Retreating Yukon glacier caused a river to disappear

The massive Kaskawulsh Glacier in northern Canada has retreated about a mile up its valley over the past century.

A Sept. 2, 2016 aerial photo shows the meltwater stream along the toe of Kaskawulsh Glacier, seen on the left, that is 
diverting fresh water from one river to the other [Credit: Dan Shugar/University of Washington Tacoma]

Last spring, its retreat triggered a geologic event at relatively breakneck speed. The toe of ice that was sending meltwater toward the Slims River and then north to the Bering Sea retreated so far that the water changed course, joining the Kaskawulsh River and flowing south toward the Gulf of Alaska.

This capture of one river's flow by another, documented in a study led by the University of Washington Tacoma and published in Nature Geoscience, is the first known case of "river piracy" in modern times. "Geologists have seen river piracy, but nobody to our knowledge has documented it happening in our lifetimes," said lead author Dan Shugar, a geoscientist at the University of Washington Tacoma. "People had looked at the geological record -- thousands or millions of years ago -- not the 21st century, where it's happening under our noses."

River piracy, also known as stream capture, can happen due to tectonic motion of Earth's crust, landslides, erosion or, in this case, changes in a glacial dam. The new study documents one of the less-anticipated shifts that can occur in a changing climate.

Shugar and co-authors Jim Best at the University of Illinois and John Clague at Canada's Simon Fraser University had planned fieldwork last summer on the Slims River, a geologically active system that feeds Kluane Lake in the Yukon. When they arrived in August, the river was not flowing. River gauges show an abrupt drop over four days from May 26 to 29, 2016.

By late summer, "there was barely any flow whatsoever. It was essentially a long, skinny lake," Shugar said. "The water was somewhat treacherous to approach, because you're walking on these old river sediments that were really goopy and would suck you in. And day by day we could see the water level dropping."

Images captured by the European Space Agency’s Sentinel2 satellite in 2015 and 2016 show a dramatic drop in the Slims 
River’s flow. The receding toe of Kaskawulsh Glacier is seen at the bottom. Kluane Lake can be seen at the top of the 
2016 image. Water now flows east and then south via the Kaskawulsh River [Credit: European Space Agency]

The research team puzzled about what to do next. They got permission to use their mapping drone to create a detailed elevation model of the glacier tongue and headwater region. The resulting paper is a geological postmortem of the river's disappearance.

"For the last 300 years, Slims River flowed out to the Bering Sea, and the smaller Kaskawulsh River flowed to the Gulf of Alaska. What we found was the glacial lake that fed Slims River had actually changed its outlet," Shugar said. "A 30-meter (100-foot) canyon had been carved through the terminus of the glacier. Meltwater was flowing through that canyon from one lake into another glacial lake, almost like when you see champagne poured into glasses that are stacked in a pyramid."

That second lake drains via the Kaskawulsh River in a different direction than the first. The situation is fairly unique, Shugar said, since the glacier's toe was sitting on a geologic divide.

Clague began studying this glacier years ago for the Geological Survey of Canada. He observed that Kluane Lake, which is Yukon's largest lake, had changed its water level by about 40 feet (12 meters) a few centuries ago. He concluded that the Slims River that feeds it had appeared as the glacier advanced, and a decade ago predicted the river would disappear again as the glacier retreated.

"The event is a bit idiosyncratic, given the peculiar geographic situation in which it happened, but in a broader sense it highlights the huge changes that glaciers are undergoing around the world due to climate change," Clague said.

A close-up view of the ice-walled canyon at the terminus of the Kaskawulsh Glacier, with recently collapsed ice blocks. 
This canyon now carries almost all meltwater from the toe of the glacier down the Kaskawulsh Valley 
and toward the Gulf of Alaska [Credit: Jim Best/University of Illinois]

The geologic event has redrawn the local landscape. Slims River crosses the Alaska Highway, and its banks were a popular hiking route. Now that the riverbed is exposed, Dall sheep from Kluane National Park are making their way down to eat the fresh vegetation, venturing into territory where they can legally be hunted. With less water flowing in, Kluane Lake did not refill last spring, and by summer 2016 was about 3 feet (1 meter) lower than ever recorded for that time of year. Waterfront land, which includes the small communities of Burwash Landing and Destruction Bay, is now farther from shore. As the lake level continues to drop researchers expect this will become an isolated lake cut off from any outflow.

On the other hand, the Alsek River, a popular whitewater rafting river that is a UNESCO world heritage site, was running higher last summer due to the addition of the Slims River's water.

Shifts in sediment transport, lake chemistry, fish populations, wildlife behavior and other factors will continue to occur as the ecosystem adjusts to the new reality, Shugar said.

"So far, a lot of the scientific work surrounding glaciers and climate change has been focused on sea-level rise," Shugar said. "Our study shows there may be other underappreciated, unanticipated effects of glacial retreat."

