Contact Information:
Rob Enslin
rmenslin@syr.edu
315-443-3403
Syracuse University



Kredyty mieszkaniowe Kredyty mieszkaniowe

Sprawdź aktualny ranking najlepszych kredytów mieszkaniowych w Polsce - atrakcyjne kredytowanie nieruchomości.
PRESS-NEWS.org - Press Release Distribution
FREE PRESS RELEASES DISTRIBUTION
RSS - Press News Release
Add Press Release

Syracuse geologists shed light on formation of Alaska Range

Paul Fitzgerald says range's 'dramatic topography' is 25 million years in making


Syracuse geologists shed light on formation of Alaska Range
2014-11-19
(Press-News.org) Geologists in Syracuse University's College of Arts and Sciences have recently figured out what has caused the Alaska Range to form the way it has and why the range boasts such an enigmatic topographic signature. The narrow mountain range is home to some of the world's most dramatic topography, including 20,320-foot Mount McKinley, North America's highest mountain.

Professor Paul Fitzgerald and a team of students and fellow scientists have been studying the Alaska Range along the Denali fault. They think they know why the fault is located where it is and what accounts for the alternating asymmetrical, mountain-scale topography along the fault.

Their findings were the subject of a recent paper in the journal Tectonics (American Geophysical Union, 2014).

In 2002, the Denali fault, which cuts across south-central Alaska, was the site of a magnitude-7.9 earthquake and was felt as far away as Texas and Louisiana. It was the largest earthquake of its kind in more than 150 years.

"Following the earthquake, researchers flocked to the area to examine the effects," says Fitzgerald, who serves as professor of Earth Sciences and an associate dean for the College. "They were fascinated by how the frozen ground behaved; the many landslides [the earthquake] caused; how bridges responded; and how the Trans-Alaska oil pipeline survived, as it was engineered to do so."

Geologists were also surprised by how the earthquake began on a previously unknown thrust-fault; then propagated eastward, along the Denali fault, and finally jumped onto another fault, hundreds of kilometers away.

"From our perspective, the earthquake has motivated analyses of why the highest mountains in the central Alaska Range occur south of the Denali fault and the highest mountains in the eastern Alaska Range occur north of the fault--something that has puzzled us for years," Fitzgerald adds. "It's been an enigma staring us in the face."

He attributes the Alaska Range's alternating topographic signatures to a myriad of factors: contrasting lithospheric strength between large terranes (i.e., distinctly different rock units); the location of the curved Denali fault; the transfer of strain inland from southern Alaska's active plate margin; and the shape of the controlling former continental margin against weaker suture-zone rocks.

It's no secret that Alaska is one of the most geologically active areas on the planet. For instance, scientists know that the North American Plate is currently overriding the Pacific Plate at the latter's southern coast, while the Yakutat microplate is colliding with North America.

As a result of plate tectonics, Alaska is an amalgamation of terranes that have collided with the North American craton and have accreted to become part of North America.

Cratons are pieces of continents that have been largely stable for hundreds of millions of years.

Terranes often originate as volcanic islands (like those of Hawaii) and, after colliding with one another or a continent, are separated by large discrete faults. When terranes collide and accrete, they form a suture, also known as a collision zone, which is made up of weak, crushed rock. During deformation, suture-zone rocks usually deform first, especially if they are adjacent to a strong rock body.

"Technically, the Denali fault is what we'd call an 'intercontinental right-lateral strike-slip fault system,'" says Fitzgerald, adding that a strike-slip fault occurs when rocks move horizontally past one another, usually on a vertical fault. "This motion includes a component of slip along the fault and a component of normal motion against the fault that creates mountains. Hence, the shape of the fault determines which of the two components is predominant and where mountains form."

In Alaska, the shape of the accreted terranes generally controls the location of the Denali fault and the mountains that form along it, especially at the bends in the trace of the fault.

Fitzgerald: "Mount McKinley and the central Alaska Range lie within the concave curve of the Denali fault. There, higher topography and greater exhumation [uplift of rock] occur south of the Denali fault, exactly where you'd expect a mountain range to form, given the regional tectonics. In the eastern Alaska Range, higher topography and greater exhumation are found north of the fault, on its convex side--not an expected pattern at all and very puzzling."

Using mapped surface geology, geophysical data, and thermochronology (i.e., time-temperature history of the rocks), Fitzgerald and colleagues have determined that much of Alaska's uplift and deformation began some 25 million years ago, when the Yakutat microplate first started colliding with North America. The bold, glacier-clad peaks comprising the Alaska Range actually derive from within the aforementioned "weak suture-zone rocks" between the terranes.

