Early Eocene
In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...
(
Ypresian
In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...
geologic formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...
in the
Osh Region
Osh is a Regions of Kyrgyzstan, region of Kyrgyzstan. Its capital is Osh, which is not part of the region. It is bounded (clockwise) by Jalal-Abad Region, Naryn Region, China (Xinjiang), Tajikistan (Districts under Central Government Jurisdiction ...
of southwestern
Kyrgyzstan
Kyrgyzstan, officially the Kyrgyz Republic, is a landlocked country in Central Asia lying in the Tian Shan and Pamir Mountains, Pamir mountain ranges. Bishkek is the Capital city, capital and List of cities in Kyrgyzstan, largest city. Kyrgyz ...
. The formation has provided many
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...
s of
mammal
A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...
s,
lizard
Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...
s,
turtle
Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...
s and
snake
Snakes are elongated limbless reptiles of the suborder Serpentes (). Cladistically squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales much like other members of the group. Many species of snakes have s ...
s.Alai Beds at
Fossilworks
Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world.
History
Fossilworks was cr ...
.org
Description
The Paleogene Alai Beds have a limited distribution, and are restricted to the northern slope of Aktash Range, formed by
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 ...
rocks, which is one of the foothills of the
Turkestan Range
One of the northern extensions of the Pamir-Alay system, the Turkestan Range (; ; ; ) stretches for a total length of 340 km from the Alay Mountains on the border of Kyrgyzstan with Tajikistan to the Samarkand oasis in Uzbekistan. It runs in ...
. The Paleogene deposits on the Aktash Range are badly exposed, they can be observed only in three
outcrop
An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth and other terrestrial planets.
Features
Outcrops do not cover the majority of the Earth's land surface because in most p ...
s, separated by short distances about . Despite their close position, the Paleogene deposits in these outcrops are varied greatly in composition and thickness of layers.Averianov, 1994a, p.399
The lower Alai Beds contain of silts and siltstones, and the upper part comprises
oyster
Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but no ...
-bearing
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) ...
s of which are exposed. At the base of the Upper Alai Beds there is a layer of conglomerate which produces a number of marine vertebrates, but a few terrestrial vertebrates including mammals. The section I1 is more complete and has a greater thickness, but produces a few shark teeth only. The third Paleogene section, where the mammal bearing locality Andarak 2 is located, has a much greater thickness of sands of the lower Alai Beds (more than of visible thickness) with some horizons of oyster-bearing conglomerates.Averianov, 1994a, p.400
Ieper Group
The Ieper Group (; ) is a group (stratigraphy), group of stratum, rock strata in the Subsurface (geology), subsurface of northwest Belgium. The group is subdivided into three marine (ocean), marine formation (stratigraphy), formations, all formed ...
of Belgium
**
Fur Formation
The Fur Formation is a marine geological formation of Ypresian ( Lower Eocene Epoch, c. 56.0-54.5 Ma) age which crops out in the Limfjord region of northern Denmark from Silstrup via Mors and Fur to Ertebølle, and can be seen in many cliffs and ...
of Denmark
**
London Clay Formation
The London Clay Formation is a marine geological formation of Ypresian (early Eocene Epoch, c. 54-50 million years ago) age which crops out in the southeast of England. The London Clay is well known for its fossil content. The fossils from the ...
Nanjemoy Formation
The Nanjemoy Formation is a Formation (geology), geologic formation pertaining to both the Wilcox Group and the Pamunkey Group of the eastern United States, stretching across the states of Virginia, Maryland, and the District of Columbia. The f ...
of the eastern United States
**
Wasatch Formation
The Wasatch Formation (Tw)Shroba & Scott, 2001, p.3 is an extensive highly fossiliferous Formation (geology), geologic formation stretching across several basins in Idaho, Montana, Wyoming, Utah and western Colorado.Itaboraian formations
**
Itaboraí Formation
The Itaboraí Formation () is a highly list of fossiliferous stratigraphic units in Brazil, fossiliferous geologic Formation (geology), formation and LagerstätteKellner & Campos, 1999, p.399 of the Itaboraí Basin in Rio de Janeiro (state), Rio d ...
of Brazil
**
Laguna del Hunco Formation
The Laguna del Hunco Formation or Laguna del Hunco Tuff () is a localized Early Eocene (Itaboraian in the SALMA classification) fossiliferous geological formation of the Cañadón Asfalto Basin in central Patagonia, Argentina. The thick formati ...
of Argentina
References
Bibliography
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* {{cite journal , last=Averianov , first=A. O , year=1994b , title=A new species of ''Sarcodon'' (Mammalia, Palaeoryctoidea) from the Lower Eocene of Kirgizia , journal=
Geobios
Geobios is an academic journal published bimonthly by the publishing house Elsevier. Geobios is an international journal of paleontology, focusing on the areas of palaeobiology, palaeoecology, palaeobiogeography, stratigraphy and biogeochemistry ...