The End of the Dinosaurs

Bernard O'Connor, August 1995

A violent continental summer thunderstorm one early Saturday evening threw us together. The taxi driver taking three of us to Billings airport on a boiling hot afternoon jokingly told us that the airline we'd be travelling on was locally called Big Scare. He added that it did however have a better safety record than Boeing! The clerk at the check-in desk issued us with a weather warning! She explained that should plane take off and not be able to land at our destination because of the bad weather then the company, Big Sky, would not be liable. Brave travellers the lot of us we accepted this condition, thinking that it might be exciting. We admired through the window the lightning storm thrashing around outside the terminal building. I asked the check-in clerk for a window seat to get a good view. “They all have windows sir,“ he replied. A slight recess in the storm prompted ground control to give the flight the go ahead. At the departure desk there were eight Earthwatchers in the same boat - an inappropriate term - but we managed to somehow recognise each other - informal dress, backpacks, sleeping bags, sun hats and overheard conversations. Most of us were teachers. Two taught Geography in England, three taught Science, one in Wales, one in England and the other in America. There was also a retired businesswoman, a chemical engineer and an almost retired salesman.

Nothing like recovered from seven hours of jet lag I was excited at the prospect of a fortnight with a large number of similar volunteers in the badlands of northeastern Montana on an expedition investigating the extinction of the dinosaurs. It led to a degree of light-headedness. Who cares if the plane didn't reach Glasgow? We'd survive. The eternal optimist. Nervous reaction probably.

It was very blustery as we crossed the tarmac to board the sixteen-seater twin-propped airplane. We had to bend over to squeeze into our seats and, in the lull of the storm, took off. The pilot veered westwards around the edge of the storm but the turbulence still threw us about. Being lifted several inches off one's seat and banging one's head on the ceiling of the aeroplane was certainly unexpected. There were two sick bags per seat but they weren't needed luckily. We'd planned to eat steak when we got there. The other local passengers recognised we were well off course avoiding the eye of the storm over Glasgow. We were forced to land at Le Havre - 180 miles to the west. The pilot told us that hurricane force winds and tremendous rains meant it was impossible to land at Glasgow. He rang head office and then told us that the airline had no responsibility for what we chose to do and then disappeared into the night! At least he landed us safely!

What to do? The eight of us Earthwatchers, a young soldier on his way home to see his parents, a frail old lady who was convinced God had called for us, and a marvellously capable mother with a seven month old baby. She really helped the old lady to get overnight accommodation and an onward flight the next morning to Glasgow. Between us though, our combined initiative solved our problem. We shared three hired cars and, after some fast food at the ubiquitous McDonalds, we drove over three hours through the night back to Glasgow. My role was to keep the driver awake. I plied her with questions about house prices, land values, farming, rural and urban problems in Montana and Seattle where she was from, families, holidays etc. Interesting and educational but exhausting having to keep awake with my jet lag. She told me that all the stations along the railroad we were following were named by spinning a globe round, stopping it with a finger and using the nearest name. We drove slowly, rarely over 50 mph. The dangers of hitting elk, antelope or deer at night and at speed made us very conscious of driving safely. (We were told subsequently that an antelope did £1,000 worth of damage to one of the Earthwatch trucks.) Eventually we checked in to our Glasgow motel six hours late. We jokingly called ourselves the CIA - Comrades in Adversity.

