Soil particles vary greatly in size, and soil scientists classify soil particles into sand, silt, and clay. Starting with the finest, clay particles are smaller than 0.002 mm in diameter. Some clay particles are so small that ordinary microscopes do not show them. Silt particles are from 0.002 to 0.05 mm in diameter.
Answer
La corteza terrestre temprana apareció hace aproximadamente 4.500 millones de años, después de las últimas etapas de acreción planetaria.
