Showing posts with label Nature. Show all posts
Showing posts with label Nature. Show all posts

Feb 18, 2013

Top 10 Largest Meteor Craters on Earth

impactA meteorite unexpectedly pierced through the atmosphere over the Urals Region in Russia on Friday morning and exploded about 12 to 15 miles above ground, creating a shockwave that damaged houses, shattered windows and injured more than 1,200 people.

According to NASA, the celestial body, which measures 17 meters in diameter and 10,000 tons in weight, crossed the atmosphere at the supersonic speed of 44,000 miles per hour and released a force of 500 kilotons at the time of its explosion, 30 times that of the nuclear bomb dropped on Hiroshima in 1945.

Scientists in Russia are still searching Chelyabinsk for leftover debris.

Usually, a meteor crater will be formed when a meteor impacts another celestial body. A number of meteor craters can be found across the Earth, but few have diameters of 20 kilometers or above. Statistics show that on average the Earth experiences only one to three meteorite falls powerful enough to leave a 20 km diameter crater per million years.

Following are the top 10 largest meteor craters ever recorded in our planet’s 4.6 billion-year-long history. [via: China.org.cn]

 

10. Puchezh-Katunki Crater

Location: Nizhny Novgorod Oblast, Russia

Diameter (km): 80

Age (mln years): 167

Coordinates: 56°58′N 43°43′E

Puchezh-Katunki_crater_Russia_lansatimage source

Puchezh-Katunki is a meteor crater in the Chkalovsky District of Nizhny Novgorod Oblast in Volga Federal District, Russia. It is 80 km (50 mi) in diameter and is estimated to be 167 ± 3 million years old, placing it in the Middle Jurassic. The crater is not exposed to the surface, but appears as variation in the vegetation.

The central dome, ring depression, and ring terrace of the 80 km (50 mi) wide impact structure are nearly completely buried under Neogene and Quaternary sediments, with the only exposed impactites found on the banks of the Volga River. [link]

 

9. Chesapeake Bay Crater

Location: Virginia, United States

Diameter (km): 85

Age (mln years): 35.5

Coordinates: 37°17′N 76°1′W

Chesapeake_Crater_locationLocation of the crater in North America [image source]

The Chesapeake Bay impact crater was formed by a bolide that impacted the eastern shore of North America about 35 million years ago, in the late Eocene epoch. It is one of the best-preserved "wet-target" or marine impact craters, and the largest known impact crater in the U.S. Continued slumping of sediments over the rubble of the crater has helped shape Chesapeake Bay. [link]

 

8. Acraman Crater

Location: South Australia, Australia

Diameter (km): 85-90

Age (mln years): 580

Coordinates: 32°1′S 135°27′E

AcramanLake Acraman (impact crater) in South Australia [image source]

Acraman crater is a deeply eroded impact crater in the Gawler Ranges of South Australia. Its location is marked by Lake Acraman, a circular ephemeral playa lake about 20 km in diameter.

The discovery of the crater and independent discovery of its ejecta were first reported in the journal Science in 1986. The evidence for impact includes the presence of shatter cones and shocked quartz in shattered bedrock on islands within Lake Acraman. [link]

 

7. Popigai Crater

Location: Siberia, Russia

Diameter (km): 100

Age (mln years): 35.7

Coordinates: 71°39′N 111°11′E

Popigai_crater_russiaimage source

The Popigai crater (or astrobleme) in Siberia, Russia is tied with Manicouagan Crater as the seventh largest verified impact crater on Earth. A large bolide impact created the 100 kilometres (62 mi) diameter crater 35.7 ± 0.2 (2σ) million years ago during the late Eocene (Priabonian stage). The crater is 300 km east from the outpost of Khatanga and 880 km (550 mi) NE of the city of Norilsk. It is designated by UNESCO as a Geopark, a site of special geological heritage. [link]

 

6. Manicouagan Crater

Location: Quebec, Canada

Diameter (km): 100

Age (mln years): 215

Coordinates: 51°23′N 68°42′W

Manicouaganimage source

The Manicouagan Crater is one of the oldest known impact craters on Earth and is located primarily in Manicouagan Regional County Municipality in the Côte-Nord region of Québec, Canada, about 300 km (190 mi) north of the city of Baie-Comeau. At roughly 213-215 million years old, Manicouagan is one of the youngest large astroblemes visible on the surface. Its northernmost part is located in Caniapiscau Regional County Municipality. It is thought to have been caused by the impact of a 5 km (3 mi) diameter asteroid about 215.5 million years ago (Triassic Period). It was once thought to be associated with the end-Carnian extinction event.

