Weathering is the alteration of rock materials during exposure to air, moisture and organic matter. Variations in temperature and moisture are the primary elements of weather and weathering because they enhance chemical action. Granite is a familiar igneous rock and one source of sediment. The carbon dioxide is derived from the air and from decaying plants as the rain water percolates through the regolith. Kaolinite is a common constituent of clay, which is a large component of the regolith.
Potassium carbonate is a valuable nutrient for plants.
When all of the above minerals have been 'liberated' from the crystalline rock where they were formed they become part of the soils above the near-surface rock or are transported away and so become sediment and eventually perhaps sedimentary rocks. The surface of the earth slopes away from the equator so that the sun's rays hit it at a more oblique angle in the higher latitudes. More of the energy of the sun is absorbed before it hits the surface in the high latitudes causing less of it to actually strike the surface. Evidence of mechanical weathering preserved in the rock record helps to reconstruct paleotemperature. I.e., did temperature drop below freezing at a given location during a particular period in the geologic past.