DOCSLIB.ORG

Evolution of Extensional Systems

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Evolution of Extensional Systems Faculty of Science Masaryk University Department of Geological Sciences Evolution of Extensional Systems Literature Thesis in Requirement for Masters Author: B.Sc. Cameron Sheya Supervisors: Assoc. Prof. RNDr. Rostislav Melichar, Dr., Prof Michal Nemˇcok, DrSc. Brno, Czech Republic 2010 Contents Table of Contentsi Preface ii 1 Classification of rift systems: Basics1 1.1 Continental Rifts................................1 1.1.1 Narrow Rifts..............................2 1.1.2 Wide rifts................................2 1.2 Pull-apart basins................................5 1.3 Back-arc Basins................................. 10 1.4 Cratonic Sags.................................. 11 2 Rift system linkages and geometries 16 2.1 Fault geometries and linkages......................... 16 2.2 Fault linkages.................................. 18 2.3 Sub-basin interactions and the role of extension geometry in the process.. 22 3 Pull-apart basin development and geometries 28 3.1 Basic basin evolution and resulting geometries................ 28 Bibliography 38 i Preface The purpose of this literature thesis is to create a concise report on the extension and associated basin types and their subsequent history in the orogenic foreland setting. This thesis was written with the intent of first classifying the types of extensional basins and then describing their evolution. The understanding of the basin dynamics throughout their history will help in interpreta- tions of past and present day tectonic regimes. Final chapters discuss characteristics and dynamics of foreland basins including potential inversion of pre-existing extensional basins. ii Chapter 1 Classification of rift systems: Basics 1.1 Continental Rifts Continental rifts are areas where extension of the continental lithosphere leads to a subsid- ing basin.It is broken by several normal faults or several sets of normal faults, which can lead to either passive or active upwelling of the hot asthenospheric material underneath the area of the rift (Allen & Allen, 1990, 2005; Brun, 1999). Good examples of continental rifts come from the Basin and Range Province in the Western United States (Hamilton, 1987) and East African rift (Rosendahl, 1987). Extension within these continental rift systems continuously evolves until subsequent re- gional tectonic process either changes the existing local tectonic regime into another, (e.g. change from rifting to thrusting) or some process halts the extension, (e.g. the lack of sufficient stresses to control faulting) (Withjack et al, 2002). Continental extension has several associated factors such as: • high heat flow in the extended basin (Allen & Allen, 1990; Behn et al, 2002); • high temperature gradient from the basin to the un-extended margins (Allen & Allen 1990); • negative gravity anomaly (Prieto, 1996, Allen & Allen 2005); • internal structural highs, which may sometimes become inverted sedimentary prove- nances for deposition in the basin (Allen & Allen, 1990); • possibility associated magmatism due to the upwelling of hotter material from the asthenosphere (Behn et al, 2002); 1 1.1 Continental Rifts 2 • if the basin itself has emplaced basalt or granite, it will result in a positive magnetic anomaly (Prieto, 1996) and; • changes in isostacy. Continental rifts can be classified into narrow and wide rifts (Allen & Allen, 1990; Brun, 1999). Narrow continental rifts are areas of extension in the lithosphere that result in a stretching instability when the geotherm is higher than normal and the crustal thickness is in the range of 30-40 km whereas wide rifts are wider than the thickness of the lithosphere in which they occur (figure 1.1 ; Brun, 1999). 1.1.1 Narrow Rifts Narrow rifts are typically found in areas that have thermal anomalies which are associated with: • previous thinning of the lithosphere; • in areas with high mantle strength (Gueydan et al., 2008); • localized magmatism either from tectonic reasons or the influence of a hotspot; and/or • regions of localized strain weakening that affects the stronger layers of the continental lithosphere (Buck, 1991). Passive margins are incorporated into the classification of narrow rifts due to the thickness of lithosphere in which they generally evolve. Pre-rift rheology and thermal conditions of the crust play an integral role in determining the type and geometry of the rift. Passive margins are similar to the aforementioned continental rift systems, however; the upwelling of the Moho and asthenosphere is more pronounced in the formation of a passive margin. This upwelling of the Moho and asthenosphere usually has a longer wavelength than the width of the rift itself. Passive margins usually have a width range from around 100 km to 400 km (Brun, 1999). Examples of this rift type are found on the entire coastal margin of Africa, eastern margin of North America and the coastal margins of Australia among other coastal regions throughout the world (figure 1.2). 