Reconstructing the Himalayan margin prior to collision with Asia: Proterozoic and lower Paleozoic geology and its implications for Cenozoic tectonics
Published:October 08, 2019
P. M. Myrow, N. C. Hughes, N. R. McKenzie, 2019. "Reconstructing the Himalayan margin prior to collision with Asia: Proterozoic and lower Paleozoic geology and its implications for Cenozoic tectonics", Himalayan Tectonics: A Modern Synthesis, P. J. Treloar, M. P. Searle
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Reconstructing the stratigraphic architecture of deposits prior to Cenozoic Himalayan uplift is critical for unravelling the structural, metamorphic, depositional and erosional history of the orogen. The nature and distribution of Proterozoic and lower Paleozoic strata have helped elucidate the relationship between lithotectonic zones, as well as the geometries of major bounding faults. Stratigraphic and geochronological work has revealed a uniform and widespread pattern of Paleoproterozoic strata >1.6 Ga that are unconformably overlain by <1.1 Ga rocks. The overlying Neoproterozoic strata record marine sedimentation, including a Cryogenian diamictite, a well-developed carbonate platform succession and condensed fossiliferous Precambrian–Cambrian boundary strata. Palaeontological study of Cambrian units permits correlation from the Indian craton through three Himalayan lithotectonic zones to a precision of within a few million years. Detailed sedimentological and stratigraphic analysis shows the differentiation of a proximal realm of relatively condensed, nearshore, evaporite-rich units to the south and a distal realm of thick, deltaic deposits to the north. Thus, Neoproterozoic and Cambrian strata blanketed the northern Indian craton with an extensive, northward-deepening, succession. Today, these rocks are absent from parts of the inner Lesser Himalaya, and the uplift and erosion of these proximal facies explains a marked change in global seawater isotopic chemistry at 16 Ma.
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Himalayan Tectonics: A Modern Synthesis
CONTAINS OPEN ACCESS
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.