Showing posts with label formation. Show all posts
Showing posts with label formation. Show all posts

Tuesday, March 26, 2024

PARASAUROLOPHUS WALKERI OF ALBERTA

Holotype Specimen of P. walkeri, Royal Ontario Museum
Love Dinosaurs? We can find this beauty— Parasaurolophus walkeri in the Dinosaur Park Formation of Alberta, Canada. 

The Dinosaur Park Formation is the uppermost member of the Belly River Group — also known as the Judith River Group, a major geologic unit in southern Alberta. 

It is an area rich in fossils. The formation contains dense concentrations of dinosaur skeletons, both articulated and disarticulated, often found with preserved remains of soft-tissues. Remains of other animals such as fish, turtles, and crocodilians, as well as plant remains, are also abundant. The formation has been named after Dinosaur Provincial Park, a UNESCO World Heritage Site where the formation is well-exposed in the badlands that flank the Red Deer River.

The Dinosaur Park Formation was deposited during the Campanian stage of the Late Cretaceous, between about 76.9 and 75.8 million years ago in what was an alluvial and coastal plain environment. It is bounded by the nonmarine Oldman Formation below and the marine Bearpaw Formation above.

The formation includes diverse and well-documented fauna including dinosaurs such as the horned Centrosaurus, Chasmosaurus, and Styracosaurus, fellow duckbills Gryposaurus and Corythosaurus, the mighty tyrannosaurid Gorgosaurus, and armoured Edmontonia, Euoplocephalus and Dyoplosaurus

Dinosaur Park Formation is interpreted as a low-relief setting of rivers and floodplains that became more swampy and influenced by marine conditions over time as the Western Interior Seaway transgressed westward. The climate was warmer than present-day Alberta, without frost, but with wetter and drier seasons. Conifers were apparently the dominant canopy plants, with an understory of ferns, tree ferns, and angiosperms.

Some of the less common hadrosaurs in the Dinosaur Park Formation of Dinosaur Provincial Park, such as Parasaurolophus, may represent the remains of individuals who died while migrating through the region. They might also have had a more upland habitat where they may have nested or fed. The presence of Parasaurolophus and Kritosaurus in northern latitude fossil sites may represent faunal exchange between otherwise distinct northern and southern biomes in Late Cretaceous North America. Both taxa are uncommon outside of the southern biome, where, along with Pentaceratops, they are predominant members of the fauna.

Photo: Holotype Specimen: The incomplete Parasaurolophus walkeri type specimen in the Royal Ontario Museum. Location: 43° 40′ 5.09″ N, 79° 23′ 40.59″ W. Shared by MissBossy.

Wednesday, January 3, 2024

UPPER TRIASSIC LUNING FORMATION, NEVADA

Exposures of the Upper Triassic (Early Norian, Kerri zone), Luning formation, West Union Canyon, just outside Berlin-Ichthyosaur State Park, Nevada.

The Berlin-Ichthyosaur State Park in central Nevada is a very important locality for the understanding of the Carnian-Norian boundary (CNB) in North America.

Rich ammonoid faunas from this site within the Luning Formation were studied by Silberling (1959) and provided support for the definition of the Schucherti and Macrolobatus zones of the latest Carnian, which are here overlain by well-preserved faunas of the earliest Norian Kerri Zone. Despite its importance, no further investigations have been done at this site during the last 50 years.

Jim Haggart, Mike Orchard and Paul Smith (all local Vancouverites) collaborated on a project that took them down to Nevada to look at the conodonts (Oh, Mike) and ammonoids (Jim's fav); the group then published a paper, "Towards the definition of the Carnian/Norian Boundary: New data on Ammonoids and Conodonts from central Nevada," which you can find in the proceedings of the 21st Canadian Paleontology Conference; by Haggart, J W (ed.); Smith, P L (ed.); Canadian Paleontology Conference Proceedings no. 9, 2011 p. 9-10.

They conducted a bed-by-bed sampling of ammonoids and conodonts in West Union Canyon during October 2010. The eastern side of the canyon provides the best record of the Macrolobatus Zone, which is represented by several beds yielding ammonoids of the Tropites group, together with Anatropites div. sp. Conodont faunas from both these and higher beds are dominated by ornate 'metapolygnthids' that would formerly have been collectively referred to Metapolygnathus primitius, a species long known to straddle the CNB. Within this lower part of the section, they resemble forms that have been separated as Metapolygnathus mersinensis. Slightly higher, forms close to Epigondolella' orchardi and a single Orchardella n. sp. occur. This association can be correlated with the latest Carnian in British Columbia.

