Velociraptor
Djadochta Formation

Known specimens of Velociraptor mongoliensis have been recovered from the Djadochta Formation (also spelled Djadokhta), in the Mongolian province of Ömnögovi. This geological formation is estimated to date back to the Campanian stage (between 75 million and 71 million years ago) of the Late Cretaceous epoch. The abundant sediments— sands, sandstones, or caliche —of the Djadochta Formation were deposited by eolian (wind) processes in arid settings with fields of sand dunes and only intermittent streams, as indicated by very sparse fluvial (river-deposited) sedimentation, under a semi-arid climate.

The Djadochta Formation is separated into a lower Bayn Dzak Member and upper Turgrugyin Member. V. mongoliensis is known from both members, represented by numerous specimens. The Bayn Dzak Member (mainly Bayn Dzak locality) has yielded the oviraptorid Oviraptor; ankylosaurid Pinacosaurus grangeri; protoceratopsid Protoceratops andrewsi; and troodontid Saurornithoides. The younger Turgrugyin Member (mainly Tugriken Shireh locality) has produced the bird Elsornis; dromaeosaurid Mahakala: ornithomimid Aepyornithomimus; and protoceratopsid Protoceratops andrewsi.

V. mongoliensis has been found at many of the most famous and prolific Djadochta localities. The type specimen was discovered at the Flaming Cliffs site (sublocality of the larger Bayn Dzak locality/region), while the "Fighting Dinosaurs" were found at the Tugrik Shire locality (also known as Tugrugeen Shireh and many other spellings). The latter is notorious for its exceptional in situ fossil preservation. Based on deposits (such as structureless sandstones), it has been concluded that a large number of specimens were buried alive during powerful sand-bearing events, common to these paleoenvironments.
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