1.1.2 Wide rifts Wide rifts are wider than the thickness of the lithosphere in which they occur (Allen & Allen, 1990; Brun, 1999). The extensional event in the wide rift settings take place 1.1 Continental Rifts 3 (a) (b) Figure 1.1: (a) Idealized narrow rift with examples of passive margins and oceanic rift stages; (b) wide rift system, note how the brittle lithosphere has been thickened due to a previous compressional event (Brun, 1999) 1.1 Continental Rifts 4 Figure 1.2: Global distribution of passive margins. Compiled from Melluso et al., 2002; Geoffroy, 2005; Watkeys, 2002; Leroy, 2008. 1.2 Pull-apart basins 5 after a period or multiple periods of lithospheric thickening that can be associated with a subduction or area of collision setting. Wide rifts are known to reach widths of up to 1000 km (Brun, 1999) and are usually separated into sub-basins. An example of a wide rift that has been separated into sub-basins is the Basin and Range Province in the Western United States. This rift contains several tilted horst blocks that separate the individual sub-basins (Hamilton, 1987). Wide rifts are usually characterized by a horst-and-graben architecture and the frequent occurrence of core complexes (Hamilton, 1987; Brun, 1999). The models of Gueyadan et al., (2008) have shown that wide rifts occur in areas where the lower crust is very ductile and weak which leads to a more wide spread fracturing of the brittle crust. Core complexes occur in areas with a very low angle normal detachment fault that allows the hotter and more ductile material to protrude through the tilted blocks of a wide rift sys- tem (Allmendinger and Platt, 1983; Brun et al., 1994; Brun, 1999). When a core complex is forming, the extension of the upper crust is largely localized whereas the extension of the lower crust is much more broadly distributed (Allmendinger and Platt, 1983). The ductile material of the lower crust is then exhumed and exposed by a system of low angle normal faults. The exhumed material is then eroded and uplifted which leads to the exhumation of highly metamorphosed rocks (Brun, 1999). These core complexes tend to occur in areas that have larger than normal heterogeneities in the crustal lithosphere (Brun, 1999). Wide rifts occur by definition over a large area, which accounts for large differences in the amount of strain throughout the whole basin (Hamilton, 1987). Therefore, there can be a multitude of different fault expressions, including low angle detachments of core complexes, and high-angle normal faults between the horsts and grabens, scattered throughout the basin as a whole (Allmendinger and Platt, 1983; Brun et al., 1994). 1.2 Pull-apart basins Pull-apart basins are structural depressions that are formed by localized zones of extension within an area of strike-slip deformation (figure 1.3 (a) ;(b); 1.4; Carey, 1958, Rahe et al., 1998). The areas of extension occur in the accommodation zone between two strike-slip branches that are nearing each other (Rahe et al., 1998; Sims, 1999). As the area between these two main controlling faults continues to become fractured, the subsequent linking and accommodation space created by this movement will create a subsiding extensional basin (Allen & Allen 1990). The resulting shape from the localized extension is usually rhombic (figure 1.3 (a) ;(b); 1.4; Price and Cosgrove, 1990; Rahe et al., 1998; Sims et al., 1999). The process of fault linking and subsequent extension and subsidence evolves as follows: • R shears begin to form throughout the accommodation zone between the two linking 1.2 Pull-apart basins 6 (b) (a) Figure 1.3: (a) Model set up from Rahe (1999) showing the initial parameters of a pull- apart system; (b) after deformation of the model in (a) showing the relative movements and area of accommodation (Rahe, 1999). strike-slip faults. The R shears have the same sense as the overall strike-slip regime (figure 1.5 (a); (b), Allen & Allen, 1990; Twiss & Moores, 1992). • as the basin continues to evolve, R' shears begin to propagate through the accom- modation zone. They have a displacement that is opposite to that of the overall strike-slip sense (figure 1.5 (a) ;(b); Allen & Allen, 1990; Sims et al., 1999). • subsequently, P shears begin to develop through the accommodation zone, having the same sense as the overall movement of the strike- slip system (figure 1.5 (a) ;(b); Allen & Allen, 1990). Tension fractures and normal faults are being developed inside the pull-apart basin apart from the mentioned R, R' and P shears (Allen & Allen 1990). • the final stage of linkages in a pull-apart basin is when the various fractures and faults hard-link the two controlling strike-slip faults together (Allen & Allen 1990). The evolution of a pull-apart can be divided into three stages (Rahe et al., 1998): 1. incipient; 2. early; and 3. mature. The incipient stage of a pull-apart is characterized by the initiation of graben or half graben which is oriented parallel to the oblique step located between the controlling strike-slip faults (figure 1.5 (a) ;(b);1.6; Rahe et al., 1998; Sims et al., 1999).
