Automated detection of geological boundaries and determination of cyclic events controlling deposition can facilitate stratigraphic analysis and reservoir characterization. This study applies the wavelet transformation, a recent advance in signal analysis techniques, to interpret cyclicity, determine its controlling factors, and detect zone boundaries. We tested the cyclostratigraphic assessments using well log and core data from a well in a fluvio-eolian sequence in the Ormskirk Sandstone, Irish Sea. The boundary detection technique was tested using log data from 10 wells in the Apiay field, Colombia. We processed the wavelet coefficients for each zone of the Ormskirk Formation and determined the wavelengths of the strongest cyclicities. Comparing these periodicities with Milankovitch cycles, we found a strong correspondence of the two. This suggests that climate exercised an important control on depositional cyclicity, as had been concluded in previous studies of the Ormskirk Sandstone. The wavelet coefficients from the log data in the Apiay field were combined to form features. These vectors were used in conjunction with pattern recognition techniques to perform detection in 7 boundaries. For the upper two units, the boundary was detected within 10 feet of their actual depth, in 90% of the wells. The mean detection performance in the Apiay field is 50%. We compared our method with other traditional techniques which do not focus on selecting optimal features for boundary identification. Those methods resulted in detection performances of 40% for the uppermost boundary, which lag behind the 90% performance of our method. Automated determination of geologic boundaries will expedite studies, and knowledge of the controlling deposition factors will enhance stratigraphic and reservoir characterization models. We expect that automated boundary detection and cyclicity analysis will prove to be valuable and time-saving methods for establishing correlations and their uncertainties in many types of oil and gas reservoirs, thus facilitating reservoir exploration and management.

The storm-dominated paleotropical carbonate succession exposed on Anticosti Island in Eastern Canada represents one of the most complete, thickest, and well-preserved successions in the world spanning the O/S Boundary. This study develops a new high resolution integrated lithostratigraphic, cyclostratigraphic, and chemostratigraphic framework for the upper Hirnantian to lower Telychian (Upper Ordovician to lower Silurian) succession on Anticosti, by examining ~450 m of strata from a recent stratigraphic drill core (Martin La Mer), supplemented by ~120 m of outcrop, all from the south-central part of the island. Four facies assemblages and three time-specific facies were identified in this succession and can be organized into three orders of superimposed transgressive-regressive cycles. New high resolution isotopic curves were produced by sampling well-preserved bulk micrite at a resolution of 0.5-1.0 m per sample; in total 443 samples were taken from core and 168 from outcrop, corresponding to the Ellis Bay, Becscie, Merrimack, Gun River, Menier, Jupiter and Chicotte formations. Four distinct positive carbon isotope excursions are recognized in the study interval; the upper Hirnantian (+5‰), Lower Aeronian (+2‰), Upper Aeronian (+6‰), and Valgu (+3.5‰) excursions. These δ13C excursions accompany lithology, and sea level changes and are likely driven by transitions between humid and arid climate states coupled with ocean changes. Multi-ordered δ18O trends are recognized to occur in association with δ13C trends; long-term and intermediate scale δ18O fluctuations are likely controlled by glacio-eustasy and Silurian climate fluctuations, while high-frequency fluctuations may record an astronomical forcing signal.

Anticosti Island, located in Eastern Canada, displays one of the most complete, best exposed, and most fossiliferous carbonate successions spanning the Ordovician-Silurian (O/S) Boundary in the World. This study develops a new high-resolution framework for the post End-Ordovician extinction strata (~ 260 m thick) exposed in coastal outcrops and recovered from a continuous drill core (La Loutre #1), both located in the western part of the island. In total, eight facies, all associated with a storm-dominated carbonate system, were recognized and organized into a multi-order depositional cycles. A new high resolution isotopic curve with more than 300 data points from well-preserved bulk micrite samples covers the late Hirnantian to Early Aeronian time interval and corresponds to the upper Ellis Bay, Becscie, Merrimack and lower Gun River formations. Two distinct positive carbon isotope excursions are present in the late Hirnantian part of the Ellis Bay Formation (+5‰) and in the lower Aeronian part of the Gun River Formation (+2‰). These positive isotopic carbon excursions provide a distinctive chemostratigraphic signature for regional and global correlations with other O/S sections. Like the Quaternary δ18O marine signal, our δ18O record is largely coupled with multi-order cyclic facies changes. This study demonstrates the importance of glacio-eustasy following the End-Ordovician glacial maxima as one of the primary factors controlling the stratigraphic architecture of paleotropical neritic carbonates during the Early Silurian.

