The Galápagos hotspot is probably responsible for the main plume-related magmatic event 90 Ma, whilst the 76 Ma and 55 Ma event are related to lithospheric thinning in the Central Caribbean.
The Galápagos hotspot is probably the main trigger for the significant volcanic activity 90 million years ago. In contrast, the 76 million-year-old and 55-million-year-old events are more closely related to the weakening of the Earth's crust in the Central Caribbean region.