Posts

August 19, 2014

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7:01 PM | Geo 730: August 19, Day 596: Pyrite Patch
I *think* this is the same patch of pyrite as seen in yesterday's photo, but from more of a head-on perspective. The rock here is tough, and highly silicified. For the most part I tend to pull out "the heavy artillery," that is, a sledge hammer, for this stop (in the top right, a four pound hand sledge). It's definitely a spot for eye protection, and even with that, flying splinters can draw blood. But kids loved it; it was obvious they were willing to risk an owie and a Band-Aid for a piece of […]
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2:19 PM | The Odd Natural History of San Francisco
Our co-producer, Miles, gives a talk about San Francisco’s hidden nature that is simultaneously informative, funny, surprising and slightly uncomfortable (you’ll know what we mean when you get there). From the gold rush to the bay to the delicious food, … Continue reading →
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6:24 AM | Curiosity Scrubs Mars Rock, Possible Drilling Target
As Mars rover Curiosity looks to line up its fourth drilling target, it needed to give a rock a bit of a scrub. Continue reading →
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12:17 AM | Geo 730: August 18, Day 595: We're Golden
In the lower right, you can see the draw of this quarry for kids in particular, but adults as well. Pyrite (and perhaps small amounts of chalcopyrite, too) are disseminated throughout much of the rock, but can form nice patches, as well as aggregations of small cubes, along joints and fractures. If you look carefully, especially at the photo in full size, you'll spot pyrite across this entire surface. The evidence for chalcopyrite is that on slightly weathered surfaces one can often spot […]

August 17, 2014

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11:01 PM | Geo 730: August 17, Day 594: Altered Rhyolite Dike (?)
By this point of the Quartzville trip, the rocks are getting consistently weird. Above is a case in point. In this (perhaps temporarily) disused quarry, it looks as if the target rock was hydrothermally altered rhyolite, and it looks as if the rhyolite occurs in a dike, seen as horizontally jointed columns toward the back. The reason for the tentative "looks," though, is twofold. First, ALL the rock is so cooked and altered that it's difficult to tell with certainty what the protolith was, and […]
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10:12 PM | Geo 730: August 16, Day 593: Charcoal-Grilled Strawberries
Well, at least the plant at my fingertip looks like a wild strawberry to me. Though it's not really grilling, and that's not really charcoal. Pretty much all the rock visible in this photo is ancient charcoal, completely infused and filled with quartz. This is at the east/upstream end of the outcrop, where the base of the "wood" containing breccia-like rock comes down to near the road level, (Dip is to the east here.) and it's actually reachable. Elsewhere, you can't get at the apparently […]
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8:54 PM | Geo 730: August 15, Day 592: Plants, Old and New
The new plants are pretty obvious, though browning in the early August heat. The old "plant" is not so obvious, but easy to spot once you know what to look for. See the black splotch in the bedrock, occupying the central portion of the photo? That's a large block of what seems to be permineralized charcoal. About a month ago, I posted a microscopic view of this material. It's weird stuff. The carbon in the charcoal is preserved, unmodified, but all the pore space has been filled with quartz. As […]
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3:01 AM | Quantifying Earthquake Hazards In The Pacific Northwest - It's Complicated
Nearly forgotten research from decades ago complicates the task of quantifying earthquake hazards in the Pacific Northwest, according to a new report.The report focuses on the Cascadia subduction zone—a giant active fault that slants eastward beneath the Pacific coast of southern British Columbia, Washington, Oregon, and northern California. Geologic studies in the past three decades have provided increasingly specific estimates of Cascadia earthquake sizes and repeat times. The estimates […]

