PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

A billion-year-old piece of North America traced back to Antarctica

A billion-year-old piece of North America traced back to Antarctica
2011-08-09
(Press-News.org) Boulder, CO, USA - An international team of researchers has found the strongest evidence yet that parts of North America and Antarctica were connected 1.1 billion years ago, long before the supercontinent Pangaea formed.

"I can go to the Franklin Mountains in West Texas and stand next to what was once part of Coats Land in Antarctica," said Staci Loewy, a geochemist at California State University, Bakersfield, who led the study. "That's so amazing."

Loewy and her colleagues discovered that rocks collected from both locations have the exact same composition of lead isotopes. Earlier analyses showed the rocks to be the exact same age and have the same chemical and geologic properties. The work, published online 5 August (ahead of print) in the September issue of the journal Geology, strengthens support for the so-called SWEAT hypothesis, which posits that ancestral North America and East Antarctica were joined in an earlier supercontinent called Rodinia.

The approximately 1.1 billion year old North American Mid-continent Rift System extends across the continent from the Great Lakes to Texas. Volcanic rocks associated with the rift, which appears to represent an aborted tectonic attempt to split the ancestral North American continent of Laurentia, are well exposed in the Keweenaw Peninsula of the Upper Peninsula of Michigan from which they take their name, the Keweenawan large igneous province. The rift extends in the subsurface beneath Minnesota, Iowa, Nebraska, Kansas and Oklahoma to the Franklin Mountains near El Paso, Texas where related rocks are exposed. In this latest report, Loewy, Ian Dalziel, research professor at The University of Texas at Austin, Richard Hanson of Texas Christian University and colleagues from several overseas institutions, find that rocks barely peeking through the ice in Coats Land, a remote part of the Antarctic continent south of the Atlantic Ocean basin, reflect a former continuation of the North American rift system. Loewy began her collaboration with Dalziel several years ago as a graduate student at the University of Texas at Austin.

Loewy et al. use new lead (Pb) isotopic data from the 1.1-billion-year-old rocks from Coats Land, to constrain the positions of Laurentia (ancestral North America) and Kalahari (ancestral southern Africa) in the 1-billion-year-old supercontinent, Rodinia. The Coats Land rocks are identical in age to both the Keweenawan large igneous province of the North American mid-continent rift and the contemporaneous Umkondo large igneous province of southern Africa. Comparison of the isotopic compositions, however, unequivocally links the Coats Land rocks with the Keweenawan province. Together with paleomagnetic data this suggests that the Coats Land block was a piece of Laurentia near west Texas 1.1 billion years ago. Furthermore, the Coats Land block collided with the Kalahari Precambrian craton of Africa during a 1-billion-year-old collision. Based on this reconstruction, Laurentia collided with Kalahari along Antarctica's Maud mountain belt, which would represent a continuation of the 1-billion-year-old Grenville mountain belt of eastern and southern North America.

Thus the tiny Coats Land block of Antarctica is a 'tectonic tracer' providing critical clues to the geographic relationships between three of the major continents of the planet in the time interval 1.1 – 1.0 billion years ago, just prior to the opening of the Pacific Ocean basin, the hypothesized 'Snowball Earth' glaciations, and the rise of multi-cellular life.



INFORMATION:

Coats Land crustal block, East Antarctica: A tectonic tracer for Laurentia?
Staci L. Loewy, Department of Geology, California State University, Bakersfield, Bakersfield, California 93311, USA, and co-authors (see *below).
E-mail: sloewy@csub.edu.

Abstract is available at http://geology.gsapubs.org/content/early/2011/08/05/G32029.1.abstract.

Additional contact: co-author Ian W. D. Dalziel, Institute for Geophysics, Jackson School of Geosciences, The University of Texas at Austin. E-mail: ian@ig.utexas.edu.

Representatives of the media may obtain complimentary copies of Geology articles by contacting Christa Stratton at the address above. Please discuss articles of interest with the authors before publishing stories on their work, and please make reference to Geology in articles published.

Non-media requests for articles may be directed to GSA Sales and Service, gsaservice@geosociety.org.

