| Buen Formation | |
| Type: | Formation |
| Age: | Cambrian Series 2 (Atdabanian) ~ |
| Period: | Cambrian |
| Prilithology: | Mudstone |
| Otherlithology: | Sandstone, shale |
| Region: | Peary Land |
| Country: | Greenland |
| Coordinates: | 83.1°N -33.8°W |
| Paleocoordinates: | -22.1°N -49°W |
| Unitof: | Sirius Passet |
| Subunits: | Upper & lower members |
| Underlies: | Hans Tavsen icecap |
| Overlies: | Portfjeld Formation |
| Thickness: | Up to 700m (2,300feet) |
| Extent: | Franklinian Basin |
| Location Ts: | Southern Peary Land |
The Buen Formation is a geologic formation and Lagerstätte in Peary Land, North Greenland. The shale preserves fossils dating back to the Early Cambrian period (Atdabanian in the local timescale, about 520 to 513 Ma).[1]
The oldest Cambrian series of the area was deposited in the Franklinian Basin and is poorly exposed in fragmentary, heavily metamorphosed outcrops in Peary Land. It was emplaced during the Ellesmerian orogeny.[2] [3]
During the Cambrian, Greenland was located in the southern tropical to temperate region. The Buen Formation forms part of the southern shelf succession of the Franklinian Basin of North Greenland and the Canadian Arctic Islands. The formation, approximately 325m (1,066feet) thick, consists of a lower, sand−dominated, member overlain by an upper member dominated by dark grey−green mudstones and siltstones in its type area in southern Peary Land. It thickens to around 700m (2,300feet) in northern Peary Land where it comprises a mud−rich transitional succession into deep water trough deposits of the Polkorridoren Group. Dark grey to black mudstones form part of this transitional succession from the shelf to the slope. To the south they lie in faulted contact with pale dolomites of the underlying Portfjeld Formation, and to the north with bioturbated mudstones and sandstones of the Buen Formation.[4]
The following fossils have been reported from the formation:[1]
| Annelids | Phragmochaeta canicularis | align=center | [5] | |
| Arthropods | Buenaspis forteyi | align=center | ||
| Buenellus | ||||
| Aaveqaspis | ||||
| Kerygmachela | ||||
| Tamisiocaris | ||||
| Limniphacos | ||||
| Waptia | ||||
| Kleptothule rasmusseni | [6] | |||
| Isoxys volucris | ||||
| Hadranax augustus | ||||
| Pauloterminus spinodorsalis | ||||
| Molluscs | Halkieria evangelista | |||
| Demosponges | Choia hindei | |||
| Others | Heliosphaeridium dissimilare | |||
| Trapezovitus malinkyi | ||||
| Kalaallitia myliuserichseni | ||||
| Nasaaraqia hyptiotheciformis | ||||
| Nevadotheca boerglumensis | ||||
| Sullulika broenlundi | ||||
| Alutella siku | align=center | [7] | ||