007480   Raut N S;Gholba M;Pejaver M (Dep of Zool, B.N.Bandodkar Coll of Sci, Chendani, Thane-400 601) : Pls response (Zooplankton) to physico-chemical parameters from Thane lakes (Maharashtra). J Aquatic Biol 2006, 21(1), 32-6.

In four study lakes namely Ambeghosale, Rewale, Makhamali and Upavan; the zooplankton samples were collected through out the year. During the course of statistical analysis zooplankton analysis was done for the four study lakes in the Thane city. PLS response (zooplankton) to physico-chemical parameter were represented first time for Thane lakes. The study shows tat calculated PLS response of zooplankton is very near to actual response of zooplankton in all the four lakes studied.

illus, tables, ref

007479   Rameshwar Rao D (NO, Wadia Inst of Himalayan Geol, 33, GMS Road, Dehra Dun-248 001, Email: raodr@wihg.res.in ) : Evolutionary history of the Schirmacher region, East Antarctica. Himalayan Geol 2006, 27(1), 81-94.

Retrograde P-T history is envisaged for Proterozoic complex of Schirmacher region of East Antarctica, involving three phases of metamorphism in the region, an early granulite facies metamorphism (7.3±0.3 kbar, 827±29°C), a late granulite phase of metamorphism (6.2±0.4 kbar and 752±22°C), and a third phase of subsequent retrograde amphibolite facies metamorphism (5.4±0.4 kbar, 654±27°C). The geochemistry of the mafic granulites indicates that they are high Mg-tholeiites. Their Nd^i> and Srⁱ isotopic compositions, high field strength elements, and the heavy rare-earth elemental compositions are consistent with a mantle source. The rocks, however, also show enrichment of large ion-lithophile elements and Nb trough, suggesting the characteristics of subduction zone magmatism. The isotopic studies indicate that the region was active<126>960 Ma and resulted in the metamorphism of<126>1200 Ma mafic magmatism, while reworking during subsequent tectonothermal overprinting around 886 Ma is also observed. The geochemical studies of felsic gneisses on the other hand, show signatures of I-type suggesting their production from the partial melting of early formed mafic-intermediate crustal material. From the geochemical and isotopic studies carried out on the Schirmacher region of East Antarctica, it is envisaged that accretion of the juvenile crust took place around 1200 Ma, with a tectonothermal overprinting taking place around 850 Ma.

8 illus, 4 tables, 68 ref

007478   Rajalakshmi S;Sreelatha K (Dep of Zool, KM Cent for Post Grad Stud, Pondicherry-8) : Diversity of ichthyofauna in Gautami Godavari estuary Yaman, Union Teritory of Pondicherry, India. J Aquatic Biol 2006, 21(1), 45-8.

Reveals the biodiversity of ichthyofauna, taxonomical position of species and fishery statistics of Gautami-Godavari estuary during the year March 2004 - Feb 2005 has been investigated. During the study, 44 fish species belonging to 16 families and 26 genera were observed and conservation measures for the decline in the abundance were also discused.

2 tables, 19 ref

007477   Purohit K K;Mukherjee P K;Saini N K;Khanna P P;Rathi M S (NO, Wadia Inst of Himalayan Geol, Dehra Dun-248 001) : Geochemical survey of stream sediments from upper parts of Alaknanda, Mandakini, Bhilangana and Bhagirathi catchments Garhwal Himalaya. Himalayan Geol 2006, 27(1), 31-9.

A set of 19 major and trace elements determined on stream sediments from the upper parts of Alaknanda-Mandakini-Bhilangana-Bhagirathi catchments of the Garhwal Himalaya are used to study their spatial distribution in the area. The geochemical datasets are statistically analysed to understand the assocation of elements. A comparision of the elemental abundances with the average upper continental crust (AUCC) indicates the except for SiO₂, MgO, and TiO₂ all other major elements are depleted relative to AUCC, whereas most of the trace elements abundances are enriched. The enrichments of SiO₂ may be due to quartz dilution effect as evident by its inverse correlation between most of the major oxides and trace elements (Ni, Co). Positive correlation of Cu with Zn and Pb, is related to possible sulphide mineralisation, where as the enhanced concentration of Cr as compared to Ni and AUCC may be diagenetic or due to co precipiation of Cr with Fe oxides.

4 illus, 1 table, 39 ref

007476   Poroshin V D;Morozov A G;Senkevich A E (NO, , ) : Hydrochemical methods of development of subsalt and intersalt oil reservoirs (on an example of fields Belarus) Part V. Indian J Petrol Geol 2005, 14(2), 79-87.

4 ref

007475   Philip G;Sah M P;Virdi N S (NO, Wadia Inst of Himalayan Geol, 33-GMS Road, Dehra Dun-248 001, Email: fkutty@rediffmail.com) : Morpho-structural signatures of active tectonics in parts of Kangra Valley, NW Himalaya, India. Himalayan Geol 2006, 27(1), 15-30.

Morpho-structural analysis using remotely sensed data along with selected field investigation in delineating the phenomenon of active tectonics experienced in parts of the Kangra Valley, NW Himalaya which is the epicentral zone of 1905 Kangra earthquake. The recent tectonic activity in this valley is reflected in the form of dislocation of landforms and definite channel shift along major and minor lineaments. Creation of various tectonic landforms and the relative positions of the Quaternary depostis also corroborate active tectonics in this region. The stream gradient indices how a gradual increase of SL value around MBT, and an abrupt high SL value at 1400-1600m along the MBT indicates phases of rejuventation of the area.

12 illus, 3 tables, 35 ref

007474   Muley D V;Patil I M (Dept. of Zool, Shivaji Univ, Kolhapur-416 004) : Study of water quality and fish diversity of Pauna river, Maharashtra. J Aquatic Biol 2006, 21(1), 68-75.

Water quality together with the ichthyofauna of Fauna river, in Pune District, Maharashtra has been investigated. The investigation was undertaken for a period of one year, by establishing four sampling stations along 53 km total stretch of the river. The river Fauna is highly contaminated downstream with untreated sewage & industrial effluents, while flowing through Pimpri - Chinchwad city. The high value of C0₂, BOD, COD, chloride, phosphate, nitrate, hardness & low value of DO at discharge zone indicates increase in organic pollution as we go down the river stretch. Altogether 32 fish species belonging to 22 genera distributed in 4 orders were identified. Of these species 23 species were not found in downstream. The discharge zone is dominated by pollution tolerant fish species O. mossambicus.

1 illus, 1 table, 25 ref

007473   Kundal P;Bhagat M B;Humane S K (Postgrad Dep of Geol, R.T.M.Nagpur Univ Law Coll Square, Nagpur-440 001) : Coralline algae from Alibag formation (late oligocene to basal miocene), Bombay offshore basin, India and their paleoenvironmental significance. Indian J Petrol Geol 2005, 14(2), 39-48.

