Investigating Parameters of Geomorphic Direct Runoff Hydrograph Models     

Ghumman  A. R.  Ghazaw  Y.  Abdel-Maguid  R. H.  Zafar  A. 《Water Resources》2019,46(1):19-28

Water Resources - Formulation of rainfall runoff models and identification of their parameters is difficult step especially for catchments having scanty or no data. Parameters of geomorphic...  相似文献   

Sediment routing in the Zagros foreland basin: Drainage reorganization and a shift from axial to transverse sediment dispersal in the Kurdistan region of Iraq     

Renas I. Koshnaw  Brian K. Horton  Daniel F. Stockli  Douglas E. Barber  Mazin Y. Tamar-Agha 《Basin Research》2020,32(4):688-715

In the northwestern sector of the Zagros foreland basin, axial fluvial systems initially delivered fine-grained sediments from northwestern source regions into a contiguous basin, and later transverse fluvial systems delivered coarse-grained sediments from northeastern sources into a structurally partitioned basin by fold-thrust deformation. Here we integrate sedimentologic, stratigraphic, palaeomagnetic and geochronologic data from the northwestern Zagros foreland basin to define the Neogene history of deposition and sediment routing in response to progressive advance of the Zagros fold-thrust belt. This study constrains the depositional environments, timing of deposition and provenance of nonmarine clastic deposits of the Injana (Upper Fars), Mukdadiya (Lower Bakhtiari) and Bai-Hasan (Upper Bakhtiari) Formations in the Kurdistan region of Iraq. Sediments of the Injana Formation (~12.4–7.75 Ma) were transported axially (orogen-parallel) from northwest to southeast by meandering and low-sinuosity channel belt system. In contrast, during deposition of the Mukdadiya Formation (~7.75–5 Ma), sediments were delivered transversely (orogen-perpendicular) from northeast to southwest by braided and low-sinuosity channel belt system in distributive fluvial megafans. By ~5 Ma, the northwestern Zagros foreland basin became partitioned by growth of the Mountain Front Flexure and considerable gravel was introduced in localized alluvial fans derived from growing topographic highs. Foredeep accumulation rates during deposition of the Injana, Mukdadiya and Bai-Hasan Formations averaged 350, 400 and 600 m/Myr respectively, suggesting accelerated accommodation generation in a rapidly subsiding basin governed by flexural subsidence. Detrital zircon U-Pb age spectra show that in addition to sources of Mesozoic-Cenozoic cover strata, the Injana Formation was derived chiefly from Palaeozoic-Precambrian (including Carboniferous and latest Neoproterozoic) strata in an axial position to the northwest, likely from the Bitlis-Puturge Massif and broader Eastern Anatolia. In contrast, the Mukdadiya and Bai-Hasan Formations yield distinctive Palaeogene U-Pb age peaks, particularly in the southeastern sector of the study region, consistent with transverse delivery from the arc-related terranes of the Walash and Naopurdan volcano-sedimentary groups (Gaveh-Rud domain?) and Urumieh-Dokhtar magmatic arc to the northeast. These temporal and spatial variations in stratigraphic framework, depositional environments, sediment routing and compositional provenance reveal a major drainage reorganization during Neogene shortening in the Zagros fold-thrust belt. Whereas axial fluvial systems initially dominated the foreland basin during early orogenesis in the Kurdistan region of Iraq, transverse fluvial systems were subsequently established and delivered major sediment volumes to the foreland as a consequence of the abrupt deformation advance and associated topographic growth in the Zagros.  相似文献   

Grain‐scale pressure variations and chemical equilibrium in high‐grade metamorphic rocks     

L. Tajčmanová  Y. Podladchikov  R. Powell  E. Moulas  J.C. Vrijmoed  J.A.D. Connolly 《Journal of Metamorphic Geology》2014,32(2):195-207

In the classical view of metamorphic microstructures, fast viscous relaxation (and so constant pressure) is assumed, with diffusion being the limiting factor in equilibration. This contribution is focused on the only other possible scenario – fast diffusion and slow viscous relaxation – and brings an alternative interpretation of microstructures typical of high‐grade metamorphic rocks. In contrast to the pressure vessel mechanical model applied to pressure variation associated with coesite inclusions in various host minerals, a multi‐anvil mechanical model is proposed in which strong single crystals and weak grain boundaries can maintain pressure variation at geological time‐scales in a polycrystalline material. In such a mechanical context, exsolution lamellae in feldspar are used to show that feldspar can sustain large differential stresses (>10 kbar) at geological time‐scales. Furthermore, it is argued that the existence of grain‐scale pressure gradients combined with diffusional equilibrium may explain chemical zoning preserved in reaction rims. Assuming zero net flux across the microstructure, an equilibrium thermodynamic method is introduced for inferring pressure variation corresponding to the chemical zoning. This new barometric method is applied to plagioclase rims around kyanite in felsic granulite (Bohemian Massif, Czech Republic), yielding a grain‐scale pressure variation of 8 kbar. In this approach, kinetic factors are not invoked to account for mineral composition zoning preserved in rocks metamorphosed at high grade.  相似文献   

Imbalanced magnetohydrodynamic turbulence modified by velocity shear in the solar wind     

G. Gogoberidze  Y. M. Voitenko 《Astrophysics and Space Science》2016,361(11):364

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Observations of Multiple Blobs in Homologous Solar Coronal Jets in Closed Loop     

Q. M. Zhang  H. S. Ji  Y. N. Su 《Solar physics》2016,291(3):859-876

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A new model for charged anisotropic compact star     

S. K. Maurya  M. K. Jasim  Y. K. Gupta  T. T. Smitha 《Astrophysics and Space Science》2016,361(5):163

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Anisotropic generalization of Matese & Whitman solution for compact star models in general relativity     

Baiju Dayanandan  S. K. Maurya  Y. K. Gupta  Smitha T.T. 《Astrophysics and Space Science》2016,361(5):160

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New distances for a selected set of visual binaries with inconsistent dynamical masses     

V. S. Tamazian  O. Y. Malkov  J. A. Docobo  D. A. Chulkov  P. P. Campo 《Astrophysics and Space Science》2016,361(3):105

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From Nearby Low Luminosity AGN to High Redshift Radio Galaxies: Science Interests with Square Kilometre Array     

P. Kharb  D. V. Lal  V. Singh  J. Bagchi  C. H. Ishwara Chandra  A. Hota  C. Konar  Y. Wadadekar  P. Shastri  M. Das  K. Baliyan  B. B. Nath  M. Pandey-Pommier 《Journal of Astrophysics and Astronomy》2016,37(4):34

We present detailed science cases that a large fraction of the Indian AGN community is interested in pursuing with the upcoming Square Kilometre Array (SKA). These interests range from understanding low luminosity active galactic nuclei in the nearby Universe to powerful radio galaxies at high redshifts. Important unresolved science questions in AGN physics are discussed. Ongoing low-frequency surveys with the SKA pathfinder telescope GMRT, are highlighted.  相似文献   

Acoustic and Slow Sausage Oscillations in the Stratified Solar Photosphere: Hinode Observations and Phase Relationships     

Y. T. Tsap  A. V. Stepanov  Y. G. Kopylova 《Solar physics》2016,291(11):3349-3356

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