avogadros_number OP t1_j8lt3mi wrote on February 15, 2023 at 6:27 AM

Reply to comment by [deleted] in During the mid-Cretaceous approximately 94.5 million years ago the worlds oceans became nearly uninhabitable as rapid degassing of volcanic carbon dioxide altered seawater carbonate chemistry, triggering a global-scale episode of reduced marine oxygen levels known as Oceanic Anoxic Event 2. by avogadros_number

They absolutely are. Of all of the mass extinction events and minor extinction events, one of them (the end-Cretaceous) is more commonly attributed to bolide impact, though not without prior effects from the Deccan Traps. The End-Permian (Siberian Traps), and End-Triassic (Central Atlantic Volcanic Province - CAMP) are certainly attributed to volcanism, as are a number of other extinction events such as AOE 2 and others. Not all large impact events lead to extinctions or mass extinctions (> 75% of all species go extinct within a relatively short geological time span). For example, the Manicouagan Impact Crater, located in Quebec, Canada has a diameter of ~100 km and occurred more than 12 million years before the end of the Triassic with no extinctions associated with the event.

The greatest cause of extinction events - mass or otherwise, whether from volcanism, impact events, orbital cycles, etc. results from the subsequent changes in atmospheric and ocean chemistry. This doesn't bode well for our current climate trajectory.