Section of FTO Pakistan website hacked - geo.tv

Section of FTO Pakistan website hacked - geo.tv

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CCTV FOOTAGE OF PC PESHAWAR BOMB BLAST RELEASED

11 killed in PC Peshawar bombing


PESHAWAR: At least 11 persons, including foreigners, were killed and over 50 others injured when a huge blast ripped through the city’s lone five-star Pearl Continental Hotel — adjoining the residence of the corps commander Peshawar — after an exchange of heavy fire between the terrorists and security personnel on Tuesday night.

A senior police official did not confirm whether it was a suicide attack or the Shahzor mini-truck already parked in the parking lot was blown up by remote control. Those sustaining injuries included ANP’s provincial minister Zarshed Khan, Senator Nabi Bangash, UN officials, three foreigners and an airline’s crew.

A large number of vehicles parked in the parking bay, a mosque, shops inside the hotel, banks and other outlets were completely destroyed and others were partially damaged in the explosion at around 10:20 pm.

Heavy firing took place between the hotel’s security staff and the attackers at the entrance before the latter succeeded to take one of the two cars that they were travelling in towards the mosque in the parking lot of the five-star hotel.

The parking lot is located on the right corner of the main PC building that shares a boundary wall with the official residence of the corps commander Peshawar. The hotel administration had received a number of threats from unknown militants in the recent past for hosting foreigners.

“Immediately after the heavy firing, a huge explosion rocked the entire city, destroying a large part of the well-constructed building. For several minutes, no one was able to see anything due to the thick smoke and dust,” said Nadeem Ilahi Malik, a trader. Another eyewitness, Ziauddin, said everybody just ran out of the building once the dust had settled.

The explosion was heard across the city and even in other towns while the thick smoke billowing from the building was seen from miles away despite the darkness. The windowpanes of buildings located several kilometres away too were smashed. The District Coordination Officer (DCO) Peshawar, Sahibzada Mohammad Anis, put the death toll at five, saying 40 other sustained injuries.

There were reports that three of those killed in the blast were foreigners, including a Russian Alexander Joseph. However, none of the officials confirmed the news, saying some foreigners were among the wounded.

Bomb disposal squad (BDS) officials said the intensity of the blast was equal to that of the Marriott Hotel attack in the federal capital. “Around 500 kilograms of explosives was used in the attack that created a 15-foot wide and six-foot deep crater,” said a BDS official.

“We have cleared all the rooms. Those who sustained injuries were taken to the Lady Reading Hospital and also included foreigners,” Capital City Police Officer (CCPO) Safwat Ghayyur told reporters. The city police chief asked media persons to stay away from the building to avoid casualties in case of sliding.

“We are in a war-like situation and I am sure we will succeed in our aims,” opined NWFP Senior Minister Bashir Ahmad Bilour. Provincial Information Minister Mian Iftikhar said the government was not afraid of such attacks.

The PC is located on the main Khyber Road close to the NWFP Assembly building, the Peshawar High Court, residences of the Corps Commander, the Commandant FC, the Golf Club, the district courts building and the secretariat and directorates of different departments.

Strict security measures were taken at the PC following threats. Electrical barricades were installed at the entrance not to allow any vehicle to enter the hotel without proper checking and clearance by the security officials. There were also reports of shifting diplomatic missions to the hotel permanently in the wake of the worsening law and order situation and threats to foreigners.

Rescue work was going on at the site of the blast till the filing of this report. Darkness still prevailed due to destruction of power installations. The headlights of the vehicles were being used to search for bodies and the wounded people under the debris.

