Antarctica – ontdekkingen dat een andere kijk op geschiedenis geven

Home Tijdlijnen (forum) Kennis delen Antarctica – ontdekkingen dat een andere kijk op geschiedenis geven

  • Dit onderwerp bevat 4 reacties, 1 deelnemer, en is laatst geüpdatet op 26 juni 2022 at 17:10 door Anna Krasko.
Weergave van 4 reactie threads
  • Auteur
    Berichten
    • #9330
      Anna Krasko
      @akrasko97

      Hidden Beneath The Ice of Antarctica… Lost Civilization of the Pre-Adamites
      Source: https://youtu.be/sFQMFZMBrMM?t=118  (30:20)

      Ancient Civilization Season 3: Free World Premiere Screening –

      Could recently melted snow caps reveal an alternative history of Earth? Explore forgotten ruins and new scientific research that may indicate the presence of a pre-Adamite civilization with advanced architecture, hidden beneath the ice. Plus, see how the mathematical codes revealed by these findings may unlock the mysterious origins of elongated skulls found in sacred resting places across the world.

    • #9331
      Anna Krasko
      @akrasko97

      Antarctica Was Once Covered in Forests. We Just Found One That Fossilized.

      The ancient trees were able to withstand alternating months of pure sunlight and darkness, before falling in history’s greatest mass extinction.

      BY BYELAINA ZACHOS – PUBLISHED NOVEMBER 15, 2017

      Source: Ancient Fossil Forest Discovered in Antarctica, 260 Million Years Old (nationalgeographic.com)

       

      260-Million-Year-Old Fossil Forest Discovered in … Antarctica https://t.co/0qzicFUvX0 pic.twitter.com/wofXuUaW6J

      — Scitech☄️ (@scitecho) November 15, 2017

       

      It was summer in Antarctica, and Erik Gulbranson and John Isbell were on the hunt.

      Bundled up in parkas to brave negative temperatures, fierce winds, and blinding days of 24-hour sunlight, Gulbranson, Isbell, and an international team of researchers searched for fossil fragments. Between November 2016 and January 2017, they scaled the snow-capped slopes of the McIntyre Promontory high above the ice fields and glaciers, sifting through the Transantarctic Mountain’s gray sedimentary rocks for clues. By the end of the expedition, they had uncovered 13 fossil fragments from trees dating back more than 260 million years, around the time of the world’s greatest mass extinction event.

      The fossil discovery hints at the coldest, driest continent’s green and forested past. (Read more about a green snap in Antarctica’s history.)

      A Green History

      “The continent as a whole was much warmer and more humid than it currently is today,” says Gulbranson, a professor at University of Wisconsin – Milwaukee. The landscape would have been densely forested with a low-diversity network of resilient plants that could withstand polar extremes, like the boreal forest in present-day Siberia.

      “Oddly enough, these field sites would have actually been very close to what their current latitude is,” he adds.

      The fossils preserved the biology and chemistry of the ancient trees, which will help the researchers investigate more on these high-latitude ecosystems to figure out how some plants survived the extinction event, and why others didn’t. What’s more, fossil microorganisms and fungi have been preserved inside the wood.

      The specimens look similar to the petrified forests in Yellowstone National Park, which were fossilized when volcanic materials buried the living trees.

      “They’re actually some of the best-preserved fossil plants in the world,” Gulbranson says. “The fungi in the wood itself were probably mineralized and turned into stone within a matter of weeks, in some cases probably while the tree was still alive. These things happened incredibly rapidly. You could have witnessed it firsthand if you were there.”

      The researchers found the prehistoric plants could transition rapidly between seasons, perhaps within the span of a month. Whereas modern plants take months to transition and conserve water differently depending on the time of day, the ancient trees could fluctuate quickly between pitch black winters and perpetually sunny summers.

      “Somehow these plants were able to survive not only four to five months of complete darkness, but also four to five months of continuous light,” Gulbranson says. “We don’t fully understand how they were able to cope with these conditions, just that they did.”

      Mass Extinction

      The Permian period, dating between 299 to 251 million years ago, is marked by the emergence of the supercontinent Gondwana. As a mash of continents, environmental extremes plagued the giant land mass, which included parts of modern-day Antarctica, South America, Africa, India, Australia, and the Arabian Peninsula. Ice caps dominated most of the south and tossed it between ceaselessly sunny summers and pitch-black winters, while the north suffered intense heat and seasonal fluctuations.

      Prehistoric creatures learned to adapt to the turbulent climate until the Permian extinction, which Gulbranson says was most likely caused by volcanism in present-day Siberia. The event wiped out more than 90 percent of marine species and 70 percent of land animals, later making the way for dinosaurs.

      Looking Forward

      The team is planning to continue research in Antarctica by revisiting the continent in the coming weeks. John Isbell and other researchers are already making their way down, and Gulbranson will join them at the polar locale November 23.

      “It’s certainly still a raw and challenging place to try to be as a human being,” Gulbranson says.

    • #9332
      Anna Krasko
      @akrasko97

      NASA discovers two lakes under a layer of ice in Antarctica, part of mysterious network of water (juli 2021)

      Source: NASA discovers two lakes under a layer of ice in Antarctica, part of mysterious network of water – PressWire18

      antarctica
      NASA scientists have found two new lakes under the icy layer in Antarctica. These lakes are part of a network of 1.2 to 2.5 miles beneath the ice. These lakes are said to fill and empty continuously. Because of this, the movement of layers is also affected and also on how water gets into the Southern Ocean. This is an important process of circulation in the world’s oceans.

      water under a layer of ice
      According to Professor Matthew Seyfried, a geophysicist at the Colorado School of Mines and the author of the study, it is not just the ice layer here but the water system that is connected to the Earth’s system. This system under ice was first discovered in 2003 by NASA’s ICESat mission. The data analysis found that the increase in ice in West Antarctica reveals the mass of water beneath the icy layer.

