001392   Sachan H K;Mukherjee B K (NO, Wadia Institute of Himalayan Geology, Dehra Dun-248 001) : Evidences of fluid-reequilibration in Blueschist rocks from Shergol ophiolitic melange, Indus suture zone, Ladakh. Himalayan Geol 2001, 22(2), 127-33.

The regular shaped fluid inclusions are very often in both type of earlier folded and late planar quartz veins, whereas the highly irregular shaped inclusions are present only in the earliest folded quartz veins. The regular inclusions have moderate salinity (9.8-7.1 wt% NaCl) and homogenized to liquid at 140-180°C. These veins were folded during compressional domain. It seems that the original inclusions in the earlier formed veins might be trapped during subsequent to subduction. The irregular shaped inclusions with implosion texture could have formed under condition of high internal underpressure in decompressional regime. The regular shaped inclusions were trapped in both types of veins during the late stage of exhumation process.

5 illus, 25 ref

001391   Roy A;Hanuma Prasad M;Chore S A;Viswakarma L L (Geological Suvey of India, , Seminary Hills, Nagpur-400 006) : Granulite facies BIF from the betul supracrustal belt, Central India. J Geol Soc India 2003, 62(5), 635-40.

Granulite facies BIF enclaves, hosted in a maficultramafic intrusive complex, were recognized from the northern part of the Proterozoic Betul supracrustal belt in the Central Indian Tectonic Zone (CITZ). The petrographic study reveals three different stages of metamorphic mineral growth represented sequentially by orthopyroxene-clinopyroxene-plagioclase₍₁₎, rims of plagioclase₍₂₎ on magnetite and finally by coronal garnet. The mineral paragenesis suggests a post-peak decompression and final cooling.

^ssc 5 illus, 16 ref

001390   Rau T K;Soni M K (Project Diamond, OP, A.P. Geological Survey of India, Southern Region, Hyderabad-500 068) : Diamondiferous vidhyan conglomerates and their provenance - a critical study. Indian Mineralogist 2003, 37(2), 22-30.

The northwesterly provenance as indicated by the study of palaeocurrent directions coupled with the higher percentage of germ quality diamonds in the conglomerates (55%), compared to those in the Majhgawan and Hinota kimberlite pipes (38%) suggests that the source for the former could be other than the latter. Further, it is interesting to note that the kimberlite indicator minerals such as chrome diopside, Cr-Mg spinels, picroilmenite and pyrope garnet are absent in the matrix part of these conglomerates, perhaps as a result of abrasion they suffered due to the long transportation by the streams and/or the winnowing action on the beach. Thus, in all probability, the provenance for the conglomerate diamonds could be located in the northwest in the Bundelkhand granite terrain that borders the northern margin of the Vindhyan Basin. Encouraged by this contention, the stream sediment sampling carried out in this part of the granitic terrain revealed the presence of pyrope garnets and microdiamonds in a number of locations, warranting a detailed probe to locate the primary source rocks for the conglomerate diamonds.

1 illus, 1 table, 9 ref

001389   Ramalingam G;Renganathan M;Kanishkan B (Geological Survey of India, , Shillong) : Geothermal anomaly along the vellar river in the Agniar basin, Tamil Nadu. Indian Mineralogist 2003, 37(2), 43-9.

The Agniar basin spreads over an area of 5000 sq km and is bounded by the Cauvery basin on the north and west, the Pambar basin on the south and the Palk Strait in the east. It is drained by the Agniar, Vellar, Ambullar and Maharajasamudram rivers. The studies carried out have brought to light various morphological features and environments. No pre-Quaternary outcrops are met with in the studied area. Different landform of fluvial, marine and fluvio-marine environments have been delineated. The presence of palaeo-shorelines, submerged deltas and strandline are indicative of ecustatic changes. The River Vellar, draining the area has a straight to braided course having sinuosity ratio less than 1.2. Occurrence of bedrock at contrastingly different levels on either banks of the Vellar River, abrupt variation in water quality on either banks and absence of delta in predominantly emerging coast are suggestive of neotectonic activity along the Vellar River and possible source of geothermal anomaly in this area.

9 ref

001388   Raju V S (Ocean Engineering Dep, Indian Institute of Techology Madras, Chennai-600 036) : Towards excellence in geotechnical engineering practice in India. Indian Geotech J 2003, 33(1), 1-78.

Geotchnical investigations, choice of appropriate foundation design and construction of berthing structures, coastal protection works and management of ash ponds have been dealt with. Other areas excavations dewatering like ground water lowering, design of earth structures, geotechnical instrumentation for monitoring and execution and subsequent performance of structures and so on.

^iia56 illus, 3 tables, 26 ref

001387   Rajshekhar C;Reddy P P (Geology and Palaeontology Group, Agharkar Research Institute, G.G. Agarar Road, Pune-41 004) : Late quaternary beach rock formations of Andaman-Nicobar Islands, Bay of Bengal. J Geol Soc India 2003, 62(5), 595-604.

The beach rock formations of sourth Andaman island are characterised by moderately soft to hard, fine to coarse grained/gritty, yellow to light buff coloured calcareous rocks. These rocks containg minute shells of gastropods and bivalves. The foraminifera are common and are dominantly represented by the species of the genus Pararotalia. The ¹⁴C dates of the beach rocks range from 4410-1540 years B.P. The Wandoor beach rock with 1540-1350 years B.P. is younger to the Chidyatapu beach rocks which have been dated 4410-3900 years B/.P. Petriographically, the Andaman beach rocks belong to algal biocalcarenite facies. The carbon isotope ages of the beach rock formations of the Indian Peninsula including Andaman indicate Late Holocene as a major transgressional event.

4 illus, 1 table, 17 ref

001386   Parkash S;Awasthi A K (NO, Wadia Institute of Himalayan Geology, Dehra Dun-248 001) : Slope movement through time at Matli site, Uttarkashi district, Garhwal Himalaya, India. Himalayan Geol 2001, 22(2), 109-20.

Geoscientific studies on landslides often call for instrumentation and monitoring of the potentially unstable and failed slopes in order to understand the time dependent behaviour for risk estimation and for planning appropriate corrective measures. Besides forecasting the long term behaviour of slopes, the studies also help in evaluating the efficacy of existing control measures and the need for possible additional measures. The present study provides feedback from observational data on slope movements through time at one of the problematic sites in Bhagirathi valley of Garhwal Himalaya in India. The Himalaya has experienced major landslide damages mainly due to fragile topography, geodynamic and climatic conditions. Furthermore, unscientific human interference with the nature has augmented this problem thereby posing risks to life, economy and environment. To reduce these risks, a real-time measurement system for three dimensional displacement studies of the potentially unstable and failed slopes has been attempted and presented herewith. A monitoring system has been setup so as to have periodical spatio-temporal information on slope displacements. An infra-red beam based Electronic Distance Meter (EDM) has been used for measuring such displacements of the sliding mass.

10 illus, 4 tables, 19 ref

001385   Oatney E M;Virdi N S;Yeats R S (NO, Oregon State University, Corvallis, OR 97331, USA) : Contribution of the Trans-Yamuna active fault system toward hangingwall strain release above the decollement, Himalayan foothills of Northwest India. Himalayan Geol 2001, 22(2), 9-27.

