Showing posts with label FIELD. Show all posts
Showing posts with label FIELD. Show all posts

Wednesday, April 24, 2024

CHUCKANUT DRIVE: EOCENE TROPICAL PARADISE

A trip along Chuckanut Drive, in northwestern Washington is a chance to view incredible diversity from sea to sky.

An amazing array of plants and animals call this coastline home. 

For the fossil enthusiast, it is a chance to slip back in time and have a bird’s eye view of a tropical paradise preserved in the Eocene strata of various fossil sites. 

Snug up against the Pacific Ocean, this 6000m thick exposure yields a vast number of tropical and flowering plants that you might see in Mexico today. Easily accessible by car, this rich natural playground makes for an enjoyable daytrip just one hour south of the US Border.

Over vast expanses of time, powerful tectonic forces have massaged the western edge of the continent, smashing together a seemingly endless number of islands to produce what we now know as North America and the Pacific Northwest. Intuition tells us that the earth’s crust is a permanent, fixed outer shell – terra firma.

Aside from the rare event of an earthquake or the eruption of Mount St. Helen’s, our world seems unchanging, the landscape constant. In fact, it has been on the move for billions of years and continues to shift each day. As the earth’s core began cooling, some 4.5 billion years ago, plates, small bits of continental crust, have become larger and smaller as they are swept up in or swept under their neighboring plates. 

Large chunks of the ocean floor have been uplifted, shifted and now find themselves thousands of miles in the air, part of mountain chains far from the ocean today or carved by glacial ice into valleys and basins.

Two hundred million years ago, Washington was two large islands, bits of continent on the move westward, eventually bumping up against the North American continent and calling it home. Even with their new fixed address, the shifting continues; the more extreme movement has subsided laterally and continues vertically. 

The upthrusting of plates continues to move our mountain ranges skyward – the path of least resistance. This dynamic movement has created the landscape we see today and helped form the fossil record that tells much of Washington’s relatively recent history – the past 50 million years.

Chuckanut Drive is much younger than other parts of Washington. The fossils found there lived and died some 40-55 million years ago, very close to where they are now, but in a much warmer, swampy setting. The exposures of the Chuckanut Formation were once part of a vast river delta; imagine, if you will, the bayou country of the Lower Mississippi. The siltstones, sandstones, mudstones and conglomerates of the Chuckanut Formation were laid down about 40-54 million years ago during the Eocene epoch, a time of luxuriant plant growth in the subtropical flood plain that covered much of the Pacific Northwest.

This ancient wetland provided ideal conditions to preserve the many trees, shrubs & plants that thrived here. Plants are important in the fossil record because they are more abundant and can give us a lot of information about climate, temperature, the water cycle and humidity of the region. 

The Chuckanut flora is made up predominantly of plants whose modern relatives live in tropical areas such as Mexico and Central America. If you are interesting in viewing a tropical paradise in your own backyard, look no further than the Chuckanut. 

Images and tag lines: Glyptostrobus, the Chinese swamp cypress, is perhaps the most common plant found here. Also abundant are fossilized remains of the North American bald cypress, Taxodium; Metasequoia (dawn redwood), Lygodium (climbing fern), large Sabal (palm) and leaves from a variety of broad leaf angiosperm plants such as (witch hazel), Laurus (laurel), Ficus (fig) and Platanus (sycamore), and several other forms.

While less abundant, evidence of the animals that called this ancient swamp home are also found here. Rare bird, reptile, and mammal tracks have been immortalized in the outcrops of the Chuckanut Formation. Tracks of a type of archaic mammal of the Orders Pantodonta or Dinocerata (blunt foot herbivores), footprints from a small shorebird, and tracks from an early equid or webbed bird track give evidence to the vertebrates that inhabited the swamps, lakes and river ways of the Pacific Northwest 50 million years ago.

The movement of these celebrity vertebrates was captured in the soft mud on the banks of a river, one of the only depositional environments favorable for track preservation.

