Physical Sciences and Mathematics Commons^™

Metamorphism And Migmatization Of Metasediments In The Precambrian English River Subprovince, Western Ontario, Rodney M. Baumann

Theses and Dissertations

Metasediments of the Precambrian English River subprovince, a subdivision of the Superior province, are conspicuously migmatized by 'bands of light-colored, igneous-appearing material. The metasediments them.selves consist of alternating layers of pelite and wacke lithologies, which represent original mudstones and graywackes respectively. Their deposition is thought to represent subaqueous turbidity flows.

For the metasediments of the study area, a 250 square kilometer portion of the English River subprovince, metamorphic grade increases southward from the English River subprovince's northern border. Two isograds have been mapped: the disappearance of muscovite and the disappearance of stable sillimanite. Geothermometry studies are consistent with the trend …

Middle And Late Wisconsinan (Pleistocene) Insect Assemblages From Illinois, Kristine D. Carter

Theses and Dissertations

Two highly organic sediment sequences from central and western Illinois (the Athens North Quarry and Biggsville sites, respectively) of Middle and Late Wisconsinan age were studied to gain knowledge about the environment and climate of this area during the time immediately prior to the maximum extent of the last glaciation. Paleoenvironmental and paleoclimatic inferences are based principally upon knowledge of the habitat preferences and geographic distributions of extant species of beetles that are represented as fossils. These data are supplemented by information from sedimentological and taphonomic studies and from previously published palynological and plant-macrofossil studies.

The Athens North Quarry site …

Petrology Of The Beulah-Zap Lignite Bed, Sentinel Butte Formation (Paleocene), Mercer County, North Dakota, David R. Kleesattel

Theses and Dissertations

The Beulah-Zap lignite bed is one of several economically important lignites in the Sentinel Butte Formation (Paleocene). This lignite occurs as a subsurface unit in the Knife River Basin of Mercer and I Oliver counties of North Dakota. The Beulah-Zap lignite is a heterogeneous carbonaceous rock unit composed of megascopic and microscopic I components, which are lithotypes and macerals, respectively. Relationships between the maceral contents of the lithotypes follow patterns similar to those of bituminous coals. Coal petrology, the study of maceral and lithotype occurrence and I distribution, was applied to determine: 1) mode of coalification, and 2) depositional environment …

Depositional Environments And Diagenesis Of Carbonates And Associated Evaporites, Frobisher-Alida Interval, Madison Group (Mississippian), Williston Basin, Northwestern North Dakota, Thomas J. Obelenus

Theses and Dissertations

The Frobisher-Alida interval is a subsurface, marker-defined unit, one of several units designated for rocks of the Madison Group (Mississippian) in the Williston Basin of North Dakota. The Frobisher Alida conformably overlies the Tilston interval and is conformably overlain by the Ratcliffe interval. 1t attains a maximum thickness of a little over 400 feet (123 m) and thins to an erosional edge along the eastern margin of the Basin.

The Frobisher-Alida is composed of limestones, dolomitic limestones, and dolostones of the Mission Canyon Formation and anhydrites of the overlying Charles Formation which exist in a complex facies relationship within the …

Late Quaternary Environmental And Climatic History Of The Southern Chilean Lake Region Interpreted From Coleopteran (Beetle) Assemblages, John W. Hoganson

Theses and Dissertations

A diverse Coleoptera fauna of 462 species in 48 families was collected from 41 locations in the Parque Nacional de Puyehue and adjacent parts of the Lake Region of southern Chile. The sample locations ranged from rain forest habitats at sea-level to Andean tundra habitats at 1500 m msl. Cluster analysis of a Dice similarity coefficient matrix revealed a broad pattern of bioassociations within the large data base, Boundaries between the bioassociations correspond largely with those of the major vegetation zones implying that the distribution of the fauna is strongly influenced by the distribution of plants. Evidence from fossils indicates …

Petrology Of The Sentinel Butte Formation (Paleocene), North Dakota, Nels F. Forsman

Theses and Dissertations

Sedimentary materials of the Sentinel Butte Formation have been petrographically examined using optical and scanning electron micro scope/microprobe techniques. The formation consists of fine-grained materials which generally are classified mineralogically as volcanic litharenites or feldspathic litharenites. Most rock units in the formation are siltstones and mudstones. Multiple source rock types, including volcanic, metamorphic, and sedimentary, are represented by mineralogic constituents, but volcanic rock fragments are most abundant. Petrographic distinctions between basal and uppermost sandstone units suggest that a change in sediment supply took place near the end of Sentinel Butte time. Authigenic cement development appears concentrated in more porous and …

Provenance Study Of Late Eocene Arkosic Sandstones In Southwest And Central Washington, Mark Edward Byrnes

Dissertations and Theses

The purpose of this study is to compare the sandstone composition and trace element geochemistry between samples representing the Summit Creek sandstone, Naches, Chumstick, and Carbonado Formations in order to determine if these sediments were all derived from the same provenance, and to determine the composition of the source rocks in hopes to identify the present day location of the source areas.

Geochemistry And Petrology Of The Lake Vermilion Formation, Ely Greenstone Belt, Northeastern Minnesota, Scott E. Robinson

Theses and Dissertations

Alteration in the Lake Vermilion Formation took place at low water/rock ratios. Calculations using the method of Grescens (1967) indicate that the amount of open-system elemental exchange was slight. During secondary alteration, Ca, Na, K, Rb, Sr, and Ba were very mobile; Mg and Fe were less mobile; Si, Al, Ti, Zr, Y, and Ni were slightly mobile. Chemically the rocks resemble modern spilites and keratophyres.

The dacites and basalts are depleted in Ti, Zr, and Y relative to Tertiary igneous rocks of similar composition. The Lake Vermilion Formation basalts display a volcanic arc basalt trend of constant Ti02 with …