Missouri Coteau Research Articles

Life cycle of the marsh grass, Scolochloa festucacea

This paper describes the life cycle of Scolochloa festucacea, a dominant species in potholes subjected to regular burning or mowing throughout the Drift Prairie and Missouri Coteau of the Northern Great Plains. Vernal growth is initiated at extremely low temperatures; some plants grow in water at the freezing point. Flowers develop in June if the pothole is inundated in the spring. Mature caryopses drop in July, but do not germinate until the next year. Tillers and new rhizomes are produced in August, followed by senescence in late September – early October.

Late Quaternary Fossil Beetle Assemblage from the Missouri Coteau, North Dakota

A well-preserved fossil beetle assemblage of 70 taxa is described from a 10,000-yr-old sequence of lacustrine sediments on the Missouri Coteau, North Dakota. All of the 31 specifically determined taxa have been assigned to extant species, of which only 15 have been currently reported living in North Dakota. Many of the species are tree dwellers, some confined to spruce, thus indicating a woodland environment in contrast to the virtually treeless prairie of today. There is apparently no region in North America where the species comprising the fossil assemblage are living together at present. Two-thirds of the species have been reported from woodland areas of southern Manitoba. Others, however, live mainly in eastern North America; one species is found in western North America. Development of prairie about 9,000 to 8,500 yrs ago was probably responsible for the migration of the species within the fossil assemblage, although it is not clear why this should result in the widely separated distributions of many of the species at the present day.

Paleolimnology of Late Quaternary Deposits: Seibold Site, North Dakota

A unique late Quaternary lacustrine deposit has been discovered recently on the Missouri Coteau of North Dakota. A diverse, extremely well-preserved biota of more than 160 species has been recovered primarily from an organic mud deposited about 9500 years before the present. The lacustrine body shallowed gradually as the climate became drier.

BRYOPHYTE SUBFOSSILS OF A LATE-GLACIAL DEPOSIT FROM THE MISSOURI COTEAU, SASKATCHEWAN

Bryophyte and associated macro-subfossils were recovered from a kettle located in prairie southwest of Moose Jaw in the Missouri Coteau of southern Saskatchewan. The higher plants were discussed in an earlier paper.Three samples taken from the organic layer gave C14 datings ranging from 11,650 ± 150 to 10,270 ± 150 B.P.Sixteen species and one variety of Musci were recovered. Eleven of these were found in the lowermost zone at a depth of 510–450 cm. This zone was composed of bryophytes and higher plants characteristic of a modern Picea forest. Fifteen bryophyte taxa were recovered from the middle zone at a depth of 450–290 cm. The macro-subfossils in this zone are typical of a present-day Populus–Picea forest. No bryophytes were found in the upper layer, 290–280 cm characterized by higher plant macro-subfossils and pollen typical of a modern Picea forest.All bryophytes recovered belong to present-day taxa; however, many of the boreal species are not now found in the region as the southern margin of the boreal forest is now 200 miles to the north.

CONTRIBUTIONS TO THE HOLOCENE PALEOECOLOGY OF WESTCENTRAL CANADA: A LATE-GLACIAL DEPOSIT FROM THE MISSOURI COTEAU

A buried deposit of limnic sediment was excavated from a site on the Missouri Coteau of Saskatchewan, within the Mixed Prairie section of the Great Plains. Carbon-14 determinations indicate that the section is late-glacial, possibly deposited during an interstadial terminated by the Condie (= Valders?) re-advance. On the basis of the records of about 60 taxa of Tracheophyta and a pollen diagram, the section is characterized by lower, middle, and upper plant assemblages. It is suggested that the lower and upper assemblages, distinguished mainly by a Picea – Shepherdia canadensis – Salix – Artemisia pollen spectrum, indicate the prevalence on mesic sites of a spruce forest. The middle assemblage, having an array of macrofossils and a few microfossils of temperate geographical affinity and a pollen spectrum suggesting relatively less spruce and (or) more herbaceous vegetation, is interpreted in terms of a mixed spruce–poplar forest on mesic sites with shrub and grassland communities on the more xeric habitats. This tripartite division of the section in terms of ecologically concordant plant assemblages suggests an amelioration of environment followed by a deterioration which was probably correlative with the Condie re-advance.