Friday, February 16, 2024

UPTHRUSTING PLATES: WASHINGTON GEOLOGY

Two hundred million years ago, Washington was two large islands, bits of the continent on the move westward, eventually bumping up against the North American continent and calling it home. The shifting continues, subtly changing the landscape like a breath. We only notice when pockets of resistance manifest as earthquakes, some newsworthy, some all but unnoticed. For now, the more extreme movement has subsided laterally and continues vertically, pushing California towards the North Pole. Hello Baja-BC.

The upthrusting of plates move our mountain ranges skyward – the path of least resistance. And it is this dynamic movement that's created the landscape we see today.

The 3,000 meters of the stratigraphic section of the Chuckanut Formation along Chuckanut Drive span an age range of just a few million years. The lower part is late Paleocene with a radiometric age of around 56 million years. The upper part of the section is early Eocene. The fossils found here lived and died very close to where they are now but in a much warmer, wetter, swampy setting. The exposures of the Chuckanut Formation were once part of a vast river delta; imagine, if you will, the bayou country of the Lower Mississippi. The siltstones, sandstones, mudstones and conglomerates of this formation were laid down during a time of luxuriant plant growth in the subtropical flood plain that covered much of the Pacific Northwest.

This ancient wetland provided ideal conditions to preserve the many trees, shrubs and plants that thrived here giving us a lot of information about climate, temperature, the water cycle and humidity of the region. The Chuckanut flora is made up predominantly of plants whose modern relatives live in tropical areas such as Mexico and Central America. While less abundant, evidence of the animals that called this ancient swamp home are also found here. Rare bird, reptile, and mammal tracks have been immortalized in the outcrops of the Chuckanut Formation.

Sumas Eocene Shorebird Trackway
Tracks of a type of archaic mammal of the Orders Pantodonta or Dinocerata (blunt foot herbivores), footprints from a small shorebird, and tracks from an early equid or webbed bird track give evidence to the vertebrates that inhabited the swamps, lakes and riverways of the Pacific Northwest 50 million years ago.

Fossil mammals and bird trackways from Washington State have caused great excitement over the past few years. Many new trackways have been discovered since the 2009 slides near Sumas. George Mustoe and team collected these important finds, bringing them to the Burke Museum in Washington State to study and make available for display.

The movement of these vertebrates was captured in the soft mud on the banks of an ancient river, one of the only depositional environments favourable for track preservation. The terrestrial paleontological record of Washington State at sites like Chuckanut and Racehorse Creek (U-Pb 53 Ma.) is primarily made up of plant material with some wonderfully enticing mammal, shorebird (seen here) and large Diatryma bird tracks on rare occasions.

Thursday, December 1, 2022

BC'S FOSSIL BOUNTY: BEHIND THE SCENES WITH JOHN FAM

Meet John Fam, Vice Chair of the Vancouver Paleontological Society. 

The awesome folk in the Vancouver Paleontological Society and Vancouver Island Palaeontological Society have been collecting with John for many years, some exciting local trips — and some epic trips of a lifetime. 

Visiting the fossil outcrops at Tyaughton in the Taseko Lakes area of British Columbia takes months of planning. Remote, dangerous and difficult to reach, these sites are epic and each of those field trips definitely count as trips of a lifetime.

John shares Tales of Tyaughton in his episode of BC's Fossil Bounty.

"For the longest time, a handful of BCPA members have known about the wonderful Triassic-Jurassic fossils of the Tyaughton Creek area. Some of us had been even fortunate to see the spectacular collection of Jurassic ammonites stored in the basement of the Geological Survey of Canada.

I still remember purchasing a copy of Hettangian Ammonoid Faunas of the Taseko Lakes Area by Hans Frebold and wondering if I would even get a chance to visit such a remote locality. If you picture a squid living inside a sea shell floating and hunting in the ocean, these were the ancient creatures we’d be looking for.

As Karen Lund, one of the Directors of the Vancouver Paleontological Society (VanPS), told me, "Tyaughton is kind of like the Eldorado for the VanPS.”

We had heard so many stories that this site was becoming somewhat legendary in our minds. Thus, I made it a personal goal of mine to visit the remote fossil beds.