The crater is a multiple-ring structure about 100 km (60 mi) across, with its 70 km (40 mi) diameter inner ring its most prominent feature; it contains a 70 km (40 mi) diameter annular lake, the Manicouagan Reservoir, surrounding an inner island plateau, René-Levasseur Island. It is the earth's sixth largest confirmed impact crater according to rim-to-rim diameter. [link]

 

5. Kara Crater

Location: Nenetsia, Russia

Diameter (km): 120

Age (mln years): 70.3

Coordinates: 69°6′N 64°9′E

Kara_crateri_crater_Russia_lansatimage source

Kara is a meteor crater in the Yugorsky Peninsula, Nenetsia, Russia.

It is 65 km in diameter and the age is estimated to be 70.3 ± 2.2 million years old (Upper Cretaceous). Impactite outcrops located on the Baydarata Gulf shore north-east of the crater imply that the original size of the crater, now greatly eroded, was 120 km in diameter, making it the 4th largest on earth. The crater is not exposed to the surface. [link]

 

4. Woodleigh Crater

Location: Western Australia, Australia

Diameter (km): 60-160

Age (mln years): 364

Coordinates: 26°3′S 114°40′E

Woodleigh_gravityimage source

Woodleigh is a large meteorite impact crater (astrobleme) in Western Australia, centred on Woodleigh Station east of Shark Bay. A team of four scientists at the Geological Survey of Western Australia and the Australian National University, led by Arthur J. Mory, announced the discovery in the 15 April 2000 issue of Earth and Planetary Science Letters.

The crater is not exposed at the surface and therefore its size is uncertain. The original discovery team believe it may be up to 120 km (75 mi) in diameter, but others argue it may be much smaller, with one study suggesting a diameter closer to 60 km (37 mi). The larger estimate of 120 km, if correct, would make this crater tied for the fourth largest confirmed impact structure in the world, and imply a bolide (asteroid or comet) about 5–6 km (3.1–3.7 mi) in diameter. A more recent study suggest the crater could be between 60 to 160 km or more, and was produced by a comet or asteroid 6 to 12 km wide. [link]

 

3. Chicxulub Crater

Location: Yucatán, Mexico

Diameter (km): 180

Age (mln years): 65

Coordinates: 21°20′N 89°30′W

Yucatan_chix_craterimage source

The Chicxulub crater is a prehistoric impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is located near the town of Chicxulub, after which the crater is named. The age of Chicxulub asteroid impact and the Cretaceous–Paleogene boundary (K–Pg boundary) coincide precisely, leading to the conclusion that the cause of the crater was the same cause resulting in the demise of nonavian dinosaurs on Earth. The crater is more than 180 km (110 mi) in diameter, making the feature one of the largest confirmed impact structures on Earth; the impacting bolide that formed the crater was at least 10 km (6 mi) in diameter. [link]

 

2. Sudbury Basin

Location: Ontario, Canada

Diameter (km): 250

Age (mln years): 1849

Coordinates: 46°36′N 81°11′W

Sudbury_Wanapitei_WorldWindimage source

The Sudbury Basin, also known as Sudbury Structure or the Sudbury Nickel Irruptive, is a major geologic structure in Ontario, Canada. It is the second-largest known impact crater or astrobleme on Earth, as well as one of the oldest.

The basin is located on the Canadian Shield in the city of Greater Sudbury, Ontario. The former municipalities of Rayside-Balfour and Valley East lie within the Sudbury Basin, which is referred to locally as "The Valley". The urban core of the former city of Sudbury lies on the southern outskirts of the basin.

