No description available.

No description available.

<p> A detailed study of sponge boring morphotypes within the molluscan fauna of Upper Cretaceous estuarine sediments near Drumheller, Alberta provides information relevant to the depositional environment. Problems with regard to utilizing Entobia as a paleoenvironmental indicator and as an indicator of salinity do not appear to be insurmountable.</p> <p> Distributions and characteristics of associated marine organisms (phoronid worms, gastropods and encrusting bryozoa) suggest that sponge colonies were affected by salinity and sedimentation. Boring networks in Ostrea glabra suggest that more than one species of sponge were present. Sponge distribution patterns, changes in papilla and chamber sizes and preferential occurrence of sponge borings on certain shell thicknesses provide good evidence for responses to salinity and sedimentation.</p> / Thesis / Bachelor of Science (BSc)

No description available.

The salt flats of west Texas are large ephemeral lakes, Pleistocene to Holocene in age. The evaporite material in these lakes represents the sedimentary history of the lake and the surrounding area. Recently, a fossil assemblage was found in the sediments of this deposit. This assemblage includes four species of ostracoda (Limnocvthere staplini, Candona rawsoni, Candona thomasi, and Cvprideis salbrosa), two species of gastropoda, (Amnicola decepta, and Amnicola pilsbrvi), and discovery is significant because this assemblage has not been previously reported, and it provides an opportunity to reconstruct part of the physical and chemical environment of the salt flats during a portion of its history. Autecological comparison of these species indicate that they lived in a shallow, alkaline, brackish water environment. The known paleoclimate of the area, and the sedimentology support this interpretation. / Department of Geology

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1982. / Microfiche copy available in Archives and Science / Bibliography: leaves 68-69. / by Wafik Bulind Beydoun. / M.S.

In the present paper, an attempt is made to obtain the potential distribution in the case of two such charges, a source-sink combination, located on the axis of a bore hole drilled through an infinite, homogeneous medium.

Mémoire (M.Sc.A.) -- Université du Québec à Chicoutimi, 1987. / Document électronique également accessible en format PDF. CaQCU

<p> Macro-borings and other biogenic structures found in Ostrea glabra valves were examined using a dissecting microscope, SEM and X-radiography. Shells were collected from in situ and transported oyster beds of the Bearpaw-Horseshoe Canyon Formation transition (Upper Cretaceous) at Drumheller, Alberta. Emended diagnoses for Entobia, Talpina and Zapfella were proposed and systematic descriptions of these ichnogenera along with Oichnus were done. Repair blisters and partitions apparently formed by the oyster in response to irritations were also described and interpreted. It was confirmed that statistical analysis could differentiate between round holes drilled by naticids and muricids. It was possible to define fossil micro-environments on the basis of an interpretation of taphonomy and paleoecology considered within the sedimentary context.</p> / Thesis / Bachelor of Science (BSc)

M.Sc. (Geology) / Three anomalous borehole core sequences from the north eastern Karoo Basin are examined. The boreholes are located up to 30 km from each other and are lithostratigraphically completely atypical for the Vryheid Formation, Ecca Group, Karoo Supergroup. The lithologies of the three boreholes are intensely brecciated for the most part, while all of the surrounding boreholes reveal normal stratigraphy; their sedimentary strata are normally horizontal with no faulting present. The only known disturbances to the Vryheid Formation in the study area are the occurrence of intrusive mafic dolerite sills and dykes, which are known to have been contemporaneous with and immediately following the eruption of the Drakensburg Group basaltic lavas. The borehole core lithologies are described in detail with reference to their textural, mineralogical and petrographic characteristics. Mineral and bulk rock chemical data are presented. Several modes of origin of the brecciated core sequences are considered, with the primary hypothesis that the brecciation is due to diatreme activity. A review of diatremes and their mode of emplacement is proposed with reference to their occurrence within the Karoo Igneous Province, as some diatremes in the Karoo are associated with dolerite sill emplacement. The isolated occurrences, lithologies, petrography, alteration and geochemistry of the sequences are used to argue that the Vryheid Formation, intersected in the form of the three anomalous boreholes, was disturbed by diatreme activity, which are genetically related to the late dolerite sill emplacement into the Karoo Supergroup rocks.