While mountains are high and give the impression of strength, they are built largely from previously fractured rock units. Rock movement along the Denali fault drives the uplift of the mountains, which form at bends in the fault, where previously fractured suture-zone rocks are pinned against the stronger former North American continental margin.

"The patterns of deformation help us understand regional tectonics and the formation of the Alaska Range, which is fascinating to geologists and non-geologists alike," says Fitzgerald. "Being able to determine patterns or how to reveal them, while others see chaos, is often the key to finding the answer to complex problems. ... To us scientists, the real significance of this work is that it helps us understand the evolution of our planet, how faults and mountain belts form, and why earthquakes happen. It also provides a number of hypotheses about Alaskan tectonics and rock deformation that we can test, using the Alaska Range as our laboratory."

INFORMATION:

In addition to Fitzgerald, the paper was co-authored by Sarah Roeske, a research scientist at the University of California, Davis; Jeff Benowitz, a research scientist at the Geophysical Institute at the University of Alaska Fairbanks; Steven Riccio and Stephanie Perry, graduate students in Earth Sciences at Syracuse; and Phillip Armstrong, professor and chair of geological sciences at California State University, Fullerton.

Housed in Syracuse's College of Arts and Sciences, the Department of Earth Sciences offers graduate and undergraduate degree opportunities in crustal evolution and tectonics, environmental sciences and climate change, hydrogeology, sedimentology and paleolimnology, geochemistry, and paleobiology.


[Attachments] See images for this press release:
Syracuse geologists shed light on formation of Alaska Range Syracuse geologists shed light on formation of Alaska Range 2

ELSE PRESS RELEASES FROM THIS DATE:

Power behind 'master' gene for cancer discovered

Power behind master gene for cancer discovered
2014-11-19
It's hard to believe, but there are similarities between bean sprouts and human cancer. In bean sprouts, a collection of amino acids known as a protein complex allows them to grow longer in the darkness than in the light. In humans, a similar protein complex called CSN and its subunit CSN6 is now believed to be a cancer-causing gene that impacts activity of another gene (Myc) tied to tumor growth. Somehow the same mechanisms that result in bigger bean sprouts, also cause cancer metastasis and tumor development. A study at The University of Texas MD Anderson Cancer ...

Camera trap images help wildlife managers ID problem tigers in India

Camera trap images help wildlife managers ID problem tigers in India
2014-11-19
Human-wildlife conflict resolution near protected areas critical for tiger survival Stripe-matching software and individual histories inform decisions on handling conflict-prone big cats NEW YORK (November 18, 2014)--Researchers with the Wildlife Conservation Society and other partners in India are using high-tech solutions to zero in on individual tigers in conflict and relocate them out of harm's way for the benefit of both tigers and people. In recent tiger-conflict cases involving both a human fatality and the predation of livestock, both occurring near two of ...

Living kidney donors more likely to be diagnosed with high BP or preeclampsia once pregnant

2014-11-19
Nearly 30,000 people become living kidney donors worldwide each year, and many are young women. Researchers at the Institute for Clinical Evaluative Sciences (ICES), Lawson Health Research Institute and Western University set out to determine if being a living donor has any effect on future pregnancies. The study, published in the New England Journal of Medicine, found living kidney donors were more likely to be diagnosed with gestational hypertension (high blood pressure) or preeclampsia than non-donors. Preeclampsia is a pregnancy complication characterized by high ...

South Asian boys are more likely to be overweight compared to peers, new study finds

2014-11-19
South Asian boys are three times as likely to be overweight compared to their peers, according to a new Women's College Hospital study. The report, which was recently published in the Journal of Racial and Ethnic Health Disparities, was one of the first to look at ethnic group differences in overweight children living in Canada. "Our findings are alarming. From a young age, South Asian boys appear to be on a path towards developing serious health conditions," said Ananya Banerjee, PhD, lead researcher of the study. Previous work has established that, in Canada, type ...

2008 Lacey Act Amendment successful in reducing US imports of illegally logged wood

2014-11-19
Recently published research by U.S. Forest Service economist Jeff Prestemon supports the contention that the 2008 Lacey Act Amendment reduced the supply of illegally harvested wood from South America and Asia available for export to the United States. Using monthly import data from 1989 to 2013, Prestemon, Project Leader of the Forest Service Southern Research Station Forest Economics and Policy unit, applied alternative statistical approaches to evaluate the effects of the 2008 amendment. The Journal of Forest Policy and Economics recently published the results online. ...

