Geology of the southern Alberta Plains

Russell, L S; Landes, Ruth

doi:10.4095/101619

Cited by 33 publications

(31 citation statements)

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“…The fossils described in this paper were collected at localities in the Belly River Group, a unit of paralic to terrestrial rocks represented by an extensive zone of outcrop in southern Alberta (Russell and Landes 1940;Eberth and Hamblin 1993;Hamblin 1995;Eberth 2005). The group consists of three formations: the basal Foremost Formation is paralic to non-marine, whereas the overlying Oldman and Dinosaur Park formations are primarily fluvial; the group is capped by the marine Bearpaw Formation.…”

Section: Geological Setting and Localitiesmentioning

confidence: 99%

Review of Stagodontidae (Mammalia, Marsupialia) from the Judithian (Late Cretaceous) Belly River Group of southeastern Alberta, Canada

Scott

Fox

2015

Can. J. Earth Sci.

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Although stagodontid marsupials are among the most distinctive mammals of Late Cretaceous age in North America, there remain significant gaps in knowledge of their dental anatomy, particularly that of the stratigraphically oldest genus, Eodelphis Matthew, 1916. We report here on stagodontid specimens from the Judithian Belly River Group of southeastern Alberta, Canada, that document what was until now previously unknown parts of the upper and lower premolar dentition of Eodelphis browni Matthew, 1916 and Eodelphis cutleri (Smith Woodward, 1916). The new information further confirms the distinctiveness of both nominal species of Eodelphis, and bolsters previous hypotheses suggesting a close phylogenetic relationship between E. cutleri and the advanced stagodontid Didelphodon Marsh, 1889. Although the new specimens from Alberta suggest that the problematic holotype of "Boreodon matutinus" Lambe, 1902 is an upper third premolar, a referral to Eodelphis cannot be made with confidence and the name should continue to be treated as a nomen dubium. Lastly, we report the first occurrence of Didelphodon in strata of the Belly River Group, extending the geological age of the genus into the Judithian, co-eval with species of Eodelphis, and suggesting a significant prior and as yet undiscovered evolutionary history.Résumé : Si les marsupiaux stagodontidés figurent parmi les mammifères les plus distinctifs du Crétacé tardif en Amérique du Nord, d'importantes lacunes persistent dans les connaissances sur leur anatomie dentaire, en particulier celle du plus vieux genre, d'un point de vue stratigraphique, Eodelphis Matthew, 1916. Nous rendons compte de spécimens de stagodontidés du Groupe de Belly River du Judithien du sud-est de l'Alberta (Canada), qui documentent des parties jusqu'ici inconnues de la dentition prémolaire supérieure et inférieure d'Eodelphis browni Matthew, 1916 et d'Eodelphis cutleri (Smith Woodward, 1916. Les nouvelles données confirment le caractère distinctif des deux espèces nominales d'Eodelphis et appuient des hypothèses antéri-eures qui postulent un lien phylogénétique étroit entre E. cutleri et le stagodontidé avancé Didelphodon Marsh, 1889. Bien que les nouveaux spécimens de l'Alberta indiquent que l'holotype problématique de "Boreodon matutinus" Lambe, 1902 est une troisième prémolaire supérieure, il n'est pas possible de l'affecter avec confiance à Eodelphis et le nom devrait continuer d'être traité comme un nomen dubium. Enfin, nous signalons la première découverte de Didelphodon dans des strates du Groupe de Belly River, ce qui étend l'âge géologique du genre au Judithien, donc contemporain des espèces d'Eodelphis, et indiquerait une importante évolution préalable non découverte à ce jour. [Traduit par le Rédaction]

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Section: Geological Setting and Localitiesmentioning

confidence: 99%

Review of Stagodontidae (Mammalia, Marsupialia) from the Judithian (Late Cretaceous) Belly River Group of southeastern Alberta, Canada

Scott

Fox

2015

Can. J. Earth Sci.

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“…The gravel is locally cemented with secondary calcium carbonate. This formation is assigned an Oligocene age (Russell and Landes 1940), and is considered to be a fluvial deposit. Reworking of this gravel during the Pliocene (Vonhof 1965) resulted in the development of a discontinuous gravel cover on the southern flank of the plateau.…”

Section: Bedrock Geologymentioning

confidence: 99%

Loess in the Cypress Hills, Alberta, Canada

Catto¹

1983

Can. J. Earth Sci.

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Loess deposits in the Cypress Hills were derived from a single, local source located adjacent to the southwestern margin of the plateau. The distributions of sand, clay, and heavy minerals, the changes in thickness of the deposits, and the orientation of the clasts all indicate that the direction of transport was from southwest to northeast. The changes in the textural composition of the loess are reflected in variations in the sorting, with the best sorted material being located in intermediate positions. The loess is depleted in feldspar relative to the source sediments. This depletion is due to the combined effects of weathering of the feldspar to hydrous mica clays and aeolian sorting. The platy clay mineral grains would be less likely to be incorporated into the aeolian load than the spherical and bladed angular quartz grains, and the partially weathered feldspar grains would be similarly preferentially winnowed. The variations noted indicate that loess deposits formed from a single local source will not have uniform textural characteristics, but will vary in texture, sorting, and mineralogy. Similar variations would be expected in continent-wide loess sheets, although the effects of each local source would be masked by the long-distance transport component of the sediment.Les dkpBts de loess dans les collines Cypress furent alimentks par une source locale, unique et adjacente i la bordure sud-ouest du plateau. Les distributions du sable, de l'argile et des rninkraux lourds, les variations en kpaisseur des accumulations skdimentaires et l'orientation des fragments de roche, indiquent tous que le transport s'effectuait du sud-ouest vers le nord-est.Les changements de la texture des matkriaux composant le loess sont exprimks par les variations dans le triage avec les matkriaux les mieux triks occupant les niveaux intermkdiaires. Le loess est appauvri en feldspath par rapport aux skdiments de la source. Cet appauvrissement rksulte des effets combinks de la mCtkorisation du feldspath produisant des argiles a micas hydratCs et du triage kolien. La probabilitk de retrouver dans la charge Colienne des grains en plaquettes de minCraux argileux est moindre que celle des grains de quartz anguleux sphkriques et lamellaires, et les grains de feldspath partiellement altkrks subiraient une skparation prkfkrentielle analogue. Les changements observts rCvklent que les dkp6ts de loess dkrivant d'une source locale unique ne prksenteront pas de traits structuraux uniformes, mais varieront en texture, en triage et en composition minkralogique. On s'attendrait ?I des variations semblables pour des couches de loess rkpandues B la largeur du continent, bien que les traits laissks par chaque source locale seraient dissimulks par l'action du transport des skdiments sur une longue distance.

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“…Exploration in the region continued with the boundary surveys of Dawson (1875) and regional studies by Dawson (1883) and McConnell (1885). Subsequently, a large number of other geological studies based mainly on outcrops have been carried out in the area, including the following selected ones: Dowling (1917), Dyer (1927), , Williams and Dyer (1930), Fraser et al (1935), Russell and Landes (1940), Russell (1948Russell ( , 1953aRussell ( , 1953b, Furnival (1942Furnival ( , 1946, Crockford (1951), Kupsch (1956Kupsch ( , 1957, Zell (1965) and papers therein, Irish (1967), Byers (1969), Forester et al (1977), Lerbekmo (1985), Cheel (1989, 1990), Braman and Sweet (1990), and Catuneanu et al (1995). These studies have set out the basic lithostratigraphic framework for the area that is illustrated in Fig.…”

Section: Study Materialsmentioning

confidence: 99%