MAMMOTHS AND MASS EXTINCTION

Much ado about something - New evidence points to a celestial end for the wooly mammoth and many large mammals.

A swarm of comets that smacked North America 12,900 years ago wiped out the wooly mammoth and early Native American cultures, according to a soil study released Thursday.

The report in the journal Science focuses on tiny "nanodiamonds," crystals tied to past comet impacts, at six sites across the continent in a soil layer dated to the start of a 1,300-year-long ice age.

Geologists and archaeologists have long argued about what caused the extinction of dozens of large North American "megafauna" species, such as saber-toothed cats and mammoths. Was it environmental conditions, human intervention, competition for resources or a combination of factors? It seems a commet is to blame.

"What we're reporting is consistent with a major cosmic impact that had major consequences for the environment and Earth's climate," says study leader Douglas Kennett of the University of Oregon in Eugene.

"A swarm of comets" or carbon-rich meteorites either delivered or created the nanodiamonds in a fiery impact, the study suggests. The report relies on photomicrograph analyses of soil samples from Arizona, Minnesota, Oklahoma, South Carolina and two Canadian sites. Photomicrography captures images seen through a microscope.

"This is the 'smoking gun' evidence for a massive impact event 12,900 years ago that triggered the (ice age) and the extinction of the megafauna," says nuclear scientist Richard Firestone of the Lawrence Berkeley (Calif.) National Laboratory, who was not part of the study.

If true, the impact date coincides with the abrupt halting of deposits of "Clovis" Native American artifacts, distinctively fluted tools and arrowheads. Dozens of large animal species vanished then in North America. Kennett and other impact researchers have suggested a continent-wide wildfire may have contributed to the extinction of large North American creatures. In Europe, there were disruptions to the prehistoric culture and the demise there of species such as the cave bear and Irish elk.

Some scientists urge caution.

"We simply do not have conclusive evidence that nanodiamond materials aren't everywhere at many times," says geologist Nicholas Pinter of Southern Illinois University in Carbondale. "Tons of meteorite dust falls to Earth every year, after all."

Although more than 30 North American species died out about 12,900 years ago, about 50 large species died out a few centuries later in South America, and on some unpeopled Caribbean islands, species such as sloths survived an additional 6,000 years, says archaeologist Stuart Fiedel, author of Prehistory of the Americas. "Humans, not extraterrestrial objects," best explain the staggered extinctions in the New World, he says.

Kennett says future studies will show evidence of the nanodiamonds from Europe and further afield 12,900 years ago. Impact shock waves, debris and wildfires sparked by comets breaking apart in the atmosphere would have hit North America hardest, he says, but the effects would have been felt worldwide.

Fossil Mammals are the theme of the Eighth BC Paleontological Symposium being held at the University of British Columbia, May 14-18, 2009. Come and learn about the great mammals that roamed North America and hear the debates on their demise. Visit www.bcfossils.ca for more information

The story references an Irish Elk. A 12,000 year old specimen in the collections at UBC will be on display at the Symposium.

Ref: Dan Vergano

VOLCANIC DEMISE: THE TRIASSIC-JURASSIC EXTINCTION

Located as they are in Canada’s most active earthquake zone, the Queen Charlotte Islands have had their share of shake-ups and scourings. Many of the Islands’ hillsides are scarred by slides. But the rock beneath speaks of an even more violent past. Very few people know that the rock in the Queen Charlottes holds the key to a catastrophic event from eons ago.We’ve heard tales and seen images of the cataclysmic damage caused by meteriorites smashing into the Earth’s surface.

Until recently, it was a meteorite impact that was blamed for the worldwide Triassic/Jurassic Mass Extinction. This wholesale dying out of species occurred some 200 million years ago. New evidence challenges the meteorite theory. Experts now believe that tectonic forces may have caused hundreds of volcanoes around the world to erupt simultaneously. The subsequent showers of volcanic ash would have altered the composition of the atmosphere dramatically and plunged the world into near total darkness for years until it settled from the sky.

The picture painted of the sun flickering fitfully through inky clouds, paling against the torrents of glowing lava, while everywhere life is smothered, poisoned, or starved, rivals the most apocalyptic imaginings of Hollywood or religion. We know from worldwide evidence that the extinction was dramatic and affected upwards of 70% of the world’s biota.

Perhaps counterintuitively, for one might think of water as a refuge from fire, smoke, and lava, it was marine lifeforms that suffered the most. This is particularly well documented in the rocks of the Queen Charlottes, especially at Kennecott Point and Kunga Island.

Radiolarian microfossils – tiny, siliceous, single-celled microrganisms – tell the tale. In the Upper Triassic rocks, which predate the extinction by about 10 million years, radiolarians are preserved in hundreds of forms. Just above them, in the early Jurassic rock layers laid down about the time of the great die-offs, only a fraction of the previous number of forms are represented. The more recent Jurassic rock shows a rebound of radiolarian diversity (though of course, in different forms) — a diversity which continues to flourish and expand in today’s oceans.

