019644   Urrutia-Fucugauchi J;Perez-Cruz L (Laboratorio de Paleomagnetismo y Paleoambientes, Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Ciuda, Circuito Exterior S/N, Coyoacan, DF 04510, Mexico, Email: juf@geofisica.unam.mx) : Post-impact carbonate depostion in the Chicxulub impact crater region, Yucatan platform, Mexico. Curr Sci 2008, 95(2), 248-52.

The Chicxulub crater has attracted considerable attention as one of the largest terrestrial impact structures and its association with the Cretaceous/Palaeogene boundary. Analyses of stable isotopes and magnetostratigraphic results for the Paleocene carbonate sequence in the Santa Elena borehole are used to investigate the post-impact sequence and estimate the age of basal sediments in the southern crater sector. Studies of impact ejecta and cover sediments and modelling of post-impact processes suggest erosion effects due to sea-water back surge, block slumping and partial rim collapse of post-impact crater modification. Correlation of stable isotope patterns with the global pattern for marine carbonate sediments provides a stratigraphic framework for the basal Paleocene carbonates. Magnetic polarity constrains correlation of stable isotope variations with the reference Cenozoic isotopic data suggest that the first 17 m above the breccia-carbonate contact represents about 2.5 Ma. The stable isotope data suggest a gap of less than 0.1 Ma, whereas the magnetic polarity data (absence of reverse-polarity samples above impact breccia contact) suggest a gap up to 0.25 Ma.

6 illus, 27 ref

019643   Trilochan Singh (Wadia Institute of Himalayan Geology, North East Unit, Itanagar-791 113, Email: tskaith@rediffmail.com) : Geology of Itanagar capital complex, Arunachal himalaya, with special reference to neotectonics. J Geol Soc India 2007, 70(2), 339-52.

The geology of Itanagar Capital Complex of Arunachal Pradesh is least known. It constitutes mainly Siwalik sediments and unconsolidated Quaternary deposits. The Siwalik sediments are represented by Dafla, Subansiri and Kimin Formations belonging to the Middle Siwalik. The Quaternary sediments have been classified into four formations, viz., Itanagar Formation, Banderdewa Formation, Sonajuli Formation and Pachin Formation. Structurally, the area is squeezed between the Himalayan Frontal Fault in the south and the Bomdila Thrust in the north, and is traversed by a number of other local thrusts and active faults. Morphological features indicating neotectonic activity suggest that the area is geodynamically active.

7 illus, 1 table, 30 ref

019642   Talib A;Gaur K N (Geology Dep, Aligarh Muslim Univ, Aligarh-202 002, Email: talib04@rediffmail.com) : Foraminiferal composition and age of the chari formation, Jumara dome, Kutch. Curr Sci 2008, 95(3), 367-73.

The Chari Formation exposed at Jumara Dome, western Kutch yielded a prolific foraminiferal assemblage comprising 51 species, including one new species. Sixteen species are reported for the first time from the Indian region. The foraminiferal assemblage, dominated by families Vaginulinidae and Nodosariidae, is employed to date these sediments. The assemblage includes mostly long-ranging species. However, on the basis of a few short-ranging species restricted within the Callovian-Oxfordian and some species though long-ranging but mostly occurring in the Callovian-Oxfrodian sequences of different parts of the world, a Callovian to Ox-fordian age is assigned to the studied sequence. A Callovian age is favoured as the lower limit of the Chari Formation of the Kutch Jurassic on the basis of some representative Callovian foraminiferal species occurring in the lowermost lithounit of the Chari Formation in the Jumara Dome. An attempt is made to delineate the Callovian-Oxfordian boundary in the studied sequence on the basis of some fairly restricted and characteristic Callovian and Oxfordian foraminiferal species.

5 illus, 64 ref

019641   Sunder Raju P V (NO, National Geophysical Research Instiute, Hyderabad-506 606, Email: pvsraju@ngri.res.in) : Role of pathfinder elements in gold exploration in chitradurga schist belt. Curr Sci 2008, 95(3), 323-5.

^ssc2 illus, 1 table, 11 ref

019640   Sujatha C H;Aneeshkumar N;Renjith K R (Chemical Oceanography Dep, Coshin Univ of Science and Technology, Cochin-682 016, Email: ch_suji@yahoo.com) : Chemical assessment of sediment along the coastal belt of Nagapattinam, Tamil Nadu, India, after the 2004 Tsunami. Curr Sci 2008, 95(3), 382-5.

Concentration levels of Cr, Ni, Zn, Pb and Cu in relation to those of the nutrients - total phosphates, exchangeable nitrates, total organic carbon, etc. have been investigated in the sediments of Nagapattinam beach after the 2004 tsunami. The maximum values in the study area were 3204, 75, 71, 57 and 18.5 μg g^-1 for Cr, Ni, Zn, Pb and Cu respectively; Cd was below detectable level. AH the trace elements were relatively high in the near-shore sediments and the distribution pattern of the metals in the study area was in the order: Cr > Ni > Zn > Pb > Cu. The study shows that the tsunami has brought the clayey sediments from the sea-bottom that were settled for years together in inland areas as well as from the offshore sediments. The event has changed the chemical composition of the beach sediments and is threatening fishing grounds even in trace concentrations.

5 illus, 1 table, 22 ref

019639   Srivastava P K;Gupta Y P;Qazi M A (Geology Dep, Jammu Univ, Jammu-180 006, Email: srivastav_pk@rediffmail.com) : Geochemistry of rare metal bearing a-type dhanota granite, Mahendragarh district, Haryana. J Geol Soc India 2007, 70(2), 265-72.

The Protcrozoic Dhanota granite has intruded the Delhi Supergroup in the North Delhi Fold Belt (NDFB). Geochemically, it is a silica-rich, weakly paraluminous, sodic granite, enriched in high field strength elements (Zr, Nb, Y, Th) and Ga, with higher Ga/Al, Th/U and lower Ba/Rb ratios. The mineralogical and geochemical characters indicate the Dhanota granite as A-type, emplaced in an extensional/non-compressive tectonic regime around 665° C at pressure of 5 kb. The anorogenic nature of the Dhanota granite distinguishes it from the other syn-orogenic, S-type granitoid bodies emplaced in the NDFB. Uranium-thorium-REE mineralization as uranothorite and xenotime is recorded in the Dhanota granite. This, together with its occurrence in proximity to the U-mineralized albitite line, and enrichment of HFS elements necessitate exploration for radioactive, rare metal and rare earth minerals in the area.

8 illus, 3 tables, 24 ref

019638   Srinivasa Vittala S;Govindaiah S;Honne Gowda H (Central Ground Water Board, Mid-Eastern Region, Ministry of Water Resources, Patna-800 001, Email: vittala_99@rediffmail.com) : Prioritization of sub-watersheds for sustainable development and management of natural resources: an integrated approach using remote sensing, GIS and socio-economic data. Curr Sci 2008, 95(3), 345-54.

The study area is one the watershe of North Pennar basin, covering an area of 570 km² and lies between latitude 13°55'-14°17'N and longitude 77°05'-77°25'E in Pavagada area, Tumkur District, Karnataka and a small portion in Ananthpur District, Andhra Pradesh, India, forming a part of the hardrock terrain. The drainage network shows dendritic to sub-dendritic pattern and is non-perennial in nature. Poor soil cover, sparse vegetation, erratic rainfall and lack of soil moisture characterize the area for most part of the year. Recurring drought coupled with increase in ground-water exploitation results in decline the groundwater level. The entire study area has been further divided into nine sub-watersheds, namely Byadanur, Devada-betta, Talamaradahalli, Gowdatimmanahalli, Naliga-nahalli, Nagalamadike, Maddalenahalli, Paluvalli tank and Dalavayihalli, ranging in geographical area from 49 to 75 km. It has been taken up for prioritization based on available natural resources derived from satellite images and socio-economic conditions, including drainage density, slope, water yield capacity, ground-water prospects, soil, wasteland, irrigated area, forest cover and data on agricultural labourers, SC/ST population and rainfall. On the basis of priority and weightage assigned to each thematic map, the sub-watersheds have been grouped into three categories: high, medium and low priority. The prioritization results reveal that Nagalamadike, Maddalenahalli and Dalavayihalli sub-watersheds rank highest on the basis of weightage and are considered as high priority. These sub-watersheds may be taken up with development and management plans to conserve natural resources on sustainable basis with immediate effect, whjch will ultimately lead to soil and water conservation.

