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---------------------------- 2756 - METEOR - Chicxulup Mexico meteor?
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- On one of our Mexico vacations we visited the Yucatan and were awed by the flat land expanse down to the sea. Then, there were these massive volcanic holes in the earth. Many were filled with water and open for leisure swimming.
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- Some 70,000,000 years ago the entire peninsula was affected by the Chicxulub impact event that was an enormous catastrophe that left a huge imprint on the Earth’s surface. Not only did it cause the mass extinction of the dinosaurs, it left a crater 112 miles in diameter, and deposited a worldwide layer of concentrated iridium in the Earth’s crust.
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- A new study shows that the impact also left its mark deep underground, in the form of a vast hydrothermal system that modified a massive chunk of the Earth’s crust. The Chicxulub impact was catastrophic for life on Earth. When that huge comet, or asteroid, or meteor, struck Earth, it set in motion a chain of events that changed the history of the planet.
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- The impact penetrated about 12 miles into the Earth’s crust. It created a massive tsunami, ignited fires around the globe, and sent massive amounts of material into the atmosphere. Due to the carbon-rich and sulfur-rich nature of the impact site, the atmosphere became clogged with stratospheric soot and sulfate aerosols.
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- Those materials persisted in the atmosphere, stifling photosynthesis and creating a global cooling that wiped out about 75% of Earth’s species, including all the non-avian dinosaurs. “Non-avian” were those that could not fly.
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- Hidden out of sight, deep underground, is a vast hydrothermal system created by the impact. The nature of that system is only now coming to light. A new study presents the details of this underground system.
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- The Chicxulub crater is the most well-preserved large impact structure on Earth. It’s been studied extensively. In 2016 a team of researchers studied deep core samples of the ocean floor at the impact site, gathered by a drilling rig. Some of those samples came from 4,380 ft. beneath the sea floor.
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- That research showed how Chicxulub’s peak ring was formed, and showed the displacement of rocks, where deeper granite bedrock was placed above sedimentary rocks by the energy of the impact.
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- New work focused on the chemical and thermal modification of the rock at the impact site. The study deduced that the Chicxulub impact event created a vast underground hydrothermal system, larger than the Yellowstone Caldera, that was active for over 150,000 years.
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- Some impact craters, including Chicxulub, create a peak ring. It’s a raised range of mountains inside the crater rim. The peak rings are uplifted by the rebound force of the impact, and they’re made of fractured rock.
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- The rock in Chicxulub’s case is granite, lifted from a depth of 6 miles in the Earth’s crust. The force of the impact and the uplifting caused the fracturing. That peak ring is further covered with impact debris, itself fractured and permeable, and both the surface debris and the uplifted crust were subjected to the effects of the hydrothermal system.
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- The researchers found evidence of underground rivers of water that were superheated by the impact, and driven upwards. Those subterranean rivers met with the boundary between the impact crater’s floor and the bottom of the ocean. There, the heated water met a 1.8 mile pool of magma created by the impact, called the central melt pool. The water couldn’t penetrate that magma, and was forced around its edges. Then it percolated through all of the fractured rock, and was vented into the sea.
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- The hot water activity was particularly intense near the crater’s peak ring. The peak ring is 56 miles in diameter. The team examined rock samples from that ring and found that the ring is riveted with fossilized hydrothermal conduits. As the super-heated water flowed through these conduits 66 million years ago, it left its mark. The water deposited almost two dozen different types of minerals on the walls of these conduits, replacing the original minerals.
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- Hot-fluid alteration was most vigorous in the permeable impact debris, but garnet crystals, indicating high temperatures, were found at different levels throughout the core. These minerals appear to have recorded changes in the Earth’s magnetic field as they formed.”
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- The types of minerals told the researchers a lot about the hydrothermal system. The temperature of the water had to be 570 to 750 F. That much thermal energy would’ve taken a long time to dissipate, so high temperatures must have persisted for a long time. The researchers used the magnetic polarity of the minerals to create a kind of “geomagnetic polarity clock” that measures the cooling time.
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- Results of the study indicate that tiny magnetic minerals were created in the Chicxulub crater due to chemical reactions produced by a long-lived hydrothermal system. These minerals appear to have recorded changes in the Earth’s magnetic field as they formed. Their magnetic memories suggest that hydrothermal activity within the crater persisted for at least 150,000 years.
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- Previous research into Chicxulub allowed scientists to develop a hydrothermal evolution model. This new study tested that model with a borehole into the peak ring 25 miles from the crater center. Temperature decreases with distance but is still 300°C at the point corresponding to the base of the borehole.
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- There’s also ocean sediment at the impact site that’s unusually rich in manganese. The researchers point out that that’s also evidence of a long-lived hydrothermal system.
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- Similar to mid-ocean ridges, venting from marine impact craters generates hydrothermal plumes that contain dissolved and slowly oxidizing manganese, which compared to background concentrations produced enrichments up to ten-fold in post-impact sediments over 2.1 million years at Chicxulub.
