Earth crust in numbers
I can consider myself as a humanist as much as I like when, for example, I write an article or read a good book, but I come to true harmony with the outside world only when I see an even column of numbers. Probably, an accountant died in me :). Therefore, today, in order to find peace of mind, I decided to share with you, my friends, the numbers I haverelative to the earth's crust.
So, to hell with the lyrics, only numbers, numbers and numbers go on!
To the share of the earth's crustaccounts for 1% of the total mass of the Earth.
Hard bark thicknessvery small: from 10 km under the oceans to 80 km under the mountain ranges on the continents.
Bottom linecrust passes along the border (surface) Mohorovichich - the zone in which there is a sharp jump in the velocity of seismic waves. Longitudinal from 6.7–7.6 km / s to 7.9–8.2 km / s., And transverse - from 3.6–4.2 km / s to 4.4–4.7 km / s .
Currently on the surface of the earthallocate 6 large arraysthe crust of the continent, protruding above the level of the World Ocean: Eurasia (55 million km2), Africa (30 million km2), North America (24 million km2), South America (18 million km2), Antarctica (14 million km2) and Australia (8.5 millionkm2).
Approximately 75% of the continental surfacecovered with sedimentary rocks, although these rocks make up about 5% of the earth's crust.
Averagechemical compositionlithosphere: oxygen - 49.4%, silicon - 25.8%, aluminum - 7.5%, iron - 4.7%, - carbon - 0.087%.
Composition of the continental crustsomewhat different: oxygen - 45.2%; silicon - 27.2%; aluminum - 8.0%; iron - 5.6%; calcium - 5.1%; magnesium - 2.8%; sodium - 2.3%; potassium - 1.7%; titanium - 0.9%; the remaining elements are about 1%.
Average densitycrust - 2.80 g / cm3.
Agemost of the ocean floor is less than 100 million years.
Most ancient oceanic crustIt is located in the western part of the Pacific Ocean, and its age is approximately 200 million years. For comparison, the age of the oldest minerals found on land reaches about 3 billion years.
Earth's center of masspresumably at a speed of 6.47 cm per century.
Most of the earth’s surface, about 90%, is covered14 major lithospheric plates.
Separateparts (blocks) of the lithosphere are shiftedindependently from each other over millions of years for hundreds and thousands of kilometers.
Lithospheric blocksin the diameter range are 1–10 000 km, and their thickness varies from 60 to 100 km.
On the lowering siteslithospheric plates are immersed in the mantleto a depth of 660 km.
Russia is locatedon four lithospheric plates.
The largest continental riftmore than 4000 km long and 80–120 km wide is in Africa.
For todaytotal cultivated landmakes up 13.31% of the land surface, of which only 4.71% are constantly engaged in agricultural crops.
Approximately 40% of Earth’s land today is usedfor arable land and pasturesIt is approximately 1.3 · 107 km² of arable land and 3.4 · 107 km² of pasture.