Studies on South Indian radioactive minerals. Part I. Samarskite from Nellore

Samarskite, a radioactive niobotantalate occurring in the Nellore pegmatites, has been studied in detail. The investigations comprise the determination of physical and optical characters, chemical composition, autoradiographic studies, distribution pattern, calculation and interpretation of age. The available data on Nellore Samarskite has been critically examined and it has been shown that the controversy raised by Holmes concerning the age of the Eastern Ghats can be solved, if the samarskite specimen analysed by Sarkar and Sen Sarma is understood to belong to the Gaya group of minerals, as has been later suggested. A tentative Archaean succession table has also been suggested

Studies on diffusion. Part I. Diffusion of radioactive matter through plates

As a part of an attempt to develop new methods of measurement of diffusion constant of metals and non-metals into minerals using radioactivity techniques, expressions are derived to relate the processes of diffusion and the emission of alpha-particles under three sets of possible experimental conditions. The first case pertaisn to a plate whose thickness is equal to the characteristic range of the alpha-rays of the radio-nuclide used. Under the second case is considered a plate thicker than the characteristic range fo the alpha-rays in the plate. The third deals with cases wherein the radioactive matter used emits alpha-rays with different ranges less than the thickness of the plate

Sea breeze Initiated Rainfall over the east Coast of India during the Indian Southwest Monsoon

Sea breeze initiated convection and precipitation is investigated along the east coast of India during the Indian southwest monsoon season. The sea breeze circulations are observed approximately 70 to 80% of the days during the summer months (June to August) along the Chennai coast. Observations of average sea breeze wind speeds are stronger at a rural location as compared to the wind speeds observed inside the urban region of Chennai. The sea breeze circulation is shown to be the dominant mechanism for initiating rainfall during the Indian southwest monsoon season. Roughly 80% of the total rainfall observed during the southwest monsoon over Chennai is directly related to the convection initiated by sea breeze circulation

Studies on South Indian radioactive minerals II. Allanite from Madura

Allanite, a cerium-bearing epidote occurring in the pegmatites of Kavarkattumalai, Madura District, has been studied in detail. The investigations comprise the determination of physical and optical characters, chemical composition, mineral formula, and autoradiographic studies. Attempts have been made from a study of the data on metamict and non-metamict allanites to formulate the changes that allanite undergoes when it becomes metamict. Evidence has been collected to show that the allanite from Madura had become metamict and is hence of dubious value as an age index

Center in India offers training in water management

The Mahadevan International Centre for Water Resources Management in Hyderabad, India, conducted an interactive training course 7-17 December 2002 on the relationship of land surface hydrological processes to water resources management and extreme weather events. The course was designed to address the training needs of government personnel in Andhra Pradesh State working in the area of water resources management, particularly in the context of severe drought and over-exploitation of groundwater in the State. The Mahadevan Centre, modeled after the Abdus Salam International Centre for Theoretical Physics in Trieste, Italy, serves as a clearinghouse for information pertaining to water sciences and technologies for the developing countries

Th/U and U/K ratios as possible aids in prospecting for uranium deposits in peninsular India

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Isotopic ages from the Eastern Ghats and Cuddapahs of India

Rubidium-strontium and potassium-argon dating of whole rocks and separated biotites from charnockites and granites of the Eastern Ghats delineate two episodes after the culmination of the Eastern Ghats orogeny 1600 m.y. ago: (1) emplacement of charnockites and granites 1300 to 1520 m.y. ago and (2) their subsequent metamorphism and uplift 500 m.y. ago (postdating the deposition of the Cuddapahs). The 500-m.y. cycle is represented in the southwest coast of India (Travancore) and Ceylon, and the age data are consistent with structural and other geological evidence. Whole-rock K-Ar ages of five dolerites emplaced in the Lower Cuddapahs in the western part of the Cuddapah Basin, and of two slates of the Cumbum stage of the Nallamalai series, permit the dating of the following events in the history of the Cuddapah Basin: (1) the initiation of the Cuddapah sedimentation sometime after the completion of the Eastern Ghats orogeny (1600 m.y. ago), but before 1160 m.y. ago (minimum age limit for dolerites), and (2) metamorphism of the Cuddapahs about 500 m.y. ago (as indicated by the slate ages)

Age of the Cuddapahs, India

In India, the term 'Archaean' has been applied to the formations below the so-called Eparchaean unconformity-the unconformity at the base of the Cuddapahs and their equivalents. The importance of the Cuddapahs as a chronostratigraphic unit arises out of this consideration. Investigations were initiated by me to date the galenas occurring in Cuddapahs and related formations. This communication presents preliminary results of the lead isotope studies

Age of the samarskite of Kishengarh, Rajasthan India

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