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Genes key to hepatitis C 'self-recovery'

In a new study, researchers at Johns Hopkins have found that genes involved in suppressing the body's defensive ''killer'' immune cells are a potential key factor in spontaneous recovery from hepatitis C. The viral infection of the liver can lead to cirrhosis, cancer and even death. This genetic factor was found in people assumed to be exposed to a low dose of virus at the time of infection. ''Our findings may help explain why some of the 20 percent of people infected with hepatitis C manage to recover on their own, while the remaining 80 percent remain infected and may need treatment.'' From Johns Hopkins :
''SELF-RECOVERY'' FROM HEPATITIS C INFECTION LINKED TO GENES THAT SUPPRESS ACTION OF KILLER IMMUNE CELLS

In a study to be published in Science online Aug. 6, researchers at Johns Hopkins have found that genes involved in suppressing the body's defensive ''killer'' immune cells are a potential key factor in spontaneous recovery from hepatitis C. The viral infection of the liver can lead to cirrhosis, cancer and even death. This genetic factor was found in people assumed to be exposed to a low dose of virus at the time of infection.

''Our findings may help explain why some of the 20 percent of people infected with hepatitis C manage to recover on their own, while the remaining 80 percent remain infected and may need treatment,'' said one of the study's lead authors, infectious disease specialist Chloe Thio, M.D., assistant professor of medicine at The Johns Hopkins University School of Medicine.

In determining how some patients self-recover, the scientists hope one day to develop a vaccine and improve therapies for hepatitis C.

''Hepatitis C infection is a serious disease with few treatments, and it takes a heavy toll among disadvantaged Americans, including those who have weakened immune systems and are HIV positive,'' said Thio. ''Our results were surprising in that self-recovery is not so much a functionof speeding up the body's immune system to attack the hepatitis C virus as it is about taking the foot off the brakes so the body's killer immune cells can take off.''

Using a DNA analysis of the blood from more than 1,000 patients infected with hepatitis C, of whom 350 recovered on their own without therapy, the researchers were able to determine what genetic characteristics were more common in those who self-recovered than in those who did not. They found that the genes for a key protein, a receptor called KIR2DL3, in combination with genes for its key ligand, or attaching molecule called HLA, were more common in patients who self-recovered from hepatitis C. This combination was active only in those patients who were homozygous for this KIR2DL3-HLA, meaning two copies of the gene, one from each parent, were required for self-recovery to happen. Among those who received a presumed low viral dose, two copies of the KIR2DL3-HLA receptor-ligand combination were found in 20 percent who self-recovered from their infection, while it was present in just 10 percent who did not self-recover.

An important function of the KIR receptors is suppressing the action of the body's killer immune cells, serving as a chemical signal to not attack otherwise healthy cells. Conversely, when the KIR receptors are not suppressing the immune system, the killer immune cells can be activated and turned on to rid unwanted cells from the body, such as bacteria and viruses like hepatitis.

The researchers focused their efforts on the genes involved with killer immune cells because earlier studies in animals had shown that natural killer cells were more active in those who self-recovered from hepatitis C infection than in those who did not.

''It remains to be explained how these genes and viral dose at the time of infection interact in determining self-recovery from hepatitis C,'' added Thio. ''It can only be hypothesized at this point that high-dose infections possibly overwhelm the body's killer immune system, whereaslow-dose infections do not.''

''This study puts the spotlight on activating or not activating the inhibitory signals of the innate immune response,'' said a senior study author and infectious disease specialist David Thomas, M.D., professor of medicine at Hopkins. ''Whether it is possible to manipulate these very specific signals to promote recovery from hepatitis C remains to be seen. In the meantime, this finding is an important step forward in our understanding of hepatitis C recovery.''

Funding for this multinational study was provided by the National Institutes of Health, the Centers for Disease Control, Hope Charity and the Medical Research Council, National Health Service, United Kingdom.

Other investigators in this research, led by Mary Carrington at the National Cancer Institute, were Salim Khakoo, Collin Brooks and William Rosenberg, Southhampton University, U.K.; Maureen Martin, Xiaojian Gao, Jie Cheng, James Goedert, and Stephen O'Brien, also from the National Cancer Institute; David Vlahov, New York Academy of Medicine; Margaret Hilgartner, New York Presbyterian Hospital-Cornell Medical Center; Steven Cox and Ann-Margaret Little, The Royal Free Hospital, London, U.K.; Graeme Alexander, University of Cambridge, U.K.; Matthew Cramp, Derriford Hospital, Plymouth, U.K.; and Jacquie Astemborski, also from Hopkins.