Thus began our two weeks Earthwatch expedition under Professor Keith Rigby. He preferred being called “Doc“. In fact, when we met up with the rest of the Earthwatch team - another eleven - outside the Post Office in downtown Glasgow at 4.00pm. the Sunday afternoon, we were in for another surprise. The accommodation we thought we'd be staying in was a four-bedroomed cabin on the banks of Fort Peck Reservoir with an outside chemical toilet and tents for those who felt the night-time temperatures indoors were too hot. As it turned out there were twenty-six of us. “Doc“ had bought a duplex - two semi-detached houses on a disused and hardly occupied residential section of an airbase previously used by the USA's Strategic Bomber Command. It was about seventeen miles north of Glasgow and, instead of a half-mile walk; it was about an hour's drive to the reservoir. The houses had been knocked together to provide eight sleeping rooms (bunk beds and mattresses on the floor), six washrooms, two make-shift showers in the cellars (fall-out shelters), a long dining room, a communal sitting room/lecture theatre and a big kitchen with all mod cons. Lots better than a summer cabin but the view over the reservoir was missing. Instead it was a lot of prairie grass to the east, Boeing's 777 test base and Canada to the north and the open plan houses and gardens of the almost deserted airbase to the south and west.

So how were a gang of twenty-six of us, Doc, his daughter the cook, five of his University students who'd volunteered to help him for part of their summer vacation, as well as nineteen Earthwatchers going to survive this interesting environment? Very well, in fact. The youngest of the team was a seventeen-year old student and the eldest was in his mid-60s. We included teachers, college and university students (under and post-graduates), an engineer, business people, a farmer and horse-breeder, a forester and a chiropractor.

The first evening the house rules were laid down. Wash up your own litre-sized mugs, in bed with lights out and quiet by eleven, up at six in the morning for breakfast, take turns in “kitchen patrol“ which included helping with meals (which were generally superb), putting washing up things in the dishwasher, cleaning floors, washrooms, bedrooms etc. We took to the routine no problem of course. Occasionally someone didn't pull their eight - often for reasonable reasons like a stomach upset, sunstroke or exhaustion - but between us we ran a very good house.

But that wasn't the main objective of our volunteering. We'd all got good reasons for coming on this trip. It was from our varied interests in dinosaurs. I was one of four British teachers who had won a teaching fellowship awarded by 3M. Their stated concern for the environment is manifested by their sponsoring teachers to engage in worthwhile academic environmental research as we are best placed to relate the results to future generations.

This area of heavily eroded badlands in northeastern Montana is rich in dinosaur and other prehistoric remains. Doc has found evidence of a huge drop in sea level associated with tectonic upthrust, which occasioned massive vertical erosion by what is now called the Missouri River. Much rock strata has been exposed and fossils of at least 30 species of dinosaurs have been found in the sandstones and mudstones of Bug Creek and surrounding terrain. Excavations started here almost 100 years ago with finds being sent to museums across the country. They include remains of Tyrannosaurus Rex and Triceratops.

Doc Rigby is an eminent palaeontologist from the University of Notre Dame, Indiana. He's been working in this locality for many seasons and has, with the aid of fellow scientists from around the world and numerous teams of Earthwatch volunteers and his students to do the donkey-work, produced some fascinating new ideas about dinosaur extinction. They will mean some significant revision of the data in the world's dinosaur museums and textbooks. He calls his theory the Pele Hypothesis.

Based on information he and Earthwatch teams have gathered in this area, geological maps and related literature, local knowledge of ranchers with property on these badlands and extensive field walking, he has located massive fossil bone beds rich in dinosaur and other remains covering the period of peak dinosaurs about 130 million years ago through a period of gradual decline up to about 63 million years ago. He is now challenging the commonly accepted theory about dinosaurs being made extinct by the impact of an asteroid that smashed into the Yucatan peninsula in the Gulf of Mexico 65 million years ago. The clouds of dust and gases emitted by this impact were supposed to have created a greenhouse effect, which led to increased temperatures, vegetation changing and dinosaurs and other species to be wiped out. This period is known as the K-T boundary - the junction between the Cretaceous and the Tertiary geological periods and is known as one of many mass extinctions. However, Earthwatch teams in Montana have uncovered and identified five of the thirteen species of American dinosaurs in the strata before the K-T boundary and thirteen species and other animals that survived this impact by about two million years. These were found in Tertiary river channels and evidence shows that they were not washed out from the earlier deposits.