10 illus, 4 tables, 24 ref

019637   Somaru Ram;Borgaonkar H P;Sikder A B (NO, Indian Institute of Tropical Meteorology, Pune-411 008, Email: somaru@tropmet.res.in) : Tree-ring analysis of teak (Tectona grandis L.F.) in central India and its relationship with rainfall and moisture index. J Earth Syst Sci 2008, 117(5), 637-45.

Tree-ring-width index chronologies of teak (Tectona grandis L.F.) from three sites in central India have been studied for their dendroclimatic potential. The existence of good correlation among the three site chronologies indicates the influence of common forcing factor to the tree growth of the region. Tree growth and climate relationship based on correlation analysis revealed the important contribution of moisture index and rainfall rather than the direct influence of the temperature on tree growth during different seasons. Significant positive relationship of moisture index and rainfall during the monsoon months as well as on the annual scale with tree-ring width variations over the region indicates the important role of moisture availability at the root zone. The results suggest that the teak tree-ring chronologies can be used as high resolution proxy for past precipitation and moisture level in the environment.

6 illus, 2 tables, 25 ref

019636   Som S K;Bandyopadhyay K C;Prasad R K (Earthquake Geology Div, Eastern Region, DK-Block, Sector-II, Salt lake City, Kolkata-700 091, Email: sksom@rediffmail.com) : Cesium enrichment and resource evaluation in aplite and pegmatite at the southern slope of Belamu hill, Purulia district, West Bengal. J Geol Soc India 2007, 70(2), 273-81.

The cesium bearing aplite and pegmatite in the southern slope of Belamu hill occur in association with calc-silicate and granite gneiss country rocks of Chhotanagpur Gneissic Complex (CGC). The hydrothermal units are highly peraluminous and tectonically disturbed in which, cesium is mainly incorporated within pollucite and Li- muscovite. Rb/Sr shows sympathetic relationship with cesium having a strong correlation towards the higher end for both aplite and pegmatite. Cesium resource evaluation by ground survey and shallow drilling has been done for aplite and pegmatite. Reserves and grades established for both aplite and pegmatite have shown concordance with the statistical laws of distribution, suggestive of productive output.

16 illus, 3 tables, 19 ref

019635   Singh M K;Mahato N K;Singh P (Applied Mathematics Dep, Indian School of Mines University, Dhanbad-826 004, Email: drmka20@rediffmail.com) : Longitudinal dispersion with time-dependent source concentration in semi-infinite aquifer. J Earth Syst Sci 2008, 117(6), 945-9.

An analytical solution is obtained to predict the contaminant concentration along unsteady groundwater flow in semi-infinite aquifer. Initially, the aquifer is not supposed to be solute free, i.e., aquifer is not clean. A time-dependent source concentration is considered at the origin of the aquifer and at the other end of the aquifer, it is supposed to be zero. The time-dependent forms of unsteady velocities are considered in which one such form, i.e., sinusoidal form represents the seasonal pattern in a year in tropical regions. The Laplace Transformation Technique (LTT) is used to get an analytical solution and a graphical representation is made trough MATLAB.

2 illus, 13 ref

019634   Singh K K;Patel R P;Singh J;Kumar B;Singh A K;Singh R P;Koul B L;Lalmani (Atmospheric Research Laborutory, Physics Dep, Banarus Hindu University, Varanasi, Email: rppatel12@yahoo.co.in) : Observations of unusual whistlers during daytime at Jammu. J Earth Syst Sci 2008, 117(3), 219-25.

Reports observations of unusual whistlers recorded at Jammu (geomag. lat. = 22°26'N; L = 1.17), India on March 8, 1999 during the daytime. They are interpreted as one-hop ducted whistlers having propagated along higher L-values in closely spaced narrow ducts from the opposite hemispheres. After leakage from the duct, the waves might have propagated in the earthªionosphere waveguide towards the equator in surface mode. Tentative explanation of the dynamic spectra of these events is briefly presented.

4 illus, 29 ref

019633   Singh D;Ganju A (Research and Development Centre, Snow and Avalanche Study Establishmen, , Chandigarh-160 036, Email: dan_@rediffmail.com) : Mountain range specific analog weather forecast model for northwest Himalaya in India. J Earth Syst Sci 2008, 117(5), 575-87.

Mountain range specific analog weather forecast model is developed utilizing surface weather observations of reference stations in each mountain range in northwest Himalaya (NW-Himalaya). The model searches past similar cases from historical dataset of reference observatory in each mountain range based on current situation. The searched past similar cases of each mountain range are used to draw weather forecast for that mountain range in operational weather forecasting mode, three days in advance. The developed analog weather forecast model is tested with the independent dataset of more than 717 days (542 days for Pir Panjal range in HP) of the past 4 winters (2003-2004 to 2006-2007). Independent test results are reasonably good and suggest that there is some possibility of forecasting weather in operational weather forecasting mode employing analog method over different mountain ranges in NW-Himalaya. Significant difference in overall accuracy of the model is found for prediction of snow day and no-snow day over different mountain ranges, when weather is predicted under snow day and no-snow day weather forecast categories respectively. In the same mountain range, significant difference is also found in overall accuracy of the model for prediction of snow day and no-snow day for different areas. This can be attributed to their geographical position and topographical differences. The analog weather forecast model performs better than persistence and climatological forecast for day-l predictions for all the mountain ranges except Karakoram range in NW-Himalaya. The developed analog weather forecast model may help as a guidance tool for forecasting weather in operational weather forecasting mode in different mountain ranges in NW - Himalaya.

4 illus, 6 tables, 11 ref

019632   Simpson M;Raman S;Suresh R;Mohanty U C (Marine Dep, Earth and Atmospheric Sciences, North Carolina State University, Rakeuggm BC 27695-8208, USA, Email: msimpson@llnl.gov) : Urban effects of Chennai on sea breeze induced convection and precipitation. J Earth Syst Sci 2008, 117(6), 897-909.

Doppler radar derived wind speed and direction profiles showed a well developed sea breeze circulation over the Chennai, India region on 28 June, 2003. Rainfall totals in excess of 100 mm resulted from convection along the sea breeze front. Inland propagation of the sea breeze front was observed in radar reflectivity imagery. High-resolution MM5 simulations were used to investigate the influence of Chennai urban land use on sea breeze initiated convection and precipitation. A comparison of observed and simulated 10 m wind speed and direction over Chennai showed that the model was able to simulate the timing and strength of the sea breeze. Urban effects are shown to increase the near surface air temperature over Chennai by 3.0 K during the early morning hours. The larger surface temperature gradient along the coast due to urban effects increased onshore flow by 4.0 m S^-1. Model sensitivity study revealed that precipitation totals were enhanced by 25 mm over a large region 150 km west of Chennai due to urban effects. Deficiency in model physics related to night-time forecasts are addressed.

15 illus, 27 ref

019631   Sharma N;Khare N;Pandey P C;Vyas N K;Bhandari S M (National Centre for Antarctic & Ocean Reserch, , Goa) : Sea ice characteristics in arctic circle. Bull envir Sci 2006, 24(1), 19-24.

The Arctic Circle is commonly associated with the 66th parallel - a geographic ring crowning the globe. A broader definition includes the Arctic and Subarctic regions of Alaska, Canada, Greenland, Iceland, Scandinavia, Siberia and the Russian Far East. Space-borne infrared and passive microwave sensors are ideal platforms for monitoring spatially distributed polar ice properties and climate variables on short temporal scales. If properly utilized these sensors have the potential to provide over two decades of valuable temperature and snow property datasets for expansive areas. Microwave emission is conventionally related to physical temperature via "effective emissivity", a ratio of time-averaged brightness temperature (T8) and physical (usually, surface temperatures. The difference between the known T8 measured by the SMMR, SSM/I and MSMR sensors and simulated T8, based on surface temperature measurements Variation in the extents of sea ice cover at the Arctic Circle and the areas of the open water enclosed within them is observed on monthly bases during the interval of 1987ª2000 by SSM/I and 1999-2001 by MSMR. The global average temperature is increasing. During these years there are significant decreases in the Ice extent and open water areas within the ice cover in the Arctic Circle due to increasing temperature.