Radiolarian microfossils – tiny, siliceous, single-celled organisms – tell the tale. These wee timekeepers have been living in the world’s oceans for about 600 million years. Because they occur in continuous and well-dated sequences of rock in the Queen Charlottes, these exquisitely beautiful microfossils act like a yardstick, helping geologists accurately date rock from around the globe.

In the Upper Triassic rocks, which predate the extinction by about 10 million years, radiolarians are preserved in hundreds of forms. Just above them, in the Early Jurassic rock layers laid down about the time of the great die-offs, only a fraction of the previous number of forms are represented.

The Queen Charlottes are most noted for their fossil ammonites, the coiled cousins to modern day nautilus. These perfectly preserved specimens tell of a deep water environment and warm tropical seas. The younger Jurassic rock shows a rebound of radiolarian diversity (though of course, in different forms) - a diversity that continues to flourish and expand in today’s oceans.

COASTAL WOLVES: GENETIC DIFFERENCES

Have you ever seen headless salmon littering the banks of rivers and streams during spawning season? Most who have generally blame our local bears for this selective dining. The real culprits are coastal wolves who gorge themselves on the nutrient-rich brains, leaving the rest to scavengers.

It seems this preference for fish and a redish tinge to their pelts set our local wolves apart. Coastal wolves, from Alaska and Vancouver Island, have not only adapted to their local environment but have evolved into something altogether new.

Think Darwin's finches.

Researchers from the Raincoast Conservation Foundation have published in this month's Journal of Biogeography, that our coastal wolves, "are like no other wolves." Well, we could have told them that, but no one listens until a paper gets published.

Grey wolves (Canis lupus), coastal wolves and our household pets (Canis lupus familiaris) share a common ancestry but at some point our coastal wolves have broken from the pack. With genetic differences that, "are striking and their ecology is very, very different."

So it seems everything old is new again.

CEDAR: LIFEBLOOD TO AN ISLAND

The arrival of cedar, called “Tsuuaay” by the Haida, had profound effects on the material culture of the Haida (Approx 4000 BC). Once they were able to build canoes to fish year round for local halibut, red snapper and ling cod and increased their access to sea mammals, they were granted a bit of freedom. They still enjoyed their relationship to the spawning cycle of the salmon but cedar gave them options. The cedar bent wood box, a genius idea in food conservation and storage, allowed them to store food for the winter. Often carved with exquisite detail, the cedar bent wood box became art, status and lifebood.

CARIBOO LIGHT

BOWRON LAKE CIRCUIT

VICIOUS MEAT-EATING HUNTER TRACKED TO AFRICA

While evidence of 95-million year old therapods from Africa is quite scare making one think that each fragment would be treated like gold, this was not the case the first evidence of Carcharodontosaurus iguidensis, a newly described dinosaur from the Cenomanian of Nigeria and published in this months issue Journal of Vertebrate Paleontology.

This fellow almost had the misfortune of going extinct twice! Tooth fragments collected by Charles Depéret and J. Savornin in 1927 were misplaced before this meat-eater could ever be described and when additional material was collected in Egypt in the 1930’s it also came to an unfortunate end. Sent to German paleontologists in Munich to describe, the fossils were lost in the rubble as Allied Forces bombed the building in which they were housed during WW II.But the rocky history and luck of Carcharodontosaurus iguidensis improved when paleontologist in residence at National Geographic, Paul Sereno found cranial material on a Moroccan dig in 1996.

:: THE EVIDENCE MOUNTS...

That find combined with material collected the following year in Nigeria were studied by Sereno, along with Steve Brusatte, a paleobiologist at the University of Bristol in England, and Paul Sereno and determined to be a new species, not C. saharicus as originally thought. The massive skull, neck and bone fragments belonged to Carcharodontosaurus iguidensis, one of the largest dinosaurs ever found. Carcharodontosaurus differs from C. saharicus, his smaller Saharan coursin, both in the maxilla and braincase.

Carcharodontosaurus iguidensis walked upright and was a massive beast, weighing in at an impressive 3.2 tons. Extending upwards of 14 meters (44 ft), nearly as long as Tyrannosaurs, alive today they could easily peer through a second story window - a menacing thought as they were well-equipped hunters with sizable teeth.The climate was much warmer when Carcharodontosaurus iguidensis and C. saharicus roamed the Earth and the seas much higher. Beyond geographic distance, the raised sea level may have been what set these therapods apart.
:: SHALLOW SEAS...

Shallow seas separated what is now Morocco and Nigeria and this separation may have prompted the development of the unique characteristics define the two species.. Perhaps more abundant prey and favorable conditions allowed Carcharodontosaurus iguidensis to grow to their huge size while C. saharicus remained a smallish 1.6 meters (5.2 ft). While not a reptile, C. saharicus has been compared with modern Crocodylia, another group who first appeared in the Cretaceous, as they share similar inner ear anatomy and cerebrum size relative to total brain.

