Chemical Procedures for Rhenium Extraction from Geological Samples: Optimising the Anion Resin Bead Clean‐up Step     

Gang Yang  Aaron Zimmerman  Nicole C. Hurtig  Svetoslav V. Georgiev  Vineet Goswami  Judith L. Hannah  Holly J. Stein 《Geostandards and Geoanalytical Research》2020,44(2):231-242

Rhenium–osmium geochronometry for samples with low Re and complex matrices requires improved Re extraction methods. Here, we investigate plausible controls on efficiency and efficacy of Re extraction during our anion resin bead purification. Four different protocols are compared, each isolating a single variable to test. Rhenium concentrations for solutions at each step of each protocol document differences in chemical recovery/yield. The negative‐thermal ionisation mass spectrometry (N‐TIMS) signal intensity serves as a proxy for Re yield and purity. These data document correlations between the N‐TIMS signal intensity and (a) the duration of anion resin bead conditioning prior to loading with Re‐bearing solution, and (b) both duration and strength of nitric acid used during rinsing of the Re‐loaded anion resin bead. The optimal protocol improved Re signal intensity around fourteen times compared with our current Re extraction protocol, an aggregate of 2.4 times improvement in chemical recovery (yield) and 5.8 times improvement in emission efficiency (purity). Repeated N‐TIMS isotopic measurements on our in‐house Re standard solution (1407) verify that our optimal protocol‐3 does not fractionate Re isotopes. The improved anion resin bead method considerably lowers the Re detection limit and allows Re‐Os isotopic analysis of picogram‐level Re hosted in geological samples with complex matrices.  相似文献   

Correction to: Application of 1D and 2D hydrodynamic modeling to study glacial lake outburst flood (GLOF) and its impact on a hydropower station in Central Himalaya     

Sattar  Ashim  Goswami  Ajanta  Kulkarni  Anil V. 《Natural Hazards》2019,98(2):817-817

Natural Hazards - The article was published with the citation “Worni et al. (2012)”. The author group of the article would like readers to know that this information should instead...  相似文献   

Erratum to: Changes in western disturbances over the Western Himalayas in a warming environment     

R. K. Madhura  R. Krishnan  J. V. Revadekar  M. Mujumdar  B. N. Goswami 《Climate Dynamics》2015,44(3-4):1169-1169

  相似文献   

Simulation of heavy rainfall events over Indian region: a benchmark skill with a GCM     

Prashant Goswami  B. Kantha Rao 《Climate Dynamics》2015,45(7-8):1899-1911

  相似文献   

Pressure and temperature conditions for crystallization of metamorphic allanite and monazite in metapelites: a case study from the Miyar Valley (high Himalayan Crystalline of Zanskar,NW India)          下载免费PDF全文

S. Goswami‐Banerjee  M. Robyr 《Journal of Metamorphic Geology》2015,33(5):535-556

The textural and chemical evolution of allanite and monazite along a well‐constrained prograde metamorphic suite in the High Himalayan Crystalline of Zanskar was investigated to determine the P–T conditions for the crystallization of these two REE accessory phases. The results of this study reveals that: (i) allanite is the stable REE accessory phase in the biotite and garnet zone and (ii) allanite disappears at the staurolite‐in isograd, simultaneously with the occurrence of the first metamorphic monazite. Both monazite and allanite occur as inclusions in staurolite, indicating that the breakdown of allanite and the formation of monazite proceeded during staurolite crystallization. Staurolite growth modelling indicates that staurolite crystallized between 580 and 610 °C, thus setting the lower temperature limit for the monazite‐forming reaction at ~600 °C. Preservation of allanite and monazite inclusions in garnet (core and rim) constrains the garnet molar composition when the first monazite was overgrown and subsequently encompassed by the garnet crystallization front. Garnet growth modelling and the intersection of isopleths reveal that the monazite closest to the garnet core was overgrown by the garnet advancing crystallization front at 590 °C, which establishes an upper temperature limit for monazite crystallization. Significantly, the substitution of allanite by monazite occurs in close spatial proximity, i.e. at similar P–T conditions, in all rock types investigated, from Al‐rich metapelites to more psammitic metasedimentary rocks. This indicates that major silicate phases, such as staurolite and garnet, do not play a significant role in the monazite‐forming reaction. Our data show that the occurrence of the first metamorphic monazite in these rocks was mainly determined by the P–T conditions, not by bulk chemical composition. In Barrovian terranes, dating prograde monazite in metapelites thus means constraining the time when these rocks reached the 600 °C isotherm.  相似文献   

