The Virginia Solite Quarry assemblage of Tanytrachelos ahynis, with its exceptionally abundant and uniquely preserved specimens, offers an opportunity to quantify multiple aspects of vertebrate taphonomy. The presence or absence of 128 skeletal elements (i.e., bones) as well as the presence or absence of 136 skeletal variables (i.e., morphometric dimensions) were recorded for 100 specimens collected from two distinct layers within the quarry (lake cycles 2 and 16). Anatomical specimen completeness (or the percent of bones/variables present in a specimen) is low (the median specimen preserves 14.5% of bones and 11.8% of measured variables) in spite of protection from high energy currents, predators, and scavengers afforded by anoxic bottom waters. Specimen size, as approximated by femur length, does not significantly impact specimen completeness. Also, post-exhumation weathering, duration of exposure before burial, and morphotype groupings do not appear to have significantly affected anatomical specimen completeness or articulation. Presence or absence of the enigmatic heterotopic bones represents a true biological signal as indicated by the lack of significant difference in anatomical specimen completeness between the two morphotypes as well as qualitative taphonomic evidence. When anatomical specimen completeness has been corrected for post-depositional faulting, lake cycles 2 and 16 differ from one another significantly in terms of articulation and anatomical completeness of specimens. Specimens with soft-bodied preservation are significantly more articulated, but not significantly more complete, than specimens without preserved soft tissues. Preservation frequency of bones/variables (or the percent of specimens in which a bone/variable is present) varies greatly, but is generally low (an average skeletal element is present in 19% of specimens and an average variable can be measured in 12% of specimens), with significant preferential removal of smaller skeletal elements. Hind limbs, specifically femora, are most commonly preserved. Low anatomical specimen completeness and positive correlation between bone size and frequency of preservation both indicate specimen disturbance by minor hydraulic currents. These taphonomic patterns suggest a moderate-depth depositional environment (slightly shallower than previously proposed). / Master of Science

>Magister Scientiae - MSc / This study is located within the Bredasdorp Basin which is on the southern continental margin, offshore South Africa. The basin is located between Infanta and Agulhas arches and is a rift basin that is southeastern trending. Sedimentology reports have shown that the basin is predominantly filled by Aptian to Maastrichtian deposits which overlays pre-existing late Jurassic to Early Cretaceous fluvial and shallow marine syn-rift deposits. Devonian Bokkeveld Group slates and or Ordovician-Silurian Table Mountain Group quartzites are shown to be the composition of basement rocks. The study area incorporates only three wells for this research; well F-AH1, F-AH2 and F-AR1. This paper was completed through analyzing and juxtaposing interpretations of results from gamma ray wireline log analysis with core analysis in which these correlations and figures were displayed using Petrel software and Coral Draw respectively. Core analysis resulted in the identification of, sixteen litho-facies for the entire study, which were recognized according to its grain size, texture, sedimentary structures, colour changes, base and top contacts, bioturbation, noticeable minerals, etc. Facies tend to alternate all the way through each well and between different wells with similar facies being present in different wells, but they are not evident in all the cores. Based on the classification of sand bodies, core analysis provides good indication that the general depositional environment of reservoirs within the studied wells are within a marginal marine depositional environment which are tidally influenced. Log signatures typical of sandstone reservoir bodies were discovered in the field where sand bodies are 20 m thick or less and were recognized in the study area. Depositional environments were characterized based on depositional environment similarities: a funnel-shaped facies representing a crevasse splay; a cylindrical-shaped facies representing slope channel-fills representing the transgressive-regressive shallow marine shelf.