Hepatitis C is the leading cause of liver disease in the United States and the most serious form of hepatic infection. It affects more than 4 million people in the United States, with an estimated 10,000 to 12,000 deaths each year. Hepatitis C is transmitted by contact with blood and other body fluids of an infected person, through sexual activities, injection drug use, sharing of personal care items or direct contact.

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Brain study points to 'sixth sense'

Following the Asian tsunami, scientists struggled to explain reports that primitive aboriginal tribesmen had somehow sensed the impending danger in time to join wild animals in a life-saving flight to higher ground. A new theory suggests that the anterior cingulate cortex, described by some scientists as part of the brain's "oops" center, may actually function as an early warning system -- one that works at a subconscious level to help us recognize and avoid high-risk situations.

While some scientists discount the existence of a sixth sense for danger, new research from Washington University in St. Louis has identified a brain region that clearly acts as an early warning system -- one that monitors environmental cues, weighs possible consequences and helps us adjust our behavior to avoid dangerous situations.

"Our brains are better at picking up subtle warning signs than we previously thought," said Joshua Brown, Ph.D., a research associate in psychology in Arts & Sciences and co-author of a study on these findings in the Feb. 18 issue of the journal Science.

The findings offer rigorous scientific evidence for a new way of conceptualizing the complex executive control processes taking place in and around the anterior cingulate cortex (ACC), a brain area located near the top of the frontal lobes and along the walls that divide the left and right hemispheres.

"In the past, we found activity in the ACC when people had to make a difficult decision among mutually exclusive options, or after they made a mistake," Brown said. "But now we find that this brain region can actually learn to recognize when you might make a mistake, even before a difficult decision has to be made. So the ACC appears to act as an early warning system -- it learns to warn us in advance when our behavior might lead to a negative outcome, so that we can be more careful and avoid making a mistake."

Implications for mental illness

The ACC has been the focus of intensive scientific research in recent years because it plays a critical role in the brain's processing of especially complex and challenging cognitive tasks. Abnormalities in the region are closely associated with a host of serious mental problems, including schizophrenia and obsessive-compulsive disorder.
Researchers provided study participants with a series of blue or white cues and asked them to push one button or another depending on the direction of arrows. Brain imaging suggested that an area of the brain had learned to recognize that blue cues indicated a greater potential for error, thus providing an early warning signal that negative consequences were likely to follow their behavior.

By providing a clearer picture of the cognitive mechanisms by which we self monitor and control our behavior, the study is an important step in efforts to develop more effective treatments for mental illness. It also provides a new way of understanding inappropriate behaviors that often accompany mental illnesses.

"Our results suggest how impairment of the ACC mechanisms in schizophrenia can lead to breakdowns in the early warning system, so that the brain fails to pre-empt or control inappropriate behavior," Brown said. "On the other hand, in individuals with obsessive-compulsive disorder, the ACC might warn of an impending problem even when no problem is imminent."

"Interestingly, we also found evidence that the same neurotransmitter involved in drug addiction and Parkinson's disease, namely dopamine, seems to play a key role in training the ACC to recognize when to send the early warning signal," he added.

Known to be an important component of the brain's executive control system, the ACC is believed to help mediate between cold, hard, fact-based reasoning and emotional responses, such as love, fear or anticipation.

"For a long time we've been interested in how the brain figures out how to integrate cognitive information about the world with our emotions, how we feel about something," Brown said. "For many reasons, people think the ACC might be the brain structure responsible for converging these different signals. It seems to be an area that's involved in deciding what information gets prioritized in the decision-making process. It seems able to link motivational and affect information - things like goodness or badness - and to use this information to bring about changes in cognition, to alter how we think about things."

New paradigm for brain's "oops" region

While there is growing consensus about the important role played by the cingulate in complex thoughts and feelings, there are competing theories regarding the cognitive mechanisms that underlie activity there.

