Here’s a few highlights from the history of the Earth and life during the Mesozoic Era, the second Era of the Phanerozoic, which is the fourth Eon in Earth’s history. These events are mainly focusing on North America, and the dates for Periods and Epochs have been partially rounded. MESOZOIC (MZ) [251 – 65 Ma]… Continue reading Highlights of the Phanerozoic: Part 2 – Mesozoic [251 – 65 Ma]
Tag: science
Highlights of the Phanerozoic: Part 1 – Paleozoic [542 – 251 Ma]
Here’s a few highlights from the history of the Earth and life during the Paleozoic Era, the first Era of the Phanerozoic, which is the fourth Eon in Earth’s history. These events are mainly focusing on North America, and the dates of Periods and Epochs are partially rounded. PALEOZOIC ERA [542 - 251 Ma] CAMBRIAN (Є)… Continue reading Highlights of the Phanerozoic: Part 1 – Paleozoic [542 – 251 Ma]
A tale of two CaCO3’s — Calcite and Aragonite
Aragonite (left) and calcite (right), both CaCO3; image by author Here in this photo, we clearly have two different minerals–one aragonite and the other calcite. However, they both have the same chemical formula of CaCO3. So how can it be that these two different minerals are both calcium carbonate? Aragonite and calcite are polymorphs of… Continue reading A tale of two CaCO3’s — Calcite and Aragonite
Crystal Cave diorama in Coors Mineral Hall at the Denver Museum of Nature & Science. Depicts a selenite and calcite grotte form the Naica Crystal Cavern in El Petosi, Mexico Image by author
What are these things? — Stylolites
See these thin little squiggly gray lines in the rock in the photo above? These are what you call stylolites. Stylolites are caused by pressure dissolution, meaning that a large amount of stress was applied to the rock in a direction perpendicular to which to stylolites are formed. Because of this pressure applied, there’s a dissolving… Continue reading What are these things? — Stylolites
Words to know: Palimpsest
On my very first ever day of geology class, my geology professor introduced me to the word palimpsest, which is a text written over other texts. Normally the word is used to describe parchments in which the original writing has been removed and written over by new writing, However, the Earth itself truly is the ultimate… Continue reading Words to know: Palimpsest
Some perspective on (geologic) time [w/ the Acasta gneiss!]
Due in large part to the lasting legacy of Christopher Columbus’s expeditions, North and South America will forever bear the mark of the “New World.” Whereas Europe has cathedrals centuries older than the United States itself, North America appears to not be able to offer much in terms of relics of antiquity. The earliest humans… Continue reading Some perspective on (geologic) time [w/ the Acasta gneiss!]
Denver Museum of Nature and Science, Prehistoric Journey
Field Museum of Natural History, Evolving Planet
A message from a geologist to people who believe in “overlapping magisteria”
In the ever persistent spirits of Clarence Darrow and William Jennings Bryan, Bill Nye the “Science Guy,” and Ken Ham, president of the Creation Museum, had a good old-fashioned evolution vs. creationism debate earlier last month. However, this “debate” that Nye and Ham have once again re-ignited is futile, seeing as there can never actually… Continue reading A message from a geologist to people who believe in “overlapping magisteria”
Emily Zawacki, Ph.D. 