Wednesday 27 July 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