021510   Rahman M M;Islam M O;Hasanuzzaman M (Rajshahi Univ of Engineering and Technology, Rajshahi, Bangladesh) : Effective rainfall for irrigated agriculture in South-Eastern zone of Bangladesh. Green Fmg 2009, 2(5), 286-9.

Major source of water available either for agriculture or for human consumption is obtained from the rain that falls on the earth's surface. Agricultural production in Bangladesh is very much" dependent upon rainfall. But, not all the rain that falls on the earth's surface is useful for agricultural purpose. This study deals with "effective rainfall", i. e. the rainfall that directly satisfies crop water requirements. In this study four different methods have been used for estimating effective rainfall in Bangladesh. Effective rainfalls have been estimated for the ten meteorological stations of Bangladesh, covering South - Eastern part of the country. By using different climatological data, effective rainfall have been estimated for two crop growing seasons, one is kharif (July to October ) and the other is rabi (December to March). It has been observed that the values of effective rainfall percentage for kharif season varies from 13.94% at Teknafto 47.27% at Chandpur by Renfro Equation Method, from 18.79% at Teknaf to 46.33% at Chandpurby U. S. Bureau of Reclamation Method, from 52.94% at Sandwip to 100% at several stations by Potential Evapotranspiration/Precip/tation Ratio Method and from 22.58% at Teknafto 64.14% at Chandpur by U.S.D.A, SCS Method. Effective rainfall percentage for rabi season varies 63.30% at Chittagong to 76.79% at Maizdi Court by U.S.D.A, SCS Method and by other methods the values of effective rainfall percentage is near about 100%, It has been observed that as the distance from sea increases the value of effective rainfall percentage also increases. While designing an irrigation project, opt/mum utilization of irrigation water can be achieved by using the effective rainfall values.

1 table, 13 ref

021509   Raghumani Singh Y (PG Dep of Geology, University of Jammu, Jammu, Email: yengmani@rediffmail.com) : New record of palynological assemblage from eocene Ypresian of the Subathu formation Jammu. J Geol Soc India 2007, 70(1), 143-6.

In Jammu region, the Subathu Formation overlies unconformably the pre-Tertiary Sirban Limestone and is in turn overlain by the Murree Formation. The lower Tertiary deposits of Jammu region elicited considerable interest among geologists and paleontologists as they are expected to provide important insights into the India-Asia collision tectonic event. Though extensive micropalaeontological works have been carried out in this area, very few palynological studies have been undertaken until now. Additionally, in comparison to Jammu region, the Subathu sediments of Shimla Hills have been subjected to extensive palynological studies. Study records for the first time microforarniniferal linings and palynomorphs except dinocysts from the Subathu sediments ol):he Jammu region. The present palynological assemblages is significant as it provides additional data on palaeoenvironment of the Subathu Formation.

2 illus, 10 ref

021508   Purohit K K;Mukherjee P K;Saini N K;Rathi M S;Khanna P P (NO, Wadia Institute of Himalayan Geology, 33, Gen. Mahadeo Singh Road, Dehra Dun-248 001, Email: mukherjee_pk@wihg.res.in ) : Geochemical dispersion pattern of some heavy metals in upper Alaknanda catchment: application in mineral exploration and environmental implications. J Geol Soc India 2007, 70(1), 97-108.

Geochemical characteristics of active stream and river sediment from part of the main Alaknanda catchment includingmain tributaries (Nandakini Pindar and Mandakini) in Garhwal Himalaya were investigated. Economically important and environmentally sensitive selected trace element (Cr, Ni, Pb, Zn, Cu, Th and U) abundance in the sediments were studied to evaluate their spatial distribution in relation to lithotectonic control, mineral prospects and environmental geochemistry. Th background concentrations, as median values, are found perceptibly enriched for these elements with respect to upper crustal average. Distribution patterns of U, Th and Pb are distinctive and show intrinsic relationship with the medium-grade deformed rocks (granitoids) of central crystallines and are generally enriched, whereas Cu is depleted in the same area. Background concentration of Cr is many fold enriched as compared to crustal abundance. However, Ni in relation to Cr is not so high. There is a good correlation between Cr and Ni in the areas of mafic volcanic occurrences within low-grade metasedimentry rocks. But the same is not true in case of Nandakini valley within Baijnath central crystallines where Cr enrichment is anomalously high with Ni showing antagonistic relationship. High U and Th content in sediments are observed within or near the central crystalline thrust sheets, whereas the Cu and Zn anomaly zones are restricted within the Garhwal group of rocks. Some of these anomalies are significant and seems to have a definite structural (thrust/Fault) and lithological control, such as crystal lines for U and Th and carbonates for Cu and Zn. The present study, thus also provides some useful clues for mineral exploration.

4 illus, 2 tables, 43 ref

021507   Prasad S;Bagchi J (NO, Geological Survey of India, Faridabad-121 001, Email: bagchij@yahoo.com) : Aeolian sediment transport defined by grain size trends in part of Haryana. J Geol Soc India 2007, 70(4), 658-66.

Aeolian deposits occur extensively over the Ambala Older Alluvium in the southern and western part of Haryana. Delineating aeolian sediment transport pattern assists in characterising the aeolian environment and in understanding the evolution of the Thar Desert. Surface exposures of the Late Quaternary stabilised dunes do not exhibit primary structures based on which sediment transport direction can be inferred. In the study area trend surface analysis of mean, sorting and skewness shows statistically significant trends. Mean size and skewness with a linear trend decreases towards northeast. Sorting increases towards northeast, southeast and southwest. `Transport vector' analysis reveals a sediment transport pattern, with northeast and south as the two dominant directions of transportation.

5 illus, 2 tables, 24 ref

021506   Patel S J;Desai B G;Vaidya A D;Shukla R (Geology Dep, M.S. University of Baroda, Vadodara-390 002, Email: sjpatel_geol@rediffmail.com) : Middle jurassic trace fossils from Habno Dome, mainland Kachchh, western India. J Geol Soc India 2008, 71(3), 345-62.

Middle Jurassic rocks of the Habo Dome consist of well-preserved abundant trace fossil genera. These are described from the black limestone of Jhurio Formation and overlying thick clastic sequence which is capped by thin bands of oolitic limestone of Jumara Formation. Total 30 ichnospecies of 23 ichnogenera are identified and their preservational aspects, ecological observations, producers and behavioural aspects are discussed. The trace fossils are found in subtidal sequences i.e. sandstone-siltstone-shale partings, thick, massive and cross-bedded sandstones and in shelf sequences i.e. black limestone which consists of abundant Chondrites species with resting traces (Lockeia). The clastic sequence exhibits poorly sorted and intensely bioturbated cross-bedded sandstone, ripple-marked ferruginous sandstone and laminated shale-siltstone lithofacies which consist of three dimensional burrow systems of Ophiomorpha, Thalassinoides and Spongeliomorpha, feeding burrows (Rhizocorallium, Chondrites, Halymenidium, Gordia, Rutichnus, Planolites) and crawling traces (Scolicia, Gyrochorte). Massive sandstone facies is moderately bioturbated while shale, conglomerate, shell bed and oolitic limestone lithofacies are poorly bioturbated (Thalassinoides). Wave and current energy, substrate consistency, food supply and bathymetry may have influenced the distribution of trace fossils in the shallow marine environments of the Middle Jurassic rocks of the Habo Dome.

7 illus, 69 ref

021505   Pant C C;Paul A (Geology Dep, Kumaun University, Nainital-263 002, Email: ccpgeol@yahoo.com) : Recent trends in seismicity of Uttaranchal. J Geol Soc India 2007, 70(4), 619-26.

Seismic network in Kumaun Himalaya has recorded nearly three thousand earthquakes events since April 1999. The data has been analysed to study the seismicity pattern, seismicity rate, stress drop and focal depth pattern. The detailed analyses of 388 events have been carried out. The magnitude of the events is less than 4.2, the focal depth for most of the events lie between 10-25 km and the stress drop values are low. An attempt has been made to delineate seismically active zones and the seismicity pattern indicates that the strain energy is being released along NW-SE direction almost parallel to the regional thrust viz. Main Central Thrust / Munsiari Thrust / Berinag Thrust / North Almora Thrust and orthogonally along N-S / NNW-SSE directions. Considering the fact that the strain energy is continuously building up along the Himalayan front due to convergence of Indian and Eurasian Plates and the region lying between Bihar-Nepal border (1934 earthquake MS 8.4) and Kangra (1905, earthquake MS 8.6) has not experienced a major earthquake (M ≥8). The evaluated low value of seismicity rate and stress drop in the Kumaun Himalaya may be indicative of possible major earthquake in near future.