Teams, including mine, were on the road, often just after seven in the morning, and driven to the field in air-conditioned 12-seater van and six-seater pick-up truck armed with wheelbarrows, crow-bars, shovels, pick-axes and sacks. The large bones that were exposed on the surface or that we encountered in our digging - especially the articulated ones - were meticulously removed. My spade twanged on a six-inch wide vertebra of what was thought to be a Triceratops, which sparked off great excitement. It also gave the team a deserved rest period in the 40°C heat while the “experts“ got to work examining it. My team was working on “Big Bugger“, a Tertiary river channel from which we shovelled about 200 tons! Some worked with pick-axes or crow-bars to release the hard deposits; the diggers shovelled the dirt into burlap sacks - about thirteen shovelsful per sack. Others worked as “mules“, holding the sacks open and then hauling or carrying them over to a wheelbarrow into which three or four were dumped. Depending on the digger, some weighed in at 40 pounds but they averaged about 60. One over-enthusiastic volunteer contributed 130 pounds to one sack - not appreciated by the mule. The barrow was wheeled over the rough terrain to the pick-up truck which, despite four-wheeled drive, was unable to get right up the eroded valley side to where our operations were centred. The stronger volunteers manhandled the sacks of dirt onto the back of the truck where they were weighed and stacked. Careful records were kept of numbers and weights. We all played important roles.

Wandering around the site taking our regular water breaks I wondered at the formation of this badlands topography, soaked in the intense heat, kept my eyes open for bones, spotted the occasional antelope staring at the odd antics of our team intruding into its habitat, scared off rattlesnake, killed a scorpion once, took swigs of juice from my essential litre-bottle of water, chatted to fellow heat and labour exhausted colleagues, shot some video footage for Earthwatch, took a picture or three and then got back to work. Just one body not pulling their weight would soon be noticed. There was never really cause for discontent amongst the workers. We became a friendly, if dirty, cosmopolitan bunch. Lunch of sandwiches and fruit was always consumed in whatever shade we managed to find. There were no woodpeckers in Montana we were told. There were so few trees that we often lay under the van or truck!

The drive down the banks of Fort Peck Reservoir in air-conditioned transport was greatly appreciated. Shared hard work formed good relationships between us. We had very entertaining chat in the van. Every now and then it was educational! Doc invariably drove the pick-up truck so more academic discussions took place in there. Once off-loaded from the truck the bags of dirt were emptied into about eighty 2' x 2' wooden boxes with 2mm. mesh screens nailed onto their base. We formed a human chain or two to transport the half-full boxes to the water's edge where we carefully lined them up, semi- or totally immersed waiting for the next stage. Getting into the cold water was a pleasure on a hot and humid afternoon. Flicking grasshoppers off one or slapping the blood-sucking mosquitoes on one's legs, arms and body became second nature. In good American fashion we even took to slapping each other.

After a day's good soak the dirt boxes were then dragged into the reservoir and waist-deep in the water, or knee-deep in the mud if you wanted to be closer to shore and get an aching back, we washed away as much sand and clay as we could to reveal a small volume of stones and what we lovingly called “treasure“. The washed boxes were then handed out crocodile-style to people on the shore who laid them out on the grassy bank to spend a day drying out in the sun. Often they needed a second wash on our following visit. Once it was dried, the material was emptied into a barrow sacked, lifted into the truck and weighed again. Careful note was made of the source of the material so as not to mistake it with deposits from other sites. Doc's aim was to identify the number and species of creatures from different strata that were deposited before, during and after the K-T boundary.

Once back at base, depending upon its condition, the “treasure“ was given a third wash in large wooden screens set up in a row in the back yard. Power hoses then removed any unwanted clay or sand. Spread out on a tarp (aulin) it quickly dried in the summer heat. Pity help any subsequent tenants with the amount of silt that ran onto the garden and the waste stones that were emptied into the grass. The final product was sacked and ready for the next stage. We took it in turns to sit by a wheelbarrow, scoop out a couple of cupfuls into a 2mm. sieve, shake the smaller material into the barrow, sack the bigger stuff and carefully label it. The barrowload of less than 2mm. material was emptied into yet another sack for microscopic examination back in Doc's lab at University. There is a machine being developed called the “Magstream“ which it is hoped will separate bone from rock by centrifugal force.

