Guest Video: The Salton Sea


A study at the end of June made headlines about earthquake hazard on the San Andreas Fault. The research looked at the area covered by the Salton Sea:


https://youtu.be/-OqrZG-EBaQ&rel=0


According to news reports, geologists found:

. . . a nearly 15.5-mile-long, sheared zone with two, nearly parallel master faults and hundreds of smaller, rung-like cross faults. . . The discovery . . . reveals the southern tip of the San Andreas Fault changes fairly gradually into the ladder-like Brawley Seismic zone. The structure trends northwest, extending from the well-known main trace of the San Andreas Fault along the Salton Sea’s northeastern shore, to the newly identified East Shoreline Fault Zone on the San Andreas’ opposite edge.

. . .

Future earthquakes in that zone or near the San Andreas Fault could potentially trigger a cascade of earthquakes leading to the overdue major quake scientists expect along the southern San Andreas fault zone . . .

So, perhaps it’s good that the “Riviera” scheme never worked out.

While seismologists scramble over the area to learn more about earthquake hazards, the USGS is monitoring the local volcano situation–which includes five vents discovered in 2013–through the California Volcano Observatory.

Again, not a good place for a resort!


Featured image: 12019, at Pixabay. Public domain.


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Guest Videos: Gneiss and Gold


It’s great to go for a hike with someone who knows what they’re looking at.


https://youtu.be/ptYmrw06P6M&rel=0


Wait. Gold? You’re ending the video right after mentioning gold?

Well, let’s head up to the Yukon and get some gold in the pan!



But how do you know that the shiny yellow stuff you’ve just collected is gold, not pyrite?



Featured image: Acasta gneiss from Canada, by Mike Beauregard, CC BY 2.0. The yellow color is probably lighting; this rock’s value is only in its age: over four billion years old!


Guest Videos: Vermilion Cliffs National Monument


Sometimes geology pulls out all the stops. You might have seen pictures of this place calling it “The Wave,” for obvious reasons.

This amazing place, sculpted by water and wind in an arid region, is just one step in a geological “grand staircase” of sedimentary rocks that stretches from Bryce Canyon down into the Grand Canyon.

Here is a drone’s view, followed by a Bureau of Land Management video that makes you wonder how native people, European explorers, and other vistors ever made it through alive!





A Very Addictive Online Dinosaur Site


Between working on the ebook and keeping up with Kilauea (see “live” blog link in upper right corner of the page), I can only put up some guest videos to thank people for coming here.

However, I found this site, first with the interactive globe that shows what position the continents were in down through geologic time.

For example, you have heard that a big asteroid hit the Yucatan 65 million years ago and caused a mass extinction, right? And you picture an impact on modern-day Mexico.

But the continents were arranged somewhat differently back in the day:

Continue reading

Guest Videos: Sentinel Spots Suspicious Movement of English Village


Not in the village, of the village.

Here’s the village–I don’t know why the bicyclists are driving cars, but that’s Willand in Devonshire they’re driving through:


And this is the Sentinel that has discovered Willand is rising at a rate of almost an inch a year


It’s a total mystery. This is not a tectonically active region, so things like volcanism or plate collisions are unlikely to be involved. The mining boom during the Industrial Age also passed Willand by.

According to this source, whatever is causing it is deep underground, perhaps an aquifer that is filling up.

Willand residents aren’t endangered by the movement, but it will affect major transportation corridors that are planned for the area.


Guest Video: Lake Baikal


Here is a video of a very famous lake. It’s exceptional because there are people in almost every shot, but you never lose sight of the scale.

Those cracks and bubbles are so spectacular because the water of Lake Baikal is very clear.

The geology behind Baikal–the oldest and deepest lake on the planet–is complicated, even for the experts. Some think it’s a result of the distant India/Asia continental collision. Others think that there might be a mantle plume far underground, forcing the continent to spread apart here.

Whatever is going on has built something awesome at this moment of geologic time. When spring comes, you need a satellite to see the ice melt on this lake!


Guest Videos: Splitting Continents Help Humans Evolve


We worry about climate change today, but down through time people have adapted to a lot of geological drama.

In mid-March this year, scientists reported that geologically rapid changes in the landscape of the East African rift affected Stone Age people living there.

The researchers apparently are studying cultural development, but I’ve come across this idea before, that the tectonic changes in Africa’s Great Rift system created a more varied landscape that gave early people many opportunities to develop agility and intelligence.

But the main reason for this post today is to share with you this delightful video on human evolution. I came across it while researching the reported study background. Enjoy!