3 illus, 1 table, 13 ref

019630   Sen Jaiswal R;Uma S;Santhakumaran A (Physics Dep, Sona College of Technology, Salem-636 005, Email: senoritta_in@yahoo.co.in) : Z-R relationship over Gadanki for different rainfall rates. Indian J Radio Space Phys 2009, 38(3), 159-64.

Z-R relationship for different rain fall rates over Gadanki has been studied over a period of four years 1998-2001. The basic data set consists of rainfall rates and reflectivities derived from disdrometer during this period. The study has been carried out for rainfall rates R≤ 0.5 mmh^-1, 0.5<R≤ 4.0 mmh^-1, 4<R≤10 mmh^-1, 10<R≤ 50 mmh^-1 and R>50 mmh^-1. Shows that Z-R relationship varies for different rainfall rates. The various functional relations between reflectivity and rainfall rate are obtained.

019629   Ray D;Mirza I H;Surya Prakash L;Kaisary S; Sarma Y V B;Rao B R;Somayajulu Y K;Drolia R K;Kamesh Raju K A (NO, National Institute of Oceanography, Goa-403 004, Email: sujata@nio.org) : Water-column geochemical anomalies associated with the remnants of a mega plume: a case study after CR-2003 hydrothermal event in carlsberg ridge, NW Indian ocean. Curr Sci 2008, 95(3), 355-60.

An unusually large hydrothermal event (CR-2003) was reported over the slow-spreading Carlsberg Ridge between 05°41'N, 61°30'E and 06°20'N, 60°33'E. To investigate the after effects (if any) of such a large-scale emission, almost a year later in July 2004, the water column along the 50 km ridge segment was surveyed. Results show that while the thermal and optical signatures have largely reduced with time, the chemical signatures do persist between 2500 and 2900 m. Geochemical features like Fe/Mn, Mn/heat ratios, characteristic of event plume, also show major changes. Distribution of dissolved manganese, methane, helium-3 and suspended particulates further down the water column was indicative of one more plume layer between 3150 and 3400 m. The high volatile and less particulate metal content of the deep layer points towards a relatively fresh event.

3 illus, 1 table, 25 ref

019628   Rasheed M A;Veena Prasanna M;Satish Kumar T; Patil D J;Dayal A M (NO, National Geophysical Research Institute, Uppal Road, Hyderabad-500 606, Email: dayaisotope@yahoo.com) : Geo-microbial prospecting method for hydrocarbon exploration in Vengannapalli village, Cuddapah basin, India. Curr Sci 2008, 95(3), 361-6.

Reports high bacterial counts for methane (5.4 * 10⁵ cfu/g), ethane (5.5 x 10⁵ cfu/g) and propane-oxidizing bacteria (4.6 x 10⁴ cfu/g) in soil samples collected from Vengannapalli Village. The adsorbed light gaseous hydrocarbon analyses show the presence of moderate to low concentrations of methane (12.4-222.8 ppb), ethane (3-35.9 ppb), propane (2-24.3 ppb) and butane (1-18.4 ppb) in the soil samples. Carbon isotope analyses of few soil samples show enriched δ^{13C1 values of methane ranging from -35.0 to -10.6%, indicative of methane oxidation. Geo-microbial prospecting method coupled with adsorbed soil gas and carbon isotope studies, suggest that hydrocarbon micro-seepage of subsurface origin is present in the area and indicate that the area is worth visiting for conventional petroleum exploration.}

8 illus, 2 tables, 37 ref

019627   Radhakrishna T;Krisnendu N R;Balasubramonian G (NO, Centre for Earth Science Studies, Trivandrum-695 031, Email: tradha1@rediffmail.com) : Mafic dyke magmatism around the Cuddapah basin: age constraints, petrological characteristics and geochemical inference for a possible magma chamber on the southwestern margin of the basin. J Geol Soc India 2007, 70(2), 194-206.

Profuse Proterozoic basic magmatism is represented by mafic dykes all around the Cuddapah Basin and by lava flows/sills at different stratigraphic levels of sedimentary sequences within the basin. However, the genetic links between magmatism all around and within the basin are rather obscure. Available geochronological data have been examined in the light of our geochemical and palaeomagnetic results. The geochemical results clearly show that the dykes are sub-alkalic tholeiitic basalts in composition and no distinctions are visible in the elemental trends with respect to field orientations or discrete age groups. However, the LIL. element chemistry has been variably affected by different degrees of alteration. Such an alteration seems to have resulted in wide range in their ages, mainly by the Rb-Sr, K-Ar and Ar-Ar methods. Using palaeomagnetic constraints we recalculated the Sm-Nd isotopic data of three dykes of Mahabubnagar-Wanparti sector and estimated c. 2.4 Ga and 2.1 Ga age for the early dyke magmatism around the Cuddapah basin. Two other discrete dyke magmatic activities are assigned 1.8 and 1.65 Ga based on palaeomagnetic correlations. Thus, the sub-alkalic tholeiitic basic magmatism within lower Cuddapah Basin and around is confined to the Palaeoproterozoic times and the younger ages are attributed to disturbed isotopic systems. An interesting observation is that the dykes in the Anantapur-Gooty sector are predominantly rich in MgO, Ni and Cr and low in Zr and are dominated by olivine cumulus mineralogy. This feature evidently suggests that the dykes in this region solidified in much closer proximity to the subsurface magma chamber, retaining early-formed dense phases like olivine still as cumulates/phenocrysts. Such an interpretation provides geochemical support to the inference from Bouguer gravity anomaly for subsurface magma underplating in the southwest Cuddapah Basin. This is the first study from India to provide support from the geochemistry of dykes for subsurface magmatic body inferred from gravity anomaly.

9 illus, 1 table, 22 ref

019626   Preshanth M;Narender Reddy K (Geology Dep, Kakatiya University, Warangal-506 009) : Fluoride in groundwaters of Warangal district, Andhra Pradesh. Bull envir Sci 2006, 24(1), 25-31.

Fluorosis is an intense natural problem faced by many people of Warangal District in Andhra Pradesh. Keeping in view, an attempt is made to study the reasons for fluoride occurrence in the groundwaters of the district. The area is covered by three major litho-units such as Archaeans, Proterozoics and Gondwanas successively. Based on the analysed groundwater samples data collected from different parts of the district and in relation to the geology, the area is divided into three zones - high, medium and low fluoride areas. The western part of the area covered by Archaeans is more affected by this crippling disease than the eastern part of the district represented by sedimentaries.

2 illus, 2 tables, 8 ref

019625   Prasannakumar V;Lloyd G E (School of Earth Sciences, Leeds Univ, Leeds LS2 9JT, UK, Email: vprasan56@gmail.com) : Development of crystallographic lattice preferred orientation and seismic properties in Bhavani shear zone, Southern India. J Geol Soc India 2007, 70(2), 282-92.

Shear markers and shear sense indicators from the Bhavani shear zone (BSZ), a member of the south Indian Proterozoic shear system, separating the northern Archaean and southern Pan African granulite terranes, suggest multiphase reactivation. There is a progressive increase in mylonitisation corresponding to a progression in strain. The LS fabrics indicate near vertical principal flattening plane trending ENE-WSW, but with subvertical as well as subhorizontal stretching lineations implying a possible reactivation history with opposing movement vectors. Whilst the SEM-EBSD derived LPO of amphibole, biotite and feldspars suggest plastic deformation through the activation of intracrystalline slip systems, diffusiona! creep accommodated deformation can be inferred from the quartz LPO. All LPO suggest modifications in the fabric due to both retrograde and prograde reactivation during the tectono-thermal history of the BSZ over a period of nearly 2.0Ga. Petrofabric-deri ved seismic properties for the BSZ suggest that it exhibits a considerable seismic anisotropy, which reflects the petrofabrics of hornblende and biotite. Both LPO and seismic property observations imply conflicting tectonic X and Y directions, indicating possible superposition of contrasting X and Y vectors during different phases of the shear zone reactivation.

7 illus, 1 table, 62 ref

019624   Patel S C;Sundararaman S;Dey R;Thakur S S; Kumar M (Earth Sciences Dep, Indian of Technology, Powai, Mumbai-400 076, Email: scpatel@iitb.ac.in) : Deformation pattern in a proterozoic low pressure metamorphic belt near Ramanujganj, western Chhotanagpur terrane. J Geol Soc India 2007, 70(2), 207-16.

