The Barun Goyot Formation (also known as Baruungoyot Formation ) is a geological formation dating to the Late Cretaceous Period . It is located within and is widely represented in the Gobi Desert Basin, in the Ömnögovi Province of Mongolia.
7-807: It was previously known as the Lower Nemegt Beds occurring beneath the Nemegt Formation and above the Djadokhta Formation . It has been suggested that the Djadokhta and Barun Goyot Formations are lower and upper parts, respectively, of the same lithological unit and the boundary between the two does not exist. The stratotype of the Barun Goyot Formation is the Khulsan locality, east of Nemegt. At Nemegt, only
14-537: Is a geological formation in the Gobi Desert of Mongolia , dating to the Late Cretaceous . The formation consists of river channel sediments and contains fossils of fish , turtles , crocodilians , and a diverse fauna of dinosaurs , including birds. The Nemegt Formation is composed of mudstones and sandstones that were deposited by ancient lakes, streams, and flood plains. The Altan Uul locality
21-751: The Barun Goyot Formation . Interfingering has been noted at the stratotype (Red Walls) and Hermiin Tsav. There has been no absolute dating of the Nemegt Formation. Historically the Nemegt has been considered late Campanian to Maastrichtian, based on comparisons of fossils present, but no exact dating has been performed. The age for the underlying Baruungoyot Formation (= Svita) has been suggested as Santonian to Campanian , and Shuvalov (2000) found K-Ar dating of basalts that they referred to
28-402: The Nemegt Formation into three informal members. The lower member is dominated by fluvial deposits, while middle and upper members consist of alluvial plain , paludal , lacustrine , and fluvial deposits. The colour of the sediments is usually light grey to tan in colour in comparison to the typically red colour of the underlying Barun Goyot Formation. It overlies and sometimes interfingers with
35-417: The forests of the Nemegt were thickly wooded, with a high canopy formed by tall conifer trees. When examined, the rock facies of this formation suggest the presence of stream and river channels, mudflats, and shallow lakes. Sediments also indicate that there existed a rich habitat, offering diverse food in abundant amounts that could sustain massive Cretaceous dinosaurs. The most recent stratigraphy divides
42-738: The uppermost barungoyotian beds are visible. The Red Beds of Khermeen Tsav are also considered part of the Barun Goyot Formation. It is approximately 110 metres (360 ft) in thickness, and was laid down roughly 72-71 million years ago. Given the new date for the start of the Maastrichtian (72.1 MYA) a basal Maastrichtian age seems probable. The Barun Goyot Formation preserves an environment of sand dunes , created from wind-eroded rocks ( aeolian dunes). Estesia Estesia mongoliensis An anguimorph Proplatynotia Proplatynotia longirostrata Nemegt Formation The Nemegt Formation (also known as Nemegtskaya Svita )
49-418: Was described by Michael Novacek as "a canyon carved out of a very rich series of sedimentary rocks" with "steep cliffs and narrow washes". The climate associated with it was wetter than when preceding formations were deposited; there seems to have existed at least some degree of forest cover . Fossilized trunks have been also found. These petrified wood, and the remains of Araucariaceae conifers indicate that
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