Paper documents four nongeniculate coralline algae viz. Lithoporella sp., Spongites sp., Mesophyllum sp. and Lithophyllum sp. and two geniculate coralline algae viz. Corallina sp. and Arthrocardia sp. from the core samples of limestone belonging to the Alibag Formation (Late Oligocene to Basal Miocene) ofBombay Offshore basin, India. The coralline algal assemblage suggests that the Alibagh formation was deposited under moderately high energy conditions at a depth of 20 m in tropical warm waters.

12 illus, 1 ref

007472   Kulkarni B G;Deshmukh V V;Jaiswar A K (Dep of Zool, The Inst of Sci, Mumbai-400 032) : Diversity, population density and biomass of some molluscs at Haji Ali sea shore of Mumbai (Bombay), Maharashtra, West Coast of India. J Aquatic Biol 2006, 21(1), 56-9.

Inspite of deteriorating environmental conditions, seven species of gastropod belonging to seven genera and two species of bivalve representing two genera were recorded during the study at Haji ali sea shore of South Mumbai. Density of Euchleus asper, Trochus radiatus, Nerita oryzarum and Bursa tuberculata was highest in post-monsoon and pre-monsoon. Similarly a seasonal variation in biomass of these gastropods was also noted. Indices like Shannon's diversity, Pielou's evenness index and dominance index did not show significant variations throughout the period of investigation.

3 tables, 12 ref

007471   Krishnamoorthy G;Rajalakshmi S;Govindan R (Dep of Zool, Kanchi Mamunivar Cent for Post Grad Stud, Pondicherry-605 008) : Brachyuran crab diversity in Ariankuppam estuary, Pondicherry, union territory, India. J Aquatic Biol 2006, 21(1), 64-7.

Brachyuran crab diversity were studied in two stations of Ariankuppam estuary. A total of 13 79^°50' species of crab belonging to 5 families were recorded in mangrove rich area and 7 species of 4 families were recorded in mangrove free area during the post monsoon season (Dec. 2005 to Feb.2006). The density of the crabs also varied between the two habitats. The mangroves with vast network of roots and trunks offer a good niche for the brachyuran crabs.

1 illus, 2 tables, 14 ref

007470   Kamath D;Vijaya Kumara;Kiran;Tirumala B R; Puttaiah S (Dep of Envir Sci, Kuvempu Univ, Shankaraghatta-577 451) : Phytoplankton for biomonitoring of organic pollution in two tanks of Shimoga district, Karnataka. J Aquatic Biol 2006, 21(1), 7-9.

Two tanks situated in Shimoga district were selected for their phytoplankton diversity and the possibility of using it as bio monitors of organic pollution. Purle tank has very low diversity with blooms of Microcystis aeruginosa, Phormidium Sp., Arthrospira platenensis and Spirulina nordestedtii. These algae occurred as regular blooms in all the seasons. Hosalli tank supports a wide diversity of phytoplankton and less polluted. The use of algae for bio monitoring of organic pollution indicates that Purle tank, which regularly receives sewage is heavily polluted and Hosalli tank is mesotrophic in nature because of mild anthropogenic activities.

2 tables, 13 ref

007469   Dinakaran S;Anbalagan S (PG Dep of Zool Cent for Res in Aqu Ent, The Madura Coll, Madurai-625 011, Email: dinkarji@gmail.com) : Seasonal variation and substrate selection of aquatic insects in a small stream of Sirumalai hills of Southern Western Ghats. J Aquatic Biol 2006, 21(1), 37-42.

Seasonal variation and substrate selection of aquatic insects were studied in a small stream of Southern Western Ghats. Samples were collected in triplicate from different substrates {rocky bottom, gravel, loose stones and pool). A total of 2670 individuals of aquatic insects belonging to 17 genera, 13 families and 9 orders were collected. Species diversity index indicated generally higher values (2.68 and 2.7) between September and October (Northeast monsoon). Lower values (1.82) were recorded in the dry season (May). Ephemeroptera and Trichoptera were co-dominant on the rocky substratum, gravel/rubble and in loose stones. Hemiptera, followed by Diptera, Trichoptera and Odonata, dominated the insect fauna in pools.

1 illus, 4 tables, 26 ref

007468   Corvinus G (Nepal Res Cent, , P.O. Box 180, Kathmandu, Nepal, Email: gudruncorvinusompuserve.de) : The siwalik stratigraphy of Surai Khola, Nepal: A re-evaluation of the stratigraphy and the original road traverse. Himalayan Geol 2006, 27(1), 41-71.

Deals with the stratigraphy and fauna of the Surai Khola Siwaliks in Nepal and presents a compass road traverse of the ca. 5000 m strata of the Surai Khola succession with all recorded faunal, floral and palaeomagnetic data incorporated in its lithology. Rich mega plant fossils and pollen are recorded in the traverse for the Lower and Middle Siwaliks, and the Upper Siwaliks are represented by a fauna equivalent to the Hexaprotodon sivalensis and the Elephas planifrons Interval zones deriving from multistoried sandstones. In the Rato Khola area further east a rich vertebrate fauna of both the H. sivalensis and the E. planifrons zones was recorded from similar multistoried sandstones. The faunal and floral remains represent predominantly in situ recordings and the presented data establishes a detailed chronostratigraphy for the Siwalik fauna and flora in Nepal. The floral content points to a change from tropical humid to seasonal monsoonal vegetation during the Miocene-Pleistocene transition. The importance of the presented data lies in the fact that a technically uninterrupted sequence of the last 13 million years is recorded with all faunal and floral findings in its chronological framework and establishes the eastern-most evidence of an Upper Siwalik fauna in the Himalayan foothills.

22 illus, 1 table, 37 ref

007467   Celik H E;Aydin A;Ozturk T;Dagci M (IU Orman Fakultesi, , 34473 Bahcekoy Sariyer, Istanbul, Turkey, Email: hecelik@istanbul.edu.tr) : Causes of the 1998 Bartin river flood Western Black sea region of Turkey. J envir Biol 2006, 27(2), 341-8.

Vast flood in the Western Black Sea region of Turkey in May 1998 caused great loss of life and significant damage. Communication network, transportation, and construction cost of the disaster was estimated around US $500 million. Since flood area was relatively large, only Bartin river watershed were analysed and investigated within the scope of the study. It is very common having intense summer showers, which results in floods and landslides in the region. Land use changes in Turkey are rapid; therefore, actual land use format and its recent change were determined using remote sensing. Geographic Information System (GIS) was employed to evaluate the data collected in the area. Prolonged rainfall on saturated soil by antecedent rainfall; misuse of land both in upper and lower watersheds are main, reasons affecting the formation of such a flood in Bartin river watershed.

5 illus, 2 tables, 20 ref

007466   Borgohain S;Gogoi K D (NO, , ) : Emulsion flow in Bhogpara core sample with emphasis on enhanced oil recovery. Indian J Petrol Geol 2005, 14(2), 55-77.

