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The Earth Story

@earthstory / earthstory.tumblr.com

This is the blog homepage of the Facebook group "The Earth Story" (Click here to visit our Facebook group). “The Earth Story” are group of volunteers with backgrounds throughout the Earth Sciences. We cover all Earth sciences - oceanography, climatology, geology, geophysics and much, much more. Our articles combine the latest research, stunning photography, and basic knowledge of geosciences, and are written for everyone!
We hope you find us to be a unique home for learning about the Earth sciences, and we hope you enjoy!
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Rediscovering the map that changed the world

“The map that changed the world” doesn’t need much of an introduction — we have written about William Smith’s groundbreaking map twice before (http://on.fb.me/1C7HZPB & http://on.fb.me/1bPAaco ) and was the world’s first geologic map to be copied for wider use in the geologic community. A map of the British Isles’ geologic units, only 70 copies of Smith’s map were estimated to have survived out of about 370 that were originally produced.

As irony would have it, a first edition copy of the map reemerged in the archives of the Geological Society of London, more than 40 years after it was last seen by human eyes. Tucked away in brown, leather-bound case and composed of 15 separate sheets, archivists were aware of the first edition’s survival — the only problem was that they couldn’t find it.

But the map actually benefited from its extended hibernation. The first edition retained its vibrant watercolor finish, which was preserved because it hadn't been exposed to light over a long period of time. Archivists determined that this edition was definitely among the first 50 produced, and perhaps even one of the first 10. The map is currently on display at the Geological Society in London, as part of a series that is celebrating the map’s bicentennial anniversary.

Photo credit: http://bit.ly/1GLiiuI

Further reading: http://bit.ly/1CoGbqd

Visit the map the changed the world:http://bit.ly/1C85hoo

Even more reading if you are up to it:http://amzn.to/1xyMx6f[_

_](https://www.facebook.com/TheEarthStory/photos/a.352867368107647/856573447737034/?type=1&theater#)

Source: facebook.com
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It’s Trilobite Tuesday! The Museum has about 32,000 lots of trilobite specimens, with each lot containing anywhere from one to thousands of examples of these ancient arthropods. Assistant Curator Melanie Hopkins recently took us through a preparation process that helps her identify a given specimen’s species.

Given the subtle differences between one species and another—and there are over 20,000 recognized species of trilobite, spanning 10 orders—correctly identifying a given specimen can be a trying task. The fact that many trilobites, like this one, are very small, doesn’t help!

To make it easier to identify key trilobite characteristics like ridges, spines, and eye stalks, Museum staffers first prepare a batch of ammonium chloride by grinding it into a powder. This chemical, used in fertilizer, cough syrup, and some brands of licorice is a bright white color. That powder is placed in a glass drying tube and heated until it sublimates—transitioning immediately from a solid to a gas. 

As illustrated in the GIF above, Dr. Hopkins uses a plastic bulb attached to the glass one to produce small clouds of ammonium chloride gas, which coat the fossil in a thin, bright white film. (The powder will later be gently washed off the fossil and has no permanent effect, making it a good option for introducing contrast in fossils.)

The final result is a startlingly white trilobite fossil, with easily discernable bumps and ridges that paleontologists like Hopkins use to identify the species.

Learn many more methods of specimen prep in the new episode of Shelf LifeSix Ways to Prepare a Coelacanth.

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Geology of New England, 1826 #tbt

I was so excited when I found this image that I wasted time I should have been working on an abstract. Oops. This was just too neat.

This is a gigantic geologic cross section of New England drawn about 130 years before the acceptance of plate tectonics. It starts on the left in Boston Harbor and ends in the right at Lake Erie. Some noteable places like Boston, Syracuse, and Utica give context for the cross section.

There’s so much content on here that gives insight to how early geologists viewed this continent – rocks that were gradually folded, single units of shale or greywacke running across half the section, missing faults, but mostly granite/gneiss bodies rising upwards inexplicably to make up the cores of mountain ranges. The Old Red Sandstone, one of the most famous units from Great Britain, even makes an appearance. Today we understand that plate tectonic processes have often caused those igneous cores to be thrust upwards by faults and that some of the igneous rocks west of Boston actually are an accreted island arc terrane.

This file was published last week and made available under a creative commons license from the collections of the New York Public Library. Look closer and see what else you can find.

-JBB

Image credit: The Miriam and Ira D. Wallach Division of Art, Prints and Photographs: Print Collection, The New York Public Library. "Geological profile extending from the Atlantic to Lake Erie." New York Public Library Digital Collections. http://digitalcollections.nypl.org/items/510d47d9-7f0e-a3d9-e040-e00a18064a99

Source: facebook.com
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New Zealand's Mount Tongariro in 2012

On this date in 2012, New Zealand's Mount Tongariro erupted, sending ash clouds high into the air. This is our post that went up at the time - useful both for archive purposes and to see the kinds of actions taken in response to a volcanic eruption close to populated areas.