The Sudbury Basin is located near a number of other geological structures, including the Temagami Magnetic Anomaly, the Lake Wanapitei impact crater, the western end of the Ottawa-Bonnechere Graben, and the eastern end of the Great Lakes Tectonic Zone although none of the structures are directly related to each other in the sense of resulting from the same geophysical processes. [link]

 

1. Vredefort Crater

Location: Free State, South Africa

Diameter (km): 300

Age (mln years): 2023

Coordinates: 27°0′S 27°30′E

Vredefort_Dome_STS51I-33-56AAimage source

Vredefort crater is the largest verified impact crater to have existed on Earth, more than 300 km across. It was located in the present-day Free State Province of South Africa and named after the town of Vredefort, which is situated near its centre. While the crater itself has long since eroded away, remaining geological structures at its centre are known as the Vredefort Dome or Vredefort impact structure. In 2005, the Vredefort Dome was added to the list of UNESCO World Heritage Sites for its geologic interest. [link]

Sep 25, 2011

The World's Most Beautiful Glaciers

Panorama of Perito Moreno Glacier

Global warming threatens glaciers. In the news time from time slips that one or another icy river is endangered. So the best way is to hurry in order to make sure that the photos do not lie, and the ice really is all shades of blue and pink colors, and not white, as it appears to those who saw it only in the form of icicles, hanging from the roofs of houses.

Aug 22, 2011

9 of the Most Impressive Balanced Stones in the World

balanced_rocks_00Earth may be one of the most geologically active planets in the solar system, but don’t tell that to these 9 brazenly oblivious balanced stones.

Poised between inertial stability and the relentless force of gravity, these rock-steady rocks maintain a precarious balance between soil and sky.

Aug 4, 2011

White Sands National Monument: The World's Largest Gypsum Dune Field

White_Sands_National_Monument_01Located at the northern end of the Chihuahuan Desert of Southern New Mexico, lies the amazing national treasure known as the White Sands National Monument. Within this national monument you will find the largest concentration of white pristine gypsum sand in the world.

This almost snow-like-sand is produced by the Tularosa Basin. The basin was formed by the collapse of a dome made up of the gypsum sand. The collapse occurred about ten million years ago and what remains of the sides of the original dome are what we now call the San Andreas and Sacramento Mountain ranges.

May 17, 2011

World’s Biggest Meteorite Craters

Meteor_resize An impact crater forms when an asteroid or comet strikes another body such as an asteroid, planet, or moon at high speed. As Earth is so active geologically, most traces of impact craters have been erased by erosion and tectonic activity. Nevertheless, over one hundred seventy impact craters have been identified on Earth.

Here are some of the biggest Meteorite craters found on earth. I hope you will like it.

Apr 19, 2011

The Most Famous And Scary Devil Tower

The-Most-Famous-And-Scary-Devil-Tower-01 One of the most famous and most mysterious places on our planet who adore travelers - a rock Devils Tower, located in the reserve in northeast Wyoming in the U.S..

Let's start with the fact that the Devils Tower or Devil's Tower - not only the name of this rock. With its other name is connected one of the Indian legend of the seven local girls who were walking in the woods when they threw a huge and ferocious bear. Girls long fled from the infuriated animal, but the bear would not leave. In desperation, the children climbed on a simple stone and prayed for the salvation of the Great Spirit.

Mar 28, 2011

The Mysterious Nazca Lines (10 amazing pics)

Nazca_monkey The Nazca Lines are a series of ancient geoglyphs located in the Nazca Desert in southern Peru. They were designated a UNESCO World Heritage Site in 1994. The high, arid plateau stretches more than 80 kilometres (50 mi) between the towns of Nazca and Palpa on the Pampas de Jumana about 400 km south of Lima. Although some local geoglyphs resemble Paracas motifs, scholars believe the Nazca Lines were created by the Nazca culture between 400 and 650 CE. The hundreds of individual figures range in complexity from simple lines to stylized hummingbirds, spiders, monkeys, fish, sharks, orcas, llamas, and lizards.

Mar 21, 2011

‘Supermoon’ Phenomenon: The Largest Full Moon In More Than 18 Years

supermoon03 The largest full moon in more than 18 years – a so-called "supermoon" – did not disappoint eager skywatchers around the world Saturday when it rose, big and bright, into Earth's night sky.