Documented active faults north of the Himalayan Front Thrust suggest that strain release in the western Himalaya is distributed over a broad area above the decollment rather than all at the front. It uses paleoseismology to document and discuss the contribution of the Trans-Yamuna active fault system in the northwestern Doon Valley of the Indian Himalayan foothills toward distributed strain release. This east-west fault system in subparallel to and crosses the Main Boundary thrust near the structural transition from the Nahan salient to the Dehra Dun reentrant. The Trans-yamuna active fault system may terminate to the east at a lateral ramp of the Main Boundary thrust. A south-side-up, relatively linear fault trace with variable fault dips suggests that the fault system is high-angle reverse with a component of strike-slip. It is subdivided into the Sirmurital, Dhamaun, and Bharli faults, which probably connect at depth. The Dhamaun fault is exposed where it cuts the late Holocene upper Bhatrog terrace deposit of the Giri River. A paleoseismic investigation of the Sirmurital fault at another Giri River terrace did not expose the fault, but it suggests that late Holocene terrace deposits there may be folded into a syncline parallel to fault strike. The fold axis of the syncline continues into bedrock to the west. Earthquakes in 1803, 1905 or perhaps earlier may have contributed to folding of the fine-grained sediments within this terrace deposit. The Trans-Yamuna active fault system is a secondary hangingwall fault that may accommodate some strain release above the decollement during large-magnitude earthquake. Strike-slip may be related to the lateral translation of the Karakoram fault block and east-west extension of the southern Tibet block as a result of oblique convergence between the Indian and Eurasian plates in the northwest Himalaya.

14 illus, 13 ren

001384   Nanda A C;Shukla S D (NO, Wadia Institute of Himalayan Geology, Dehra Dun-248 001) : Fossil giraffid from the middle Siwalik subgroup near Dehra Dun. Himalayan Geol 2001, 22(2), 121-5.

Middle Siwalik vertebrate fossils are generally scarce in the Indian Siwalik except in the Haritalyanagar area of Himachal Pradesh. In the area south of Dehra Dun, the fossils are very rare despite good exposures. The lower dentition of a Giraffid was collected in situ from Mohand section of Dehra Dun and is described here as Hydaspitherium megacephalum. Its presence indicates that multistoried sandstone succession which yielded the fossil is an age equivalent to the Dhok Pathan Formation (Middle Siwalik Subgroup). It also indicates a wider geographic province for the taxon.

3 illus, 1 table, 16 ref

001383   Nainwal H C;Prasad C (Geology Dep, HNB Garhwal University, Srinagar (Garhwal)-246 174) : Micro-zonation of slope instability using SMR approach - a case study from Garhwal Himalaya, India. Himalayan Geol 2001, 22(2), 135-46.

The micor-zonation approach for slope stability assessment was carried out for the Kaliasaur and Rudraprayag landslide areas of Alaknanda valley Garhwal Himalaya, in order to obtain useful geotechnical and geomorphological data, which will be useful for planning developmental projects in this region. This micro-zonation is based on quantitative classification of rock masses, following the Slope Mass Rating technique of Romana (1985). The Kaliasaur landslide area has steeper slopes over moderate to highly weathered quartzites. On the other hand, Rudraprayag landslide area has moderate to steep slopes over low to highly weathered phyllites, slates, metavolcanics and quartzites. The bed rocks of Kaliasaur landslides has generally poor to fair RMR, whereas those of Rudraprayag slide area have very poor to poor RMR. The rocks of Kaliasaur area generally have dominant planar and minor wedge failures, whereas in case of Rudraprayag landslide, wedge and planar failures are almost equal. On the basis of Rock Mass and Slope Mass Ratings, relatively various stable and unstable zones of both landslides were identified.

4 illus, 13 tables, 26 ref

001382   Nagumo S (NO, Earthquake Research Institute, University of Tokyo, 1-17-23 Nakane, Meguro, Tokyo 152-0031, Japan) : Thermal tectonics for generating the marginal-sea and the island-arc system. Himalayan Geol 2001, 22(2), 1-8.

The tectonic history of generating the marginal-sea and the island-arc system is modeled by the thermally driven circulation of the partial melts in the partially molten layer in the asthenosphere. The physics of the partial melts flow is similar to the ocean circulation, that is the thermally driven flow in the porous high viscous media. The deepening of the Japan Sea in the Middle Miocene corresponds to the single horizontal circulation in the whole region of the partially molten layer (the 4th mode of the circulation). The tectonic development from the Green tuff Activity (Early-to-Middle Miocene) to the Island-arc Activity (Quaternary) seem to correspond to a systematic change of the predominant mode in the horizontal circulation of the partial-melts flow in the partially molten layer in the asthenosphere.

8 illus, 19 ref

001381   Mukherjee M K (Geological Studies Unit, Indian Statistical Institute, 203, B.T. Road, Kolkata-700 035) : Very low-grade metamorphism vis-a-vis penetrative deformation in the southern Nallamalai fold-fault belt, Cuddapah basin, Andhra Pradesh. J Geol Soc India 2003, 62(5), 535-48.

The grade of metamorphism and its time relationship with penetrative deformation has been investigated in the western half of the soulthern Nallamalai fold-fault belt in the Cuddapah basin using; illite crystallinity (IC) index and microstructure of chlorite-mica aggregates. IC index values ranging between 0.30° Δ2θ and 0.40°Δ2θ (in a set of six samples) indicate lower anchizone (very low grade) metamorphic conditions within a temperature range of 200-250°C. From morphology, orientation and development of chlorite-mica aggregates, an initial pre-deformational but post diagenetic (burial metamorphic) origin of one of the existing two groups of aggregates is favoured. This group later underwent shape modification and growth during deformation and associated progressive metamorphism. The other group of aggregated appears to be entirely synkinematic with the cleavage forming penetrative deformation. Therefore, in the southern Nallamalai fold-fault belt, an early very low-grade burial metamorphism was overprinted by a relatively later low-grade metamorphism accompanying penetrative deformation.

10 illus, 40 ref

001380   Krishna Reddy K;Kozu T (NO, Frontier Observational Researh System for Global Change, Yokohama, Japan) : Measurements of raindrop size distribution over Gadanki during south-west and north-east monsoon. Indian J Radio Space Phys 2003, 32(5), 286-95.

Simultaneous observations of disdrometer and optical rain gauge (at National MST Radar Facility, Gadanki) and their application in rainfall estimation are evaluated. Comparison of rain rate obtained from disdrometer and optical rain gauge in different precipitation events in different seasons show reasonably good agreement between the two instruments. Southern India has two distinct rainfall seasons, namely south-west (S-W) monsoon and north-east (N-E) monsoon periods. Disdrometer data analysis shows a clear seasonal dependence in radar reflectivity factor-rainfall rate (Z-R) relations (i.e. raindrop size distribution characteristics) in S-W monsoon and N-E monsoon periods over Gadanki. It is also found that during S-W monsoon precipitation generally has bigger drops than during N-E monsoon. During the S-W monsoon most of the precipitating could systems are associated with mesoscale convection activities. These precipitating systems are shortlived (≈1-2 h) with high intensity of rainfall.

7 illus, 2 tables, 17 ref

001379   Krishna Reddy (NO, Frontier Research System for Global Change, Yokohama, Japan) : Convective boundary layer information revealed by the lower atmospheric wind profiler over Gadanki, India. Indian J Radio Space Phys 2003, 32(5), 312-9.