*S.L. Loewy1, I.W.D. Dalziel2, S. Pisarevsky3,7, J.N. Connelly4, J. Tait3, R.E. Hanson5, D. Bullen6

1 Department of Geology, California State University, Bakersfield, Bakersfield, CA 93311
2 Institute for Geophysics, The University of Texas at Austin, Austin, Texas 78758-4445
3 School of GeoScience, University of Edinburgh, King's Buildings, Edinburgh, EH9 3JW, UK
4 Centre for Star and Planet Formation, Copenhagen University, Copenhagen 1350, Denmark.
5 School of Geology, Energy and the Environment, Texas Christian University, Fort Worth, TX 76129
6 School of Earth and Environmental Sciences, University of Portsmouth, Portsmouth PO1 3QL, UK
7 School of Earth and Environment, University of Western Australia, Crawley, WA 6009, Australia

www.geosociety.org

Photo courtesy of Ian Dalziel: Coats Land with its only rock outcrops, Littlewood (L) and Bertrab (B) nunataks.

[Attachments] See images for this press release:
A billion-year-old piece of North America traced back to Antarctica

ELSE PRESS RELEASES FROM THIS DATE:

Distance caregivers for advanced cancer patients have special needs, CWRU study finds

2011-08-09
By 2012, an estimated 14 million people will serve as distance caregivers to family members who live across the state, across the region, even across the country. "No longer are families living just around the corner from each other," says Polly Mazanec, an assistant professor at the Frances Payne Bolton School of Nursing and an advance practice oncology nurse at University Hospitals Case Medical Center's Seidman Cancer Center. The distance presents a challenge as family members work to gain information about their loved ones and participate in their cancer care. But ...

Social class as culture

2011-08-09
Social class is more than just how much money you have. It's also the clothes you wear, the music you like, the school you go to—and has a strong influence on how you interact with others, according to the authors of a new article in Current Directions in Psychological Science, a journal of the Association for Psychological Science. People from lower classes have fundamentally different ways of thinking about the world than people in upper classes—a fact that should figure into debates on public policy, according to the authors. "Americans, although this is shifting a ...

Study: Graphic warning labels reduce demand for cigarettes

2011-08-09
Will graphic cigarette package warning labels significantly reduce demand? A new study suggests it will. Current US policy requires that tobacco companies cover 50 percent of one side of a cigarette pack with a text warning. But the FDA recently unveiled nine new cigarette warning labels, which include graphic images of lung and mouth cancer, to be unveiled in September 2012. A sample of 404 adult smokers from four states participated in an experimental auction on cigarette packs with four different kinds of warning labels. All packs carried the same message: smoking ...

SHSU studies GPS monitoring of Arizona sex offenders

2011-08-09
The use of GPS technology to monitor sex offenders should be viewed as a tool rather than a control mechanism, a team of researchers at Sam Houston State University found in a recent study. In "Examining GPS Monitoring Alerts Triggered by Sex Offenders: The Divergence of Legislative Goals and Practical Applications in Community Corrections," Dr. Gaylene Armstrong and Beth Freeman examined the affects of a state law in Arizona that required the lifelong GPS monitoring of adult sex offenders convicted of dangerous crimes against children and placed on community supervision. ...

Tactile technology guaranteed to send shivers down your spine

2011-08-09
PITTSBURGH—A new tactile technology developed at Disney Research, Pittsburgh (DRP), called Surround Haptics, makes it possible for video game players and film viewers to feel a wide variety of sensations, from the smoothness of a finger being drawn against skin to the jolt of a collision. The technology is based on rigorous psychophysical experiments and new models of tactile perception. Disney will demonstrate Surround Haptics Aug. 7-11 at the Emerging Technology Exhibition at SIGGRAPH 2011, the International Conference on Computer Graphics and Interactive Techniques ...

Urgent assessment in emergency departments can reduce surgical decision time and overcrowding

2011-08-09
CHICAGO (August 8, 2011) – The use of Acute Care Emergency Surgical Service (ACCESS) in emergency departments (EDs) can lead to significant reductions in key patient measures, such as length of stay, surgical decision-making time and "time-to-stretcher" (one measure of overall ED overcrowding), according to a study published in the August issue of the Journal of the American College of Surgeons. Emergency departments are a crucial point of access to the health care system for patients with a broad spectrum of injuries and illnesses, and overcrowding has been identified ...

Number of laparoscopic bariatric procedures continued to rise between 2003-2008

2011-08-09
CHICAGO (August 8, 2011) – According to a study published in the August issue of the Journal of the American College of Surgeons, there was an increase in the number of laparoscopic bariatric procedures, an increase in the number of bariatric surgeons and a decrease of inhospital mortality rates between 2003 and 2008. During the past decade, the field of bariatric surgery has changed dramatically and the authors concluded that these trends are due, in part, to an increase in the use of laparoscopic techniques and a greater acceptance of bariatric surgery by patients. "We've ...