Like many therapods prior to the 1930’s, the African species were originally misgrouped into the genus Megalosaurus. Paleontologist Ernst Stromer von Reichenbach corrected this error. After taking a closer look at their anatomy, particularly their dentition, he renamed them Carcharodontosaurus in 1931 citeing their "mainly Carcharodon-like teeth", which were "not recurved, almost bilaterally symmetrical but with convex edges”

The Carcharodontosaurids were a group of gigantic carnivorous carcharodontosaurid dinosaurs that lived 98 to 93 million years ago. Carcharodontosaurus means 'shark lizard', after the shark genus Carcharodon, an apt handle as they were ominous killers with enormous jaws and long, serrated teeth, some as long as eight inches.

References:

Brusatte, S. and Sereno, P.C. (2005). "A new species of Carcharodontosaurus (Dinosauria: Theropoda) from the Cenomanian of Niger and its implications for allosauroid phylogeny." Journal of Vertebrate Paleontology, 25: 40A.

Brusatte, S.L. and Sereno, P.C. (2007). "A new species of Carcharodontosaurus (dinosauria: theropoda) from the Cenomanian of Niger and a revision of the genus." Journal of Vertebrate Paleontology, 27 (4).

Deparet, C. and Savornin, J. (1927). "Sur la decouverte d'une faune de vertebres albiens a Timimoun (Sahara occidental)." Comptes Rendus, Academie du Sciences, Paris, 181: 1108-1111.Larsson, H.C.E. (2001). "Endocranial anatomy of Carcharodontosaurus saharicus (Theropoda: Allosauroidea) and its implications for theropod brain evolution." Pp. 19-33 in D.H.

Tanke & K. Carpenter (eds.), Mesozoic Vertebrate Life. Indiana University Press, Bloomington.Stromer, E. (1931). "Wirbeltiere-Reste der Baharijestufe (unterestes Canoman). Ein Skelett-Rest von Carcharodontosaurus nov. gen." Abhandlungen der Bayerischen Akademie der Wissenschaften, Mathematisch-naturwissenschaftliche Abteilung, 9(Neue Folge): 1–23.

KAYAKING LAKE ISAAC

GLOBAL WARMING: THE TROPICAL EOCENE

In 2004, a scientific crew braced the cold and the odds to extract a sediment core from 400m below the seabed of the Arctic Ocean. The core showed that Fifty-five million years ago, deep in the Eocene, the North Pole was ice-free and enjoying tropical temperatures. It also told us that the temperature of the ocean was 20C, instead of the coolish –1.5C we see today… a truth that is hard to imagine with all the hype around global warming.

The bottom end of that core helped explain the fossils found at Eocene sites around British Columbia, species commonly seen in more tropical environments today.

The warmer temperatures seen at McAbee and around the globe were recorded in the core sample and reveal evidence for a global event known at the Palaeocene-Eocene Thermal Maximum. Back in the Eocene, a gigantic emission of greenhouse gases was released into the atmosphere and the global temperature warmed by about 5C.

While the bookends of the geologic time scale slide back and forth a wee bit, the current experts in the geologic community set the limits to be 33.9 +_ 0.1 to 55.8 +_ 0.2 million years ago. The fossil record tells us that this part of British Columbia and much of the Earth was significantly warmer around that time, so warm in fact that we find temperate and tropical plant fossils in areas that now sport plants that prefer much colder climes, or as is the case in the Arctic, snow and ice.

The Okanagan Highlands is an area centred in the Interior of British Columbia, but the term is used in a slightly misleading fashion to describe an arc of Eocene lakebed sites that extend from Smithers in the north, down to the fossil site of Republic Washington. The grouping includes the fossil sites of Driftwood Canyon, Quilchena, Allenby, Tranquille, McAbee, Princeton and Republic. These fossil sites range in time from Early to Middle Eocene, and the fossil they contain give us a snapshot of what was happening in this part of the world because of the varied plant fossils they contain..

While the area around the Interior of British Columbia was affected. McAbee was not as warm as some of the other Middle Eocene sites, a fact inferred by what we see and what is conspicuously missing.

In looking at the plant species, it has been suggested that the area of McAbee had a more temperate climate, slightly cooler and wetter than other Eocene sites to the south at Princeton, British Columbia and Republic and Chuckanut, Washington. Missing are the tropical Sabal (palm), seen at Princeton and the impressive Ensete (banana) and Zamiaceae (cycad) found at Republic and Chuckanut, Washington.

While we are the likely culprits of much of the warming of the Arctic today, natural processes operating in the not too distant past have also resulted in significant temperature fluxuations on a world-wide scale.

COY BOY AT THE DOG PARK: ANGUS

ANOTHER DAY IN PARADISE