Friday, April 30, 2010

[Geology2] Dinosaur ecosystem the size of a continent

Retracing the tracks of dinosaurs reveals ecosystem the size of a
continent PhysOrg.com [USA], April 20, 2010

Researchers at McGill University are unlocking the mysteries of the
little-known habits of dinosaurs in discovering that the entire western
interior of North America was likely once populated by a single
community of dinosaurs. According to a statistical analysis of the
fossil record, dinosaurs were adept at coping with all sorts of
environments, and not as restricted in their geographic ranges as
previously thought. The discovery was made by McGill Professor Hans
Larsson and Matthew Vavrek, a PhD student at the University. Using data
from the Paleobiology Database, they found that the difference in
species between regions over North America was relatively low - low
enough to consider it a single homogeneous fauna. The finding is
significant as it confirms that dinosaur ecosystems may have been as
large as continents. The paper is to be published in the April 19 issue
of the journal Proceedings of the National Academy of Sciences.

http://www.physorg.com/news190971060.html

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[Volcano_Vista_HS] Coat Check at Prom



A Night in Venice -2010 Prom

The Parent Advisory will be  having a Coat ( Purse, Phone, Camera) Check at The Prom

The Cost is $1.oo

There are check out and in privledges for any stuff.

The parents will keep the students stuff safe.



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[Geology2] The Saltiest Body of Water on Earth



The Saltiest Body of Water on Earth


Don Juan Pond, Antarctica could serve as a model for liquid water on other planets.


Republished from an April, 2010 press release by The University of Georgia.

Don Juan Pond in a glacial valley
Don Juan Pond in Antarctica, a roughly 1,000- by 400-meter basin, is by far the saltiest body of water on Earth. The specks of red in this image are researchers who are dwarfed by the steep, rocky cliffs around them. UGA image. Enlarge image. Super Enlarge.

A Pond in Antarctica that Never Freezes!

In so many ways, Don Juan Pond in the Dry Valleys of Antarctica is one of the most unearthly places on the planet. An ankle-deep mirror between mountain peaks and rubbled moraine, the pond is an astonishing 18 times saltier than the Earth's oceans and virtually never freezes, even in temperatures of more than 40 degrees below zero Fahrenheit.

A Model for Brine Pools on Other Planets?

Now, a research team led by biogeochemists from the University of Georgia has discovered at the site a previously unreported chemical mechanism for the production of nitrous oxide, an important greenhouse gas. Possibly even more important, the discovery could help space scientists understand the meaning of similar brine pools in a place whose ecosystem most closely resembles that of Don Juan Pond: Mars.

The research, published April 25, 2010 in the journal Nature Geoscience, adds an intriguing new variable to growing evidence that there has been—and may still be—liquid water on Mars, a usual prerequisite for the formation of life. In fact, the new findings could help space scientists develop sensors for detecting such brines on Mars—thus narrowing the search for places where life may exist.

Assessing Microbial Activity in Extreme Environments

"The pond's soils and brines and the surrounding rock types are similar to those found on Mars," said Samantha Joye, a faculty member in the department of marine sciences in the Franklin College of Arts and Sciences and lead author on the paper. "So it provides an ideal location to assess microbial activity in extreme environments. While we did not detect any 'bio-gases' such as hydrogen sulfide and methane, we did, surprisingly, measure high concentrations of nitrous oxide, which is normally an indicator of microbial activity. We needed to find out whether a non-organic process could account for this nitrous oxide production."

The Author Team and Support

Other authors on the paper include Vladimir Samarkin, a research scientist, and Marshall Bowles, a graduate student, also of the department of marine sciences at UGA; Michael Madigan of Southern Illinois University; Karen Casciotti of the Woods Hole Oceanographic Institution; John Priscu of Montana State University; and Christopher McKay of the Ames Research Center of NASA.

The research was supported by grants from the National Science Foundation's Antarctic Organisms and Ecosystems Program and the McMurdo Microbial Observatory Program.

Scientists have been fascinated with Don Juan Pond since its discovery in 1961. (While the site is lovely, there's nothing romantic about the name, which comes from the helicopter pilots who first found it, Don Roe and John Hickey.) From the time of its discovery, researchers realized they had found a place like nowhere else on Earth.

sterile suits and masks
Researchers wore sterile suits and masks and used sterile instruments for sampling to avoid possible contamination of Don Juan Pond in Antarctica. They also collected the minimal amount of material necessary to achieve their research goals. UGA image.


measuring nitrous oxide
UGA research scientist Vladimir Samarkin and his colleagues measured the production of nitrous oxide, an important greenhouse gas, at Don Juan Pond in Antarctica and discovered at the site a previously unreported chemical mechanism for the production of this important greenhouse gas. The discovery could help space scientists understand the meaning of similar brine pools on Mars. UGA image.