Common blood pressure medication does not increase risk of breast cancer, new study finds

2014-11-19
CHICAGO - Women who take a common type of medication to control their blood pressure are not at increased risk of developing breast cancer due to the drug, according to new study by researchers at the Intermountain Medical Center Heart Institute in Murray, Utah. Researchers analyzed the records of more than 3,700 women who had no history of breast cancer, and who had long-term use of calcium channel blocker medications to control their blood pressure. Researchers found only a minimal increase in risk in one study and a 50 percent reduced risk in a second, leading them ...

'Cloaking' device uses ordinary lenses to hide objects across continuous range of angles

Cloaking device uses ordinary lenses to hide objects across continuous range of angles
2014-11-19
Inspired perhaps by Harry Potter's invisibility cloak, scientists have recently developed several ways--some simple and some involving new technologies--to hide objects from view. The latest effort, developed at the University of Rochester, not only overcomes some of the limitations of previous devices, but it uses inexpensive, readily available materials in a novel configuration. "There've been many high tech approaches to cloaking and the basic idea behind these is to take light and have it pass around something as if it isn't there, often using high-tech or exotic ...

It pays to have an eye for emotions

It pays to have an eye for emotions
2014-11-19
Attending to and caring about the emotions of employees and colleagues - that's for wimps, not for tough businesspeople and efficient performers, right? Wrong! An extensive international study has now shown: The "ability to recognize emotions" affects income. The corresponding author of the study is Professor Dr. Gerhard Blickle of the Department of Psychology at the University of Bonn. The results are published in the Journal of Organizational Behavior. "Although managing employees and dealing with people often involves reading their emotions and determining their moods, ...

Prehistoric landslide discovery rivals largest known on surface of Earth

Prehistoric landslide discovery rivals largest known on surface of Earth
2014-11-19
A catastrophic landslide, one of the largest known on the surface of the Earth, took place within minutes in southwestern Utah more than 21 million years ago, reports a Kent State University geologist in a paper being to be published in the November issue of the journal Geology. The Markagunt gravity slide, the size of three Ohio counties, is one of the two largest known continental landslides (larger slides exist on the ocean floors). David Hacker, Ph.D., associate professor of geology at the Trumbull campus, and two colleagues discovered and mapped the scope of the ...

Bacterial infections suppress protective immune response in neurodermatitis

2014-11-19
This news release is available in German. Because the skin and its function as a barrier are severely compromised in neurodermatitis patients, a large number of bacterial species are able to multiply - including the bacterium Staphylococcus aureus. Many patients have nearly 200-times as many S. aureus bacteria living on their skin as healthy individuals, resulting in frequent infections. Prof. Tilo Biedermann and his team at the Allergology and Dermatology Clinic of Klinikum rechts der Isar and the University of Tübingen have now shown in an animal model how these ...

LAST 30 PRESS RELEASES:

How your brain decides blame and punishment -- and how it can be changed

Uniquely human brain region enables punishment decisions

Pinpointing punishment

Chapman University publishes research on attractiveness and mating

E-cigarettes: Special issue from Nicotine & Tobacco Research

Placental problems in early pregnancy associated with 5-fold increased risk of OB & fetal disorders

UT study: Invasive brood parasites a threat to native bird species

Criminals acquire guns through social connections

Restoring ocean health

Report: Cancer remains leading cause of death in US Hispanics

Twin study suggests genetic factors contribute to insomnia in adults

To be fragrant or not: Why do some male hairstreak butterflies lack scent organs?

International team discovers natural defense against HIV

Bolivian biodiversity observatory takes its first steps

Choice of college major influences lifetime earnings more than simply getting a degree

Dominant strain of drug-resistant MRSA decreases in hospitals, but persists in community

Synthetic biology needs robust safety mechanisms before real world application

US defense agencies increase investment in federal synthetic biology research

Robots help to map England's only deep-water Marine Conservation Zone

Mayo researchers identify protein -- may predict who will respond to PD-1 immunotherapy for melanoma

How much water do US fracking operations really use?

New approach to mammograms could improve reliability

The influence of citizen science grows despite some resistance

Unlocking secrets of how fossils form

What happens on the molecular level when smog gets into the lungs?

Using ultrasound to clean medical instruments

Platinum and iron oxide working together get the job done

Tiny silica particles could be used to repair damaged teeth, research shows

A quantum lab for everyone

No way? Charity's logo may influence perception of food in package

[Press-News.org] Syracuse geologists shed light on formation of Alaska Range
Paul Fitzgerald says range's 'dramatic topography' is 25 million years in making
Press-News.org is a service of DragonFly Company. All Rights Reserved.
Issuers of news releases are solely responsible for the accuracy of their content.