The Cocos plate was created about 23 million years ago when a larger plate broke into two pieces. The other piece became the Nazca plate. The Cocos plate also broke into two pieces, creating the small Rivera plate.
The Cocos plate touches several different plates. To the northeast it touches the North American plate and the Caribbean plate. To the west it touches the Pacific plate and to the south the Nazca plate.
This complicated set of little plates is caused by what geologists call the Cocos-Nazca spreading system. The leading edge is subducting (going under existing plates). This causes the Central American Volcanic Arc.
Cocos plate Facts for Kids. Kiddle Encyclopedia.