The Saltiest Body of Water on Earth

The pond, which is a roughly 1,000- by 400-meter basin, is the saltiest body of water on Earth by far, some eight times saltier than the Dead Sea. While researchers more than 30 years ago reported finding abundant and varied microflora of fungi, bacteria, blue-green algae and yeasts, since then and during the Joye team's work, such life has been non-existent. Since the depth level and area covered by the pond (which is fed by hypersaline groundwater) have demonstrably varied over the years, this wasn't unexpected. What did surprise the team was that even with no life-forms present, they were able to measure nitrous oxide, perhaps best known to most people as the "laughing gas" used in dental procedures. (The amounts measured in the air were beneath a level that could make a person light-headed or giddy, as "laughing gas" can.)

Products of the Extreme Brine Environment

"What we found was a suite of brine-rock reactions that generates a variety of products, including nitrous oxide and hydrogen," said Joye. "In addition to Don Juan Pond, this novel mechanism may occur in other environments on Earth as well and could serve as both an important component of the Martian nitrogen cycle and a source of fuel [hydrogen] to support microbial chemosynthesis."

Even more interesting, perhaps, is that the results suggest that an additional mechanism — the reaction of brine-derived nitrates with basaltic rock — could be a "previously unrecognized means for mobilizing nitrate from the surface soils . . . and returning it to the Martian atmosphere as nitrous oxide," Joye said.

Liquid Water on Mars?

The discovery of water has been the holy grail of numerous Mars missions over the years, and in 2009 the Mars Phoenix mission's cameras photographed on the legs of the lander what appeared to be liquid water. If ultimately confirmed — and growing evidence appears to be solidifying in favor of such an analysis — it would be the first time liquid water was detected and photographed outside the Earth.

Working in such a beautiful but unearthly area presents stern challenges to researchers, Joye said.

"It's a 40-minute helicopter ride over the McMurdo Sound just to get there," she said. "Once in the Wright Valley, we enter a tight enclosure with steep, rocky cliffs on both sides, and between them is Don Juan Pond. I believe it must be one of the most beautiful places in Antarctica."

Samarkin agreed.

"It has the kind of beauty that rock parks in Japan have," he said, "except this is made by nature."

Protecting the Unique Environment

Beauty aside, though, the team had to dress in sterile suits and masks and use sterile instruments for sampling to avoid possible contamination. They also collected the minimal amount of material necessary to achieve their research goals.

The discovery of the new mechanism opens numerous questions that must be studied, including the possibility that the process is taking place in other extreme Antarctic habitats or that it might contribute to nitrous oxide in temperate soils—a possible new clue to understanding greenhouse gases involved in global warming.

The most crucial result, however, may be in understanding how similar brine pools on Mars might work and whether they could support life.


Source
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[Geology2] 150 Geological Facts about California



Click on the link below to download a .pdf:

150 Geologic Facts about California
April 29, 2010 | California Geological Survey

To celebrate their 150th anniversary, the California Geological Survey has prepared a list of "150 Geologic Facts about California". There are lots of interesting facts here. If you read them you will learn quite a few interesting things about the geology of the state.





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[Geology2] Beautiful wallpaper



Click here to see and download--it's awesome





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[Geology2] Is Arkansas at risk for an earthquake?




Is Arkansas at risk for an earthquake?

Reported by: Justin Earley
Email: jearley@fox16.com
Last Update: 8:51 am

We see the images jumping out of our TVs, the catastrophic damage from massive earthquakes. In Haiti, Chile, and Mexico, the quakes claimed lives and leveled buildings.

But what about the storied New Madrid Fault the runs through northeast Arkansas? It actually re-routed the Mississippi River in the early 1800s. But do these recent events point to a major quake here?

With the New Madrid seismic zone extending all the way from Cairo, Illinois to Marked Tree in northeast Arkansas, could we expect a major earthquake here and what would it do? To find those answers you need to go back in time.

From 1811 to 1812, the New Madrid Fault line gave us three of the most powerful earthquakes in U.S. History. It reached a magnitude of 8.0 on the richter scale and rang church bells all the way to Boston. In New Madrid, Missouri, cracks opened up in the ground. The earth's surface visibly rolled in waves and The Mississippi River actually did flow backwards. The damage nearly wiped New Madrid off the face of the Earth.

UALR PhD candidate Okbar Al-Qadi showed the reason damage can be so intense. Sandy areas do a much poorer job of absorbing quake vibration than rocky ones so the waves travel farther and cause more damage. In much of eastern Arkansas, that's nearly all we've got.

Those at UALR say they discovered a fault line south of Marianna. About 5,000 years ago, they say a pretty good sized earthquake here caused what they call sand blows, like little volcanoes of sand and water shooting up through the ground because of the intense shaking and pressure.