Describes the flow of stable emulsions through porous media of well no 2 of the Bhogpara area belonging to Bhogpara oil field of Assam from a depth of 3837-3847m. The emulsion is oil in water type where the oleic phase is paraffin oil of viscosity 113.51cp and density 886 kg/m³ and the aqueous phase is 3000 ppm brine or 3000 ppm of brine along with 0.3% Black liquor in distilled water. It was observed that emulsion does not flow through the porous media as a viscous continuum, nor by squeezing through the pore constrictions, but by capture of the dispersed phase with subsequent permedability reduction to the continuous phase. The dispersed phase is the oleic phase and the continuous phase is the aqueous phase. An attempt is also made to release the captured oil blobs from the porous media first by brine flooding and later by surfactant flooding. The surfactant is Black Liquor, a waste from Nowgong Paper Mill of Jagiroad. It is added to the aqueous phase of the emulsion. A quantitative analysis of the amount of captured oil that is released by brine and surfactant flooding is also done. the results after flooding experiments show that of the total oil recovered, 71.07% is by brine flooding and 28.93% by surfactant flooding.

11 illus, 11 tables, 5 ref

007465   Bisht M P S;Mehta m;Nautiyal S K (Dep of Geol, H.N.B. Garhwal Univ, Srinagar, Garhwal-246 174) : Geomorphic hazards around Badrinath (Uttaranchal), and control measures. Himalayan Geol 2006, 27(1), 73-80.

Snow and debris avalanches are the most common phenomena in the high altitudinal zones (above 3000 m) of Uttaranchal Himalaya. This cause heavy damage to life and property in areas of settlements located in the upper reaches of Alaknanda and Dhauliganga valleys. Investigations were carried out to delineate the active avalanche prone zones as well as identify areas of rock fall, debris slide, soil creep etc. around the famous pilgrimage site of Badrinath. Detailed geological, geomorphological studies and hazard zonation mapping of the area were carried out and some control measures are suggested. The impact of surface processes in the geological past has continuously changed the landscape scenario of the region. The signatures of Pleistocene glaciations in the form of remnants of end-moraines, lateral-moraines, striations on bed rocks, deep epigenetic gorges, glacial troughs and hanging valleys are seen in the Alaknanda valley from Pandukeshwar to Alkapuri Bank. Evidence of recent diastrophic movements are preserved in the evolution of three well marked paired terraces and records of at least five phases of colluvial fan formation. Sedimentological records and topographic expression of the Alaknanda valley indicate that there were at least three major episodes of river blockades in the Badrinath area in the recent past. At certain points abrupt changes in the valley profile associated with active mass movements indicate phases of recent reactivation along N-S and NE-SW oriented tectonic. Some remedial measures for selective sites have been suggested to reduce the impact of avalanches in and around Badrinath area.

7 illus, 1 table, 9 ref

007464   Bhagde R V (NO, , 8, Chandrasen Apartment, 34/15 Erandawane, Lane No.8, Prabhat Road, Pune-411 004) : Study of condition indices of the green mussel Perna viridis from Mirya bay in Ratnagiri district of Maharashtra. J Aquatic Biol 2006, 21(1), 53-5.

Green mussels Perna viridis from Mirya bay in Ratnagiri district of Maharashtra were collected and lengthwise grouped as small, medium and large. Different methods were used to determine condition index of the mussels using Ci-volume, Ci-shell and Ci-body. The mussels of the small sized groups showed comparatively high values of Ci-than medium and large sized mussels, and in addition Ci-shell and Ci-body of these groups were little higher than Ci-volume has been seen.

2 tables, 10 ref

007463   Ahmad A H M;Ahmad Md N;Khan A F;Bhatt G M (Dep of Geol, Aligarh Muslim Univ, Aligarh-202 002) : Depositional environments and diagenesis of the upper part of the Jhurio formation, Jhurio dome, Kachchh, Gujarat. Indian J Petrol Geol 2005, 14(2), 23-37.

Describes 08 microfacies types in Jhurio hill of Jhurio Formation (Kachchh Mainland). Two types of cement present in the studied limestone include blocky and syntaxial overgrowths. Microfacies association represent depositional environment from subtidal to intertidal zones. The study also eveals that mechanical compaction has largely controlled porosity of these limestones, but micritization and neomorphism have also contributed significantly in this respect. Diagenetic signatures suggest that phreatic conditions in marine environments have been dominant, but deep burial diagenesis has also played its role in shaping these rocks.

12 illus, 26 ref

006336   Yadav R R;Jayendra Singh;Dubey B;Misra K G (NO, Birbal Sahni Inst of Palaeobotany 53 Univ Rd, Lucknow-226 007) : A 1584-year ring width chronology of juniper from Lahul, Himachal Pradesh: prospects of developing millennia-long climate records. Curr Sci 2006, 90(8), 1122-6.

Reports fifteen Hundred Eighty Four-year (AD 420-2003) long ring width chronology of Himalayan pencil cedar from cold arid region in Lahul, Himachal Pradesh. Ring width variations in trees at this site are found to be associated with variations in precipitation from previous growth years' September to concurrent May. Potential of this chronology in developing millennia-long hydrological records is recognized. Strong relationship between the present Himalayan pencil cedar chronology and two Himalayan cedar ring width chronologies prepared earlier from stands adjacent to the present site, demonstrates the utility of tree ring data network of these species in developing robust reconstructions needed for better insight into climate variability in longer perspective in the precipitation-deficient trans Himalayan region.

4 illus, 2 tables, 22 ref

006335   Venkatachalam G (Civ Engng Dep, Indian Inst of Technol Bombay, Powai, Mumbai-400 076, Email: gvee@civil.iitb.ac.in) : Reliability and risk analysis of slopes. Indian Geotech J 2006, 36(1), 1-66.

Proposes point-estimate based methods for analysis of reliability, including system reliability, spatial variation of reliability and regional hazard. The proposed methods are applied to natural and man-made urban slopes, such as geotextile reinforced earth slopes and the need for reliability analysis is illustrated. The usefulness of centrifuge modelling has been also highlighted.

31 illus, 30 table, 47 ref

006334   Thakur V C (NO, Wadia Inst of Himalayan Geol, Dehra Dun-248 001, Email: thakurvc@wihg.res.in) : Reassessment of earthquake hazard in the Himalaya and implications from the 2004 Sumatra-Andaman earthquake. Curr Sci 2006, 90(8), 1070-2.

2 illus, 22 ref

006333   Thakkar M G;Goyal B;Patidar A K;Maurya D M; Chamyal L S (Geol Dep, R R Lalan Coll, Bhuj, Kachchh-370 001, Email: lschamyal@yahoo.com) : Bedrock gorges in the central mainland Kachchh: implications for landscape evolution. J Earth Syst Sci 2006, 115(2), 249-56.