Load more

Recommended publications
  • Chapter 1 -- the Place of Faults in Petroleum Traps
    Sorkhabi, R.,and Y. Tsuji, 2005, The place of faults in petroleum traps, in R. Sorkhabi and Y. Tsuji, eds., Faults, fluid flow, and petroleum traps: AAPG Memoir 85, 1 p. 1 – 31. The Place of Faults in Petroleum Traps Rasoul Sorkhabi1 Technology Research Center, Japan National Oil Corporation, Chiba, Japan Yoshihiro Tsuji2 Technology Research Center, Japan National Oil Corporation, Chiba, Japan ‘‘The incompleteness of available data in most geological studies traps some geologists.’’ Orlo E. Childs in Place of tectonic concepts in geological thinking (AAPG Memoir 2, 1963, p. 1) ‘‘Although the precise role of faults has never been systematically defined, much has been written that touches on the subject. One thing is certain: we need not try to avoid them.’’ Frederick G. Clapp in The role of geologic structure in the accu mulation of petroleum (Structure of typical American oil fields II, 1929, p. 686) ABSTRACT ver since Frederick Clapp included fault structures as significant petroleum traps in his landmark paper in 1910, the myriad function of faults in petroleum E migration and accumulation in sedimentary basins has drawn increasing atten- tion. Fault analyses in petroleum traps have grown along two distinct and successive lines of thought: (1) fault closures and (2) fault-rock seals. Through most of the last century, geometric closure of fault traps and reservoir seal juxtaposition by faults were the focus of research and industrial application. These research and applications were made as structural geology developed quantitative methods for geometric and kine- matic analyses of sedimentary basins, and plate tectonics offered a unified tool to correlate faults and basins on the basis of the nature of plate boundaries to produce stress.
    [Show full text]
  • Evolution of Extensional Basins and Basin and Range Topography West of Death Valley, California K.V
    TECTONICS, VOL. 8, NO. 3, PAGES453-467, JUNE 1989 EVOLUTION OF EXTENSIONAL BASINS AND BASIN AND RANGE TOPOGRAPHY WEST OF DEATH VALLEY, CALIFORNIA K.V. Hodges,L.W. McKenna,J. Stock •, J. Knapp, L. Page,K. Sternlof, D. Silverberg,G. Wrist2, and J. D. Walker 3 Department of Earth, Atmospheric,and Planetary Sciences,Massachusetts Institute of Technology, Cambridge Abstract. Neogeneextension in the Death Valley system remained active during development of region, SE California, has produced a variety of PanamintValley and, thus, during developmentof sedimentarybasins. Diachronousmovements on an modernBasin and Rangetopography as well. These array of strike-slip and normal fault systemshave results indicate that large-scale extension in the resultedin the uplift andpreservation of olderbasins Death Valley region,accommodated by movementon in modernranges. One of the bestexposed of these low- to moderate-angle normal fault systemsand is the Nova basin on the western flank of the high-angle strike-slipfault systems,is a continuing Panamint Mountains. The Nova basin includes over process. Basin and Range topography in the 2000 m of sedimentaryand volcanicrocks deposited PanamintValley- Death Valley areawas generatedat during denudation of the Panamint Mountains least in part by displacements on low-angle metamorphiccore complex in late Miocene(?)- early detachmentsrather than high-angle normal faults. Pliocenetime. The principalgrowth structure for the basinwas the Emigrant detachment,which initiated andmoved at a low angle. Modern PanamintValley, INTRODUCTION west of the range, developedas a consequenceof Late Pliocene- Recent,kinematically linked move- The fact that topographyin the Basin and Range ment on the right-slip, high-angleHunter Mountain Province of the western United States is controlled fault zone and the low-angle Panamint Valley by normal faulting has been recognizedfor over a detachment.