That is still a concern around the New Madrid Fault itself, but the bigger worry is sandy sediment giving way beneath roads, homes and other buildings across the state.

Dr. Haydar Al-Shukri at the earthquake center at UALR says the number of earthquakes isn't higher this year; the quakes are just striking more populated areas. And they're all unrelated since they're on different fault lines. Still, Dr. Al-Shukri believes we have a 50 percent chance of experiencing a 6 or 6.5 quake somewhere along the New Madrid in the next 15 years.

"The more we wait, the more the probability increases because we know stress is accumulating. We see it because minor activity takes place along this fault," says Dr. Al-Shukri.

So what would a big New Madrid quake do?

If a 6.5 magnitude quake happened at the southern part of the seismic zone in Marked Tree, northeast Arkansas would see major structural damage, loss of power and water, injuries, and death. In Little Rock, you'd see structural damage, especially in places built on soft sediment close to the river or in the eastern part of the city.

"We don't know what bridges will be up, we don't know what roads will be passable," says David Maxwell. "A lot of the efforts at first will be assessing what has actually happened."

The Arkansas Department of Emergency Management (ADEM) would jump into action to respond to earthquake damage. In fact, it's preparing for a 7.0 quake scenario. Emergency responders drill regularly and ADEM is making sure agencies have enough resources like food, water and medical supplies to meet all the needs. A massive 2011 drill marking the 200th anniversary of the first New Madrid quake happens next year involving all eight states that could be impacted by a New Madrid quake.

On top of the drills, retrofitting projects are happening at bridges and buildings across the state, particularly in the northeast, to stabilize these structures and protect them from an earthquake's vibrations.

"Our attitude is that we've got to get prepared now because it could happen tomorrow," says Maxwell.

Until then, the Earthquake Center and the Arkansas Geological Survey are in the process of placing more seismic stations across Arkansas, a total of 14, to monitor activity. While an increase in activity doesn't always happen before a major quake, pre-shocks in the hours before a quake can sometimes provide a life-saving warning. But experts say, make no mistake a big one is coming someday.

"This is not just my interpretation of what's going to be happening. This is the interpretation of almost all geologists and seismologists who study the region," says Dr. Al-Shukri.

What you can do at home to be prepared?

  • Keep several days of food and water stockpiled in your home.
  • Minimize damage and injury in your house by securing bookshelves, hot water tanks and other heavy items to your walls.
  • Move heavy objects around your home from top shelves to lower ones to keep them from falling and hurting anyone.
  • Find out if your home has earthquake coverage since most homeowners' policies in Arkansas don't cover it.
Very good video on the NMFZ here at source--click me





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(Twilight Saga commentary)
http://throughgoldeneyes.blogspot.com/
(Coming soon---Volcano Watch!)

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Thursday, April 29, 2010

[Volcano_Vista_HS] VVHS Announcements--Thursday, April 29, 2010



Good Morning Hawks

Today is April 29th

 

Do you want something fun to do this summer?  Do you need community service for clubs or scholarship applications? Find out about summer volunteer opportunities at the Albuquerque Biopark which includes the zoo, aquarium, botanic gardens, and Tingley Beach.  Information will be given on Friday, April 30 at lunch in Ms. Pace’s room (A201).

 

“Fashion Show Models and Fashion Club: We will be showing The 2010 Prom Fashion Show DVD today at lunch in Mrs. Bergsten's room, F225. Anyone is welcome to come and view the show. A copy of the DVD will cost two dollars. Please have cash when you place your order. Copies of the DVD will be available within a week.”

 

Students summer school registration has begun.  If you are in need of credit recovery, please see your counselor for registration packets.

 

Tryout for the Talons Dance Team! Tryouts will be held after school Tuesday May 11 through Friday May 14. Tryout packets are available in the main office.

 

Attention all boys interested in playing soccer for Volcano Vista next year.  There will be a meeting on May 6 â€"Thursday â€" at lunch in room A130. 

 

SENIORS: If you are planning on being involved in the Dodge Ball Tournament,  meet with Mrs. Jones during lunch on Thursday in E203

 

Attention all Avian Actors, all cast and crew for All I Really Need to Know I Learned in Kindergarten and Into the Woods:  Please stop by Mr. Finn's room, G-108, for your invitation to the third annual Drama Honors Banquet.  The banquet will take place Thursday, May 6.  Please reserve your spot ASAP. 

 

Thespians:  There is a general Thespian meeting this Friday.  Be sure to attend!  There will be a lot of information given regarding the banquet, and we will be holding officer elections for the 2010-2011 school year.  DO NOT MISS THIS MEETING! 