4 illus, 3 tables, 38 ref

021504   Niranjan Kumar S;Nagendra Babu G;Jeyagopal A V;Maithani P B (NO, Atomic Minerals Directorate for Exploration and Research, Dep of Atomi, Hyderabad-500 016, Email: dr_niranjan01@rediffmail.com) : Discovery of uranium mineralisation in sheared quartzite and associated crystallines in the environs of Pranhita-Godavari Basin, Mysemgutta, Kaddam area, Adilabad district, Andhra Pradesh. J Geol Soc India 2008, 71(3), 331-6.

Reconnaissance radiometric surveys in the northwestern parts of the western Pakhal belt in the Pranhita-Godavari Basin (PG basin), have led to the location of uranium anomalies for the first time in the environs of P-G Basin exclusively in the "older sheared fuchsite bearing quartzite" overlain by the Neo-Proterozoic Penganga sediments in the proxmity of their unconformity contact at Mysemgutta, Kaddam, district Adilabad, A.P. Surface mineralisation is manifested in the form of secondary uranium minerals associated mainly along the fractures in the fault zones. The quartzite assayed up to 0.23% U₃O₈ with negligible thorium (<0.005 %ThO₂). Follow up petrological and XRD studies of the rocks revealed the presence of primary uranium mineral uraninite (UO₂) in addition to secondary U-minerals in the form of ianthinite [U₆O₇(OH)₂₀], metatorbernite [Cu(UO₂)₂(PO₄)₂.8H₂O] and phosphuranylite [Ca(UO₂)₄(PO₄)₂(OH)₄.7H₂O], besides U+Ti phases/ brannerite [U,Ca,Ce)(Ti,Fe)₂O₆. Other ore minerals associated are chromite, pyrite, pyrrhotite and rutile. The discovery has opened up new vistas for seeking Proterozoic unconformity related uranium mineralisation at the base of Neo-Proterozoic Penganga sediments in the PG Basin, Andhra Pradesh.

6 illus, 2 tables, 12 ref

021503   Naithani A K (Geology Dep, H.N.B. Garhwal University, Post Box No 86, Srinagar (Garhwal)-246 174, Email: ajay_naithani@hotmail.com) : RMR - a system for characterizing rock mass classification: a case study from Garhwal Himalaya, Uttarakhand. J Geol Soc India 2007, 70(4), 627-40.

Rock mass and its properties for stability analysis several classification methods are available. The rock mass rating (RMR) has been found to be quite useful due to the ease with which it can be practiced and based mainly on the collection of field data and strength parameters. This technique has been used earlier in many mining and engineering projects and found useful in an assessment of the slope stability condition and for mining plans and designing the structures. RMR technique involves collection of data on rock strength, RQD (%), spacing of discontinuities, condition of discontinuities and groundwater conditions. Twelve sites selected on the basis of good exposures of the rock outcrops along the road section were studied using RMR approach. The results indicates that the rock mass of this area fall under the good, fair and poor rock quality. The rock type viz. mica schists and phyllites well exposed in the study area have lower RMR ratings, as they are more readily weathered and contain some weak planes and break along these planes. The analysis and evaluation should serve as a guide for engineering development projects in the area.

4 illus, 11 tables, 46 ref

021502   Mundepi A K;Kamal;Paul A (NO, Wadia Institute of Himalayan Geology, 33, General Mahadeo Singh Road, Dehra Dun-248 001, Email: akmundepi@wihg.res.in) : Estimation of site amplification at various litho-units in NW-Himalaya using horizontal to vertical ratio. J Geol Soc India 2007, 70(4), 605-9.

Survey was conducted in Kumaun Himalaya for the purpose of characterizing background seismic noise characteristics. Deals with the estimation of local site effects at various locations with varying geological and tectonic environments in the region. The effects of the various litho units on the site's predominant frequency are depicted here. It is seen that the character of the top sedimentary column and its compaction plays a vital role in the estimation of site response. The level of tectonic complexity is also reflected in the noise spectra of the studied regions. The region in close proximity of the MCT zone exhibits high background seismic noise level.

4 illus, 1 table, 9 ref

021501   Mukhopadhyay J;Ghosh G;Beukes N J;Gutzmer J (Dep of Geology, Presidency College, Kolkata-700 073, Email: joydip17@rediffmail.com) : Precambrian colluvial iron ores in the singhbhum craton: implications for origin, age of Bif-hosted high-grade iron ores and stratigraphy of the iron ore group. J Geol Soc India 2007, 70(1), 34-42.

Conglomerates correlatable with the late Meso-Neoproterozoic Kolhan Group in the vicinity of Cham and Baljori villages flanking the Iron Ore Group of rocks of the Jamda-Koira valley, Jharkhand and Orissa, in "pebbles of hard high-grade iron ore, which are mined as iron ore. The mode of occurrence and character of these "bearing conglomerates suggest them to have been deposited in a proximal alluvial fan setting. The iron ore pebbl composed of martite and microplaty hematite, and are very similar in appearance to the BIF-hosted iron ores Noamundi-Joda deposits of the Iron Ore Group. The ore-bearing conglomerates provide evidence that the hard he rich iron ores of the western Iron Ore Group, from which ore pebbles are most probably derived, must have preda Kolhan sedimentation and are not related to modern lateritic weathering.

3 illus, 52 ref

021500   Molnar P (Geological Sciences Dep, Cooperative Institute for Research in Environmental Sciences (CIRES),, Boulder, Colorado 80309-0399 USA, Email: peter.molnar@colorado.edu) : Examination of evidence used to infer late cenozoic "uplift" of mountain belts and other high terrain: what scientific question does such evidence pose?. J Geol Soc India 2007, 70(3), 395-410.

Virtually every mountain belt and high plateau, as well as for many topographically minor features, a credible, if not outstanding, geologist has asserted that that high terrain rose abruptly in Pliocene and/or Quaternary time. Such suggestions rely on a variety of observations that include paleobotanical finds of plant organs resembling those of taxa that now live lower, recent increases in exhumation, erosion, incision, and/or sediment-accumulation rates, "juvenile landscapes," and in some cases no supporting data at all (presumably because the inference has become so widely accepted that supporting evidence is no longer needed). Regions of allegedly recent "uplift" include obviously active belts like the Himalaya and seemingly tectonically dead terrain such as Transantarctic Mountains of Antarctica, the Rocky Mountains of the Western USA, or any part of Australia, as well as belts, like the western Alps, which might be called senile, if not dead yet because rigor mortis has not yet set in. The lack of a globally synchronous change in rates of plate motion in the past few million years denies any suggestion of a globally synchronous, coordinated rise of high terrain a sensible tectonic cause. Thus, although not all inferences of recent increases in mean elevations (or whatever has been meant by the word "uplift") need be false, most surely are. Global climate change offers the only globally synchronous process that could mislead so many geologists to infer a recent rise of high terrain. Deciphering how climate change forged a tectonic signature on the landscape remains a challenge for geomorphologists and tectonic geologists alike.

1 table, 7 ref

021499   Mishra S;Deo S;Rajaguru S N (Archaeology Dep, Deccan College, Pune-411 006, Email: sheila.mishra@gmail.com) : Some observations on laterites developed on Deccan trap: implications for post-Deccan trap denudational history. J Geol Soc India 2007, 70(3), 521-5.

Earlier workers have classified the lateritized surfaces into two groups - one showing a conformable relationship and the other an unconformable relationship to the Deccan trap. The first surface occurs at elevations varying between 1200 to about 1500 m asl in the Sahyadri range on the youngest Deccan Trap flows, while the second is found at elevations varying from 10-200 m asl in the narrow coastal plain to the west of the Sahyadris on lower (older) Deccan Trap flows. The observations of laterites in Pune, Raigarh and Satara and Sangli districts of Maharashtra within the Deccan Trap region however, show that the geomorphology of laterites in relation to the Deccan Trap is more varied than indicated in the model by Widdowson. Two major denudational surfaces on the Deccan Trap, at 600 m asl and 850 m asl have preserved remnants of a laterite cover which have implications for the denudational history of the Deccan Traps.

1 illus, 22 ref

021498   Mishra K S;Jagadeesan P;Pandey K K;Saxena V P;Sinha R M (NO, , , Email: mishra_ks03@yahoo.com) : REE geochemistry of uranium-bearing columbite-tantalites and multiple oxide phases from proterozoic rare metal pegmatites of Pandikimal and adjoining areas, Jharsuguda district, Orissa. J Geol Soc India 2008, 71(3), 313-20.