    [Show full text]
  • Mechanical Stratigraphy Controls Normal Fault Growth and Dimensions, Outer
    1 Mechanical Stratigraphy Controls Normal Fault Growth and Dimensions, Outer 2 Kwanza Basin, Offshore Angola 3 4 David Redpath1*, Christopher A.-L Jackson1, Rebecca E. Bell1 5 Basins Research Group (BRG), Department of Earth Science & Engineering, Imperial 6 College, Prince Consort Road, London, SW7 2BP, UK 7 *Corresponding author: David Redpath ([email protected]) 8 This paper is a non-peer reviewed preprint submitted to EarthArXiv. This preprint has been 9 submitted to AGU Tectonics for consideration for publication. 10 11 12 Key Points: 13 Mechanical stratigraphy and fault interaction control the extent to which faults adhere 14 to displacement-length scaling relationships. 15 Fault growth and displacement-length relationships must be considered in context of 16 local controls to be adequately described. 17 Detailed kinematic analysis on faults developing within the same overall tectono- 18 stratigraphic setting can shed light on the kinematics of blind fault growth. 19 20 21 22 Abstract 23 Fault growth and dimensions are controlled by mechanical stratigraphy on seismic scales. Here 24 we present a detailed analysis of largely blind faults and their kinematics Offshore, Angola; 25 where, salt bodies and mass-transport complexes (MTC) act as mechanically restricting 26 elements to an array of extensional faults. Our study presents mechanically restricted faults 27 whose data fall within the general scatter present in global displacement-length (D-L) scaling 28 datasets, and yet have starkly different fault growth models to those expected using geometric 29 data alone. We show how using displacement-length data to determine fault growth can mask 30 the not insignificant mechanical controls on growth histories in the absence of detailed 31 kinematic analysis.
    [Show full text]
  • Data for Quaternary Faults, Liquefaction Features, and Possible Tectonic Features in the Central and Eastern United States, East of the Rocky Mountain Front
    U.S. Department of the Interior U.S. Geological Survey Data for Quaternary faults, liquefaction features, and possible tectonic features in the Central and Eastern United States, east of the Rocky Mountain front By Anthony J. Crone and Russell L. Wheeler Open-File Report 00-260 This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards nor with the North American Stratigraphic Code. Any use of trade names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. 2000 Contents Abstract........................................................................................................................................1 Introduction..................................................................................................................................2 Strategy for Quaternary fault map and database .......................................................................10 Synopsis of Quaternary faulting and liquefaction features in the Central and Eastern United States..........................................................................................................................................14 Overview of Quaternary faults and liquefaction features.......................................................14 Discussion...............................................................................................................................15 Summary.................................................................................................................................18
    [Show full text]
  • Relationship Between Growth Faults, Subsidence, and Land Loss: an Example from Cameron Parish, Southwestern Louisiana, USA
    See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/340069701 Relationship between Growth Faults, Subsidence, and Land Loss: An Example from Cameron Parish, Southwestern Louisiana, USA Article in Journal of Coastal Research · March 2020 DOI: 10.2112/JCOASTRES-D-19-00108.1 CITATION READS 1 257 1 author: Raphael Gottardi University of Louisiana at Lafayette 41 PUBLICATIONS 136 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Basin Analysis View project All content following this page was uploaded by Raphael Gottardi on 23 March 2020. The user has requested enhancement of the downloaded file. Journal of Coastal Research 00 0 000–000 Coconut Creek, Florida Month 0000 Relationship between Growth Faults, Subsidence, and Land Loss: An Example from Cameron Parish, Southwestern Louisiana, USA Matthew O’Leary and Raphael Gottardi* School of Geosciences University of Louisiana at Lafayette Lafayette, LA 70504, U.S.A. ABSTRACT O’Leary, M. and Gottardi, R., 0000. Relationship between growth faults, subsidence, and land loss: An example from Cameron Parish, Southwestern Louisiana, USA. Journal of Coastal Research, 00(0), 000–000. Coconut Creek (Florida), ISSN 0749-0208. This study investigates the relationship between faulting, subsidence, and land loss in coastal Louisiana. A methodology that integrates three-dimensional (3D) seismic data, well logs, high-resolution topographic mapping (LIDAR), and historical aerial photography is successfully developed to identify fault-related geomorphic changes in southwestern Louisiana’s Chenier Plain. Analysis of a 3D seismic survey and well logs reveals the presence of 10 normal faults that form an east-west graben in the middle of the study area.
