt, composed of silicate material which is rich in iron and magnesium. Though only 40% of the Earth's surface is continental crust, there is more of it because it is thicker. Continental crust is about 70% of the volume of Earth's crust. Both types of crusts are less dense than the material of the Earth's mantle (density of about 3.3 g/cm3), so the "float" on the mantle.
Tectonic plates consist of both continental and oceanic crust. The Earth's lithosphere is divided into several large and small plates that constantly move and interact with each other. Some plates are predominantly made up of continental crust, while others are mostly composed of oceanic crust.
Because the oldest parts reach the continental crust and then the ocean floor sinks beneath the continental crust, into the mantle.
The crust alone contains millions of different layers of sedimentary rock. For the layers of the Earth, some of which are rock and some of which are not, see the related link below.
The Moon's crust is generally thinner than Earth's crust. The Moon's crust is estimated to be roughly 30 to 40 kilometers thick, while Earth's crust is on average about 40 kilometers thick but can be much thicker in some areas like continental crust.
Continental crust is the thicker, less dense outer layer of Earth's lithosphere that makes up the continents. It is primarily composed of granitic rocks, such as granite and granodiorite, and is less dense than the oceanic crust, which is mainly basaltic in composition. Continental crust is relatively older than oceanic crust and can be several billion years old in some areas.
The thin, solid, outermost layer of the Earth is officially known as the crust.
Some geologists believe there are no tectonic plates composed solely of continental crust, as plates typically consist of both continental and oceanic crust. The concept of a plate composed entirely of continental crust is not widely accepted in the field of plate tectonics.
Subduction occurs on continental boundaries because oceanic sub floor is denser and heavier than the lighter more buoyant crust. The oceanic crust slides under the continental crust areas usually on a plate boundary. This is in a recycle style mode that constantly is remaking the ocean floor. The oldest rocks on the ocean bottom are a drop in the geologic time bucket, compared to the rock ages on land.
The continental crust is primarily composed of igneous, sedimentary, and metamorphic rocks. Igneous rocks do make up a significant portion of the continental crust, especially in the form of granite and basalt.
Of course it's continental crust! If it were made of oceanic crust, it would be underwater or some large island starting at the bottom of the ocean floor!