No description available.

Thesis (MSc)--University of Stellenbosch, 2006. / ENGLISH ABSTRACT: The Barremian to Albian siliciclastic deep-water deposits of the central Bredasdorp Basin were investigated primarily in terms of their stratigraphic evolution, depositional characteristics and facies distribution. Cores from the deep-water deposits reveal that the facies successions are composed of massive, ripple cross- to parallel-laminated sandstones, conglomerate, massive claystone, alternating laminated to interbedded sandstone/siltstone and claystone, laminated and clay-rich siltstone. These facies are grouped into channel-fill, sheet-lobe, overbank and basin plain deposits, by inference. The application of sequence stratigraphy, based on gamma ray and resistivity log patterns, reveals that all 3rd-order depositional sequences comprise 4thorder cycles. The latter are subdivided into three components (lowstand, transgressive and highstand systems tracts), based on vertical facies changes and internal stratigraphic key surfaces. Taking the 13Amfs as the stratigraphic datum for each well, correlation was possible on a regional basis. Lowstand deposits, comprising thick amalgamated massive sandstones, were interpreted to represent channelfills. Their vertical and horizontal stacking forms channel-fill complexes above Type 1 unconformities. Adjacent thin-bedded intervals, comprising parallel- to ripple cross-laminated sandstones, were interpreted as levee/overbank deposits, whereas clay-rich intervals were interpreted to represent basin plain deposits of hemipelagic origin. Facies associations and their distribution have revealed that channel-fills are associated with overflow deposits and sheet sand units. These deposits, as well as downdip sheet sands associated with small channel-fills within the 9A, 11A/12A, 13A Sequences and the 14A Sequence were interpreted to have been deposited in a middle fan to upper fan setting. A similar association occurs in the 10A Sequence, except that thick conglomerate units are present at the base of proximal channel-fills. This led to interpret the 10A Sequence as being deposited in a base-of-slope to upper fan setting. The thickness of each sequence, as revealed by isochore maps, shows sinuous axial flow path which corresponds to channel-fill conduit. The continuous decrease of this sinuosity upward in the succession was interpreted as being related to basin floor control along the main sand fairways. Successive flows result in erosion-fill-spill processes, which locally favour connectivity of reservoirs over large areas. Recognition of higher-order sequences and key stratigraphic surfaces helps to understand internal stratigraphic relationships and reveals a complex and dynamic depositional history for 3rd-order sequences. However, sparse well control and uneven distribution of boreholes, as well as lack of seismic and other data, limited the models derived for this study. / AFRIKAANSE OPSOMMING: Die Barremiaanse tot Albiaanse silisiklastiese diepwater afsettings van die sentrale Bredasdorp Kom is hoofsaaklik in terme van stratigrafiese evolusie, afsettingskarakteristieke en fasies distribusie ondersoek. Kerne van die diepwater afsettings toon dat die fasies opeenvolgings uit massiewe, riffelkruis- tot parallel-gelamineerde sandstene, konglomerate, massiewe kleistene, afwisselende gelamineerde tot intergelaagde sandstene/slikstene en kleistene, sowel as gelamineerde en klei-ryke slikstene bestaan. Hierdie fasies word onderverdeel in kanaalopvulsel, plaatlob, oewerwal en komvlakte afsettings. Die toepassing van opeenvolgingsstratigrafie gebaseer op gammastraal en resistiwiteit log patrone toon dat alle 3de-orde afsettingsopeenvolgings uit 4deorde siklusse bestaan. Laasgenoemde word onderverdeel in drie komponente (lae-stand, transgressie en hoë-stand sisteemgedeeltes), gebaseer op vertikale fasies veranderinge en interne stratigrafiese sleutel vlakke. Korrelasie op ‘n regionale basis is moontlik gemaak deur die 13Amfs as die stratigrafiese verwysing vir elke boorgat te neem. Lae-stand afsettings, wat uit dik saamgevoegde massiewe sandstene bestaan, word geïnterpreteer as kanaalopvulsels. Die vertikale en horisontale stapeling van die sandstene vorm kanaalopvulsel komplekse bo Tipe 1 diskordansies. Naasliggende dungelaagde intervalle, wat uit parallel- tot kruisgelaagde sandstene bestaan, word geïnterpreteer as oewerwal afsettings, terwyl klei-ryke intervalle geïnterpreteer word as verteenwoordigend van komvlakte afsettings van hemipelagiese oorsprong. Fasies assosiasies en hul verspreiding toon dat kanaalvul geassosieër word met oorvloei afsettings en plaatsand eenhede. Hierdie afsettings, sowel as distale plaatsande geassosieër met klein kanaalopvulsels binne die 9A, 11A/12A, 13A en die 14A Opeenvolgings, word geïnterpreteer as afgeset in ‘n middelwaaier tot bo-waaier omgewing. ‘n Soortgelyke assosiasie bestaan in die 10A Opeenvolging, behalwe dat dik konglomeraat eenhede teenwoordig is by die basis van proksimale kanaalopvullings. Dit het gelei tot die interpretasie van die 10A Opeenvolging as afgeset in ‘n basis-van-helling tot bo-waaier omgewing. Die dikte van elke opeenvolging, soos verkry vanaf isochoor kaarte, toon ‘n kronkelende aksiale vloeipad wat ooreenkom met ‘n kanaalopvulling toevoerkanaal. Die aaneenlopende afname van hierdie kronkeling na bo in die opeenvolging word geïnterpreteer as verwant aan komvloer-beheer langs die hoof sand roetes. Opeenvolgende vloeie veroorsaak erosie-opvul-oorspoel prosesse, wat lokaal die konnektiwiteit van reservoirs oor groot areas bevoordeel. Herkenning van hoër-orde opeenvolgings en sleutel stratigrafiese vlakke dra by tot ‘n goeie begrip van die interne stratigrafiese verhoudings en ontbloot ‘n komplekse en dinamiese afsettingsgeskiedenis vir 3de-orde opeenvolgings. Beperkte boorgatbeheer en ‘n tekort aan seismiese en ander data het egter ‘n beperkende rol gespeel in die daarstel van modelle vir hierdie studie.