Higher in the section, the ammonoid fauna shows a sudden change and is dominated by Tropithisbites. Few tens of metres above, but slightly below the first occurrence of Norian ammonoids Guembelites jandianus and Stikinoceras, two new species of conodonts (Gen et sp. nov. A and B) appear that also occur close to the favoured Carnian/Norian boundary at Black Bear Ridge, British Columbia. Stratigraphically higher collections continue to be dominated by forms close to M. mersinensis and E. orchardi. after BC's own Mike Orchard.

The best exposure of the Kerri Zone is on the western side of the West Union Canyon. Ammonoids, dominated by Guembelites and Stikinoceras div. sp., have been collected from several fossil-bearing levels. Conodont faunas replicate those of the east section. The collected ammonoids fit perfectly well with the faunas described by Silberling in 1959, but they differ somewhat from coeval faunas of the Tethys and Canada.

The genus Gonionotites, very common in the Tethys and British Columbia, is for the moment unknown in Nevada. More in general, the Upper Carnian faunas are dominated by Tropitidae, while Juvavitidae are lacking.

After years of reading about the correlation between British Columbia and Nevada, I had the very great pleasure of walking through these same sections in October 2019 with members of the Vancouver Paleontological Society and Vancouver Island Palaeontological Society. It was with that same crew that I'd originally explored fossil sites in the Canadian Rockies in the early 2000s. Those early trips led to paper after paper and the exciting revelations that inspired our Nevada adventure.

Tuesday, October 11, 2022

CRANBROOK EAGER FORMATION: TUZOIA

This specimen of the arthropod Tuzoia sp. is from the Lower Cambrian Eager Formation of British Columbia. 

Tuzoia is an extinct genus of large bivalved arthropod known from Early to Middle Cambrian marine environments in what is now the Burgess Shale, Emu Bay Shale, Kaili, the Rockslide Formation, the Spence Shale, Wheeler Formation, and Marjum Formation, and the Kinzers Formation. 

As you can see here, they are also found in the Lower Cambrian Eager Formation near Cranbrook British Columbia. 

This particular specimen is from the Rifle Range outcrop near Cranbrook where you can also find numerous fragments and complete specimens of the olenellid trilobites Ollenellus sp. and the larger, more robust Wanneria dunnae, along with Mesonacis eagerensis (Best, 1952).

The site outcrops at a few locations as you head east out of Cranbrook towards Fort Steele. The first trilobites were discovered with the building of the Kootenay Highway connecting Cranbrook to Fort Steele and beyond. Several other localities, including the outcrops at the Silhouette Rife Range — which is literally on a Rifle Range where folks go to shoot at things — is a shade older than the Middle Cambrian Burgess Shale but the fauna here is much less varied. 

The site has been known and collected since the 1920s. Back in the day, fossil collecting was a family affair with folks heading out in their lightly coloured finery to picnic and surface collect the eroding exposures. Cranbrook local, Clement Hungerford Pollen was an engineer and avocational palaeontologist. He promoted collecting the exposures of the Eager Formation around 1921. As a pedigreed Englishman of considerable means, he had invested in the Kootenay Central Railway, revitalizing the town by opening up railway access within the region.

Wednesday, July 27, 2022

LYSAKER MEMBER TRILOBITE

Niobe schmidti (Balashova, 1976)
This gorgeous trilobite is an exceptionally well-preserved Niobe schmidti (Balashova, 1976) from middle Ordovician limestone deposits of the Huk Formation, Lysaker member near Oslo, Norway. 

The limestones of the Huk Formation have an extreme geological history and fossils from this formation are usually very difficult to prepare. 

The beige/grey limestones are often heavily cemented to the shelly material, which can be quite fragile.

The rich chocolate coloured specimen you see here was no exception. It presented many challenges in its 26 hours of preparation but each of these was overcome by the patience and skill of Paul Freitag Wolvers at Freitag Fossils. 

I have added a link below with a series of photos so you can walk through the preparation process step by step with Paul. If you have a special specimen you would like prepped, I highly recommend you contact him. His work is outstanding.

Superb prep of this Niobe schmidti (Balashova, 1976)
The shell was partly hollow, very fragile and stuck firmly to the matrix. The positive was assembled from two pieces and much of the shell of the left half of the trilobite had to be transferred over from the negative — no small feat. 

Despite these challenges, the final result is superb. This Niobe schmidti is a museum-quality specimen with exquisite preservation. You can clearly see the lovely terrace lines, pores and eye lenses are excellent to study.  