The most difficult job of the entire trip was the careful scrutinising of the “treasure“ over 2 mm. Each particle had to be turned over with tweezers, penknife or delicate fingers and examined to see if it had the tell-tale feature of a tiny bone, a vertebra, a tooth, a claw or a “poop.“ A poop was the students' term for a coprolite - a fossilised dropping! Careful examination of these leads to clues about the creatures' diets. We spent hour after hour engaged in intense observation, often under electric light, from eight in the morning until it was warm enough to sit at picnic tables outside. When it got too hot we retired indoors again. Why such labour intensive work? For my group it was essential to Doc's research that we helped him identify the species that had survived the K-T boundary event; those that were not water-worn, reworked fossils that his critics might argue had been washed out of the surrounding Cretaceous beds.

After we had sorted what we believed were bones etc. the staff went through our piles and carefully checked both the residue and the good stuff. We gradually became experts. Like good teachers they never reprimanded us for our mistakes, rather praised us for the successful finds and explained our errors. Very encouraging and soon we were able to recognise the tell-tale signs of prehistoric bones. Mind you, on going to sleep at night, most of us found it amusing that on closing one's eyes all one could see was an assortment of fossilised marrow, bones and teeth floating by in profusion.

Not that I can put it on my CV but I am now a master at identifying small fossils. The staff team helped us to identify the scales of garfish, bones, jaws and teeth of alligators, crocodiles and small mammals, the carapace of turtles and, most interestingly, the bones, teeth and jaw of five taxa of dinosaurs - hadrosaurs, ceratopsians, ankylosaurs, pachycephalosaurs and therapods.

Just digging up fossils wasn't the only contribution we made to Doc's research. I was part of a team that was sent off one morning to collect amber samples from one of the many thin coal seams that were exposed in the badlands topography. The most recent coal seam was the Z-coal. We were told that nothing had been found in the Y-coal in a locality near Wolf Point called “Nmnm“ so we were to treat this as useful practice in searching. After several hours of fruitless scrabbling in temperatures over 40°C on the steep slopes of arroyos - washed out river beds - and poking out tiny particles of brittle coal on our way back to the truck I ventured up an almost vertical slope where it turned a corner at what I later called “O'Connor's Bluff“. I was lucky. My penknife exposed some tiny orange crystals in the coal. “I've found some,“ I shouted and was quickly in the shadow of one of Doc's students. He was ecstatic. Carefully I scraped it into a plastic film container and clambered down to show everyone. Back at the pick-up when it was emptied into Doc's palm he dropped it! Scouring the grass for every tiny particle took time but I was told that I had increased the world's known collection of amber from the Y-coal by a factor of ten!

He explained that the amber samples were sent off to a laboratory in Denmark for careful analysis. Placed in a vacuum they were crushed and the bubbles of air that had been trapped in the resin all those millions of years ago were released. Using a mass spectrometer it was then possible to determine the % of Oxygen in the air at the time it was formed. This palaeoclimatic analysis of amber from about twenty coal seams covering the period 130 to about 60 million years ago shows that Oxygen levels in the air decreased from about 30% when dinosaur numbers were at their peak to around 11% 65 million years ago. Now it's about 21%. The fossil evidence that Doc's students and Earthwatch teams have uncovered from the same geological section shows that there was a dramatic decline in the numbers and species of dinosaurs from thirty 130 million years ago to thirteen at the K-T boundary and thirteen after it. This decline almost perfectly mirrored the fall in Oxygen levels in the air.

Analysis of pollen made from samples collected by other volunteers is also helping to fill in the details of a complicated picture. Nearly all fossil pollen has survived. Microscopic examination shows that some species did become extinct, others were “created“ after wards. The fern Spore Spike was a dominant species at the Event. Ferns were the first to recolonise Mount St Helens after its recent eruption.