At head of title: National Centre for Petroleum Geology and Geophysics. / CD-ROM contains Appendices (1-10) in PDF. / Includes copies of papers co-authored by the author. / Includes bibliographical references (leaves [471]-499 in vol. 2) / System requirements for accompanying CD-ROM: Macintosh or IBM compatible computer with Windows NT. Other requirements: Adobe Acrobat Reader. / 2 v. (various pagings) : ill. (some col.), maps, ports. ; 30 cm. + 1 CD-ROM (4 3/4 in.) / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Studies the provenance and diagenesis of the Merrimelia Formation in South Australia and Queensland; a complex mosaic of glacial facies in which the Tirrawarra Sandstone and Merrimelia Formation exhibit an interfingering relationship, and defines the relationship further. Indicates that the Tirrawarra Sandstone should be included in the Merrimelia Formation as a "facies type" as both the Merrimelia and Tirrawarra sediments form an integrated suite of sediments. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology, 2000?

Includes bibliographical references.

Almost all sandstone beds occurring in the Upper Miocene formations at the Los Angeles basin were deposited by turbidity currents. Primary textures and structures indicative of turbidites occur in fair abundance throughout all three Upper Miocene formations. All accessible outcrops of the Puente, Modelo, and Upper Miocene portion of the Monterey and Capistrano Formations were scrutinized for sandstone beds containing primary sedimentary structures. Through study of these structures, the direction of current movement was determined. The pattern of current movement displayed reveals that sediment was being transported into the Los Angeles basin from all sides. Current directions and mineralogic studies indicate that essentially three source areas were supplying sediment into the basin. These source areas are 1) the San Gabriel Mountains, 2) an area to the east of the Santa Ana Mountains, and 3) a ridge of metamorphic rock paralleling the present coast line. The majority of sediment was derived from an area in the San Gabriel Mountains located northeast or the basin. This is evidenced by the fact that the thickness, grain size, and total sand content of the Upper Miocene units decrease southwestward across the basin.

