<p> The Sapeomithidae are a unique and poorly understood clade of Early Cretaceous birds from the Jehol Group of Liaoning Province, China. Four species of sapeomithids are known: <i>Sapeornis chaoyangensis, Didactylornis jii, Sapeornis angus tis</i>, and <i>Shenshiornis primita</i>. <i>Omnivoropteryx sinousaorum</i> is allied with sapeomithids, although its nomenclature remains a source of contention. The validity of these taxa is challenged via an in-depth anatomical revision and morphometric analyses involving 18 specimens of sapeomithids, including the aforementioned holotypes. The results reveal that the only anatomical difference separating each species is size, implying a growth series trend among the specimens. This provides clear evidence that these species are junior synonyms of <i>Sapeornis chaoyangensis</i>. In addition, critical anatomical descriptions previously unknown for these specimens expand our knowledge of this clade, paving the way for future anatomical and phylogenetic studies of this enigmatic avian taxon.</p>

North of Grand Rapids, Manitoba, new exposures of a carbonate succession prompted study of the lithology and paleontology of the uppermost Ordovician along the northern edge of the Williston Basin in Manitoba. Modern concepts and approaches were applied in examining the sedimentary rocks and fossils, including X-ray diffraction, stable carbon and oxygen isotope analysis, and statistical algorithms. Nine lithofacies, representing a series of shallowing events, and environmentally significant subaerial exposure surfaces, were identified. The distribution and relative abundance of identified fossils were used to delineate faunal associations, which were examined in the context of the impending end-Ordovician mass extinction. Historically, the stratigraphy of the latest Ordovician has been problematic. Therefore, detailed examination of this succession aided in clarifying unit boundaries in the Stony Mountain and Stonewall formations. Study of this new succession contributed a wealth of information to the understanding of the uppermost Ordovician of Manitoba.

The Jurassic litho-biostratigraphy is reviewed and Jurassic depositional models are defined in order to clarify some regional stratigraphic uncertainties and to evaluate the hydrocarbon potential of the Jurassic of the United Arab Emirates (UAE). A thick succession of Triassic-Cretaceous shallow-marine carbonates is exposed in Wadi Naqab, southeast of Ras Al Khaimah in the UAE, Musandam Peninsula. The Jurassic, 1310 m thick, is examined using biostratigraphy, sedimentology and sequence stratigraphy and compared with the Abu Dhabi subsurface. Direct composition of the Jurassic foraminiferal biozones and algal assemblages can be made between Wadi Naqab and the South-Tethyan realm. Palynological data from the subsurface demonstrate that much of the Liassic, which is well represented in the Musandam Peninsula, is missing over most of the Emirates. A ca. 50 Ma time gap was defined within the Abu Dhabi clastic Minjur Formation (previously assigned to the Triassic). The age of the palynoflora of the upper Minjur is Bajocian, while the lower Minjur yielded Late Carnian palynomorphs. The Upper Toarcian and most of the Aalenian is also probably missing in the Musandam Peninsula, as in the subsurface of the Emirates and Saudi Arabia. A new Bajocian foraminifera <I>Pseudodictyopsella jurassica</I>, n. gen., n. sp., was recognised, and the inception of some stromatoporoids was earlier than previously thought. The Liassic of Wadi Naqab is dominantly a metre-scale 5^th-order Milankovitch-driven succession composed of peritidal cycles. Cycle tops are commonly marked by corrosion zones and/or karsts. Stacked paleokarsts are found particularly in the Sinemurian and Lower Pliensbachian. In Wadi Naqab, the Middle and Upper Jurassic seem to comprise one shallowing-upward 3^rd-order cycle built of abundant 5^th-order cycles. As a result of comparisons in this study, the Bajocian Izhara Formation is redefined and a new type-section proposed. Most of the Kimmeridgian and Tithonian are absent in Wadi Naqab, and eastern onshore and offshore Abu Dhabi, as the result of uplift and erosion before deposition of the Lower Cretaceous. Possible major Jurassic (Liassic-Early Kimmeridgian) hydrocarbon plays of Abu Dhabi are: the Marrat lowstand wedge of eastern onshore, the Jurassic onlap of Triassic high blocks in offshore areas, the Minjur lowstand clastics, the offshore Uweinat and Upper Araej and the Upper Jurassic Hadriya and Hanifa reservoirs.