Whilst I was searching for amber at another site I disposed of a scorpion that might have necessitated an inconvenient hospital visit. It was hiding in a crack in a thin coal seam I was picking at with my penknife. I thought of taking it home but wasn't sure whether rigor mortis might set in in my pocket.

Other team members helped collect samples of volcanic ash from another site near Wolf Point. At the “Ditch“ we were shown a grey white ash bed, which we measured at 60 feet thick. Doc explained that compaction rates of three to one meant that when the ash was first deposited it would have been 180 feet thick! There was obviously a very large eruption close by that was many, many times more devastating than Mount St Helens. Samples of this ash were taken at every foot across the exposure, which were carefully bagged, labelled and then sent for palaeomagnetic analysis at his lab. Hopefully they would also show evidence of shocked quartz and a second iridium layer. Shocked quartz and iridium at the K-T boundary have been used as evidence of an asteroid impact. In one of Doc's evening lectures he suggested that the iridium layer, recognised world-wide at the K-T boundary and supposed to be of extra terrestrial origin, could in fact have originated from volcanic eruptions occurring at the same time as dinosaur numbers were falling. The volcanic ash thrust miles high into the atmosphere would have spread around the world, blackened the sky and contributed to an earlier greenhouse effect. Clouds of poisonous volcanic gases could easily account for the large numbers of dinosaur graveyards.

The Montana volcano wasn't the only eruption. There was enormous flood basalt activity in India at the same time. Vast quantities of runny lava spread out and cooled to produce

the Deccan Plateau. Across the Indian Ocean near Indonesia an enormous seamount - an underwater uplift of rock strata - known as Anton Java - has also been documented as occurring at this time. Emissions of Carbon Dioxide into the atmosphere not only reduced Oxygen levels but also had a significant impact on all respiratory systems. Just a 1% increase can kill off people. Herds of cattle have died when clouds of gas sank down the slopes of one of Africa's rent volcanoes. The biggest dinosaurs just couldn't cope. Increased temperatures associated with the greenhouse effect would have affected the dinosaurs as well as having a dramatic impact on their major food source - vegetation.

Doc jokingly called one of his lectures “Dinosaur Breath“. Huge dinosaurs with high metabolic rates and inefficient metabolisms could not survive. Analysis of dinosaur footprints shows that their speed slowed down from 5mph to 2.5mph. He suggests that some may not have been able to get back to the herds' mating or nesting ground by the sandy lake shore or seaside. Over time this would have reduced numbers. It was also suggested that some were probably too exhausted to have sex. One wonders about its effect on dinosaur's sperm count.

In another of Doc's lectures he told us about his work in Nan Xiong in southern Guangdong province in South China, an area with similar geological strata to Montana. Chinese geologists had shown him and a group of his students their dinosaur beds and what would have been a huge dinosaur nursery. The area was rich in dinosaur eggs and dinosaur footprints. In one cubic metre there were about 1,000 eggs! The fact that there were so many unhatched eggs was a puzzle. Were they flooded? Doc's analysis suggested another reason. Their shells were leathery, like reptile eggs. Being porous they would have absorbed the carbon dioxide and other poisonous gases from the volcanic eruptions. Careful examination showed that the embryos were deformed or never developed. It is known that alligator and crocodile eggs are sensitive to temperature changes during gestation. Higher temperatures produce an all-female batch and colder temperatures all-male. They therefore bury them at different depths. It is unknown whether dinosaurs did so. With such relatively small brains it is suggested that they didn't. In which case a predominantly single sex batch of offspring would have had a significant impact on reducing their numbers.