A Comparison of a Fossil Pleistocene Molluscan Fauna from North Dakota with a Recent Molluscan Fauna from Minnesota

Geological and paleontological studies of the glacial deposits in the Missouri Coteau district in south-central North Dakota have produced collections of mollusks which lived in lakes and streams approximately 8,000 to 12,000 (radiocarbon) years before the present (late Wisconsinan Age, Pleistocene Epoch). The geology and present position of the glacial sediments suggests the presence of buried stagnant glacier ice in the sediments at the same time the molluscan fauna existed. The relatively complex species composition of the molluscan fauna suggests that these lakes were temperate and at least mesotropic. The great thicknesses of drift in the area, taken in conjunction with the fact that mollusks were able to occupy essentially superglacial lakes shortly after the emplacement of the sediments of the Missouri Coteau, further suggests that the local climate was temperate during the late part of the Wisconsinan Age during which active glaciation was still taking place in North Dakota. The fossil mollusks are compared with the molluscan fauna of a modern lake in Beltrami County, Minnesota. The differences in climate which now exist between the area of the Missouri Coteau and Beltrami County, Minnesota are suggested to be the increment of net climatic change in southern North Dakota from early Twocreekan time to present. Recent mapping of the glacial deposits of the Missouri Coteau of south-central North Dakota by the North Dakota Geological Survey and the University of North Dakota Department of Geology has shown that the present topography of the area was formed largely by stagnation of the margin of the Pleistocene (late Wisconsinan, see Fig. 1) continental glacier. Among the glacial features found in this area are numerous deposits of ice-contact lake sediments and icecontact outwash sand and gravel containing abundant invertebrate fossils. These late Wisconsinan fossils, including gastropods, pelecypods, and ostracods are modern in appearance. The fossil fauna is not compared here with the Recent molluscan fauna of the area as the mollusks of North Dakota are as yet only poorly known. However, few, if any, mussels occur in the lakes of the Coteau, and the snails are mainly pulmonates that are able to survive the fluctuations of the ephemeral lakes. The fossil fauna is typified by a wide distribution of the prosobranch genera Valvata and Amnicola. In this respect the fossil fauna more closely resembles those found in the more humid climate to the east. The fossil mollusks from south-central North Dakota therefore, will be compared with mollusks from a selected lake (Long Lake) in north-central Minnesota. Traditionally, Pleistocene time divisions have been erected on lithologic criteria which are assumed to reflect climatic conditions. Those climate conditions which caused continental glaciers to advance

Ice-Thrust Ridges in Western Canada

Numerous parallel, generally sharply crested ridges constitute a distinctive element of several portions of the Missouri Coteau, which is a prominent upland in Saskatchewan and Alberta, western Canada. The map pattern of the ridges, which in places are over 200 feet high, is linear or curvilinear with the concave side to the east, northeast, or north. Exposures reveal that the ridges are composed mainly of complexly folded and faulted unconsolidated sediments of Cretaceous age. The deformations resulted from ice push by the Wisconsinan glacier where it moved upslope against the Missouri Coteau, especially where it entered preglacial valleys and pressed against the sides of these pre-existing, transverse sags of the upland. The ridges are thus regarded as Stauchmoranen or ice-thrust ridges, which represent slices of frozen ground deformed and dislocated by the glacier but left more or less intact during the final melting of glacier and ground ice. The ice-thrust ridges, which trend parallel to the glacier ...

Lineaments in Avonlea Area, Saskatchewan

Linear features revealed by air-photo mosaics of the Avonlea area are due to topographic relief, stream adjustments, alignment of elongate closed basins, vegetation, and soil-moisture differences. They occur in two sets parallel with known faults and some appear to coincide with faults mapped at the surface. They are therefore regarded as lineaments, which are the surface expression of faults. The fault pattern, the position and great length of some faults, and the location of the epicenter of a very strong earthquake are advanced as arguments for a tectonic origin of the faulting. Minor faulting due to the removal of Middle Devonian salt by solution, may have taken place after the deposition of the salt. Large faults of tectonic origin, which appear to be responsible for the Missouri Coteau, are probably basement faults along which recurrent movement has taken place. Fault traps of hydrocarbons in pre-Middle Devonian units are possible, although the apparent displacement of older strata may not be as much as that in younger rocks.

Preglacial Missouri River in Saskatchewan

The valley of the preglacial Missouri River can be traced from North Dakota into southeastern Saskatchewan. The preglacial Missouri River was joined by the preglacial Yellowstone River at a point about 15 miles north of the international border. Downstream from the junction the preglacial Missouri River flowed north of a highland in the vicinity of Estevan before entering Manitoba, where it joined the Red River to drain into Hudson Bay. Bedrock-surface contours show that the Missouri Coteau and Moose Mountain were uplands separated by a lowland, as at present.