The Early Cretaceous tore continents apart and gave the world its first flowers
Between roughly 143.1 and 100.5 million years ago, the Atlantic unzipped, India drifted loose, and the largest volcanic outpouring Earth has ever known flooded the South Pacific floor. Amid that upheaval, flowering plants, modern birds and some of the oldest known mammals made their debut.
Around 120 million years ago, the Ontong Java–Manihiki–Hikurangi province erupted in the South Pacific, the biggest such lava province in the planet's history. Its Ontong Java Plateau alone now spans about 1,860,000 square kilometres. At about the same time the Kerguelen Plateau and Broken Ridge began forming in the Indian Ocean, and that activity later helped shove India northward. Earlier, starting 133 million years ago, the Parana–Etendeka eruptions spilled 1.5 million cubic kilometres of basalt and rhyolite over roughly a million years as the South Atlantic opened.
Such floods of lava may be tied to a drop in ocean oxygen, the early Aptian anoxic event, which drill cores from Svalbard date to 123.1 million years ago, give or take 0.3 million years. That date narrowed a long-running argument about where the Barremian stage ends and the Aptian begins.
The map changed dramatically. The Mid-Atlantic Ridge pushed north, prising Iberia away from Newfoundland; the opening Labrador Sea left Greenland on its own plate. The Falkland Plateau split from southern Africa at 132 million years ago, and by 110 million years ago South America and Africa had effectively parted. Rifting in the Indian Ocean separated India, Antarctica and Australia.
Life kept pace. Ceratopsians and spinosaurids rose among dinosaurs, and the first modern birds appeared. China's Yixian Formation holds Archaefructaceae, among the earliest flowering plant families at 124.6 million years, and Sinodelphys, a 125-million-year-old tree-climbing mammal closer to marsupials than placentals. The oldest known egg-laying mammal, Steropodon, lived in what is now Australia 105 million years ago.
Source: Early Cretaceous
