Geological Sciences | Science Communication
via Rapid glacial advance reconstructed during the time of Norse occupation in Greenland Boulder, Colo., USA: The Greenland Ice Sheet is the second largest ice body in the world, and it has the potential to contribute significantly to global sea-level rise in a warming global climate. Understanding the long-term record of the Greenland Ice Sheet,… Continue reading Rapid glacial advance reconstructed during the time of Norse occupation in Greenland
via Records from Lake Magadi, Kenya, suggest environmental variability driven by changes in Earth’s orbit Boulder, Colo., USA: Rift Valley lakes within eastern Africa range from freshwater to highly alkaline systems and are homes to diverse ecosystems. These Rift Valley lakes are also sedimentary repositories, yielding a high-resolution environmental record that can be targeted to… Continue reading Records from Lake Magadi, Kenya, suggest environmental variability driven by changes in Earth’s orbit
Especially in the news as of late, there has been a lot of talk as to whether politicians “believe” in climate change. Framing the question like this makes it seem as though climate change is in the league of Santa Claus or the Easter Bunny—things that require belief for their existence. However, climate change doesn’t… Continue reading Yes, climate change is real—and we’re causing it
Direct measurements for global temperature only date back to about 1850, so how do we figure out what past climates were like? Once we move beyond the limits of direct measurements, we need to use proxies—preserved physical characteristics of past environments. Oxygen isotopes are the most commonly used paleoproxy to reconstruct long records of past… Continue reading Oxygen Isotopes and Paleoclimate
[Also formerly known as the Cretaceous-Tertiary (K-T) and now as the Cretaceous-Paleogene (K-Pg) extinction] Severity: 5th worst Cause: Meteorite impact released CO2 from carbonates Climate: Cold (SO2) then warm (CO2) Aftermath: Mammals arise Even though the End-Cretaceous is the least severe of all the mass extinctions, with 62% of species and 11% of families wiped… Continue reading Mass Extinction Monday | END-CRETACEOUS (65 Ma)
Severity: 4th worst Cause: Central Atlantic Flood Basalts, meteorite impact (?) Climate: Hot; Pangaea mostly desert Aftermath: Dinosaurs diversify Only 50 My after the End-Permian extinction, 65% of species and 12% of families were wiped out during the End-Triassic extinction. The exact cause of this extinction is still not very well constrained. It could possibly… Continue reading Mass Extinction Monday | END-TRIASSIC (200 Ma)
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)
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)
Here’s a few highlights from the history of the Earth and life during the Cenozoic Era, the third of the Phanerozoic, which is the fourth Eon in Earth’s history. These events are mainly focused on North America, and the dates of Periods and Epochs are partially rounded. CENOZOIC (CZ) [65 Ma – on] PALEOGENE (PE)… Continue reading Highlights of the Phanerozoic: Part 3 – Cenozoic [65 Ma – on]
Emily Zawacki, Ph.D. 