Why does this Iranian island resemble Mars after rainfall?

On an island off the coast of Iran, the soil contains a high concentration of iron oxide. This compound is responsible for the reddish hue seen on Mars and the rusting of metals on Earth. When it rains, the water mixes with the iron oxide in the soil, creating a striking effect.

As a result, the runoff from the rain flows into the ocean, staining the water a deep blood-red color. This natural phenomenon is different from 'blood rain,' which occurs when raindrops come into contact with dust or dirt suspended high in the atmosphere, giving the rain an eerie reddish tint.

Sources:

• Why this Iranian island looks like Mars after it rains