The formation of rivers is a long and gradual process, and the formation of rivers is usually achieved through the following processes:1. Rainfall: Heavy rain or snowmelt water will accumulate on mountains or plateaus.

These creeks will gradually join to form larger rivers.

2. Weakening rocks: The currents and flowing rock fragments in the river will constantly rub and erode the rock surface, gradually forming river beds and banks.

3. Further erosion: As the river deepens, it erodes the underlying rock and soil, creating canyons and ravines.

4. Accumulation of sediment: The water flow in the river carries rock fragments, sediment, and other sedimentary materials. As the water flow slows down, these sedimentary materials will be deposited on the bottom of the river and gradually form a river bed.

5. River expansion: Over time, rivers expand, forming valleys and plains. In river valleys and plains, the flow of river water slows down and sediment is deposited more quickly, forming river beds and banks.

The geological function of the river refers to the influence of the river on the surrounding environment in terms of geology. Here are some examples of the geological role of rivers:

Erosion: The continuous friction between the current of the river and the rock fragments under the water, erodes the riverbed and banks, further erodes the rock surface, and forms canyons and deep valleys.

Sedimentation: The water flow in the river carries a large amount of sediment, including rock fragments, sediment, etc. As the water flow slows down, these sedimentary materials are deposited on the bottom and banks of the river, forming the riverbed and plain of the river.

Stratigenesis: Sedimentation by rivers geologically contributes to the formation of fluvial sedimentary rocks. For example, gravel, sand, and silt deposited in rivers can form rocks such as sandstone, mudstone, and shale under pressure and time.

Rivers change landforms: The geological effects of rivers can change the surrounding landforms, for example, the erosion of rivers can form deep valleys and canyons, and the deposition of rivers can form plains and hills.

Formation of mineral resources: Sediments in rivers can deposit some minerals, such as metal minerals such as gold, silver, and tin, as well as fossil fuels such as coal and oil. Therefore, rivers are also important geological resources for prospecting and mining mineral resources.

Here are some famous rivers in the world:

1. Nile River: Located in Africa, it is the longest river in the world, with a total length of about 6,695 kilometers.

2. Amazon River: Located in South America, it is the largest river in the world, flowing through Brazil, Peru, and other countries.

3. Yangtze River: Located in China, it is the longest river in Asia with a total length of about 6,380 kilometers.

4. Yellow River: Also located in China, it is the second longest river in China and is named for its yellow color due to the mixed sand and soil.

5. Little Fuji River: Located between Shikoku Island and Honshu Island in Japan, it is a strait with very strong tidal surges and one of the world's famous tidal eddies.

6. Yucatan Peninsula Underground River: Located in Yucatan Peninsula, Mexico, it is one of the longest underground rivers in the world, with a total length of about 95 kilometers.

7. Ganges: Located in India and Bangladesh, with a total length of 2,510 kilometers.

8. Danube: Located in Europe, it is the second longest river in Europe, flowing through 10 countries, with a total length of about 2,860 kilometers.

9. Amamo River: Located in Central Asia, it flows through Tajikistan, Uzbekistan, Turkmenistan, and other countries, with a total length of about 2,400 kilometers.