Kachchh possesses a fault-controlled first-order topography and several geomorphic features indicative of active tectonics. Though coseismic neotectonic activity is believed to be the major factor in the evolution of the landscape, detailed documentation and analysis of vital landscape featres like drainage characteristics, bedrock gorges and terraces are lacking. The study is a site-specific documentation of gorges developed in the central part of the mainland Kachchh. Analyzed and interpreted four gorges occurring on either side of Katrol Hill Fault (KHF). The Khari river gorge is endowed with six levels of bedrock terraces, some of which are studded with large potholes and flutings. Since no active development of potholes is observed along the rivers in the present day hyper-arid conditions, infered an obvious linkage of gorges to the humid phases, which provided high energy runoff for the formation of gorges and distinct bedrock terraces and associated erosional features. Development of gorges within the miliolites and incision in the fluvial deposits to the south of the KHF indicates that the gorges were formed during Early Holocene. However, ubiquitous occurrence of gorges along the streams to the south of KHF, the uniformly N40°E trend of the gorges, their close association with transverse faults and the short length of the exceptionally well developed Khari river gorge in the lo-relief rocky plain to the north of KHF suggests an important role of neotectonic movements.

5 illus, 1 table, 15 ref

006332   Thakkar M G;Goyal B (Dep of Geol, R.R. Lalan Coll, Bhuj, Kachchh-370 001, Email: mgthakkar@rediffmail.com) : Historic submergence and tsunami destruction of Nancowrie, Kamorta, Katchall and Trinket Islands of Nicobar district: Consequences of 26 december 2004 Sumatra-Andaman earthquake. Curr Sci 2006, 90(7), 989-4.

Twenty six December 2004 Sumatra-Andaman earthquake is one of the largest plate-boundary earthquakes in the recent seismic history of the world. This earthquake has also generated the greatest tsunami run-up and coastal devastation ever recorded. The field study at four major islands of Nancowrie group of Nicobar District in Andaman and Nicobar archipelago has revealed that the islands are vertically subsided by 1.0-1.75 m with the submergence of coastal land area by thousands of square kilometers. It is also suggested based on our field observations that societal and socio-economic rejuvenation of the islands will need resurvey of entire topography of the islands, coastal bathymetry mapping and identification of newly developed ecological regimes.

6 illus, 17 ref

006331   Somani R L (Dep of Geol, Univ of Raj, Jaipur-302 004, Email: rlsomani@sancharnet.in) : Evolution of Tin-Tungsten and Copper bearing hydrothermal solutions associated with Tosham igneous complex, Tosham, Bhiwani district, Haryana: a field inclusion study. J Geol Soc India 2006, 67(3), 379-86.

The Tosham granite/rhyolite is associated with tin- tungsten and copper mineralization. Tin-Tungsten and copper mineralization at the Tosham hill resulted from hydrothermal fluids of high to low salinity that were active over a temperature range of 150° to 450°C. Within this period, records of three stages of fluid activity were preserved in fluid inclusions. The first stage is characterized by high temperature (300° to 450°C) and high salinity (<62>37 wt% NaCl) fluids. In the second stage fluid temperature ranges 260ø to 380<144><144>

4 illus, 1 table, 28 ref

006330   Singh S;Patra B A;Vijan A R;Jain A K (Earth Sci Dep, Indian Inst of Technol Roorkee, Roorkee-247 667) : Biotite Rb-Sr ages : constraints on exhumation of the Karakoram metamorphic complex, eastern Ladakh. J Geol Soc India 2006, 67(1), 27-31.

Biotite and K-feldspar Rb-Sr ages from three granitoid intrusives within the Karakoram Metamorphic Belt (KMB), eastern Ladakh yield indistinguishable ages between 12-10 Ma. Since the closure of biotite for Sr diffusion is 300±50°C, interpreted these ages due to exhumation at 10 to 7 km depth within the crust. This implies that the Pangong Metamorphic Belt of the KMB, located at the southern termination of the Eurasian Plate, was undergoing a fast exhumation in a transpressional regime during Middle Miocene. These data also indicte that the southern edge of the Eurasian Plate has exhumed rapidly in comparison to the Higher Himalayan Crystallines within the Indian Plate segment.

^ssc4 illus, 3 tables, 32 ref

006329   Singh S;Claesson S;Jain A K;Gee D G; Andreasson P G;Manickavasagam R M (Dep of Earth Sci, Indian Inst of Technol Roorkee, Roorkee-247 667, Email: sandpfes@iitr.ernet.in) : 2.0 Ga granite of the lower package of the higher Himalayan crystallines, Maglad Khad, Sutlej valley, Himachal Pradesh. J Geol Soc India 2006, 67(3), 295-300.

Along the Sutlej valley, the lower package of the Higher Himalayan Crystalline (HHC) exposes a small concordant to discordant intrusive grey granite - The Maglad Khad Granite, within garnet mica schist/banded gneiss of the Jeori Formation. This body is fine grained and foliated along the margins, whereas the central part is relatively undeformed. This body along with aplites and pegmatites intrudes the country rock during early to syn-D₁ deformation. This is later affected by the most pervasive D₂-deformation producing gneissosity within the granite. U-Pb dating of zircons by conventional isotopic dilution technique yield an upper intercept age of 2068±5 Ma (2σ) from 6 zircon-fractions with MSWD=0.93, constraining the age of crystallization in the basal parts of the HHC during Early Proterozoic as well as the constraining pre-Himalayan fabric development.

^ssc3 illus, 2 tables, 38 ref

006328   Singh L N;Gupta D;Ram Gopal;Radhe Shyam;Singh S K;Singh S L;Agrawal A K (NO, Geol Surv of India Nth Region, Lucknow-226 024) : Mise-a-la-masse technique in planning the exploratory drilling for basemetal exploration in Sawar belt, Ajmer district, Rajasthan. J Geol Soc India 2006, 67(1), 83-91.

A small deposit of lead and zinc was established in southern part of Sawar metasedimentary belt during third pahse of drilling. The ise-a-la-masse survey, a post discovery geophysical method carried out in the boreholes of this blet has yielded significnat results. This method has been useful in delineating the subsurface disposition of mineralised zones and their lateral extension. This technique is also successful in the area in establishing correlation between different parts of an ore body with varying sulphide percentage, which are located distantly but are in electrical continuity. Hence the mise-la-masse method has been of immense help in planning the boreholes thereby optimizing drilling cost in the Sawar Belt. The composite map of equipotential line and chargeability contour has indicated that the contour pattern and disposition of anomaly axes are similar in both the cases.

9 illus, 1 table, 28 ref

006327   Sharma S K;Singh Chandel C P (Chem Dep, Univ of Jaipur, Jaipur-302 014) : Qualitative aspects of groundwater for drinking purpose of Bassi block of Jaipur district (Rajasthan). Aquacult 2006, 7(1), 61-72.

