Geological Sciences | Science Communication
Severity: 1st worst Cause: Eruption of Siberian Traps Climate: Cold to extremely warm; ocean acidification and anoxia, ozone destruction Aftermath: Permanent ecosystem reorganization; low O2 for >106 years There’s good reason why the End-Permian extinction is referred to as “The Great Dying”; 95% of all species, 53% of all marine families, 84% of marine genera,… Continue reading Mass Extinction Monday | END-PERMIAN (250 Ma) – “The Great Dying”
Severity: 3rd worst Cause: Still unclear, changes in sea level and ocean anoxia (?) Climate: Abrupt cooling Aftermath: Marine filter feeders diversify Rather similar to the End-Ordovician extinction, warm-water marine invertebrates were the hardest hit during the Late Devonian extinction. 22% of known marine families and 57% of marine genera were wiped out during a global cooling event. Gondwana glaciations were… Continue reading Mass Extinction Monday | LATE DEVONIAN (365 Ma)
I thought I’d share my final project from Introductory Geology! I made this back in fall of 2011 when I had no idea I’d be going on to study geology. I was just psyched to be able to use my graphic design skills, and this is still probably my favorite thing I’ve ever made.
Above: A shatter cone in dolomite from the Kentland, Indiana impact structure (Specimen from Lawrence University.) Meteorite impacts are pretty amazing things. An impact crater forms instantaneously on a human time scale, with the shock wave from the impact propagation through the target rock in the following stages: contact and compression, crater excavation, and crater modification. Some… Continue reading Shock metamorphism & shatter cones
Severity: 2nd worst Cause: Some type of C cycle disturbance, not well constrained Climate: Abrupt ice age followed by rapid warming Aftermath: Cambrian organisms (e.g. trilobites) decimated During the End-Ordovician mass extinction, 25% of known marine families and 60% of marine genera were wiped out. Warm-water invertebrates were the hardest hit, as the event was… Continue reading Mass Extinction Monday | END-ORDOVICIAN (440 Ma)
Just got the official email that my GSA abstract has been accepted, so I’ll be heading out to Vancouver, BC in October! I’m giving an oral presentation in The Holey Solar System session, so I’m partially terrified but pretty excited. It’s crazy seeing my name up there with the leading experts in the field of… Continue reading Presenting at GSA!
Starting a new feature here! Every Monday, they’ll be a little overview of each of the five big mass extinctions, To start off, we’re going to do a bit of a general overview. Around 99% of all species that have ever lived on Earth are extinct.1 However, this extinction rate is far from constant, as organisms… Continue reading Mass Extinction Monday!
Typically when you look at a geologic time scale, the Precambrian is all scrunched up, so even though it accounts for about 80% of Earth’s history, you forget how significant it is in the whole scheme of things. Putting the time scale into perspective like this just makes me marvel even more at human existence…… Continue reading ~4.55 BILLION YEARS – TO SCALE!
Emily Zawacki, Ph.D. 