The Kaskawulsh Glacier is retreating up the valley because of both readjustment after a cold period centuries ago, known as the Little Ice Age, and warming due to greenhouse gases. A technique published in 2016 by UW co-author Gerard Roe shows a 99.5 percent probability that this glacier's retreat is showing the effects of modern climate change.

"I always point out to climate-change skeptics that Earth's glaciers are becoming markedly smaller, and that can only happen in a warming climate," Clague said.

Source: University of Washington [April 17, 2017]

byUnknown

in Canada, Climate Change, Ecosystems, Natural Heritage, North America

April 17, 2017

Retreating Yukon glacier caused a river to disappear

The massive Kaskawulsh Glacier in northern Canada has retreated about a mile up its valley over the past century. A Sept. 2, 2016 aerial pho...

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14,000 year old mammoth tusk discovered hidden in Alaska wilderness

In the heart of Interior Alaska, at a recently discovered archaeological site, scientists have uncovered a huge mammoth tusk dating back 14,000 years. Objects made of ivory and used for hunting were also identified.

The tusk was discovered buried in soil sediments at the Holzman archaeological site 
[Credit: Adelphi University]

The Holzman site was first discovered in 2015, hidden in the Alaska wilderness. Initial excavations revealed a series of late Pleistocene occupations containing remains of large mammal fauna, mammoth ivory fragments and stone tools buried in sediment deposits.

During the 2016 excavation season, a member of the team discovered the large mammoth tusk buried in the soil, about 1.5 metre underground. The tusk is nearly 5ft-long (140cm), and appears to be well preserved.

Radiocarbon dating suggests it is 14,000 years old, but it was sent to a lab at Adelphi University for further analyses.

Hunters or scavengers?

The scientists, are investigating who the first Americans were and when humans first settled in North America.

They hope the study of the tusk will help them settle important questions about the first Americans and about whether they overlapped with mammoths at the Holzman site.

The newly discovered tusk is 14,000 years old but so far evidence of human activity at the site only date back to 13,700 years ago.

The site lies at the heart of Alaska Interior [Credit: Adelphi University]

"It's possible that humans found the tusk, which dated back to a few hundred years before their time, and used it to create their ivory tools", Brian Wygal, a co-principal investigator of the excavation and an associate professor of anthropology at Adelphi University, told IBTimes UK.

"One of the most important questions that we want to answer is whether the tusk was scavenged by these prehistoric people or if they hunted the mammoth down – in which cases mammoths and humans would have cohabited at the Holzman site 14,000 years ago".

The analyses of the tusk could provide an answer. The scientists are planning more isotope analyses as well as a study of ancient DNA to see if they can find traces that the mammoth was hunted. Depending on how well preserved the tusk is, they might also be able to establish how old it was when it died, its sex and what its diet was.

New excavations this summer might further help them determine if humans already lived at the site 14,000 years ago. "We may for instance find other parts of the mammoth which will indicate that it was consumed by people 14,000 years ago", Wygal said.

The research could also shed a new light on how mammoths became extinct in the US. If the analyses revealed the large mammals were hunted down, this will provide more evidence that humans might have played a role in their demise. The subject of how mammoths went extinct remains a source of heated debate among scientists.

Author: Lea Surugue | Source: International Business Times [April 13, 2017]

byUnknown

in Alaska, Americas, Archaeology, Early Mammals, Fossils, North America

April 15, 2017

14,000 year old mammoth tusk discovered hidden in Alaska wilderness

In the heart of Interior Alaska, at a recently discovered archaeological site, scientists have uncovered a huge mammoth tusk dating back 14,...

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The dangers of being a saber-toothed cat in Los Angeles 12,000 years ago

Saber-toothed cats that roamed Los Angeles 12,000 years ago had many injuries to their shoulders and backbones that likely occurred when they killed large herbivore prey such as bison and horses, UCLA biologists report in the journal Nature Ecology and Evolution.

In this illustration, saber-toothed cats pursue a bison. UCLA biologists say the cats sustained injuries to their backs 
and shoulders, likely as a result of attacks on their prey [Credit: Mauricio Anton]

Their Southern California contemporary, the dire wolf, was more likely to suffer from injuries to the head, neck, ankles and wrists, the researchers report.

"The difference in neck injuries between the two animals is dramatic," said lead author Caitlin Brown, a UCLA doctoral student in ecology and evolutionary biology. "The dire wolves had many neck injuries clustered together that could have resulted from the wolves being dragged by thrashing prey, as we see in modern wolves. In contrast, the saber-toothed cat has almost no neck or head injury, which implies that they were avoiding damage to their precious teeth."