High resolution sampling was performed along the &Uuml / z&uuml / ml&uuml / Formation exposed near the YeniceSihlar village of Mudurnu (Bolu). Field and thin-section analyses showed that the &Uuml / z&uuml / ml&uuml / Formation is composed of cm to m scale cycles of 4th and 5th order. The 4th order cycles are equivalencies of parasequences and have 0.4 Ma average duration. 5th order cycles are interpreted as episodic. Upper Albian (OAE1c or OAE1d) and Cenomanian/Turonian (OAE2) anoxic events are observed as black shale levels in the studied section. Position of black shale levels is interpreted using cyclostratigraphy and sequence stratigraphy. Four types of cycle are determined. A and B-type cycles are placed in transgressive and Highstand System Tract. C and D-type cycles are placed in Lowstand System Tract. Two type 3 and one type 1 sequence boundaries are recorded. The boundary between the Soguk&ccedil / am Limestone and the &Uuml / z&uuml / ml&uuml / Formation is interpreted as the first type 3 sequence boundary. The second one separates the &Uuml / z&uuml / ml&uuml / Formation and the Yenipazar Formation and is observed at the top of the section. Type 1 boundary is represented by a conglomeratic level in the middle of the succession. Provenance analysis of sandstones indicates that during the Cenomanian the source area changed from magmatic arc setting to continental setting.

The offshore facies of the basal Lias of S.Britain was studied as a typical example of an open-marine cyclic sequence. The sedimentology, geochemistry and power-spectral analysis were investigated in order to understand the cause of the interbedded rock types. Three sediment types were deposited on the sea-floor: light marl, dark marl and laminated carbonate-rich shale. Calcite microspar, the dominant carbonate component, appears to have been formed from the neomorphic aggradation of coccoliths supplied in zooplankton faecal pellets. During sulphate reduction, the most carbonate-rich horizons in the light marl and laminated shale beds were cemented by carbonate, producing early diagenetic limestone and laminated limestone beds and nodules. Walsh power-spectral analysis of several measured sections in the basal Lias indicate that two regular sedimentary cycles, with periods of tens of thousands of years, are present. The regularity, stability and periods of the cycles invokes the Milankovitch Theory of orbital forcing of sedimentation; the cycles thus probably represent periods of 41,000 and 21,000 years. The sedimentation appears to have been linked to climatic variation by the levels of runoff and the formation and destruction of wedges of brackish water. During dry periods relatively little runoff and low clay input allowed turbulent, oxygenated bottom-waters and the deposition of burrowed, organic-poor marl. During wet periods, brackish wedges caused widespread density stratification, bottom-water anoxia and high clay inputs that resulted in laminated shale beds. Walsh power spectra were generated for one Silurian, five Upper Lower Jurassic, one Kimmeridgian and one Oligocene formation. Unexpectedly the Early Jurassic appears to have been dominated by the Milankovitch cycles related to obliquity and precession rather than eccentricity. Of the thirteen spectra produced, including five from the basal Lias, ten (or about 80%) contain evidence for regular sedimentary cycles consistent with orbital forcing of sedimentation. Therefore the Milankovitch Theory should be considered whilst investigating open-marine 'cyclic' sequences.

Thesis (M.S.)--Brigham Young University. Dept. of Geology, 2004. / Includes bibliographical references (leaves 187-189).

The carbonate storm-dominated sedimentary succession superbly exposed on Anticosti Island in Eastern Canada represents one of the most complete and well-preserved paleotropical stratigraphic records spanning the Ordovician-Silurian (O-S) boundary. We sampled the nearly continuous coastal outcrop exposed at low tide along the west coast of Anticosti Island for high-resolution δ13C and δ18O chemostratigraphy. These new isotopic curves comprise more than 500 data points spaced at ~0.6 m intervals; for a total of 320 m of strata across the O-S boundary. The δ13C curve displays two distinctive positive excursions in the Hirnantian Ellis Bay Formation; a small lower excursion (+2.5‰) and an upper larger excursion (+4.5‰). These two positive isotopic carbon excursions provide a distinctive chemostratigraphic signature for regional and global correlations with other Hirnantian sections. The continuing descending δ13C trend, at least 30 m above the currently interpreted O-S boundary, suggests a readjustment of that boundary on the Anticosti succession. The δ18O curve, similarly to the Quaternary δ18O marine curve, is tightly coupled with multi-order cyclic facies changes. Our tightly coupled lithological and oxygen isotopic data suggest that the Anticosti succession was influenced by glacio-eustatic fluctuations during the end-Ordovician. Furthermore, the estimated duration of these multi-order cycles supports an astronomical forcing. A primary isotopic signal record is also supported by the lack of significant covariance between δ13C and δ18O, by the excellent microfabric preservation of both macro and microfossils in petrographic, cathodoluminescence, and SEM microscopy, and by little or no diagenetic resetting as suggested by the trace element geochemistry, which is unusual in the deep geological time.