A technique for determining the height of the convective atmospheric boundary layer (CBL) with lower atmospheric wind profiler (LAWP) at Gadanki is discussed. The results are qualitatively compared with simultaneous radiosonde observations. Gadanki-LAWP provides continuous CBL height measurements with very good time resolution (5 minutes or less), allowing for detailed understanding of growth and fluctuations of CBL. During dry season, on clear days, a thin enhanced echo layer corresponding to the top planetary boundary layer (PBL) appeared at about 500 m height in the morning and ascended to about 1500 m in the afternoon. Strong upward/downward velocities were observed below the echo layer (or inside PBL), reaching 1.5 km in the afternoon. Two types of strong echo structures were found to appear systematically in the tropical PBL with diurnal variations on clear days during wet season. The first type, the striking appearance of an echo layer ascending from below 300 m (in the morning) to above 3-5 km (in the afternoon), was identified as a diurnal variations on clear days during wet season. The first type, the striking appearance of an echo layer ascending from below 300 m (in the morning) to above 3-5 km (in the afternoon), was identified as a diurnal variation of the top of the mixing PBL. Another typeis an elevated layer echo appearing at 2-3 km height from almost all the times, which seems to be coincided with humidity gradient.

6 illus, 2 tables, 27 ref

001378   Kayal J R;Sagina Ram;Singh O P;Chakraborty P K;Karunakar G (Central Geophysics Div, Geological Survey of India, , 27, J.N. Road, Kolkata-700 016) : The March 1999 Chamoli earthquake in the Garhwal Himalaya: aftershock characteristics and tectonic structure. J Geol Soc India 2003, 62(5), 558-80.

The aftershock sequence of the Chamoli earthquake (m_b 6.3) of March 28, 1999 provides an opportunity to study the aftershock characteristics and the seismotectonic structure in the Garhwal Himalaya. Detailed analysis of the spatial variation, the frequency-magnitude distribution (b-value), the activity decay-rate (p-value) and falt-plane solutions of the aftershocks throw new light of the aftershock characteristics and seismotectonics of the region. The observations suggest that the aftershock generating process and the b- and p- values changed with time, space and magnitude-ranges. The main shock occurred on the Basement Thrust by a thrust-fault mechanism. The aftershocks, on the other hand, are triggered by the seismogenic faults to the south of the Main Central Thrust (MCT) by thrust as well as by strike-slip faulting, and all the events occurred above the plane of detachment.

10 illus, 67 ref

001377   Kamaruzzaman B Y;Rosnan Y;Mohd Lokman H; Shazili N A;Antonina A (Mangrove Research Unit, Institute of Oceanography, University College of Science & Technology Malaysia, 21030 Kuala Terengganu, Terengganu (Malaysia)) : Textural and physical characteristics of the Chukai river estuarine system, Terengganu, Malaysia. Ultra Scient phys Sci 2002, 14(1), 43-52.

Seasonal variation of textural and physical parameters studies such as salinity, temperature, pH, dissolved oxygen, light penetration and total suspended solids have been carried out. Field measurements were carried out twice during dry season (July 1992 and May 1993) and twice during rainy season (September 1992 and February 1993). Oceanographic measurements were made at 11 station along the Chukai river. In general, neither textural nor the physical parameters in the Chukai river varied significantly by the seasonal changes but only showing some relatively lower values in the non-monsoon season compared to the monsoon season. Silt and clay contents of bottom sediment show a decrease in distance towards estuary and may indicates that the particle transport in the study area is mainly influenced by river discharge. The estuary remained marine dominated during non-monsoon season, whereas freshwater dominance prevailed during monsoon season. The temperature of surface and bottom waters are almost uniform or even sometimes they are identical while pH and light penetration has an inverse relationship with salinity and total suspended solids, respectively.

2 illus, 2 tables, 8 ref

001376   Gupta V;Virdi N S;Parkash S (Geography Dep, Fatih University, 34900, Istanbul, Turkey) : Morphometric assessment of active landslides in the higher Himalayan crystallines, Satluj valley, Himachal Pradesh (India). Himalayan Geol 2001, 22(2), 99-107.

Morphometric analysis of landslides has been done in many mountainous and high latitude environments, but its utility has not yet been fully explored in the high energy Higher Himalayan terrain. Reports on the results of a pilot study to provide a database of the morphometric indices for landslides in parts of the Satluj Valley in the Himachal Pradesh. Morphometric assessment of five major and active landslides (mainly translational type) in the Satluj river valley of Indian Himalaya has been done. Various morphometric parameters like classification index, dilation index, tenuity index, flowage index, displacement index etc. have been determined as per the technique suggested by Crozier (1973), for morphometric analysis of landslips using field data of these landslides and topographic information. It has been observed that the technique holds good in interpreting slope stability and the potential process group but there is a need to set the limits of the morphometric indices for various processes of slope movement and the degree of instability that are appropriately defined to suit for the Himalayan terrain. The results are supported by similar observations in other parts of the Himalaya by researchers like Tabatabaei (1993), Mehrotra et al. (1994, 1996) and Parkash (1998). The variations in the limits are also expected due to changes in the nature of slope mass, topography, geology and climate of the terrain.

4 illus, 7 tables, 18 ref

001375   Gultekin A H;Suner F;Orgun Y;Kumral M (Geology Dep, Mining Faculty, Istanbul Technical University, 80626, Maslak, Istanbul) : Metallic and non-metallic mineral resources of SE anatolia, Turkey : a review. J Geol Soc India 2003, 62(5), 581-94.

The metallic ore deposits were formed as a result of the evolution of the Eastern Taurus fold belt in the Alpine tectonic system. This belt is mainly constitued of ophiolite and blueschists of the upper Cretaceous-Oligocene age. The ultramafic and mafic members contain large chromite deposits of podiform type and Cyprus-type massive sulphide deposits. The most important example of the massive sulphide deposits is in Ergani, Elazig, as sea-floor pyritic copper sulphides within the ophiolite complexes. The Keban Pb-Zn deposit is another metallic occrrence as vein an cavity fillings in breccias, and stockworks in the pneumatolytic-hydrothermal stage of the intermediate and acidic magmas indicating a backarc environment. Replacement of the country rocks by high-temperature hydrothermal solution has also resulted in some non-metallic ore bodies empleced especially within limestones, the main examples of which are the phosphate and asphaltite occurrences at Mazidag and Sirnak respectively, ranging in the stratigraphich scale from Cambrian to Quaternary. These formations are metamorphosed to gneiss, schist, phylitte, and marble in the greenschist or amphibolite facies in many places. The main economic occurrences of metamorphic massifs are apatite-rich iron deposits and several epithermal/mesothermal veins along the main faults.

^iia11 illus, 36 ref

001374   Das P K;Singha J C;Sharma A (Geological Sciences Dep, Guwahati University, Guwahati-781 014) : Stratigraphy and sedimentation of the lower tertiary sediments around Sonapur - Lumshnong area, Jaintia hills, Meghalaya, India. Himalayan Geol 2001, 22(2), 55-60.

