Mesozoic that would move into their current positions during the next era. The climate of the Mesozoic was varied, alternating between warming and cooling periods. Overall, however, the Earth was hotter than it is today. Dinosaurs appeared in the Late Triassic and became the dominant terrestrial vertebrates early in the Jurassic, occupying this position for about 135 million years until their demise at the end of the Cretaceous. Birds first appeared in the Jurassic, having evolved from a branch of theropod dinosaurs. The first mammals also appeared during the Mesozoic, but would remain small—less than 15 kg (33 lb)—until the Cenozoic.
Carabobo Field attributed to the formation of the field is when North America separated from Gondwanaland in the Late Triassic/Early Jurassic (~200 million years ago). The rifting in this period is represented by Late Jurassic basalts deposited in the Espino graben. This event led to the northern passive margin of South America. During the Cretaceous Period (~150 million years ago), the passive margin began to subside from organic rich sediments being deposited. This deposition includes the Querecual and San Antonio formations that would become source rocks for the Orinoco Oil Belt. The next tectonic event is referred to as a progressive collision