Rare earth element (REE) geochemistry of uranium bearing columbite-tantalite and multiple Nb-Ta oxide phases from the Pandikimal-Jangapara pegmatites, Jharsuguda district, Orissa have been studied and evaluated. Columbite-tantalite from these areas contain low ∑ REE (100-1000 ppm) with LREE/HREE_CN <0.5 and minor amounts of uranium (0.3-0.6%U₃O₈). Multiple oxide phases (yttrotantalite, samarskite, microlite and fergusonite) contain elevated amounts of U (10-11% U₃O₈) and REE (1.9-2.8%) with HREEβLREE. Plot of ∑REE vs chondrite-normalised LREE/HREE shows positive correlation in `U'rich multiple oxides compared to those from columbite-tantalites which tend to show a negative correlation. The LREE/HREE ratio is 0.24 with negative Eu anomaly (Eu/Eu* = 0.1) indicating evolved nature of these pegmatites.

7 illus, 2 tables, 15 ref

021497   Mishra D C;Rajasekhar R P (NO, National Geophysical Research Institute, Hyderabad-7, Email: dcm_ngri@yahoo.co.in) : Gravity and magnetic signatures of proterozoic rifted margins: Bundelkhand craton and Bijawar and Mahakoshal group of rocks and Vindhyan basin and their extension under Ganga basin. J Geol Soc India 2008, 71(3), 377-87.

Gravity highs surrounding Bundelkhand Craton and three sets of sub parallel paired aeromagnetic anomalies along its SE margin are attributed to high-density, high susceptibility volcano sedimentary sequences and mafic intrusives of Bijawar Group of rocks of Paleo-Proterozoic period. Modelling of airborne magnetic anomalies provide almost vertical intrusives of high susceptibility (1x10^-3 emu) mafic rocks at a depth of about 850 m below northern margin of Vindhyan sediments in the basement which is supported from high velocity rocks at the same depth in an adjoining seismic section. Both these anomalies are typical of those observed along rifted continental shelves world over as in case of western margin off India, Norway, Red Sea Rift, etc. Gravity highs and linear magnetic anomalies along southern margin of the Vindhyan basin are attributed to mafic and ultramafic intrusives of older Mahakoshal group of rocks with volcano sedimentary sequences of sectoral nature at the rifted margin of Bundelkhand craton similar to canyon deposits along present day continental rise and slope. The undisturbed Vindhyan sediments of Meso-Neo-Proterozoic period were deposited on the platform provided by continental shelf of Bundelkhand craton during convergence as fore land basin. This is in conformity with relative ages of Mahakoshals, Bijawars and Vindhyan sediments as they formed during rifting and convergence phases, respectively. Volcanic plugs (~1.11 Ga) associated with northern margin of Vindhyan basin (Panna diamond belt) and Mahakoshal Group of rocks (Jungel pipes) towards the south lying with in zones of high magnetic anomalies (mafic/ultramafic rocks referred to above) might be related to the same rifting process, but extruded to surface at later dates. Gravity high east of Aravalli Delhi Mobile Belt forming the Agra-Shahjahnpur ridge bounded by northward extensions of Great Boundary Fault and Chambal fault, is attributed to rocks equivalent to Mahakoshal Group of rocks along the western margin of the Vindhyan basin extending under the Ganga basin up to the Himalayan front in Western Nepal where seismically active zone of Western Himalaya starts.

7 illus, 41 ref

021496   Mathur V K;Ghosh A K;Misra P S;Kacker A K (Palaeontology Div, Geological Survey of India, Sector-E, Aliganj, Lucknow-226 024, Email: vinodmathur1954@rediffmail.com) : Record of cretaceous biota from shell limestone (Nilkanth formation) Mussoorie syncline, Lesser Himalaya, India. J Geol Soc India 2008, 71(3), 371-6.

Shell Limestone (Nilkanth Formation) of the Mussoorie Syncline, Lesser Himalaya, Uttaranchal, India has yielded varied biota i.e. bryozoa, echinoid radiole, hydrozoa, foraminifers, green algae and several casts of bivalve genera. Presence of Ceriocava nilkanthi Singh, 1980, a bryozoan recorded earlier from the Coralline Limestone of the Bagh Beds (Cretaceous) occurs in the Shell Limestone suggests Cretaceous age for the Nilkanth Formation. Sandy oolitic limestone with abundant rounded bioclasts of foraminifers and dasycladacean green algae indicate a shallow high energy marine environment for this formation. The Nilkanth Formation is unconformably overlain by bioturbated olive greenish grey ferruginous shale of the (?) Subathu Formation of Eocene age.

4 illus, 22 ref

021495   Luirei K;Bhakuni S S (NO, Wadia Institute of Geology, Northeast Unit, Itanagar-791 113, Email: ashing_luirei@rediffmail.com) : Landslides along frontal part of eastern Himalaya in east Siang and lower Dibang districts, Arunachal Pradesh, India. J Geol Soc India 2008, 71(3), 321-30.

Eastern Himalayan foothills particularly between Siang and Dibang Rivers are prone to landslides. The causative factors of landslides are steep slopes, presence of major structural discontinuities, multiple joint sets, drainage density, weathered to soft nature of rocks and heavy rainfall. Most of the landslides are taking place in steep to very steep slopes. Fault gouges and brecciated rocks developed along the Main Boundary Thrust (MBT) zone have also facilitated the initiation of many landslides. Wedge analyses for sandstones and quartzites have also been carried out to determine their influence on the slope stability and potential failure. The area is also susceptible to high rate of erosion due to structurally controlled streams and gullies resulting in profuse development of fans along the foothills. Seismic condition of the region is also a major concern for the slope stability. Landslides debris usually chokes the streams, destroy the bridges, subways and roads and affect cultivated lands particularly along the mountain front. Neotectonic activity along the MBT has resulted in the development of young and steep hill-slopes, which are prone to landslides.

7 illus, 1 table, 28 ref

021494   Kumaran K P N;Limaye R B;Nair K M;Padmalal D (Palaeobiology Group, Agharkar Research Institute, G G Agarkar Road, Pune-411 004, Email: kpnkumaran@hotmail.com) : Palaeoecological and palaeoclimate potential of subsurface palynological data from the late quaternary sediments of South Kerala sedimentary basin, southwest India. Curr Sci 2008, 95(4), 515-26.

The accrued palynological data obtained from the subsurface sediments of South Kerala Sedimentary Basin have been found to be useful for identifying various ecological complexes and their environmental preferences. The occurrence and relative abundance of Cullenia exarillata pollen along with other wet evergreen forest members at certain intervals are of great significance as they indicate the prevalence of heavy rainfall during Early Holocene. This aspect is further complemented by the presence of a large number of fungal remains. In contrast, their scarcity and even absence at higher levels in boreholes point towards relatively dry climate during Late Holocene. Another significant aspect of the palynological record is the occurrence of reworked pollen of Eugeissona (Areca-ccae) and Ctenolophon (Ctenolophonaceae) restricted to one or two intervals in the boreholes, as these forms are common in Miocene sediments of the Warkalli Formation. Increased organic matter in Late Quaternaries may be attributed to relatively higher rates of weathering and erosion of the hinterland as a result of enhanced SW monsoon during Late Pleistocene-Early Holocene. Diatoms and palynodebris, including non pollen palynomorphs (NPP) observed in palynological preparations are also found to be important for interpretation of the Late Quaternary climate of southwest India.

7 illus, 4 tables, 33 ref

021493   Khayingshing L;Bhakuni S S (NO, Wadia Institute of Himalayan Geology, NE Unit, Itanagar-791 113, Email: ashing_luirei@rediffmail.com) : Soft sediment deformational structures in the lacustrine deposits of ziro valley, lesser Himalaya, Arunachal Pradesh. J Geol Soc India 2007, 70(1), 73-8.

Soft sediment deformational structures of various types are preserved in the lacustrine deposits at Sora village ofZira valley, Lesser Himalaya, Arunachal Pradesh. The structures that have been observed include sand dykes, flame structures, load casts, micro-folds, convolute and other complex structures. The affected sediments are predominantly loosely packed cohesionless sands and silts due to change of state fram grain supported to fluid supported matrix by application of external force; and are enclosed between two undeformed layers. Earthquake induced liquefaction is proposed for the formation of such structures taking into consideration the geodynamic conditions of the region.

4 illus, 31 ref

021492   Kharak Singh;Radhakrishna M;Pant A P (E&P Div, Essar Oil Ltd, Mumbai-440 034, Email: kharaks@essar.com) : Geophysical structure of Western Offshore Basins of India and its implications to the evolution of the western ghats. J Geol Soc India 2007, 70(3), 445-58.