Two groups are recognised in the present area, viz. the Jaintia and Barail Groups. An attempt is made to differentiate the different formations and members with the help of field and laboratory investigations. The contacts of all the formations of the two Groups recognised in the study area are gradational and conformable. In the study area, the Jaintia Group (Eocene) is divisible into two Formations, viz. Shella and Kopili Formations. The Shella Formation comprises limestone and sandstone members. The lowermost standmost sandstone member is known as Therria Sandstone and the other members of the Shella Formation are Lakadong Limestone. Lakadong Sandstone, Umlatdh Limestone, Narpuh Sandstone and Prang Limestone. The Kopili Formation (Late Eocene) of Jaintia Group comprises alternating layers of thick shales and thin sandstones. The Barail Group (Oligocene) in the study are is characterised by predominant arenaceous sediments (sandstone) with a little development of carbonaceous facies. The sedimentation history of Meghalaya Shelf is influenced by the `Brahmaputra Arch' which acted as barrier for Eocene seas which transgressed both from north and south resulting in the deposition of Shella Formation in the Shelf area. The Kopili represents the regressive deposits subsequent to the major transgressive episode of Shella Formation. The black to dark grey shales with fossiliferous marls with presence of gauconite in the minor sandstones of Kopilis are suggestive of lagoonal enviroment. The change from Kopili sedimentation to Barails is marked by increase in the proportion of coarser clastics.

1 illus, 2 tables, 16 ref

001373   Das A K;Bhaumik P;Bisht S S;Agarwal B (Basin Studies Div, KDMIPE, ONGC, Dehra Dun-248 195) : Seismic mapping of photogeomorphic anomalies observed in the area between Hamirpur and Sundernagar, Himachal Pradesh, Himalayan foothills with an emphasis on hydrocarbon prospectivity. Himalayan Geol 2001, 22(2), 61-82.

A number of geomorphic anomalies of varying shapes and sizes were identified in Kangra-Lambargraon area, H.P. by Remote Sensing Lab. of KDMIPE on the basis of drainage, tonal, and textural pattern from satellite images. All these anomalies lie within the inner tectonic belt between Jawalamukhi Thrust to the west and Main Boundary Thrust to the east. Four such anomalous features fall within Hamirpur-Sundernagar area, marked as `A', `B', `C' and `D'. Makes an integrated approach with an aim to investigate the extension and behaviour of these anomalies in the subsurface. With the help of seismics, well data and surface geological informations, time structure maps on four seismo-stratigraphic levels (Tops of Pre-Tertiary, Subathu, Lower Dharmsala and Upper Dharmsala Formations) have been prepared. All the anomalies are represented either by a `high' trend in almost all the levels mapped although there is considerable shift in their positions. The Hamirpur structural `high', close to geomorphic anomaly `A' is also manifested in the gravity and magnetic anomaly maps. The structural trend in the area, as deciphered from the gravity-magnetic data and time structural mapping, swings from NW-SE to N-S, then to NE-SW as one moves from west to east. The Changartalai structural feature, encased in the subsurface in the traingle zone between Barsar Back-thrust and Kallar Thrust, has probable exploration play in Paleogene section which could not be fully assessed in the well `X'.

15 illus, 11 ref

001372   Chandra S;Joshi S C (NO, G.B. Pant Institute of Himalayan Environment and Development, Garhwal, Srinagar-246 174 (Garhwal)) : Diurnal and seasonal variation in CO₂ levels in the surface air of Garhwal Himalaya. Indian J For 2002, 25(1-2), 205-8.

Systematic measurements of atmospheric CO₂ in the surface air of the study site during the period from February 1996 to January 1997 showed seasonal and diurnal variability in the atmospheric CO₂ concentration, with highest values in the morning and lowest values in the afternoon. The data also showed a winter-summer oscillation in CO₂ levels with a minimum in July - August and a maximum in March. These diurnal and seasonal fluctuations may be related to the photosynthetic activity of vegetation of this region.

3 illus, 17 ref

001371   Cameron D W (Anatomy & Histology Dep, University of Sydney, NSW Australia 2006) : Taxonomic status of the Siwalik late miocene hominid Indopithecus (=Gigantopithecus). Himalayan Geol 2001, 22(2), 29-34.

Re-examines the taxonomic status of the Siwalik hominid traditionally allocated to `Gigantopithecus'. It is argued here that this hominid should be reallocated to Indopithecus Pilgrim, 1915. This conclusion is based on differential patterns of mandibular and dental morphology observed between these taxa. It is also suggested that any similarities between these taxa is a result of functional convergence. They are sufficiently different in their morphology and by inference their modes of mastication to be considered generically distinct. The phylogenetic significance of these hominids remains obscure as mandibular form is largely the result of function, rather than phylogenetic history.

1 illus, 1 table, 27 ref

001370   Bhattacharya D K;Barla V C (Postgraduate Dep of Geology, Ranchi College, Ranchi-834 008) : Geology and preliminary commercial evaluation of the granite deposits in parts of Daltonganj, Palamau district, Jharkhand. Indian Mineralogist 2003, 37(2), 31-8.

Commercial granite occur in several parts of Indian Shield and are distributed throughout the Precambrian terrain. There are nearly thirty potential localities around Daltonganj where varieties of commercial granites occur which have multipurpose use due to their ability to take good polish and other physico-mechanical characteristics. Deals with petrography, physico-mechanical characteristics and commercial evaluation of various types of granites occurring in the area.

1 illus, 3 tables, 12 ref

001369   Bezbaruah D;Kotoky P;Baruah J;Sarma J N (Regional Research Laboratory, , Jorhat-785 006) : Geomorphological explanation of swamps along the Brahmaputra river channel, Assam. J Geol Soc India 2003, 62(5), 605-13.

Wetlands are conspicuous features of the flood plains along the Brahmaputra River, Assam. The sequential change in numbers and areas of wetlands (Bils) for a strtetch of 260 km have been studied using available topographic maps of the Survey of India (1914, 1975) and Indian Remote Sensing satellite imagery (1998). The total number of swamps as evident from the study was 529 in 1914, 783 in 1975 and 781 in 1998. Moreover, total areas covered by the wetlands as observed was 93.73 km² in 1914, 161.23 km² in 1975 and 182.73 Km² in 1998. The low lying nature of the basin, shifting of river channels in a relatively short span of time, associate tectonics of the region and allogenic processes in relation to flood control measures adopted have played a major role in extensive changes to the wetlands over this period. The data presented here aid in formulating an effective flood control stratey to be adopted for this perennial flood prone area, stabilisation of landforms and different wetland management approaches.

5 illus, 13 ref

001368   Basavaraju M H;Pundeer B S (Regional Geological Labs, ONGC Ltd., Sivasagar-785 640) : Occurrence of early permiuan palynofossils in the subsurface sediments of Dhansiri valley, Assam-Arakan basin, India. J Geol Soc India 2003, 62(5), 627-33.

The occurrence of Lower Gondwana palynoassemblage has been recorded from the subsurface sediments of an exploratory well Dergaon-A in Dhansiri Valley of Assam-Arakan Basin. The recorded palynoassemblage includes rice radial monosaccate genera Potoneisporites sp, Parasaccites sp, Plicatipollenites sp, Virkkipollenites sp, associated with the trilete spores viz. Microfoveolatispora sp, Microbaculispora sp, along with acritarch Leiosphaeridia sp. These palynofossils are correlatable with those recorded from the Talchir Formation of South Rewa Basin, Jayantia coal field, Cauvery Basin and Krishna Godavari Basin. Occurrence of Leiosphaeridia indicate that the sediments appears to be deposited under marine conditions.

2 illus, 1 table, 13 ref

001367   Baruah P K (Applied Geology Dep, Dibrugarh University, Dibrugarh-786 004) : Sandstone composition and tectono-provenance of Dafla and Subansiri formations from Kinin-Zero road-section of Arunachal Pradesh. Himalayan Geol 2001, 22(2), 41-54.