Recent studies have documented spikes of activity in the ACC just as people realize that they've made a mistake of some kind, a sensation some describe as the "oops" moment (or, in more informal terms, as the "Oh S***" response). Theories based on these findings suggest that the primary role of the ACC is to help detect and subsequently correct mistakes or, alternatively, to detect the state of high-conflict that often accompanies mistakes"

Brown's study, co-authored with Todd Braver, Ph.D., associate professor of psychology in Arts & Sciences, offers compelling evidence that the ACC is better understood as a pre-emptive early warning system, one that is actively working to help us anticipate the potential for mistakes and thus avoid them altogether.

"We started with the premise that perhaps the cingulate was not responding to the detection of an error or state of conflict, but maybe instead what the cingulate is detecting is the likelihood of making an error," Brown said. "We wanted to see if the cingulate would become more active even in situations where no conflict is presented and no errors are made, but the potential for error is still higher than normal"

Methodology

To test their hypothesis, Brown and Braver developed an experiment requiring healthy young people to respond to a series of cues on a computer screen. Participants were presented with either a white or a blue dash, which soon changed into a small arrow pointing either right or left. They were instructed to quickly push one of two buttons depending on the arrow's direction. To simulate conflict, researchers occasionally slipped in a larger second arrow that required participants to change gears and push the opposite button.

"The idea is that at some point you have these competing tendencies - to push the right or left button -- and both are active in brain at same time, which creates conflict," explains Brown. "Some theories suggest that whenever you see these two arrows, then that drives this state of conflict and it's the state of conflict that is being detected by the cingulate."

By increasing the delay before presentation of the larger second arrow, researchers raised the odds that an individual would reach "the point of no return" and thus be unable to change gears in time to avoid pushing the wrong button. They then adjusted the delay time over many trials so that each participant eventually exhibited error rates of about 50 percent when provided with an initial blue priming dash, compared with error rates of only 4 percent when presented with a white priming dash.

Using functional magnetic resonance imaging (fMRI), researchers captured images of brain activity at 2.5-second intervals throughout the experiment.

"We didn't tell them that the white or blue cue offered any clue about their likelihood of making an error on any particular trial, but by the end of the session, some of them had begun to figure it out, at least on a subconscious level," Brown said.

Even among those who remained relatively unaware of the blue cue's significance, researchers found that simply showing the blue color was eventually enough to spark increased activity in the cingulate, and that this effect strengthened over time as the subject became more familiar with the task. Thus, brain imaging confirmed that the ACC had "learned" the significance of the blue cue, and had begun, at least subconsciously, to adjust behaviors accordingly, the study found.

"It appears that this area of the brain is somehow figuring out things without you necessarily having to be consciously aware of it," Brown said. "It makes sense that this mechanism exists because there are plenty of situations in our everyday lives that require the brain to monitor subtle changes in our environment and adjust our behavior, even in cases where we may not be necessarily aware of the conditions that prompted the adjustment. In some cases, the brain's ability to monitor subtle environmental changes and make adjustments may actually be even more robust if it takes place on a subconscious level."

Computer model of brain spurs new discoveries

In addition to its findings, the study is significant within scientific circles because of its use of sophisticated computer models to accurately predict the patterns of brain activation that would be sparked by the experiment, patterns only later confirmed by the imaging data from actual real-world trials.

"We started by building a detailed computer simulation of the ACC, and then we found that the computer predicted the existence of the early warning signal in ACC," Brown said. "This was an exciting result, but we still needed to test the prediction in humans to demonstrate that the model prediction was correct."

The researchers also tested their theory using another computer model that had been previously developed to support an existing theory of the ACC as a system focused on conflict resolution.

"By simulating both models we could then adjudicate between them and do so in a way where we forced each one to make predictions that we only tested after the fact," Brown said. "By integrating the theory, the computational simulation and then the fMRI testing, we are providing other scientists with some very rigorous evidence that our new theory is accurate."

During the last two decades, as computers have become much more powerful, computer modeling has become an increasingly powerful tool for understanding the brain, said Brown, noting that findings from this study offer a nice example of how computer models of the brain can lead to new discoveries.