The Ramanujganj area in eastern India exposes a Proterozoic metasedimentary belt (~35 km x 18 km) which has been mapped in detail in terms of two pelitic and two psammitic lithounits. Dominant rock types in the belt include porphyroblastic argillite, phyllite and pelitic schist, feldspathic quartzite and orthoquartzite. The belt has an elongated oval shape with broadly NW-SE trend. Folds of three generations (F₁, F₂ and F₃) have been recorded. F, folds are rarely preserved as small isoclinal folds on bedding (S₀) associated with an axial planar cleavage (S₁). F₂ folds involve transposed S₀ + S₁ surfaces and vary from open to isoclinal, with steeply inclined axial plane and moderate plunge. Several large scale F₂ closures with NW to NNW striking axial planes are exposed. F₃ folds are steeply inclined to upright in nature with NE striking axial planes. Large scale F₃ folds are usually broad warps. Interference patterns of dome and basin type and hook type are observed in the area. F₁ and F₂ folds are broadly coaxial in nature, and their superposition has resulted in hook shaped pattern. F₂ and F₃ folds have superposed to produce dome-and-basin structures on both outcrop scale and large scale. The regional structure of the area is an elongate basin resulting mainly from the interference of F₃ folds on F₂ structures. The western and northern parts of the area are occupied by biotite quartzofeldspathic orthogneiss which intruded during or before F₁ deformation. In the eastern part mesocratic granodiorite intruded after F₁ deformation and before or during F₂ deformation. The Ramanujganj pelites are commonly characterised by large porphyroblasts of andalusite (chiastolite), whereas biotite and garnet form relatively small porphyroblasts. Andalusite occurs in the southeastern and central parts of the area, and transforms to sillimanite as we go towards northwest. This indicates increasing grade of metamorphism from southeast towards northwest. The metamorphism is of low pressure type.

5 illus, 1 table, 20 ref

019623   Pandit M K;Wall H D;Chauhan N K (Geology Dep, University of Rajasthan, Jaipur-302-004, Email: mpandit_jp1@sancharnet.in) : Paleosol at the Archean-Proterozoic contact in NW India revisited: evidence for oxidizing conditions during paleo-weathering. J Earth Syst Sci 2008, 117(3), 201-9.

A number of fine-grained sericite bearing pelitic, schistose lithologies occur along the Archean (Banded Gneiss Complex)-Proterozoic (Aravalli Supergroup) contact (APC) in the Udaipur valley in NW Indian craton. These Al-rich lithologies (subsequently metamorphosed) have been described as 'paleosols', developed over a 3.3 Ga old Archean gneissic basement and are overlain by Paleoproªterozoic Aravalli quartzite. The paleosol was developed between 2.5 and 2.1, coincident with the globally recognized Great Oxidation Event (GOE). The finding of a 'ferricrete' zone in the upper part of Tulsi Namla section (east of Udaipur) during the study (in addition to earlier reported lithologies) has led to an alternative suggestion of oxygen-rich conditions during paleosol development. The Tulsi Namla paleosol section shows all the features characteristic of a complete paleosol section described from other Archean cratons. The paleosol includes sericite schist with kyanite as the prevalent Al-silicate in the lower part of profile while chloritoid and Fe-oxides typify the Fe-rich upper part. Alumina has remained immobile during the weathering process while Fe and Mn show a decrease in the lower part of the section and an abrupt rise in the upper part, in the ferricrete zone. The field and geochemical data indicate that the Tulsi Namla section is an in situ weathering profile and at least the upper part shows evidence of oxidizing conditions.

4 illus, 32 ref

019622   Ollier C D;Sheth H C (Earth Sciences Dep, Indian Institute of Technology (IIT) Bombay, Powai, Mumbai-400 076, Email: hcsheth@iitb.ac.in) : High deccan durincrusts of India and their significance for the "laterite' issue. J Earth Syst Sci 2008, 117(5), 537-51.

In the Deccan region of western India ferricrete duricrusts, usually described as laterites, cap some basalt summits east of the Western Ghats escarpment, basalts of the low-lying Konkan Plain to its west, as well as some sizeable isolated basalt plateaus rising from the Plain. The duricrusts are iron-cemented saprolite with vermiform hollows, but apart from that have little in common with the common descriptions of laterite. The classical laterite profile is not present. In particular there are no pisolitic concretions, no or minimal development of concretionary crust, and the pallid zone, commonly assumed to be typical of laterites, is absent. A relatively thin, non-indurated saprolite usually lies between the duricrust and fresh basalt. The duricrust resembles the classical laterite of Angadippuram in Kerala (southwestern India), but is much harder. The High Deccan duricrusts capping the basalt summits in the Western Ghat' have been interpreted as residuals from a continuous (but now largely destroyed) laterite blanket that represents in situ transformation of the uppermost lavas, and thereby as marking the original top of the lava pile. But the unusual pattern of the duricrusts on the map and other evidence suggest instead that the duricrusts formed along a palaeoriver system, and are now in inverted relief. The two interpretations lead to different tectonic histories. Duricrust formation involved lateral material input besides vertical elemental exchange. The have reached the stage when the very concepts of laterite and lateritization are hindering in progress in regolith research.

12 illus, 56 ref

019621   Narkhedkar S G;Sinha S K (NO, Indian Institute of Tropical meteorology, Dr. Homi Bhabha Road, Pashan, Pune-411 008, Email: narkhed@tropmet.res.in) : Variational method for objection analysis of scalar variable and its derivative. J Earth Syst Sci 2008, 117(5), 621-35.

In study real time data have been used to compare the standard and triangle method by performing the objective analysis of mean sea level pressure. In the standard method, derivative fields are obtained from the grid point data using finite difference scheme whereas in the triangle method a set of non-overlapping triangles are formed from the observations and the scalar and the spatial derivatives are computed directly at the centroid of each of the non-overlapping triangles. These scalars and their derivatives are then mapped to uniform grids by using the standard method. It has been found that objectively analysed scalar field obtained using standard method is superior to the scalar field derived by the triangle method, whereas the derivative fields produced by triangle method are superior to the derivative fields produced using standard method. A variational objective analysis scheme has been developed and an experiment has been carried out with depression case of June (11-15) 2004. It is found that the new scheme (variational) is able to extract the better parts of both triangle and standard methods. Results of study will be useful in carrying out diagnostic calculations that involve derivative estimates.

10 illus, 1 table, 30 ref

019620   Narasimhan T N (Materials Science and Engineering Dep, University of California, 210 Hearst Memorial Miming Bulding, Berkeley, Ca 94720-1760, USA, Email: tnnarasimhan@lbl.gov) : India's water budget and evpotranspiration. J Earth Syst Sci 2008, 117(3), 237-40.

Some recent analyses of India's water budget are based on information attributed to the Ministry of Water Resources. An examination of the budget components indicates that they imply an evapotranspiration estimate that is significantly lower than what one may expect based on information from other sources. If such is the case, India's water resources situation may be more dire than is otherwise perceived. For, higher evapotranspiration implies correspondingly reduced availability of water for human use. It should be worthwhile to investigate and reconcile the apparent discrepancy between water budget and evapotranspiration, considering the importance of water in the national context.

3 tables, 14 ref

019619   Naithani A K (Geology Dep, , Post Box No. 86, H.N.B. Garhwal University, Srinagar, Garhwal-246 174, Email: ajay_naithani@hotmail.com) : Macro landslide hazard zonation mapping using univariate statistical analysis in a part of Garhwal Himalaya. J Geol Soc India 2007, 70(2), 353-68.

Landslide hazard zonation mapping of the Atagad River catchment was carried out using univariate statistical analysis. Geo-environmental factors which control the stability of slope like lithology, slope morphometry, structure, relative relief, landuse and landcover and hydro-geological conditions are considered as indexes for statistical analysis. The map was prepared by superimposing the terrain evaluation maps using landslide hazard evaluation factors (LHEF) rating scheme and the calculated total estimated hazard (TEHD). The TEHD indicates the net probabilities of instability and is calculated facet wise. On the basis of the TEHD, five categories of landslide hazard zones have been identified, namely, very low hazard, low hazard, moderate hazard, high hazard and very high hazard. Investigation shows that geology, rainfall and human activities have played considerable role in triggering landslides in this part of Himalaya. In the preliminary stage of geotechnical investigation and watershed management, the landslide hazard evaluation factor (LHEF) rating scheme may effectively be used, as this is an economic and rapid hazard assessment technique.

