The Kem Kem Group (commonly known as the Kem Kem beds) is a geological

group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic iden ...

in the Kem Kem region of eastern Morocco, whose strata date back to the

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

stage of the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

. Its strata are subdivided into two geological formations, with the lower Ifezouane Formation and the upper Aoufous Formation used for the strata on the eastern side of the Atlas Mountains ( Tinghir), with the Gara Sbaa Formation and Douira Formation used in the southern

Tafilalt Tafilalt or Tafilet (), historically Sijilmasa, is a region of Morocco, centered on its largest oasis. Etymology There are many speculations regarding the origin of the word "Tafilalt", however it is known that Tafilalt is a Berber word meaning ...

region. It is exposed on an escarpment along the

Algeria–Morocco border The Algeria–Morocco border is 1,427 km (887 mi) in length and runs from Mediterranean Sea in the north, to the tripoint with Western Sahara in the south. The border has been officially closed to all travel since 1994, although clandes ...

. The unit unconformably overlies

Paleozoic The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...

marine units of

Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ...

Silurian The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of t ...

and

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

ages and is itself capped by

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

platform rock of Cenomanian-

Turonian The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...

age. It primarily consists of freshwater and estuarine deltaic deposits. The lower Gara Sbaa Formation primarily consists of fine and medium grained

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

, while the Douira Formation consists of fining-upward, coarse-to-fine grained sandstones intercalated with

siltstones Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed ...

, variegated

mudstones Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York ...

, and occasional thin gypsiferous

evaporite An evaporite () is a water- soluble sedimentary mineral deposit that results from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporite deposits: marine, which can also be described as oce ...

s. Dinosaur remains are among the fossils that have been recovered from the group.Weishampel, David B; ''et al.'' (2004). "Dinosaur distribution (Late Cretaceous, Africa)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 604-605. . Recent fossil evidence in the form of isolated large abelisaurid bones and comparisons with other similarly aged deposits elsewhere in Africa indicates that the fauna of the Kem Kem Group (specifically in regard to the numerous predatory theropod

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

s) may have been mixed together due to the harsh and changing geology of the region, when in reality they would likely have preferred separate habitats and likely would have been separated by millions of years. Although preserving a freshwater habitat located near a river delta (with some estuarine influence that increased over time as the sea level rose), the Kem Kem deposits were quickly submerged by the sea during the

Cenomanian-Turonian boundary event The Cenomanian-Turonian boundary event, also known as the Cenomanian-Turonian extinction, Cenomanian-Turonian Oceanic Anoxic Event ( OAE 2), and referred to also as the Bonarelli Event or Level, was an anoxic extinction event in the Cretaceous p ...

, and are thus overlaid by the marine deposits of the younger latest

and early-mid

-aged Akrabou Formation, which was formerly also considered a member of the Kem Kem Group, but has been differentiated from it in more recent studies due to their differing paleoenvironments.

Vertebrate paleofauna

Cartilaginous fish

Ray-finned fish

Lobe-finned fish

Amphibians

Lizards and snakes

Plesiosaurs

Turtles

Crocodylomorphs

A tooth enamel identified as

cf. The abbreviation cf. (short for either Latin or , both meaning 'compare') is generally used in writing to refer the reader to other material to make a comparison with the topic being discussed. However some sources offer differing or even contr ...

'' Sarcosuchus'' was discovered from the Ifezouane Formation.

Dinosaurs

Indeterminate lithostrotian remains once misattributed to the Titanosauridae are present in the province of Ksar-es-Souk, Morocco.

Ornithischians

Sauropods

Theropods

Pterosaurs

References

{{Reflist Geologic groups of Africa Upper Cretaceous Series of Africa Cenomanian Stage Cretaceous Morocco Sandstone groups Paleontology in Morocco Algeria–Morocco border