Western Ghats lies to the east of two prominent basins of western offshore viz. Mumbai offshore basin, Konkan-Kerala offshore basin. These basins have evolved in a divergent continental margin setting as a consequence of break up of Madagascar in Mid Cretaceous and Seychelles in Late Cretaceous from India. The basic framework of the Western Continental Margin of India was established by the end of Cretaceous. The Surat depression in the north and the Vengurla Arch in the south define Mumbai offshore basin. Shelf margin basin marks its western limit. The width of the shelf is ~230 km. The entire shelf from the coast towards the shelf margin zone is segmented by basement controlled NW-SE to N-S faults giving rise to many horst-graben features. The Konkan-Kerala basin located south of the Vengurla Arch has an average width of ~ 75 km. Eastern fringe of the basin extends to the land along the Kerala coast where outcrops of Miocene are preserved. In the west, a number of NNW-SSE trending Laxmi-Laccadive and Kori-Comorin ridges separated by depressions are identified. The basin is more differentiated in Eocene / Oligocene section with N-S trending horsts and grabens. The seismic data in the basins show prominent N-S fault trends. The data further indicate the presence of strike-slip movement and associated flower structures. Therefore, the geophysical and drilling data in the western offshore support a plate tectonic model for structural styles as a result of fragmentation initiated by transform faulting. The basins came into existence in late Cretaceous and evolved through Tertiary. Extensive lava flows at 65 Ma are attributed as a fissure type eruption through transform faults during Deccan volcanism. The Western Ghats may therefore, be the result of rifting and severe faulting with initial uplift and tilt to the east. The west coast of India was further elevated during the Tertiary in successive phases. The removal of vast quantities of rocks from the onshore, its deposition in the offshore basins and the associated flexural responses might have resulted in the present day Western Ghats escarpment.

9 illus, 46 ref

021491   Kale V S;Shejwalkar N (Geography Dep, University of Pune, Pune-411 007, Email: vskale@unipune.ernet.in) : Western Ghat escarpment evolution in the Deccan Basalt Province: geomorphic observations based on DEM analysis. J Geol Soc India 2007, 70(3), 459-73.

Examines selected aspects of river and basin morphometry in the western Deccan Basalt Province (DBP) to get a better insight into the style and rate of Western Ghat evolution. Various drainage basin morphological attributes were extracted from digital elevation model (DEM) constructed by using the ca. 90 m resolution Shuttle Radar Topographic Mission (SRTM) digital elevation data. The main findings that emerge from the analyses of the long profiles, basin shapes, length-area and slope-area relationships and escarpment sinuosity are: (i) there is a remarkable similarity in the shapes of the long profiles of the principal coastal rivers suggesting that the headward erosion and growth of the drainage in the Ghat zone has proceeded, more or less, uniformly, and the geomorphic or geologic conditions have not favoured any particular river, (ii) the coastal basins are more circular than expected, indicating that there is a tendency to increase the basin area laterally via tributaries, rather than longitudinally, and that the tributaries have also played a crucial role in the recession of the escarpment, (iii) the Konkan rivers are characterized by severe deepening in the upper-medial portion and dominance of fluvial processes in the headwater reaches, and (iv) the Ghat Escarpment sinuosity is relatively low, but not very distinct from the sinuosity of the basin divides on the Maharashtra Plateau, implying that the geomorphic processes that create and sustain steep slopes along the western continental margin and over the Maharashtra Plateau are fundamentally same. All the geomorphic evidences suggest that the tempo of Ghat Escarpment retreat is modest at best, and it seems that the Ghat scarp has receded maximum by a few kilometers.

11 illus, 37 ref

021490   Jeyagopal A V;Dhana Raju R;Maithani P B;Chaki A (NO, Atomic Minerals Directorate for Exploration and Research, Dep of Atomi, Begumpet, Hyderabad-500 016, Email: jeyagopalav@yahoo.com) : Cyclic sedimentation and classification of the Papaghni group of sediments, Cuddapah basin, Andhra Pradesh. J Geol Soc India 2008, 71(3), 363-70.

Mesoproterozoic Papaghni Group in the Cuddapah basin of southern Andhra Pradesh comprises mainly arenaceous, argillaceous and calcareous sediments. These sediments occur in sequences that are mappable on large scale (1:5000) and the sequences are identified by unconformities which are recognised by conglomerate/breccia beds in Vempalle Formation (Papaghni Group). Each sequence starts with near-shore arenaceous and argillaceous sediments, and ends up with relatively deeper marine chemical precipitate, viz. dolomitic sediment, with these three constituting one cycle of sediments. The thickness of each cycle ranges from about twenty meters to hundreds of meters and three such cycles of sedimentation are identified. On the basis of the identification of cyclic sedimentation and bounding unconformities, it is proposed that the Vempalle Formation of Papaghni Group may be classified into Lower, Middle and Upper members, which denote recurrence of similar depositional settings during the Vempalle sedimentation.

5 illus, 2 tables, 20 ref

021489   Jain S (Dep of Earth Sciences, Florida International University, Miami-33199, USA, Email: sjain002@flu.edu) : The Bathonian-callovian boundary in the middle jurassic sediments of Jaisalmer basin, western Rajasthan. J Geol Soc India 2007, 70(1), 79-89.

: Strictly localized collection of ammonites has helped demarcate the Bathonian-Callovian boundary in the Middle Jurassic outcrop of the Kuldhar section (Jaisalmer Basin). Latest Bathonian age has been assigned to the association of Sivajiceras congener (Waagen) [M] and Macrocephalites triangularis Spath [M] recorded from the lower "beds" of the Kuldhar Member ("bed" 4), facilitating the placement of the Bathonian-Callovian boundary between "beds" 4 and 5.

6 illus, 3 tables, 41 ref

021488   Hegde V S;Kanchanagouri Gosavi D (Civil Engineerin Dept, S D M College of Engineering and Technology, Dharwar-580 002, Email: vshegde2001@yahoo.com) : Plume related (?) acid volcanic activity in St. Mary's Island, South Kanara district, Karnataka. J Geol Soc India 2007, 70(1), 43-52.

: Metaluminous (Alumina Saturation Index A/CNK <1.04), acid volcanic rocks ranging in composition from rhyolite to dacite occur in St Mary's island. The rocks are rich in Si0₂ (68.58-71.27%), high field strength elements, moderately rich in Al₂O₃ (11.78-15.02%), and low in CaO, MgO, V, Cr, and Ni. They are characterized by fractionated light rare earth elements (La/Sm=6.8) and a flat heavy rare earth elements pattern with a large negative Eu anomaly (0.48). Variation in bulk- rock major and trace element composition together with mineral data on clinopyroxene composition, suggest a basaltic precursor and a cause related to rifting. The enrichments of incompatible elements point to an EM-I type mantle source. From the over all geochemical characteristics, it is inferred that the Marion plume caused the lower part of the basaltic crust to soften, stretch and rift in an extensional setting. The rise in the geotherm caused by the rising asthenosphere and the pressure change resulting from rifting lowered the solidus temperature and resulted in partial melting of the basaltic crust. Subsequent fractionation produced dacitic to rhyolitic magma, which was emplaced in a rift setting.

13 illus, 5 table, 47 ref

021487   Harbor D;Gunnell Y (Geology Dep, Washington and Lee University, Lexington, VA 24450, USA, Email: gunnell@paris7.jussieu.fr) : Along-strike escarpment heterogeneity of the western ghats: a synthesis of drainage and topography using digital morphometric tools. J Geol Soc India 2007, 70(3), 411-26.

Presents the first synthetic and systematic attempt to fingerprint topographic attributes of the Western Ghats passive margin escarpment using newly available SRTM digital elevation data. Spanning 12 degrees of latitude, the escarpment is shown to exhibit contiguous segments where scarp sinuosity and relief, but also drainage basin attributes such as stream orientation, spacing of scarp, coastline and continental divide, basin shape, basin hypsometry and stream longitudinal profile covary in ways that suggest differences in the process of retreat of the Western Ghats as a continuous yet heterogeneous landform. The methodology presented here could serve as an improvable template applicable to other escarpments around the world for comparative purposes. It can be potentially standardized as a tool designed to construct inferences about the variability of scarp retreat processes under a range of conditions tied to drainage and geological structure. For the Western Ghats, suggests that site-specific feedbacks between climate, drainage and geologic structure are key to understanding scarp dynamics and the manner in which the evolution of drainage boundaries across strike affect morphology and evolution along strike.

9 illus, 15 ref

021486   Gururajan N S;Choudhuri B K (NO, Wadia Institute of Himalayan Geology, Dehra Dun-248 001, Email: nsgura@wihg.res.in) : Geochemistry and tectonic implications of the trans-Himalayan Lohit Plutonic complex, eastern Arunachal Pradesh. J Geol Soc India 2007, 70(1), 17-33.

