First-principles simulations of CaO and CaSiO3 liquids: structure,thermodynamics and diffusion     

Suraj K. Bajgain  Dipta B. Ghosh  Bijaya B. Karki 《Physics and Chemistry of Minerals》2015,42(5):393-404

  相似文献   

Coralline algae and benthic foraminifera from the long formation (middle Miocene) of the Little Andaman Island,India: Biofacies analysis,systematics and palaeoenvironmental implications     

Suman Sarkar  Amit K. Ghosh  G. M. Narasimha Rao 《Journal of the Geological Society of India》2016,87(1):69-84

  相似文献   

Sedimentologic attributes of the Proterozoic siliciclastic packages of the Garhwal–Kumaun Lesser Himalaya,India: Implication for their relationship and palaeobasinal conditions     

Sumit K. Ghosh  Poonam Jalal  R. Islam 《Journal of the Geological Society of India》2016,87(6):661-678

The present work addresses the long-standing issues on the characterization aspect of the Proterozoic siliciclastic successions exposed in the central part of the Lesser Himalaya, restricted between the Main Boundary Thrust (MBT) and the Main Central Thrust (MCT). Geologic, sedimentologic, and petrographic study divides the Lesser Himalaya in two zones- northern Palaeo- Mesoproterozoic Inner Lesser Himalayan (ILH) and southern Neoproterozoic Outer Lesser Himalayan (OLH) zones. The major lithofacies recognized from the zones are - (i) coarse grained siliciclastic (CGS), (ii) interbedded medium and fine-grained siliciclastic (IMFS), (iii) argillite (ARG), and (iv) siliciclastic–argillite rhythmites (SAR). Amongst all these facies, the nearshore IMFS facies shows consistent presence in both OLH and ILH zones. From the facies distribution pattern, a northwest–southeasterly trending palaeo- shoreline has been envisaged. The CGS facies in the ILH hints towards an alluvial fan setting during 1.8 Ga rifting phase associated with penecontemporaneous basic magmatism. Compositionally, the siliciclastics of both the zones (ILH and OLH) are arenite and wacke types with minimal variation in their detrital proportions, derived from the early Proterozoic (between 2.4-1.6Ga) Aravalli-Delhi Supergroup provenance. Nearly matching types and content of detrital modes and the lithofacies pattern of the ILH and OLH siliciclastics probably conclude the derivation from the rising (nearby) Aravalli-Delhi orogen and deposition in a foreland like situation.  相似文献   

Drought indicators-based integrated assessment of drought vulnerability: a case study of Bundelkhand droughts in central India   总被引：3，自引：1，他引：2  

T. Thomas  R. K. Jaiswal  Ravi Galkate  P. C. Nayak  N. C. Ghosh 《Natural Hazards》2016,81(3):1627-1652

  相似文献   

Automatic Delineation of Structural Boundaries using Curvature Analysis of Bouguer Gravity Data in Parts of Northwest Himalaya     

G. K. Ghosh 《Journal of the Geological Society of India》2018,91(5):589-595

Curvature describes about the bending of surface by which a surface deviates from flat plane or a curve deviates from straight. The Himalaya has numerous geodynamic features with complex geological setup and extreme undulating topography. In this context, interpretation of gravity data has been used for enhancing important features to delineate structural trend for understanding thrust-fault locations and crustal structural setup in north-west Himalaya. Gravity data interpretation not only help to study varying lateral changes in density with lithological changes but also properties of gradients to interpret sub-surface structure and edges of the geological features. Attempt has been made to interpret various curvatures analysis like maximum, minimum, most-positive and most-negative curvatures using Bouguer gravity data to estimate the automatic thrust-fault locations in Dehradun-Badrinath area falling in the north-western part of Himalaya, India.  相似文献   

Application of analytical hierarchy process (AHP) for flood risk assessment: a case study in Malda district of West Bengal,India     

Abhishek Ghosh  Shyamal Kumar Kar 《Natural Hazards》2018,90(1):349-364

A field experiment was conducted from 2 May 2010 to 1 May 2012 in the Gurbantunggut Desert, the second largest desert in China, to investigate saltation activity and its threshold velocity, and their relations with atmospheric and soil conditions. The results showed that saltation activity occurred more frequently during 08:00–20:00 Local Standard Time in spring and summer, with air temperatures between 20.0 and 29.0 °C, water vapor pressures between 0.6 and 0.9 kPa, soil temperatures between 25.0 and 30.0 °C, and a soil moisture lower than 0.04 m³/m³. At 2 m height, the saltation threshold velocity varied between 11.1 and 13.9 m/s, with a mean of 12.5 m/s. Threshold velocity showed clear seasonal variations in the following sequence: spring (11.7 m/s) < autumn (12.7 m/s) < summer (13.6 m/s). Affected by soil conditions, aeolian sand transport was weak, with an average annual aeolian sand that transported across a section (1.0 m × 2.0 m) of less than 6.0 kg.  相似文献   