"In fact, our computer model also makes some other exciting predictions about how the ACC works, but we haven't had an opportunity to test them yet," Brown said. "We've got our work cut out for us."

From Washington University in St. Louis

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Astonishing Scientific Achievements Of Ancient India!

Astonishing Scientific Achievements Of Ancient India!



Acharya Bharadwaj (800 BCE) was the pioneer of aviation technology and has written ‘Yantra Sarvasa’ which includes astonishing and outstanding discoveries. He at the time described three categories of flying machines that travel from one planet to another but also astonishingly from one universe to another. Space travel existed in the ancient Vedic times, something that science today has even barely broken the surface on.

Acharya Kapil (3000 BCE) was the father of cosmology. His research on primal matter and creation makes today's science look like an introductory course. The big bang theory? How about when he answers questions on the creation of the universe. Hindus were far ahead of their times. The proof exists in our sacred books.

Acharya Charak (600 BCE) was the father of Medicine. His renowned work ‘Charak Samhita’ which is considered the encyclopedia of Ayurveda today goes in depth about his principals, diagnoses and cures that still retain their potency and truth even after a couple of millennia. His research led to the facts of the Human anatomy, embryology, pharmacology, blood circulation and diseases like diabetes , tuberculosis, heart disease, etc. Charak Samhita describes medicinal qualities and functions of 100,000 herbal plants that today's science is still doing research on.

Acharya Kanad (600 BCE) was the founder of Atomic Theory. In his ‘Vaisheshik Darshan’ treatise he wrote "Every object of creation is made of atoms which in turn connect with each other to form molecules". This statement ushered in the Atomic Theory for the first time ever in the world, nearly 2500 years before John Dalton.

Rishi Nagarjuna (100 CE) The Master of Chemical Science. His vast research produced maiden discoveries and inventions in the faculties of Chemistry and Metallurgy. His textual masterprices like ‘Ras Ratnakar’, ‘Rashrudaya’ and ‘Rasendramangal’ are his contributions to Chemistry. Where medieval alchemists of England failed, Rishi Nagarjuna has discovered the alchemy of transmuting base metals into gold. His discoveries still impress and astonish scientists today.

Rishi Aryabhatt (476 CE) Master Astronomer and Mathematician. At the age of just 23 he wrote a text on astronomy and an unparalleled treatise on mathematics called ’Aryanbhatiyam’. He formulated the process of calculating the motion of planets and the time of eclipses. (100 years ago, the church had problems describing and accepting this as a scientific phenomenon). Aryabhatt was the first to claim that the earth was round, it rotates on its axis, orbits the sun and suspended in space – 1000 years ago before Copernicus published his heliocentric theory. Aryabhatt was the first to acknowledge the Pi to four decimal place (3.1416) and the sine table in trigonometry. Centuries later, in 825 CE, the Arab mathematician Ibna Musa credited the value of Pi to the Indians, "This value has been given by the Hindus". Above all Rishi Aryabhatt’s most spectacular contribution is the concept of zero without which modern computers technology would have been non-existent.

Rishi Varahamihir (499-587 CE) - Master Scientist, Astrologer and Astronomer. In his book ‘Panchsiddhant’, he notes that the moon and the planets are lustrous not because of their own light but due to sunlight. In the ‘Bruhad Samhita’ and ‘Bruhad Jatak’, he revealed his discoveries in the domains of geography, constellation science, botany and animal science.

Rishi Bhaskaracharya II (1114-1183) - Master of Algebra/Geometry/Astronomy. His works in Algebra, Arithmetic and Geometry catapulted him to fame and immortality. His renowned works are ‘Lilavani’ and ‘Bijaganita’ which are considered unparalleled. In his works ‘Surya Siddhant’, he makes a note on the force of gravity: "Objects fall on earth due to a force of attraction by the earth. Therefore the earth, the planets, constellations, moon and sun are held in orbit due to this attraction".

Bhaskaracharya was the first to discover gravity, 500 years before Isaac Newton.