Jaipur (longitude : 95° 24' E; latitude : 27° 18' N), a city located at the central part of Rajasthan, is undergoing rapid urbanization and industrialization. The area under study was villages of Bassi block of Jaipur district. Groundwater samples from hand pumps of twelve sampling points of two consecutive years were analyzed during pre-monsoon, monsoon and post-monsoon session (May, 2003 to April, 2005) with the help of standard methods of APHA from the observations, it may inferred that the concentration of K⁺, Ca²⁺, Mg²⁺, SO₄^2-, CO^2-₃, HCO₃-, TH, DO, COD and BOD are within permissible standard limits but more than half of the studied samples were high in pH, EC, TDS, Na⁺, NO₃^-, Cl^-, F^- and RSC, which suggest the poor water quality in these water samples. Concentrations of all heavy metals like Co, Cd, Cu, Fe, Mn, Pb, and Zn were within permissible limits of ISI, ICMR and WHO. The study was the core to charactrize the groundwater in the village if Bassi block of Jaipur city and to assess suitability for drinking and domestic purpose.

5 tables, 25 ref

006326   Sharma M D;Garg N (Math Dep, Kurukshetra Univ, Kurukshetra-136 119, Email: mohan_here@rediffmail.com) : Wave velocities in a pre-stressed anisotropic elastic medium. J Earth Syst Sci 2006, 115(2), 257-65.

Modified Christoffel equations are derived for three-dimensional wave propagation in a general anisotropic medium under initial stress. The three roots of a cubic equation define the phase velocities of three quasi-waves in the medium. Analytical expressions are used to calculate the directional derivatives of phase velocities. These derivatives are, further, used to calculate the group velocities and ray directions of the three quasi-waves in a pre-stressed anisotropic medium. Effect of initial stress on wave propagation is observed through the deviations in phase velocity, group velocity and ray direction for each of the quasi-waves. The variations of these deviations with the phase direction are plotted for a numerical model of general anisotropic medium with triclinic/monoclinic/orthorhombic symmetry.

3 illus, 27 ref

006325   Sarkar A;Kshatriya J;Satheesan K (Meterology & Oceanography Grp Space Applics Cent, ISRO, Ahmedabad-380 015, Email: sarkar_abhi2000@yahoo.com) : Auto-correlation analysis of wave heights in the Bay of Bengal. J Earth Syst Sci 2006, 115(2), 235-7.

Time series observations of significant wave heights in the Bay of Bengal were subjected to auto-correlation analysis to determine temporal variability scale. The analysis indicates an exponential fall of auto-correlation in the first few hours with a decorelation time scale of about six hours. A similar figure was found earlier for ocean surface winds. The natue of variation of auto-correlation with time lags was also found to be similar for winds and wave heights.

2 illus, 4 ref

006324   S Chandra;S Atal;Murthy N S K;Subrahmanyam K; Rangarajan R;Reddy D V;Nagbhushanam P;Murthy J V S;Ahmed S;Dimri V P (NO, Natn Geophys Res Inst, Hyderabad-500 007, Email: shakeelahmed@ngri.res.in) : Oozing of water in parts of Andhra Pradesh, India. Curr Sci 2006, 90(11), 1555-60.

Oozing of water and rise in water level were reported by villagers and media during the third week of January 2005, in parts of Rangareddy, Nalgonda and Mahboobnagar districts of Andhra Pradesh. The event also coincided with the aftermath of the 9.3 magnitude earthquake in Sumatra, Indonesia and the tsunami in the Indian Ocean. The villagers and State and Central agencies were baffled by the unusual phenomenon. After a general reconnaissance, an integrated study comprising water-level monitoring, water quality analyses, topography survey, isotopic analyses, mise-a-la-masse survey and electrical resistivity imaging (ERI) was carried out at two sites near Mukindapur and Devanur of Yalal mandal in Ranga Reddy district, where the phenomenon of water-oozing was observed. The integrated study revealed that the oozing of water at the studied location is purely hydrological/hydrogeological and a shallow phenomenon. Scientific data could not attribute any strong connection to the deeper tectonics nor to the impact of the Sumatra earthquake and aftershocks. However, investigations form a prelude to any such geogenic activity in the region, suggesting monitoring of water level and further studies during the current hydrological year for any definite conclusion.

5 illus, 1 table, 14 ref

006323   Rau T K (NO, Geol Surv of India SR, Hyderabad-560 068) : Incidence of diamonds in the beach sands of the Kanyakumari coast, Tamil Nadu. J Geol Soc India 2006, 67(1), 11-16.

Micro- and macro-diamonds were recovered and studied from the heavy mineral concentrates of beach samples from the southern tip of India. Ranging in size from 0.30 mm x 0.30 mm to 1.50 mm x 2.05 mm, the diamonds are the modifed forms of octahedron, dodecahedron and cube and their combinations. Bigger sizes are presented by the broken / cleaved fragments. The diamonds exhibit varied tints of which white, pink and yellow are prominent. This is the second report of diamonds from the beach sands of India and the first of its kind from the Kanyakumari coast with charnockite and khondalite suites of rocks exposed in the hinterland, which shows an important structural grain in the form of the WNW-BSE trending Achankovil shear zone passing close to the present occurrence. The possible ultra-high pressure metamorphic and shock origins of these diamonds in SGT are discussed.

^ssc2 illus, 1 table, 25 ref

006322   Rajesh H M (Grad Sch of Life and Envir Sci, Univ of Tsukuba, Ibaraki-305-8572, Japan, Email: rajesh.hm@gmail.com) : Correct nomenclature for the Angadimogar pluton, Kerala, southwestern India. J Earth Syst Sci 2006, 115(2), 239-48.

The proper usage of modal composition and geochemical classification of granitoids has been discussed for assigning a proper nomenclature for the Angadimogar pluton, Kerala, southwestern India. This discussion is mainly aimed at addressing questions concerning the nomenclature of Angadimogar pluton (syenite vs. granite). Modal composition and whole-rock XRD data clearly show that the pluton exposed near Agadimogar is a quartz-syenite and its geochemistry is typical of a ferroan, metaluminous, alkali (A-type) granitoid.

5 illus, 1 table, 31 ref

006321   Raiverman V (NO, , 708 Maitri Apartment, 255 NSC Bose Road, Kolkata-700 047, Email: raiverman_v@rediffmail.com) : Himalayan elevation - somnolence to hyperactivity. J Geol Soc India 2006, 67(1), 21-5.

Efficacy of multiple-probe investigations in solving complex geological problems has been illustrated. The Cenozoic is the era of Alpine-Himalayan orogeny and the uplift pattern is one of long somnolence followed by brief hyperactivity. Nowhere else has this pattern been studied in greater detail than perhaps in the Himalaya. Classical stratigraphy, fossil records of flora and fauna, and sedimentologic, paleoclimatic and geomorphologic data offer ample evidence in this direction. Modern techniques of radiometric geochronology ofthe Himalayan crystallines also support this contention.

