Ustʹ Pinega Formation

64°9′0.000″N 41°55′59.988″E The Ustʹ Pinega Formation is an Upper Ediacaran geological formation exposed along the banks of the Syuzma and Onega Rivers in Arkhangelsk Oblast, northwestern Russia,^[3] and spans from around 580 Ma to 550 Ma, with fossilferous stones restricted to between 565 and 555 Ma.

Ustʹ Pinega Formation
Stratigraphic range: Ediacaran 580–550 Ma[1] PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological Formation
Sub-units	Zimnie Gory Formation (Zimnie Gory and Vaizitsa beds) Verkhovka Formation (Vaizitsa, Syuzma and Verkhovka beds) Lyamtsa Formation (Arkhangelsk and Lyamtsa beds)[2]
Underlies	Lyubim Formation
Overlies	Pletenev Formation
Thickness	487.3 m (1,598 ft)[1]
Lithology
Primary	Argillite
Other	Sandstone, Siltstone, Clay
Location
Region	Arkhangelsk Oblast
Country	Russia
Extent	300+ km [1]

It also preserves a wealth of rare Ediacaran fossils, like Zolotytsia, Ventogyrus and Bomakellia.

Dating

The Ustʹ Pinega Formation is relatively large, and using zircon U-Pb dating, a date of 550±2 Ma had be recovered for the top of the formtion,^[4] whilst the known base of the formation is restricted to 580±0 Ma.^[4][1]

As for the lower and upper dates of the fossiliferous units within the formtaion, using the Rb–Sr dating method, the lowest fossiliferous unit of the Ustʹ Pinega Formation has been dated to 565±9 Ma,^[1] whilst the upper-most fossiliferous unit was dated using zircon U-Pb dating, which had recovered a date of 555±3 Ma.^[5]

Paleobiota

The Ustʹ Pinega Formation is home to many rare and common Ediacaran fauna, from the well known motile forms such as Dickinsonia and Kimberella,^[6] to the rarer, more elusive forms like Ventogyrus and Zolotytsia. All forms within this formation are preserved in layers of ash beds, which are not only good at preserving the fine exterior details of organisms, but also their internals, like Burykhia.^[7]

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.

Proarticulata

Genus	Species	Notes	Images
Andiva[8]	A. ivantsovi	Elongated oval motile organism.
Archaeaspinus[9]	A. fedonkini	Oval motile organism.
Armillifera[3]	A. parva	Elongated oval motile organism.
Cephalonega[3]	C. stepanovi	Oval motile organism.
Cyanorus[9]	C. singularis	Elongated motile organism.
Dickinsonia[3][5]	Dickinsonia sp.	Oval to elongated motile organism.
Ivovicia[10]	I. rugulosa	Elongated oval motile organism.
Karakhtia[11]	K. nessovi	Oval motile organism.
Keretsa[12]	K. brutoni	Elongated motile organism.
Lossinia[10]	L. lissetskii	Elongated motile organism.
Ovatoscutum[3][5]	O. concentricum	Rounded motile organism.
Palaeoplatoda[3][13]	P. segmentata	Elongated motile organism.
Paravendia[9]	P. janae	Elongated motile organism.
Vendia[3][5]	V. rachiata	Elongated motile organism.
Yorgia[5]	Y. waggoneri	Oval motile organism.

Petalonamae

Genus	Species	Notes	Images
Bomakellia[14]	B. kelleri	Sessile frondose organism.
Charnia[3][5]	Charnia sp.	Sessile frondose organism.
Charniodiscus[3]	Charniodiscus sp.	Sessile frondose organism.
Pteridinium[3]	Pteridinium sp.	Sessile frondose organism.

Trilobozoan

Genus	Species	Notes	Images
Albumares[3]	A. brunsae	Tri-radial organism.
Anfesta[3][5]	A. stankovskii	Tri-radial organism.
Tribrachidium[3][5]	T. heraldicum	Tri-radial organism.

Cnidarian

Genus	Species	Notes	Images
Bonata[3]	B. septata	Discoid organism.
Brachina[3]	Brachina sp.	Discoid organism.
Ediacaria[3][5]	Ediacaria sp.	Discoid organism.
Eoporpita[3][5]	E. medusa.	Discoid organism.
Inaria[5]	I. karli	Sac-like organism.
Medusinites[3]	Medusinites sp.	Discoid organism.
Staurinidia[3][5]	S. crucicula	Discoid organism.
Tirasiana[3]	Tirasiana sp.	Discoid organism.
Vendoconularia[15]	V. triradiata	Hexagonal tubular organism.
Zolotytsia	Z. biserialis	Deformed mass of ovals along a mid-line groove.

Chordata

Genus	Species	Notes	Images
Burykhia[7]	B. hunti	Sac-like organism, possible tunicate.
Yarnemia[16]	Y. ascidiformis	Sac-like organism, possible tunicate.

Annelida

Genus	Species	Notes	Images
Calyptrina[3]	C. striata	Tubular organism.

incertae sedis

Genus	Species	Notes	Images
Catellichnus	Catellichnus sp.	Palaeopascichnid organism.
Cyclomedusa[3][5]	Cyclomedusa sp.	Discoid organism.
Hiemalora[3][5]	Hiemalora sp.	Discoid organism, possibly holdfasts of petalonamids.
Kimberella[6][5]	Kimberella sp.	Egg-shaped organism, possible mollusc.
Mawsonites[5]	M. spriggi	Discoid organism.
Nimbia[3][5]	N. occlusa	Discoid organism.
Orbisiana[3]	Orbisiana sp.	Palaeopascichnid organism.
Palaeopascichnus[3][5]	Palaeopascichnus sp.	Palaeopascichnid organism.
Parvancorina[3][5]	P. sagitta	Anchor-shaped organism, possible mollusc or arthropod.
Redkinia[3]	Redkinia sp.	Rod-like fossil, possibly mouth parts of a arthropod.
Solza[11]	S. margarita	Egg-shaped organism.
Vendotaenid[3]	Vendotaenid	Ribbon-like fossils.
Ventogyrus	V. chistyakovi	Tri-radial egg-shaped organism, tethered to the seafloor.

Flora

Genus	Species	Notes	Images
Archyfasma[17]	A. dimera A. lamellata	Branching macroalgae.
Beltanelliformis[3][5]	Beltaneillformis sp.	Cyanobacterial colony.
Eoholynia[17]	E. fruticulosa	Branching macroalgae.
Favosiphycus[17]	F. wukii	Flattened thallus crust-like, consisting of densely packed cells.
Gandvikia[17]	G. caudata	Ribbon-shaped macroalgae.
Chuaria[3]	Chuaria sp.	Elongated organism.
Mezenia[3]	M. kossovoyi	Sausage shaped macroalgae.
Serebrina[18]	S. crustacea	Encrusting macroalgae.

Ichnogenera

Genus	Species	Notes	Images
Epibaion	Epibaion sp.	Feeding traces of proarticulates.
Kimberichnus[19][5]	Kimberichnus sp.	Feeding traces of Kimberella.
Nenoxites[3]	Nenoxites sp.	Movement traces.
Neonereites[3]	Neonereites sp.	Burrows.
Planolites[3]	Planolites sp.	Burrows.

See also

• List of fossiliferous stratigraphic units in Russia