The Trans-Himalayan Lohit Plutonic Complex occurs to the east of the Eastern Syntaxis in eastern Arunachal Pradesh and the investigations were carried out mainly along the Lohit River section. The plutonic complex intrudes the metavolcanics of probable arc affinity in the west and high-grade metamorphic rocks of the Asian continental margin in the east. It can be sub divided into western and eastern belts, separated by Walong Thrust. The complex consists of multiple intrusions and they are: (1) an early phase of metaluminous, tholeitic to calc- alkaline gabbro and quartz diorites with minor diorites and hybrid rocks; (2) an intermediate phase of calc-alkaline, metaluminous, leucotonalite of high Al-trondhjemitic or adakitic composition; (3) a last phase of peraluminous leucogranite and associated veins of pegmatite and aplite. The enrichment of large-ion-lithophile elements (LILE) relative to high field strength elements (HFSE) of these rock types suggest that they were emplaced in a subduction related environment and derived from different source materials. The major and trace element variations in the early gabbro-quartz diorite, along with the low initial ⁸⁷S/⁸⁶Sr ratio (0.703-0.704) suggest that they were derived from a parental tholeitic magma, from which the intrusives have been differentiated under increasing water pressure conditions. The geochemical characteristics of the trondhjemites, such as the high Na₂0, Al₂O₃,Sr,Sr/Y ratios and lo w K₂O, Y and depletion of heavy rare earth elements (HREE) are similar to those of adakite and Archaean high Al-trondhjemite. Tehy might have been derived either by melting of the subducted oceanic crust or by partial melting of newly under-plated basaltic crust beneath the thickened continental arc leaving residual garnet and amphibole.

10 illus, 2 table, 47 ref

021485   Guru Rajesh K;Vara Prasad G S;Chetty T R K (NO, National Geophysical Research Institute, Hyderabad-500 007, Email: chettytrk@yahoo.co.in) : Structurally controlled drainage pattern in Precambrian mountainous terrain: a study from the southern Sahyadri, India. J Geol Soc India 2007, 70(3), 499-519.

Presents an analysis of relationship between the drainage pattern and structure of the bedrock in the southern Sahyadri that represents a part of the Precambrian Southern Granulite Terrain, India. Interpreted the lineaments from shaded relief maps prepared from the Shuttle Radar Topography Mission elevation data. The study area is divided into four blocks and the drainage pattern of each block is compared with the lineaments visually and statistically. Coincidence of the two datasets is quite strong implying a predominant control of structures on the drainage pattern. Drainage pattern is remarkably consistent with the Precambrian structural features like shear zones, metamorphic foliation, axial traces of folds and joints suggesting the dominant control exerted by the Precambrian structures on the present-day drainage. The drainage divide of the region broadly follows the lithological boundaries. Thus, it can be considered that the large-scale parameters of drainage viz. basin shape, size etc. are controlled by lithology while the orientation; pattern and length of individual streams are controlled by structural features of the underlying rocks.

11 illus, 5 tables, 35 ref

021484   Gurel A;Ciftci E;Erdal Kerey I (Dep of Geological Engineering, Nigde University, 51200 Nigde, Trukey) : Sedimentological characteristics of the cukurbag formation deposited along the ecemis fault zone, central Anatolia, Turkey. J Geol Soc India 2007, 70(1), 59-72.

The Oligocene C;ukurbag Formation, deposited within a long narrow basin surrounded by the Aladag, Ulukisla, and Nigde metamorphic Groups, consists of conglomerate, sandstone, siltstone, mudstone, marl, mudstone-gypsum successions. A number of analytical methods including morphological, mineralogical, and chemical techniques were employed to investigate the sedimentological characteristics of the formation. According to the grain size analyses, sediments of the formation are very poorly sorted with strong positive to near symmetrical skewness. The analyses show that irregular flow regime should have occurred during sedimentation of the C;ukurbag Formation. These sediments comprises mainly of quartz, feldspars, calcite, clinopyroxene, and Fe-oxides. Common clay minerals include smectite, chlorite, and kaolinite. The chemical analyses carried out on the samples representing the bottom to the top of the formation indicated that Si02, AI20), K20, and P20S contents are low compared to the world mudstone averages. However, MgO, CaO, and C contents contents are comparatively high. Four measured profiles showing the distribution of principle facies within the formation are prepared. Based on the profile analyses, seven distinct lithological facies were distinguished that include massive conglomerate,bedded conglomerate, stratified sandstone, cross-bedded sandstone, laminated siltstone, massive mudstone-marl, and laminated mudstone-gypsum. the study suggests that the sediments of thi formation must have been reworked material transported from unknown distances and deposited in an alluvial fan-braided stream and lacustrine environments.

6 illus, 3 table, 60 ref

021483   Gupta S K (Planning Commision, , Yojana Bhawan, New Delhi-110 001) : Wet & cool summer- dry, hot & humid monsoon in 2008 : an example of climate change. Green Fmg 2009, 2(5), 328-30.

Change of this year weather in North India is not a local but a worldwide phenomenon that leads to natural calamities such as cyclone, tsunami, earthquake, drought, excess rain, health hazards, depletion and degradation of bio and natural resources, etc. The glaciers are melting faster than anyone thought causing rising of sea level, vanishing of flora and fauna as welI losing water supply putting billions of people in lurch. Last winter, as the full scope of the global food crisis became clear, commodity prices doubled or tripled, provoking grumbling in America, riots in a few countries and the specter of greatly increased malnutrition. The UN is encouraging to start undoing a decades-long legacy of agricultural and trade policies that many blame for the failure of small farmers in poor countries to feed their own people.

11 ref

021482   Guha A K;Gopikrishna K (Dep of Geology and Geophysics, Indian Institute of Technology, Kharagpur-721 302, Email: gak3366@yahoo.co.in) : New calloporid (Bryozoa, cheilostomata) species from tertiary sequences of western Kachchh, Gujarat. J Geol Soc India 2007, 70(1), 121-30.

Eight cheilostomate bryozoan species (Aplousina sp., Copidozoum feddenin. sp., Crassimarginatella blanjordi n. sp., C. ukirensis n. sp., Marginaria senguptai n. sp., Planicellaria kharaiensis n. sp., P. naliyaensis n. sp. and Reptoporina chhasraensis n. sp. belonging to the family Calloporidae Norman, 1903 are described and illustrated for I the first time from the Tertiary (Lutetian to Aquitanian) sequences of western Kachchh, Gujarat. In the Tertiary bryozoan assemblages of this area, this family has the highest generic diversity.

3 illus, 1 table, 26 ref

021481   Goswami S (Dep of Environmental Sciences, Fakir Mohan University, Vyasa Vihar, Bangalore-756 019, Email: goswamishreerup@yahoo.com) : Palynological resolution of permian sequence in IB-river coalfield, Orissa and its environmental significance. J Geol Soc India 2007, 70(1), 131-42.

The Ib-River coalfield, a part of Mahanadi Master Basin has rich deposit of Lower Permian Barakar coal. The palynological analysis of sediments from this coalfield has revealed the presence of distinct palynoassemblages. These assemblages repre;ent Permian sequence from Lower Barakar (Early Permian) to Lower Kamthi (Late Permian) sediments. Palynological studies help in redefining the status of Barakar and Kamthi Formations and in classifying them. Here the palynological assessment has been compared with the megafossil work of the author. Based on the palaeobotanical data, the stratigraphy of this coalfield has been proposed and the environment during Permian time has been discussed in the paper.

4 illus, 48 ref

021480   Ghosh B;Mahoney J;Ray J (Geology Dep, University of Calcutta, 35, Ballygunge Circular Road, Kolkata-700 019, Email: bghosh_geol@hotmail.com) : Mayodia ophiolites of Arunachal Pradesh, northeastern Himalaya. J Geol Soc India 2007, 70(4), 595-604.

Ophiolite assemblage around Mayodia, Dibang Valley, Arunachal Pradesh falls in the eastern extension of the Indus suture belt and is represented by peridotite tectonite, hornblendite (dyke) and amphibolite. The entire succession is overlain by metabasalt carapace interlayered with metapelitic pelagic sedimentary rocks. The basal peridotite may be classified as wehrlite. The hornblendite typically occurs as intrusive within the peridotite tectonite and is represented by cumulus primary amphibole. The amphibolite is characterized by well developed gneissose banding. The pillow lava is represented by actinolite-chlorite-albite-epidote schist. The evolutionary trend of the ophiolite suite has been assessed based on major, trace and rare earth element data which favours partial melting of a depleted mantle source. Tectonic discrimination diagrams for the amphibolite and metabasalt clearly indicate their MORB affinity. Such ophiolite assemblage has developed as a result of collision of India and Asia that started with the closing of Tethyan ocean during Mesozoic and Early Tertiary.