    [Show full text]
  • Integrating 3-D Seismic Data with Shallow High Resolution Seismic Data
    University of New Orleans ScholarWorks@UNO University of New Orleans Theses and Dissertations Dissertations and Theses Spring 5-19-2017 Evidence of fault movement during the Holocene in Southern Louisiana: integrating 3-D seismic data with shallow high resolution seismic data Joseph P. Frank University of New Orleans, [email protected] Follow this and additional works at: https://scholarworks.uno.edu/td Part of the Geology Commons Recommended Citation Frank, Joseph P., "Evidence of fault movement during the Holocene in Southern Louisiana: integrating 3-D seismic data with shallow high resolution seismic data" (2017). University of New Orleans Theses and Dissertations. 2321. https://scholarworks.uno.edu/td/2321 This Thesis is protected by copyright and/or related rights. It has been brought to you by ScholarWorks@UNO with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights- holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/or on the work itself. This Thesis has been accepted for inclusion in University of New Orleans Theses and Dissertations by an authorized administrator of ScholarWorks@UNO. For more information, please contact [email protected]. Evidence of fault movement during the Holocene in Southern Louisiana: integrating 3-D seismic data with shallow high resolution seismic data A Thesis Submitted to the Graduate Faculty of the University of New Orleans in partial fulfillment of the requirements for the degree of Master of Science in Earth and Environmental Sciences Coastal Geology by Joseph Frank B.S.
    [Show full text]
  • Where Does the Damage Zone Start and Stop?
    Fault zone architecture and its scaling laws: where does the damage zone start and stop? A. TORABI1*, T. S. S. ELLINGSEN1,2, M. U. JOHANNESSEN1,2, B. ALAEI3, A. ROTEVATN2 & D. CHIARELLA4 1NORCE Norwegian Research Centre, Nygaardsgaten 112, 5008 Bergen, Norway 2Department of Earth Science, University of Bergen, PO Box 7800, 5020 Bergen, Norway 3Earth Science Analytics AS, Professor Olav Hanssens vei 7A, 4021 Stavanger, Norway 4Department of Earth Sciences, Royal Holloway, University of London, Egham Hill, Egham TW20 0EX, UK AT, 0000-0001-5685-808X; AR, 0000-0002-8413-3294; DC, 0000-0003-2482-0081 *Correspondence: [email protected] Abstract: Damage zones of different fault types are investigated in siliciclastics (Utah, USA), carbonates (Majella Mountain, Italy) and metamorphic rocks (western Norway). The study was conducted taking measure- ments of deformation features such as fractures and deformation bands on multiple 1D scanlines along fault walls. The resulting datasets are used to plot the frequency distribution of deformation features and to constrain the geometrical width of the damage zone for the studied faults. The damage-zone width of a single fault is con- strained by identifying the changes in the slope of cumulative plots made on the frequency data. The cumulative plot further shows high deformation frequency by a steep slope (inner damage zone) and less deformation as a gentle slope (outer damage zone). Statistical distributions of displacement and damage-zone width and their relationship are improved, and show two-slope power-law distributions with a break point at c. 100 m displace- ment. Bleached sandstones in the studied siliciclastic rocks of Utah are associated with a higher frequency of deformation bands and a wider damage zone compared to the unbleached zone of similar lithology.
