This list briefly describes the creatures appeared (and not necessarily when they disappeared, if they did). Keep in mind that all of the creatures listed are marine, and most are soft-bodied invertebrates. Of course, this list doesn't even come close to covering all the Paleozoic creatures, just the ones I found worth mentioning -- if you think I missed one, let me know in the comments! Click on the images to enlarge; hover to see photo credit in alt-text (many are from Nobu Tamura). Read more
Creatures of the early Paleozoic
Cortney Science & Technology + biology, geology, paleozoic
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Basalt types: tholeiites vs alkali basalts
Cortney Science & Technology + geochemistry, geology, hawaii, magma
Essentially, tholeiites are less evolved. They have different normalized rare earth element REE signatures: when normalized by chondrites, the more primitive tholeiites have flatter REE patterns, while calc-alkalis show enrichment in the light REEs (LREE). Tholeiites are associated with oceanic spreading centers (shallow), while alkali basalts are associated with collisional zones (deeper). Read more →
Quick facts about the layers of the Earth
Cortney Science & Technology + earth layers, Easy Science, geology
Here is an easy chart gathering together basic facts about each of the earth's layers, from top to bottom: the crust, the mantle, and the core. The crust and uppermost part of the mantle (down to 70 km) from the rigid lithosphere, which contains tectonic plates, underneath which lies the fluid taffy-like asthenosphere, which drives plate motion. Unsurprisingly, as you travel deeper into the earth, things get denser, hotter, and and more pressurized.
Volcanoes and photosynthesis
Cortney Science & Technology + iron, photosynthesis, volcanoes
We typically think of volcanoes as destructive, but their eruptions could be feeding tiny photosynthetic organisms that live in the ocean.
Primary productivity (how much photosynthesis occurs) in certain areas of the ocean is iron-limited: even though phytoplankton (photosynthetic microscopic organisms) have plenty of all the other nutrients they need, a shortage of iron limits their growth. Read more →
Easy Science: how the Appalachian Mountains formed in four steps
Cortney North Carolina, Science & Technology + Appalachian Mountains, Easy Science, geology
The history of the Appalachians spans over a billion years, with four collisions forming the Appalachian Mountains. The last collision occurred around 300 million years ago. Originally, the chain would have rivaled the Himalayas at over 5 km tall, with some mountains perhaps reaching as high as 9 km. Three hundred million years of erosion slowly whittled the mountains away; today, they average 1 km, with the highest point being 2 km at Mount Mitchell, North Carolina. Read more →
Did a starburst cause Earth to get buried in kilometers of snow?
Cortney Science & Technology + geology, ice ages, snowball earth, starbursts, supernovae, winter nebula
Three times before the Cambrian period (545 mya), the entire earth has been buried in several kilometers of snow -- based on evidence including tropical glacial deposits and the cessation of carbonate production (which prefers to form in warmer waters) -- in a phenomenon known as Snowball Earth. But what causes these drastic glaciations to occur? Read more →
Most common elements and oxides in rock-forming minerals
Cortney Science & Technology + geology, minerals, oxides, rocks
After the Big Bang, the universe was made up of the two lightest elements: hydrogen and some helium. Nucleosynthesis was responsible for creating heavier elements; young stars form helium out of hydrogen.
In the later stages of a massive star's life, helium is converted into heavier elements like carbon, oxygen, silicon, and iron. When a star goes supernova, they create elements heavier than iron. Elements with even atomic numbers are an order of magnitude more common than odd ones. Read more →
Easy Science: cross-section of ocean floor geology
Cortney Science & Technology + basalts, Easy Science, gabbros, geology, oceans, ophiolites, seafloor spreading, sheeted dikes
The ocean floor forms at seafloor spreading centers, where basaltic magma pushes out through cracks. This magma ultimately comes from the mantle. What would you see if we could punch out a 8 km deep tube from the sea floor? Unfortunately, that isn't yet possible, but thanks to ophiolites, which are parts of the seafloor that have been uplifted to where we can study them, we have an idea of what it would look like. Read more →
Easy science: the 5 Big Extinctions explained
Cortney Science & Technology + Easy Science, extinctions, geology
This article is going to very briefly explain what constitutes a "Big Extinction" and sum up in an easily understood manner the causes and effects of the five (or six!) events. Click on the extinction title to go to Wikipedia page where you can find more information, including sources. Note that the simplicity of this article means it excludes important details, controversies, and caveats. Google is your friend. Read more →
Whaling of the Right Whale
Cortney Science & Technology + biology, conservation, marine mammals, right whales, whales, whaling
This article will summarize the history of whaling of Eubalaena glacialis, including why the right whale was favored, how they were captured, killed and processed, as well as the impacts that hunting had on right whale populations.
Written in conjunction with Daniela Benavides with for BIO 376: Marine Mammals at Duke University, Summer 2013. Read more →