Likelihood of Locality
When planning a field season, palaeontologists often start by looking for rocks of a desired age and kind. For example, mammal fossils are usually recovered from rocks that were formed from river or lake sediments from the last 65 million years.
How do palaeontologists know where to go in order to look for the desired rocks? They review the geology of an area by consulting the relevant geologic literature, and studying topographic/geological maps and aerial photos.
Natalia Rybczynski and Liz Ross consult with helicopter pilot Gerry Greeing. They are discussing likely locations for potentially fossiliferous outcrops in the Haughton Crater.
Finding the right kind of rock is only the first step. It can sometimes take a lot of prospecting to find an area that yields fossils. It is common for researchers to return to a fossil-yielding area year after year because erosion is ongoing and may expose new fossils.
A similar strategy led Natalia Rybczynski to organize the Arctic expeditions that found the fossil of Puijila darwini. The lake deposits of the Haughton Crater were known to have yielded an impressive assortment of mammal fossils in the 1970s and 1980s. Rybczynski even invited vertebrate palaeontologist Mary Dawson on the expeditions—Dawson had led much of the pioneering work in the crater and was able to point out previous localities.
Navigating the North
Remoteness and severe weather make palaeontological research in the High Arctic especially challenging.
Natalia and Liz in a Twin Otter plane, on their way out of the Haughton Crater at the end of the first expedition.
A lack of roads makes small planes and helicopters essential for Arctic research. Load limits can make packing a challenge! Weight and space restrictions are constant concerns. Only the most necessary equipment, food, water and personal gear can be brought, and emergencies and the unexpected must also be considered. Fortunately, room for fossils opens up as the food supply dwindles.
Arctic weather can vary wildly, ranging from bright sunny days to violent winds and snow. Planes are able to fly only when weather permits. Because of the variability of Arctic weather, field teams often face unforeseen delays. Emergency food and water are indispensable.
Exploring the Exposures
Prospecting for fossils is time-consuming and requires a lot of patience. Days, or even weeks, can go by without finding a single significant fossil. When prospecting for fossils, the field team often splits up into smaller groups in order to cover more ground.
One of Puijila's vertebrae at the moment of its discovery. It is about 3 cm long.
Fossils are often covered in sediment (matrix) or only partially exposed. They can be incomplete, crushed, fractured and fragmented. A useful and common technique for spotting fossils is to have a "search image" in mind. The search image is formed by visualizing relevant shapes and characteristics, such as bone contours, size, colour and porosity. Finding fossils takes luck and skill!
In this sequence of photos, Mary Dawson shows initial disbelief that the fossil that was just found is the missing braincase. She wets it to see it better and looks closely. See her delighted reaction when she confirms that it is the sought-after braincase.
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Often, when a fossil is found it is fragmented, crushed and incomplete. In the Arctic, fossils can be further damaged by the movement of the upper layers of the ground as it cycles through seasonal freezing and thawing. All things considered, it is truly remarkable that the fossil skeleton of Puijila was discovered, never mind that it was 65% complete!
The Haughton Formation Fossil Wallet Guide
The Haughton Formation is rich in high-quality fossils. Fossils often shed light on the history of life on our planet and, thus, are exceptionally valuable. It is important to use proper methods when handling any fossils that are found. Because palaeontologists are not the only people finding fossils in the Haughton Formation, Rybczynski and Gilbert developed a handy, wallet-sized guide. It offers simple, step-by-step advice on doing the right things to protect the fossil and the information that it offers.