12 illus, 2 tables, 30 ref

019618   Nagarajan R;Armstrong-Altrin J S;Nagendra R; Madhavaraju J;Moutte J (Centro de Investigaciones en Ciencias de la Tierra, Universidad Autonoma del Estado de Hidalgo, Ciudad Universitaria, Carretera Pachuca-Tulancingo km. 4.5, Pachuca, Hidalgo, 42184, Mexico, Email: altrina@uaeh.reduaeh.mx) : Petrography and geochemistry of terrigenous sedimentary rocks in the neoproterozoic rabanpalli formation, Bhima basin, Southern india: implications for paleoweathering conditions, provenance and source rock composition. J Geol Soc India 2007, 70(2), 297-312.

Petrographic, major, trace, and rare earth element compositions of quartz arenites, arkoses, and siltstones of Neoproterozoic Rabanpalli Formation of Bhima Basin have been investigated to understand the provenance. The quartz arenites, arkoses, and siltstones have large variations in major element concentrations. For example, quartz arenites and arkoses contain the higher SiO₂ (average with one standard deviation being 97±1, 73±2, respectively) and lower A1₂O₃ (0.95±0.4, 9.6±0.9, respectively) concentrations than siltstones (SiO₂ = 64±4, A1₂O₃ = 14±1), which is mainly due to the presence of quartz and absence of other Al-bearing minerals in relation with rock types. This is also supported by our petrography, since quartz arenites and arkoses contain significant amount of quartz relative to feldspar and lithic fragments. The observed low CIA values and A-CN-K diagram suggest that the sedimentary rocks of Rabanpalli Formation have undergone K-metasomatism. The Co, Ni, Cr, Ba, Zr, Hf, and Th values are higher in siltstones than quartz arenites and arkoses. The Eu/Eu*, (La/Lu)_cn, La/Sc, Th/Sc, Th/Co, Th/Cr, Cr/Th ratios, and Cr, Ni, V, and Sc values strongly suggest that these sediments were mainly derived from the felsic source rocks. This interpretation is also supported by the Th/Sc versus Sc bivariate and La-Th-Sc triangular plots. The rare earth element (REE) patterns of these rocks also support their derivation from felsic source rocks. Further more, these rocks exhibit higher LREE/HREE ratio (8±4) and a significant negative Eu anomaly (0.77±0.16), which indicate the felsic igneous rocks as a possible source rocks.

12 illus, 3 tables, 94 ref

019617   Nagabhushanam P;Sangurmath P;Patil M L; Sukhija B S (NO, National Geophysical Research Institute, Habshiguda, Uppal Road, Hyderabad-500 606, Email: pnbngri@gmail.com) : Ancient gold mining activity in the Hutti-Muski greenstone belt, Karnataka, India: radiocarbon perspective. Curr Sci 2008, 95(3), 389-91.

Present gold-producing centres of India have witnessed ancient and modern mining activities. The presence of wood logs, ash, charcoal and pottery in ancient gold mines of Kolar, Hutti and Uti suggests fire setting was the main mode of gold exploitation of ancient miners. In the absence of historical records pertaining to the episodes of ancient mining activity in Karnataka, wood material found in the ancient gold workings were used to constrain the episodes of mining activity. We have Radiocarbon (¹⁴C) dated a wood log from the Uti gold mines, which reveals that the ancient mining activity here dates back to AD 660-780. This date from Uti mine together with the earlier published ¹⁴C dates from Kolar fields imply that the ancient gold mining activity was contemporaneous at these places, while the Hutti fields were exploited during the early part of the Christian era.

2 illus, 1 table, 16 ref

019616   Litta A J;Mohanty U C (Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110 016, Email: mohanty@cas.iitd.ernet.in) : Simulation of a severe thunderstorm event during the field experiment of STORM programme 2006, using WRF-NMM model. Curr Sci 2008, 95(2), 204-15.

In the study, an attempt has been made to simulate one thunderstorm event that occurred on 20 May 2006 at Kolkata (22.52°N, 88.37°E) during the field experiment of STORM 2006, using Non-hydrostatic Mesoscale Model (NMM) core of the Weather Research and Forecasting (WRF) system with different initial conditions. This model has been developed by the National Oceanic and Atmospheric Administration/National Centers for Environment Prediction. The model results are validated with STORM field experiment data. The model performed well in capturing stability indices, which act as indicators of severe convective activity along with the thunderstorm-affected parameters as in the observations. The results of these analyses show that the 3 km WRF-NMM has better capability when it comes to thunderstorm simulation. Suggests that high-resolution models have the potential to provide unique and valuable information for severe thunderstorm forecasters.

15 illus, 3 tables, 35 ref

019615   Lai S C (State Key Laboratory of Continental Dynamics, Geology Dep, Northwest Univ, Xi'an City, Shaanxi Province, P.R. China 710069, Email: shaocong@nwu.edu.cn) : Geochemistry and tectonic significance of the ophiolite and associated volcanics in the mianlue suture, qinling orogenic belt, China. J Geol Soc India 2007, 70(2), 217-34.

The Mianlue suture is a component of Qinling orogenic belt, marking the final position of collision between the North and South China Blocks. The suture contains a complicated ophiolitic complex with many slabs of different tectono-stratigraphic units. The ophiolite, mainly distributed in the Pipasi and the Zhuangke areas, are composed of ultrabasic rocks, like harzburgites and dunites, which exhibit LREE depletion with remarkable positive Eu anomaly, and diabase dyke swarms that show LREE enrichment but slightly negative Eu anomaly. Metamorphosed volcanic rocks can be divided into three groups in terms of their REE geochemistry and trace element ratios of Ti/V, Th/Ta, Th/Yb and Ta/ Yb. The first group is the MORB-type basalt with LREE depletion, representing fragments of oceanic crust and implying an association of MORB-type ophiolite and a proto-Tethyan Qinling Ocean between Qinling and South China Block during middle Paleozoic-early Mesozoic times. The second group is the oceanic island basalt assemblage, and the third is the island arc volcanic rocks including tholeiitic basalt and a large amount of calc-alkaline intermediate-acidic volcanic rock associations. These facts indicate that the Mianlue ophiolite represents an ocean basin that experienced evolution from Devonian to Permian, and the Qinling terrane became an independent lithospheric microplate during the late Paleozoic-early Mesozoic.

12 illus, 6 tables, 30 ref

019614   Khare N;Chaturvedi S K (National Centre for Antarctic and Ocean Research, Ocean Development De, , Headland Sada, Vasco - da - Gama, Goa-403 804) : Clay layer atop coral sand at shallow depth off nancowry (Andaman & Nicobar). Bull envir Sci 2006, 24(1), 49-52.

In order to assess the post tsunami impact on marine environment, a multi disciplinary oceanographic cruise was launched on board ORV Sagar Kanya along the tsunami hit west and east Indian coast, Bay of Bengal and Andaman & Nicobar regions immediately after the tsunami events of December 26, 2004. The sediment samples collected off Nancowry (Andaman & Nicobar) at 18 m water depth reveals a layer of 3 cm thick fine sediments atop coral sand. The presence of fine sediments in shallow coral environment indicates its origin away from its present location that have been eroded, transported and deposited at present location during tsunami. To arrive at conclusive results detailed micropaleontological and sedimentological study is envisaged.

2 illus, 6 ref

019613   Israil M;Tyagi D K;Gupta P K;Shri Niwas (Earth Sciences Dep, Indian Institute of Technology Roorkee, Roorkee-247 667, Email: mohdfes@iitr.ernet.in) : Magnetotelluric investigations for imaging electrical structure of Garhwal Himalayan corridor, Uttarakhand, India. J Earth Syst Sci 2008, 117(3), 189-200.