Brown and another UCLA doctoral student in ecology and evolutionary biology, Mairin Balisi, analyzed more than 35,000 bones from saber-toothed cats and dire wolves over six months at the La Brea Tar Pits' George C. Page Museum. The researchers found injuries on 4.3 percent of all saber-toothed cat bones and 2.8 percent of all dire wolf bones.

Like modern gray wolves, dire wolves—which "are not made-up beasts for 'Game of Thrones,'" Brown said—were predators that caught and killed prey with their jaws. By contrast, saber-toothed cats (Smilodon fatalis), a species without close modern descendants, are thought to have ambushed large prey using powerful back and forelimb muscles to pull down and position the animals for killing bites. Saber-toothed cats were heavier than dire wolves, and are believed to have used their large forelimbs to pin down their prey.

"Consequently, we expected injuries in saber-toothed cats would likely be concentrated in the shoulder, anterior ribcage and spine, while those of dire wolves were likely to be more evenly distributed across all four limbs," said senior author Blaire Van Valkenburgh, a UCLA professor of ecology and evolutionary biology. "In addition, head injuries were likely to be more common in the dire wolves because they were at risk of being kicked while biting the hind­quarters during a chase. Caitlin and Mairin's analyses supported these conclusions."

While previous studies of these animals have demonstrated that injuries likely occurred during fierce battles, the UCLA biologists are the first scientists to study enough bones to determine how frequently the injuries occurred.

The finding that saber-toothed cats sustained more frequent injuries than dire wolves suggests that the cats faced a much greater risk of injury over their lifetimes. It is thought that this is because the cats killed relatively larger prey and may have done so alone, rather than as part of a group. Instead of exhaust­ing their prey through a long pursuit, the cats ambushed prey at a short distance and immobilized them using their massive forelimbs before killing the prey with precisely positioned bites, the researchers said.

"Dire wolves hunted in packs, which were essentially a running set of jaws," Van Valkenburgh said. "They had to do everything with their mouths. So we expected to see injuries where they were kicked in the head, and maybe injuries in the limbs, either by being kicked or by tripping during a hunt."

Saber-toothed cats are not tigers, Balisi noted, and are only distantly related to modern cats.

The biologists studied only trauma, inju­ries that likely resulted from hunting. This trauma included fractures that had healed, severe or chronic muscle strain, and osteoarthritis.

Author: Stuart Wolpert | Source: University of California, Los Angeles [April 14, 2017]

byUnknown

in Early Mammals, Fossils, North America, Palaeontology, USA

April 14, 2017

The dangers of being a saber-toothed cat in Los Angeles 12,000 years ago

Saber-toothed cats that roamed Los Angeles 12,000 years ago had many injuries to their shoulders and backbones that likely occurred when the...

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Moabosaurus discovered in Utah's 'gold mine'

Move over, honeybee and seagull: it's time to meet Moabosaurus utahensis, Utah's newly discovered dinosaur, whose past reveals even more about the state's long-term history.

BYU researcher Brooks Britt with the newly discovered Moabosaurus, on display 
at BYU's Museum of Paleontology [Credit: Jaren Wilkey, BYU]

The Moabosaurus discovery was published this week by the University of Michigan's Contributions from the Museum of Paleontology. The paper, authored by three Brigham Young University researchers and a BYU graduate at Auburn University, profiles Moabosaurus, a 125-million-year-old dinosaur whose skeleton was assembled using bones extracted from the Dalton Wells Quarry, near Arches National Park.

BYU geology professor and lead author Brooks Britt explained that in analyzing dinosaur bones, he and colleagues rely on constant comparisons with other related specimens. If there are enough distinguishing features to make it unique, it's new.

"It's like looking at a piece of a car," Britt said. "You can look at it and say it belongs to a Ford sedan, but it's not exactly a Focus or a Fusion or a Fiesta. We do the same with dinosaurs."

BYU researcher Brooks Britt with the newly discovered Moabosaurus, on display 
at BYU's Museum of Paleontology [Credit: Jaren Wilkey, BYU]

Moabosaurus belongs to a group of herbivorous dinosaurs known as sauropods, which includes giants such as Brontosaurus and Brachiosaurus, who had long necks and pillar-like legs. Moabosaurus is most closely related to species found in Spain and Tanzania, which tells researchers that during its time, there were still intermittent physical connections between Europe, Africa and North America.

Moabosaurus lived in Utah before it resembled the desert we know -- when it was filled with large trees, plentiful streams, lakes and dinosaurs. "We always think of Moab in terms of tourism and outdoor activities, but a paleontologist thinks of Moab as a gold mine for dinosaur bones," Britt said.

In naming the species, Britt and his team, which included BYU Museum of Paleontology curator Rod Scheetz and biology professor Michael Whiting, decided to pay tribute to that gold mine. "We're honoring the city of Moab and the State of Utah because they were so supportive of our excavation efforts over the decades it's taken us to pull the animal out of the ground," Britt said, referencing the digs that began when he was a BYU geology student in the late '70s.