I began researching all possible sources related to Tyaughton Creek. I dug up many old GSC reports by Hans Frebold, Howard Tipper and George Jeletzky along with more recent material by Paul-Smith and his grad students.

All this literature was very helpful in understanding not only the fossil localities but also the complex geology of the region. I also paid a couple of visits to Dr. Howard Tipper of Geological Survey of Canada. 

Dr. Tipper was very supportive and helpful in providing valuable information regarding the fossil sites. He also shared with me his extensive knowledge of Jurassic palaeontology.

Armed with this information, I met up with Heidi Henderson, then Chair of the Vancouver Palaeontological Society, who you’ll know as the Fossil Huntress, to plan the first of four expeditions.

We had to figure out how to access such a rugged and remote locality. The fossil beds are 16 km from the nearest logging road, several hundred kilometres from Vancouver and 7,500 feet above sea level.

We would be sharing territory with a healthy Grizzly bear population and likely be a food source for the not as large but equally daunting horsefly population. 

We were keen to access this elusive site, but hiking in 16 km and gaining about a thousand feet or more of elevation would be a challenge. Hiking back out with 50 kg of rock would be impossible. 

We finally decided that it would be best that we fly in by helicopter. That, too, provided its own challenges. In the end, we did four trips over many field seasons. 

We met many Grizzly bears, horseflies, we were snowed in but came away with many wonderful fossils including new species. The undergrad we brought on the first trip did her PhD over that time and now teaches at the University of British Columbia."

Here's John Fam Behind the Scene prepping for that episode and Eva Svobodova doing her magic with Hair and Makeup on the set at Shoreline Studios in Vancouver. 


Friday, June 10, 2022

HARRISON LAKE FOSSILS

Located three hours east of Vancouver, most folks head to Harrison Lake to enjoy its crisp waters, soak in the hot springs, camp or four-wheel-drive immersed in rugged scenery, or look for the elusive Sasquatch reported to live in the area. 

But there are some who come to Harrison Lake and miss the town entirely. Instead, they favour the upper west side of the lake and the fossiliferous bounty found here.

Indeed, this is the perfect location for local citizen scientists to strut their stuff. Harrison is a perfect family day trip, where you can discover wonderful marine fossil specimens as complete or partially crushed fossilized shells embedded in rock. 

It is truly amazing that we can find them at all. These beauties range in age from Jurassic to Cretaceous, with most being Lower Callovian, meaning the ammonites here swam our ancient oceans more than 160 million years ago. 

The area around Harrison Lake has been home to the Sts’ailes, a sovereign Coast Salish First Nation for thousands of years. Sts’ailes’ means, “the beating heart,” and it sums up this glorious wilderness perfectly. They describe their ancient home as Xa’xa Temexw or Sacred Earth. 

With the settling of Canada, Geologists began exploring the area in the 1880s, calling upon the Sts’ailes to help them look for coal and a route for the Canadian Pacific Railway. Coal was the aim, but happily, they also found fossils. Sacred Earth, indeed.  

Belemnite Fossils
In my favourite outcrops, you can find large, smooth inflated Jurassic ammonites along with their small grey and brown cousins. 

Further up the road, you will see Cretaceous cigar-shaped squid-like cephalopods called Belemnites, and the bivalve (clam) Buchia — gifts deposited by glaciers. Here are the most common.

Ammonites

Almost all of the ammonite specimens found near Harrison Lake are the toonie sized Cadoceras (Paracadoceras) tonniense with well-preserved outer whorls but flattened inner whorls. We find semi-squished elliptical specimens here, too. If you see a large, smooth, inflated grapefruit-sized ammonite, you are holding a rare prize — a Cadoceras comma ammonite, the macroconch or female of the species.  

Ammonites were predatory, squid-like creatures that lived inside coil-shaped shells. Like other cephalopods, ammonites had sharp, beak-like jaws inside a ring of squid-like tentacles that extended from their shells. They used these tentacles to snare prey — plankton, vegetation, fish and crustaceans — similar to the way a squid or octopus hunts today.

