Maps in pockets bound with piece. / Digitized by Kansas Correctional Industries

An array of stratigraphic, chemical, isotopic, and mineralogical evidence indicates that an impact terminated the Cretaceous Period. The 180-km-diameter Chicxulub crater, which now lies buried on the Yucatan peninsula of Mexico, was probably formed by the impact. The impactor was probably a long-period comet. Shock devolatization of the thick carbonate/evaporite sequence impacted at Chicxulub probably led to a severe and long-lasting greenhouse warming and a prompt pulse of sulfuric acid rain. The fallout of crater ejecta formed two layers: a lower layer which varies in thickness following a power-law relation based on distance from the Chicxulub crater and an upper, globally-distributed, uniformly ∼3-mm-thick layer. The upper layer probably represents the fallout of condensates and entrained solid and liquid particles which were distributed globally by the impact fireball. The lower layer consists of brecciated rock and impact melt near the crater and largely altered tektites far from the crater. The clasts of this layer were probably ballistically transported. The Raton, New Mexico K/T boundary section preserves the fireball and ejecta layers in a coal-free nonmarine environment. Siderophile, chalcophile, and lithophile trace element anomalies occur similar to those found at marine K/T boundary localities. Soot occurs peaking in the 3-mm-thick fireball layer and the immediately overlying 3 mm of sediment, implying prompt burning of the Cretaceous forests. The Brazos River, Texas continental-shelf K/T sections preserve coarse boundary sediments which were probably produced by impact waves. Siderophile and chalcophile trace-element anomalies occur suggesting that the fireball layer and possibly part of the ejecta layer are interbedded with the coarse boundary sediments. The Beloc, Haiti deep-sea K/T sections preserve a thick ejecta sequence including altered and unaltered tektites and shocked minerals capped by the fireball layer. The thick K/T ejecta preserved at this and other nearby K/T localities require a source crater of Chicxulub's size and location. The composition of the tektites and shocked grains require an impact into recently extracted continental crust with a carbonate/evaporite component as found at the Chicxulub crater.

This study provides a sequence stratigraphic framework within which to consider Brigantian Yoredale strata.  The framework has been used to determine the relative effects of syn-depositional tectonics, eustasy and climate on Yoredale sequence stratigraphic architecture within the northern Britain study area.  Seventeen high-frequency depositional sequences have been identified and correlated within Brigantian strata in northern England and the Midland Valley of Scotland.  Examination of sequence thickness and lithofacies stacking patterns has allowed the spatial and temporal occurrence of syn-depositional tectonism to be constrained and the effects on sequence and lithofacies architecture defined.  The overall effect of tectonics on Yoredale sedimentation and cyclicity are interpreted to have been minimal.  The correlation of sequence boundaries between the two very different tectonic regimes of northern England and the Midland Valley of Scotland would suggest that tectonics was not the driving mechanism behind cyclicity as suggested by some workers.  Correlation of sequences with coeval sequences in the Illinois Basin of mid-continent North America demonstrates a lack of correlation to a particular tectonic regime or depositional facies type.  The close similarity of sequence architecture between the Illinois Basin and northern British basins is taken to indicate that the sequences were synchronous depositional events that resulted from high-frequency eustatic sea-level changes.  Glacio-eustasy provides the most logical explanation for the observed sequence architecture and apparent synchronous development of sequences and sequence boundaries across the northern Britain study area and globally.

No description available.

iii, 260 leaves : ill., charts & maps in back pocket / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1970) from the Dept. of Geology, University of Adelaide