At head of title: "NERDDC/SENRAC Research Project." / Three folded maps in pocket / Two microfiches in pocket / Bibliography: leaves 155-187 / 118, [70] leaves, [23] leaves of plates : ill. (chiefly col.), maps ; 30 cm. + 2 microfiches / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, National Centre for Petroleum Geology & Geophysics (NCPGG) /Dept. of Geology & Geophysics, 1993

At head of title: National Centre for Petroleum Geology and Geophysics. / CD-ROM contains Appendices (1-10) in PDF. / Includes copies of papers co-authored by the author. / Includes bibliographical references (leaves [471]-499 in vol. 2) / System requirements for accompanying CD-ROM: Macintosh or IBM compatible computer with Windows NT. Other requirements: Adobe Acrobat Reader. / 2 v. (various pagings) : ill. (some col.), maps, ports. ; 30 cm. + 1 CD-ROM (4 3/4 in.) / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Studies the provenance and diagenesis of the Merrimelia Formation in South Australia and Queensland; a complex mosaic of glacial facies in which the Tirrawarra Sandstone and Merrimelia Formation exhibit an interfingering relationship, and defines the relationship further. Indicates that the Tirrawarra Sandstone should be included in the Merrimelia Formation as a "facies type" as both the Merrimelia and Tirrawarra sediments form an integrated suite of sediments. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology, 2000?