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50 new animal species astonish conservationists

A bright-green tree frog with huge black eyes, jumping spiders and a striped gecko are among more than 50 new animal species scientists have discovered in a remote, mountainous region of Papua New Guinea.

The discoveries were announced yesterday by Washington DC-based Conservation International, which spent the past several months analyzing more than 600 species the group found during its expedition to the South Pacific island nation last summer.

Of the discoveries, 50 spider species, three frogs and a gecko appear to have never been described in scientific literature before.

The new frogs include a tiny brown animal with a sharp chirp, a bug-eyed bright-green tree frog and another frog with a loud ringing call. One of the jumping spiders is shiny and pale green, while another is furry and brown.

"If you're finding things that are that big and that spectacular that are new, that's really an indication that there's a lot out there that we don't know about," said expedition leader Steve Richards. "It never ceases to amaze me the spectacular things that are turning up from that island."

The findings are significant, particularly the discovery of the new frog species, said Craig Franklin, a zoology professor at The University of Queensland in Australia.

"They're often regarded as a great bioindicator of environmental health," said Franklin. "Often we see declines in frogs as a direct pointer to an affected environment."

Researchers from Conservation International explored the region with scientists from the University of British Columbia in Canada and Montclair State University in New Jersey, as well as local scientists from Papua New Guinea.

The area explored provides a critical source of clean drinking water to tens of thousands of people living in surrounding communities, and local clans rely on the region for hunting.

Montclair State University anthropologist William Thomas worked with the local Hewa clan to document the area's resources during the expedition as part of a project he started with scientist Bruce Beehler of Conservation International.

Conservation International plans to conduct three more expeditions to Papua New Guinea this year, in the hopes of turning up even more new animals.

"Most of us live in urban worlds where we think everything's totally well known," Beehler said.

"It's a little bit of a reminder, just a wake up call, that we really need to know our world better so we can manage it better."

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Geology of the Grand Canyon area

The geology of the Grand Canyon area exposes one of the most complete sequences of rock anywhere, representing a period of nearly 2 billion years of the Earth's history in that part of North America. The major sedimentary rock layers exposed in the Grand Canyon and in the Grand Canyon National Park area range in age from 200 million to nearly 2 billion years old. Most were deposited in warm, shallow seas and near ancient, long-gone sea shores. Both marine and terrestrial sediments are represented, including fossilized sand dunes from an extinct desert.
Uplift of the region started about 75 million years ago in the Laramide orogeny, a mountain-building event that is largely responsible for creating the Rocky Mountains to the east. Accelerated uplift started 17 million years ago when the Colorado Plateaus (on which the area is located) were being formed. In total these layers were uplifted an estimated 10,000 feet (3,000 m) which enabled the ancestral Colorado River to cut its channel into the four plateaus that constitute this area.
The canyon, created by the Colorado River is 277 miles (446 km), ranges in width from 4 to 18 miles (6.4 to 29 km) and attains a depth of more than a mile (1.6 km). Nearly two billion years of the Earth's 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.
Wetter climates brought upon by ice ages starting 2 million years ago greatly increased excavation of the Grand Canyon, which was nearly as deep as it is now by 1.2 million years ago. Also about 2 million years ago volcanic activity started to deposit ash and lava over the area. At least 13 large lava flows dammed the Colorado River, forming huge lakes that were up to 2,000 feet (610 m) deep and 100 miles (160 km) long. The nearly 40 identified rock layers and 14 major unconformities (gaps in the geologic record) of the Grand Canyon form one of the most studied sequences of rock in the world.

Deposition of sediments

Some important terms: A geologic formation is a rock unit that has one or more sediment beds, and a member is a minor unit in a formation. Groups are sets of formations that are related in significant ways, and a supergroup is a sequence of vertically related groups and lone formations. The various kinds of unconformities are gaps in the geologic record. Such gaps can be due to an absence of deposition or due to subsequent erosion removing the rock units.