8 illus, 4 tables, 32 ref

021479   Dinesh A C;Maran N;Nambiar A R;Unnikrishnan E;Jayaprakash C (Marine Wing, Geological Survey of India, Mangalore, Email: acdinesh@rediffmail.com) : Selective tsunami attacks along SW coast of India - how & why? and the role of tsunami warning system in the sub-continent. J Geol Soc India 2007, 70(4), 685-6.

^ssc

021478   Devaraju T C;Alapieti T T;Kaukonen R J; Sudhakara T L (NO, , Rajamangala, Saptapur, Haliyal Road, Dharwad-580 001, Email: devaraj63@sancharnet.in) : Petrological and PGE mineralisation study of the Channagiri mafic-ultramafic complex, Shimoga supracrustal belt, Karnataka. J Geol Soc India 2007, 70(4), 535-56.

Channagiri mafic-ultramafic complex constitutes the main lithounit of Hegdale Gudda Formation of the Shimoga Supracrustal Belt. Mapping at a scale of 1:2000 coupled with detailed petrological examination of the Platinum Group Element (PGE) mineralized 3.5 km x 0.3 km Hanumalapur segment of the complex has revealed that it is composed of outer gabbroic zone and central 100-150 m ultramafic zone. While V-Ti magnetite seams occupy the outer boundary of the ultramafic zone, several small isolated lenses/pods of anorthositic variation occur within the ultramafic zone itself. The complex is affected by penetrative deformation, hydrothermal alteration and low-grade metamorphism, which together have caused complete replacement of olivine and pyroxenes by chlorite, amphibole, epidote and carbonate. The gabbro forming outer zone is in the range of quartz gabbro-melagabbro and is strongly banded/foliated. The ultramafite in the central zone is a complex mix of the dominant fine (chromite-chlorite schist) and subordinate coarse grained units. The magnetite occupying the western interface zone is the typically coarse grained V-Ti variety whereas that on the eastern side includes narrow chromiferous lenses. PGE data obtained for the different units of Hanumalapur segment has revealed that only the central fine-grained ultramafite and the chromiferous lenses in the eastern magnetite seam host PGE mineralization of commercial interest with Pt+Pd values ranging from 1.5 to 6 ppm; the other lithologies of the segment as well as those constituting the remaining segments of Channagiri ultramafic complex and Hegdale Gudda Formation have not yielded positive anomalies of PGEmineralization. The governing control of chromite over the separation of PGE in the very early stages of magmatic crystallization is inferred taking into account the close association of PGE with the chromite-bearing units. The recorded textural relationships suggest that the PGEs remained virtually immobile during later penetrative alterations of the host rock.Geochemically, the PGE mineralized ultramafic units of Hanumalapur segment carry signatures of basaltic komatiite to Fe-rich tholeiite and in terms of Pd/Ir : Ni/Cu, Pd/Pt : Ni/Cu and Ni/Pd : Cu/Pt ratios they compare with layered intrusions. The chromite controlled PGE mineralization of Hanumalapura roughly resembles the UG2 of the Bushveld complex and a part of the SJ reef of the Penikat. Detailed logging of a 252 m deep drill core has revealed the existence of three ore reefs of 20, 30 and 35cm thickness, analyzing 3.7, 5.0 and 4.0 ppm Pt+Pd respectively, located within a 5 m zone, and 5 lower grade reefs of 0.35 m to 1.0 m thickness analyzing 1.3 to 1.8 ppm Pt+Pd (and 0.7 to 1.8% Cu), located in a 50 m wide zone, just above the main ore zone. The PGE reefs of Hanumalapur segment include both Pt- and Pd-rich ones but the latter dominate.

9 illus, 10 tables, 37 ref

021477   Dev S V;Radhakrishna M;Subrahmanyam C (Marine Geology and Geophysics Dep, School of Marine Sciences, Cochin University of Science and Technology, Fine Arts Avenue, Cochin-682 016, Email: mr_radhakrishna@hotmail.com) : Estimates of effective elastic thickness along the southwest continental margin of India using coherence analysis of gravity and bathymetry data - geodynamic implicationos. J Geol Soc India 2007, 70(3), 475-87.

In the study, Coherence analysis of gravity and bathymetry data of the region based on Maximum Entropy Spectral Estimation (MESE) method is used to understand the regional geodynamic processes and lithospheric strength that controls the flexure and basin evolution. The study brings out effective elastic thickness (Te) values of 5-10 km along the Konkan and Kerala basins, and the Comorin Ridge at the margin and 5-8 km along the Chagos Laccadive Ridge north of the equator. The elastic thickness values increase southward and maximum Te value of 10 km is observed below the Comorin Ridge. These results, combined with the earlier estimates of Te indicate low strength < 15 km for the lithosphere below the western margin, but not as low as that observed below plume affected margins. The observed low elastic strength at the margin will have implications on long term topographic evolution of the Western Ghats. The Marion Plume seems to have played limited role in the rifting and evolution process of the western margin. In the absence of such an active plume role, the substantial partial melt zone observed in the Comorin Ridge region based on geomagnetic induction models can be alternatively explained by invoking the convective partial melting model. The Comorin Ridge might have been emplaced as an oceanic basement high due to large-scale volcanism during the onset of seafloor spreading. Absence of diagnostic magnetic signature associated with the isostatic gradient over the Comorin Ridge that marks the Ocean Continent Boundary indicates that active volcanism due to strong convection might have blurred the crustal transition in the Comorin Ridge region.

4 illus, 84 ref

021476   Daneshian J;Sarkar S;Sharma V (Dep of Geology, teacher Training University, No-49, Mofatteh Ave, tehran, Iran, Email: jdaneshian@yahoo.co.uk) : Miocene palynoflora from Inglis island, Andaman sea and its palaeoecological implication. J Geol Soc India 2007, 70(1), 147-57.

A rich palynofloral assemblage has been recorded for the first time from a stratigraphic section of the Inglis Formation at Inglis Island, Andaman Sea, India. Forty-six genera and fifty-eight species belonging to different botanical groups viz., dinoflagellate cysts, fungal remains, pteridophytic spores, and gymnospermous and angiospermous pollen have been recognized. Geological ranges of some stratigraphically important palynotaxa suggest late Early Mioceneearly Middle Miocene age to the assemblage. The recorded palynofloral assemblage is also closely comparable to that recorded from late Early Miocene-Early Middle Miocene sediments of South India. The palynoflora has been compared with the modem equivalents and it indicates a warm humid climate with high degree of rainfall during the deposition of the sequence in the area of investigation.

6 illus, 1 table, 34 ref

021475   Bhattacharyya A;Shah S K;Chaudhary V (NO, Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow-226 007, Email: amalava@yahoo.com) : Feasibility of tree-ring data in palaeoseismic dating in northeast Himialaya. J Geol Soc India 2008, 71(3), 419-24.

Tree-rings are good proxy records for dating Palaeoseismic events. In a reconnaissance tree-ring analyses in the Northeast Himalayan region we find that several conifers of this region are suitable for the various aspect of dendroecological analysis. Discusses the feasibility of tree-ring width data of Abies densa growing at two distantly located sites of North-East Himalaya, Yumthang in Sikkim and T-Gompa in Arunachal Pradesh, towards dating Palaeoseismic events. Recorded that growths (ring-widths) are low either during the same year of known high intensity earthquakes of this region or subsequent year when it occurred during non-growing season of the tree. This implies that dated tree-ring sequences could be a promising tool in dating Palaeoseismic events of the Northeast Himalaya Since lower tree growth also noted in several non earthquake years, so for precision in application of tree ring in paleoseismic dating several tree-ring features other than ring width need to be considered along with proper selection of sites and trees preferably trees confine along the fault zones.

3 illus, 38 ref

021474   Basu H (NO, Atomic Minerals Directorate for Exploration and Research, Hyderabad-500 016, Email: basuhimadri@rediffmail.com) : Geological and geochemical aspects of the Gulcheru Formation in the southwestern margin of the Cuddapah Basin and its potentiality for uranium mineralisation. J Geol Soc India 2007, 70(4), 686-8.

^ssc1 table, 4 ref

021473   Basavaraju M H;Pundeer B S (KDMIPE, ONGC Ltd, , Dehra Dun-248 001, Email: basavamh_2002@yahoo.com) : Palynostratigraphy and source rock potential of subsurface gondwana sediments in Dhansiri valley, upper Assam. J Geol Soc India 2007, 70(1), 158-68.