Petrographic study reveals that the major detrital framework grains comprise of non-undulatory, undulatory and polycrystalline quartz, mica, feldspar such as plagioclase, microcline, orthoclase, perthite and, sedimentary and meta-sedimentary lithics. The QFL and LmLvLs ratios for Dafla and Subansiri formations have been counted as Q_56±6.6 F_3±0.7 L_41±6.7 and Lm_72±4 Lv_5±2.5 Ls_23±5, and Q_43±7: F_2±1 L_55±7 and Lm_86±4 Lv_4±3 Ls_10±6 respectively in which the Subansiri for its higher count of medium-/higher grade metamorphic lithics and Dafla with higher value of low-grade metamorphic lithics, the mean Ls (sedimentary)-Lm1 (low-grade)-Lm2 (Medium/higher-grade) ratio lies as Ls_25±5 Lm1_45±3 Lm2_30±2 and Ls_11±6 Ml1_35±3 Lm2_54±4. The sandstones mostly comprise of argillaceous matrix and cements. Diagenesis is not intense in the rocks however, evidence is supported by corrosion of grain margin, quartz overgrowth, authigenic mica, secondary development of chert and dissolution of feldspar. Moderately to ill-sorted sediments of Dafla and Subansiri formations were the product of recycled orogen provenance that mostly comprise of igneous and metamorphic terrain and subordinately sedimentary sources. The sediments under semi-humid climatic condition transported along moderate to steep gradient relief might have been deposited in low to moderate energy dominated environments.

8 illus, 3 tables, 28 ref

001366   Armas I;Miu S (NO, , Str. Vitorului 197, Bl. 42B, sc.l, et.3 at. 9, sect. 2 70239 Bucharest, Romania) : Non-linear multiple regression model of various-order basin areas; example from Doftana basin, Romania. Himalayan Geol 2001, 22(2), 35-40.

Models have been expressed in the form of direct or inverse geometrical progression, on univariate basis. The aim of study is to offer a multivariate mathematical model capable of expressing the interrelation between the various-order basin areas and the characteristics of the major variables (mean stream vertical distances, number of stream segments and the mean basin slopes) determining them. Because of its versatile nature, the non-linear multiple regression law can describe very effectively the relationship between area and internal parameters of any basin, under any geomorphological regime.

3 illus, 3 tables, 7 ref

000231   Yano T;Matsumoto Y;Wu G (Faculty of Education and Regional sciences, Tottori University, Tottori-680 8551, Japan) : Pacific genesis induced from phanerozoic reheating of upper mantle. Himalayan Geol 2001, 22(1), 51-64.

The late Mesozoic two giant events that have synchronously occurred in the Pacific and periphery are the tectonomagmatic activities of the circum-Pacific mobile belt and the Darwin Rise. Their dynamics analysis indicates that the geodynamics responsible for Pacific genesis has been driven by the gravity instability between a Pacific-wide superplume head and its lithospheric overburden under the influence of eastward asthenospheric flow by the Earth spin. The worldwide activation of mafic magmatism since the Paleozoic climaxed around the Jurassic. The separated not worldwide distribution of the magmatism on the Earth suggests the inhomogeneous reheating of upper mantle, as represented by the Pacific-wide plume head. The resultant inhomogeneous contraction produced the hypsographic bimodality of the solid Earth surface through some oceanization mechanism.

7 illus, 62 ref

000230   Vogel K (NO, , Gabelsbergerstr 27, 08412, Werdau, Germany) : New view to the coastal types of Alfred Wegener. Himalayan Geol 2001, 22(1), 91-2.

^ssc1 illus, 2 ref

000229   Vijay Kumar (NO, National Institute of Hydrology, Western Himalayan Regional Centre, Satwari, Jammu Cantt-180 003) : Rainfall characteristics of Shimla district (H.P.). J Indian Wat Resour Soc 2003, 23(1), 1-10.

The study presents the analysis of monthly, seasonal and annual rainfall in the Shimla district of Himachal Pradesh. The statistical parameters like mean, standard deviation, coefficient of variation and coefficient of skewness of the rainfall in the district were determined. Rainfall data, observed by the India Meteorological Department (IMD), available in varying length from 15 to 27 years (starting from 1965) at 16 different stations in the district is used in the analysis. Mean annual rainfall is found to be maximum at Phancha (2086mm) and minimum at Kumarsain (556mm). The coefficient of variation of annual rainfall varies from 17% to 50%. The annual rainfall is found to be non-symmetrically distributed at all statiosn. Time series of annual rainfall at various stations were examined for trends using the Kendall rank-correlation statistics and regression analysis; and for persistence using the auto-correlation analysis. Results indicate that annual rainfall in the district is by-and-large stable. The annual rainfall series is found to be random at most of the stations, except at Shillaru, where Markov linea type persistence is observed. Arithmetic, thiessen polygon and isohyetal methods were used to calculate the average depth of rainfall over the district, and it was found to be 1073 mm, 10767 mm and 1106mm, respectively.

6 illus, 7 tables, 18 ref

000228   Tsunoda F (Saitama University, , 255 Shimo-Okubo, Urawa, Saitama Prefecture-350 1141, Japan) : Middle pleistocene uplife of the south fossa magna region. Himalayan Geol 2001, 22(1), 17-25.

In the Japanese Islands the initial structures are barely preserved in the older orogenic belts, but are fairly distinct in the younger ones. The cental part of this island arc was uplifted with the Miocene granite masses and andesite dike swarms. These crustal movements which began at the end of the Miocene epoch are still working at present and resulted in the north-woth trending anticlinal zone of the South Fossa Magna Region. The so-called Pleistocene subducted micro plates could not be found in this upwarped tectonic area.

8 illus, 15 ref

000227   Tassos S T (Institute of Geodynamics, National Observatory of Athens, P O Box-200 48, 118 10 Athens, Greece) : Excess mass stress tectonics (EMST) : an outline of the hypothesis. Himalayan Geol 2001, 22(1), 117-32.

Geodynamic phenomena are attributed to Excess Mass Stress (EMS). The basic idea is that the Earth expands and not due to a heat but to a stress engine. Below the depth of about 100 km in Earth's interior, electromagnetic and nuclear forces, not heat and gravity, are considered to dominate. Excess Mass (EM) is the product of transformation of cold plasma (electrons, protons and positive ions) into bulk matter, within the outer core, through electromagnetic confinement, resonance, laser clustering, shockwaves, and controlled nuclear fusions. About 3.6 x 10⁵¹ nucleons, most of them as ²H nuclei, a small number of free protons and about 10⁵³ electrons were trapped inside the primordial Earth. The primordial Earth had a diameter about 40% its present size. Up until now about 2/3 of this original number of ²H nuclei have been transformed into bulk matter in two distinct phases: The first from 4000-200 m.y.a., when a granitic continental type crust, with a thickness of 300-350 km, was fored. In the second phase (200 m.y.a. to present ), the Fe-rich oceanic crust and more than 90% of the rigid mantle were formed. During orogenic episodes, caused by an intensification of laser clustering, degeneracy pressure is reduced and the Earth tends to contract. The net result of its electrical unbalance is pulsation of the Earth (Expansion-contration), which is superimposed upon its general expansion due to EM generation and emplacement processes.

4 illus, 3 tables, 31 ref

000226   Swami Saran;Gupta R P (Civil Engng Department, Roorkee I.I.T., Roorkee-247 667) : Seismic earth pressures behind retaining walls. Indian Geotech J 2003, 33(3), 195-213.