The sequence stratigraphy, depositional systems and reservoir geology of the lower and middle Oligocene Frio Formation in the Red Fish Bay field, Nueces County, Texas, are examined based on 1,800 feet (548.6 m) of core, 28 wireline-logs and 30 mi2 of 3-D seismic data. The study interval is composed of an incomplete 3rd-order stratigraphic sequence with an incomplete lowstand systems tract (LST), a complete transgressive systems tract (TST) and an incomplete highstand system tract (HST). This 3rd-order succession is divided into 12 4th-order sequences with average thickness of 150 feet (45.7 m). The lowstand system tract (LST) from 4th-order sequence 1 to 4th-order sequence 7 displays an aggradational stacking pattern in cross-sections. The regressive part of each 4th-order sequence has an upward-coarsening trend that reflects a transition of depositional environments from offshore to lower, middle and upper shoreface. The transgressive part of each 4th-order sequence exhibits an upward-fining trend, commonly associated with backstepping cycles composed of shoreface, washover-fan, and back-barrier lagoonal deposits. Sandstone maps of 4th-order sequence and stratal-slice maps from 3-D seismic data within 3rd-order lowstand system tracts display a strike-elongate geometry, indicating wave-dominated depositional systems. The 3rd-order transgressive system tract (TST) displays a retrogradational stacking pattern in cross-sections. The overall upward-fining trend records water deepening during transgression, interpreted as a transition from lower-shoreface to shelf environments. The 3rd-order highstand system tract (HST) from 4th-order sequence 8 to 4th-order sequence 12 displays a progradational stacking pattern in cross-sections. It is upward-coarsening and upward-thickening, indicating a transition from to distal- to proximal-shoreline setting. The geometry of framework sandstone bodies, inferred from gross-sandstone and stratal-slice maps is relatively lobate, suggesting a wave-modified deltaic system. The sandstone body continuity is very good and heterogeneity is very low within shoreface or wave-dominated deltaic systems in LST and HST sequences in Redfish Bay. Sandstone thickness expands towards the growth fault, owing to structurally controlled accommodation, but is thicker in the southwest part of study area, where it is controlled by paleogeomorphology, related to the presence of a deltaic depocenter. The sandstone body thickness of each 4th-order sequence is as much as 240 ft (73.2 m) and commonly ~100 ft (30.5 m) in average. Sandstone development in the study succession is controlled by the sequence stratigraphic context, and modification by depositional processes. The average porosity and permeability of study interval are 19.4% and 33.6 md respectively. Lithology is the main control on porosity and permeability. Sedimentary and biogenic structures also modify grain-size sorting, indirectly affecting porosity and permeability. Reservoir quality in LST is higher than that in the HST, as the depositional environment in LST is within proximal-delta-front facies, whereas in the HST is within distal-delta-front facies. Reservoir quality varies greatly within each 4th-order sequence, owing to different levels of intensity in bioturbation per each sandstone bed. / text

>Magister Scientiae - MSc / Durban Basin located on the eastern coast of South Africa has been a focus of interest for Petroleum Exploration for the last few decades. Only four exploratory wells have been drilled in this offshore basin without success. During the initial stage of its creation, the basin suffered major tectonic disturbance as evident from the presence extensional faults followed by intense igneous activities. This was followed by marine sedimentation in the late Mesozoic (late Jurassic-early Cretaceous). An attempt has been made in this work to understand the distribution of the rock in space and time for the early Cretaceous sediments considered most prospective for hydrocarbon exploration in Southern Africa. Temporal distribution of planktonic foraminifera helps in identification of the three early Cretaceous (Barremian to Albian) stages within the drilled intervals. Foraminiferal biostratigraphic studies integrated with sedimentology, log motif analysis and seismic data analysis helps to predict paleodepth and depositional environment during early Cretaceous in this research. / 2022-04-30

The Wilcox Group includes the most abundant lignite bearing strata in Mississippi. Currently, the only lignite mine in Mississippi is located in Choctaw County with a proposed mine in Kemper County. Six lignite seams are currently mined in Choctaw County. One of those seams is believed to be continuous, from SE Choctaw County through central Winston County, NE Neshoba County into SW Kemper County (roughly 50 miles). Establishing a cross section from Choctaw to Kemper County verifying a continuous lignite seam would provide a stratigraphic marker horizon in correlation along strike, which is uncommon in the Wilcox Group sediments. Through observation of over 60 geophysical logs from test wells along strike, SEM and petrographic microscopy, the lignite seam was verified as being continuous from the mine in Choctaw County to the new proposed site in Kemper County and should be used as stratigraphic marker horizon for correlation along strike.