<p> The current biodiversity crisis is challenging the ability of conservation biologists to both monitor ongoing declines and create effective management plans. Ongoing habitat destruction, pollution, introduction of invasive species, and the initial stages of climate change are only some of the anthropogenic stresses that face today's biosphere. On human time scales, these changes are unprecedented, curtailing the availability of knowledge regarding ecological responses to stress and disturbance. The fossil record provides numerous disturbances of varying magnitudes throughout the history of life, and yet this resource has been often overlooked or dismissed by biologists. The purpose of this study is to examine the effects of stress on communities using methods that allow integration of modern and fossil data. With this goal in mind, various levels of disturbance are investigated across increasing temporal and spatial scales.</p><p> At the smallest spatial and temporal scale, I examined the effect of recent lake acidification on plankton communities, using techniques commonly applied by ecologists, as well as introducing a new method based on a well-established technique. Throughout this thesis, I use the Buzas-Gibson evenness metric and Non-metric Multi-Dimensional Scaling analysis (an ordination technique), as well as applying Rank-Abundance Curve Kurtosis, which measures the shape of species-abundance distributions. Each of these techniques is a different way of representing community structure, with each metric providing slightly different information. Within the lake acidification system, all communities displayed a shift in community structure as pH dropped, and again when pH values returned to neutral, indicating a gradual recovery from acid stress. The timing of this change reveals the ability of different communities to resist acidification, and the resilience of those communities through the recovery phase.</p><p> To determine the feasibility of comparing modern and fossil data, I selected four unrelated datasets with distinct disturbance events to represent different time scales, from two decades to one million years. Each dataset displayed a similar pattern; the disturbance event created a distinct shift in community structure followed by a gradual recovery after the stress levels decreased. A major concern when comparing modern and fossil data is the difference in temporal resolution, and specifically the effect of time-averaging which is expected to obscure ecological signals. Instead, I found that applying a model of time-averaging across the community data reduced background noise, thereby clarifying the pattern of ecological change observed in the raw data.</p><p> Extending the temporal and spatial scale, I explored the ecological response of marine microfossil assemblages during three intervals of rapid global warming, as analogues for modern global warming. Four taxonomic groups were included, two benthic and two planktic. Overall, diversity within communities increased during global warming, however this was due to the response of the planktic groups, as both benthic groups showed decreases in diversity. These findings support the utility of the fossil record in examining past disturbances, by providing a useful prediction for biotic responses to global warming.</p><p> Representing the largest spatial and temporal scale is the Botomian mass extinction (mid-Early Cambrian). This mass extinction is the first recognized mass extinction in the history of life, and occurred during an interval of rapid evolution and faunal turnover. During the extinction interval, there was a distinct change in community structure and an associated increase in instability.</p><p> The findings of this study are unique; community structure displays a similar response to stress across various taxonomic groups, in different environments, and at multiple temporal scales. The commonality in community response to stress likely represents a fundamental feature of disturbed ecosystems. Not only is the comparison of modern and fossil data possible, such comparisons offer new discoveries relevant to conservation biology and about the very nature of life on Earth.</p>