Within their shells, ammonites had a number of chambers called septa filled with gas or fluid, and they were interconnected through a wee air tube. By pushing air in or out, they were able to control their buoyancy. 

These small but mighty marine predators lived in the last chamber of their shell and continuously built new shell material as they grew. As they added each new chamber, they would move their squid-like body down to occupy the final outside chamber.

Interestingly, ammonites from Harrison Lake are quite similar to the ones found within the lower part of the Chinitna Formation near Cook Inlet, Alaska, and Jurassic Point, Kyuquot, on the west coast of Vancouver Island — some of the most beautiful places on Earth. 

Buchia (bivalve) Clams

The bivalve or clam Buchia are commonly found at Harrison Lake. You will see them cemented together en masse. . They populated Upper Jurassic–Lower Cretaceous waters like a team sport. When they thrived, they really thrived, building up large coquinas of material. Large boulders of Buchia cemented together en masse hitched a ride with the glaciers and were deposited around Harrison Lake. Some kept going and we find similar erratics or glacier-deposited boulders as far south as Washington state. 

Buchia is used as Index Fossils. Index fossils help us to figure out the age of the rock we are looking at because they are abundant, populate an area en masse, and then die out quickly. In other words, they make it easy to identify a geologic time span.

So what does this mean to you? Now, when you are out and about with friends and discover rocks with Buchia, or made entirely of Buchia, you can say, “Oh, this looks to be Upper Jurassic or Lower Cretaceous. Come take a look! We're likely the first to lay eyes on this little clam since dinosaurs roamed the Earth.” 

You will impress the pants off them — very high-five worthy.

Fossil Collecting at Harrison Lake Fossil Field Trip — Getting there

This Harrison Lake site is a great day trip from Vancouver or the Fraser Valley. You will need a vehicle with good tires for travel on gravel roads. Search out the route ahead of time and share your trip plan with someone you trust. If you can pre-load the Google Earth map of the area, you will thank yourself. 

Heading east on from Vancouver, it will take you 1.5-2 hours to reach Harrison Mills. 

Access Forestry Road #17 at the northeast end of the parking lot from the Sasquatch Inn at 46001 Lougheed Hwy, Harrison Mills. From there, it will take about an hour to get to the site. Look for signs for the Chehalis River Fish Hatchery to get you started. 

Drive 30 km up Forestry Road #1, and stop just past Hale Creek at 49.5° N, 121.9° W (paleo-coordinates 42.5° N, 63.4° W) on the west side of Harrison Lake. You will see Long Island to your right. 

The first of the yummy fossil exposures are just north of Hale Creek on the west side of the road. Keep in mind that this is an active logging road, so watch your kids and pets carefully. Everyone should be wearing something bright so they can be easily spotted.

How to Spot the Fossils

The fossils here are easily collected—look in the bedrock and in the loose material that gathers in the ditches. Specimens will show up as either dark grey, grey-brown or black. Look for the large, dark-grey boulders the size of smart cars packed with Buchia. 

And while you are at it, be on the lookout for anything that looks like bone. This site is also ripe for marine reptiles—think plesiosaur, mosasaur and elasmosaur. As a citizen scientist and budding palaeontologist, you might just find something new!

What to Know Before You Go

Fill your gas tank and pack a tasty lunch. As with all trips into British Columbia's wild places, dress for the weather. You will need hiking boots, rain gear, gloves, eye protection, and a good geologic hammer and rock (cold) chisel. 

Wear bright clothing and keep your head covered. Slides are common, and you may start a few if you hike the cliffs. If you are with a group, those collecting below may want to consider hardhats in case of rockfall — chunks of rock the size of your fist up to the size of a grapefruit. They pack a punch. 

Bring a colourful towel or something to put your keepers on. Once you set rock down, it can be hard to find again given the terrain. I take the extra precaution of spraying the ends of my hammers and chisels with yellow fluorescent paint, as I have lost too many in the field. You will also want to bring a camera for the blocks of Buchia that are too big to carry home. 

