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Muthuvairavasamy Ramkumar Matthias Alberti Franz T. Fürsich Dhirendra Kumar Pandey 《Chemie der Erde / Geochemistry》2012,72(2):141-148
The Upper Callovian-Oxfordian strata of the Kachchh Basin, western India, record three positive excursions of phosphorus. They have been documented in three sections of the Chari Formation from different parts of the basin. Corroboration of field and petrographic data with trends of major and trace elemental data and elemental ratios of the strata revealed that these excursions were coeval with reduced chemical weathering in the source area and significant reduction of siliciclastic influx to the depositional sites. The study also revealed the intrabasinal source of P, and minor sea-level fluctuations and resultant episodic sediment recycling as the causative factors. Considering the geographic locations of the three sections, the phosphorus anomalies seem to be controlled by a regional and/or basin-scale process, if not linked with global signals. Temporal resolution of these anomalies suggests that the processes were episodic and related to short term climate/relative sea-level cycles, the durations of which could be unraveled with high-resolution biostratigraphic data. 相似文献
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Matthias Alberti Franz T. Fürsich Dhirendra K. Pandey 《International Journal of Earth Sciences》2013,102(5):1321-1336
A high-resolution stable isotope (δ18O, δ13C) analysis of a specimen of the oyster Actinostreon marshi (J. Sowerby, 1814) from the Lower Oxfordian of the Kachchh Basin in western India was used to reconstruct average seasonal temperatures over a consecutive time interval of 10 years. The recorded temperatures during this period varied around a mean of 13 °C (maximum: 15.1 °C; minimum: 11.4 °C) with a generally low seasonality between 1 and 3 °C. Such weak seasonal changes can be expected from a subtropical palaeolatitude between 25° and 30°S. However, the low average temperatures are in contrast to studies on broadly contemporaneous fossils from Europe and the southern Malagasy Gulf which point to much warmer conditions in these areas. It is therefore proposed that the low temperatures in the Kachchh Basin are caused by upwelling currents which influenced the north-western coast of India during the Late Jurassic. 相似文献
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Data from the SESAME storm-scale network are used in computing the momentum budget of the prestorm, storm, and poststorm environment of a severe storm complex. In the prestorm period geostrophic flow dominates the environment. With progression into the storm period all terms in the momentum equation become important, as a significant ageostrophic component in the momentum field develops. Turbulent effects are estimated as a residual, and the results indicate that they are comparable in magnitude to the other terms. Their effect is to decrease the positive momentum, particularly at levels above 500 mbar, where the vertical motion is the strongest. Vertical profiles of area means ofu andv indicate that the storm is apparently redistributing momentum downwards, thus reducing the mean shear. In the poststorm period the flow once again becomes largely geostrophic, and a maximum in wind speed reappears at upper levels. 相似文献
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Ravindra W. Gaikwad S. A. Misal Dhirendra D. V. Gupta 《Arabian Journal of Geosciences》2011,4(1-2):85-89
The mining industry faces stringent effluent discharge regulations and has acknowledged that it is necessary to look into innovative technologies to recycle considerable amount of effluent rather than discharging into surface water. Effluents from mines give rise to aesthetic unpleasantness. The focus of the investigations was to cope with more stringent effluent discharge regulations and to protect the ecosystem from harmful pollutants in the mine effluents. Copper is one of the heavy metal in the mine systems, which are known to be a harmful element. The present study has been undertaken to investigate a process that might remove Cu(II) from mine waste water by using natural zeolite, such as stilbite, and compared with synthetic resins like CSA-9 and CSA-609D. In this study, natural zeolite was used as a low-cost adsorbent to evaluate its ability to remove heavy metals from acid mine drainage. The zeolite used in this study is the natural clay mineral from the Nizarneshwar Hills of Western India. Three resins tested are CSA-9, natural zeolite–stilbite, and CSA-609D. Batch testing has been conducted to select effective ion-exchange resins for copper removal and to determine effective regenerants for regeneration of exhausted resins. All tests were conducted at bench scale and in batch mode. Three strong acid cation exchangers were evaluated to compare their metal removal capacities. The metal concentration in the effluent was reduced with all resins tested. It was found that, among all the three types of natural zeolite, stilbite shows the highest removal efficiency of copper in every parameter that is considered for evaluating the performance of resins. 相似文献
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The Kachchh Basin and the Jaisalmer Basin are two neighboring Mesozoic sedimentary basins at the western margin of the Indian
craton. The Jurassic succession of the Kachchh Basin is more complete and more fossiliferous than that of the Jaisalmer Basin.
Consequently, intrabasinal correlation of the sedimentary units has been possible in the Kachchh Basin, but not in the Jaisalmer
Basin. However, some marker beds existing in the Kachchh Basin can be recognized also in the Jaisalmer Basin. Ammonite evidence
shows that they are time-equivalent. The following four units form marker intervals in both basins: (1) the pebbly rudstone
unit with Isastrea bernardiana and Leptosphinctes of the Kaladongar Formation (Kachchh Basin) and the Isastrea bernardiana-bearing rudstone of the Jaisalmer Formation (Jaisalmer Basin) both represent transgressive systems tract deposits dated as
Late Bajocian; (2) bioturbated micrites with anomalodesmatan bivalves within the Goradongar Yellow Flagstone Member (Kachchh
Basin) and bioturbated units in the Fort Member (Jaisalmer Basin) represent maximum flooding zone deposits of the Middle to
Late Bathonian; (3) trough-crossbedded, sandy pack- to grainstones of the Raimalro Limestone Member (Kachchh Basin) and the
basal limestone-sandstone unit of the Kuldhar section of the Jaisalmer Formation (Jaisalmer Basin) correspond to Late Bathonain
transgressive systems tract deposits; and (4) ferruginous ooid-bearing carbonates with hardgrounds of the Dhosa Oolite member
(Kachchh Basin) and the middle part of the Jajiya Member (Jaisalmer Basin) are Oxfordian transgressive systems tract deposits.
The fact that in both basins similar biofacies prevailed during certain time intervals demonstrates a common control of their
depositional history. As the two basins represent different tectonic settings, the most likely controlling factors were the
relative sea-level changes produced by eustatic processes, a common subsidence history of the northwestern margin of the Indian
craton, and the paleoclimate. 相似文献
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Maharana P. Kumar Dhirendra Kumar Rajesh Singh Rupendra Dimri A. P. 《Theoretical and Applied Climatology》2022,148(3-4):1459-1476
Theoretical and Applied Climatology - This study diagnoses the Satna flood event in the Tons River basin. The occurrence of this intense flood is attributed to the rainfall associated with the... 相似文献
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Matthias Alberti Franz T. Fürsich Dhirendra K. Pandey Debahuti Mukherjee 《Journal of the Geological Society of India》2017,89(3):259-270
The Jurassic succession of Gangta Bet in the Kachchh basin of western India comprises around 130 m of mostly siliciclastic rocks. The strata belong to the Gangta Member of the Gadhada Formation and are herein sub-divided into four units: the Gangta sandstone beds, the lower silty sandstone beds, the upper silty sandstone beds, and the Gangta ammonite beds. These units can be separated by three marker horizons: the Brachiopod bed, the Gangta Conglomerate Bed, and the Gervillella Bed. Ammonites indicate an Oxfordian age for the upper half of the succession, but the scarcity of identifiable fossils in its basal part so far prevented precise biostratigraphic assignments. The shallow-water sediments can be interpreted as parasequences as a result of minor sea-level changes. Deposition took place close to the palaeo-coastline at water depths around the fair-weather wave-base. 相似文献
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