Dimensionless parameters are derived for the analysis of active earth pressures against retaining walls on the assumption of plane surface of failure under earthquake condition. Walls having inclined face with inclined backfill carrying uniform surcharge have been considered. Both horizontal and vertical accelerations due to earthquake have been incorporate in terms of seismic coefficients. An allowance for tension cracks has also been made.

8 illus, 2 table, 7 ref

000225   Suzuki Y (Geothermal Energy Research and Development Co. Ltd, , Kyodo Bldg. 11-7, Kabuto-cho, Nihonbashi, Chuo-ku, Tokyo-103-0026, Japan) : A proposal of three dimensional geotectonics. Himalayan Geol 2001, 22(1), 27-32.

The island arc tectonic system composed of trenches, island arcs, marginal seas, inland basins and their neightbouring upheaving regions is defined and the geologic development shows that the deep earthquake zone is resulted from the concentration of stress and strain due to upheaval of the system and subsidence of the neighbouring oceans. Tectonic movements similar in mode and different in scale observed on the surface of the earth must be derived from the depth difference of driving and are inconsitent with the convection current hypothesis. Mantle tomography suggests the future three dimensional geotectonics.

10 illus, 14 ref

000224   Sun Yoon (Department of Geology, Busan National University, Busan-609 735 Korea) : Tectonic history of the Japan sea region and its implications for the formation of the Japan sea. Himalayan Geol 2001, 22(1), 153-84.

The Japan Sea, a marginal sea of the Northwestern Pacific, is bordered by regions with a continental crust of various ages. The general topographic features of the Japan Sea are the polygonal peripheral shape in plan view (Japan Sea Polygon) and the deep depression in the northeastern half and the irregular topography in the southwestern half which comprises high ridges and deep troughs. Four round depressions are recognised in the Japan Sea Polygon: East Japan Basin Depression, West Japan Basin Depression, South Ulleung Depression and South Yamato Depression. Three stages in the formation of the Japan Sea are recognised: Stage I: Multi-graben seaway (58? or 36.5-18 Ma); Stage II: Broadly-open Paleo-Japan Sea (18-7 Ma); Stage III: Polygonal Japan Sea (7 Ma-Present). The tectonic history of the Japan Sea suggests that the Japan Sea was formed by block faulting and collapse of the continental crust, caused by uprising magma. That is, the origin of the Japan Sea is not through horizontal spreading but, rather, vertical movement. Surge tectonics is the probable hypothesis for the formation of the Japan Sea, and the Japan Sea region seems to be an upwelling and swelling segment of the northwestern Pacific active margin surge channel. Of the four round depressions in the Japan Sea, The East Japan Basin and West Japan Basin depressins seem to be vortex structures, and the South Ulleung and South Yamato depressions seem to be channel overlaps in the segment.

15 illus, 130 ref

000223   Strutinski C;Puste A (Geological Institute of Romania, , Cluj Branch; POB-181; RO-3400 Cluj 1/Romania) : Along-Strike shearing instead of orthogonal compression : A different viewpoint on orogeny and regional metamorphism. Himalayan Geol 2001, 22(1), 191-8.

Orogeny has been regarded for over a century as a compressional phenomenon due either to contraction or to lithospheric collision. However, generation of linear structures like orogens can hardly be explained by variation over large areas of stress gradients, as is to be expected in the rigid-plate convergence assumption. Lateral escape - implied by newer plate-tectonics interpretations to overcome this difficulty - might apply to some degree, but should by no means be more important than up and outward escape, i.e., in the direction of minimum principal stress. Movement indicators in regional metamorphic rocks have shown that tectonic transport along the orogens is a matter beyond question but also that this transport be gives at a very early stage, a situation that contradicts the lateral escape model. Therefore, it has been assumed that the lateral movement is not due to compression, but to transcurrency, which has both the maximum and minimum principal stresses in the horizontal plane. This agrees particularly well with the observed belt-like distribution of deformation. Two models are advanced, the corridor and the gliding-blocks model, which are not mutually exclusive, even if each of them relates to a specific geotectonic setting.

6 illus, 33 ref

000222   Sivakumar Babu G L;Satyanarayana Murthy D (Civil Engineering Dep, Indian Institute of Science, Bangalore-560 012) : Reliability based seismic stability of soil slopes. Indian Geotech J 2003, 33(3), 233-47.

A probabilistic stability analysis is carried out for slopes in seismically active zones, taking into consideration inherent uncertainties assoiated with the soil parameters. The effect of correlation between the stength parameters on the stability is studied. Safety in terms of reliability index, defining satisfactory performance is evaluated for various combinations of input parameters. The total expected cost of slope is evaluated for each set of data taking into account the initial cost, consequence cost and associated probability of failure. It has been shown that it is possible to obtain balanced or optimum sections considering uncertainty in soil parameters in the form of reliability index, consequence costs for a given horizontal seismic coefficient. The methodology used is useful to choose slope geometry within an economic framework, satisfying the requirements of safety, economy and uncertainties involved.

3 illus, 4 tables, 21 ref

000221   Sharma R;Verma P;Sachan H K (Wadia Institute of Himalayan Geology, , Dehra Dun-248 001) : Strontium isotopic constraints for the origin of barite mineralization of Tons valley, Lesser Himalaya. Curr Sci 2003, 85(5), 653-6.

Veins, pockets and lenticles of barite are found to be associated with Neo-Proterozoic Nagthat Formation in Tons valley. The relation of barite mineralization with the siliciclastic host rocks and its depositional characters favour a stratabound syngenetic origin for barite. However, late event of remobilization partly obliterates the primary features. The strontium isotope ratios of barite have been are presented and the data have been used to understand the source and origin of barite. The obtained ⁸⁷Sr/86Sr ratios range from 0.720448±0.000034 to 0.728637±0.000039; these values rule out the possibility of involvement of mantle/magmatic source in the deposition of the Lesser Himalayan barite. Isotopic data reveal that strontium in barite is derived from the crustal source rocks and the local process like recrystallization has influenced this barite mineralization.

3 illus, 2 tables, 22 ref

000220   Ramasamy G;Kaushik N P (Civil Engineering Dep, Indian Institute of Technology Roorkee, Roorkee-247 667) : Effect of choesive fines on performance of compacted sand fills. Indian Geotech J 2003, 33(3), 264-78.

River sand, often used as fill material, is mostly poorly graded and therefore not amenable to high degree of compaction. Addition of clayey fines to sand is known to improve the degree of compaction. However, knowledge based on the quantum of improvement with respect to load-settlement behaviour of compacted fills made of mixture of sand and cohesive fines and the optimum amount of fines to achieve the best results. Results of a comprehensive study consisting of load-tests and tests for engineering properties on compacted soil mixes of sand and cohesive fines have been presented. The study shows that compacted beds prepared by addition of about 5 to 10% of conhesive fines to sand, perform much better with respect to bearing capacity and settlement as compared to bed of sand alone. The studies also show that the optimum amount of cohesive fines is the one which when added and compacted at optimum moisture content (OMC) results in a void ratio equal to that of the sand at its densest state.

7 illus, 2 tables, 17 ref

000219   Parubets N (Granton Institute of Technology, , 263 Adelaide Street West, Toronto, Ontario, M5H 1Y3, Canada) : The new concept of the origin of continents. Himalayan Geol 2001, 22(1), 185-90.