Spatio‐temporal prediction of land surface temperature using semantic kriging     

Shrutilipi Bhattacharjee  Jia Chen  Soumya K. Ghosh 《Transactions in GIS》2020,24(1):189-212

Spatio‐temporal prediction and forecasting of land surface temperature (LST) are relevant. However, several factors limit their usage, such as missing pixels, line drops, and cloud cover in satellite images. Being measured close to the Earth's surface, LST is mainly influenced by the land use/land cover (LULC) distribution of the terrain. This article presents a spatio‐temporal interpolation method which semantically models LULC information for the analysis of LST. The proposed spatio‐temporal semantic kriging (ST‐SemK) approach is presented in two variants: non‐separable ST‐SemK (ST‐SemK_NSep) and separable ST‐SemK (ST‐SemK_Sep). Empirical studies have been carried out with derived Landsat 7 ETM+ satellite images of LST for two spatial regions: Kolkata, India and Dallas, Texas, U.S. It has been observed that semantically enhanced spatio‐temporal modeling by ST‐SemK yields more accurate prediction results than spatio‐temporal ordinary kriging and other existing methods.  相似文献   

Classification of glacial lakes using integrated approach of DFPS technique and gradient analysis using Sentinel 2A data     

Prateek Verma  Sanjay Kumar Ghosh 《国际地球制图》2019,34(10):1075-1088

It is important to identify and locate glacial lakes for assessing any potential hazard. This study presents a combination of semi-automatic method Double-Window Flexible Pace Search (DFPS) and edge detection technique to identify glacial lakes using Sentinel 2A satellite data. Initially, Normalized Difference Water Index (NDWI) has been used to identify water and non-water areas, while DFPS and Edge detection technique has been used to identify an optimum threshold value to distinguish between water and shadow areas. The optimal threshold from DFPS process is 0.21, while threshold value of gradient magnitude using edge detection process is 0.318. The number of glacial lakes identified using the above algorithm is in close agreement with previously published results on glacial lakes in Gangotri glacier using different techniques. Thus, a combination of DFPS and edge detection process has successfully segregated glacial lakes from other features present in Gangotri glacier.  相似文献   

Effective medium modeling to assess gas hydrate and free-gas evident from the velocity structure in the Makran accretionary prism, offshore Pakistan     

Ranjana Ghosh  Kalachand Sain 《Marine Geophysical Researches》2008,29(4):267-274

Seismic properties of sediments are strongly influenced by pore fluids. Stiffness of unconsolidated marine sediment increases with the presence of gas hydrate and decreases with the presence of gas. A strong bottom-simulating reflector (BSR) observed on a seismic profile in the Makran accretionary prism, offshore Pakistan, indicates the presence of gas hydrate and free-gas across the BSR. Elastic properties of gas depend largely on pressure and temperature. We, therefore, first determine the elastic modulus of gas at pressure and temperature calculated at the BSR depth in the study region. The interval velocities derived from the seismic data are interpreted by the effective medium theory, which is a combination of self-consistent approximation and differential effective medium theories, together with a smoothing approximation, for assessment of gas hydrate and free-gas. The results show the saturations of gas hydrate and free-gas as 22 and 2.4% of pore space, respectively, across the BSR.  相似文献   

New insights on petrography and geochemistry of impactites from the Lonar crater,India          下载免费PDF全文

Dwijesh Ray  Dewashish Upadhyay  Saumitra Misra  Horton E. Newsom  Sambhunath Ghosh 《Meteoritics & planetary science》2017,52(8):1577-1599

The Lonar impact crater, India, is one of the few known terrestrial impact craters excavated in continental basaltic target rocks (Deccan Traps, ~65 Ma). The impactites reported from the crater to date mainly include centimeter‐ to decimeter‐sized impact‐melt bombs, and aerodynamically shaped millimeter‐ and submillimeter‐sized impact spherules. They occur in situ within the ejecta around the crater rim and show schlieren structure. In contrast, non–in situ glassy objects, loosely strewn around the crater lake and in the ejecta around the crater rim do not show any schlieren structure. These non–in situ fragments appear to be similar to ancient bricks from the Daityasudan temple in the Lonar village. Synthesis of existing and new major and trace element data on the Lonar impact spherules show that (1) the target Lonar basalts incorporated into the spherules had undergone minimal preimpact alteration. Also, the paleosol layer as preserved between the top‐most target basalt flow and the ejecta blanket, even after the impact, was not a source component for the Lonar impactites, (2) the Archean basement below the Deccan traps were unlikely to have contributed material to the impactite parental melts, and (3) the impactor asteroid components (Cr, Co, Ni) were concentrated only within the submillimeter‐sized spherules. Two component mixing calculations using major oxides and Cr, Co, and Ni suggest that the Lonar impactor was a EH‐type chondrite with the submillimeter‐sized spherules containing ~6 wt% impactor components.  相似文献