The Fairholme Carbonate Complex is the southernmost and largest in an extensive stromatoporoid-dominated reef domain that developed in Alberta during Frasnian time. Its western margin is defined, and exhibits a major re-entrant 25 km wide named the Shark Embayment. A Devonian paleoclimatic model suggests that the western margin was subjected to seasonal oceanic upwelling of nutrient-rich and oxygen-poor waters that influenced the development of the carbonate buildups. / Lithostratigraphic units of the Fairholme Group are characterized in terms of a Rocky Mountain (RM) Conodont Zonation. In the western part of the study area, the Flume carbonate platform began to onlap the westernmost slope of the West Alberta Ridge (WAR) as early as latest Givetian time (norrisi Zone). To the east, the Flume platform did not onlap and begin to cover the crest of the WAR until the succeeding RM Zone 1. The overlying Upper Cairn Member (containing a unique coral biofacies) and Perdrix Formation range from the uppermost RM Zone 1 to Zone 4b. The Peechee Member is difficult to date, but is probably within Zones 5a to 5b; the overlying Grotto Member is no younger than Zone 5b. The Arcs Member is within Faunal Intervals (F.I.) 6-7, and the Ronde Member is within Faunal Interval 8 which includes the Frasnian-Famennian boundary near its top. The Mount Hawk ranges from Zone 4b/5a to F.I. 8. / Stromatoporoids were widespread and abundant calcareous benthos living in shallow, tropical, oligotrophic, and agitated marine environments. Thirty-two species representing 5 different orders of stromatoporoids are recognized in this study; thirty-one species comprise a diverse fauna in the Cairn Formation. Five stromatoporoid assemblages are defined in the Flume and Upper Cairn succession, and are correlated with RM conodont zones. Stromatoporoids exhibit mostly domical, but also bulbous, laminar, and dendroid growth forms that were genetically prescribed and only slightly modified by environmental factors. Trace element geochemistry of Devonian stromatoporoids indicates that these sponges originally secreted a calcitic skeleton, in contrast to Ordovician stromatoporoids which secreted an aragonitic skeleton. Evidence suggest that Paleozoic stromatoporoids eventually developed into mixotrophic organisms enabling them to construct large carbonate buildups, but they were also vulnerable to the devastating effects of paleoceanic upwelling of nutrient-rich waters.

Typescript (photocopy) / Includes bibliographical references / 2 v. : 63 plates, ill. (3 fold.) map ; 30 cm. + 2 fold. maps in end pocket / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology, 1980

The structure and petrology of Upper Precambrian and Cambrian rocks have been studied in detail, in an area 38 miles north - east of Adelaide, South Australia. The rocks occur within a broad zone of high grade metamorphism on the eastern side of the Mt. Lofty Ranges. The Upper Precambrian succession consists predominantly of pelitic and semi - pelitic schists, quartzites, calc - silicate rocks and calc - schists, and the Cambrian sequence of quartzo - feldspathic schists, migmatites, granite gneiss, calc - silicate rocks and minor pelitic schists and quartzites. The rocks have reached the sillimanite grade of metamorphism and the metamorphism is of the low pressure - intermediate type. Dolerites, pegmatites, minor granodiorites and granites intrude the meta - sediments. Mineralogical and structural relationships of the granite gneiss, indicate that it has been formed by recrystalliaation of the quartzo - feldspathic schists. Small scale metamorphic differentiation, appears to have accompanied the recrystallization. The migmatites are believed to have been formed by metamorphic differentiation rather than by anatexis. Three phases of deformation are recognised in the Upper Precambrian rocks and two in the Cambrian. The second deformation recorded in the Upper Precambrian rocks does not appear in the Cambrian rocks. Each deformation has been accompanied by the formation of foliation. In the Proterozoic rocks deformed by the second and third phases of folding, the foliation is a crenulation cleavage. The deformations in both the Upper Proterozoic and Cambrian sequences are considered to be related. Petrofabric studies of quartz, scapolite and biotite are related to the respective macroscopic structures. An analysis of the chronology of crystallisation and deformation of these rocks indicates that crystallisation continued during and after each phase of deformation. Faulting commenced either prior to or during meta - morphism. Intense metasomatic activity followed a later phase of faulting resulting in the widespread development of albitites and in some cases talc ore bodies. The albitites formed in the fault zone were subsequently brecciated by further movement and later healed by the introduction of more metasoinatic fluid. / Thesis (Ph.D.) -- University of Adelaide, Department of Geology, 1966.

Thesis--University of Cincinnati. / Bibliography: p. 315-320. Also available in electronic format.

Thesis (Ph. D.)--Columbia University. / Includes bibliographical references (p. 58-60).

Thesis--Columbia University. / Bibliography: p. 559-562.