Assignment of Yamaceratops dorngobiensis and Associated Redbeds at Shine Us Khudag (Eastern Gobi, Dorngobi Province, Mongolia) to the Redescribed Javkhlant Formation (Upper Cretaceous)

Eberth, D. A., Kobayashi Y., Lee Y. N., Mateus O., Therrien F., Zelenitsky D. K., & Norell M. A. (2009).  Assignment of Yamaceratops dorngobiensis and Associated Redbeds at Shine Us Khudag (Eastern Gobi, Dorngobi Province, Mongolia) to the Redescribed Javkhlant Formation (Upper Cretaceous). Journal of Vertebrate Paleontology. 29, 295-302., Jan: Univ Nova Lisboa, Hokkaido Univ, Museu Lourinha, Amer Museum Nat Hist, Korean Inst Geosci & Mineral Resources, Royal Tyrell Museum, Royal Tyrell Museum, Univ Calgary





Assigning Central Asian nonmarine Cretaceous vertebrate fossils and their host rocks to lithostratigraphic units and establishing their sub-epochal ages can be challenging. Researchers frequently struggle with inconsistently applied locality and stratigraphic
names, have to consider the impact of two distinct stratigraphic philosophies (Benton 2001a; Gladenkov, 2007), and often encounter additional challenges in working with
manuscripts published in, or translated from, a variety of languages (e.g., Benton, 2001b). In addition to these challenges, chronostratigraphic data are rare due both to a lack of discovered rocks amenable to radiometric dating, and issues complicating
paleomagnetic sampling in the Cretaceous (e.g., “Cretaceous Quiet Zone,” Ogg et al., 2004). There are also inherent limitations in nonmarine biostratigraphic schemes and,
in some cases, field areas may have complex stratigraphic architectures and depositional histories that are difficult to resolve without the aid of subsurface data (e.g., Graham et al., 2001; Johnson, 2004). Thus, although there have been significant advances in our knowledge about the ages and relationships of
nonmarine Cretaceous vertebrate fossils and assemblages from southern Mongolia in the past 85 years, there remains much to learn and clarify.
During the 2007 field season, the Korea-Mongolia International Dinosaur Project (KMIDP) worked two weeks in the Eastern Gobi (Dorngobi Province, southwest of  Sainshand) at three Upper Cretaceous localities: Shine Us Khudag, Khar Khutul, and Bayn Shiree (Fig. 1). Exposures of the 280 m thick, buff-colored Baynshiree Formation/Svita at each locality produce a rich assemblage of Cenomanian-Santonian vertebrate and invertebrate fossils, including dinosaurs (Vasil’ev et al., 1959; Martinson et al., 1969; Barsbold, 1972; Sochava, 1975; Martinson, 1982; Jerzykiewicz and Russell, 1991; Hicks et al., 1999; Ishii et al., 2000; Khand et al., 2000; erzykiewicz, 2001; Shuvalov, 2001; Graham et al., 2001). However, north of Shine Us Khudag and south-southwest of Khar Khutul, a 380 m thick succession of fossiliferous alluvial redbeds (here called the Shine Us Khudag redbeds) is broadly exposed (50 km2) and
conformably overlies the Baynshiree Formation/Svita (Fig. 2). The Shine Us Khudag redbeds have variously been assigned to the Jibhalanta Suite, Javkhlant Formation, Baruungoyot Svita, Djadokhta Formation, and the “Barunbayan” (Table 1), and
since 1969 have been regarded by most stratigraphers working in the area as having a Santonian-Campanian age (Martinson et al., 1969; Jerzykiewicz and Russell, 1991; Khand et al., 2000; Jerzykiewicz 2001; Shuvalov, 2001). 
Locally abundant in the Shine Us Khudag redbeds are remains of the basal protoceratopsian dinosaur, Yamaceratops ..........