This specimen hails from the middle Ordovician. The Ordovician lasted almost 45 million years, beginning 488.3 million years ago and ending 443.7 million years ago. 

It was the time in our Earth's history when the area north of the tropics was almost entirely underwater and most of the world's land was collected into the southern supercontinent of Gondwana. Throughout the Ordovician, Gondwana slowly shifted towards the South Pole and much of it remained submerged under an ancient ocean.

Niobe schmidti (Balashova, 1976)
At the time that this fellow was making a living in our ancient seas, he would have been joined by a diverse community of marine invertebrates —graptolites, fellow trilobites, brachiopods and the early vertebrate conodonts. 

These marine communities were joined by red and green algae, primitive fish, cephalopods, corals, crinoids, and gastropods. 

We also find stunning tetrahedral spores similar to those of primitive land plants which tell us who was living on the land at the time.

One of the first specimens of this lovely species I had the pleasure to see was from the Voybokalo Quarry near St. Petersburg in Russia. These outcrops are part of the Kunda Horizon, Lower Ordovician, Asaphus expansus zone and run roughly 468 million years old. 

From the Lower to Middle Ordovician, the Earth was enjoying a mild, humid climate — the weather was warm and the atmosphere contained a significant amount of moisture. 

Once Gondwana finally settled on the South Pole during the Upper Ordovician, massive glaciers formed. These drained the shallow seas and ocean levels dropped. By the end of the Ordovician, 60% of all marine invertebrates and 25% of all life on Earth disappeared as part of the Ordovician mass extinction event. We enjoy many of those species now only as fossils and if we are lucky, preserved in remarkable detail.

Photos & collection: Mark Wolvers. Preparation: Paul Freitag, Freitag Fossils. Specimen: 5.5 cm (2.16 inches). You can see some amazing photos of the transformation of this trilobite throughout Paul's preparation process here: https://freitag-fossils.com/en/niobe-schmidti/

If you click on any of the images, you can see them enlarged to take in all the wonderful detail. 

Reference: UCMP Berkeley / https://ucmp.berkeley.edu

Sunday, January 30, 2022

LOWER CAMBRIAN EAGER FORMATION

This specimen of a mature olenellid trilobite, Wanneria dunnae, is from the Lower Cambrian Eager Formation of British Columbia. 

He is from the Rifle Range outcrop near Cranbrook where you can find numerous fragments and complete specimens of the olenellid trilobites Ollenellus sp. and the larger, more robust Wanneria sp. you see here. 

The site outcrops at a few locations as you head east out of Cranbrook towards Fort Steele. 

The first trilobites were discovered with the building of the Kootenay Highway connecting Cranbrook to Fort Steele and beyond. Several other localities, including the outcrops at the Silhouette Rife Range — which is literally on a Rifle Range where folks go to shoot at things — is a shade older than the Middle Cambrian Burgess Shale but the fauna here is much less varied. 

The site has been known and collected since the 1920s. Back in the day, fossil collecting was a family affair with folks heading out in their lightly coloured finery to picnic and surface collect the eroding exposures. Cranbrook local, Clement Hungerford Pollen was an engineer and avocational palaeontologist. 

He promoted collecting the exposures of the Eager Formation around 1921. As a pedigreed Englishman of considerable means, he had invested in the Kootenay Central Railway, revitalizing the town by opening up railway access within the region.

Olenellus ricei, Eager Formation
Olenellus is an extinct genus of redlichiid trilobites, with species of average size (about 5 centimetres or 2.0 inches long). He lived during the Botomian and Toyonian stages, Olenellus-zone, 522 to 510 million years ago, in what is currently North America, part of the paleocontinent Laurentia.

These extinct arthropods are common in Early Cambrian rocks — 542 million to 521 million years old — and thus a useful guide fossil for the Early Cambrian. 

Olenellus had a well-developed semi-circular head, large and crescentic eyes, and a poorly developed, small tail. Telltale features are his fifteen body segments with the third being much longer than the others. The fellow you see had a bit of his tail crushed as he turned to stone.

Trilobites were amongst the earliest fossils with hard skeletons. While they are extinct today, they were the dominant life form at the beginning of the Cambrian and it is what we find as the primary fossil fauna in the Eager Formation. The Eager Formation has produced many beautifully preserved Wanneria, abundant Olellenus and a handful of rare and treasured Tuzoia. The shale matrix lends itself to amazing preservation. The specimens of Wanneria from here are large. Some are up to thirteen centimetres long and ten centimetres wide. You find a mixture of complete specimens and head impressions from years of perfectly preserved moults.