 

Attention ALL current, active Thespians!  Are you interested in becoming a Thespian Officer for the 2010-2011 school year?  If you want to run on the ballot, talk to Mr. Finn TODAY.  Voting will begin this Friday in G-108.  

 

Hawks Helping Hands, your verification forms are due on Friday in the library.  Be sure you get them into the box on the circulation desk by 2:30.

 

Overdue and fine notices went out during second period yesterday.  Over 400 students have overdue books...some from August and September!  Let's get everything turned in and paid for so you won't have an extra hour or two at registration next fall.

 

SENIORS: You don't want to miss out!!!

The Film Club will be taking orders at the Senior Picnic on set for Monday, May 3rd at 5:30pm. Cash and checks welcome.  Checks need to be written to to Volcano Vista High School. Remember:

 

$10 per Senior Video if you pick it up

$15 per Senior Video if we mail it

 

This is your opportunity to purchase the official Senior Video. Look for the Film Club table.

 

Students, some AP exams have not been paid for.  If you are interested in taking the English Literature and Composition, US History, Physics B, Calculus AB, or World History exams, we will accept your payment on a first-come, first-serve basis in the Health Academy, E216.  Please see Mrs. Abernathy if you have any questions. 

 

Seniors if you have received any scholarships please stop by your academy office and fill out the scholarship form so that we may add it to the program for the Honors Assembly.

 

Prom tickets are on sale today at lunch in the activities office for $25. You must have a student ID to purchase a ticket. If you plan to bring a guest, you may only bring one guest, please have the guest form filled out and signed by the appropriate person. You will need this form at the time you buy the tickets. Please remember to bring your ticket and ID to the dance.

 

There are 2 more days left to purchase your yearbook for $65.00. We have only 75 books left to sell. Stop by activities to buy your book now! The last day to purchase a yearbook for $65.00 will be Friday. Yearbooks will be distributed on May 3rd to seniors at their picnic and during lunch on May 4th to underclassmen. You must have your student ID to pick up your book.

 

Athletics:

 

The softball team beat St.Pius yesterday 14 to 7 and 17 to 8. Behind the hitting of Alex Marquez, Shaylin Brown, Monique Cotinola and Katera Eltsosie the team is the 2010 District Champions!!!  Congratulations to the softball team.

 

Track is participating in their District meets on Saturday in Belen.

 

Both tennis teams will be participating in their District tournaments Friday and Saturday.

 

It’s great to be a hawk!



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[Geology2] Latest observations at Eyjafjallajökull 04/29/2010




Latest observations at Eyjafjallajökull – Iceland volcano pictures

Written by: Editor on 29th April 2010
Latest observations at Eyjafjallajökull – Iceland volcano pictures

The eruption site was seen clearly during yesterday's overflight.

Eruptive activity in the northern ice cauldron remains similar to conditions during the preceding four days. A volcanic crater has formed in the south-western corner of the cauldron. Erupted material from the vent continues to accumulate on the flanks of the crater. The rim of the volcanic crater is ~50 m lower than the surrounding ice cauldron. Volcanic spatter was observed from the vent, with ejected lava reaching heights of 100-200 m.

Unstable plumes of ash rise regularly from the vent.

Lava continues to flow to the north under the ice cap, advancing ~1 km from the crater. Depressions in the ice-surface have formed due to lava being in contact with ice; these features have enlarged considerably since 24 April. The surface of Gígjökull is grey due to ash deposition; likewise, the north-western flank of Eyjafjallajökull is black in appearance.

Booming

sounds were reported yesterday from Hvolsvöllur, 32 km west of the eruption site.

The above is based on status report issued collectively by IMO and the Institute of Earth Sciences.

An update on events and prospects, including ash forecasts as well as earlier information, can still be found through links in red at IMO's front page. Check also "Forecaster's remark" (to the right), if relevant. For earlier news of both eruptions, click 2010.

Icelandic Meteorological Office
http://en.vedur.is/

Pictures from volcano – Eyjafjallajökull here
http://mbl.is/myndasafn/safn/1660/



Source


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[californiadisasters] Anniversary Reminder



Reminder from:   californiadisasters Yahoo! Group
 
Title:   1992 Los Angeles Riots
 
Date:   Thursday April 29, 2010
Time:   5:00 pm - 5:00 pm
Repeats:   This event repeats every year.
Location:   Los Angeles
Notes:   Between 5 P.M. and 6 P.M. on this date in 1992 the Los Angeles Riots began in two places.
One was out in front of Parker Center (LAPD HQ) in downtown L.A. where an at-first peaceful protest turned violent.
The other location was at the corner of Florence and Normandy when an angry crowd developed and was not immediately dispersed by the LAPD who withdrew instead.
The situation subsequently cascaded out of control from both locations ultimately lasting three days.
Over the three days of rioting 53 people were killed and 2,000 injured and nearly a billion dollars in losses were incurred, most if it in the neighborhoods of the rioters.
 