^ssc2 illus, 33 ref

006320   Rai D C;Murty C V R (Civ Engng Dep, Indian Inst of Technol, Kanpur-208 016) : Effects of the 2005 Muzaffarabad (Kashmir) earthquake on built. Curr Sci 2006, 90(8), 1066-70.

10 illus, 4 ref

006319   Radhakrishna B P (NO, , , Email: eiocind@gmail.com) : Diamond exploration in India. J Geol Soc India 2006, 67(3), 283-8.

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006318   Radhakrishna B P (NO, , , Email: gsocind@gmail.com) : The quake that shook Kashmir : has it any lesson to teach us?. J Geol Soc India 2006, 67(1), 5-10.

2 illus

006317   Paul D K;Nayak S S;Pant N C (Dep of Geol, Presidency Coll, College Street, Kolkata-700 073, Email: dalimpaul@yahoo.co.in) : Indian kimberlites and related rocks: petrology and geochemistry. J Geol Soc India 2006, 67(3), 328-55.

Potassic, ultrapotassic, ultramafic rocks occur mostly as dykes and few diatremes in the southern and central Indian cratons. The ultramafic diatreme in Majhgawan in central India is the only diamond-producing primary source at the present time. Several occurrences in southern India also contain diamond hut are not being commercially exploited. Available isotopic age data on these rocks suggest a Proterozoic age, a feature that is distinctive compared to other ages on similar rocks barring the Premier pipe in southern Africa. Petrographic, mineralogical and geochemical data on carefully selected samples from several localities has been presented. Mineralogically there are differences in the content of olivine, phlogopite, perovskite and spinel among the localities, in common with occurrences elsewhere, the olivines show a range from 83 to 93 mole percent. The macrocrystal olivines are more magnesian. Among the phlogopites, a two-fold division on the basis of Mg number is discernible. Most of the ilmenites are distinctly less magnesian than the southern African kimberlites. Geochemically the samples show a wide variation in major element abundances. Despite geographical separation and petrographic differences, Zr and Hf maintain a perfect positive correlation. In common with similar rocks, all the samples studied show an enrichment of both compatible and incompatible elements. Compared to established and accepted kimberlites of southern Africa and lamproites of Western Australia, the Indian samples show general similarity but also divergences in geochemical parameters. This is believed to suggest a transitional nature of the Indian potassic, uitralmafic rocks between kimberlites and lamproites. Petrogenesis of the occurrences is discussed.

17 illus, 13 tables, 59 ref

006316   Parthasarathy G;Sreedhar B;Chetty T R K (NO, Natn Geophys Res Inst, Hyderabad-500 007, Email: gpsarathy@ngri.res.in ) : Spectroscopic and X-ray diffraction studies on fluid deposited rhombohedral graphite from the Eastern Ghats Mobile Belt, India. Curr Sci 2006, 90(7), 995-1000.

First experimental results on the laser Raman spectroscopic, powder X-ray diffraction (XRD) and X-ray photoemission spectroscopic and high-temperature differential thermal analysis studies on graphite from the Burugubanda-Tapasikonda shear zone in the Proterozoic Eastern Ghats Mobile Belt (EGB) of Andhra Pradesh, India. Crystallinity, inter-planar spacing and unit-cell parameters were determined by powder XRD. Powder XRD studies on the graphite samples from the shear zone show all the strong XRD peaks corresponding to syngenetic (hexagonal) graphite and additional peaks at 0.208 and 0.197 nm corresponding to the presence of epigenetic (rhombohedral) polytype of graphite. On the basis of the intensity ratio of the (101) diffraction peaks for both syngenetic and epigenetic phases, the content of epigenetic phases within this sample is estimated to be up to 20-25%. The presence of epigenetic phase indicates that the Burugubanda shear zone contains fluid-deposited graphite, a solid carbon from natural carbon-bearing fluids such as those containing CO₂, CO and CH₄. The fluid-deposited nature of the graphite has also been confirmed independently by X-ray photo-electron spectroscopic studies. Laser Raman spectroscopic studies on all the samples show Raman bands at 1581 to 1585 cm^-1 (ordered peak), 1351 to 1355 cm^-1 (disordered peak) and second order peak at 2724 cm^-1. The intensity ratio of ordered to disordered peaks (0.09 to 0.10) indicates the peak metamorphic temperature of the host rocks corresponding to sillimanite zone. The values of interplanar spacing d002 (0.3346 nm), crystallite size (or stacking height; 54.83 nm) and degree of graphitization (135.5) indicated the peak metamorphic temperature of the host rock to be about 750 ± 30°C, and hence the high temperature that prevailed along the EGB shear zone.

6 illus, 28 ref

006315   Pant R K;Juyal N;Basavaiah N;Singhvi A K (Phys Res Lab, , Navrangpura, Ahmedabad-380 009, Email: navin@prl.ernet.in) : Late quaternary glaciation and seismicity in the higher Central Himalaya: evidence from Shalang basin (Goriganga), Uttaranchal. Curr Sci 2006, 90(11), 1500-5.

Shalang basin, which is a tributary basin of the Goriganga in the higher central Himalaya, is endowed with record of late Quaternary glaciation and seismicity. Three distinct glaciation events in the form of lateral moraines have been identified and are used to reconstruct the palaeo-Equilibrium Line Altitudes (ELA). Maximum ELA depression (<126> 600 m) was associated with the oldest and longest Stage-I glaciation. Subsequent glacial advancements were limited in extent and remained above 3500 m. Luminescence dating of glaciogenic sediments suggests that the oldest Stage-I glacial event is equitable to Marine Isotopic Stage-4 (MIS-4), whereas stages-II and III are assigned MIS-2 and little ice age respectively. Morphology of the moraines and presence of seismites in a lake sequence suggest tectonic activity along the Trans-Himadri Fault during the late Quaternary.

9 illus, 1 table, 23 ref

006314   Pandey P C;Khare N;Sudhakar M (Dep of Ocean Dev, Natn Cent for Antarctic and Ocean Res, Headland Sada, Vasco-da-Gama, Goa-403 804, Email: pcpandey@ncaor.org) : Oceanographic research: Indian efforts and preliminary results from the Southern Ocean. Curr Sci 2006, 90(7), 978-83.

Indian pilot expedition to Southern Ocean was launched by the National Centre for Antarctic and Ocean Research, Goa in January 2004. During this expedition a number of studies/experiments such as atmospheric observations, physical oceanographic observations, biological studies and chemical oceanographic observations were undertaken. In addition, to understand and reconstruct palaeoclimatic conditions in this part of the world, a number of surface and sub-surface sediment samples were collected along a north-south transect from 9.69°N to 55.01°S between 80 and 40°E long. The preliminary results of these studies in varied fields has been presented. These efforts of Indian scientists on Southern Ocean oceanography have yielded valuable data. The encouraging results have their bearing on the understanding and reconstruction of the glacial hydrography, sea ice extent and changes (if any) in the position of the palaeo front during the Holocene and the LGM over this sector of the Southern Ocean.