Precambrian stromatolites in South Australia are almost entirely restricted to the folded rock sequence of the Adelaide Geosyncline, a large, deeply subsiding basin with predominantly shallow - water sediments. The history of research into the age and fossils of the Precambrian rocks is reviewed, and a possible time - framework is suggested on the basis of available radiometric data. Stromatolites, laminated structures formed by trapping of detritus and precipitation of chemical sediment by algae and bacteria, have been studied by other workers from at least two points of views : most Western authors regard stromatolite morphology to be purely environmentally determined, while one Russian school maintains that it is largely controlled by the algae present, and that stromatolites evolve as a consequence of the evolution of the algae forming them. They concluded this from an empirical study of widespread stromatolites of different ages, which made possible the biostratigraphic subdivision and correlation of many Late Precambrian sections. The Russian methods of study and taxonomy have now been applied to South Australian stromatolites for the first time. Of the eighteen forms of columnar stromatolites described, five are identical or nearly identical to Russian forms. Nine forms are new, but sufficiently similar to Russia forms to allow inclusion in the same groups as these. Groups and forms must be defined on the basis of numerous characters, which may be given different relative weighting for different taxa. The taxa so defined have restricted ranges in geological time. Stromatolite correlation with the Russian sequence suggests that the Early Adelaidean ( i.e. pre - tillite ) beds are middle Riphean ; the Skillogalee Dolomite is youngest middle Riphean, i.e. older than the Late Riphean Bitter Springs Formation of Central Australia. The Late Adelaidean Umberatana Group assemblage, correlated with the youngest Late Riphean, has seven groups in common with the Bitter Springs Formation, but unlike the latter, it overlies the lower tillite. A comparison with available radiometric data shouts good agreement for the Umberatana Group, but some conflict with one recent age determination exists for the Early Adelaidean. A study of the environments of growth of South Australian stromatolites shows that at least three forms, of widespread distribution, grew under a variety of conditions of energy, oxidation, type of sediment influx, and possibly salinity. The taxa defined are stable under these varying conditions, but there are minor modifications due to differences in environmental energy. Skillogalee Dolomite stromatolites grew under varying energy conditions on a very extensive and level carbonate depositing platform, frequently under hypersaline conditions. Umberatana Group stromatolites inhabited a marine environment, either in marginal littoral zones in the south - western and north - eastern Flinders Ranges, or on off - shore carbonate banks interpreted to be related to rising diapirs. In both cases, stromatolites formed during episodes of shallowing water depth. / Thesis (Ph.D.)--Department of Geology and Mineralogy, 1971.

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Micropaleontological data have been analyzed through mathematical and statistical procedures, in order to: (1) establish the distribution pattern of radiolarian assemblages in the surface sediments, (2) establish the relationship of these assemblages with oceanographic variables, (3) determine the faunal composition down-core with respect to the faunal surface pattern, and (4) estimate water temperatures and 1OO M PO₄ within the geological past. This, together with the analysis of opal and quartz content of the sediments, has permitted the inference of the paleo-oceanography of the subtropical southeastern Pacific during the last 75,000 years. Factor analysis shows that five major radiolarian assemblages (factors), accounting for 93.6% of the variance, reflect the mixed layer circulation and its associated water masses. According to their position in the area, these factors are called: (1) the Subtropical factor, (2) the Equatorial factor, (3) the Peru (current) factor, (4) the Chile (current) factor, and (5) the Backwater factor. The subtropical factor is correlated with "warm" water temperatures, the Equatorial factor with opal production, the Peru factor with coastal upwelling, the Chile factor with "cool" water temperatures, and the Backwater factor with mixing of water masses. The distribution pattern of quartz reflects the position of the southeast trade winds which largely control the oceanographic conditions of the subtropical southeastern Pacific. The opal distribution resembles the patterns of surface primary productivity. Opal content is "high" below the Equatorial Undercurrent. However, it is "low" along the South American coast probably due to dilution by terrigenous input. Cores RC11-230 (8°48'S-110°48'W), V19-29 (3°35'S-83°56'W), and Y71-6-12 (16°26'S-77°23'W) were used in the stratigraphic study. Their stratigraphic control (correlation) is made through their δ ¹⁸O records. The changes of quartz, opal and radiolarian assemblages contents down-core are considered to be the result of shifts or changes in intensity of the atmospheric and oceanic circulation. Oceanographic changes have occurred in the subtropical southeastern Pacific during the last 75,000 years, but they are not manifested at each location in the same form. These changes have not been synchronous with changes of global ice volume; rather, during pronounced climatic changes, a sequence which is initiated by changes in the wind circulation is observed. The oxygen isotope stage 4 is characterized by mixing of water masses, "deep" thermocline and low concentration of nutrients. The lower interval of isotope stage 3 is characterized by weakened wind-driven circulation and "high" water temperatures. The middle of isotope stage 3 is a time in which wind-driven conditions become dominant in the region. Oxygen isotope stage 2 is "cool" and has strong wind-driven conditions. The shift to the present oceanographic conditions in the subtropical southeastern Pacific occurred 11,000 years ago. / Graduation date: 1976

Thesis (M.S.)--Oregon State University, 1983. / Typescript (photocopy). Some col. ill. and col. maps folded in pocket. Includes bibliographical references (leaves 168-178). Also available via the World Wide Web.

Thesis (Ph. D.)--University of Chicago, 1916. / "Private edition distributed by the University of Chicago Libraries, Chicago, Illinois." "Reprinted from the Journal of geology, Vol. XXV, Nos. 2-4, 1917."