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Yahoo! Shopping:   Browse Yahoo! Shopping Gift Guide
 
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[californiadisasters] Fairfield Fire Kills 4 Injures 2



A Apartment Fire in Fairfield CA, has killed 4 children and injured 2 adults
 
 
 
Mike


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[californiadisasters] el mayor CuCAPAH EARTHQUAKE





Figure 1: Location of recent earthquakes (shown as red stars) in the northern Baja area; map provided by Dr. Sue Beck, Univ. of Arizona; the "beach balls" represent the type of motion associated with the earthquakes with black signifying compression, and white signifying tension; the yellow diamonds represent the location of the Arizona Broadband Network run by a consortium consisting of the Arizona Geological Survey, University of Arizona, Arizona State and Northern Arizona University.

el mayor CuCAPAH EARTHQUAKE
magnitude 7.2 earthquake
JERI J. YOUNG, AZGS RESEARCH GEOLOGIST

On April 4th, 2010, Baja California, Mexico shook violently from a Mw 7.2 earthquake that occurred  about 40 miles south of the U.S/Mexico border at a depth of approximately six miles (Figure 1).  In Mexacali, Mexico, there were two earthquake-related deaths, more than 200 injured, a city-wide power outage and substantial structural damage to some buildings.  The historic center of Calexico, California, was closed as a number of building were flagged with serious structural damage. 

The earthquake was felt hundreds of miles from its epicenter—as far north as Santa Barbara, California, and as far east as Scottsdale, Arizona.

According to the US Geological Survey, the main shock coincides with the southeast segment of the Laguna Salada fault. In 1892, an event on this same fault produced an M 7.2 event.  In this region, plate movement occurs along a series of northwest trending strike-slip faults that parallel the San Andreas Fault system to the north.  The Pacific Plate is moving  approximately 45 mm per year to the northwest with respect to the North American plate.   

The US Geological Survey shake map, which integrates near-real time ground motion and shaking intensity, shows a NW-SE envelope of violent to severe shaking in the Laguna Salada basin west of the Cucapa Mountains. Very strong to strong shaking was observed as far north as El Centro, California, with strong to moderate shaking extending east to Yuma, Arizona.  People throughout southern and central Arizona reported feeling the ground shake and observed sloshing swimming pools and shaking objects in and outside of their homes (Figure 2, below). 

There have been at least 708 aftershocks as of April 6th, most of which lie within a northwest-southeast trending 75 km long swath that parallels faults found in the area, and extends at least 6 miles north into the United States (Figure 3, below).   Foreshocks were recorded during the later part of March, including a moderate sized Mw 5.5 foreshock that occurred just minutes before the mainshock.

Broadband seismometers of the Arizona Integrated Seismic Network (AISN), a consortium comprising the Arizona Geological University, Arizona State University, Northern Arizona University, and University of Arizona , recorded the large temblor (Figures 4, below).  The April 4th Baja earthquake should be a reminder that ground-shaking associated with fault systems outside the state, and sometimes within the state, can occur in Arizona. 

Figure 2: Shake map produced by the U.S.G.S.; the Yuma area experienced moderate shaking, while Phoenix and other areas felt weak to light shaking; star represents the epicenter of the April 4th earthquake.

 

 

Figure 3: The April 4th, 2010 Sierra El Mayor main shock shown as red a blue star, aftershocks shown in red and foreshocks shown as blue circles;; earthquakes associated with the December 2009 series are shown in green and the remaining 2009 seismicity shown in black.  Large faults are represented as black lines; Image courtesy of the Southern California Seismic Network.

Figure 4: Seismogram from several Arizona seismometers.(From Global Seismology and Tectonics, Geosicences Dept, University of Arizona)

 

 

 

 

 

MORE PHOTOS of el mayor - cucapah earthquake

Photography by Danny Ashcraft (CEO Western CNC, Inc.) near Mexicali, Mexico

Photographs by Francisco Bernal (Mexican Section of the International Boundary and Water Commission - IBWC) near Mexicali, Mexico

 Source


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(Coming soon---Volcano Watch!)

>^,,^<  


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[Geology2] Glyptodonts in arizona a saga of supercontinents, sea-floor spreading, savannas, and sabertooth cats




Glyptodonts in arizona
a saga of supercontinents, sea-floor spreading, savannas, and sabertooth cats

DAVID D. GILLETTE, COLBERT CURATOR OF VERTEBRATE PALEONTOLOGY, MUSEUM OF NORTHERN ARIZONA

"The Great American Biotic Interchange" has not yet gained popular acclaim as a household expression in Arizona. Nor have many in our good state realized that Arizona played a critical role in this exchange. Still fewer know that a critical component of that exchange were animals called "glyptodonts, or that events at both poles influenced their immigration and evolution.  

