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Posts treating: "basalt"

Saturday, 29 October 2022

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On A Piece of Jurassic Basalt 

Fossils and Other Living Things [2022-10-29 17:19:00]  recommend  recommend this post  (120 visits) info
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  Sliding down upon the slide Seems like it never ends When we get to the other side Maybe then we'll make amends It's the end of time The end of time Can you feel it? Can you feel it? It's the end of the line It's the end of time Lindsey Buckingham End of Time on the album Seeds We Sow (2011) Is there a limit to how much significance a person can ascribe to an inanimate object?  I’m certainly guilty of overthinking nearly everything and may be particularly guilty of that when it comes [...]

WAHINGTON'S PILLOW BASALT RHINOCERAS 

ARCHEA [2021-09-12 11:00:00]  recommend  recommend this post  (52 visits) info
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The Miocene pillow basalts from the Lake Roosevelt National Recreation Area of central Washington hold an unlikely fossil. It is a mould of a small rhinoceros, preserved by sheer chance as its bloated carcass sunk to the bottom of a shallow lake just prior to a volcanic explosion.We have known about this gem for a long while now. The fossil was discovered by hikers back in 1935 and later cast

GIANT'S CAUSEWAY 

ARCHEA [2020-06-30 18:30:00]  recommend  recommend this post  (81 visits) info
The Giant's Causeway is a spectacular expanse of interlocking hexagonal basalt columns formed from volcanic eruptions during the Paleocene some 50-60 million years ago.These columns tell a story of the cooling and freezing of the lava flows that formed them. As lava at the surface cools and freezes, it also shrinks as its molecules rearrange themselves into a solid structure. This happens

Monday Geology Picture: Pillow Basalt Decor 

Georneys [2019-04-29 23:16:16]  recommend  recommend this post  (504 visits) info
This week I’m sharing a picture of a lovely pillow basalt decorative slab that is part of the decor in the Department of Earth, Ocean, and Atmospheric Sciences at the University of British Columbia.  In this slab, you can see pillow shapes outlined by lovely glass rinds, which formed when the basaltic lava rapidly cooled because it was erupted underwater. I just love this decorative slab — who wouldn’t want … The post Monday Geology Picture: Pillow Basalt Decor appeared first on [...]

Geology of the Galapagos Islands 

Mountain Beltway [2019-01-08 13:02:02]  recommend  recommend this post  (120 visits) info
Dozens of delectable geological images from the Galapagos Islands, showing fluid basalt flows and violent pyroclastic deposits along with many primary volcanic features (and a bit of sedimentology thrown in for good measure). The post Geology of the Galapagos Islands appeared first on Mountain Beltway.

Mafic volcanics atop felsic instrusives: Sonora Pass, California 

Mountain Beltway [2018-06-25 14:21:54]  recommend  recommend this post  (602 visits) info
Sonora Pass, California, is a lovely place to examine a volcanic-on-plutonic nonconformity that spans about 80 million years of missing time. Let's check it out on a photo-rich virtual field trip! The post Mafic volcanics atop felsic instrusives: Sonora Pass, California appeared first on Mountain Beltway.

Monday Geology Picture: Pele’s Hair 

Georneys [2018-01-22 22:17:42]  recommend  recommend this post  (512 visits) info
For this week’s post, here’s a picture showing a lovely example of Pele’s Hair, which is a type of volcanic glass that consists of fibers or thin strands. Although I’ve visited many volcanoes (including a few active ones) over the years, I’ve never seen Pele’s Hair in the field. So, I was quite happy to see this excellent example in the volcano museum on Réunion Island. I visited the museum during

Monday Geology Picture: Pretty Pahoehoe 

Georneys [2017-10-30 19:42:48]  recommend  recommend this post  (31 visits) info
For this week’s picture, here’s another lovely shot of pahoehoe basalt that I took during a March 2017 vacation to Réunion Island. I previously shared a picture of some Réunion pahoehoe

Monday Geology Picture: Basaltic Weathering 

Georneys [2017-10-23 22:56:15]  recommend  recommend this post  (20 visits) info
For this week’s picture, here’s an image of a relatively young basaltic surface weathering. You can see yellow-green olivine crystals weathering out of the dark matrix. Olivine is one of the first minerals to weather out of rocks, so you can tell that these basalts must be young. Older basalts generally don’t contain fresh olivine, at least not any crystals that you can easily identify with the naked eye. I

Monday Geology Picture: Sani Pass, Lesotho 

Georneys [2017-10-09 08:00:00]  recommend  recommend this post  (42 visits) info
For this week’s geology picture, here’s a shot that I took last year when I visited Sani Pass, which is one of the ways to enter Lesotho. The country of Lesotho is located high up in basaltic mountains, entirely above 1,000 m. You can see basaltic cliffs on either side of this picture. The basalts erupted approximately 180 million years ago and are part of the Karoo Large Igneous Province. I’ll