      Color changing snow, fast melting glacier, alarm bells!

      water network
      Earlier it was believed that such lakes flow separately and are not connected with others. Later in 2007, researchers found that changes in the height of the ice on the surface of Antarctica reflect the waters of the lakes below. They empty and then fill up several times before flowing into the Southern Ocean. After the ICESat mission, ICESat-2 helps to understand this network better.

      ice is melting
      Earlier in the second study, scientists have warned that every year 53 thousand square km of ice is melting from the earth. Due to this, humans may have to face serious consequences in the coming time. He said that between 1979 and 2016, so much ice has melted that it can fill the huge Superior Lake.

      ‘Life’ ocean of 3 billion people of the world, will Mumbai drown?
      Ice is melting in Antarctica
      .

      https://navbharattimes.indiatimes.com/photo/msid-84497178,imgsize-853264/pic.jpg

    • #9333
      Anna Krasko
      @akrasko97

      Verdere studies over grote meren onder het ijs van Antarctica vertellen ook, dat het om een dynamische processen gaat van het vullen van meren en lossen van het water in de oceaan. In onderstaande fragment geven ze iets meer details hoe zulke onderzoeken verlopen en wat de bevindingen op dit moment zijn. Bijzonder was om te lezen, dat een van de meren heeft een enorme watervoorraad in de oceaan geloosd in slechts 3 dagen tijd.

      NASA uncovers hidden system of mysteriously draining lakes under Antarctica  The lakes grow and shrink beneath the ice.
      By Stephanie Pappas published July 13, 2021

      Source: NASA uncovers hidden system of mysteriously draining lakes under Antarctica | Live Science

      <…>

      Hidden water

      The lakes sit at the bottom of the ice sheet, where the ice meets the rocky Antarctic continent. Unlike in Greenland, where meltwater flows from the ice surface through crevasses and holes called moulins, Antarctica’s lakes form from beneath the ice, probably as a result of pressure, friction and perhaps geothermal heat.

      This water system was largely invisible until the advent of NASA’s ICESat mission in 2003. The ICESat satellite used lasers to precisely measure the elevation of Antarctic ice. In 2007, Scripps Institution of Oceanography glaciologist Helen Amanda Fricker connected the elevation changes measured by ICESat to the dynamics of the lakes deep beneath the ice surface. As the lakes drain and fill, the ice above rises and falls, offering hints as to what’s happening below.

      Fricker’s breakthrough opened up the possibility of tracking the lake system over time. ICESat, however, collected data for only six years. Its European Space Agency equivalent, CryoSat-2, collected similar data starting in 2010 but over a broader area and with less precision. In September 2018, NASA launched a new satellite, ICESat-2, which collects the highest-precision data yet.

      “ICESat-2 is like putting on your glasses after using ICESat: The data are such high precision that we can really start to map out the lake boundaries on the surface,” Siegfried said.

      A dynamic system

      In the new study, Siegfried and Fricker combined data from ICESat, CryoSat-2 and ICESat-2 to trace changes in the subglacial lake system from October 2003 to July 2020. They focused on three areas with good satellite coverage and known active lakes: the boundary between the Mercer and Whillans ice streams in West Antarctica; the lower MacAyeal Ice Stream, also in West Antarctica; and the upper Academy Glacier in East Antarctica.

      At the Mercer and Whillans boundary, the researchers found two new lakes, which they dubbed the Lower Conway Subglacial Lake and the Lower Mercer Subglacial Lake. They also found that what was thought to be one lake under the MacAyeal ice stream was actually two.

      Over time, these lakes experienced major change. The lakes beneath the Mercer and Whillans ice stream boundary are currently undergoing their third period of drainage in 17 years. Meanwhile, all of the lakes beneath the MacAyeal ice stream have followed their own patterns of draining and filling. The lowermost lake went through four fill-drain events during the study period, each taking only about a year to complete. The second lake drained between 2014 and 2015 and is currently filling up again, while the third lake drained just slightly between 2016 and 2017. Meanwhile, the lakes beneath Academy Glacier drained between 2009 and 2018.

      All of these changes are puzzle pieces in scientists’ understanding of the speed and direction of Antarctica’s ice sheet flow. Already, researchers are finding the links between the under-ice lakes and the ocean: In January, a study co-authored by Fricker found that the drainage of one lake on the Amery Ice Shelf in East Antarctica flushed as much as 198 billion gallons (750 billion liters) into the ocean in only three days, Live Science reported at the time.

      The new study was published July 7 in the journal Geophysical Research Letters.

      Originally published on Live Science

       

    • #9334
      Anna Krasko
      @akrasko97

      Antarctica zonder ijs - vivid maps

       

      Vivid Maps Antarctica under the ice – Vivid Maps

      • Deze reactie is gewijzigd 1 maand, 3 weken geleden door Anna Krasko.
Weergave van 4 reactie threads
  • Je moet ingelogd zijn om een antwoord op dit onderwerp te kunnen geven.

Home Tijdlijnen (forum) Kennis delen Antarctica – ontdekkingen dat een andere kijk op geschiedenis geven