In every gift shop with "dinosaur" toys, observant shoppers are likely to find toy models of glyptodonts. Two shown here are Glyptotherium and Doedicurus. Among the many lineages of glyptodonts in South America, perhaps the most bizarre is Doedicurus, with the massive mace at the end of the bony tube at the rear half of the tail.

Glyptodonts were 4-legged tanks, pseudo-tortoises with fur, protected by a rigid shell composed of tightly interlocking plates an inch thick and more. The largest glyptodonts weighed a ton, ate plants, and probably spent a lot of time in water, along shores of lakes and streams. They resembled their distant relatives, the armadillos, but the fossil record of these two groups spans tens of millions of years indicating they diverged early in the history of their branch of placental mammals.

Nearly as big as a Volkswagen Beetle, and about the same shape, glyptodonts were abundant in South America where they originated. Among the first paleontologists to study glyptodonts was Charles Darwin. I often wonder what the influence of his observations of these strange armadillo-like beasts had on the formulation of his theories of evolution.

Glyptotherium texanum restoration by artist Victor Leskyk.  The snout is conjectural. An alternate interpretation of the face is shown in the inset. The heavy, armored carapace consisted of interlocking plates of bone that were generally hexagonal, and covered in life by scales. Bristles projected from hair follicles in the bony plates. The simple tail was covered by heavy rings of bony plates.

The glyptodont shell was so rigid that the coalesced armor plates are often found still connected, occasionally as a complete carapace like the one shown in main-image above. There are even records of indigenous South American people using a fossil carapace for shelter—these shells were large, to be sure, but they surely made for crowded if not solitary refuges! The carapace and tail in main-image (above) is the gigantic South American genus Doedicurus, famous for the bony tube that encased the vertebrae of the rear half of the tail, and the horrific mace that could have dealt a death blow to a would-be predator. The spikes are not mounted on this tail, but the attachment surfaces are easy to recognize.

The arrival of the "glyptodont fauna" of southeastern Arizona 2 million years ago heralded the mixing of faunas that till then had never come in contact: eventually mammoths, mastodons, horses, deer, camels, dogs, and cats spread populations from their North American homelands, to South America where their competitors were all marsupial mammals and odd placental mammals. At the same time, some of those odd placental mammals such as anteaters, armadillos, glyptodonts, and ground sloths from South America invaded the northern savannahs of that continent, then the coastal plains of Central America and soon thereafter, into Mexico and North America. Glyptodonts and ground sloths should be in the vocabulary of every native Arizonan, because these strange animals were among the Arizonans that lived beside mastodons, mammoths, saber-tooth cats, lions, extinct horses, camels, llamas and more in the North American Ice Age, right here in the desert Southwest. It's desert here now, but 2 million years ago, these animals lived in well-watered savannas and riparian forests that later dwindled in the Ice Ages and left little but these fossils as testament to wet times gone by. This was the "glyptodont fauna," so named because these armored tanks were at times the most abundant large animal in this bizarre landscape.

Left side of the skull and jaws of the South American glyptodont, Glyptodon. Snout or no snout: premaxillary and nasal bones on the glyptodont skull are greatly reduced, indicating a very blunt, short-faced head. A bar that extends downward on the side of the face from the cheekbones anchored chewing muscles for grinding food, and might have anchored snout muscles that formed a muscular trunk, like that of tapirs shown in the previous figure. Photograph courtesy of Gaston Design.

The story of these pilgrims from South America involves two supercontinents, three continents, two oceans, an island chain, an isthmus, glaciers, and sea level. It begins 200 million years ago early in the Mesozoic Era, during the time of dinosaurs. Earth's midsection was mostly ocean, and two huge landmasses occupied the northern hemisphere (Laurasia) and the southern hemisphere (Gondwana). The breakup of Gondwana began then, a process that produced the Gondwana continents: Antarctica, Australia, New Zealand, Africa, South America, India, and Madagascar. South America, the homeland of our armored immigrants, separated from Africa, Australia separated from one side of Antarctica and South America from the other side, and eventually Antarctica took its present, familiar polar position. The other land masses slipped away, in the process creating new ocean landscapes: the Atlantic, Pacific, and Indian Oceans, and with the final isolation of Antarctica, the Antarctic Sea. In broad perspective, the Antarctic Sea and Antarctica became Earth's refrigerator, affecting temperatures of ocean water through ocean currents that variously heated and cooled the seas and the atmosphere.

Following its isolation from Antarctica and other southern continents most vertebrate animals on the island continent of South America had evolved for at least 63 million years in isolation, more closely related to Australia's mammals than those in North America. (One marsupial, the opossum, invaded North America in the Ice Age and occupies most of Mexico and southern United States today.)

