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C. F. Binoy , George Mathew

Abstract

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George Mathew , Mathew P. Koshy , K. Mohanadas

Abstract

In a study on the insect pollinators of teak in Kerala, 17 species of. insects belonging to the orders Hymenoptera. Diptera and Lepidoptera were collected and identified. Maximum number of insects collected belonged to the order Hymenoptera. Among these, the solitary bees, Halictus sp., Prosopis pratensis and Allodope marginata were the most frequent visitors. None of the domesticated bee species was observed and this could probably be due to their absence in the vicinity. The possibility of enhancing pollination with the help of domesticated bee species needs to be explored.

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George Mathew ¹, R. V. Karanth ¹, T. K. Gundu Rao ², R. S. Deshpande ³

Affiliations
1 Department of Geology, M. S. University of Baroda, Vadodara - 390 002, IN
2 Regional Sophisticated Instrumentation Centre, Indian Institute of Technology, Powai, Mumbai - 400 076, IN
3 Isotope Division, Bhaba Atomic Research Centre, Trombay, Mumbai - 400 085, IN

Abstract

Beryl samples from Badmal mines, Orissa were studied by electron spin resonance, optical absorption and Mossbauer spectroscopy. It was found that on artificial irradiation, colourless beryls from Orissa turned to shades of yellow-green. On subsequent heating at 300°C, the hue changed to yellow and upon further heating at controlled conditions they turned to a more desirable sky blue, accounting for value addition. Continued heating above 500°C, however, rendered them colourless. Similar studies were also canied out on natural yellow, blue and green beryls from Orissa, all of which acquired a greenish hue on irradiation and turned colourless on heating to >500°C. Electron probe microanaiysis of beryls showed iron as the major transition element impurity, ranging in concentration between 0.5 to 0.7wt%. Investigations using electron spin resonance, optical absorption spectroscopy and Mossbauer spectroscopy reveal that colours produced were on account of Maxixe-type defect centres as well as radiation-induced oxidation of Fe²⁺ to Fe³⁺ ion and associated charge transfer process. It is interesting to note that the yellow and blue colour produced on irradiation as well as post irradiation heating showed similar hue to that of the natural ones, both having formed on account of similar charge transfer process. Thus, it can be inferred that natural yellow, blue and green colours in beryls comprising low iron impurities are due to prolonged irradiation in nature.

Keywords

Beryl, Colour, Irradiation, Heating, Electron Spin Resonance, Optical Absorption Spectroscopy, Mossbauer Spectroscopy, Orissa.

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R. V. Karanth ¹, Parag S. Sohoni ¹, George Mathew ¹, Anirudhha S. Khadkikar ¹

Affiliations
1 Department of Geology, M. S. University of Baroda, Vadodara - 390 002, IN

Abstract

The entire Gujarat State in general and Kachchh region in particular experienced one of the most devastating earthquakes in the Indian shield on 26^th January 2001. This earthquake has caused significant damage to life and property and is one of the most important seismic events that can serve as a modern analogue for studying ground deformation caused on account of large magnitude earthquake in the stratigraphic record. Mainly four different kinds of ground deformation have been observed in Kachchh: (a) large scale ground fissuring, (b) lateral spreads/Faulting, (c) rock falls and slumping and (d) liquefaction and fluidization. Intense ground deformation is seen in the domain of Kachchh Mainland Fault (KMF). Most of the intense liquefaction and ground-Rupture sites fall along the extent of KMF which indicates that a part of Kachchh Mainland Fault has been activated between Kunaria in the west to Adhoi in the east during this earthquake.

Keywords

Earthquakes, Seismicity, Kachchh Mainland Fault, Bhuj, Gujarat.

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