Vishnu Group

The Vishnu Group had its beginnings about 2 billion years ago in Precambrian time when thousands of feet of ash, mud, sand, and silt were laid down in a shallow backarc basin similar to the modern Sea of Japan. During this time period the basin was between Laurentia (proto-North America/Europe) and an orogenic belt of mountains and volcanoes in an island arc not unlike today's Japan. From 1.84 to 1.65 billion years ago the Yavapai and Mojave provinces (island arcs) and then the Mazatzal province collided and accreted with the Wyoming craton of the proto-North American continent. This process of plate tectonics compressed and accreted marine sediments onto Laurentia. Essentially the island arcs slammed into the growing continent and the marine sediments in-between were squeezed together and uplifted out of the sea.
This is the metamorphic rock now exposed at the bottom of the canyon in the Inner Gorge. Geologists call this dark-colored, garnet-studded layer the Vishnu Schist. Combined with the other schists of this period, the Brahma and the Rama, this makes up the Vishnu Group (see 1a in figure 1). No identifiable fossils have been found in these strata, but lenses of marble now seen in these units were likely derived from colonies of primitive algae.[1]
The Vishnu Group was intruded by blobs of magma rising from a subduction zone offshore as recently as 1.66 billion years ago. These plutons slowly cooled to form the Zoroaster Granite (seen as light-colored bands in the darker Vishnu Schist; see 1b in Figure 1). Some of this rock eventually was metamorphosed into gneiss. The intrusion of the granite occurred in three phases: two during the initial Vishnu metamorphism period, and a third around 1.5 billion years ago. This third phase was accompanied by large-scale geologic faulting, particularly along north-south faults that caused some rifting, and a possible partial breakup of the continent..[2]
Studies of the sequence of rocks show that the Vishnu Group underwent at least two periods of orogeny (mountain-building). These orogenies created the 5-to-6-mile (8 to 10 km) high Mazatzal Mountains (Yavapai-Mazatzal orogeny).[3] This was a very high mountain range, possibly as high as or higher than the modern Himalaya. Then, for over 500 million years, erosion stripped much of the exposed sediments and the mountains away. This reduced this very high range to small hills a few tens to hundreds of feet (tens of meters) high, leaving a major angular unconformity. The once deeply buried mountain roots were all that remained of the Mazatzal Mountains as the sea reinvaded.
During the late Cretaceous or early Tertiary time the Farallon tectonic plate subducted under the west coast of the North American plate causing a compressional force across the region that resulted in an uplift and the formation of the Colorado Plateau.

