Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 119-122).

Thesis (M.S.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.

After the establishment of the N-S Andib-Ganamub trough, the ubiquitous Lower Nosib subarkose was succeeded in the west by the Upper Nosib greywacke which indicates that orthogeosynclinal subsidence was already active in pre-Damara times. A pulse of NNE folding (F₁N) concluded this sedinentary cycle and was accompanied by amphibolite-grade metamorphism (M₁), occasional migmatisation (A₁), and later feldspar blastesis. This episode was most intense in the west, so that the overlying Damara rocks paraconformable in the east, are unconformable there. Martin's (1965) separation of the succeeding Damara basin into a western eugeosyncline and an eastern miogeosyncline applies very well to this area, though the separating hinge-line appears to have been located farther to the west (±80 Km) of the Kamanjab inlier, along the western flank of a N-S geanticlinal belt. The Lower Bakos semipelite and lenticular carbonate, thinning out against the eastern flank of this positive element controlling the deposition, may, prior to deformation, have created a transition between the western eugeosynclinal greywacke and the eastern miogeosynclinal Lower Otari carbonates. The fractured hinge-zone provided channels for the ascent of syndepositional intrusions and volcanics. Regional erosion following upwarping in the east caused a large influx of detritus into the Khomas furrow prior to the disconformable deposition of the Tillite Substage, which is the only reliable chronostratigraphic link between the base of the Upper Otavi and that of the Upper Bakos Series, the latter partially intertongueing with the succeeding Khomas Series. Gravitational creeping of the miogeosynclinal carbonates down the western slope of the upwarped Kamanjab inlier towards the sinking basin, produced the first folding (F₂O) in the east. Almost contemporaneously, buoyant uplifting forces, related to anatexis (A₂) along the axis of the eugeosyncline, created slopes sufficient to convey nappes (F₂S) of scarcely metamorphosed Damara schists towards the eastern foreland, overriding the miogeosyncline along the N-S Sesfontein Thrust. Eastern foredeeps were rapidly filled by the Mulden molasse. Steep slip folding (F₂S and F₄) in the cores and roots, and the formation of scattered domes at depth, controlled the successive structural evolution of the nappes. Large-scale axial undulations were later produced by orthogonally superposed F₃ folds striking east. The Damaran metamorphism (M₂ ), which outlasted deformation, has a Barrovian character and grades in the Damara sediments from amphibolite (sillimanite) grade in the west to greenschist (sericite- chlorite) grade in the east. In the previously dehydrated, deformed and metamorphosed, polymetamorphic (M₁/M₂ ) Nosib terrains, retrograde parageneses and transition granulites developed to the east and to the west of the Damaran hornblende-oligoclase isograd respectively. The Damaran tectono-thermal episode culminated in advanced migmatisation of the Khomas greywacke (possibly equivalent to the Salem granite-gneiss) and final anatexis (A₂ ) in the late-kinematic Ganias -Uhima (possibly equivalent to the Donkerhoek) granite, followed by widespread feldspar blastesis. The drop in rheomorphism in the deformed mass at the margin of the migmatite zone induced intense shearing and produced belts of mylonite and cataclastic gneiss. At a later stage, the Sesfontein Thrust was buffered against the Otavi dolomite relief and its speed of advancement reduced to match that of the erosion of its frontal toe, which now separates two completely different structural-stratigraphic domains: i) an eastern miogeosynclinal, feebly metamorphosed and volcanic-free domain (Damara System, Outjo Facies) deformed into non-basement-involving tectonites, overridden by ii) a western domain of suprastructural nappes and metamorphosed eugeosynclinal sediments (Damara System, Swakop Facies) deformed in response to basementinvolving tectonic processes promoted by deeply seated anatexis along the axis of the former eugeosyncline. The present model involves many stratigraphic revisions, one of the most important being that no rocks older than the Nosib Formation outcrop in the area and possibly along most of the Damara mobile belt in the western Kaokoveld.

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 thesis details the results of an integrated study of carbonate platform sedimentology, geometry, evolution and diagenesis within a sequence stratigraphic framework. This study has been based on the Upper Cretaceous carbonates within the Tremp basin of the Spanish Pyrenees, which, through the effects of minor tectonic deformation during the later parts of the Pyrenean orogeny, are exceptionally well exposed and can be studied in the form of a platform to basin cross-section upon a scale that is comparable to that of a seismic section. This study concentrates on the mid-Turonian to Coniacian-aged Congest platform and its associated basinal succession, whose sedimentology and geometrical features, in particular cyclic progradational cycles, and evidence of repeated flooding and exposure of the platform-top are interpreted in terms of . fluctuations in relative sea-level and associated variations in available accommodation space. These interpretations, together with evidence of subaerial exposure in the form of karst features, intensive dissolution and the presence of speleo-cements, are used to propose a dynamic 'forced regression' model for the evolution of the Congost platform, which involves two phases of platform development, separated by a period of forced regression. The primary and secondary porosity afforded by the abundant bi-mineralic rudists within the platform-top sediments allows for a detailed and comprehensive diagenetic study of these carbonates, in the form of a case study for a number of interesting diagenetic features. In addition to standard petrography, cathodoluminescence and stable isotope studies have been employed and have allowed the identification of such features as botryoidal calcitic marine cements, neomorphism which occurred in lagoonal waters and speleo-cements. This study also provides a detailed investigation of the diagenesis associated with subaerial exposure and the development of sequence boundaries. Differences in the early diagenesis of these carbonates from different parts of the Congost platform suggest that two separate phases of platform development experienced: 1) differing pore-fluid regimes; 2) differing frequencies and duration of subaerial exposure events; and 3) different magnitudes of relative sea-level fall. These features are considered in terms of variations in accommodation space during platform development and are used to develop the dynamic 'forced regression' model for the evolution of the Congost platform. A succession of Cenomanian to Santonian-aged basinal and slope sediments which can be correlated with the contemporaneous Santa Fe, Congost and Sant Comeli platforms and contain a large amount of allochthonous debris, much of which is derived from underiying units, are described and interpreted in terms of local tectonic activity and relative sea-level change. The final part of this thesis presents a new sequence stratigraphic model for the mid-Turonian to Coniacian-aged Congost platform which is compatible with the observations and conclusions of this study. This new sequence stratigraphic model suggests that the Congost platform developed within two separate depositional sequences, albeit with one being on a much larger scale than the other. Sequence boundaries are characterised by subaerial exposure on the platform top which can be correlated with hardgrounds and/or glauconite accumulations within the more basinal locations, overlain by deeper-water facies. The presence of submarine onlap surfaces and down-slope slide deposits immediately above the sequence boundaries suggests that the major transgressive events which followed sequence boundary development were brought about by local extensional tectonic activity, while the stratigraphic cyclicity within the sequences and major falls in sea-level which produced the sequence boundaries are interpreted to have resulted largely from eustatic processes.

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.