When materials like rocks and soil on the Earth's surface wear down to sand and gravel or move from one location to another, erosion is the main culprit. ... But the most powerful force behind erosion is gravity. Gravity causes chunks of rock to fall from mountains and pulls glaciers downhill, cutting through solid stone.
i do not know if this will help you because there is not a lot a lot of research, specifically explaining why gravity causes erosion.
good luck!