Magneto elluric investigations have been carried out in the Garhwal Himalayan corridor to delinªeate the electrical structure of the crust along a profile extending from Indo-Gangetic Plain to Higher H malayan region in Uttarakhand, India. The profile passing through major Himalayan thrusts: Himalayan Frontal Thrust (HFF), Main Boundary Thrust (MBT) and Main Central Thrust (MCT), is nearly perpendicular to the regional geological strike. Data processing and impedance analysis indicate that out of 44 stations MT data recorded, only 27 stations data show in general, the validity of 2D assumption. The average geoelectric strike, N70°W, was estimated for the profile using tensor decomposition. 2D smooth geoelectrical model has been presented, which provides the electrical image of the shallow and deeper crustal structure. The major features of the model are (i) a low resistivity (< 50 Ωm), shallow feature interpreted as sediments of Siwalik and Indo-Gangetic Plain, (ii) highly resistive (> 1000 Ωm) zone below the sediments at a depth of 6 km, interpreted as the top surface of the Indian plate, (Hi) a low resistivity (< 10 Ωm) below the depth of 6 km near MCT zone coincides with the intense micro-seismic activity in the region. The zone is interpreted as the partial melting or fluid phase at mid crustal depth. Sensitivity test indicates that the major features of the geoelectrical model are relevant and desired by the MT data.

9 illus, 2 tables, 37 ref

019612   Gogoi K;Dutta M N;Das P K (Applied Geology Dep, Dibrugarh Univ, Dibrugarh-786 004, Email: duttamn2000@yahoo.co.in) : Source rock potential for hydrocarbon generation of makum coals, upper Assam, India. Curr Sci 2008, 95(2), 233-9.

The Makum Coalfield is the most important coalfield vin Northeast India as far as coal resources are concerned. An attempt has been made to evaluate the possibility of coal as a source material for oil and gas generation. Twenty-five coal samples were collected from different collieries of the Makum Coalfield and have been analysed using Rock-Eval and vitrinite reflectance with coal petrography. It has been observed that the total organic matter content of the Makum Coalfield varies between 59.11 and 84.55% and the hydrogen indices of the studied samples ranges from 150 to 354 mg Hc/g Corg and contain predominantly type II kerogen. Vitrinite reflectance (0.49-0.86 Ro%) studies reflect that the maturity regime of kerogen falls within the oil-generation window. Hydrogen indices and T_max reflect that the coals are immature and fall in the zone of 40% type II kerogen. The relationship between atomic H/C and atomic O/C reflects that the coals are rich in vitrinite and are of type III kerogen. The higher hydrogen indices reflect increasing amount of lipid-rich material in the Makum Coalfield, either from cutinite, resinite, exinite (terrestrial macerals) or from marine algal materials. Kerogen is type II or type III, mainly gas-prone and tends to be immature with subordinate oil-generation potential.

7 illus, 3 tables, 31 ref

019611   Deore A C (Plant Metabolic Engineering Group, Reliance Life Sciences, Dhirubhai Ambani Life Sciences Centre, Thane-Belapur Road, R-282, Rabale, Navi Mumbai-400 701, Email: ts_johnson@relbio.com) : Occurrence of vivipary in Jatropha curcas L.. Curr Sci 2008, 95(3), 321-2.

^ssc1 illus, 5 ref

019610   Deb S K;Srovastava T P;Kishtawal C M (Atmospheric Sciences Div, Meteorology and Oceanography Group, Space Applications Centre, Ahmedabad-380 015, Email: sanjib_deb@rediffmail.com) : WRF model performance for the simulation of heavy precipitating events over Ahmedabad during Agust 2006. J Earth Syst Sci 2008, 117(5), 589-602.

The summer monsoon season of the year 2006 was highlighted by an unprecedented number of monsoon lows over the central and the western parts of India, particularly giving widespread rainfall over Gujarat and Rajasthan. Ahmedabad had received 540.2 mm of rainfall in the month of August 2006 against the climatological mean of 219.8 mm. The two spells of very heavy rainfall of 108.4 mm and 97.7 mm were recorded on 8 and 12 August 2006 respectively. Due to meteorological complexities involved in replicating the rainfall occurrences over a region, the Weather Research and Forecast (WRF-ARW version) modeling system with two different cumulus schemes in a nested configuration is chosen for simulating these events. The spatial distributions of large-scale circulation and moisture fields have been simulated reasonably well in this model, though there are some spatial biases in the simulated rainfall pattern. The rainfall amount over Ahmedabad has been underestimated by both the cumulus parameterization schemes. The quantitative validation of the simulated rainfall is done by calculating the categorical skill scores like frequency bias, threat scores (TS) and equitable threat scores (ETS). In the' KF scheme has outperformed the GD scheme for the low precipitation threshold.

12 illus, 2 tables

019609   Datt P;Srivastava P K;Negi P S;Satyawali P K (Snow and Avalenche Study Establishment (SASE), Research & Development, , Chandigarh, Email: datt-Prem@rediffmail.com) : Surface energy balance of seasonal snow cover for snow-melt estimation in N-W Himalaya. J Earth Syst Sci 2008, 117(5), 567-73.

Study describes time series analysis of snow-melt, radiation data and energy balance for a seasonal snow cover at Dhundi field station of SASE, which lies in Pir Panjal range of the N-W Himalaya, for a winter season from 13 January to 12 April 2005. The analysis shows that mean snow surface temperature remains very close to the melting temperature of snow. It was found close to -1°C for the complete observational period which makes the snow pack at Dhundi moist from its beginning. The average air temperature over this period was found to be 3.5°C with hourly average variation from -5.5°C to 13°C. The snow surface at this station received a mean short wave radiation of 430 VV m^-2, out of which 298 W m^-2 was reflected back by the snow surface with mean albedo value of 0.70. The high average temperature and more absorption of solar radiation resulted in higher thermal state of the snowpack which was further responsible for faster and higher densification of the snowpack. Net radiation energy was the major compoªnent of surface energy budget with a mean value of 83 W m^-2. Bulk transfer model was used to calculate turbulent fluxes. The net energy was utilized for satisfying cold content and snow-melt by using measured snow surface temperature and density of snow pack. The mean square error between calculated and measured daily snow-melt was found to be approximately 6.6 mm of water equivalent.

4 illus, 14 ref

019608   Dasgupta U;Jain A D (NO, , Hindustan Oil Exploration Company Limited, Lakshmi Chambers, 192 St. Mary's Road, R.A. Puram, Chennai-600 018, Email: udyan_49@rediffmail.com) : Surface geochemical survey over part of the Pranhita-Godavari basin and its impact on the hydrocarbon prospects of the basin. J Geol Soc India 2007, 70(2), 187-93.

The Pranhita-Godavari Basin is a large intercratonic Gondwana Basin located in the eastern part of Peninsular India. It essentially represents a NW-SE trending failed rift and is separated into three sub-basins, viz. Godavari, Kothagudem and Chintalapudi sub-basins, by transverse transfer zones. Though a number of sizeable coalfields are located within the basin, it is essentially unexplored from hydrocarbon point of view. Hydrocarbon source-rock analyses carried out on samples from outcrops and shallow bore-holes (60 m - 500 m depths) show low to moderate maturity. In order to investigate the hydrocarbon potential of the basin, a reconnaissance surface geochemical survey was carried out over an approximately 5000 sq km area covering most of the Godavari sub-basin, which is the largest of the three. The results of the study indicate that the basin (within the area of the survey) is actively leaking measurable quantities of light hydrocarbons to the surface and that all the anomalies are full spectrum anomalies of petrogenic origin. Three regions of significant anomalies can be outlined; one is a gas-prone trend whilst two are oil and gas-prone.

6 illus, 5 ref

019607   Das S;Ashrit R;Iyengar G R;Mohandas S;Das Gupta M;George J P;Rajagopal E N;Dutta S K (SAARC Meteorological Research Centre, , Dhaka, Bangaladesh, Email: somesh07@yahoo.com) : Skills of different mesoscale models over Indian region during monsoon season: forecast errors. J Earth Syst Sci 2008, 117(5), 603-20.

Performance of four mesoscale models namely, the MM5, ETA, RSM and WRF, run at NCMRWF for short range weather forecasting has been examined during monsoon-2006. Evaluation is carried out based upon comparisons between observations and day-l and day-3 forecasts of wind, temperªature, specific humidity, geopotential height, rainfall, systematic errors, root mean square errors and specific events like the monsoon depressions. It is very difficult to address the question of which model performs best over the Indian region? An honest answer is 'none'. Perhaps an ensemble approach would be the best. It can be stated that in general, (i) the WRF is able to produce best All India rainfall prediction compared to observations in the day-l forecast and, the MM5 is able to produce best All India rainfall forecasts in day-3, but ETA and RSM are able to depict the best distribution of rainfall maxima along the west coast of India, (ii) the MM5 is able to produce least RMSE of wind and geopotential fields at most of the time, and (iii) the RSM is able to produce least errors in the day-l forecasts~of the tracks, while the ETA model produces least errors in the day-3 forecasts.