Combining the ideas of W. Hartmann, D. Davis, E. Shoemaker and other astronomers, particularly the conclusions flowering from their exploratory calculations using accretionary theory, with an analysis of the established facts relating to the Permian/Triassic boundary, yields a new perspective on the Earth's tectonic evolution, one that helps resolve the contradiction between: the vertical movements and the now almost universally recognized horizontal crustal mobility, the drift theory and the expansion hypothesis, and the `mobilistic' and `fixist' concepts. Additionally, this provides a possibility of finding satisfactory answers to many of the still unresolved fundamental questions of geodynamics, including the numerous geological paradoxes.

25 ref

000218   Menon R;Senthil Kumar P;Koti Reddy G; Srinivasan R (National Geophysical Research Institute, , Uppal Road, Hyderabad-500 007) : Radiogenic heat production of late Archaean Bundelkhand granite and some proterozoic gneisses and granitoids of central India. Curr Sci 2003, 85(5), 634-8.

Abundances of heat-producing elements, K, U and Th, in some of the granites and gneisses of the Bundelkhand and Bastar terrains have been estimated by in situ gamma-ray spectrometry. The Bundelkhand granite is an I-type, calc-alkaline granite complex made up of porphyritic, coarse-to-medium grained and fine-grained granites. It caries macro enclaves of <126> 3.5 Ga-old tonalitic gneisses. These gneisses have a low heat production of 1.4μWm^-3. The mean heat production of the dominant porphyritic and medium-to-coarse grained Bundelkhand granite is 5.5 μWm^-3. The heat production of the Proterozoic Jabalpur granite intruding the Mahakhosal greenstone belt is 3.4 μWm^-3. The Tirodi gneisses resulting from migmatization of psammopelites of the Sausar Group, are characterized by a mean heat production of 3.8 μWm^-3. The cataclastic biotite gneisses of the Tattapani geothermal area are the highest heat-producing rocks encountered in the Bundelkhand terrain with a mean heat production of 7.4 μWm^-3. The tonalitic Amgaon gneisses of the Bastar terrain are characterized by a heat production of 0.7 μWm^-3, which is about half of the mean heat production of the tonalitic gneisses occurring as inclusions in the Bundelkhand granite. Mean heat production of the Proterozoic Amgaon and Dongargarh granites are 2.5 and 2.9 μWm^-3, respectively.

1 illus, 2 tables, 36 ref

000217   Meenakshi P;Saseetharan M K (Civil Engineering Dep, Coimbatore Institute of Technology, Coimbatore - 641 014) : Analysis of seasonal variation of suspended particulate matter and oxides of nitrogen with reference to wind direction in Coimbatore city. J Instn Engrs-Pt EN 2003, 84(Sep), 1-5.

Pollution Rose Diagrams are the two-way joint frequency distribution between wind direction and pollution concentraton. The data of pollutant concentration, frequency of occurrence of a specific range in a particular wind direction are the basic requirements for air quality management programme. The data in the form of pollution rose can be easily interpreted and effectively analysed. Five-air quality monitoring stations, namely, Peelamedu, Ganapathy, Gandhipuram, Gandhi Park and Ukkadam are selected based on the anthropogenic activities. The suspended particulate matter and oxides of nitrogen concentrations have been monitored every seventh day of each of the monitoring stations. The wind direction is monitored once in an hour on the day of monitoring the air pollutants. From this, the prevailing wind direction is chosen as the direction in which maximum frequency of occurrence of wind flow has taken place. A computer program has been developed in `C' language and is used to generate the frequency table by getting the pollutant concentration and the prevailing wind direction on the monitoring day as input. The frequency table so generated is converted into a pollution rose. The pollution roses are drawn for each station for four reasons.

3 illus, 2 tables, 9 ref

000216   Maxlow J (NO, , Terrella Consultants, 29 Cecil St., Glen Forrest, Western Australia, 6071) : Earth expansion : Quantification using oceanic magnetic isochron mapping. Himalayan Geol 2001, 22(1), 103-16.

Earth's asymmetric expansion is now measureable, and spherical modelling achievable, using modern oceanic magnetic isochron mapping and continental geology. The oceanic magnetic isochron and continental geological mapping, shown in the Geological Map of the World (CGMW and UNESCO, 1990), was used in this study to latitudinally and longitudinally constrain plate configuration, and mathematically derive a rate of Earth expansion, from the Archaean to Recent. Magnetic isochron mapping is ideally suited for post-Jurassic quantification of palaeoradius and plate reconstructions on an Earth undergoing exponential expansion, and demonstrates a significant fit-together of all plates for each time interval. The utilized oceanic data set is further substantiated by current research incorporating palaeomagnetic palaeopole determinations. These data delineate diametrically opposed palaeomagnetic pole clusters for each era back to the Archaean, without need to consider an `apparent polar wander'. The palaeopole data is supported by palaeogeographic, palaeobiogeographic, and palaeoclimatic indicators, which define a palaeoequator consistent with palaeomagnetic determinations. Furthermore, biogenic distributions demonstrate a spatial and temporal clustering, reducing the need for excessive migration routes or incongruous provincial distribution. This geologic and geophysic data collectively suggest that all continental plates, inclusive of cratonic and intracratonic basins, have retained their spatial integrity throughout geologic history.

9 illus, 41 ref

000215   Maurya D M;Thakkar M G;Chamyal L S (Dep of Geology, M S University of Baroda, Vadodara-390 002) : Implications of transverse fault system on tectonic evolution of mainland Kachchh, western India. Curr Sci 2003, 85(5), 661-7.

The tectonic evolution and seismic phenomenon of Kachchh region have been attributed to differential movement along the E-W trending master faults. However, a NW-SE to NE-SW transverse fault system also exists which cuts across the E-W tectonic fabric of Kachchh. The study attempts to delineate the role of transverse faults in pre-Quaternary and Quaternary tectonic evolution of Mainland Kachchh based on a regional scale geomorphic study. Significance of these transverse faults in the tectonic evolution of Kachchh is obvious as they laterally displace the large E-W faults and the domal structures associated with tehem. The Kachchh Mainland Fault (KMF) and the Katrol Hill Fault (KHF) are the two major E-W trending master faults of Mainland Kachchh which show distinct offsets along transverse faults. Geomorphic evidences of strike slip movement along the transverse faults affecting the KMF and KHF are seen in the form of displacement of major fault scarps, beheaded/deflected or offset drainage, sags, shutter ridges and pressure ridges. The observed amount of offset along the transverse faults ranges from a few hundreds of metres to several kilometers, which includes a pre-Quaternary as well as a Quaternary component. It is suggested that a part of the stresses being accumulated on the E-W trending faults is being possibly transmitted to the NW-SE to NE-SW transverse faults, which may account for the present seismic phenomenon in Kachchh.

4 illus, 22 ref

000214   Leybourne B A;Smoot N C (NAVOCEANO, Geophysics Division, Stennis Space Center, MS-39522, USA) : Surge hypothesis implies gravitational teleconnection of tectonics to climate : El nino and the central pacific geostream/jetstream. Himalayan Geol 2001, 22(1), 139-51.