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006313   Pandey O P;Rao V K (NO, Natn Geophys Res Inst, Uppal Road, Hyderabad-500 007, Email: vijay_k_rao@ngri.res.in) : Missing granitic crust (?) in the Godavari Graben of Southeastern India. J Geol Soc India 2006, 67(3), 307-11.

Detailed analysis of seismic signatures of the Godavari graben together with available geological and geophysical informations suggests that the granitic crust, especially in the axial part of the graben, may be altogether missing. There is a possibility that Gondwana sediments rest directly over the granulitic basement.

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006312   Nigam R;Saraswat R;Kurtarkar S R (Micropaleontology Lab Geol Oceanography Div, Natn Inst of Oceanography, Dona Paula-403 004, Email: rajeev@darya.nio.org) : Laboratory experiment to study the effect of salinity variations on Benthic foraminiferal species - Pararotalia nipponica (Asano). J Geol Soc India 2006, 67(1), 41-6.

Culture experiment has been carried out to observe the response of Pararotalia nipponica (Asano) to different salinities and its salinity tolerance limits. The specimens of P. nipponica kpet in 33% saline water achieved optimum growth, while rest of the specimens maiantained under either higher or lower salinities showed comparatively lower growth. Pararotalia nipponica specimens kept at 10% and 15% salinity started becoming opaque and later their test dissolved, within a span of 25 days. Towards the end of experiment in order to find the maximum salinity tolerance limit, the salinity was gradually increased to 100%o, in the cultuer dishes having specimens at 40%o saline water and it was noted that P. nipponica specimens were alive even at 100%o salinity. It is concluded that comparatively lower salinities are much more detrimental to the foraminiferal tests than higher salinities. Results are significant as the salinity response of benthic foraminifera is being used for enviornmental assessment.

3 illus, 1 table, 24 ref

006311   Neetu S;Shetye S;Chandramohan P (Phys Oceanography Div, Natn Inst of Oceanography, Dona Paula-403 004, Email: neetu@nio.org) : Impact of sea breeze on wind-seas off Goa, west coast of India. J Earth Syst Sci 2006, 115(2), 229-34.

After withdrawal of the Indian Summer Monsoon and until onset of the next monsoon, i.e., roughly during November-May, winds in the coastal regions of India are dominated by sea breeze. It has an impact on the daily cycle of the sea state near the coast. The impact is quite significant when large scale winds are weak. During one such event, 1-15 April 1997, a Datawell directional waverider buoy was deployed in 23 m water depth off Goa, west coast of India. Twenty-minute averaged spectra, collected once every three hours, show that the spectrum of sea-breeze-related `wind-seas' peaked at O.23±0.05 Hz. These wind-seas were well separated from swells of frequencies less than 0.15 Hz. The TMA spectrum (Bouws et al 1985) matched the observed seas spectra very well when the sea-breeze was active and the fetch corresponding to equilibrium spectrum was found to be 77±43 km during such occasions. Emphasized on the diurnal cycle of sea-breeze-related sea off the coast of Goa and write an equation for the energy of the seas as a function of the local wind.

6 illus, 9 ref

006310   Narayanpethkar A B;Vasanthi A;Mallick K (Geol Dep, Solapur Univ, Solapur, Maharashtra) : Electrical resistivity technique for exploration and studies on flow pattern of groundwater in multi-aquifer system in the basaltic terrain of the Adila basin, Maharashtra. J Geol Soc India 2006, 67(1), 69-82.

More than 250 resistivity soundings with Wenner array have been conducted in the basaltic terrain of the Adila basin with area of about 585 sq. km around Solapur, Maharashtra. The resistivity sounding curves have been interpreted in two pahses. first, by curve matching and later by computer-aided techniques. Some of the sounding points were chosen near the existing boreholes so as to correlate the sounding results with the borehole lithologs. The potential zones for groudnwater accumulation in different horizons were identified by preparing the structure contour maps for the first, second and third interfaces and correlating them with geology and water table contour maps. The earth-sections obtained by interpreting the resistivity soundings are shown as three profiles along NE-SW, NW-SE and E-W directions. The numbers of successful borewells in different villages are also shown in these profiles. In all, 100 locations for the purpose of irrigation were recommended for drilling and 85 of them proved successful.

13 illus, 1 table, 19 ref

006309   Murty T S;Rao A D;Nirupama N;Nistor I (Dep of Civ Engng, Univ of Ottawa, Ottawa, Canada, Email: adrao@cas.iitd.ernet.in) : Numerical modelling concepts for tsunami warning systems. Curr Sci 2006, 90(8), 1073-81.

Since the four global oceans are not simply connected in the hydrodynamic sense, separate tsunami warning systems are needed for each ocean. Each ocean shows somewhat different tsunami characteristics, and for this reason, numerical models that are required for the tsunami warning system, also have to be different. These differences stem from whether an ocean gives rise to ocean-wide tsunamis or just to local tsunamis, and also the role played by boundary reflections. Using the concept of method of characteristics it is shown that the hyperbolic, parabolic, elliptic and parabolic-elliptic approaches are respectively valid for the Pacific, Atlantic, Indian and Arctic oceans.

4 illus, 1 table, 28 ref

006308   Murthy K S R;Subrahmanyam A S;Murty G P S; Sarma K V L N S;Subrahmanyam V;Mohan Rao K;Suneetha Rani P;Anuradha A;Adilakshmi B;Sri Devi T (NO, Natn Inst of Oceanography Regional Cent, 176, Lawsons Bay, Visakhapatnam-530 017, Email: ksr@nio.org) : Factors guiding tsunami surge at the Nagapattinam-Cuddalore shelf, Tamil Nadu, east coast of India. Curr Sci 2006, 90(11), 1535-8.

Tamil Nadu margin, in particular the Nagapattinam-Cuddalore shelf was the worst affected by the tsunami surge and inundation caused by the great Sumatra earthquake of 26 December 2004 (M_w 9.3). Surge heights in this part were of the order of 2 to 5 m, with inundation of the order of few hundred metres into the interior coast, thus causing huge loss of human life and property. Several reasons were attributed to the unusual surge in this part of the Tamil Nadu margin, the main reason being its relative proximity to the origin of the event, apart from the concave nature of the shelf with a gentle gradient. A detailed analysis of geophysical data of the Nagapattinam-Cuddalore shelf is presented. The results indicate that the structure of the underlying basement, the morphology and the land-ocean tectonics are the main guiding factors for the run-up heights in case of the Nagapattinam-Cuddalore shelf. The fault-controlled basement structure, and a straight coastline with narrow and gentle shelf have helped in rapid transgression of the surge inundating the coastal area.