The Gondwanas of Upper Assam are locally divided into Lower Gondwana and Upper Gondwana based the subsurface electro-logs, lithology and palynofossil assemblages. The Lower Gondwana is dominated by rich radial monosaccate genera viz. Plicatipollenites sp., Parasaccites sp., Potonieisporites sp., Virkkipollenites sp. along w trilete spores of Microbaculispora sp. and Microfoveolatispora sp and dated as Early Permian age. The palynoassemblages are closely comparable with those recorded from the Krishna-Godavari Basin, Cauvery Bas South Rewa Basin, Satpura Basin and Jayanthi coal fields which are considered as equivalents of Talchir Formation. The occurrence of Leiosphaeridia in the Early Permian sediments indicates a marine influence during the deposition of the sediments. The Early Cretaceous sediments of Upper Gondwana contains mainly of Tricolpites sp., Plicifera senonici Omamentifera sentosa, Cyclinospora reduncus, Staplinisporites sp., Cicatricosisporites sp., Classopollis sp., a Callialosporites sp. indicating an Aptian-Albian age. The equivalent palynoassemblages are reported from the Cauve and Krishna-Godavari Basins.

8 illus, 1 table, 15 ref

021472   Agarwal N;Sharma R;Basu S;Agarwal V K (Meterology and Oceanography Group, Space Applications Centre, Ahmedabad-380 015, Email: neeraj@sac.isro.gov.in) : Assimilation of sub-surface temperature profiles from agro floats in the Indian ocean in an ocean general circulation model. Curr Sci 2008, 95(4), 495-501.

Effects of assimilation of Argo temperature profile in an Ocean General Circulation Model (OGCM) are studied in the tropical Indian Ocean. Two assimilation experiments have been performed during the first five months of 2004. In the first one, monthly averaged Argo profiles have been assimilated using nudging tech- l nique and in the second, Cressman technique has been used for assimilating daily Argo profiles. The differ- ences in the isothermal layer depth (ILD), depth of the 20°C isotherm (D20) and sea surface temperature (SST) have been examined. The impact of assimilation has also been assessed using independent observations ] from one of the Indian Ocean Triton buoys. Errors in SST at the Triton buoy location are reduced by 37 and , 16% respectively, in the two experiments. ILD and D20 show significant improvement in terms of error reduction in both the experiments, implying improvement in the mixed layer and the thermocline region. The impact of assimilation using Cressman technique is more on ILD and D20 as is evident from the coeffi- ' cient of determination. This is because in the first experiment monthly averaged data have been assimi- lated leading to a comparatively poor representation of the high frequency variability of the parameters. Temperatures at the surface, 50 and 100 m depths during the forecast period (June-August 2004) have also been compared with Triton buoy observations.

5 illus, 12 ref

020633   Torabi G (Geology Dep, Isfahan Univ, Isfahan, Iran, Email: Torabighodrat@yahoo.com) : Neutron activation analysis of lamprophyric pillow lavas and plugs from central Iran. J Ultra Chem 2008, 4(1), 85-90.

Samples of lamprophyric pillow lavas and plugs from Central. Iran have been analyzed by NAA. The concentration of 28 elements, major and trace, are reported. Similar geochemical characteristics and parallel chondrite REE patterns of all samples, are remarkably thereby implying that they were all derived from a similar mantle source region and underwent similar melt extraction. These rocks are continental alkaline lamprophyres, that produced by low degree partial melting of upper mantle garnet lherzolites.

2 illus, 3 tables, 10 ref

020632   Sreedevi P;Ganesh Babu R;Ratnam M;Sreenivas C (A.P.Water Management Project, Network Centre, Undi-534 199) : Investigations for installation of drainage system to control salinity in Godavari Western delta. Andhra Agric J 2008, 55(3), 328-32.

Study on Pre drainage investigations carried out at Kalipatnam pilot area (18 ha) of Godavari Western Delta under Andhra Pradesh Water Management Project revealed that the pilot area is almost flat with a slope of 0.01 percent and a shallow water table of poor quality (EC 4.8 to 43.1 dS m^-1). The soils are highly saline with an EC 4.03 to 16.35 dSm^-1 and ESP 15 to 60%. The piezometer study concluded that there is vertical ground water movement in the pilot area and hence natural drainage is not possible. The Staff guage studies at Upputeru, revealed that there is back flow of sea water to the fields during summer. The tidal range of Upputeru varies from 0.0 to 0.9 m above MSL where as the maximum land elevation is 0.4 m MSL. Hence, pumped subsurface drainage system is recommended in the pilot area instead of gravity flow.

4 illus, 2 tables, 6 ref

020631   Nivanonee C;Manihar Sharma B (Life Sciences Dep, Manipur Univ, Canchipur-795 003) : Phytosociology of the macrophytes of ikop lake Manipur : quantitative analysis. Ecol Envir Conserv 2008, 14(4), 621-6.

Ikop Lake is a fresh water, saucer-shaped natural lake, situated in the South-Eastern part of Imphal at a distance of about 40 km. This eutrophic lake has an area of 13.5 sq. km and lies at an intersection of 93° 52' to 94°05' E longitude and 24°31 ' to 24°40' N latitude and it is situated at an altitude, of 772 m above the mean sea level. Phytosociological study was carried out for twentynine macrophytic species. Quantitative or objective analysis comprises Frequency, Density, Abundance, Abundance/ Frequency, ratio Relative Frequency, Relative Density, Relative Abundance and computation of Importance Value Index from the relative values of Frequency, Density and Abundance which gives the overall picture of ecological importance with respect to the community structure.

3 tables, 4 ref

020630   Niranjan Kumar K;Srinivas Varma K; Mallikarjuna Reddy R (Geology Dep, Kakatiya Univ, Warangal-Andhra Pradesh-506 009, Email: niranjankumarkollipara@yahoo.co.in) : Hydrochemistry and classification of groundwaters at Gajwel, Medak district, A.P., India. Ecol Envir Conserv 2008, 14(4), 571-8.

Hydrochemistry of the Gajwel, Medak district has been evaluated, as the evaluation of chemical quality of ground-water is an important aspect in its utilisation. A number of water samples have been analysed in details to classify and to understand the basic character of chemical composition of the groundwater and hydrochemical environment of the area. In order to understand the importance of quality of the groundwater and its suitability for a particular use both qualitative and quantitative studies have been carried out on the basis of chemical analysis to know the type of water and also composition and concentration of various constituents present in the water in order to establish whether the quality of groundwater of the area is suitable for different purposes. The quality fluctuations and the variations in the concentration of different ions have been identified. Thus, the analytical data has been correlated with different parameters like Wilcox diagram, U.S. Salinity Laboratory, Kelley's Index, SAR.TDS, RSC and Piper's Trilinear diagram etc. and have been used to classify the basic character of chemical composition of the groundwater. Based on the hydrochemistry, utilitarian aspects of groundwater's have been classified into three major divisions viz., i) domestic / drinking criteria, ii) irrigation / agricultural water criteria and iii) industrial water criteria.

3 illus, 4 tables, 36 ref

020629   Nabil;Al-Shwafi A (Earth and Environmental Science Dep, Faculty of Science, Sana'a Univ, Yemen) : N-alkane distribution in surficial sediments from the Aden city coast, Yemen. Nat Envir Pollut Technol 2008, 7(3), 429-33.

Presents the N-alkanes distribution in recent sediments of Aden city coast. The results are the first of their kind for the region and should serve as baseline for future studies. The concentration of N-alkanes in sediment samples ranged from 3to 1805 ng/g dry weight, expressed as Kuwait crude oil equivalent. It is evident that all the sites are contaminated to some extent with N-alkanes. N-alkanes generally constitute the major fraction of saturated hydrocarbons, and their distribution patterns are characterized by carbon-number ranges and predominance, depending on the nature of the source material and its microbial or geochemical alteration. In this respect it has been recognized that distributions exhibiting odd carbon-number predominance in the C₁₅-C₂₁ and C₂₅-C₃₁ ranges are characteristic of autochthonous and allochthonous natural inputs respectively, whereas slight even carbon-number predominance or smooth distribution in the C₂₀-C₃₀ range have been invoked for reduction or bacterial diagentic processes. Finally, fossil (petroleum) N-alkanes are characterized by a low carbon preference distribution generally concurrent with an unresolved complex mixture of branched and cyclic saturated hydrocarbons.

2 illus, 2 tables, 18 ref

020628   Gurugnanam B;Suganya M;Suresh M;Dharanirajan K (Institute for Ocean Management, Anna Univ, Chennai, Tamil Nadu) : Geochemical studies of groundwater present in upper Thirumanimuthar sub-basin, Tamil Nadu, India. Nat Envir Pollut Technol 2008, 7(3), 423-8.

Geochemical analysis of groundwater is employed to evaluate the postmonsoon 2005 water quality of upper Thirumanimuthar subbasin. Thirty two representative groundwater samples were collected from dug and bore wells. The samples were analysed to monitor the water chemistry of major ions. The results were evaluated in detailed and compared with WHO water quality standards. An overall assessment of the water samples indicated that all parameters are within the permissible limit except in some locations. According to the USSL diagram most of the samples falls in C₃ - S₁ class, which indicates its suitable nature. Piper trilinear diagram interpretations were made to know the chemical type of the groundwater. It reveals that the subsurface water is alkaline earth (Ca+Mg) exceeds alkalies (Na+K) type.