La séquence sédimentaire du Dur At-Talah, située dans la partie sud du bassin de Syrte au centre de la Libye, est composée de 150 m d'épaisseur de roches principalement siliciclastiques (grès, siltites et argiles). L'importance de cette séquence est liée en partie à l'importance du bassin de Sirt qui est un des plus grands réservoirs d'hydrocarbures de Libye. La séquence est également un des plus important site de fossiles de vertébrés de l’Eocène supérieur, l'âge de la séquence. Les études antérieures, bien que très limitées par rapport à l'importance de cette zone, se sont concentrées principalement sur le contenu paléontologique de la séquence. L’étude sédimentologique n’avait été jusqu’à ce jour que très peu abordée. Cette thèse est un travail basé sur l’examen des affleurements et où l'accent est mis sur les structures sédimentaires et biogéniques (traces fossiles), visant à définir et à interpréter les faciès sédimentaires qui ont construit la séquence du Dur At Talah. L’ étude de la séquence a conduit à diviser la totalité de l’affleurement en trois intervalles génétiquement liés. Le plus ancien que nous avons appelé la « New Idam Unit » (environ 80 m d’épaisseur), est composé de grès très fins, de siltites et d’argiles. Cette unité (New Idam Unit) est recouverte en discordance par la « Sarir Unit » (environ 50 m d’épaisseur), composée de grès fins à moyens à faisceaux de litages entrecroisées dans sa partie inférieure (environ 25-30 m d’épaisseur) et de grès grossiers à microconglomératiques dans sa partie supérieure (environ 20-30 m d’épaisseur). La « Sarir Unit » est ainsi divisée en « Sarir inférieur » et « Sarir supérieur ». La « New Idam Unit » présente des dépôts qui sont attribués à un milieu main estuarien. La série débute par des dépôts d’environ 35 m d’épaisseur typiques d’un estuaire externe. Les 45 mètres qui lui font suite passent progressivement à des dépôts tidaux caractéristiques d’un estuaire interne. La Surface d'inondation maximale se situe entre les deux intervalles. Au-dessus de cette surface les indicateurs fluviaux augmentent et les indicateurs de marées diminuent progressivement, offrant ainsi un indice pour la migration de la rive de rivage vers le bassin (vers le Nord). La sous-unité du Sarir inférieur qui avait été interprétée avant ce travail comme dépôts fluviatiles, préserve pourtant des structures sédimentaires multi-échelles qui sont le résultat incontestable de processus de marée. Ceci est particulièrement évident dans la partie inférieure de l’unité « Sarir inférieur » (la Lower Lower Sarir Unit ; LLS). Dans la partie supérieure de l’unité Sarir inférieur (Upper Lower Sarir; ULS), les indicateurs de dynamique fluviale dominent largement sur ceux de la marée. Le Sarir inférieur est donc interprété comme un système deltaique mis en place lors d’une régression normale. Cette fois-ci, la surface maximale d'inondation se situe entre le LLS et ULS. Le « Upper Lower Sarir » (ULS) se terminée par une discordance subaérienne, avec de nombreuses traces d’émersion conservées au sommet de l'ULS. Celles-ci sont recoupées par le « Upper Sarir » qui montre des marqueurs fiables d'environnement de dépôt strictement fluvials. Les dépôts du « Upper Sarir » enregistre la séquence de bas niveau marin. Cette étude fournit des informations précieuses concernant le dépôt des séquences dans le bassin de Syrte au cours de la fin de l'Éocène. Elle fournit également une étude originale sur la dynamique tidale dans des milieux marins margino-littoraux. / Dur At Talah sedimentary sequence, located at the southern side of the Sirt Basin in central Libya, is composed of 150 m thick of mainly siliciclastic rocks. The importance of this sequence is linked to the importance of the Sirt Basin as one of large hydrocarbon reservoirs in Libya. The sequence is also an excellent site for vertebrate fossils of Late Eocene, the age of the sequence. Previous studies, though very limited compared to the importance of this area, are focused on its paleontological content. Sedimentology received only scant attention before this project. This thesis is an outcrop based study in which the focus is given to the sedimentary and biogenic (trace fossils) structures, aiming at defining and interpreting depositional facies which building up the sequence. The study is mainly based on field data which are analyzed on the light of related published literature and on the comparison with modern sedimentary environments. Results of facies analysis have led to splitting the entire sequence into three genetically related intervals. The oldest, we called the New Idam Unit (around 80m), is composed of very fine sandstones to mudstones. New Idam Unit is unconformably overlain by the Sarir Unit (around 50m), composed of medium grained cross bedded sandstones (the lower 25-30 m) changes up to very coarse and microconglomeratic sandstone (the upper 20-30 m). Thus, the Sarir Unit is split into the lower Sarir Subunit and upper Sarir subunit. The New Idam Unit presents both classical and unusual sedimentary and biogenic indicators that attribute this unit to estuarine depositional environment. It starts with outer estuarine (the lower 35 m) and ends up with inner estuarine (the upper 45 m). Maximum flooding surface is located in between. Above this surface the fluvial indicators increase and tidal indicators decrease, thus providing clue for basinward (North) migration of the shoreline. The lower Sarir subunit which was previously interpreted as fluvial deposits, preserves multi-scale sedimentary structures that undoubtedly belong to tidal processes. This is especially evidenced at the lower part of the lower Sarir Subunit (LLS). Fluvial indications over dominates the tidal ones in the upper part of the lower Sarir (ULS). Due to this configuration the whole lower Sarir subunit is interpreted as shallow marine, deltaic, depositional system, occurred during sea level ¨normal¨ regression. This time, maximum flooding surface is located between the LLS and ULS. The lower Sarir subunit is terminated by subaerial unconformity, with evidences of subaerial exposure preserved at the top of the ULS. These are intruded by the upper Sarir subunit which presents clear evidences of strictly fluvial environment of deposition. The deposits of the upper Sarir subunit record the low stand system tract part of the Dur At Talah sequence. In addition to the outlined results, the sequential pattern of the depositional events is suggested for the entire sequence of Dur At Talah. This study provides a valuable information regarding the depositional and sequential aspects of the Sirt Basin during the late Eocene, it also provide an unique case study for the better understanding of the shallow marine tidal deposits.