August 15, 2014

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8:17 PM | Geo 730: August 14, Day 591: A Slick Close-Up
This is typically what slickensides look like in the field. Though this is somewhat weathered, and heavily colonized by lichen (light spots) and moss (dark green spots), the scratches, aka striations, are clearly evident. At the very least, these striations are so-called "bidirectional indicators," meaning that their orientation gives the observer two possible directions for offset. In this case that would be to the left and down about 20 degrees, or to the right and up about 20 degrees. In […]
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6:45 PM | Geo 730: August 13, Day 590: Feelin' Groovy
Interzone's WiFi has been acting pretty rotten for several days now, and I had to run some errands yesterday, so things have become a bit backed up here at OTI. I'll try to get caught up today. Above, we can see some of the larger-scale gouging of the slickensided cliff up Quartzville road. Groovy, man!Photo unaltered. July 9, 2012. FlashEarth Location.
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3:59 PM | Guns, Bones and Polar Bears
The Spitsbergen Jurassic Research Group, led by National Geographic Explorer Dr. Jørn Hurum, is blazing its next great expedition to the icy rim of the world in search of stunningly preserved fossils. Polar bears are an ever-present threat to the fossil-hunters, but the team takes precautions to avoid unnecessary violence.
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3:00 PM | The Schiller Effect Makes Stone Seem to Light Up Internally
This rock isn't being lit from behind and it's not see-through. It, like others, seems to light up internally. This internal glow baffled people for centuries, until a combination of physics and geology gave us a clue as to cause of the Schiller Effect.Read more...

August 14, 2014

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7:17 PM | Parks Attract Affluent Homeowners to Earthquake Fault Zones Despite Risks
The Alquist-Priolo law keeps new homes away from active earthquake faults. But a study finds that the resulting "fault zone parks" attract wealthy residents despite the seismic hazard.
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5:00 PM | Stressing Faults From Slow-Slip Earthquakes May Portend Doom For Tokyo
Tokyo is a city of more than 13 million people and they are no strangers to earthquakes. The city, like much of Japan, has been devastated by earthquakes in the past and likely will be again - but when? Ongoing slow-slip earthquakes can't usually be felt at the surface but they play a role in relieving or building up geological stress and recent research examining plate movements under Tokyo has found that, since the massive magnitude-9 Tohoku earthquake and tsunami in March 2011, recurrence […]
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4:29 PM | Mars Rolling Rock Ends Up As Standing Stone
An orbiting Mars camera has spotted the aftermath of a fun event on Mars: A boulder that has rolled down a steep slope -- and ended up resting on its long axis as a standing stone. Continue reading →

August 13, 2014

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7:38 PM | Day Creek Mesa
This DEM (digital elevation model) of the Skagit River valley shows the river has been systematically eroding away an older river valley floor. In the image above dark green is lowest elevation white/gray is highest.A closer look shows the active channel migration area in the green colors shows lots of active channel movement back and forth that on occasions bumps up against the sides of the old valley floor in this area near Day Creek. The older valley floor can be seen in the brown to light […]
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12:44 PM | Midnight Sun Fun
The Spitsbergen Jurassic Research Group, led by National Geographic Explorer Dr. Jørn Hurum, is blazing its next great expedition to the icy rim of the world in search of stunningly preserved fossils. The midnight sun circles in an endless, natural rhythm as the team digs through perplexing terrain.

August 12, 2014

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11:29 PM | Geo 730: August 12, Day 589: Dana For Scale
Another shot of the slickensided cliff face, on another trip, with Dana for scale. One thing that I learned on the trip this year is that I normally visit this spot fairly early in the day, before the sun has come around to illuminate it. We started out two or three hours later than usual on the most recent trip, and the difference in photo quality with and without much direct light is striking. The difference in person, maybe, not so much. But in person, other qualities, such as texture and […]
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7:19 AM | How Sandstone Arches are Formed
Stress and pressure.  We all feel it from time to time and for humans, it’s typically perceived as destructive.  For sandstone arches, however, stress and pressure are indispensable formative elements. Until […]