A previous study indicates that a large number of Moabosaurus and other dinosaurs died in a severe drought. Survivors trampled their fallen companions' bodies, crushing their bones. After the drought ended, streams eroded the land, and transported the bones a short distance, where they were again trampled. Meanwhile, insects in the soils fed on the bones, leaving behind tell-tale burrow marks.

"We're lucky to get anything out of this site," Britt said. "Most bones we find are fragmentary, so only a small percentage of them are usable. And that's why it took so long to get this animal put together: we had to collect huge numbers of bones in order to get enough that were complete."

BYU has a legacy of collecting dinosaurs that started in the early 1960s, and Britt and colleagues are continuing their excavation efforts in eastern Utah. Moabosaurus now joins a range of other findings currently on display at BYU's Museum of Paleontology -- though, until its placard is updated, it's identified as "Not yet named".

"Sure, we could find bones at other places in the world, but we find so many right here in Utah," Britt said. "You don't have to travel the world to discover new animals."

Author: Brooke Adams | Source: Brigham Young University [April 13, 2017]

byUnknown

in Dinosaurs, Fossils, North America, Palaeontology, USA

April 13, 2017

Moabosaurus discovered in Utah's 'gold mine'

Move over, honeybee and seagull: it's time to meet Moabosaurus utahensis, Utah's newly discovered dinosaur, whose past reveals even ...

Read More

Could a Colorado earthquake have been triggered by dinosaur extinction impact?

Researchers have found signs of fault displacement at well-known rock outcrops in Colorado that mark the end-Cretaceous asteroid impact that may have hurried the extinction of the dinosaurs. They will present their results in a poster at the 2017 Seismological Society of America's (SSA) Annual Meeting.

Longs Canyon area of Colorado's Trinidad Lakes State Park [Credit: WikiCommons]

Norm Sleep of Stanford University and colleagues suggest that the impact, which occurred near the Yucatán Peninsula of Mexico, could have generated massive seismic waves that triggered earthquakes as far away as Colorado, in the center of a tectonic plate where no previous fault had existed.

Sleep and his colleagues found evidence for the fault in two areas in Colorado's Trinidad Lakes State Park, where a layer of iridium generated by the asteroid impact clearly marks the boundary between Cretaceous and Tertiary-age rocks, at the time of the dinosaurs' extinction about 65 million years ago. At the Long's Canyon and Madrid Canyon roadcuts, "there is a fault that slipped about a meter at the time of the impact," Sleep said. "It offset the material below the impact layer but not above, but it's not something that would be obvious to the casual observer."

The researchers suggest that the Colorado earthquake may have been as large as magnitude 6. Very strong seismic waves from the impact -- much larger than would be generated by a regular earthquake, Sleep said -- would be necessary to trigger an earthquake in this location, in the middle of a tectonic plate with no previous faults.

The end-Cretaceous asteroid strike, however, could have generated ground velocities of a meter or two per second, Sleep said. "The ground would be moving up and down and sideways like a ship in a strong storm."

At the time of the earthquake, the area in Colorado was a swampy, delta-like environment, crossed by large braided streams that ran from the young Rocky Mountains. Sleep and his colleagues saw signs that the earthquake had diverted a small stream in the area.

This summer, the researchers will be checking in New Mexico near the Raton Basin for further signs of intraplate quakes that may have been triggered by the asteroid strike.

Source: Seismological Society of America [April 11, 2017]

byUnknown

in Dinosaurs, Earth Science, Geology, North America, Palaeontology, USA

April 11, 2017

Could a Colorado earthquake have been triggered by dinosaur extinction impact?

Researchers have found signs of fault displacement at well-known rock outcrops in Colorado that mark the end-Cretaceous asteroid impact that...

Read More

Food webs entangle humans in complex relationships with animals, crops and the environment

Reconstructed food webs from the Ancestral Puebloan southwestern United States show the complexity and interconnectedness of humans, other animals, crops and the environment, in an area of uncertain climate and resources, according to researchers, who think climate change and human decisions then, may shed light on future human choices.

Square Tower House in Mesa Verde National Park [Credit: Nate Crabtree]

"As southwestern archaeologists, we know that Ancestral Puebloan people were intrinsically connected to the environment," said Stefani Crabtree, postdoctoral fellow in human behavioral ecology in the Department of Anthropology, Penn State. "But, most food webs have omitted humans."

Traditionally, food webs, while they map the interaction of all the animals and plants in an area, usually do not emphasize the human component. Crabtree and colleagues created a digital food web that captures all categories of consumers and consumed, can be defined for specific time periods and can also represent food webs after major food sources or predators disappear from the area. If an area suddenly becomes devoid of deer or humans or corn, for example, a food web of that situation can show where predators went to find prey, or which prey thrived for lack of a predator.

