Structural Evolution of the Central Nepal Fold-thrust Belt and Regional Tectonic and Structural Significance of the Ramgarh Thrust (PHD). PDF Download

Author: Ofori Pearson
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Author: S. Mukherjee
Publisher: Geological Society of London
ISBN: 1862397031
Category : Science
Languages : en
Pages : 325

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Book Description
The Himalayan mountain belt, which developed during the India–Asia collision starting about 55 Ma ago, is a dramatically active orogen and it is regarded as the classic collisional orogen. It is characterized by an impressively continuous 2500 km of tectonic units, thrusts and normal faults, as well as large volumes of high-grade metamorphic rocks and granites exposed at the surface. This constitutes an invaluable field laboratory, where amazing crustal sections can be observed directly in very deep gorges. It is possible to unravel the tectonic and metamorphic evolution of litho-units, to observe the mechanisms of exhumation of deep-seated rocks and the propagation of the deformation. Himalayan tectonics has been the target of many studies from numerous international researchers over the years. In the last 15 years there has been an explosion of data and theories from both geological and geophysical perspectives. This book presents the results of integrated multidisciplinary studies, including geology, petrology, magmatism, geochemistry, geochronology and geophysics, of the structures and processes affecting the continental lithosphere. These processes and their spatial and temporal evolution have major consequences on the geometry and kinematics of the India–Eurasia collision zone.

Author: Richard D. Law
Publisher: Geological Society of London
ISBN: 9781862392090
Category : Science
Languages : en
Pages : 638

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Book Description
This volume includes sections on: Evolution of ideas on channel flow and ductile extrusion in the Himalaya-Tibetan Plateau system; Modeling channel flow and ductile extrusion processes; Geological constraints on channel flow and ductile extrusion as an important orogenic process in the Himalaya-Tibetan Plateau, the Hellenides and Appalachians, and the Canadian Cordillera.

Author: P.J. Treloar
Publisher: Geological Society of London
ISBN: 1786204053
Category : Science
Languages : en
Pages : 674

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Book Description
The Himalaya–Karakoram–Tibet mountain belt resulted from Cenozoic collision of India and Asia and is frequently used as the type example of a continental collision orogenic belt. The last quarter of a century has seen the publication of a remarkably detailed dataset relevant to the evolution of this belt. Detailed fieldwork backed up by state-of-the-art structural analysis, geochemistry, mineral chemistry, igneous and metamorphic petrology, isotope chemistry, sedimentology and geophysics produced a wide-ranging archive of data-rich scientific papers. The rationale for this book is to provide a coherent overview of these datasets in addressing the evolution of the mountain ranges we see today. This volume comprises 21 specially invited review papers on the Himalaya, Kohistan arc, Tibet, the Karakoram and Pamir ranges. These papers span the history of Himalayan research, chronology of the collision, stratigraphy, magmatic and metamorphic processes, structural geology and tectonics, seismicity, geophysics, and the evolution of the Indian monsoon. This landmark set of papers should underpin the next 25 years of Himalayan research.

Author: P.G. DeCelles
Publisher: Geological Society of America
ISBN: 081372547X
Category : Science
Languages : en
Pages : 77

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"Spanning eight kilometers of topographic relief, the Himalayan fold-thrust belt in Nepal has accommodated more than 700 km of Cenozoic convergence between the Indian subcontinent and Asia. Rapid tectonic shortening and erosion in a monsoonal climate have exhumed greenschist to upper amphibolite facies rocks along with unmetamorphosed rocks, including a 5-6-km-thick Cenozoic foreland basin sequence. This Special Paper presents new geochronology, multisystem thermochronology, structural geology, and geological mapping of an approximately 37,000 km2 region in midwestern and western Nepal. This work informs enduring Himalayan debates, including how and where to map the Main Central thrust, the geometry of the seismically active basal Himalayan detachment, processes of tectonic shortening in the context of postcollisional India-Asia convergence, and long-term geodynamics of the orogenic wedge"--Publisher's website

Author: J. Poblet
Publisher: Geological Society of London
ISBN: 9781862393202
Category : Folds (Geology).
Languages : en
Pages : 266