Based on surge tectonic concepts, the coupling of tectonic dynamics with ocean/atmosphere dynamics is explained. This is confirmed experimentally uses the following assumptions: Oscillations or taphrogenesis/tectogenesis (expansion/contraction) of the earth generates tectonic fronts that migrate slowly eastward across oceanic basins. Earth rotation is conducive to eastward migration of tectonic frontal boundaries, which reconfigure tectonic pressure cells or vortices. This tectonic reconfiguration alters existing atmospheric pressure patterns, thus altering jetstream configurations controlling climate trends. In addition, the geodynamo has an intertropical convergence zone. The upper-level flow structure of this intertropical convergence zone is reflected in the tectonic trends across basins along the equator. Tectonic pressure fluctuations are transferred across the oceanic basin via major geostreams of the tectonic intertropical convergence zone, thus explaining the El Nino Southern Oscillation teleconnection. Tectonic fronts produce changes in tectonic flow rates and direction along tectonic trends with enough mass to produce fluctuations in the gravitational field. These regional fluctuations in the gravitational field affect local atmospheric pressure through density or phase changes of mineral suites within tectonic eddy or vortex structures. These structures are associated with island arcs and offsets along mid-ocean ridges, rift zones and maintain fold belts.

8 illus, 76 ref

000213   Kobayashi K et al (Nagano-nishi High School, , 3-8-5 Hakoshimizu Nagano, 380-8530 Japan) : On the recent pulsating crustal movement in northeast Honshu, Japan. Himalayan Geol 2001, 22(1), 133-8.

The first order triangulation stations set at an interval of 40 or 50 km in Central and Northeast Honshu were surveyed around 1895, 1958 and 1979 by the Military Land Survey before World War II and the Geographical Survey Institute after the war. The authors apply the strain analysis method by Terada and Miyabe (1929) to those data. The recent crustal movements are not unilateral, but are reversed, namely dialated and contracted areas in a period turn to the opposite ones in the next period, respectively. Most of destructive earthquakes occur in the areas larger than 10^-5 maximum shear due to the elastic limit of strain of rocks, and support the earthquake volume hypothesis by Tsuboi (1967). The principal strain axes are not always definite, but changeable, and wide areas are found, where both principal axes show contraction or dilation. The fact must be due to the result of contraction or expansion under those areas, contradicted to the horizontal compression due to the plate motion as supposed by the plate tectonics.

5 illus, 7 ref

000212   Jayangondaperumal R;Dubey A K;Sangode S J; Sathyanarayana K V V (Wadia Institute of Himalayan Geology, , Dehra Dun-248 001) : Superimposed folding, finite strain and magnetic lineation in the Mussoorie Syncline, lesser Himalaya: implications for regional thrusting and the Indian Plate motion. Himalayan Geol 2001, 22(1), 207-16.

Field, finite strain, and anisotropy of magnetic susceptibility (AMS) studies were performed in the Mussoorie Syncline, Garhwal Lesser Himalaya. Random orientation and low axial ratios of strain ellipses, even in the vicinity of the Main Boundary Thrust (MBT) and the klippe detachment thrust, indicate an overall weak deformation and low magnitude of simple shear along the thrusts. The orientations of the strain ellipses and associated magnetic lineations are controlled by the early and superposed fold hinge lines. The study, in concurrence with most of the earlier field based investigations, highlights the importance of folding and emphasizes its dominant role in the development of stretching mineral lineation. It is inferred that the relationship between stretching mineral lineation and Indian plate motion is one of the several over simplifications incorporated in the theory of plate tectonics.

4 illus, 1 table, 55 ref

000211   Hayakawa M (NO, , Furuichiba 1-53, Saiwai-ku, Kawasaki-shi, Kanagawa-ken-212-0052, Japan) : Seismicity and volcanic activity in Japan. Himalayan Geol 2001, 22(1), 33-9.

When one considers the mechanism of earthquake occurrence, besides the factors of stress, fissure formation and water penetration, there must be another important element to be considered, that is the existence of heat. In the great inter-plate earthquakes of Japan with Hypocenter depth of 30-40 km, the subduction of the Pacific plate will act to drag down the margins of the main Japanese islands as part of the overlying plate. These great earthquakes are said to occur in the low heat flow zones. However, after careful investigations, it is clear that the great earthquakes have not always taken place only in the low heat flow zones, namely some of them took place in comparatively high heat flow zones of 2.0 HFU or more, such as the sea just south off the southweastern Japan. It is obvious from the thermal gradient curves in such high heat flow zones that temperature at the hypocentral depths approaches the melting point of wet peridotite. Under such circumstances, the partial melting proceeds by the effect of some pressure decrease or temperature increase associated with the huge tectonic force acting on the rocks. The partial melting will yield some increase in volume, resulting in the additional to the tectonic force triggering earthquakes. Based on the upward energy movement from the depths in the earth's crust, the seismicity including volcanic activity has been reconsidered for the last 400 years in and adjacent Japan, and some interesting results have been obtained.

6 illus, 1 table, 9 ref

000210   Fujita Y;Kubota Y;Yamauchi S;Adachi H; Takegoshi S (NO, , 6-19-8, Nagao, Tama-ku, Kawasaki-214 0023 Japan) : Magmatic and tectonic activities characterizing the green-tuff disturbance. Himalayan Geol 2001, 22(1), 93-101.

The late Oligocene to Quaternary tectonic movements called the green-tuff disturbance occured on the marginal sea side of the Japanese island arcs, forming the structural framework of the present archipelago. Most important factors of the disturbance are the genesis of collapse basins and subsequent magmatism due to the squeezing of a large amount of magma from the mantle into the crust. Such a type of collapse basin, named Motojuku Collapse Basin (MCB), is less than 20 km across and polygonal-shaped in plan view, and numerous MCBs have appeared at six stages of magmatic activation during the disturbance. A crowded distribution of MCBs is designated a Swarm of MCBs (a SMCB), whose major axes are parallel consistently with the general trends of the islands arcs. The SMCBs formed through the six stages compose the five Volcano-Tectonic Zones (VTZs) arranged in the general trends of the island arcs. Thus it is concluded that the VTZs were underlain by a great number of magma chambers disposed in the general trends of the island arcs. It is also suggested that a huge subsiding zone up to 6,000 m deep within the VTZs of the Northeast Japan arc, the Tokoku Belt, holds some tectonic meaning for the genesis of island acrs and marginal seas.

6 illus, 20 ref

000209   Dickins J M;Choi D R (Innovative Geology, , 14 Bent St., Turner, A.C.T., 2612, Australia) : Neogene events and the modern world. Himalayan Geol 2001, 22(1), 199-206.

Before the Neogene much land and/or shallow sea was to be found in the present oceans and the deep trenches. The continental rift systems were strongly developed and took on their contemporary shape. From this time, the Alpine-Himalayan and Circum-Pacific mountain chains gained their existing higher relief and there is a marked change in tectonic direction dating from this time. These changes are reflected in plate tectonic explanations by a change in ocean spreading directions. The Neogene is also marked by a period of strong widespread basic magmatic activity associated with the continental rift systems, continental flood basalts and apparently on a large scale in the ocean basin. The changes seem to begin in the uppermost Oligocene. The beginning of the changes is at about 25 Ma but the radiometric scale, in the main, is rather inexact compared with good palaeontological dating. The simplest explanation of the changes is that the earth's overall relief has increased. Much evidence has now accumulated which shows that continental rifts are compressional as also are the oceanic ridges and the `back arc' basins. Therefore, that the bases of the oceanic trenchs bordering the modern geosynclines show a relatively low order of seismic activity and the sediments are generally little disturbed.

5 illus, 55 ref