Stappogiedde Formation

The Stappogiedde Formation is a geologic formation in Norway, which spans from the late Ediacaran into the early Cambrian, and also preserves fossils dated to the Ediacaran period.

Stappogiedde Formation
Stratigraphic range: Ediacaran - Cambrian 560–530 Ma[1] PreꞒ Ꞓ O S D C P T J K Pg N
Type	Formation
Unit of	Vestertana Group
Sub-units	Manndraperelv, Innerelv and Lillevatn Members[2]
Underlies	Breivik Formation
Overlies	Mortensnes Formation
Thickness	505–530 metres (1,657–1,739 ft)
Lithology
Primary	Sandstone
Other	Shale, Conglomerate, Quartzite, Mudstone, Greywacke
Location
Country	Norway

Geology

The Stappogeidde Formation consists of three members, which are as follows, from the topmost member to the basal most member:

Manndraperelv Member

The Manndraperelv Member is the youngest member of this formation, and is roughly 190 metres (620 ft) at its thickest, and mainly consists of coarse-grained, red quartzite sandstones and conglomerate, which is interbedded with greywacke and mudstone. The lower strata of this member contains occasional Ichnotaxon, which have been noted to be similar to Planolites, and also contains the agglutinated organism, Palaeopascichnus.^[2][3]

Innerelv Member

The Innerelv Member is the middle member of this formation, and is the largest member in terms of thickness, coming in at around 275–300 metres (902–984 ft) thick. Near the base of this member, it mainly consists of green to red shales, which contain occasional interbedded fine-grained, red sandstones. Towards and into the middle, the shales become a more greenish-grey colour, with fine-grained cross-laminated sandstones. At the top of the member, the fine-grained sandstones give way to much thicker interbedded medium to coarse, parallel-laminated sandstone. In exposed areas, the sandstone features rippled tops, and their orientation suggest a southwestern palaeocurrent at the time of deposition. In non-exposed areas, this layer is overlain by a top-most layer of greenish-grey, parallel-laminated siltstones, which are interbedded with fine-grained, ripple-marked sandstone.^[2]

This is also the main fossiliferous member of the whole formation, containing a wide range of discoidal forms.^[2]

Lillevatn Member

The Lillevatn Member is the oldest member of this formation, and is also the smallest, only being 40 metres (130 ft) at its thickest. It mainly consists of a quartz conglomerate, which are overlain by medium-grained, gray sandstones.^[2]

Dating

Using Rubidium–strontium dating on samples collected within the Stappogiedde Formation and other formations within the area, a minimum age of 530±0 Ma had been recovered from samples collected at the top of the formation, dating part of the Manndraperelv member to within the early Cambrian period, and is inline with previous Rb-Sr dating studies.^[4] The maximum age of 560±0 Ma had been recovered from the base of the formation, reaffirming assumptions that the majority of the formation is Ediacaran in age.^[1]

Paleobiota

The Stappogiedde Formation contains a myriad of discoidal forms, from Cyclomedusa being the most common form, to others like Ediacaria and Nimbia occlusa.^[2]

Genera that are not found within the main fossiliferous Innerelv member will be noted as such.

Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon		Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Cnidarian

Genus	Species	Notes	Images
Ediacaria (?)[2]	Ediacaria sp. (?)	Discoid organism, tentative assignment.

incertae sedis

Genus	Species	Notes	Images
Cyclomedusa[2]	Cyclomedusa sp.	Discoid organism.
Hiemalora[2]	Hiemalora sp.	Discoid organism, possibly holdfasts of petalonamids.
Nimbia (?)[2]	N. occlusa (?)	Discoid organism, tentative assignment.
Palaeopascichnus[3]	P. delicatus	Palaeopascichnid organism, found in the Manndraperelv member.
Vendotaenia[3]	Vendotaenia sp.	Ribbon-like organisms.

Flora

Genus	Species	Notes	Images
Beltanella[2]	Beltanella sp.	Cyanobacterial colony, now a junior synonym of Beltanelliformis.
Beltanelliformis	Beltanelliformis sp.	Cyanobacterial colony.

Ichnogenera

Genus	Species	Notes	Images
Arenicolites[2]	Arenicolites isp.	Burrows.
Planolites-like trace fossils [2]	???	Burrows and trace fossils similar to the ichnotaxon Planolites from the Manndraperelv member.
Skolithos[2]	Skolithos isp.	Burrows.

See also

• Earth sciences portal
• Norway portal
• Paleontology portal

• List of fossiliferous stratigraphic units in Norway