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- There was an approximately 185 mile-long string of hot water vents on the peak ring and additional vents scattered across the crater floor as impact melt cooled. Importantly, such hydrothermal systems may have provided habitats for microbial life.
The hydrothermal system created a network of porous, permeable niches perfect for microbial ecosystems.
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- Research into extremophiles has opened our eyes to the potential for life to thrive in, and even arise from, extreme environments. This is where the comparison between the Yellowstone Caldera and the Chicxulub hydrothermal system play a role.
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- The Yellowstone hydrothermal system contains abundant microbial life. And though the Yellowstone system was created volcanically, while the Chicxulub system was created by impact, the pair of systems are similar, and contain the same biological potential for life.
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- The study of the expedition’s rock core from a potential deep Earth habitat provides additional evidence for the impact-origin of life hypothesis. Life may have evolved in an impact crater.
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- The discovery of this massive and long-lived hydrothermal system could change our understanding of how life came to be on Earth. Scientists know that there’ve been thousands of similar impacts in Earth’s deep geological history. The hydrothermal systems they created may have provided the niche footholds that gave life a chance to get going.
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- The hydrothermally core demonstrates that impact cratering is a fundamentally important heat engine in emerging planetary systems and that the geologically young Chicxulub crater is a suitable analog for terrestrial impact basins created almost 4,000,000,000 years ago.
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- Impact-generated hydrothermal systems were prominent features on early Earth and wherever water exists in a planetary crust. This model is transferrable to an early Mars and any exoplanetary system with similar conditions.
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- Maybe we should be looking for exoplanets with ancient impact craters if we want to find life. It is hard to believe that we were swimming in one of these impact craters. All signs of dinosaurs had long evaporated.
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-------------------------------------- Other reviews about meteors:
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- 2633 - METEORS - we call them shooting stars. How four small pieces of rock can teach us about the history of the solar system. The first is a meteor from outer space that hurtled through the atmosphere of a bright, blue planet to land upon a world populated by strange, multi-tentacled creatures.
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- 2586 METEORITE - the oldest meteorite? A meteorite that crashed into rural southeastern Australia in a fireball in 1969 contained the oldest material ever found on Earth, stardust that predated the formation of our solar system by billions of years
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- 2389 - METEORS - we call them shooting stars. Shooting Stars are meteoroids that enter Earth’s atmosphere in the night sky. On average on a dark night you can see a shooting star once an hour. These meteoroids are rocky dust and debris zipping around our solar system at 30,000 mph.
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- 2343- The Story of a Rock A meteorite rock was found in Oman, Africa in September, 2002. The rock tells us that it came from the Moon and it even tells us which crater on the Moon it was ejected from. About 30 Earth rocks have been found and identified as originating on the Moon. This is the story of two of these rocks. The first rock was found in Oman. a country southeast of Saudi, Arabia on the Arabian Peninsula.
1619 - How often do meteors hit Earth and how big are they? What were the more famous meteors that impacted Earth. What is the likelihood another big one is on its way?
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- 1611 - Meteor Impacts. How many meteors of all types hit us each year? When is the next big hit expected? Learn the equations that give the answers.
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- 1567 - The Russian Meteor - The Russian Meteor. Valentine’s Day was a real surprise for many people in Russia. February 14, 2013, a 10,000 ton meteor blasted through the atmosphere. The fireball was traveling 40,000 miles per hour. The shockwave created when the meteor hit the atmosphere blew out glass windows in over 3,000 buildings, over a 1,000 square kilometers. Over 1,000 people were injured. Mostly glass cuts, one with a broken back. People instinctively went to the windows to see what caused the giant flash of light. They were standing in front of the windows when the shockwave reached them.
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- 1557 - Tektites in Healdsburg, California - January 23, 2013, our local paper ran an article about the tektites found in Dry Creek Valley around Healdsburg, California, just 20 miles from my house. What in the world are tektites?
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- 1019 - The Sudbury Asteroid. A giant asteroid struck Earth 1,850,000,000 years ago creating the Sudbury Basin in Ontario, Canada. The impact blew a crater in the shallow sea floor that was 160 miles across. Along the seashore were dense colonies of cyan bacteria. Their stumpy masses are call stromatolites.
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- 1017 - Meteorite and Asteroids. Meteorites have been landing on the surface of Earth for millions of years. We have found many of them. You can buy them on E-Bay. In 2004 in Placid, Florida a 5.3 pound asteroid was recovered. E-bay says it came from the planet Mercury so it would yield a higher price. But, astronomers do not think it came from Mercury. They believe it came from the Asteroid Belt.
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- 719 - Geminid Meteor Shower. December 14, 2006, is the peak of the Geminid meteor shower in the night sky. A meteor is a streak of light, often called a shooting star. We see the light trailing a meteoroid. A meteoroid is an interplanetary object that is bigger than a speck of dust and smaller than an asteroid.
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- June 6, 2020 2756
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