The full moon of March was 221,565 miles (356,575 kilometers) on Saturday, March 19 just 50 minutes after it hit its full phase, making it the biggest and brightest full moon since 1993. The "supermoon" phenomenon occurred because the moon was in its full phase and just 50 minutes past perigee – the point of its orbit that brings it closer to Earth. (source: space.com)

Jan 5, 2011

World’s Largest Cave: The Son Doong (Found in Vietnam)

largest-vietnam-cave A massive cave recently uncovered in a remote Vietnamese jungle is the largest single cave passage yet found, a new survey shows.

At 262-by-262 feet (80-by-80 meters) in most places, the Son Doong cave beats out the previous world-record holder, Deer Cave in the Malaysian section of the island of Borneo.

Dec 19, 2010

Top 10 Most Dangerous Waves in the World

teahupoo1 With super advanced equipment, tow-in access, and internet swell tracking, a growing number of surfers are getting rides on incredibly powerful waves.

What makes a wave dangerous? Is sheer size an accurate indicator for how hazardous a surf spot is? Read on for our roundup of the top ten most dangerous waves in the world.

Oct 14, 2010

World’s Largest Snow Drawing

world’s largest snow drawing logo

These odd circles may look like messages from aliens or the humorous graffiti of penguins, but it’s actually the ephemeral snow and ice art of earth artist Jim Denevan, best known for his temporary beach masterpieces. The snow circles are somewhat of a departure from Denevan’s usual medium, but he’s no stranger to large-scale natural art. This nine-square-mile snow drawing currently holds the record as the world’s largest snow drawing; the record before that belonged to a sand drawing created in the Nevada desert by Denevan.

Aug 2, 2010

The World's Best Nude Beaches - Top 10 List

The long-awaited sequel to New York Times bestseller The World Guide to Nud* Beaches and Resorts. This guide unveils the top 1,000 places where bare skin is simply the most fashionable thing to wear. More than 50 countries are explored in depth, including the US and Canada, the Caribbean, France, Spain, Italy, Greece, Portugal, Croatia, the UK, Germany, the Netherlands, Scandinavia, Australia, New Zealand and Latin America. Don't get undressed without it! – The World's Biggests Choice!

Feb 1, 2010

Greenland - World's Largest Island

Greenland  is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically associated with Europe (specifically Denmark-Norway) for about a millennium.

In 1979, Denmark granted home rule to Greenland, with a relationship known in Danish as Rigsfællesskabet, and in 2008 Greenland voted to transfer more competencies to the local government. This became effective the following year, with the Danish royal government remaining in charge only of foreign affairs, security and financial policy, and providing a subsidy of DKK 3.4 billion ($633m), or approximately US$11,300 per Greenlander, annually.

Greenland is, by area, the world's largest island that is not a continent. It is the least densely populated country in the world.

The bedrock in the center of Greenland has been pressed below sea level by the weight of the ice sheet. Thus, if the ice suddenly melted, much of central Greenland would be under water.

Geography of Greenland

Greenland, the largest island in the world, is located between the Arctic Ocean and the North Atlantic Ocean, northeast of Canada and northwest of Iceland. Greenland has no land boundaries and 44,087 km of coastline. A sparse population is confined to small settlements along the coast. Greenland possesses the world's second largest ice sheet.

The vegetation is generally sparse, with the only patch of forested land being found in Nanortalik Municipality in the extreme south near Cape Farewell.

The climate is arctic to subarctic with cool summers and cold winters. The terrain is mostly a flat but gradually sloping icecap that covers all land except for a narrow, mountainous, barren, rocky coast. The lowest elevation is sea level and the highest elevation is the summit of Gunnbjørn Fjeld, the highest point in the Arctic at 3,694 meters (12,120 ft). The northernmost point of the Island of Greenland is Cape Morris Jesup, discovered by Admiral Robert Peary in 1909. Natural resources include zinc, lead, iron ore, coal, molybdenum, gold, platinum, uranium, fish, seals, and whales.

Area

Total: 2,175,600 km²
Land: 2,175,600 km² (341,700 km² ice-free, 1,833,900 km² ice-covered) (est.)

Maritime claims:
exclusive fishing zone: 200 nautical miles
territorial sea: 3 nautical miles


Source: 1, 2

Jan 21, 2010

Mammoth Cave - World's Longest Cave

Mammoth Cave National Park is a U.S. National Park in central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. The official name of the system is the Mammoth-Flint Ridge Cave System for the ridge under which the cave has formed. The park was established as a national park on July 1, 1941. It became a World Heritage Site on October 27, 1981, and an international Biosphere Reserve on September 26, 1990.