Identifying Your Treasures

When you have finished for the day, compare your treasures to see which ones you would like to keep. In British Columbia, you are a steward of the fossil, which means they belong to the province, but you can keep them safe. You are not allowed to sell or ship them outside British Columbia without a permit. 

Once you get home, wash and identify your finds. Harrison Lake does not have a large variety of fossil fauna, so this should not be difficult. If your find is coiled and round, it is an ammonite. If it is long and straight, it is a belemnite. And if it looks like a wee fat baby oyster, it is Buchia. This is not always true, but mostly true.

What about collecting fossils in all seasons?. Everyone has a preference. I prefer not to collect in the snow, but I have done it. While sunny days are lovely, it can also be easier to see the specimens when the rock is wet. So, do we do this in the rain? Heck, yeah! 

In torrential rain? 

Yes — once you are hooked, but for your casual friends or the kiddos, the answer is likely no. Choose your battles. They may come with you, but a cold day getting soaked is no fun. 

In time, you will find your inner fossil geek — probably with your first find. And that's just the tip of the iceberg. First, it will be you, then your kids, your friends and then your neighbour. Once you start, it is easy to get hooked. Fossil addiction is real, and the only cure is to get out there and do it some more. You've got this!

References and further information:

A. J. Arthur, P. L. Smith, J. W. H. Monger and H. W. Tipper. 1993. Mesozoic stratigraphy and Jurassic palaeontology west of Harrison Lake, southwestern British Columbia. Geological Survey of Canada Bulletin 441:1-62

R. W. Imlay. 1953. Callovian (Jurassic) ammonites from the United States and Alaska Part 2. The Alaska Peninsula and Cook Inlet regions. United States Geological Survey Professional Paper 249-B:41-108

An overview of the tectonic history of the southern Coast Mountains, British Columbia; Monger, J W H; in, Field trips to Harrison Lake and Vancouver Island, British Columbia; Haggart, J W (ed.); Smith, P L (ed.). Canadian Paleontology Conference, Field Trip Guidebook 16, 2011 p. 1-11 (ESS Cont.# 20110248).


Monday, July 5, 2021

PTEROSAURS OF HORNBY ISLAND

If you could travel through time and go back to observe our ancient skies, you would see massive pterosaurs — huge, winged flying reptiles of the extinct order Pterosauria — cruising along with you. They soared our skies during most of the Mesozoic — from the late Triassic to the end of the Cretaceous (228 to 66 million years ago). 

By the end of the Cretaceous, they had grown to giants and one of their brethren, Quetzalcoatlus, a member of the family Azhdarchidae, boasts being the largest known flying animal that ever lived. They were the earliest vertebrates known to have evolved powered flight. Their wings were formed by a membrane of skin, muscle, and other tissues stretching from the ankles to a dramatically lengthened fourth finger.

We divide their lineage into two major types: basal pterosaurs and pterodactyloids. Basal pterosaurs (also called 'non-pterodactyloid pterosaurs' or ‘rhamphorhynchoids’) were smaller animals with fully toothed jaws and long tails. Their wide wing membranes connected to their hind legs. This would have allowed them some manoeuvrability on the ground, but with an awkward sprawling posture. They were better climbers with flexible joint anatomy and strong claws. Basal pterosaurs preferred to dine on insects and small vertebrates.

Later pterosaurs (pterodactyloids) evolved many sizes, shapes, and lifestyles. Pterodactlyoids had narrower wings with free hind limbs, highly reduced tails, and long necks with large heads. On the ground, pterodactyloids walked better than their earlier counterparts, manoeuvring all four limbs smoothly with an upright posture. They walked standing plantigrade on the hind feet and folding the wing finger upward to walk on the three-fingered "hand." These later pterosaurs were more nimble. They could take off from the ground, run and wade and swim. Their jaws had horny beaks and some of these later groups lacked the teeth of earlier lineages. Some groups developed elaborate head crests that were likely used to attract mates' sexy-pterosaur style.

So can we or have we found pterosaurs on Hornby Island? The short answer is yes.

