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Aptian extinction: 117 Ma: Unknown, but may be due to volcanism of the Rajmahal Traps [15] Jurassic: End-Jurassic (Tithonian) 145 Ma: No longer regarded as a major extinction but rather a series of lesser events due to bolide impacts, eruptions of flood basalts, climate change and disruptions to oceanic systems [16] Pliensbachian-Toarcian ...
A growing number of scientists believe a sixth mass extinction event of a magnitude equal to the prior five has been unfolding for the past 10,000 years as humans have made their mark around the ...
The Late Ordovician mass extinction is traditionally considered to occur in two distinct pulses. [10] The first pulse (interval), known as LOMEI-1, [11] began at the boundary between the Katian and Hirnantian stages of the Late Ordovician epoch.
An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp fall in the diversity and abundance of multicellular organisms .
The middle Cambrian to early Ordovician is characterized by persistent elevated extinction rates that are thought to have been maintained by anoxic conditions. [ 4 ] A decrease in the anoxic conditions of the Cambrian, and an increase in euxinic conditions (or an increase in hydrogen sulfide concentrations) of the Early Ordovician are also ...
[47] [48] Brain expansion (enlargement) between 0.8 and 0.2 Ma may have occurred due to the extinction of most African megafauna (which made humans feed from smaller prey and plants, which required greater intelligence due to greater speed of the former and uncertainty about whether the latter were poisonous or not), extreme climate variability ...
The Eocene–Oligocene extinction event, also called the Eocene-Oligocene transition (EOT) or Grande Coupure (French for "great cut"), is the transition between the end of the Eocene and the beginning of the Oligocene, an extinction event and faunal turnover occurring between 33.9 and 33.4 million years ago. [1]
Summer: A poll of more than 600 paleontologists and other Earth scientists found 24% to support the impact hypothesis of the Cretaceous–Paleogene extinction event, 38% agreed that the impact occurred but was not the true cause of the mass extinction, 26% denied that any impact had occurred and 12% completely denied the occurrence of a mass ...