noun. the solid part of the earth consisting of the crust and outer mantle.
1. Adverb This versatile and abundant element cycles regularly through the Earth's atmosphere, hydrosphere, geosphere and biosphere, which essentially comprise a carbon reservoirs list. 2. Noun, singular or mass Trying to determine where the carbon cycle begins is a bit like trying to determine which came first, the chicken or the egg, but let's begin with the geosphere.