    [Show full text]
  • Early Stage Evolution of Growth Faults: 3D Seismic Insights from the Levant Basin, Eastern Mediterranean Journal of Structural G
    Journal of Structural Geology 30 (2008) 888–898 Contents lists available at ScienceDirect Journal of Structural Geology journal homepage: www.elsevier.com/locate/jsg Early stage evolution of growth faults: 3D seismic insights from the Levant Basin, Eastern Mediterranean Catherine Baudon*, Joe Cartwright 3D Lab, School of Earth, Ocean and Planetary Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK article info abstract Article history: The geometry and kinematic evolution of small growth faults were analysed from a high-resolution 3D Received 12 March 2007 seismic dataset located at the margins of the Levant Basin, in the eastern Mediterranean. The 3D Received in revised form 22 February 2008 geometry, segmentation history and throw distribution of one particular fault was reconstructed to Accepted 26 February 2008 evaluate and illustrate the changes in dimension and displacement distribution that occurred during the Available online 8 March 2008 transition from purely blind propagation to propagation at the free surface. The fault is considered to have grown by blind radial propagation of three main segments that hard-linked prior to surface Keywords: interaction. The fault subsequently reached the seabed and continued to accrue displacement as a syn- Growth fault sedimentary fault. Most of the fault surface area formed during the blind propagation phase, but most of Blind propagation Throw distribution the displacement was added during the syn-sedimentary phase of the growth history with little increase Fault nucleation in surface area. The interaction of the fault with the free surface led to a change in the position of the Segmentation point of maximum displacement as well as modifying the vertical throw distribution.
    [Show full text]
  • Deformation Mechanism and Vertical Sealing Capacity of Fault in the Mudstone Caprock
    Journal of Earth Science, Vol. 30, No. 2, p. 367–375, April 2019 ISSN 1674-487X Printed in China https://doi.org/10.1007/s12583-018-0998-7 Deformation Mechanism and Vertical Sealing Capacity of Fault in the Mudstone Caprock Xiaofei Fu 1, 2, 3, Lingyu Yan1, 2, 3, Lingdong Meng *1, 2, 3, Xiaobo Liu *4, 5 1. Laboratory of CNPC Fault-Controlling Reservoir, Northeast Petroleum University, Daqing 163318, China 2. Science and Technology Innovation Team in Heilongjiang Province “Fault Deformation, Sealing and Fluid Migration” Northeast Petroleum University, Daqing 163318, China 3. State Key Laboratory Base of Unconventional Oil and Gas Accumulation and Exploitation, Northeast Petroleum University, Daqing 163318, China 4. School of Energy Resource, China University of Geosciences, Beijing 100083, China 5. Daqing Yushulin Oilfield Development Co. Ltd., Daqing 163453, China Xiaofei Fu: https://orcid.org/0000-0003-3079-7033; Lingdong Meng: https://orcid.org/0000-0002-3712-9153; Xiaobo Liu: https://orcid.org/0000-0002-8613-9323 ABSTRACT: The petrophysical property of mudstone often transforms from ductile to brittle in the process of burial-uplift. The deformation mechanism of fault in brittle and ductile mudstone caprock is different, which leads to the formation of different types of fault zone structure. Different methods are required to evaluate the sealing mechanism of those fault zones. Based on the caprock deformation mech- anism, fault sealing mechanism, quantitative evaluation method of vertical fault sealing capacity is put forward in this study. Clay smear is formed in the process of plastic deformation and its continuity con- trols the sealing capacity of fault.