A juvenile Glyptotherium texanum being attacked by a predatory cat, by artist Victor Leshyk. As shown in these two interpretations, this hapless juvenile might have had the head tucked under, or it might have faced its deadly adversary nose to nose before succumbing to the smarter, more powerful predator. This interpretation is based on the pair of holes in the skull shown in the next illustration.

The key to the story here is the connection between the two continents, today called the Isthmus of Panama. Geologically speaking, the Isthmus is very young. Until only a few million years ago the oceans now called the Pacific and Atlantic were one.  There was no land separation, so marine animals and plants could freely mix eastward and westward, with little isolation. But with movement of the Caribbean Plate in the late Cenozoic, the two continents became connected, forever isolating the two oceans but uniting the land areas where land dwelling animals and plants could mix. This was evolution at its finest: the sudden mixing of animals and plants in both directions, tests of their adaptations and survival. Some groups on both continents invaded the Isthmus beginning around 3 million years ago. A few of those groups managed to expand their populations through the Isthmus and into the other continent. Glyptodonts, as ungainly and awkward as they appear, were among the most adaptable from South America. Their populations shifted northward through the Isthmus and into Central America. When sea level fluctuations began about the same time, coastal savannas opened up as sea level dropped by as much as 100 meters, and then closed off when sea level rose again. One major cause of these sea level changes was fluctuation of glaciers in Antarctica and the arctic region of North America.

One remarkable skull of Glyptotherium texanum from southeastern Arizona has two elliptical puncture holes, interpreted as the consequence of a fatal attack by a large predatory cat. This skull is on display at the American Museum of Natural History in New York City. Arrows point to the two puncture holes.


















South America's isolation as an island continent had come to a close. Glyptodonts had become abundant, diverse, and widespread. Mixing of faunas and floras tested adaptability of large organisms and smaller ones alike: all parts of the habitats were affected, from decomposer organisms in soils and parasites that infected plants and animals, through the reigning ecosystems. Glyptodonts surely carried unique parasites, and plants they preferred were almost certainly different when they were isolated in South America. Glyptodont evolution north of South America took a new twist. The earliest population, known mainly from southeastern Arizona, became dominant members of the ecosystem. They were small as glyptodonts go, weighing perhaps a quarter to half a ton. These were the progenitors of at least two more species in the United States, and two other species known from single specimens in Mexico. But they all belong in the genus Glyptotherium (groove-toothed beast). Our early Arizona species bears the unfortunate (for us) name Glyptotherium texanum (named for glyptodonts found in west Texas with a population that extended from Florida to Arizona), but the descendant species Glyptotherium arizonae had adults nearly twice as large, and weights exceeding a ton. These two species occupied an ecological setting in Arizona that was at least seasonally wet, with abundant vegetation and little resemblance to the modern Sonoran Desert of the American Southwest.

Artist's interpretation of the carapace (shown as cut-away) and skeleton of Glyptotherium arizonae, based on skeletons from southeastern Arizona. The thoracic vertebrae, sacral vertebrae, and hips were fused into a single support framework that bore the massive weight of the shell and body. This interpretation was prepared by artist Larry Isham from the Smithsonian Institution.

A third species had evolved from the earlier ancestors by the end of the Pleistocene and occupied only the Gulf Coast and southern Atlantic Coastal Plain. This was Glyptotherium floridanum, named for fossils found in Florida. Two others are known from Mexico: Glyptotherum mexicanum and Glyptotherium cylindricum, the only species with a name that lacks a geographic connotation.

Glyptodonts had a rigid shell composed of very thick armor plates of bone in the dermis. These plates interlocked during growth and protected the sides and back; the belly was not armored and was the most vulnerable part of the body. Some have suggested that glyptodonts could simply tuck the legs beneath the "shell" to protect the belly, much in the same fashion as their distant relatives, the armadillos (which instead  have a flexible shell composed of rings of armor that allow them to curl up for protection). In adult glyptodonts the only flexible parts of the shell were on the sides toward the front. Otherwise the shell was as rigid as a tortoise shell, and just as cumbersome.

The mounted carapace and internal skeleton of Glyptotherium texanum from southeastern Arizona, with the skeleton of a nine-banded armadillo for reference. The side of the carapace facing the viewer was not preserved, thus providing a window into the interior of the shell. This skeleton is in the American Museum of Natural History, New York.