These knockout food webs -- webs missing a specific predator or prey -- show the changes and pressures on the food sources substituted for the missing ones, or the changes that occur when pressure is removed by removing a major consumer. The researchers report the results of their study in the Journal of Archaeological Science.

"When people show up in the area around A.D. 600 they bring corn," said Crabtree. "It takes a while for critters to get used to it, but eventually, everything that eats vegetation, eats corn and prefers it."

Humans bringing corn into an area is a major disruption of the existing food web. Planting corn means clearing fields to displace whatever plants and animals were there, creating a high-energy plant source of food and switching plant eaters to the preferred higher-calorie food source.

In the American Southwest, the Ancestral Puebloan people eventually preyed on their deer population enough so that they deer were no longer a reliable source of food. To compensate for this, they began to domesticate turkeys for food. Turkeys need to be fed corn if they are captive and that competes with corn for human consumption. At this time, corn made up 70 to 80 percent of Ancestral Puebloans' food and so feeding turkeys altered the food web.

A sample food web with red nodes representing primary producers, orange nodes primary consumers, yellow-orange 
nodes omnivores, true-yellow nodes are true carnivores. This draft food web was created with the program 
Network3D from foodwebs.org [Credit: Stefani Crabtree, Penn State]

To create the food web, the team identified all the common, noninvasive species in the area. They then added species that were found in archaeological sites, but were absent from the modern lists. In some food webs, components are identified by their function, so all humming birds are considered flying pollinators, but in this case each type of humming bird received its own place in the web, linked to what it ate and what, if anything, ate it. This produced a very complicated web, but supplied exceptional redundancy.

"In the insect world it is harder to get at the data," said Crabtree. "We have not been able to get at good databases so we aggregate at the functional level -- pollinators or bloodsuckers for example."

The exception to individual web entries then are invertebrates -- insects, spiders, snails, etc. -- that were classified by their function. Invertebrates are organized to the level of order and then grouped by function. With insects, for example, the researchers would group butterflies and moths that pollinated and sipped nectar, together in one group.

The overall food web had 334 nodes representing species or order-level functional groups with 11,344 links between predator and prey.

The researchers realize that there are differences in the environment between now and the Ancestral Puebloan period, but many things, such as pinon-juniper woodlands and sage flats are the same. Enough similarity exists for this approach to work.

The team did not produce just one overall food web, but also food webs corresponding to three archaeological locations and three time periods of Ancestral Pueblo occupation in the area -- Grass Mesa Pueblo for Pueblo I, Albert Porter Pueblo for Pueblo II and Sand Canyon Pueblo for Pueblo III. They began with using archaeological assemblages from these sites incorporating all human prey and all human predators into the food web. Then they included the prey of the primary prey of humans and then predators of these human-prey species. Prey, in this case, includes animals, insects and plants.

A coyote preying on an entire clutch of baby rabbits in Boulder County, CO. [Credit: Mindy Wilkinson]

When creating knockout food webs, the researchers included only those species that were found in reasonable quantities in the archaeological assemblages at those times.

"Knockout food webs are one of the best ways to understand how people interact with the environment," said Crabtree. "Because we can remove something, predator or prey, and see what would happen."

When major changes in climate variables such as drought, heat and lack of snowpack are factored in, the balance in the food web may become unstable. When food becomes scarce, most mobile creatures, animals and insects move to another location. During the time of the Ancestral Puebloans, this was possible and eventually, these people moved to the area of the Rio Grande in New Mexico and other places in New Mexico and Arizona.

"We didn't have a long-term plan during the 600 years of Ancestral Pueblo habitation in the Mesa Verde region," said Crabtree. "We don't have a long-term plan today either. We don't even have a four-year plan. Some people are pushing us to look closely at climate change."

In the past, people migrated, said Crabtree. Unless we figure out better strategies, where are we going to migrate out to? We do not have a place to go, she said.

What people plant and eat has a great effect on the environment and on ecosystems. In the end, those choices will impact human survival, according to the researchers.

This work is part of a collaboration of researchers creating resolved food webs from a variety of places. Crabtree believes that she can compare this project to others that include humans in other geographical areas to help understand ecosystems with humans in them.

Author: A'ndrea Elyse Messer | Source: Penn State University [April 10, 2017]

byUnknown

in Americas, Archaeology, Climate Change, Ecosystems, Environment, North America, USA, Wildlife

April 10, 2017

Food webs entangle humans in complex relationships with animals, crops and the environment

Reconstructed food webs from the Ancestral Puebloan southwestern United States show the complexity and interconnectedness of humans, other a...

Read More

Archaeologists unearth ancient pithouse in British Columbia's Fraser Canyon

An ancient pithouse at Bridge River in the Fraser Canyon that spanned about 1,500 years and included 17 distinct layered floors ending at the European fur-trade era is providing unique insight into the lives of early First Nations, archaeological research reveals.

