ProterozoicThe Proterozoic (ˌproʊtərəˈzoʊɪk,prɒt-,-əroʊ-,-trə-,-troʊ-) is the third of the four geologic eons of Earth's history, spanning the time interval from 2500 to 538.8 Mya, the longest eon of the Earth's geologic time scale. It is preceded by the Archean and followed by the Phanerozoic, and is the most recent part of the Precambrian "supereon". The Proterozoic is subdivided into three geologic eras (from oldest to youngest): the Paleoproterozoic, Mesoproterozoic and Neoproterozoic.
Plate tectonicsPlate tectonics (from the tectonicus, from the τεκτονικός) is the scientific theory that Earth's lithosphere comprises a number of large tectonic plates which have been slowly moving since about 3.4 billion years ago. The model builds on the concept of continental drift, an idea developed during the first decades of the 20th century. Plate tectonics came to be accepted by geoscientists after seafloor spreading was validated in the mid-to-late 1960s.
CenozoicThe Cenozoic (ˌsiːnəˈzoʊ.ɪk,_ˌsɛn- ; new life) is Earth's current geological era, representing the last 66 million years of Earth's history. It is characterised by the dominance of mammals, birds, conifers and flowering plants, a cooling and drying climate, and the current configuration of continents. It is the latest of three geological eras since complex life evolved, preceded by the Mesozoic and Paleozoic.
