The Amazon Jungle will have the fastest rate of weathering by far compared to the other suggested locations. The reason for that is that the weathering is the fastest at places where there's high temperatures, high precipitation, high humidity, and lot of vegetation. The Amazon Jungle has all of this characteristics. The high temperatures, rainfall, humidity, and vegetation, combined will contribute to mechanical and chemical weathering, that will take place constantly throughout the year, thus the rocks, or any other disposable material will not last for a long period of time in those circumstances.