A new archaeology study is revealing fantastic details about an aboriginal pithouse at Bridge River 
in the Fraser Canyon spanning about 1,500 years and including 17 distinct layered floors 
ending at the European fur-trade era [Credit: PNG]

“For the entire Pacific Northwest region, this is the best documented, long-lived aboriginal house in the archaeological record,” confirmed Anna Marie Prentiss, a professor of anthropology at the University of Montana in Missoula. “We have exquisite detail, with all these floors.”

About every 20 years, the Bridge River people built a new roof on the pithouse and a new layer of dirt floor as a living area. Each layer or floor reveals details specific to that time period, be it the rise and fall of salmon stocks, the creation of artwork such as pendants, the trade in iron and beads, the processing of deer pelts, even the raising of domestic dogs for human consumption.

The excavation site is about two kilometres upstream of the Fraser River confluence next to the current Bridge River village. Band chief Susan James says her people — 457 members, about half of them living on reserve — had a general knowledge of their ancestors but not to the level of detail unveiled by archaeologists. “We’ve found it fascinating, it’s all been learning for us,” she said. Band tours of the site are available to the public.

Prentiss explained that Pithouse 54 was excavated over four seasons. Her book, The Last House at Bridge River, is about to be published.

“We realized this house had something special, an extraordinary record,” she said.

The dig found 157 dog bones on various floors, several featuring cut marks from defleshing. Although the Bridge River dog is related to Siberian dogs, it was considered its own unique breed. The thinking is that younger dogs up to 2.5 years old risked being eaten. Older dogs were typically kept as family pets and for work, including for transport and as a warning system for the village.

Dogs were also thought to be a delicacy at Bridge River, said Prentiss, who obtained her doctoral degree from Simon Fraser University. “When (explorer) Simon Fraser visited the Lillooet people (1808) he was served a feast of dog meat. That kind of says it all right there.”

The pithouse was not occupied consecutively for 1,500 years. It was abandoned three times, including about 1,000 years ago. A decline in salmon bones suggest fewer fish migrating through the Fraser Canyon during an era known as the Medieval Warm Period.

The house also expanded in size and shape, at times rectangular or round, over the generations. At its peak, it might have housed 30-40 people.

Pithouses were badgered into the ground to provide extra warmth in winter and cooling in summer, reflecting the more extreme climates of the Lillooet area.

The top layer of the pithouse is thought to span the late fur-trading period from 1835 to 1858. Researchers found numerous artifacts of the period, including: Venetian glass beads painted red, green and white; an iron horseshoe; a finger ring; machine-made bone buttons; and three stone spindle whorls, suggesting weaving yarn from dog or mountain goat hair.

Researchers also found heaps of deer bones, burned rocks from boiling, 250 hide scrapers, and 135 stone arrow points, evidence that aboriginals were trading skins with fur traders, a period when beaver populations had collapsed.

“The fur-trade material lets us see what life was like just before the onslaught of the gold rush,” Prentiss says. “We’ve never had that kind of insight.”

The pithouse, which is part of a larger settlement, contains no evidence from the gold-rush starting in 1858 in the area, she said. After that, aboriginals are thought to have lived in cabins.

Prentiss is presenting her findings at the Society for American Archaeology conference, which opens Wednesday in Vancouver and is expected to attract 5,000 visitors through this weekend.

Author: Larry Pynn | Source: Vancouver Sun [April 07, 2017]

byUnknown

in Americas, Archaeology, Canada, Indigenous Cultures, North America

April 07, 2017

Archaeologists unearth ancient pithouse in British Columbia's Fraser Canyon

An ancient pithouse at Bridge River in the Fraser Canyon that spanned about 1,500 years and included 17 distinct layered floors ending at th...

Read More

Remains of insects from bed bug genus found at oldest human habitation site in Oregon

A cave in southern Oregon that is the site of some the oldest preserved evidence of human activity in North America was also once home to not-too-distant cousins of the common bed bug.

The subfossil remains of 14 cimicids also known as bed bugs were recovered during archaeological
 investigations of the Paisley Five Mile Point Cave site in south-central Oregon 
[Credit: Martin E. Adams/Paleoinsect Research]

In research to be published next week in the Entomological Society of America's Journal of Medical Entomology, a pair of archaeologists describe remains found in caves near Paisley, Oregon, that represent the oldest specimens of insects from the genus Cimex ever found, ranging between 5,100 and 11,000 years old.

The remains were identified as relatives of the bed bug, Cimex lectularius, but they were "not the bed bug we all know and love from hotel rooms," says Martin E. Adams of Paleoinsect Research and co-author on the study with Dennis L. Jenkins of the Museum of Natural and Cultural History at the University of Oregon. The species in the Paisley Five Mile Point Caves (Cimex pilosellus, Cimex latipennis, and Cimex antennatus) are all parasites of bats.

