Trilobite fossils are found in different rocks (matrix), from very hard Moroccan or Scandinavian matrix to soft shale, typical for some localities in USA. Each matrix and different species - different factors demand a different preparation approach, but what all trilobites have in common is how they are found - by splitting and breaking rocks! There is a lot of hard work involved in finding trilobites...
So usually trilobites are found in two or more parts of the rock, because usually the only way to find one is to break the rock! All the parts are then carefully glued back and carefully preped... Some are easy to prep, but it takes experience and special equipment/tools, other are difficult and demand more time and skills.
Another thing almost all fossils have in common is - careful preparation work takes a lot of time. Not a rule however, a simple example, Eldredgeops rana from NY in soft shale can be cleaned (sandblasted) in a matter of minutes, while a similar species from Morocco in medium hard matrix will take many hours of careful cleaning. A trilobite in a vey hard matrix or a species with delicate spines demands even more preparation time...
In Morocco trilobites are found in remote couches where many layers are commercially excavated for trilobites and the location can only be reached using an ATV. Thousands of Moroccan families survive from this activity. Countless new trilobite species, new to science, are found and described thanks to commercial Moroccan diggers and preparators. If you have any experience collecting in the field, you can imagine digging and splitting numerous rocks and detecting a cross section of a promising specimen among other remains and fragments is not an easy job! Hats off to moroccan collectors, some are true experts for finding and preping these tiny prehistoric creatures! Identification of the species hidding in the matrix can be made just by looking at the cross section, matrix type and details shown in the break...
The point of preparation process is to remove bits of matrix without damaging the body/exoskeleton of the trilobite hidden in matrix. This process is normally done with an air scribe and needles and a micro-sandblaster unit. It's quite a slow process that can take from 10 to 30 hours for a simple small trilobite species (some of these are only 1 - 2 cm long), and A LOT more for some spiny or larger species...
Powered by compressed air an air-scribe operates like a miniature jackhammer, chipping through the rock that covers the fossils. Too much force or a simple mistake and parts of fossil chip away too. When the matrix is thinned sufficiently, the air scribe’s impacts often cause the last layers of rock to pop off the fossils, unless the matrix is sticky and extreme care is needed removing the last micrometers of matrix. Air-scribes of "different sizes" can be used for different jobs, different stone hardness, preservation... Mostly you have to move in close to get separation between the fossil and matrix, especially if the matrix is sticky or softer. Hard to give an exact estimate, but sometimes that means working tenth and hundredths of a millimeter away from the trilobite exoskeleton and removing matrix bit by bit. It involves a lot of time and patience... For more delicate structures, such as long fragile 3D preped spines a micro-sandblaster unit is used...
I have organised few workshops with the solely intention of bring the young people to the fossils. Show what you can reach with some patience and effort. It has been a great time and lot of fun show to people and attend questions of how to find and prepare fossils.
The workshop i use for alive preparation consist of a microscope, a silent compressor, and air chisels. People really get stunned to see how is like to remove the rock that surrounds a stinct animal. I been performing in geology days, in front of schools for educational purposes and in mineral shows.
Why a geology center in Slemmestad?
Slemmestad is located in the pearl of Oslo Fiord and has for over a hundred years been known as a treasure chest for those interested in stone and fossils. Within a small area there are remains of life through a vast time span and countless types of rocks and minerals. It is first and foremost where the exciting geology is to be found, but also visit the geology center to watch exhibitions of the area's fossils, rocks and minerals.
Slemmestad is thus a central part of the Oslo field and has a particularly complex geology. Nest after Kolsås is probably this place in Norway most used for geological studies. Here you will find a rich range of fossils and a wide range of rocks from ancient times and ancient times.
The Oslo field, the area around the west and north of Oslofjorden, from Langesund in the south to Mjøsa in the north. The Oslo field tells the story of the period from 545 to 280 million years ago, which has not been preserved elsewhere in Norway. The reason for this is that the whole field dropped hundreds of meters into a grave, while the areas around were worn down to the base mountain.
In Slemmestad there are different rocks. Some are so-called sedimentary, that is, they are formed by sand and gravel on the seabed. These often contain fossils. Others are volcanic and are formed by more dramatic events than we are used to here in Slemmestad nowadays. In addition, many different stones have been moved here with the ice a few tens of thousands of years ago. The beach at Odden is a showcase for different pebbles of different rocks from different places in Norway.
Some places in Slemmestad are almost too good to be true! In the center there is the schoolbook example. Here lies the ancient mountain bottom at the bottom, and as the layers of a soft cake lie limestone and slate from the cambrium in the middle and volcanic stone from the ceiling on the top. In most other places, wear, displacements and earthquakes have "rotten to" the order, but here you can see the theory in practice: the oldest is at the bottom, and then younger and younger stones come in ascending order over a 630 million year span.
The fossils, which may be the most, get fascinated by, there's almost no matter where you turn and turn. It's just a matter of knowing what to look for! The fossils here in the area originate from the periods of Cambodia, Ordovicium and Silur, ranging from 541 million to 419 million years ago. At that time, Slemmestad was a seabed in a relatively shallow sea. Here it was ravaging animals and plants. Some resemble those we know today, while others look strangers alike.
The most famous fossils from Slemmestad are squid and trilobites. The trilobites were very common arthropods related to shrimp and crayfish. Together with them lived octopuses, snails and sea lilies. Most discussed in recent years are "football field fossils". It's a relatively newly discovered and unique discovery: A giant premiered seabed surface containing thousands of octopus fossils. In retrospect, a smaller part of the same surface has been discovered behind the local gas station. Both surfaces are full of octopus and are fascinating sight.
Slemmestad geology center received the happy message on 7 December 2016 that we were awarded NOK 600,000, - for preparation and dissemination of Slemmestad's unique geology with focus on fossils. In the summer of 2016 a large stone block was taken out of the fossil valley. This was taken to the library. There are lots of fossils in the stone block. In parallel, the work was to establish a temporary geological center on the lawn, without initiation. Here, there would be a separate laboratory for fossil preparation, an exhibition and dissemination room and outdoor area organized for teaching. Together we have called these three elements Trilobox. The money from Sparebankstiftelsen DNB would help us develop this concept.
At the end of May 2017 we received the money and the work of excavation and preparation could take place. Trilobites of Norway start with the demanding job of getting the fossils out of the particularly hard limestone, Eventually, the one trilobite saw the second day's light. Just over 1 1/2 years later, the geology center is proud owner of 35 beautiful black trilobites from Slemmestad and boasts Norway's finest and only collection of trilobites of its kind. Through his creativity and effort, Maximo has developed new techniques to extract fossils from Slemmestad in a way that science has never seen. During the last 200 years of research on trilobites in Norway, the fossils have never been prepared from the stone in such detail and with so much patience. Maximo is definitely the best to prepare fossils from the Oslo field in Norway today.