Featured image: Misty Kenya sunrise, Thomas Kriese. CC BY 2.0.



Guest Video: Tracking Sauropod Dinosaurs


While my focus these days has narrowed substantially from the original book concept–how the world’s apex predators went from T. rex to cats–news this week about finding the biggest dinosaur tracks ever caught my eye.

It was sauropods walking in Jurassic mud that is now stone in Scotland. Trackways like this are the only tangible evidence we have of long-extinct animals as they existed as living beings at a precise moment in geologic time.

Looking at tracks is a really exciting visceral experience, though scientists generally don’t get this wonderfully enthusiastic:

Environments often change dramatically down through time, but Utah back in the day actually was a desert, though perhaps dinos left these tracks during one of the high-sea-level times.

Things were a lot wetter in Middle Jurassic Britain.

Those huge tracks that recently made headlines came from sauropods wading in one of the many lagoons that pooled together on a Mid-Jurassic British coast where shallow seas and river deltas came together.

Tyrannosaurs were theropods. Sauropods were veggie dinosaurs–the biggest ones of all.

Can you imagine how much vegetation a herd of those giants went through in one day? Scientists are working on it.


Guest Videos: Zealandia, the Eighth “Continent”


We have all heard the legend of Atlantis, but there really is an ancient sunken landmass just east of Australia that scientists, who just trekked there in 2017, call Zealandia.

Check it out!

GNS Science shows the economic zone in this video, as well more scientifically appropriate stuff, because this underwater extension of New Zealand was discovered and recognized under international law for economic reasons.

It’s not officially a continent yet, perhaps only because of how words and job descriptions are defined.

The region’s very complex and active geology is why New Zealand is above sea level today.

Zealandia did not go gently into the dark marine depths.


Featured image: National Oceanic and Atmospheric Administration. Public domain.


Guest Videos: The Hidden Secrets of Minerals


Bubbles happen. And sometimes they are awesome.

Here is a bubble that formed inside of sea salt in a solution that a student at Finland’s Tampere University of Technology was making.

Gas pockets also form naturally in halite (rock salt). These are even more awesome because this air is the atmosphere as it was back in the day, not what we have today. Such air bubbles allow Earth scientists to directly study conditions in the distant past.

This recently made the news when researchers analyzed 800-million-year-old air found in Australian halite and found more oxygen than they expected. The discovery could change our understanding of how early animals evolved.

Inclusions have been found in volcanic rocks, too.

Molten rock degasses–this is why volcanologists measure CO2, sulfur, and other gases on a sleeping volcano. As magma rises toward the surface, those gas levels increase. It’s a way to see inside the volcano before it erupts.

Some gas remains in lava after it has erupted. There isn’t much and it’s not as easy to measure as a gas bubble, since what was once molten rock is now frozen. This is why melt inclusions are solid and glassy. (Oppenheimer)

Nevertheless, there is sometimes enough gas left for scientists to get an idea of how much climate-changing gases an ancient eruption released. (Self and Rampino)

For instance, one reason the Deccan Traps flood basalt in India is sometimes associated with the dinosaur-killing K-Pg mass extinction (in addition to the asteroid impact) is because its eruption may have released at least 200 times as much sulfur as the 1991 eruption of Mount Pinatubo (Oppenheimer), whose sulfur cloud cooled the world 1 degree Fahrenheit between 1991 and 1993.

Melt inclusions also convey a lot of information about the physical conditions at the source of the magma they formed in, many miles below our feet.

And then there are Hadean zircons. These small crystals found in igneous rock contain information that is changing how we picture the very early Earth.

Mineral inclusions in antarctic zircons also provide clues about what was going on back in the Hadean.

Perhaps the biggest inclusion-related surprise for geoscientists is the discovery of tistarite–a very rare titanium-based mineral–in melt inclusions found in rock that was erupted during the Cretaceous in what is now northern Israel.

How rare is it? Tistarite formed along with the Solar System and only one grain of it has been found in a meteorite. No one suspected there was any on Earth.

Now it looks like geologists may have to rewrite their textbooks on the deep Earth’s geochemistry!


Featured image: Eurico Zimbres. CC BY-SA 2.5.



Sources:
Oppenheimer, C. 2011. Eruptions That Shook the World. Cambridge: Cambridge University Press. Retrieved from https://play.google.com/store/books/details?id=qW1UNwhuhnUC

Self, S., and Rampino, M. 2012. Flood basalts, mantle plumes and mass extinctions. The Geological Society. https://www.geolsoc.org.uk/flood_basalts_1 Last accessed March 23, 2018.