12 illus, 2 tables, 32 ref

019606   Combalicer E A;Lee S H;Ahn S;Kim D Y;Im S (Forest Sciences Dep, Research institute for Agriculture & Life Sciences, College opf Agricu, San 56-1, Silim-dong, Gwanak-gu Seoul, 151 921, Korea, Email: junie@snu.ac.kr) : Comparing groundwater recharge and base flow in the bukmoongol small-forested watershed, Korea. J Earth Syst Sci 2008, 117(5), 553-66.

Groundwater recharge and base flow using different investigated methods are simulated in the 15-ha Bukmoongol small-forested watershed located at the southern part of Korea. The WHAT system, PART, RORA, PULSE, BFI, and RAP software are used to estimate groundwater recharge or base flow and base flow index from the measured streamflow. Results show that about 15-31 per cent of annual rainfall might be contributed for base flow. The watershed groundwater recharge proportions are computed to about 10-21 per cent during the wet period and 23-32 per cent for the remainder periods. Mean annual base flow indices vary from 0.25 to 0.76 estimated using different methods. However, the study found out that all methods were significantly correlated with each other. The similarity of various methods is expressed as a weighted relationship provided by the matrix product from the principal component analysis. Overall, the BFI and WHAT software appeared consistent in estimating recharge or base flow, and base flow index under Korea's conditions. The case study recommends the application of different models to other watersheds as well as in low-lying areas where most observation groundwater wells are located with available streamflow data.

6 illus, 4 tables, 53 ref

019605   Bidokhti A A;Khoshsima M;Sabetghadam S; Khalesifard H M (NO, Institute of Geophysics, University of Tehrun, Tehrum, P.O. Box: 14155-6466, Iran, Email: bidokhti@ut.ac.ir) : Estimation of urban mixed layer height in Zanjan using LIDAR observations and numerical modeling. J Earth Syst Sci 2008, 117(6), 925-34.

Air pollution predictions often require the height of atmospheric mixed layer in time especially in big cities. Here, the variation of the height of this layer is estimated from direct measurements and also from a numerical forecast model with a high resolution boundary layer scheme. The height of the daytime mixed layer for the city of Zanjan (48.5°N, 36.7°E, 1700 m above sea level) is measured using a LIDAR (532 nm) system, which works based on aerosols scattering of laser light. The mixed layer height (Z_i) for Zanjan city, well above mean sea level compared to other major cities in the world is found to be between 1.4 km typically in spring and 2.2 km in summer, for synoptic calm conditions. Also the MM5 forecast model with a proper boundary layer scheme (MRF) is used to estimate Z_i which shows rather good agreement with direct observations using the LIDAR system. The entrainment zone of the mixed layer was also found to undergo some occasional temporal growth that may be attributed to shear instability that led to more mixed layer growth.

12 illus, 1 table, 30 ref

019604   Bhat G S;Arunchandra S C (Center for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore-560 012, Email: bhat@caos.iisc.ernet.in) : Measurement of the surface energy budget over a land surface during the summer monsoom. J Earth Syst Sci 2008, 117(6), 911-23.

The measurement of surface energy balance over a land surface in an open area in Bangalore is reported. Measurements of all variables needed to calculate the surface energy balance on time scales longer than a week are made. Components of radiative fluxes are measured while sensible and latent heat fluxes are based on the bulk method using measurements made at two levels on a micrometeorological tower of 10 m height. The bulk flux formulation is verified by comparing its fluxes with direct fluxes using sonic anemometer data sampled at 10 Hz. Soil temperature is measured at 4 depths. Data have been continuously collected for over 6 months covering pre-monsoon and monsoon periods during the year 2006. The study first addresses the issue of getting the fluxes accurately. It is shown that water vapour measurements are the most crucial. A bias of 0.25% in relative humidity, which is well above the normal accuracy assumed by the manufacturers but achievable in the field using a combination of laboratory calibration and field intercomparisons, results in about 20 W m^-2 change in the latent heat flux on the seasonal time scale. When seen on the seasonal time scale, the net longwave radiation is the largest energy loss term at the experimental site. The seasonal variation in the energy sink term is small compared to that in the energy source term.

11 illus, 1 table, 29 ref

019603   Baruah S;Hazarika D (Geoscience Div, North-East Institute of Science and Technology (CSIR), Jorhat-785 006, Email: saurabhb_23@yahoo.com) : GIS based tectonic map of northeastern India. Curr Sci 2008, 95(2), 176-7.

2 illus, 8 ref

018621   Vinoj V;Satheesh S K;Krishna Moorthy K (Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore-560 012) : Aerosol characteristics at a remote island: minicoy in southern Arabian sea. J Earth Syst Sci 2008, 117(S1), 389-97.

Extensive measurements of aerosol optical and microphysical properties made at a remote island, Minicoy in southern Arabian Sea for the period (February 2006-March 2007) are used to characterize their temporal variability and Black Carbon (BC) mass mixing ratio. Large decrease in aerosol BC (from ~800ng m^-3 to ~100ng m^-3) was observed associated with change in airmass characteristics and monsoon rains. The total aerosol mass varied between ~80 and 20 μg m^-3. Though the total mass fell drastically, a slight increase in super micron mass was observed during the June-August period associated with high winds. The mass fraction of Black Carbon aerosols during the prevalence of continental airmass is found to be ~1.2% of the composite aerosols, which is much lower than the values reported earlier for this region.

9 illus, 49 ref

018620   Vasudev V N;Chadwick B (NO, , "JAYA", 120/45, 3rd Block, 6th Cross, 6th main, Tyagaraja Nagar, Bangalore-560 028, Email: vasu.sacredtrust@gmail.com) : Lithology and structure of the auriferious hutti schist belt, Northern Karnataka: implications of rneoarchaean oblique convergence in the Dharwar craton, South India. J Geol Soc India 2008, 71(2), 239-56.

Chronological relationships between quartz-carbonate vein systems (locally auriferous) and pervasive schistosity and linear fabrics show that a tectonic continuum of NE-SW shortening, here labelled D1, gave rise to a large-scale anticline-syncline pair in the E of the schist belt and an apparent tectonic discontinuity in the NE of the belt that separates the SW younging Palkanmardi fining-up sequence and metabasalts with a total strike-normal thickness of ca. 3.5 km from the metabasalts, felsic volcanic sheets and the Gagalgatta complex in the central and southern parts of the belt which together young NE and have a total strike-normal thickness of ca. 15 km. This anomalous thickness of ca. 15 km is consistent with tectonic thickening in other Neoarchaean schist belts in the craton, but no thrusts were proved in the Hutti belt. Regional HT-LP amphibolite facies metamorphism was closely tied to emplacement of granite s. I. within and adjacent to the schist belt contemporaneous with, but also outlasting, the D1 continuum. Conjugate sets of small-scale shear zones discordant to D1 schistosity suggest that D1 deformation became progressively brittle and localised. The reason for a major post-D1 swing in D1 schistosity in the NW of the belt is unclear. The sheet form of the granites (including granodiorite) within and adjacent to the schist belt, their chronological spectrum of emplacement relative to deformation, the unstable volcanic and depositional setting of the schist belt, the anomalous strike-normal thickness in the west of the belt, and published geochemical data of the metabasalts indicative of an island-arc setting are consistent with the position of the Hutti schist belt in the accretionary complex in our published model of Neoproterozoic oblique convergence in the Dharwar craton.

6 illus, 38 ref

018619   Umar R;Khan M M A;Ahmed I;Ahmed S (Geology Dep, Aligarh Muslim Univ, Aligarh-202 002) : Implications of Kali-Hindon inter-stream aquifer water balance for groundwater management in western Uttar Pradesh. J Earth Syst Sci 2008, 117(1), 69-78.