The park's 52,835 acres (21,382 ha) are located primarily in Edmonson County, Kentucky, with small areas extending eastward into Hart County and Barren County. It is centered around the Green River, with a tributary, the Nolin River, feeding into the Green just inside the park. With a confirmed 365 miles of passageways it is by far the world's longest known cave system, being well over twice as long as the second longest cave system, which is South Dakota's Jewel Cave with 145 miles of passageways.

Mammoth Cave developed in thick Mississippian-aged limestone strata capped by a layer of sandstone, making the system remarkably stable. It is known to include more than 360 miles (580 km) of passageway; new discoveries and connections add several miles to this figure each year. Mammoth Cave National Park was established to preserve the cave system.

The National Park Service offers several cave tours to visitors. Many of the most famous features of the cave, such as Grand Avenue, Frozen Niagara, and Fat Man's Misery, can be seen on lighted tours ranging from one to six hours in length. Two tours, lit only by visitor-carried paraffin lamps, are popular alternatives to the electric-lit routes. Several "wild" tours venture away from the developed parts of the cave into muddy crawls and dusty tunnels.



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Jan 16, 2010

World's Largest Gorge - The Grand Canyon of the Colorado River

The Grand Canyon (Spanish: Gran Cañón) is a steep-sided gorge carved by the Colorado River in the United States in the state of Arizona. It is largely contained within the Grand Canyon National Park, one of the first national parks in the United States. President Theodore Roosevelt was a major proponent of preservation of the Grand Canyon area, and visited it on numerous occasions to hunt and enjoy the scenery.

The Grand Canyon is 277 miles (446 km) long, ranges in width from 4 to 18 miles (6.4 to 29 km) and attains a depth of over a mile (1.83 km) (6000 feet). Nearly two billion years of the Earth's geological history have been exposed as the Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau was uplifted. While the specific geologic processes and timing that formed the Grand Canyon are the subject of debate by geologists, recent evidence suggests the Colorado River established its course through the canyon at least 17 million years ago. Since that time, the Colorado River continued to erode and form the canyon to the point we see it as today.



Before European immigration, the area was inhabited by Native Americans who built settlements within the canyon and its many caves. The Pueblo people considered the Grand Canyon ("Ongtupqa" in Hopi language) a holy site and made pilgrimages to it. The first European known to have viewed the Grand Canyon was García López de Cárdenas from Spain, who arrived in 1540.


The Grand Canyon is a massive rift in the Colorado Plateau that exposes uplifted Proterozoic and Paleozoic strata, and is also one of the six distinct physiographic sections of the Colorado Plateau province. It is not the deepest canyon in the world; Kali Gandaki Gorge in Nepal is far deeper, nor the widest (Capertee Valley in Australia is about 1 km wider and longer than Grand Canyon) — but the Grand Canyon is known for its visually overwhelming size and its intricate and colorful landscape. Geologically it is significant because of the thick sequence of ancient rocks that are beautifully preserved and exposed in the walls of the canyon. These rock layers record much of the early geologic history of the North American continent.



Uplift associated with mountain building events later moved these sediments thousands of feet upward and created the Colorado Plateau. The higher elevation has also resulted in greater precipitation in the Colorado River drainage area, but not enough to change the Grand Canyon area from being semi-arid. The uplift of the Colorado Plateau is uneven, and the north-south trending Kaibab Plateau that Grand Canyon bisects is over a thousand feet higher at the North Rim (about 1,000 ft/300 m) than at the South Rim. Almost all runoff from the North Rim (which also gets more rain and snow) flows toward the Grand Canyon, while much of the runoff on the plateau behind the South Rim flows away from the canyon (following the general tilt). The result is deeper and longer tributary washes and canyons on the north side and shorter and steeper side canyons on the south side.



Temperatures on the North Rim are generally lower than the South Rim because of the greater elevation (averaging 8,000 ft/2,438 m above sea level). Heavy rains are common on both rims during the summer months. Access to the North Rim via the primary route leading to the canyon (State Route 67) is limited during the winter season due to road closures. Views from the North Rim tend to give a better impression of the expanse of the canyon than those from the South Rim.



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