The abdomen of a female Cimex pilosellus found in the Oregon cave
[Credit: Martin E. Adams/Paleoinsect Research]

Previously, the oldest remains of "cimicids" ever found were just 3,500 years old, found in Egypt in 1999, meaning the remains found at the Paisley Caves are the oldest Cimex specimens by a wide margin, and they raise some interesting questions for researchers about how cimicids have interacted (or not) with humans in the past.

Cimex lectularius and Cimex hemipterus are the two bed bug species that are known to parasitize humans, widely believed to have adapted to that role thousands of years ago when humans shared caves with bats in Europe, Asia, and Africa. The species found in the Oregon caves, however, never made that jump, and Adams says it's unclear why not.

The Cimex antennatus specimen dated back 5,100 years, while others ranged from 9,400 to nearly 11,000 years old 
[Credit: Martin E. Adams/Paleoinsect Research]

"Were the cimicid populations too small to establish themselves outside the caves, or were the host populations too small?" Adams says. "Given that Paisley Caves was only a seasonal occupation area for human hunter-gatherers, did the humans move around too much, or were the bugs not able to withstand the environment outside the caves for very long? Or, were there other constraints involved? I'm working on these last few archaeological questions right now."

The identification of the three Cimex species may also offer some clues to climactic trends during the eras they were dated to, Adams says. Cimex antennatus, for instance, tends to favor the warmer climates of California and Nevada. "The presence of warm-tolerant cimicids in the caves, such as Cimex antennatus, may suggest that climatic conditions at Paisley Caves 5,100 years ago were similar to what Cimex antennatus enjoys today in its current range."

Source: Entomological Society of America [April 04, 2017]

byUnknown

in Americas, Archaeology, Fossils, North America, USA

April 04, 2017

Remains of insects from bed bug genus found at oldest human habitation site in Oregon

A cave in southern Oregon that is the site of some the oldest preserved evidence of human activity in North America was also once home to no...

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Study reveals 10,000 years of genetic continuity in northwest North America

A study of the DNA in ancient skeletal remains adds to the evidence that indigenous groups living today in southern Alaska and the western coast of British Columbia are descendants of the first humans to make their home in northwest North America more than 10,000 years ago.

Researchers are analyzing DNA from ancient individuals found in southeast Alaska, coastal British Columbia, Washington
state and Montana. A new genetic analysis of some of these human remains finds that many of today's indigenous peoples 
living in the same regions are descendants of ancient individuals dating to at least 10,300 years ago 
[Credit: Julie McMahon, University of Illinois]

"Our analysis suggests that this is the same population living in this part of the world over time, so we have genetic continuity from 10,000 years ago to the present," said University of Illinois anthropology professor Ripan Malhi, who led the study with University of Chicago postdoctoral researcher John Lindo; Penn State University biology professor Michael DeGiorgio; Rosita Worl, the director of the Sealaska Heritage Institute in Juneau, Alaska; and University of Oklahoma anthropology professor Brian M. Kemp.

The findings, reported in the Proceedings of the National Academy of Sciences, also suggest that these early American peoples had a complex population history, the researchers report.

The new work comes on the heels of earlier studies of ancient Americans that focused on mitochondrial DNA, which occurs outside the nucleus of cells and is passed only from mothers to their offspring.

"Mitochondrial DNA just traces the maternal line - your mother's mother's lineage - so, you're missing information about all of these other ancestors," said Lindo, the first author on the paper. "We wanted to analyze the nuclear genome so we could get a better assessment of the population history of this region."

The team looked at genomic data from Shuká Káa (Tlingit for "Man Before Us"), an ancient individual whose remains - found in a cave in southeastern Alaska - date to about 10,300 years ago. They also analyzed the genomes of three more individuals from the nearby coast of British Columbia whose remains date to between 6,075 and 1,750 years ago.

"Interestingly, the mitochondrial type that Shuká Káa belonged to was also observed from another ancient skeleton dated to about 6,000 years ago," Kemp said. "It seems to disappear after that. The nuclear DNA suggests that this is probably not about population replacement, but rather chance occurrence through time. If a female has no children or only sons, the mitochondrial DNA is not passed to the next generation. As a male, Shuká Káa could not have passed on his own mitochondrial DNA; he must have had some maternal relatives that did so."

The researchers turned their attention to nuclear DNA, which offers a more comprehensive record of a person's ancestry.

"DNA from the mitochondria and Y chromosome provide unique yet sometimes conflicting stories, but the nuclear genome provides a more comprehensive view of past events," DeGiorgio said.

"The data suggest that there were multiple genetic lineages in the Americas from at least 10,300 years ago," Malhi said.