You can count on this: Math ability is inborn

You can count on this: Math ability is inborn
2011-08-09
We accept that some people are born with a talent for music or art or athletics. But what about mathematics? Do some of us just arrive in the world with better math skills than others? It seems we do, at least according to the results of a study by a team of Johns Hopkins University psychologists. Led by Melissa Libertus, a post-doctoral fellow in the Department of Psychological and Brain Sciences at the Krieger School of Arts and Sciences, the study -- published online in a recent issue of Developmental Science -- indicates that math ability in preschool children is ...

Like superman's X-Ray vision, new microscope reveals nanoscale details

2011-08-09
Physicists at UC San Diego have developed a new kind of X-ray microscope that can penetrate deep within materials like Superman's fabled X-ray vision and see minute details at the scale of a single nanometer, or one billionth of a meter. But that's not all. What's unusual about this new, nanoscale, X-ray microscope is that the images are not produced by a lens, but by means of a powerful computer program. The scientists report in a paper published in this week's early online edition of the Proceedings of the National Academy of Sciences that this computer program, or ...

USC scientist develops virus that targets HIV

2011-08-09
In what represents an important step toward curing HIV, a USC scientist has created a virus that hunts down HIV-infected cells. Dr. Pin Wang's lentiviral vector latches onto HIV-infected cells, flagging them with what is called "suicide gene therapy" — allowing drugs to later target and destroy them. "If you deplete all of the HIV-infected cells, you can at least partially solve the problem," said Wang, chemical engineering professor with the USC Viterbi School of Engineering. The process is analogous to the military practice of "buddy lasing" — that is, having a ...

LAST 30 PRESS RELEASES:

Combining non-invasive brain stimulation and robotic rehabilitation improves motor recovery in mouse stroke model

Chickening out – why some birds fear novelty

Gene Brown, MD, RPh, announced as President of the American Academy of Otolaryngology-Head and Neck Surgery and its Foundation

Study links wind-blown dust from receding Salton Sea to reduced lung function in area children

Multidisciplinary study finds estrogen could aid in therapies for progressive multiple sclerosis

Final day of scientific sessions reveals critical insights for clinical practice at AAO-HNSF Annual Meeting and OTO EXPO

Social adversity and triple-negative breast cancer incidence among black women

Rapid vs standard induction to injectable extended-release buprenorphine

Galvanizing blood vessel cells to expand for organ transplantation

Common hospice medications linked to higher risk of death in people with dementia

SNU researchers develop innovative heating and cooling technology using ‘a single material’ to stay cool in summer and warm in winter without electricity

SNU researchers outline a roadmap for next-generation 2D semiconductor 'gate stack' technology

The fundamental traditional Chinese medicine constitution theory serves as a crucial basis for the development and application of food and medicine homology products

Outfoxed: New research reveals Australia’s rapid red fox invasion

SwRI’s Dr. Chris Thomas named AIAA Associate Fellow

National Collegiate Athletic Association (NCAA) funding for research on academic advising experiences of Division I Black/African American student-athletes at minority serving institutions

Johri developing artificial intelligence literacy among undergraduate engineering and technology students

Boston Children’s receives a $35 million donation to accelerate development of therapeutic options for children with brain disorders through the Rosamund Stone Zander and Hansjoerg Wyss Translational

Quantum crystals offer a blueprint for the future of computing and chemistry

Looking beyond speech recognition to evaluate cochlear implants

Tracking infectious disease spread via commuting pattern data

Underweight children cost the NHS as much per child as children with obesity, Oxford study finds.

Wetland plant-fungus combo cleans up ‘forever chemicals’ in a pilot study

Traditional Chinese medicine combined with peginterferon α-2b in chronic hepatitis B

APS and SPR honor Dr. Wendy K. Chung with the 2026 Mary Ellen Avery Neonatal Research Award

The Gabriella Miller Kids First Data Resource Center (Kids First DRC) has launched the Variant Workbench

Yeast survives Martian conditions

Calcium could be key to solving stability issues in sodium-ion batteries

Can smoother surfaces prevent hydrogen embrittlement?

Heart rate changes predict depression treatment success with magnetic brain stimulation

[Press-News.org] A billion-year-old piece of North America traced back to Antarctica