August 11, 2014

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9:44 PM | Geo 730: August 11, Day 588: Now That's Slick!
If you looked closely at the cliff below the volcanic neck in yesterday's photo, you might notice it seems to have a lineation to it, a pattern of what appear to be scratches (or you might not, it's subtle). However, in this closer view, the scratches are pretty much unmistakeable. These are slickensides, formed when two surfaces in a fault ground past each other during fault movement- which would have been perceived on the surface as one or more earthquakes. In the case of this cliff, the […]
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3:14 PM | The Long Life of Death Valley
Geologist Nicholas Christie-Blick has studied the Death Valley region for more than four decades. Each spring, he leads a group of Columbia University undergraduates there on a fieldtrip. Check out highlights from this year's trip.
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2:38 AM | Thoughts Far From Washington: Sinjar, Northwest Iraq
The plight of the Yazidis is a terrible thing. I was curious about the Yazidis situation and the mountain they had fled to. So while doing some DEM (digital elevation model) work I paid a visit to northern Iraq and found Mount Sinjar. The town of Sinjar is at the base of the south side of the mountain. The DEM clearly shows the mountain is a classic double plunging anticline with the younger rocks tilted up on either side of the fold and the older rocks in the center. Sinjar is […]

August 10, 2014

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11:29 PM | Geo 730: August 10, Day 587: Volcanic Neck II
Similar perspective compared to yesterday's shot, but with this one, @Geohols has walked into the frame, and her husband has driven their vehicle in as well. This doesn't give a good sense of scale (the truck is still a good 30-40 feet in front of the cliff, so there's a parallax issue), but it does give a better sense. With the pinnacle up on a cliff, and essentially inaccessible as far as I'm concerned, that's the best "for scale" you're going to get with this. Speaking of that cliff, […]

August 09, 2014

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7:21 PM | Geo 730: August 9, Day 586: Volcanic Neck
Volcanic necks (aka, chimneys, throats, plugs, etc.- I don't know if there's a "correct" term) such as this are pretty common in the Western Cascades, where thousands of feet of overlying volcanic and volcanic-derived debris has been removed by millions of years of erosion. For the most part, these "old Cascades" have not seen eruptive activity since the Pliocene, about 5 million years ago. The roughly cylindrical conduits that carried magma toward the surface, once cooled, are often more […]
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12:02 AM | Geo 730: August 8, Day 585: Alteration Gradient
A final panorama of this alteration zone, shot from the pullout on the opposite side of the road, which shows the gradient from more or less unaltered rock down the hill to very highly altered in the area of the calcite veins. From here, we'll walk down the hill to the curve visible on the far right. There's a couple of fun surprises waiting behind the Douglas firs along the right edge of the photo...Photo stitched in HugIn, otherwise unaltered. July 8, 2012. FlashEarth Location.

August 08, 2014

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10:20 PM | Most Of What You Need To Know About Planet Earth, In Seven Minutes
This gorgeous animation by the folks at Kurzgesagt (previously ) tells you nearly everything you need to know about our home planet. Read more...
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9:57 PM | 32 Hours in Iceland
I’m in Keflavik International Airport waiting for my flight to Denmark. It’s only been 32 hours since I arrived in Iceland, but in that short time I’ve bared witness to more natural beauty than I ever expected, and been introduced to a country that is quirky, friendly, and so full of new experiences to be [...]
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5:18 PM | The Rocks Remain
Victoria Beach, Lake Winnipeg, 2014 Along Lake Winnipeg in July it felt like business as usual. At Victoria Beach we rode our bikes down narrow gravel lanes through swarms of dragonflies and clouds of midges, basking in the perfect warm air and golden sunlight. The shop, bakery, tennis courts, and playground were busy. But what about […]
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3:53 PM | A Girl Swept Away By the Tsunami In 2004 Gets Reunited With Her Family 10 Years Later
The tsunami that struck Indonesia in 2004 was one of the mostly devastating and deadly natural disasters in modern history. On the 26th of December, 2004, an underwater earthquake near the island of Sumatra triggered a number of massive tsunami waves, some up to 100 feet tall. The tsunamis killed more than 230,000 people in 14 […]
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1:00 PM | Lumps of Clay
Do you ever think much about what clay really is? A while ago, we were at Bald Head Island, NC and spent some time on the beach. I enjoy walking on the beach and looking for interesting shells, etc. Something unusual caught my attention this time. A moist, brown/grey lump, roughly oval, covered with sand. […]The post Lumps of Clay appeared first on Stay Curious.
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