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Book Description
Fold-and-thrust belts occur worldwide, have formed in all eras of geological time, and are widely recognized as the most common mode in which the crust accommodates shortening. Much current research on the structure of fold-and-thrust belts is focused on structural studies of regions or individual structures and on the geometry and evolution of these regions employing kinematic, mechanical and experimental modelling. In keeping with the main trends of current research, this title is devoted to the kinematic evolution and structural styles of a number of fold-and-thrust belts formed from palaeozoic to recent times. The papers included in this book cover a broad range of different topics, from modelling approaches to predict internal deformation of single structures, 3D reconstructions to decipher the structural evolution of groups of structures, palaeomagnetic studies of portions of fold-and-thrust belts, geometrical and kinematical aspects of Coulomb thrust wedges and structural analyses of fold-and-thrust belts to unravel their sequence of deformations--

Author: J.A. Hammerstein
Publisher: Geological Society of London
ISBN: 1786204479
Category : Science
Languages : en
Pages : 455

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Book Description
The outer parts of collision mountain belts are commonly represented by fold and thrust belts. Major advances in understanding these tectonic settings have arisen from regional studies that integrate diverse geological information in quests to find and produce hydrocarbons. Drilling has provided tests of subsurface forecasts, challenging interpretation strategies and structural models. This volume contains 19 papers that illustrate a diversity of methods and approaches together with case studies from Europe, the Middle East and the Asia-Pacific region. Collectively they show that appreciating diversity is key for developing better interpretations of complex geological structures in the subsurface – endeavours that span applications beyond the development of hydrocarbons.

Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 664

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Author: Gang Rao
Publisher: Frontiers Media SA
ISBN: 2889742342
Category : Science
Languages : en
Pages : 387

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Book Description

Author: Subodha Khanal
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 202

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Book Description
Over the last two decades, several competing dynamic models have been proposed to explain the kinematics of the Himalayan thrust belt. The accuracy of dynamic and kinematic models is limited by poorly documented geologic structures. With increased accessibility of the thrust belt and advances in analytical techniques, several new data sets greatly improve our understanding and provide a background to reevaluate the kinematics of the Himalayan thrust belt. In this dissertation, I integrate structural mapping, microstructural analysis, detrital and igneous zircon geochronology, low-temperature thermochronology, Nd isotopic analysis, and structural reconstructions in central Nepal to determine the evolution of the Himalayan thrust belt. Because the role and evolution of the Main Central thrust, the Ramgarh-Munsiari thrust, and the Lesser Himalayan duplex are highly debated, I emphasize these systems to provide a comprehensive structural evolution of the Himalayan thrust belt. U-Pb dating of metamorphic rims of igneous zircons and crystallization ages of cross-cutting pegmatite veins suggest that deformation on the Himalayan thrust belt started with slip on an intra-Greater Himalayan thrust active at ~20-29 Ma that emplaced the now erosionally isolated Kathmandu klippe. These ages predate the slip on the Main Central thrust. Absence of a fault contact between the Greater Himalaya and Tethyan Himalaya in the klippe suggests the South Tibetan Detachment system may have activated after the slip started on the intra-Greater Himalayan thrust. Ductile motion on the South Tibetan Detachment system may have ended prior to the activation of the Main Central thrust. This result and observations contradict the extrusion model that advocates contemporaneous activity with thrust sense shear on the Main Central thrust and normal sense shear on the South Tibetan Detachment system. In addition, there is another orogenic scale thrust, subparallel to the Main Central thrust, the Ramgarh-Munsiari thrust, that only carries lower Lesser Himalayan Paleoproterozoic rock over other Lesser Himalayan rock and accommodates a magnitude of shortening similar to the 100's km of slip on the Main Central thrust. I construct an orogenic scale balanced cross-section along the Marsyangdi River where the entire Lesser Himalayan duplex is exposed, particularly focusing on the architecture of the duplex to determine whether the duplex is forward dipping or hinterland dipping and the presence/absence of an orogenic scale, out-of-sequence thrust. I integrate quartz-feldspar deformation temperatures and zircon (U-Th)/He thermochronology and present a kinematic model that provides the structural context for geophysical, petrological, and geochronological studies in central Nepal. Collectively, this study helps to determine partitioning of strain among the various thrust sheets that account for over 2000 km of shortening in a compressional continental tectonic setting. The results suggest that deformation in the Himalaya began with the activation of an intra-Greater Himalayan thrust and successively moved south with the activation of Main Central thrust, Ramgarh-Munsairi thrust, Lesser Himalayan duplex, and finally the Subhimalayan thrust system. Although there was minor out-of-sequence thrusting in the hinterland, the bulk of the Himalaya evolved in-sequence thrusting from north to south.