    [Show full text]
  • MMS 87-0030 – Geologic Report for the St. George Planning Area
    OCS Report MMS 87-0030 Geologic Report for the St. George Basin Planning Area, Bering Sea, Alaska C. DREW COMER BRUCE M. HERMAN SUSAN A. ZERWICK United States Department of the Interior Minerals Management Service Alaska OCS Region Anchorage, Alaska Any use of trade names is for descriptive purposes only and does not constitute endorsement of these products by Minerals Management Service. Contents Introduction......................................... 3 Chapter 1. Regional Geology ..................................... 9 Stratigraphy ....................................... 9 Mesozoic ......................................... 9 Cenozoic ......................................... 13 Structural Setting ................................. 24 Acoustic Basement .................................. 33 Geologic History ................................. 47 Chapter 2 . Petroleum Geology .................................... 51 Reservoir Rock Potential ........................... 51 Source Rock Potential .............................. 56 Potential at the COST Wells ...................... 56 Organic Carbon ................................. 56 Kerogen Type ................................... 56 Thermal Maturation ............................. 58 Potential in Other Areas ......................... 58 Traps and the Timing of Oil Migration .............. 61 Exploration History ................................ 63 Exxon Wells ........................................ 63 Chapter 3 . Environmental Geology ................................ 67 Near-Surface Sediments
    [Show full text]
  • Fault Geometry and Kinematics Within the Terror Rift, Antarctica THESIS
    Fault Geometry and Kinematics within the Terror Rift, Antarctica THESIS Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By William B. Blocher Graduate Program in Earth Sciences The Ohio State University 2017 Master's Examination Committee: Dr. Terry Wilson, Advisor Dr. Thomas Darrah Dr. Derek Sawyer Copyrighted by William B. Blocher 2017 Abstract The Terror Rift is the youngest expression of the intraplate West Antarctic Rift System that divides the Antarctic continent. Previous studies of the Terror Rift have ascribed a variety of interpretations to its structure, and especially to the regional anticline known as the Lee Arch, which has been explained as a transtensional flower structure, a rollover anticline, and as the result of magmatic inflation. Fault mapping and the documentation of stratal dips in this study have revealed a Terror Rift structure characterized by north-south folds and a complex distribution of faults. Nearly all faults have normal sense dip separation. A continuous zone of west-dipping faults with relatively high-magnitude normal separation are interpreted to be the border fault system defining the eastern margin of Terror Rift. Reconstruction of listric ramp-flat geometry of this border fault system explains intrarift fold and fault patterns well. Zonation of structures indicates that the listric rift detachment faults are segmented along the rift axis. This new model for rift structure indicates orthogonal rift extension in the ENE- WSW direction, with low strains of <10% calculated from bed-length balancing. i Acknowledgments To my advisor, Dr.
    [Show full text]
  • Controls on Structural Styles and Decoupling in Stratigraphic Sequences
    Manuscript submitted to Journal of Structural Geoloy 1 Controls on structural styles and decoupling in stratigraphic sequences 2 with double décollements during thin-skinned contractional tectonics: 3 insights from numerical modelling 4 Qingfeng Meng*1, David Hodgetts 5 School of Earth and Environmental Sciences, University of Manchester, M13 9PL, UK 6 Abstract 7 Six series of particle-based numerical experiments were performed to simulate thin-skinned 8 contractional tectonics in stratigraphic sequences with double décollements during horizontal 9 shortening. The models were assigned with varying rock competence, depth and thickness of the 10 upper décollement, which resulted in significantly different styles of deformation and decoupling 11 characteristics above and below the upper décollement. The models composed of the least 12 competent material produced distributed sinusoidal detachment folds, with many shallow 13 structures profoundly decoupled from the deep-seated folds. The models composed of a more 14 competent material are dominated by faulted, diapir-cored box folds, with minor disharmonic folds 15 developed in their limbs. Differently, the results of models composed of the most competent 16 material are characterised by localised piggyback thrusts, fault-bend folds and pop-up structures 17 with tensile fractures developed in fold hinges. Depth of the upper décollements also plays an 18 important role in controlling structural decoupling, i.e. the shallower the upper décollements, the 19 higher the degree of decoupling becomes. Thicker upper décollements can provide sufficient 20 mobile materials to fill fold cores, and contribute to the formation of secondary disharmonic folds, 21 helping enhance structural decoupling. Our modelling results are comparable to the structural 1 *Corresponding author.
    [Show full text]