The ash produced by the eruption, at Te Maari crater, reached a 3 to 4 kilometre height seen from Taupo. Residents reported that the sulphur is the air was making it hard to breathe. The eruption occurred shortly after 1:20pm NZ time (00:20am UTC/GMT) today (November 21) and was the same location as the eruption on August 6, which was the first eruption on Tongariro for more than 100 years (http://on.fb.me/10rrsWP). The earlier eruption widened the crater and reactivated dormant vents. The eruption today did not produce any directed rock blasts or debris flows like those made by the August eruption. There were no precursory features recorded for today’s eruption, but based on the August eruption and the description from the eruptions of the late 1890’s, scientists warn that another eruption of similar size is expected within the next few weeks, though the eruptions are not expected to escalate in size. Up to 90 schoolchildren were on the mountain and two hours into a tramping trip; they are now safe and well. The group were near the Katetahi hot springs when they saw the eruption begin, about one kilometre away from them. They witnessed many tourists running from the eruption (video here: http://bit.ly/S9Xbt7). 30-50 people were evacuated from the Tongariro Crossing track; no injuries were reported and the crossing has now been closed. Scientists have been collecting ash from the eruption to be analysed at Massey University in order to ascertain potential human and animal health effects; results are expected in the next few days. The eruption lasted about five minutes although earthquake activity continued locally for about 15 minutes. The alert level on Tongariro has been upgraded to level 2 by GNS (New Zealand’s Geological and Nuclear Sciences). Alert level 2 means there is minor eruptive activity. Geonet's Alert levels for volcanoes range from 0 (typical background surface activity) through to 5 (hazardous large volcanic eruption in progress). The aviation colour code was upgraded to red, meaning there was a significant emission of ash in the atmosphere. As of 5:30pm NZ time 21 November (4:30am UTC/GMT) the aviation colour code has been downgraded to orange, indicating a volcanic eruption is underway but there is little to no ash being produced. The national airline, Air New Zealand, has cancelled all flights between Taupo and Wellington because of the volcanic activity. The ash is expected to be pushed in an easterly direction and away from the main route that airlines fly across the North Island, as there currently are light south-westerly winds in the region. The ash will most likely be ‘pushed’ towards State Highway 1. NZ’s Civil Defence has issued a national advisory saying regions from Waikato down to Hawke’s Bay could be affected by the ash cloud. Mt Raupehu has also been active recently but has not yet erupted. GNS reported last week that there was pressure building under the volcano and there was an increased likelihood of a volcanic eruption. Recent temperature readings from the volcano indicate that an eruption may occur in the coming weeks. As a result, hikers have been requested to keep off the summit. Scientists have been monitoring a snow melt lake in the crater and have discovered that while the lake is only 20°C, the temperature a few hundred meters beneath the lake is 800°C; this may suggest that volcanic vent is partially blocked and pressure may be building up. Ruapehu is New Zealand’s largest active volcano with historic major eruptions occurring every 20 to 50 years. There was a small eruption in 2007 which propelled a large rock onto the leg of a nearby hiker. The last large eruptions were in 1995 and 1996. Tongariro and Ruapehu are relatively close to each other but scientists report no evidence that the activity at both volcanoes was related. In Maori legend, Ruapehu was a beautiful maid who was married to Taranaki (a volcano near New Plymouth in the North Island of NZ). Ruapehu was wooed away from her husband by Tongariro; Taranaki discovered the affair and fought Tongariro. Taranaki was defeated so retreated towards the west coast, but he now faces towards Ruapehu and Tongariro, watching them silently. Ruapehu still loves her husband and sighs occasionally when she recalls memories of him; Taranaki’s mist which drifts easterly is the visible sign of his lingering love for her. Tongariro is angered by this activity and often smokes and smoulders in a jealous rage. If the region looks familiar, Ruapehu and nearby Mount Ngauruhoe 'starred' as Mount Doom in “Lord of the Rings”. View a timelapse of the most recent Tongariro eruption here (there’s a short ad first): http://www.3news.co.nz/VIDEO-Time-lapse-of-Mt-Tongariro-eruption/tabid/1216/articleID/277560/Default.aspx To see a timelapse of Tongariro National Park during a calmer period: http://www.youtube.com/watch?feature=player_embedded&v=e-fLn-H7wJE. -TEL & Jean http://info.geonet.org.nz/pages/viewpage.action?pageId=3801181; http://www.stuff.co.nz/national/7979461/Tongariro-eruptshttp://www.3news.co.nz/Where-will-the-Tongariro-ash-cloud-go/tabid/1160/articleID/277558/Default.aspx#ixzz2Cq0youWUhttp://www.teara.govt.nz/en/1966/ruapehu-mount/3 Te Maari crater camera: http://www.geonet.org.nz/volcano/info/tongariro/camera/tongarirotemaaricrater Photo: LOMI SCHAUMKEL/Tamatea Intermediate School
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