The diploma thesis studies lithofacies and cyclic pattern of about 200 m thick upper part of the Poruba Member (Serpukhovian) in the Karviná area of the Ostrava-Karviná coalfield. The objective of this thesis is to identify laterally persistent cycles from the local ones by the set of cross-sections and to better understand their formation, especially the role of glacio- eustatic sea level changes. Set of cross-sections constructed from boreholes were used for this study. The three genetic cycles were identified in the thesis based on previous studies of Gastaldo et al. (2009). From base to top the cycles are the (i) Max, (ii) Otakar a (iii) Gaebler. Their thickness fluctuates between 19.9 and 109.9 meters. The genetic cycles are bounded, with one exception, by a transgressive erosional surface of important faunal marine bands. From the set of cross-sections and maps of thickness and sand content (%), constructed for individual genetic cycles, it is obvious that the area of maximum thickness corresponds to area of increased content of medium- and coarse-grained sandstone. Maxima of sand content and thicknesses follow NNE-SSW direction, which is in agreement with basin axis. These maxima are interpreted as areas occupied by fluvial channels that are responsible for deposition of coarse- grained...

This master thesis studies cyclic pattern of the Nýřany Member (Middle Pennsylvanian, Moscovian) in the Slaný coalfield situated in the Kladno-Rakovník Basin. The main objective is to identify laterally persistent cycles and to find out their possible origin. Set of cross-sections constructed from boreholes proved lateral stability of 40 - 60 m thick units called the mesocycles. In all, eight mesocycles were identified (N0 - N7), of which the mesocycle N7 was newly defined. Maps of thickness and sand content constructed for each mesocycle provided additional information on subsidence rate and distribution of clastic sediments by fluvial processes. Lateral stability of the mesocycles suggests their allocyclic character and regionally operating mechanism responsible for their formation. Regularity in repetition of the mesocycles as indicated by their similar thicknesses and architecture may suggest that the mechanism could be periodic, possibly of climatic origin. This hypothesis is supported by calculated mean duration of the mesocycles to be ~ 400 ky, based on previously published high-precision CA-ID-TIMS radioisotopic ages of intercalated tonsteins. This "periodicity" approaches 413 ky periodicity of the long eccentricity, one of the Milankovitch orbital cycles, which, in turn, is considered here...

The Montian Kartal Formation lies in the south-west of Ankara region and overlies the Upper Cretaceous Beyobasi Formation and is overlain by Thanetian Kirkkavak Formation conformably in the studied region (Kayabasi village, NW of town of Haymana). A 283 m stratigraphic section, which is mainly composed of an alternation siliciclastic and carbonate rocks has been measured in the Kartal Formation within the Haymana-Polatli basin. The aim of this study is to carry out the sedimentological and cyclostratigraphical analyses of the upper part of the Kartal Formation within Haymana-Polatli basin which represents a well developed cyclic pattern. In this study, detailed lithofacies analyses were performed and four different facies were recognized along the measured section: sandstones, limestones, mudrocks and conglomerates. Sedimentological analyses, such as modal, provenance, palaeocurrent, grain-size and grain parameters were also performed and their relation with the depositional environment and change in depositional conditions were discussed. Interpretations of the depositional environment revealed that the deposition occurred by low sinuosity rivers and waves. Additional environmental interpretations suggested that the sediments were deposited in shallow marine and/or coastal (beach) environments. High resolution cyclostratigraphy studies based on meter scale cyclic and rhytmic occurrences of lithofacies along the measured section were performed. The whole section, which is 283 m thick, was divided into large-scale hierarchy-cycles which comprise smaller-scale fining upward and deepening upward cyclic and rhythmic beds.