Grand Canyon Supergroup

In late Precambrian time, extension from a large tectonic plate or smaller plates moving away from Laurentia thinned its continental crust, forming large rift basins (this rifting ultimately failed to split the continent). Eventually, a region of Laurentia from at least present-day Lake Superior to Glacier National Park in Montana to the Grand Canyon and the Uinta Mountains was invaded by a shallow seaway.[1] The resulting Grand Canyon Supergroup of sedimentary units is composed of nine varied formations that were laid down from 1250 million to 825 million years ago in this sea. The total thickness of the sediment and lava deposited was well over 2 miles (3 km). Rock outcroppings of the Grand Canyon Supergroup appear in parts of the Inner Gorge and in some of the deeper tributary canyons.
The oldest section of the supergroup is the Unkar Group (a group is a set of two or more formations that are related in notable ways). It was laid down in an offshore environment.
Bass Limestone (averages 1250 million years old) – Wave action eroded the land, creating a gravel that later lithified into a basal conglomerate. This formation is known as the Hotauta Member of the Bass Limestone. The Bass Limestone formation was deposited in a shallow sea near the coast as a mix of limestone, sandstone, and shale. It is 120 to 340 feet (37 to 100 m) thick and grayish in color. This is the oldest layer exposed in the Grand Canyon that contains fossils—stromatolites.
Hakatai Shale (averages 1200 million years old) – The Hakatai Shale is made of thin beds of non-marine-derived mudstones, sandstones, and shale. This formation indicates a short-lived regression (retreat) of the seashore in the area that left mud flats. Today it is very bright orange-red and gives the Red Canyon its name.
Shinumo Quartzite – This formation was a resistant marine sandstone that later formed islands in Cambrian time. Those islands withstood wave action long enough to become re-buried by other sediments in the Cambrian Period. It was later metamorphosed into quartzite.
Dox Sandstone (averages 1190 million years old) – A shallow formation made of ocean-derived sandstone with some interbedded shale beds and mudstone. Ripple marks and other features indicate it was close to the shore. Outcrops of this red to orange formation can be seen in the eastern parts of the canyon. Fossils of stromatolites and algae are found in this layer.
Cardenas Lava (1250 to 1100 million years old) – This is the youngest formation of the Unkar Group and is made of layers of dark brown basaltic rocks that flowed as lava up to 1,000 feet (300 m) thick.
The Nankoweap Formation averages 1050 million years old and is not part of a group. This rock unit is made of coarse-grained sandstone, and was deposited in a shallow sea on top of the eroded surface of the Cardenas Lava. The Nankoweap is only exposed in the eastern part of the canyon. A gap in the geologic record, an unconformity, follows the Nankoweap.
All formations in the Chuar Group (about 1000 to 825 million years old) were deposited in coastal and shallow sea environments.[4]
Galeros Formation – A mainly greenish formation composed of interbedded sandstone, limestone, and shale with some shale ranging in color from red to purple. Fossilized stromatolites are found in the Galeros.
Kwagunt Formation – The Kwagunt consists of black shale and red to purple mudstone with some limestone. Isolated pockets of reddish sandstone are also found around Carbon Butte. Stromatolites are found in this layer.
Sixtymile Formation – Sixtymile is made of tan-colored sandstone with some small sections of shale.
About 800 million years ago the supergroup was tilted 15° and block faulted in the Grand Canyon Orogeny.[5][6] Some of the block units moved down and others moved up while fault movement created north-south-trending fault-block mountain ranges. Some 100 million years of erosion took place that washed most of the Chuar Group away along with part of the Unkar Group (exposing the Shinumo Quartzite as previously explained). The mountain ranges were reduced to hills, and in some places, the whole 12,000 feet (3,700 m) of the supergroup were removed entirely, exposing the Vishnu Group below. This created what geologist John Wesley Powell called the Great Unconformity, itself one of the best examples of an exposed nonconformity (an unconformity with bedded rock units above igneous or metamorphic rocks) in the world. In all some 250 million years of the area's geologic history was lost in the Great Unconformity.[7] Good outcrops of the Grand Canyon Supergroup and the Great Unconformity can be seen in the upstream portion of the Inner Gorge.

Recent geology, human impact, and the future

The end of the Pleistocene ice ages and the start of the Holocene began to change the area's climate from a cool, wet pluvial one to dryer semi-arid conditions similar to that of today (although much of the rim then, as now, received enough precipitation to support large forests). With less water to cut, the erosive ability of the Colorado was greatly reduced (the rocks of the Inner Gorge are also relatively resistant to erosion). Mass wasting processes thus began to become relatively more important than they were before, creating steeper cliffs and further widening the Grand Canyon and its tributary canyon system.
In modern times, the building of the Glen Canyon Dam and other dams further upstream have regulated the flow of the Colorado River and have substantially reduced the amount of water and sediment it carries. This has diminished the river's ability to scour rocks, and the demand for water is so great that in most years the Colorado does not reach its delta in the Gulf of California.
The dam has also changed the character of the river water. Once both muddy and warm, with only bottom feeding fish, the river is now clear and cold and now supports planted trout. This in turn has changed the migration patterns of the bald eagle, which previously would transit the canyon to favorable fishing sites downstream, but now use the river as their seasonal feeding site.
About 45 earthquakes occurred in or near the Grand Canyon in the 1990s. Of these, five registered between 5.0 and 6.0 on the Richter Scale. Dozens of faults cross the canyon, with at least several active in the last 100 years.
The stream gradient of the Colorado River is still steep enough to suggest that the river could cut another 1200 to 2000 feet (400 to 600 m) assuming no additional uplift in the geologic future. This does not account for human impact, which would tend to slow the rate of erosion.

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