Koshak-Maastrichtian (Cretaceous of Kazakhstan)

Where: Kazakhstan (44.6° N, 51.6° E: paleocoordinates 38.1° N, 45.3° E)

• coordinate stated in text

When: Late/Upper Maastrichtian (70.6 - 66.0 Ma)

Environment/lithology: shallow subtidal; fine-grained, white limestone and marl

• The Maastrichtian is developed in a fine white chalk facies, and displays marked rhythmicity on a decimetre scale, probably representing climatic cyclicity in the Milankovich band. Couplets are defined by burrowed omission surfaces which rest on white chalk, overlain by flaser marl seams the entire section falls within the latests Maastrichtian Belemnella casimirovensis Zone (upper Upper Maastrichtian in the German sense).

• The Maastrichtian chlak is overlian by a 10-20 mm thick flasered grey marl (Bed 8) which rests on an omission surface. Nazarov et al. (1983) recorded an iridium 'spike' within this bed. Thalassinoides burrows (idiomorphic, omission-suite) which contain a dark marl fill, penetrate 0.3 m down into the Maastrichtian Bed 7.

Size class: macrofossils

Primary reference: C. H. Jeffery. 1997. All Change at the Cretaceous-Tertiary Boundary? Echinoids from the Maastrichtian and Danian of the Mangyshlak Peninsula, Kazakhstan. Palaeontology 40(3):659-712 [L. Ivany/P. Wall/P. Wall]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 48022: authorized by Linda Ivany, entered by Patrick Wall on 10.03.2005

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Echinoidea
 Calycina - Phymosomatidae
"Phymosoma granulosum" = Rachiosoma corollare
"Phymosoma granulosum" = Rachiosoma corollare Leske 1778 sea urchin
 Echinoneoida - Conulidae
Conulus magnificus
 Holectypoida -
Galerites stadensis
 Spatangoida - Brissidae
Cyclaster galei n. sp.
Cyclaster galei n. sp. Jeffery 1997 heart urchin
 Holasteroida - Holasteridae
Pseudoffaster caucasicus