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Showing 1 to 20 of 48 for “"Passive margin"”.
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Geology of the passive margin off New England
… to reconstruct the geologic history of the passive continental margin off New England. Rifting between northeastern North America and Morocco during the Middle-Late Triassic produced a complex series of horsts and grabens in Precambrian/Paleozoic crust. Intra-rift sediments consist of …
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Continental Deformation: Collisional Orogenesis to Passive Margin Processes
… the Wilson cycle, intracontinental collision and passive margin development. I present a map of NW Nepal river channel steepness (ksn), a proxy for rock uplift rate over 103-105 years, coupled with a seismotectonic model, and then expand this map and accompanying model to the entire Himalaya; and …
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Geology of the passive margin off New England
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1979.
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Influence of spatially variable precipitation on passive margin escarpment evolution
Passive margin escarpments are large-scale geomorphic features which persist over timescales of tens of millions of years. The maintenance of steep topography over these timescales challenges conventional understanding of fluvial erosion. Typical explanations for passive margin escarpments rely on …
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The post-breakup evolution of the western Indian high-elevation passive margin
… development of the Western Indian high-elevation passive margin is complex. At least two major rifting events (India/Madagascar and India/Seychelles) and a major hotspot (The Reunion plume) are believed to have been instrumental in the formation and development of the margin. However, the temporal …
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Constraints on passive margin escarpment evolution from river basin reorganization in Brazil
Escarpments are present on passive margins around the world, but their evolution is poorly understood. Some geologists interpret escarpments as stationary features, whereas others have argued that they are retreating inland faster than a kilometer per Myr. I investigate Brazilian escarpments by …
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Evolution of early Proterozoic passive-margin carbonate platform, Rocknest Formation, Wopmay Orogen, N.W.T., Canada
… Canada, is an early Proterozoic (l.B9 Ga) passivemargin carbonate platform. It is an eastward-thinning prism, 0 to 1,100 m thick, extending for over 220 km parallel to strike, and over 200 k.m perpendicular to strike. It contains from west to east, slope, outer-shelf, shoaloomplex, and …
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Jurassic-Recent Structure, Stratigraphy, and Basin Modeling of the Rifted-Passive Margin of Southern Morocco
… southern part of the Moroccan Atlantic rifted-passive margin. Oblique rifting with its conjugate margin in eastern Canada started at the Late Triassic-Early Jurassic by splitting of the northeast, structural grain inherited from the late Paleozoic, Appalachian-Atlas orogeny. A massive, …
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Deep-marine depositional systems of the western North Atlantic: Insights into climate and passive-margin evolution
… deposits in deep-marine settings, particularly passive margins, provide a unique, long-term record of paleoclimate, paleoceanography, and tectonics affecting the basin in question. Whereas deep-marine strata may be used to answer myriad of questions regarding the evolution and development of …
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The Durness Group of NW Scotland: a stratigraphical and sedimentological study of a Cambro-Ordovician passive margin succession
… was deposited on the Scottish sector of the passively-subsiding, continental margin of the Laurentian craton, and now forms part of the Hebridean terrane, lying to the west of the Moine Thrust zone. It represents c. 920 m of shallow marine, peritidal carbonates with minor siliciclastic and …
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Gravity Modeling, Seismic Stratigraphy, and Thermal Maturity Modeling of Hydrocarbons of the Permian Foreland Basin, USA, and the Sergipe-Alagoas Rifted-Passive Margin, Brazil
… crust, and 3) the outer domain. The conjugate margin in northern Gabon, west Africa is wider with greater stretching and is explained by Precambrian basement fabrics that were oriented in a near-orthogonal to continental rifting. In Chapter 5, I used 2D seismic and well logs to define four …
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Sedimentology and tectonic implications of the Late Proterozoic to Early Cambrian Chilhowee Group in southern and central Virginia
Few detailed facies analyses of rift to passive-margin transitions have been undertaken in exhumed orogenic belts. In the central Appalachians, the Chilhowee Group records such an evolution. The Unicoi and basal Hampton Formations record the transition from rifting to opening of the Iapetus Ocean. …
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Contractional tectonics : the Himalayan orogen and Perdido fold-thrust belt
… collisional orogenic belts and toe structures of passive margins, which are characterized by fold-thrust belts that are hundreds of kilometer-scale and tens of kilometer-scale, respectively. The Himalayan orogen is an excellent example of collisional orogenic belts along convergent plate …
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Lithologic Controls on Bedrock Channel Morphology in the Buffalo River Basin
<p>The longevity of high relief terrains in passive margin systems remains an explained phenomenon in geomorphology. Current landscape evolution models assume an equilibrium state between rock uplift rates and erosion rates. However, analysis of chi gradients of bedrock channels across several …
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A quantitative approach to the evolution of the central Walvis Basin offshore NW-Namibia : structure, mass balancing, and hydrocarbon potential
… of the South Atlantic and its conjugated pair of passive continental margins. The Walvis Basin offshore NW-Namibia is an Early Cretaceous to recent depositional centre with a typically wedge-shaped postrift sedimentary succession covering an area of 105000km2. A 2D model transect across the …
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Oroclines of the Iberian Variscan belt: Tectonic and paleogeographic implications
… Quartzite of the deformed Iberian Paleozoic passive margin sequence confirm the existence of the so-called Central Iberian orocline. Structural continuity between the Cantabrian and Central Iberian oroclines suggests that they formed contemporaneously and in the same fashion. Mesoscale …
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Post-Orogenic Exhumation and Glacial Erosion on the Flanks of the North Atlantic
Many passive margins experience pulsed exhumation events late in their history as a result of plate boundary distal geodynamic mechanisms or climatic events. The onset of late Cenozoic glaciation, often associated with enhanced rates of erosion, is one such possible cause of passive margin …
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Early and Middle Atokan Lithostratigraphy and Reservoir Development, Northern Arkoma Basin, Northwestern Arkansas
… in the shallow subsurface at the northern margin of the Arkoma Basin in northwestern Arkansas. Sedimentary units of this time interval reflect basinal subsidence, and the transition of the Arkoma Basin from a passive margin shelf to a rapidly evolving foreland arc basin. Sediment sources …
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THE SEDIMENT AND CRUSTAL STRUCTURE OF THE SOUTHEASTERN UNITED STATES
… billions of years. Currently the SEUS lies on a passive margin far away from ongoing tectonics, yet retains the ability to produce damaging earthquakes. It has long been suspected that the current seismicity in the SEUS is related to zones of weakness inherited from past structural boundaries; …
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