The E Horizon is best described as which of the following?

• A. Mineral horizon with loss of silicate clay, iron or aluminum
• B. Organic-rich surface layer
• C. Bedrock
• D. Soil with high calcium carbonate

Answer: (A)

The key idea is eluviation: an eluvial mineral horizon where water has washed out fine clay minerals, iron, and aluminum oxides. This leaching reduces the clay content and often lightens the color, creating a distinct layer that sits below the surface horizon and above where those materials have accumulated. The organic-rich surface layer would be the O horizon, bedrock is the R horizon, and a horizon with high calcium carbonate points to a calcic horizon. So the defining feature of the E horizon is the loss of silicate clay, iron, and aluminum through eluviation.