Monday Geology Picture: Posing with Pahoehoe 

Georneys [2017-10-02 22:06:59]  recommend  recommend this post  (53 visits) info
First of all, for this week’s “Monday Geology Picture” enjoy this fantastic picture of me sitting on some pahoehoe lava earlier this year, when I visited Réunion Island back in March. Second of all, let me provide a little explanation about why I have been terribly negligent of this blog over the past few months, despite my best intentions at the beginning of the year. In January I fully intended to read one science

Friday fold: bend in a vesicular lava flow, Etna 

Mountain Beltway [2017-09-22 19:39:05]  recommend  recommend this post  (143 visits) info
It’s the First Friday of Fall! Here’s a sort of fold to help you celebrate: a section through a ∧ shaped bend in a vesicular basalt flow from the eastern flanks of Mount Etna in Sicily. It’s due to volcanic lava flowing rather than ductile deformation of a pre-existing solid rock (our usual habit with this feature), but I think we can appreciate it

Volcanic Flows in Hawai'i: Life Finds a Way (to destroy rocks) 

Geotripper [2017-06-10 02:40:00]  recommend  recommend this post  (144 visits) info
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Ohi'a Lehua (Metrosideros polymorpha) clinging to a crack in a 1974 lava flow on Kilauea I had kind of a schizophrenic (split-brain) response in regards to what I wanted to accomplish with this post. A couple of weeks ago while still in Hawai'i, I did a post on what I considered the ultimate wilderness on planet Earth, the nearly lifeless high-altitude basalt flows of Mauna Loa on the

Answer to a Hawaiian Mystery, and a Cautionary Tale 

Geotripper [2017-06-02 09:52:00]  recommend  recommend this post  (134 visits) info
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If you've had a geology or earth science course, do you remember what you learned about basalt? Basalt, the low-silica volcanic rock, the one that flows instead of exploding. The one that isn't all that dangerous. Even if you haven't had such a class, you've heard that visiting volcanoes on the Hawaiian Islands is one of the things tourists can do. Helicopters fly over the lava flows,

Here's a Hawaiian Mystery for You: Where Did These Circles Come From? 

Geotripper [2017-05-25 09:54:00]  recommend  recommend this post  (185 visits) info
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We were on a desolate plain on the south side of Kilauea Caldera on the Big Island exploring the ongoing volcanic activity. The smoking pit of Halemaumau Crater with her bubbling lake of molten lava was only a half mile or so north of us, so yes, we were in a closed area (but legally in this instance!). Given that no part of the exposed Kilauea shield is older than about 1,000 years,

Monday Geology Picture: Pahoehoe Lava Flow 

Georneys [2017-05-15 20:42:37]  recommend  recommend this post  (142 visits) info
For this week’s “Monday Geology Picture” here’s a stunning example of a pahoehoe lava flow. I took this picture back in March when I visited Piton de la Fournaise volcano on Réunion Island. I’ll be sharing more pictures from Réunion soon – stay

Volcanoes in the Mist (and underground): Travels in Death Valley 

Geotripper [2017-02-28 01:24:00]  recommend  recommend this post  (117 visits) info
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The Inyo Mountains, in any other setting in the world, would be considered a major mountain range, preserved as a national park perhaps, and celebrated as scenic wonderland. But just like an accomplished sibling overshadowed by a more famous brother or sister, the Inyos lie across the valley from the most spectacular part of the Sierra Nevada, and south of the higher White Mountains. For

Basaltic strata, faulting, and glaciation in western Iceland 

Mountain Beltway [2017-02-07 15:40:50]  recommend  recommend this post  (84 visits) info
Today, let’s journey to Iceland, to a bit northwest of Reykjavík. This is a view from the top of the Grábrók cinder cone, across the valley to the east. With very few exceptions, Iceland is a big pile of basalt, and that shows through in the walls of this valley, which display a stack of basaltic lava flows, intercalated in places with pyroclastic debris or volcaniclastic sediment. One portion of

Oddball Icelandic rocks, part I: A green ignimbrite 

Mountain Beltway [2016-10-06 20:28:06]  recommend  recommend this post  (90 visits) info
Iceland does basalt really, really well. But there are a few non-basaltic igneous rocks to be found there, too. One of them is a green ignimbrite (pyroclastic conglomerate) that crops out in coastal Berufjörður, eastern Iceland. Check it

Stađarbjargavík 

Mountain Beltway [2016-09-21 14:47:14]  recommend  recommend this post  (61 visits) info
Based on this photo, what do you think Stađarbjargavík might have to offer? If you guessed columnar jointing in basalt, you’d be right! Looking down the fjord, south of Hofsós (in Iceland): The place is basically a series of miniature Giant’s Causeways, full of unpopulated exemplars of cooling columns! Little coves separate the small peninsulas, each filled with rounded column bits: Here’s a spot where one more is about to
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