An attempt has been made to calculate a water balance for the Kali-Hindon inter-stream region. Various inflows and outflows to and from the aquifer have been calculated. The recharge due to rainfall and other recharge parameters such as horizontal inflow, irrigation return flow and canal seepage were also evaluated. Groundwater withdrawals, evaporation from the water table, discharge from the aquifer to rivers and horizontal subsurface outflows were also estimated. The results show that total recharge into the system is 148.72 million cubic metres (Mcum), whereas the total discharge is 161.06 Mcum, leaving a deficit balance of -12.34Mcum. Similarly, the groundwater balance was evaluated for the successive four years. The result shows that the groundwater balance is highly sensitive to variation in rainfall followed by draft through pumpage. The depths to water level are shallow in the canal-irrigated northern part of the basin and deeper in the southern part. The pre-monsoon and post-monsoon water levels range from 4.6 to 17.7m below ground level (bgl) and from 3.5 to 16.5m bgl respectively. It is concluded that the groundwater may be pumped in the canal-irrigated northern part, while withdrawals may be restricted to the southern portion of the basin, where intense abstraction has led to rapidly falling water table levels.

6 illus, 3 tables, 14 ref

018618   Umar R;Ahmed I;Alam F (Geology Dep, Aligarh Muslim Univ, Aligarh-202 002, Email: rashidumar@rediffmail.com) : Mapping groundwater vulnerable zones using modified DRASTIC approach of an alluvial aquifr in parts of central Ganga plain, Western Uttar Pradesh. J Geol Soc India 2009, 73(2), 193-201.

A detailed hydrogeological and hydrochemical study was carried out in Yamuna-Krishni sub-basin which is a part of the vast central Ganga plain. Groundwater is the major source of water supply for agricultural, domestic and industrial uses. The excess use of groundwater has resulted in depletion of water levels. The groundwater quality, too, has deteriorated in areas dominated by industrial activity. This has led to the preparation of a groundwater vulnerability map in relation to contamination. Groundwater vulnerability maps are valuable derivative maps that show, quantitatively or qualitatively, certain characteristics of the sub-surface environment that determine vulnerability of groundwater to contamination. The modified DRASTIC method was used to prepare vulnerability map. The parameters like depth to water, net recharge, aquifer media, soil media, impact of vadose zone, hydraulic conductivity and land use pattern, owing to its bearing on groundwater regime, were considered to prepare vulnerability map. The vulnerability index is computed as the sum of the products of weight and rating assigned to each of the input considered as above. The vulnerability index ranges from 140 to 180, and is classified into four classes i.e. 140-150, 150-160, 160-170 and 170-180 corresponding to low, medium, high and very high vulnerability zones respectively. Using this index, a groundwater vulnerability potential map was generated which shows that 7%, 40% and 53% of the study area falls in low, medium and high to very high vulnerability zones respectively. The map, thus generated, can be used as a tool for protection and management of aquifers from contamination.

6 illus, 4 tables, 12 ref

018617   Thompson B;Gnanaseelan C;Parekh A;Salvekar P S (NO, Indian Institute of Tropical Meteorology, Pashan, Pune-411 008, Email: seelan@tropmet.res.in) : North Indian ocean warming and sea level rise in an OGCM. J Earth Syst Sci 2008, 117(2), 169-78.

The variability in the long-term temperature and sea level over the north Indian Ocean during the period 1958-2000 has been investigated using an Ocean General Circulation Model, Modular Ocean Model version 4. The model simulated fields are compared with the sea level observations from tide-gauges, Topex/Poseidon (T/P) satellite, in situ temperature profile observations from WHOI moored buoy and sea surface temperature (SST) observations from DS1, DS3 and DS4 moored buoys. It is seen that the long (6-8 years) warming episodes in the SST over the north Indian Ocean are followed by short episodes (2-3 years) of cooling. The model temperature and sea level anomaly over the north Indian Ocean show an increasing trend in the study period. The model thermocline heat content per unit area shows a linear increasing trend (from 1958-2000) at the rate of 0.0018 x 10¹¹ J/m² per year for north Indian Ocean. North Indian Ocean sea level anomaly (thermosteric component) also shows a linear increasing trend of 0.31 mm/year during 1958-2000.

9 illus, 2 tables, 30 ref

018616   Thomas J;Riyazulla M S;Subramanian S;Vasudev V N;Gundewar C S (Indian Bureau of Mines, G G Palaya, Bangalore-560 022, Email: rodlbng@vsnl.net) : Electron microprobe and mineralogical study on cobalt bearing sulphide from the kalyadi copper mine, Hassan district, Karnataka. J Geol Soc India 2008, 71(2), 257-60.

Cobalt mineralisation in the Kalyadi copper-cobalt deposit in the Hassan district, Karnataka, is mostly in sulphidic banded, feldspathic cherty quartzite. Electron microprobe study conducted on sulphide concentrates from this deposit revealed that cobalt up to 3.21 wt% is present exclusively in pyrite grains, whereas it is absent in chalcopyrite and arsenopyrite. From this, it infers that pyrite crystallized first, followed by chalcopyrite and arsenopyrite with most cobalt present in the mineralizing system replacing Fe in the paragenetically early-formed pyrite, thereby rendering the system deficient in cobalt during later crystallization of chalcopyrite and arsenopyrite.

6 illus, 12 tables, 8 ref

018615   Tewari R C;Singh D P (Geology Dep, Dharam Samaj College, Aligarh-202 001, Email: ram_tewari@yahoo.com) : Permian gondwana palaeocurrents in bellampalli coal belt of Godavari valley basin, Andhra Pradesh and palaeogeographic implications. J Geol Soc India 2008, 71(2), 266-70.

The Permian Gondwana sequence of Bellampalli coal belt of Godavari valley basin comprises Barakar, Barren Measures and Raniganj Formations in ascending order. Lithofades composition suggests a slight decline in the bulk sandstone at the expense of fine elastics, through time from Barakar up to Raniganj Formation. Paleocurrent analysis based on 379 trough cross beds indicate that the Permian Gondwana formations of Bellampalli area were deposited on a northwesterly and northeasterly paleoslope. The resultant mean paleocurrent at formation levels is 351° ± 17° for Barakar, 13° ± 36° for Barren Measures and 348°±36° for the Raniganj, respectively. The close harmony between northwesterly paleoslopes here deduced, the Permian paleoslopes in the southern parts and the NW-SE structural trend of Godavari valley is indicative of rift valley filling of the area atleast during early Permian. It is suggested that the bulk of sediments of given area were supplied from the southerly and southeasterly situated provenance.

3 illus, 1 table, 14 ref

018614   Suresh Babu S;Satheesh S K;Krishna Moorthy K; Dutt C B S;Nair V S;Alappattu D P;Kunhikrishnan P K (Space Physics Laboratory, VSSC, Trivandrum-695 022) : Aircraft measurements of aerosol black carbon from a coastal location in the north-east part of Peninsular India during ICARB. J Earth Syst Sci 2008, 117(S1), 263-71.

During the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) over India, high-resolution airborne measurements of the altitude profiles of the mass concentrations (M_B) of aerosol black carbon (BC) were made off Bhubaneswar (BBR, 85.82°E, 20.25°N), over northwest Bay of Bengal, in the altitude region upto 3 km. Such high-resolution measurements of altitude profiles of aerosols are done for the first time over India. The profiles showed a near-steady vertical distribution of M_B modulated with two small peaks, one at 800m and the other at ~ 2000m. High resolution GPS (Global Positioning System) sonde (Vaisala) measurements around the same region onboard the research vessel Sagar Kanya (around the same time of the aircraft sortie) revealed two convectively well mixed layers, one from ground to ~ 700 m with an inversion at the top and the other extends from 1200m to ~ 2000m with a second inversion at ~ 2200m and a convectively stable region in the altitude range 700-1200 m. The observed peaks in the M_B profile are found to be associated with these temperature inversions. In addition, long-range transport from the Indo-Gangetic Plain (IGP) and deserts lying further to the west also influence the vertical profile of BC. Latitudinal variation of M_B showed a remarkable land ocean contrast at the 500 m altitude (within the well mixed region) with remarkably lower values over oceans, suggesting the impact of strong sources over the mainland. However, above the ABL (at fSOOrn), the latitudinal variations were quite weak, and this appears to be resulting from the impact of long-range transport. Comparison of the altitude profiles of M_B over BoB off BBR with those obtained during the earlier occasion over the inland stations of Hyderabad and Kanpur showed similarities above ~ 500 m, with M_B remaining around a steady value of ~1 μg m^-3. However, large differences are seen within the ABL. Even though the observed M_B values are not unusually high, their near constancy in the vertical column will have important implications to radiative forcing.

6 illus, 1 table, 31 ref