Collishaw Point, known locally as Boulder Point, Hornby Island
Hornby Island is a lovely lush, island in British Columbia's northern Gulf Islands. It was formed from sediments of the upper Nanaimo Group which are also widely exposed on adjacent Denman Island and the southern Gulf Islands.

Peter Mustard, a geologist from the Geologic Survey of Canada, did considerable work on the geology of the island. It has a total stratigraphic thickness of 1350 m of upper Nanaimo Group marine sandstone, conglomerate and shale. 

These are partially exposed in the Campanian to the lower Maastrichtian outcrops at Collishaw Point on the northwest side of Hornby Island. Four formations underlie the island from oldest to youngest, and from west to east: the Northumberland, Geoffrey, Spray and Gabriola.

During the upper Cretaceous, between ~90 to 65 Ma, sediments derived from the Coast Belt to the east and the Cascades to the southeast poured seaward to the west and northwest into what was the large ancestral Georgia Basin. This major forearc basin was situated between Vancouver Island and the mainland of British Columbia. The rocks you find here originated far to the south in Baja California and are the right age and type of sediment for a pterosaur find. But are we California dreaming?

Upper Cretaceous Nanaimo Group Fossil Concretion
Well, truth be told, we were with one of the potential pterosaur finds from Hornby. It wasn't just hopeful thinking that had the west coast in a paleo uproar many ago when Sharon Hubbard of the Vancouver Island Palaeontological Society found what looked very much like a pterosaur.

Right time period. Right location. And, we have found them here in the past.

Sandy McLachlan found the first definitive pterosaur, an azhdarchid, back in 2008.

But was Sharon's find a pterosaur?

Victoria Arbour, a Canadian evolutionary biologist and palaeontologist working as a Natural Sciences and Engineering Research Council of Canada postdoctoral fellow at the University of Toronto and Royal Ontario Museum, certainly thought so. 

While Arbour is an expert on ankylosaurs, our lumbering armoured dinosaurs friends, she has studied pterosaurs and participated in the naming of Gwawinapterus from Hornby Island. 

But here's the thing — bony material encased in stone and let to cement for millions of years can be tricky.

While this fossil find was initially described as a very late-surviving member of the pterosaur group Istiodactylidae, further examination cast doubt on the identification. Once more detail was revealed the remains were published as being those of a saurodontid fish, an ambush predator with very sharp serrated teeth and elongate, torpedo-like bodies that grew up to two meters. Not a pterosaur but still a massively exciting find. Arbour was very gracious at the renaming, taking it in stride. She has since gone on to name a partial ornithischian dinosaur from Sustut Basin, as well as the ankylosaurs Zuul, Zaraapelta, Crichtonpelta, and Ziapelta. But she may have another shot at a pterosaur.

Dan Bowen, Chair, VIPS. Photo: Deanna Steptoe Graham
In 2019, Dan Bowen, Chair of the Vancouver Island Palaeontological Society and a truly awesome possum, found some very interesting bones in concretion on Hornby. 

The concretion was nestled amongst the 72 million-year-old grey shales of the Northumberland Formation, Campanian to the lower Maastrichtian, part of the Cretaceous Nanaimo Group from Collishaw Point.

The site is known as Boulder Point to the locals and it has been a popular fossil destination for many years. It is the same site where Sharon made her find years earlier.

The concretion contains four articulated vertebrae that looked to be fish at first glance. Jay Hawley, a local fossil enthusiast was asked to prep the block to reveal more details. Once the matrix was largely removed the vertebrae inside were revealed to be bird bones, not fish and not another saurodontid as originally thought. Palaeontologist Victoria Arbour was called back in to put her keen lens on the discovery. 

You will appreciate that she took a good long look at the specimen and confirmed it to be a bird or a pterosaur. We still do not have confirmation on which it is as yet. The delicate bony material is very flattened with a very shallow u-shape on the bottom but will need additional study to confirm if the skies above California were once home to a great pterosaur who died, was fossilized then rode our tectonic plates to now call Hornby home. It is a great story and one that I am keen to follow.

References: To learn more about the azhdarchid remains found by Sandy McLachlan, check out the paper by Martin-Silverston et al. 2016.