Outward drainage => Starved basin Lithosphere stretching Axial lake (restricted) ⇒M.O. Figure 1.2.1 shows an idealized passive margin. The down-dropped basin formed during rifting because of stretching and thinning of the continental crust. Some mechanisms for earlier graben type subsidence and later regional downsagging of shelf and slope at passive continental margins are reviewed. 6.2) that explain many aspects of … Figure 1(a) Simplified cross section illustrating the kinematic domains and structural styles in a typical passive margin salt basin (modified after Rowan et al., 2004; Brun and Fort, 2011). The continental margins are one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The crustal structure of the Santos Basin shows a zonation from west to east of alternating bands of NE-SW-trending thin (plastic basement terrains) and thick (resistant basement terrains) stretched continental crust. Necking of continental crust? The overall model setup shares the characteristics of earlier studies aiming to understand kinematic domain partition and evolution in passive margin salt basins (Fig. Despite, or perhaps because of this, there is still much to learn about the variety of hydrocarbon habitats they present. Passive‐margin salt basins are classified as prerift, syn‐stretching, syn‐thinning, and syn‐exhumation. These facies occur within a thick (> 10,000 ft) prograded wedge of shelf sediments in this passive margin basin. the West African Passive Margin (Brice and other, 1980; and Brice and Pardo, 19801, and the Recon- cavo Basin of Eastern Brazil (Chignone and E Andrade, 1970). While production in these basins is mainly from Early Cretaceous fluvial-deltaic sandstones and non-marine carbonates flanking the margins of the basin… S. Rawat , Sachchanand, Dr Alok Dave, Shipra S. … Quartz and feldspars with amphibole, epidote, garnet, staurolite, and kyanite are derived from crystalline basements exposed at the core of ancient orogens and cratonic blocks (dissected continental block provenance). Figure 8) passive margin. The continental margins are the zone of the ocean floor that separate the thin oceanic crust from thick continental crust. The Angola Basin is located along the West African South Atlantic Margin which extends from Cameroon to Angola. 1992 – cited in Allen and Allen 2005 Following Salveson (1978), the evolution of passive margins can be broken into five stages (Fig. The east coast of the United States is a good example; the plate boundary is located along the mid Atlantic ridge, far from the coast. Correlation of facies from hydrocarbon-bearing continental and transitional marine sandstones to time-equivalent high-energy shelf-margin carbonates provide insight into hydrocarbon habitats of the Baltimore Canyon basin. Active and Passive Continental Margins. A passive margin is the transition between oceanic and continental lithosphere that is not an active plate margin.A passive margin forms by sedimentation above an ancient rift, now marked by transitional lithosphere.Continental rifting creates new ocean basins. Passive margin basins • The initial stage of a true oceanic basin setting (or a proto-oceanic rift system) is established when two divergent continents separate and new oceanic crust forms in the intervening space. Rift basin. Passive margin basin. A passive continental margin occurs where the transition from land to sea is not associated with a plate boundary. The tectonic evolution of Laxmi basin, presently located along western Indian passive margin, remains debated. In vertical section this Unfortunately, the model's predictions have largely been misunderstood. East coast of North America Radha Krishan, Priyanka Bhardwaj, C.P. Eventually the continental rift forms a mid-ocean ridge and the locus of extension moves away from the continent-ocean boundary. Basin margin concept The response of the depositional systems to this fall in relative sea level depends on the nature of the basin margins. Passive margins are less geologically active. 2) (e.g. Passive margins are traditionally regarded as tectonically quiescent, however the increasing recognition of significant post-rift tectonic uplift alon… Prerift salt, such as the Triassic Keuper in the Western Pyrenees, undergoes thick‐skinned extension, first decoupled and then coupled, along with its substrate and cover. 9. o Shelf-break margins o Ramp margins o Rift margins o Foreland basin margins o Growth –fault margins. The second stage leads to the formation of an oceanic basin, similar to the modern Red Sea. Modern Passive Continental Margin Continental Rift. Campos & Santos Basins – Demercian et al. This does not necessarily mean that such a basin … Purchase Regional Geology and Tectonics: Phanerozoic Passive Margins, Cratonic Basins and Global Tectonic Maps - 1st Edition. Passive margins are found at every ocean and continent boundary that is not marked by a strike-slip fault or a subduction zone. Passive continental margins abutting the Atlantic Ocean and Gulf of Mexico developed as a large... New Ocean Basin. Stage « rift » Syntectonic sedim. 