Geotechnical properties of the bank sediments along the Dhansiri River channel, Assam     

P. Kotoky  M. K. Dutta  R. Goswami  G. C. Borah 《Journal of the Geological Society of India》2011,78(2):175-183

The bank sediments along the extremely meandered Dhansiri River channel, a south bank tributary of the mighty Brahmaputra River, with erosion potentiality have been investigated to evaluate its certain geotechnical characteristics. The study has shown that the bank sediments are basically composed of CL and ML types of soil. These types of sediments are very much prone to liquefaction which in turn related to erosion susceptibility. The bank stability analysis has differentiated the studied stretch into unstable, at risk and stable zones. Most of the erosion affected zones along the channel reach under study are located within the unstable or at risk zones. The field study around Butalikhowa, Barguriagaon, Golaghat and Duchmuagaon areas along the channel with active erosion activity has supported our contention and practical utility of the present study. It is expected that such type of study will help in providing certain inevitable baseline information for various channel management practices for this extremely flood prone areas of Northeast India.  相似文献   

Analysis and quantification of contrasts in observed meteorological fields for foggy and non-foggy days   总被引：1，自引：0，他引：1  

Prashant Goswami  Sumana Sarkar 《Meteorology and Atmospheric Physics》2015,127(5):605-623

  相似文献   

Use of SARAL/AltiKa Observations for Modeling River Flow     

Praveen Gupta  Amit Kumar Dubey  Nandita Goswami  Raghvendra Pratap Singh  Prakash Chauhan 《Marine Geodesy》2015,38(3):614-625

In the absence of many gauging stations in the major and mighty river systems, there is a need for satellite-based observations to estimate temporal variations in the river water storage and associated water management. In this study, SARAL/AltiKa application for setting up hydraulic model (HEC-RAS) and river flow simulations over Tapi River India has been discussed. Waveform data of 40 Hz from Ka band altimeter has been used for water levels retrieval in the Tapi river. SARAL/AltiKa retrieved water levels were converted to discharge in the upstream location (track-926) using the rating curve available for the nearby gauging site and using linear spatial interpolation technique. Steady state simulations were done for various flow conditions in the upstream. Validation of river flow model was done in the downstream location (track-367) by comparing simulated and altimeter retrieved water levels (RMSE 0.67 m). Validated model was used to develop rating curve between water levels and simulated discharge for the downstream location which enables to monitor discharge variations from satellite platform in the absence of in situ observations. It has been demonstrated that SARAL/AltiKa data has potential for river flow monitoring and modeling which will feed for flood disaster forecasting, management and planning.  相似文献   

Impact of background error statistics on 3D-Var assimilation: case study over the Indian region     

V. Rakesh  P. Goswami 《Meteorology and Atmospheric Physics》2011,112(1-2):63-79

  相似文献   

Pacific coral oxygen isotope and the tropospheric temperature gradient over the Asian monsoon region: a tool to reconstruct past Indian summer monsoon rainfall     

Supriyo Chakraborty  Bhupendra N. Goswami  Koushik Dutta 《第四纪科学杂志》2012,27(3):269-278

Having recognized that it is the tropospheric temperature (TT) gradient rather than the land–ocean surface temperature gradient that drives the Indian monsoon, a new mechanism of El Niño/Southern Oscillation (ENSO) monsoon teleconnection has been unveiled in which the ENSO influences the Indian monsoon by modifying the TT gradient over the region. Here we show that equatorial Pacific coralline oxygen isotopes reflect TT gradient variability over the Indian monsoon region and are strongly correlated to monsoon precipitation as well as to the length of the rainy season. Using these relationships we have been able to reconstruct past Indian monsoon rainfall variability of the first half of the 20th century in agreement with the instrumental record. Additionally, an older coral oxygen isotope record has been used to reconstruct seasonally resolved summer monsoon rainfall variability of the latter half of the 17th century, indicating that the average annual rainfall during this period was similar to that during the 20th century. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献