The armor plates were covered in skin and scales that had a rosette pattern formed by grooves in the bone. The general pattern for Glyptotherium was one central figure surrounded by six to eight peripheral figures. Details of that general pattern allow a fair measure of confidence in identification of the five species when skulls and skeletons are not available. Two or three deep pits in the grooves on each plate housed follicles of modified hairs, or bristles that served a sensory function, quite a valuable asset for an animal that could not see its sides or back. The tail was covered in plates, too, in a series of flexible rings that completely enclosed the tail vertebrae, muscles, and blood vessels. In Glyptotherium the tail ended in a terminal set of rings with only moderate ornamentation; in one South American group, the tail was armored with a defensive mace that would have deterred attackers like saber-tooth cats.

Six scutes from the carapace of the Gulf Coast glyptodont, Glyptotherium floridanum from the Late Pleistocene of Florida. These plates interlocked along their sides and made the shell rigid. These are about an inch in thickness. Arrows point to follicles that housed bristles that served a sensory function. The rosette patterns are separated by grooves that housed blood vessels which nourished the scales that covered the plates in the same pattern.



















Additional armor plates protected the top of the head, but they were not impenetrable. One skull of a juvenile Glyptotherium texanum from southern Arizona has a pair of elliptical holes in the top of the cranium. These holes are the right size and spacing to lead to the conclusion that this individual was killed by a large cat with a sudden blow to the head that punctured the armor plates and skull roof. That skull is presently on display at the American Museum of Natural History in New York City.

In the interpretation here by artist Victor Leshyk, two possible attack modes are presented: one with the glyptodont's head tucked under, the other with the head in a normal standing position. In either case, the attacker had to have a large gape, and probably attacked from the front.  We cannot determine which fossil cat produced these holes, but it's clear that this glyptodont met a quick personal extinction.

Glyptodont teeth were simple three-lobed cylindrical prisms without enamel. Grinding motions of the jaws flattened the crowns of the teeth, probably worn down by silica from grasses. They had neither canines nor incisors. The shortened front of the head might have had a flexible proboscis or trunk, like that of sea cows or tapirs.  My interpretation of the head is a short proboscis, like the interpretation here by artist Victor Leshyk, but others have proposed a longer one, and still others have claimed the face was blunt and lacked any prehensile anatomy like the inset in the Leshyk artwork. These armored herbivores likely grazed on grasses and soft plants, perhaps even along shorelines or in water.

Glyptodont legs were short, heavily-built, and squat. Glyptodonts could probably outrun a tortoise, but few other animals in its ecosystem. Although running to escape predators might not have been very effective, swimming might have been an avoidance strategy. Most paleontologists consider the glyptodont habitat as savanna, but most glyptodont faunas include the South American capybara, a mainly aquatic rodent somewhat larger than a beaver, indicating proximity to water. I have often imagined glyptodonts "snorkeling" in water, their buoyant shells partly submerged and the only part of the head breaking water the upturned proboscis.

Closeup of coalesced scutes in the carapace of Glyptotherium texanum. Individual scutes are generally hexagonal, a shape that made the carapace inflexible in adults when these plates were completely fused. The patterns on the scutes can be used for identification of species.

Glyptodonts disappeared from Arizona by the middle of the Pleistocene, and their populations became restricted to the Gulf Coast at the end of the Pleistocene, around 11,000 years ago. Their extinction coincides roughly with the extinction of most of the megafauna: mammoths, mastodons, camels, llamas, horses, ground sloths, sabertooth cats, giant bison, giant armadillos, and many smaller species. Paleontologists debate the cause of this seemingly abrupt extinction, which happened about the same time that humans entered North America from Asia. Most fall into one of two camps: overkill by the earliest Americans, or climate deterioration. A recent, highly popularized version of the deteriorating climate hypothesis is the assertion that a bolide from space (part of a comet or an asteroid) impacted the earth somewhere with such force that it affected climate and habitats, and soon thereafter caused the extinction of these giants from the Ice Age.

The glyptodont saga came to an end with their extinction, but research continues on these beasts from the past. Paleontologists in South America and North America alike have resurrected these poorly studied mammals in the past decade to discover a fruitful line of study.  In Arizona, some real fossils of glyptodonts are on display at the Arizona Museum of Natural History in Mesa. These bones are from the early, small species, Glyptotherium texanum, from southeastern Arizona.

When I travel in southern Arizona, in my mind's eye I see glyptodonts, mammoths, mastodonts, camels, horses, ground sloths, saber-tooth cats, armadillos, anteaters, and tortoises. I also imagine early people here, and in South America where a direct association has been documented, living beside these armored marvels, and even hunting them.


Source

Also, in this issue, there is a photographic tour of the Superstition Mtns. Click here to see it.




--
(Gars O'Higgins Station penguins)
http://wiinterrr.blogspot.com/
http://penguinnewstoday.blogspot.com/
http://penguinology.blogspot.com/
(Twilight Saga commentary)
http://throughgoldeneyes.blogspot.com/
(Coming soon---Volcano Watch!)

>^,,^<  


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