1993). Salt basins on passive margins are typically classified as prerift, synrift, or postrift (e.g. There is no evidence for seaward-dipping reflector (SDR) sequences often associated with volcanic margins or intracrustal and Moho reflection events beneath the basement reflection, nor is there evidence of salt layers and associated structures similar to those observed along the passive margins of southern Brazil (e.g. Prevailing geodynamic models of Laxmi basin … PASSIVE MARGINS AND RIFT BASINS Atlantic-type margins and back-arc basins basically form by crustal extension and formation of an oceanic basin. A. 10. Rift valleys formed as the thick continental crust (orange) ripped apart and thined. USA, Canada, Iraq, Iran, Pakistan, & India (Upper Assam basin). Passive-margin sands have two first-cycle sources. in this type of basin e.g. Sequence stratigraphic study of Passive Margin and Foreland sequences and impact of post Barail tectonics on the structurisation and hydrocarbon potential of Geleki and satellite fields of Upper Assam. Problem: a typical rift zone is about 50 km wide, thus transition zone at a continental margin would be only 25 km wide. Print Book & E-Book. ISBN 9780444563576, 9780444563620 South Atlantic, passive continental margin basin, prototype basin, basin evolution, hydrocarbon accumulation, giant oil and gas fields Introduction Passive continental margin basins have been confirmed to have the most abundant oil and gas resources, 304 out of 877 giant oil and gas fields with 2P recoverable reserves of Subsidence along a passive margin, mostly due to long-term accumulation of sediments on the continental shelf. The continental margins are the shallow water areas found in proximity to continents. 6 Basin Classification Passive Margins Strongly attenuated continental crust Stretched over distances of 50-500 km Overlain by seaward-thickening sediment prisms Typically shallow-marine deposits Sometimes referred to as “Atlantic-type margins” or “continental rises and terraces” (Boggs) Beaumont et al. (2) The architecture of these basins and the basin fill are strongly influenced by the displacement geometry on the bounding normal fault systems (e.g., Gibson et al., 1989). Passive margins have been the reliable, accessible mainstay of exploration success worldwide for the last 25 years, and have hosted the spectacularly fast exploitation of deepwater resources (Angola, Nigeria, Brazil, Trinidad, USA Gulf of Mexico, Egypt, Australia and India). Large drainage basin systems. Syn-rift units include shales, sandstones, and breccias of Early Jurassic age. Fig. This paper systematically investigates and compares the petroleum geology elements and oil and gas exploration potential in the deep-water basins along the conjugate passive margins between Morocco in NW Africa and Nova Scotia in Canada. Then, as the ocean basin forms the passive continental margin will gradually subside. East Africa Rift . It is characterized as a passive margin that began spreading in the south and then continued upwards throughout the basin. Summary: types of rift basins and passive margins; Factors affecting hydrocarbon potential of rift basins and passive margins, including Jeanne d’Arc rift basin of ENAM margin ; Blue Sac field site – Views of youngest syn-rift strata and inversion-related structures. The reasons for this interest include: (1) Rift basins are found on all passive (Atlantic-type) continental margins and provide a record of the early stages of (super)continental breakup. The treatment of passive margin sedimentation in this model is much more sophisticated than anything you will see in the complicated basin evolution models produced by the geophysics community. The eastern North American passive margin includes the Atlantic continental margin from the Bahamas to Baffin Bay. (b) Regional interpreted seismic profile crossing the Lower Congo Basin (modified after Marton et al., 2000).Note the minibasins and diapirs in the mid-slope. The petroleum accumulations in passive margin basins (pericratonic rifts or sag basins) of the partially subducted continent may escape from under thrusting or may be preserved under brow zone of thrust belt of obducting continent. Introduction. Mature Ocean Basin. Some 50 major river drainage systems drain most of the land surface of the present-day continents and of these about half drain to modern passive margins, giving the thermal blanketing, reservoir and seal for recent hydrocarbon generation and preservation. ... Dong-ning Zhang, On the Dynamics of Extensional Basin, Mechanics Problems in Geodynamics Part I, 10.1007/978-3-0348-9065-6, (579-603), (1995). 6. Adam et al., 2012a; Brun and Fort, 2004; Fort et al., 2004a).