Seawater isotope ratios through time: sulfur and carbon

Low sea levels = heavy carbon, light sulfur in seawater

  • Low sea levels = more land space for plants = plants use lighter carbon = lighter carbon stuck on land = heavy carbon in the sea!
  • Low sea levels = less habitat for sulfate-reducing bacteria = less light sulfur in pyrite = more light sulfur in the sea!

High sea levels = light carbon, heavy sulfur in seawater

  • High sea levels = less space for plants = less light carbon uptake by plants = light carbon in the sea!
  • High sea levels = expanded habitat for sulfate-reducing bacteria = more light sulfur in pyrite = less light sulfur in the sea!

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Subducted seawater the source of fluid-rich diamonds

Subducting oceanic plates that dive hundreds of kilometers beneath Earth’s surface carry with them cargoes of sediment and seawater. As the plate heats up the deeper it sinks, this seawater not only initiates melting in the rock above it, but can also trigger diamond formation, suggest the authors of a new study in Nature. Read more

How the west was made: western North American orogenies

Western North America is a patchwork is hundreds of terranes, which are crustal pieces or microplates (think of islands), that collided with and attached to North America across hundreds of millions of years -- adding piece-by-piece to the continent's width and building mountains as they produced volcanoes or pushed up sediments and rocks. This posts provides a very simplified timeline of the major orogenies and terranes that affected western North America. For a more in-depth look, see the resources below. Read more

Easy Science: How sinkholes form

Sinkholes can form anywhere that the bedrock dissolves away beneath the soil, but classic sinkholes tend to form in limestone, a carbonate rock composed primarily of the minerals calcite (CaCO3), aragonite (CaCO3), and dolomite (CaMg[CO3]2). Worldwide, limestones cover about 15% of land surface. Twenty percent of the US is susceptible to sinkholes. Read more

Volcanic lightning turns ash into glass

Within the ash plumes of explosive volcanic eruptions, collisions among countless pyroclastic particles sometimes lead to the buildup of static charges that discharge dramatically as volcanic lightning. In a new study, researchers have found that this lightning can, in turn, melt and fuse ash particles into distinctive glassy grains called spherules. Identifying and studying these spherules could help scientists better understand past and future eruptions, the study’s authors suggest. Read more

Grow your own bismuth crystals

Image credit: http://en.wikipedia.org/wiki/Bismuth#/media/File:Wismut_Kristall_und_1cm3_Wuerfel.jpg

Thanks to bismuth's low melting point of 271°C, you can grow your own crystals by melting and then cooling bismuth in a stove pot. A pound of pure bismuth runs $25 (shipping included) -- much cheaper than buying large crystals -- and you can even use molds to create geodes or other shapes. Check out the video, or if you prefer written instructors, see this tutorial. Read more

Metamorphic meat: lava-cooked steaks

Researchers at Syracuse University developed a car-sized furnace, capable of melting up to 800 pounds of basaltic rock into lava, to study how lava flow morphology is influenced by factors such as temperature, slope (of the land), snow and ice, effusion (pour) rate, barriers, lava composition, and surface roughness.

While the furnace has already yielded plenty of helpful data, students found yet another use: cookouts at 1,000°C! No word yet on how a volcano-baked steak tastes, though. Suggested future include s'mores and hot dogs. Watch the video below, and then check out the Syracuse University Lava Project website for photos and descriptions of their work. Read more