The late Cenomanian represents the highest
mean sea level observed in the
Phanerozoic eon, the past 600 million years (about 150 meters above present-day sea levels). A corollary is that the highlands were at all time lows, so the landscape on Earth was one of warm broad shallow seas inundating low-lying land areas on the precursors to today's continents. What few lands rose above the waves were made of old mountains and hills, upland
plateaus, all much weathered.
Tectonic mountain building was minimal and most continents were isolated by large stretches of water. Without highlands to break winds, the climate would have been windy and waves large, adding to the weathering and fast rate of sediment deposition. The Early Cenomanian was extremely hot, with mid-latitude sea surface temperatures (SSTs) estimated at >31°C and water temperatures in the upper bathyal depths estimated at >17 °C. During the Cenomanian, Labrador's mean annual temperature (MAT) was around 15.1 ± 2.1°C, one of the coldest in North America at this time. A pan-African rainforest existed.
Egypt was warm and humid, though occasionally saw intervals of relatively dry conditions. == References ==