3 illus, 18 ref

006307   Mohapatra M;Mohanty U C (India Meteorological Dep, , Guwahati-781 015, Email: mohanty@cas.iitd.ernet.in) : Spatio-temporal variability of summer monsoon rainfall over Orissa in relation to low pressure systems. J Earth Syst Sci 2006, 115(2), 203-18.

The summer monsoon rainfall over Orissa occurs mostly due to low pressure systems (LPS) developing over the Bay of Bengal and moving along the monsoon trough. A study is hence undertaken to find out characteristic features of the relationship between LPS over different regions and rainfall over Orissa during the summer monsoon season (June-September). For this purpose, rainfall and rainy days over 31 selected stations in Orissa and LPS days over Orissa and adjoining land and sea regions during different monsoon months and the season as a whole over a period of 20 years (1980-1999) are analysed. The principal objective of the study is to find out the role of LPS on spatial and temporal variability of summer monsoon rainfall over Orissa. The rainfall has been significantly less than normal over most parts of Orissa except the eastern side of Eastern Ghats during July and hence during the season as a whole due to a significantly less number of LPS days over northwest Bay in July over the period of 1980-1999. The seasonal rainfall shows higher interannual variation (increase in coefficient of variation by about 5%) during 1980-1999 than that during 1901-1990 over most parts of Orissa except northeast Orissa. Most parts of Orissa, especially the region extending from central part of coastal Orissa to western Orissa (central zone) and western side of the Eastern Ghats get more seasonal monsoon rainfall with the development and persistence of LPS over northwest Bay. While the seasonal rainfall over the western side of the Eastern Ghats is adversely affected due to increase in LPS days over west central Bay, Jharkhand and Bangladesh, that over the eastern side of the Eastern Ghats is adversely affected due to increase in LPS days over all the regions to the north of Orissa. There are significant decreasing trends in rainfall and number of rainy days over some parts of southwest Orissa during June and decreasing trends in rainy days over some parts of north interior Orissa and central part of coastal Orissa during July over the period of 1980-1999.

10 illus, 6 tables, 19 ref

006306   Mitchell R H (Dep of Geol, Lakehead Univ, Thunder Bay, Ontario, Canada P7B 5E1, Email: rmitchel@lakeheadu.ca) : Potassic magmas derived from metasomatized lithospheric mantle: nomenclature and relevance to exploration for diamond-bearing rocks. J Geol Soc India 2006, 67(3), 317-27.

Petrological studies have shown that each lamproite province has unique mineralogical and geochemical characteristics. These differences result from the differing metasomatic histories of the source rocks within individual cratons and accreted mobile belts. Orangeites are considered to represent the expression of potassic magmatism in the Kaapvaal craton and to have similar sources and origins to lamproites. The unique cratonic metasomatic history, perhaps coupled with distinct asthenospheric contributions as the impetus for magma genesis, of each potassic province explains why it is difficult to classify some potassic rocks occurring in the Sao Francisco, Aldan and Dharwar cratons as lamproites, orangeites or kamafugites. As the magmas from which these rocks crystallized are the unique expression of potassic magmatism in a particular craton they cannot, by definition, be classified according to schemes devised for potassic magmas in other provinces. Inter-provincial similarities arise because of the common physicochemical character of the metasomatic process in the lithospheric mantle. The differences reflect variations in the ages and modes of the metasomatic veins coupled with differing degrees of partial melting and/or asthenospheric contributions to the magmas. Any given craton can contain both kimberlites and potassic rocks. Rocks in each potassic province could in theory be given its own terminology, which taken to an extreme could lead to a proliferation of cratonic type-locality names. Alternatively, all of these diverse magmas might be collectively termed the metasomatized lithospheric mantle magma group (or MLM magmas). The mineralogical-genetic approach to classification implies that none of the MLM magmas are transitional to kimberlite magmas and that use of the portmanteau term "kimberlite clan rocks" for diverse diamondiferous rocks of different genesis is inappropriate for both scientific and economic purposes. The diamond potential of each province of potassic rocks must assessed independently as this will also reflect the unique geological history of the parental lithospheric mantle. Correct classification of potentially diamondiferous rocks is essential as this has implications with respect to exploration for, and evaluation of. particular intrusions using heavy mineral indicator suites and/or geophysical methods.

8 illus, 34 ref

006305   Misra S (Dep of Geol and Geophysics, Indian Inst of Technol, Kharagpur-721 302, Email: saumitra_misra@yahoo.co.uk) : Precambrian chronostratigraphic growth of Singbhum-Orissa craton, eastern Indian shield: an alternative model. J Geol Soc India 2006, 67(3), 356-78.

Available geological and radiometric age data suggests that Chotanagpur Gneissic Complex was evolved from a supracrustal precursor, some of them were formed at least before <126>2.3 Ga. The Singhbhum Group supracrustals and adjacent Chotanagpur Gneissic Complex perhaps had evolved from a common sedimentary precursor along with volcanics, which were deposited in a marine basin that existed at the present north of Singhbhum-Orissa craton during late Mesoarchaean period. The syn-rift sedimentary assemblage of the Singhbhum Group was deposited along the margin of Singhbhum-Orissa craton, whereas the post-rift stable shelf sedimentary precursor of the Chotanagpur Gneissic Complex was deposited towards further north. In the Neoarchaean period between <126><62>3.09 Ga and <126>2.5 Ga the nature of deformation along the marginal part of Singhbhum-Orissa craton was extensional type. In the following Palaeo- to Mesoproterozoic period, the protolith of Chotanagpur Gneissic Complex grew in sequence between <126><62>2.3 and 1.0 Ga through two time-separated supracrustal-granite cycles where the firsthand second cycles ended at <126>1.60 and 1.00 Ga respectively. Radiometric ages suggest that Chotanagpur Gneissic Complex along with Singhbhum Group experienced major magmato-metamorphic activities during Palaeo- and Mesoproterozoic periods at <126>2.5 or <62>2.3 Ga, 1.6 Ga, 1.0 Ga and 0.9 Ga. During this period Singhbhum-Orissa craton recorded basic volcanism (Jagannathpur and possibly Malangtoli volcanics) at <126>2.25 Ga, followed by depostion of elastic sediments (Kolhan Group) and finally emplacement of mafic dykes and sills (Newer Dolerite) in three successive sequences at <126>2.0 Ga, 1.6 Ga and 1.0 Ga, where all these phenomena took place under anorogenic setting. The Singhbhum Shear zone, which marked a tectonic boudary between Singhbhum-Orissa craton and Singhbhum mobile belt to north, was reactvated several times during geological past, the oldest being at <126>3.09 Ga, followed by emplacement of soda granite pluton along this shear zone at <126>2.22 Ga, copper mineralization at <126>1.77 Ga, shearing at <126> 1.67-1.63 Ga, uranium mineralisation at <126>1.58-1.48 Ga and the final phase of shearing at <126>1.0 Ga.

3 illus, 3 tables, 112 ref