3 illus, 3 tables, 10 ref

020627   Gupta S K (Applied Geology Dep, Dr. Harisingh Gour Vishwavidyalaya, Sagar, Madhya Pradesh) : Conservation strategy for minerals: an appraisal for global energy crises and conservation of non-renewable energy resources and minerals for future generations. Ecol Envir Conserv 2008, 14(4), 691-7.

The natural mineral resources are not infinite and hence it is impossible to support an exponential increase in population on a finite resource base. The same is true for energy derived from mineral and fossil fuel resources.Very recently, the developed & developing countries have encountered the effects of energy shortages for the first time, including increase in the prices of energy and products produced from petroleum. Nearly 85 percent of the total energy consumed today is produced from coal, natural gas and petroleum, with small amounts of hydropower and, more recently nuclear power and other non-conventional sources. Some basic strategies for energy conservation and brief information about the consumption of various anergy sources by different industrials as well as by domestic sector is given with their conservation option. The basic strategy discussed in this paper can be applied to the entire spectrum of energy consuming sectors. The policy of conservation is founded on the concept that mineral resources are one-time indispensable assets. If these are not exploited now, these will neither grow in quantity nor perish, and will remain intact for the prosterity for ever.

1 illus, 17 ref

020626   Edokpayi;Aghatise C (Marine Sciences Dep, Faculty of Science, Lagos Univ, Yaba, Lagos, Nigeria) : Correlation and multiple regressions of the environmental conditions and its effect on the abundance of bottom dwelling Macrobrachium macrobrachion and Macrobrachium vollenhovenii in the brackish water zone of the Benin river, southern Nigeria. Ecol Envir Conserv 2008, 14(4), 777-87.

Pearson simple correlation of 12 physical and chemical characteristics from a 24 months investigation of five stations along a 5 km stretch of Benin River, southern Nigeria was evaluated. The effect of these environmental factors on the abundance of Maerobrachium macrobrachion and Macrobrachium vollenhovenii during this period was also discussed. There was variability in the number of significant correlations at each station in the two years. Also, no similarity among the stations in terms of interactions of factors was observed. Only the correlation of conductivity to pH and salinity and that of water level to transparency was found to be common to both years in each station. Conductivity, dissolved oxygen, calcium and nitrate-nitrogen were significantly (P < 0.05 - 0.001) influenced by the other environmental factors as reflected by the multiple regression analysis. The abundance of M macrobrachion and M vollenhovenii was significantly influenced by environmental conditions only in stations 1,11 and V. The interactions of the physical and chemical conditions and its influence on the abundance of M macrobrachion and M vol/enhovenii suggest that each station despite of their proximity may be unique and controlled by a set of local conditions.

12 tables, 27 ref

019647   Zamanian H;Patwardhan A M (Geology Dep, PO Box 465, Lorestan Univ, Khorram Abad, Iran, Email: zamanian138@yahoo.com ) : Skarn deposits related to the almoughlagh batholith, western Iran. J Geol Soc India 2007, 70(2), 252-64.

The Almoughlagh Batholith intruded during the Oligomiocene period the Triassic-Jurassic volcano-sedimentary sequence of the Songhor Series, occurring within the Sanandaz- Sirjan tectonic zone. The Baba All magnetite deposit is hosted by meta-dioritic rocks, the dioritic pluton intruded the Songhor Series earlier during the Late Kimmerian (~136 Ma) orogeny. The Chenar deposit is much smaller and is hosted by metamorphosed carbonate rocks interbedded with the Upper Songhor Series. The intrusion of Almoughlagh Batholith skarnized the meta-diorite and the impure carbonate units and the associated hydrothermal activity was accompanied by magnetite mineralization. The Baba Ali deposit has been identified as a calcic Fe-skarn, while the Chenar deposit has characteristics of calcium-magnesium skarn. The batholith consists of rocks belonging chiefly to the quartz-syenite and syenogranite groups, which are low in modal quartz, metaluminous to peraluminous and calc-alkaline in composition. A descending temperature regime, beginning at the peak of thermal metamorphism (566°C) and ending with the main phase of magnetite mineralization (450-350°C) has been deduced.

14 illus, 5 tables, 42 ref

019646   Yang X Y;Huang J;Wang K R (CAS Key Laboratory of Crust-Mantle Materials and Environments, School, University Science and Technology of China, Hefei 230026, China, Email: xyyang@ustc.edu.cn) : Trace element geochemistry of some mesozoic yanshanian copper-gold deposits on Anhui middle-lower yangtze metallogenic valley, Central-east China. J Geol Soc India 2007, 70(2), 235-51.

Yangtze valley is one of the most important metallogenic regions in the Jurassic-Cretaceous period in East Asian continent, where more than 200 polymetallic Cu-Fe-Au and Mo, Zn, Pb, Ag deposits are documented. Cu-Au deposits in Anhui Province (Lower part of Yangtze) are the most important among these deposits. Data of chemical compositions of trace elements were collected from literature for Yanshanian (Mesozoic) igneous rocks which have close relationship with the Cu-Au mineralization. The Cu -Au mineralization in middle to lower Yangtze valley can be divided into three types: mainly skarn type, porphyry type and volcanic type. In this paper, the details of trace and rare earth elements from Shaxi, Anqing, Chuxian, Tongling and Luzong Cu-Au bearing deposits are dealt with in detail. Rocks in the localities of Shaxi, Chuxian and Anqing intrusives have almost similar REE distribution patterns which show little assimilation with the wall rocks during the formation of Cu-Au deposits. However, the REE distribution patterns in Tongling skarn deposit are different altogether when compared to the other Cu-Au related rocks adjacent to areas of Mesozoic intrusives. This might have resulted due mainly to the volatile transport or assimilation of some elements producing complex patterns of trace element distributions superimposed on effects caused by crystal/melt equilibria. The trace element distribution shows that the mantle compatible elements such as Sc, Cr, Co and Ni and some transitional compatible elements such as Ti, V, Mn, Fe and Cu have strongly fractionated compared to the average contents of trace elements of crustal rocks, especially those of Cu, with very largely positive anomaly. This could be interpreted as an important crustal-mantle interaction during the Yanshania (Mesozoic) period when the multiple Cu-Au mineralization formed in the Yangtze metallogenic belt in China. The lithophile elements such as K, Rb, Th, Sr, Ba, Li and La are also enriched compared to the average contents of the crustal rocks, reflecting the regional geochemical anomalies of these elements and may be interpreted as an important reason of Cu-Au mineralization in this region.

8 illus, 3 tables, 24 ref

019645   Wu Z;Zhot H;Peng X;Jia N;Wang Y;Yuan L (State Key Laboratory of Marine Geology, Tongji University, Shanghai-200 092, China, Email: wuzj@tongji.edu.cn) : Anaerobic oxidation of methane in coastal sediment from Guishan Island (Pearl river Estuary), South China sea. J Earth Syst Sci 2008, 117(6), 935-43.

The concentrations of CH₄, SO^2-₄, ∑CO₂ and the carbon isotope compositions of ∑CO₂ and CH₄ in the pore-water of the GS sedimentary core collected from Guishan Island (Pearl River Estuary), South China Sea, were determined. The methane concentration in the pore-water shows dramatic changes and sulfate concentration gradients are linear at the base of the sulfate reduction zone for the station. The carhon isotope of methane becomes heavier at the sulfate-methane transition (SMT) likely because of the Raleigh distillation effect; ¹²CH₄, was oxidized faster than ¹³CH₄ and this caused the enrichment of residual methane δl3C and δ13C-∑CO₂ minimum. The geochemical profiles of the pore-water support the existence of anaerobic oxidation of methane (AOM), which is mainly controlled by the quality and quantity of the sedimentary organic matter. As inferred from the index of δ¹³C- TOC value and TOC /TN ratio, the organic matter is a mix of mainly refractory terrestrial component plus some labile alga marine-derived in the study area. A large amount of labile organic matter (mainly labile alga marine-derived) is consumed via the process of sedimentary organic matter diagenesis and this reduces the amount of labile organic matter incorporated into the base of the sulfate reduction zone. Due to the scarcity of labile organic matter, the sulfate will in turn be consumed by its reaction with methane and therefore AOM takes place. Based on a diffussion model, the portion of pore-water sulfate reduction via AOM is 58.6%, and the percentage of ∑CO₂ in the pore-water derived from AOM is 41.4%. Thus, AOM plays an important role in the carbon and sulfur cycling in the marine sediments of Pearl River Estuary.

4 illus, 39 ref