The descendants of some of those lineages are still living in the same region today, and a few are co-authors on the new study. Their participation is the result of a long-term collaboration between the scientists and several native groups who are embracing genomic studies as a way to learn from their ancestors, said Worl, who is Tlingit, Ch'áak' (Eagle) moiety of the Shangukeidí­ (Thunderbird) Clan from the Kawdliyaayi Hít (House Lowered From the Sun) in Klukwan, Alaska.

"We supported DNA testing of Shuká Káa because we believed science ultimately would agree with what our oral traditions have always said - that we have lived in southeast Alaska since time immemorial. The initial analysis showed the young man was native, and now further studies are showing that our ancestral lineage stems from the first initial peopling of the region," said Worl, who also is an anthropologist. "Science is corroborating our oral histories."

Author: Diana Yates | Source: University of Illinois at Urbana-Champaign [April 04, 2017]

byUnknown

in Americas, Anthropology, Canada, Genetics, Indigenous Cultures, North America, USA

April 04, 2017

Study reveals 10,000 years of genetic continuity in northwest North America

A study of the DNA in ancient skeletal remains adds to the evidence that indigenous groups living today in southern Alaska and the western c...

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Archaeologist explains innovation of 'fluting' ancient stone weaponry

Approximately 13,500 years after nomadic Clovis hunters crossed the frozen land bridge from Asia to North America, researchers are still asking questions and putting together clues as to how they not only survived in a new landscape with unique new challenges but adapted with stone tools and weapons to thrive for thousands of years.

A collection of Clovis point replicas and casts in the archaeology lab at Kent State University
[Credit: Kent State University]

Kent State University's Metin Eren, Ph.D., director of archaeology and assistant professor in the Department of Anthropology in the College of Arts and Sciences, and his colleagues are not only asking these questions but testing their unique new theories. They want to better understand the engineering, techniques and purposes of Clovis weapon technologies. Specifically, they study stone projectile points, such as arrowheads and spear points, made by flint knapping, the ancient practice of chipping away at the edges of rocks to shape them into weapons and tools.

In their most recent article published online in the Journal of Archaeological Science, Eren and his co-authors from Southern Methodist University (Brett A. Story, David J. Meltzer and Kaitlyn A. Thomas), University of Tulsa (Briggs Buchanan), Rogers State University (Brian N. Andrews), Texas A&M University and the University of Missouri (Michael J. O'Brien) explain the flint knapping technique of "fluting" the Clovis points, which could be considered the first truly American invention. This singular technological attribute, the flake removal or "flute," is absent from the stone-tool repertoire of Pleistocene Northeast Asia, where the Clovis ancestors came from.

Metin Eren, director of archaeology and an assistant professor of anthropology in Kent State University's College of Arts 
and Sciences, demonstrates the ancient weapon-making technique of flint knapping a point in his laboratory 
on the Kent Campus [Credit: Kent State University]

Archaeologists have debated for years as to why the Clovis added this flute feature to their points. Basically, it is a thin groove chipped off at the base on both sides, perhaps first made by accident, which logically makes it very thin and brittle. However, after several types of testing, the researchers have reported that this thinning of the base can make it better able to withstand and absorb the shock of colliding with a hard object, such as the bone of a mastodon or bison.

This fluted point turned out to be an invention that allowed these colonizers to travel great distances with some confidence that their weaponry would hold up at least long enough until they could find the next rock quarry to make new points.

"It was risky and couldn't have been easy to learn how to do this effectively," Eren explained. "Archaeological evidence suggests that up to one out of five points break when you try to chip this fluted base, and it takes at least 30 minutes to produce a finished specimen. So, though it was a time-consuming process and risky technique, successfully fluted Clovis points would have been extremely reliable, especially while traveling great distances into unknown regions on a new continent. They needed points that would hold up and be used over and over again."

In their article, the researchers compared standardized computer models of fluted and unfluted points, as well as experimental "real-world" test specimens, and found that the fluted-point base does in fact act as a "shock absorber," increasing point robustness and ability to withstand physical stress via stress redistribution and damage relocation. In other words, upon impact, the brittle base of the spearhead crumples and absorbs some energy, which prevents fatal breaks elsewhere on the point so it could be reused.

"It's amazing to think that people 12,000 years ago were flaking shock absorbers and engineering stone weapons in a way that it took 21st century modern engineering to figure out," Eren said.

"As engineers, we don't typically get to work with archaeologists, but this project has allowed us the exciting opportunity to provide additional tools from engineering mechanics to explore how fluting affects the behavior of Clovis points," Story said.

Source: Kent State University [April 04, 2017]

byUnknown

in Americas, Archaeology, Canada, North America, USA

April 04, 2017

Archaeologist explains innovation of 'fluting' ancient stone weaponry

Approximately 13,500 years after nomadic Clovis hunters crossed the frozen land bridge from Asia to North America, researchers are still ask...

Read More