My discovery of a triceratops vertebra at a site post-dating the asteroid impact is just a small addition to a body of evidence showing that a number of dinosaurs survived the impact. There wasn't an immediate world-wide mass extinction. Many species were wiped out at that time but evidence shows that extinction was faunally selective. A number of species appeared after the event. The carapace, scales, bones, teeth and jawbones that we meticulously removed from Big Bugger showed that it was only the smaller dinosaurs and mammals that survived. Species of grazing animals and carnivores survived; those with a low metabolic rate and a more efficient respiratory system did. Carbonate organisms suffered much more than siliceous. In 1m³ of water 10,000 species of carbonaceous organisms dropped to only four. Siliceous species remained virtually untouched. Why? Both photosynthesised but the carbonaceous species have the highest metabolic needs of Oxygen and it was a reduced Oxygen level that was affecting the dinosaurs.

One recent team of Earthwatch volunteers made a valuable contribution to Doc's research. They stumbled across the articulated skeleton of a triceratops. They called it appropriately, Katie. Examination of its skull showed a large opening not found in modern rhino. Its horns were 60% hollow and only 3/4 inch thick. A modern rhino horn is 2.5 inches thick. Triceratops' frill was only 1/2 inch thick. Its outer casing had a huge network of arteries all cross-linked, straight and circular in cross-section. Its under shell was covered in neural canals. These don't suggest an offensive animal. Frill indentations some scientists have interpreted as percussion wounds. Doc argues that they were cists. Doc is suggesting that dinosaurs had to evolve thermo-regulatory functions. A sophisticated body cooling mechanism helped triceratops and other dinosaurs to survive the increased temperatures. Museums and dinosaur experts around the world are going to have to revise their ideas in the light of this research. And it was with the help of Earthwatch funding and scores of Earthwatch volunteers, myself included, that have helped him put forward his Pele Hypothesis.

Pele was a Hawaiian fire-goddess - a she-witch, a wicked, pervasive, vindictive character, unlike Gaia - the Earth goddess. Volcanic eruptions and flood basalt lavas were largely responsible for the eventual demise of the dinosaurs. They showed no mercy. Pele had Gaia by the throat. These igneous events set the gears in motion. They led to increased carbon dioxide output. The volcanic dust in the atmosphere resulted in a greenhouse effect. Temperatures rose. Vegetation levels dropped. There were also decreases in sea levels. Land rose as a result of tectonic influences. This led to lower water tables and dramatic increases in river erosion. It exposed ancient coal seams which oxidised to further reduce atmospheric oxygen. The carbon in the exposed coal also increased CO2 levels and stripped out the oxygen from the atmosphere. The tectonic uplift also caused changes in ocean circulation which resulted in changed weather patterns. There were plant and animal extinctions. There were changes in atmospheric gases. Oxygen levels dropped which led to lower speed of dinosaurs. They had to “dash and dine“ like present day crocodiles. This may well have led to reduced numbers reaching their mating grounds. The bigger ones were too tired for sex! The poisonous gases influenced embryo development. The increased temperatures may have led to a single-sex offspring. They had no chance.

Doc's technique was rather like a “Murder Fortnight“. Who killed the dinosaurs? One was given snippets of information at the beginning of the fortnight and taken out in the field to see for oneself or to collect material to examine. It made one want to question and find the evidence oneself. In time, more bits of the theory were revealed and depending upon whether one sat in the truck and quizzed him, some got there earlier than others. There were lots of quizzes. One excursion involved having to locate and identify as many fossil-bearing strata as one could in Bug Creek. By the end of the session one had traversed the immediate area but it was all revealed. Fascinating to be at the front end of academic research.

My Earthwatch trip was only a small link in the chain, a small but vital cog in the machine, an injection of enthusiasm and effort into the system. Being at the knife-edge of a new theory of global importance was very exciting. Volunteers, like myself, have helped provide the evidence of a complicated and multi-faceted hypothesis about dinosaur extinction. Doc's ideas will also help pull together many of the loose ends floating around at the K-T boundary. Back at school I have been inundated with enquiries from both staff and pupils. This report will satisfy most of the enquiring minds but I've also got a fascinating lecture or three out of this trip.