Name: Sirius Passet Fm.
Location: Greenland
Age: Lower Cambrian

Location

The Sirius Passet fauna is found at the base of the Buen Formation, which outcrops on the eastern shore of JP Koch Fjordon, North Greenland (see figure 1). The locality is named after the Sirius Sledge Patrol that operates in this part of Greenland, and was discovered in 1984, by A. Higgins of the Geological Survey of Greenland.

Fig. 1: Locality map showing approximate location of the Sirius Passet location on the eastern side of J. P. Koch Fjord (location indicated by rectangle). Map taken, with permission, from http://www.palaeos.com/Palaeozoic/Cambrian/Sirius_Passet.html

Three expeditions mounted by John Peel and Simon Conway Morris (in 1989, 1991 and 1994) have resulted in the accumulation of approximately 10,000 fossil specimens from this locality.

The Sirius Passet fauna is recognised as a Lagerstätte (meaning "resting place" in German). The term lagerstätte must be qualified for use in a palaeontological context (Shields, 1998). Two divisions are used, Konzentrat-Lagerstätten (which signifies a deposit with a particular concentration of disarticulated organic hard parts, such as a bone bed), and Konservat-Lagerstätten (for exceptional preservational cases, where the soft parts of organisms are preserved as impressions). The Sirius Passet fauna therefore represents a Konservat-Lagerstätte.

Conway Morris (1998) noted that in the palaeotectonic reconstruction of Laurentia, Sirius Passet was at a similar latitude to the Burgess Shale locality (albeit on the other (southern) side of the palaeoequator) in the Cambrian. He also stated that the other major Burgess Shale-type fauna from the Cambrian of Laurentia are arranged concentrically around the palaeoequator, presumably indicative of the necessarily higher sea level required to generate marine deposits on what is now land.