Hydrogeologists have faced serious challenges worldwide in the characterization of fractured rock aquifers due to the heterogeneous nature of the imbedded geology. The bulk flow parameters in the Karoo strata in South Africa are specifically uncertain since most models are based on homogenous block systems. As part of a WRC research project, entitled “Measurement of the bulk flow and transport characteristics of selected fractured rock aquifer systems in South Africa”, this study focuses on the characterization, borehole drilling, flow parameter measurements and groundwater quality assessment of the Balfour Formation in the Beaufort Group of the Karoo Supergroup in the Eastern Cape, South Africa, which is seriously heterogeneous in deposition and has also been largely neglected as drilling targets for groundwater. The Balfour Formation comprises mostly mudstone, shale and sandstone, formed in a braided and meandering river system. In addition to the heterogeneous deposition, the flow pathways in this aquifer system are not fully understood due to lack of actual measurement data. The methods used in this study include field mapping, site characterization, borehole drilling, and pumping and tracer testing in order to obtain the borehole yield, aquifer transmissivity, storativity and groundwater flow velocity. In addition, the groundwater chemistry was also studied to determine quality for use and possible connectivity with the nearby Tyume River and to determine potential sources of groundwater contamination. The results obtained include: 1) The study area is predominantly mudstone/shale with thin layers and lenses of siltstone and sandstone, which are interbedded; 2) Two boreholes were successfully drilled, which had yields in excess of 10 l/s in four water levels (at 7, 22, 54 and 65 m); 3) The estimated average transmissivity is 246 m 2/day according to the recovery test; 4) The estimated seepage velocity is 120 m/day according to tracer tests in the aquifer between the two boreholes which are 5 m apart; and 5) The water chemical type is the combination of HCO3-, Cl-and SO42- , which is distinguishable from that of the Tyume river; 6) There is no evidence for groundwater recharge to the deep aquifers from the Tyume river, based on the differences of the water chemistry; 7) The elements Ca, Cl, Na and C are distributed more than 90% as free ion species in BH2 borehole water; and 8) The groundwater in BH2 borehole is undersaturated (negative SI) with respect to some minerals (for example: anhydrite, fluorite, gypsum and halite), oversaturated (positive SI) with respect to some minerals (for example: aragonite, calcite and dolomite). It is concluded that there is a great potential to obtain drilling targets for high yielding boreholes in the sedimentary rocks of the Balfour Formation in the Karoo Supergroup.

The End-Triassic Extinction (ETE) has long remained one of the lesser known among the so-called “Big Five”. There exist several hypotheses regarding the probable cause of this extinction, which can mainly be divided into  events of  a decline in the rate of diversification  in the late Triassic contra a sudden and significant extinction event. Primary amongst the sudden events is the one of outgassing and climate/environmental change induced by Central Atlantic Magmatic Province (CAMP) volcanism. This  study  aims to  describe  the ETE using  fluvial, lacustrine, deltaic  and  marginal-marine  microbial sedimentary  structures (MS), carbonatized microbial mats (CMM) as well as  wrinkle structures, microbially  induced  sedimentary  structures (MISS) from the latest  Triassic-  earliest  Jurassic  (TJB: Triassic-Jurassic boundary interval, Rhaetian to Hettangian) of Skåne, Southern Sweden. The MISS in these sites show a high diversity of structures, indicating microbial communities with high diversity in an environment usually dominated by bioturbating invertebrates. We observed structures that include top-surface (“Elephant skin”) and subsurface (“Kinneyia”) structures, carbon-rich fossilized microbial mats, microbial sideritic concretions, sideritized microbial mats, stromatolite-like layers and oncoids. Scanning Electron Microscopy (SEM) sampling also revealed structures related to the presence of both coccoidal and filamentous cyanobacteria.  Overall,  the diversity in observed structures indicate a thriving microbial community, with diversified and abundant ichnofossils or body fossils of possible bioturbators only observed in the early Rhaetian and younger Mid-Late Hettangian samples of deltaic or marginal-marine affinities. The lack of metazoan communities to such an extent indicates that the local environment could have reversed to a pre-Substrate Revolution state. The occurrence of abundant and  diversified  microbial structures in the studied  TJB  section,  representing  a relatively  short time interval, reflects anachronistic facies and development of abnormal biota. This supports the occurrence of several environmental distresses (abnormal hydrochemical and physical conditions) on the Triassic-Jurassic boundary interval, in turn lending credence to the hypothesis of an abrupt climactic event such as possibly that of CAMP volcanism. / <p>Presentation was carried out online over zoom due to the at the time ongoing COVID-19 pandemic.</p> / Resurrecting a lost world in Skåne: new light on the end-Triassic mass extinction and the origin of the dinosaur dominated ecosystem / Dinosaur grave from Skåne: microbiology, taphonomy and paleomolecules of exceptionally preserved theropod remains