>Magister Scientiae - MSc / Southern offshore basins of South Africa are well known as potential provinces of hydrocarbon exploration and production. The complex nature of the Bredasdorp sub-basin’s syn-rift architecture (transform fault system) can have adverse effects on reservoir distribution due to periodic local and regional uplift of horsts and grabens. This present investigation focusses on an integrated approach of the 1AT1-V horizon or early Cretaceous sediments in the Bredasdorp sub-basin to identify the depositional environment and provenance of these sediments as well as their role in regionally complex compositional heterogeneities associated with the late stage rifting of Gondwana break-up. An integrated seismic, sedimentological (including petrography and geochemistry) and ichnologic analysis of the 1AT1-V horizon sediments showed an overall lower regressive element complex assemblage set and an upper transgressive element complex assemblage set that occurred as a >120m thick succession. The analysis identified a mixed-energy deltaic succession followed by an estuarine succession. The 1AT1-V interval (late syn-rift) consisted of nine sedimentary facies associations (and associated petrofacies) on a dipslope setting with variations occurring along the strike and the downdip depositional slope areas. Two overall sequences were identified as a lower regressive and upper transgressive sequence (Element complex assemblage sets). The regressive sequence consisted of middle to distal delta front lobe fringes, hyperpycnal event beds (sourced from basement highs), offshore migrating tidal bars (and associated inter-bar regions), distal mouth bars, terminal distributary channels (and associated inter-terminal distributary regions). The distal delta plain to proximal delta front consisted of interdistributary bays, distributary channels, crevasse splay sub-deltas, mouth bars, tidal flats and offshore embayments. In the laterally isolated depocenter, these deposits also consisted of basement high slopes with upliftment of the basement highs leading to proximal/central embayment to regressive shoreface/foreshore environments. These sequences consisted generally of low diversity and intensities (impoverished abundances) of trace fossils. The paleoclimate inference from this sequence indicates a humid climate with intermediate degrees of weathering intensities (possibly fluctuating arid-humid conditions). The transgressive sequence consisted of estuarine sedimentation with the occurrence of tidal sand ridges and compound dune fields, embayment facies and tidal bars. These sequences consisted of relatively higher ichnodiversities and intensities than their relative regressive sequences. The paleoclimate inference during these times consisted of more arid to semi-arid settings with low degrees of weathering in the source terrain. Local tectonic upliftment and subsidence, with exposed basement highs, gave rise to differential process regimes (tidal, wave and fluvial) and hence depositional facies in the diachronous updip/downdip areas (spatial) and within-stratigraphic (temporal) variations. There are several modern analogues that are similar to the 1AT1-V horizon sequence and they are the Mahakam, Ganges-Brahmaputra, Po, Burdekin deltaic and Satpara lake environments Compaction and dissolution diagenetic features as well as transportation were responsible for the major compositional heterogeneities concerning the reservoir quality and distribution. Proximal and distal sources were identified with first cycle and polycyclic sediments being deposited in the northern and southern part of the basin during the late stages of rifting in the Bredasdorp sub-basin. The provenance lithology has been identified as recycled sedimentary rocks (and their meta-equivalents) with an ultimate source terrain that was largely felsic in nature (Cape granite suite). The northern part of the studied section is suggested to have received sediments from the main metasedimentary rocks of the Cape fold belt (including the Table Mountain Group and Bokkeveld Group) whereas the southern sections received more sediments from the basement highs (recycled Malmesbury Group (and Pre-Cape sediments) and Cape granite suite), which is further supported by seismic data. Provenance analysis revealed that the Cape Fold belt (most recent collision) was possibly a provenance terrain but overprinting of several collisions are also acknowledged. The tectonic setting was envisaged to be of a rifted margin during the break-up of Gondwana. This compositional heterogeneity due to facies and provenance-related terrains had major consequences to the reservoir quality and distribution from the northern part to the southern part of the studied section

<p> The transition from the Whirlpool Sandstone to the Manitoulin Dolomite represents a marine transgression. Within the Manitoulin Formation, the proportion of siliclastics to carbonates shows a marked upward decrease. The Manitoulin Formation consists of four main facies. The lower two facies indicate an inner shelf environment, while the upper two represent a middle to outer shelf environment. </p> <p> These sediments have been almost totally dolomitized. Cathodoluminescent microscopy was employed to determine the diagenetic history of quartz, calcite, and dolomite cements. The petrographic characteristics of the dolomite using CL and normal light indicate a late stage (epigenetic) dolomitization. </p> <p> Dolomitization is thought to have been a late diagenetic process brought about by Mg-rich fluids expelled during compaction of adjacent shales and supplemented by brines circulating through fracture systems. </p> / Thesis / Bachelor of Arts (BA)

<p> A sedimentogical and petrological examination of the basal sands of the Stoddart Formation in the area of Josephine field has been undertaken. The determination of the depositiianal environment and the history of sedimentation of the basal Stoddart sands are the objectives of this study. </p> <p>The thick sands at the base of the Stoddart Formation which have a blocky gamma ray response consist of fine-grained sandstone dominated by angle of repose cross-bedding. The sedimentary structures, stratification types, composition and facies relationships of these sands indicate that they are of a coastal aeolian origin.</p> <p>The compositional, textural and surface texture characteristics of these sands were studied under petrographic, cathodolumenescent and scanning electron microscopes. Observations indicate that the above criteria can be used to support the interpretation of an aeolian origin for the cross-bedded sands of the basal Stoddart Formation. </p> <p>The sands of the basal Stoddart show rapid transitions between sub-aerial and marine environments. These rapid changes are believed to be caused by sudden sea level fluctuations resulting from movement of reactivated faults in the Peace River arch area. </p> / Thesis / Bachelor of Science (BSc)

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