Annual Report 2000 - 2001

Autonomous Institutions

Astronomy & Astrophysics (AA)

1. Astronomy & Astrophysics:

• The power spectrum of the cold HI gas in the Galaxy was obtained and its implications discussed. The power spectrum is non-Kolmogorov.
  
• Radio source population in one of the high redshift (z~0.5) cluster was analysed for its color, and its projected distribution in the cluster.
  
• The expected temperature anisotropy in the cosmic microwave background radiation due to galactic winds at high redshift was worked out.
  
• The implications of the curious properties of the geometric phase, discovered in earlier work, for the theory of the geometric phase and for problems in other areas of physics are being explored.
  
• Some simple experiments on polarization optics were started.
  
• It was shown that after inclusion of general relativistic effects in the determination of polar cap sizes, the observed core component-width relation for pulsars leads to constraints on the equation of state of neutron stars.
  
• First part of the investigation of leads/lags between core and conal components was completed.
  
• The possibility that the observed extreme scattering events (ESE) are not due to any mysterious discrete concentrations, but rather just the combined manifestation of a whole range of hierarchical scales constituting the distribution of the ionized matter was examined. It was found that a single power-law description of the electron density distribution in the ISM is consistent with the observations.
  
• Scintillation decorrelation bandwidth for the pulsar J0437-4715 at 150 MHz was estimated.
  
• All the available data at various wavelengths for a number of gamma ray burst afterglows are being collected to construct light curves and multiwavelength spectra (from Radio to X-rays) for them.
  
• A dozen giant radio sources were observed using the VLA. The data analysis is complete. The aim of the observations is to study the evolution of giant radio sources, measure the spectral index gradients across the lobes and estimate the spectral ageing in these class of objects.
  
• A sample of bright radio sources to search for the HI absorption in the redshift range 1.1 - 1.4 using the GMRT was made by going through literature in detail.
  
• Reformatting of all the data covering 24 hrs. of LST and development of editing and mapping procedures for the data from the Mauritius Radio Telescope was carried out.
  
• Analysed high resolution recombination line & continuum data at 8.3 GHz from NGC 253
  
• Modelling of recombination lines observed towards the blue compact Dwarf Galaxy NGC 5253 was completed
  
• Upper limits to the line optical depths obtained towards 3C84 were used to derive constraints on the electron density and line widths.
  
• HI observation towards the galaxy NGC 1359 made with the GMRT was analysed.
  
• Modelling of the velocity field in the central region of NGC 253 using a bar potential was completed.
  
• Data was taken with GMRT at 1.05 GHz towards M82, NGC 253 and the Galactic centre to search for recombination lines.

2. Instrumentation for Astronomy:

• Under the ISRO-RRI collaboration on VLBI Experiments, design and development of Instrumentation was carried out for another frequency transfer experiment using INSAT 2A. An improved Low Noise Amplifier operating at 6.7GHz for use on the RRI 10.4 m Telescope & other VLBI nodes was designed. Prime focus feed horns at 6.7 GHz were designed.
  
• Calibration methods for polarization measurements with particular application to GMRT (pulsar) data were developed.
  
• Designed a set of coded mask patterns on the basis of detailed computer simulations and handed them over to ISRO for fabrication of the prototype Coded Mask for the x-ray sky monitor.
  
• Some tests of the system characteristics of the 220 GHz radiometer were carried out at Hanle. Tipping scans were taken to determine the zenith position. A partial analysis of the calibration scans have been completed.
  
• For the wideband Correlator, four IF boards were populated and tested. Design of Multilayer PCB for high speed sampler working at 100 MHz was completed. Design of multilayer PCB for housing four NASA Correlator Chips was taken up.
  
• Several types of wide band feeds were studied for the use in the prototype antenna for the Compact Cluster Telescope (CCT). Two trapezoidal feeds, one covering 0.5 - 6 GHz and the second one covering 1.5 - 9 GHz were built and tested. These feeds were used for an initial measurement of radio frequency interference (RFI) at Gauribidanur.
  
• Spare systems for the GMRT Array Combiner and the Polarimeter were completed. Control and user interface software were modified to incorporate additional features.
  
• Testing of high yield strength of stainless pipes for fabrication of a prototype 12m parabolic dish was completed.
  
• As a part of the ISRO-RRI collaboration, a complete baseband transmission and receiver system has been fully designed and built for high stability frequency transfer via INSAT. This includes generation of four tones based on a common reference, combining and amplifying them suitably to interface with the upconverter available at MCF, Hassan. Similarly, a receiver was designed and built to accept signals from a down-converter and recover the frequency reference at any place within the footprint of INSAT. The system is being integrated and tested.
  
• A PCI-based high speed data acquisition card has been designed and sent for fabrication. This card is aimed at sustaining data throughputs of upto 40 MB/s into the card through both parallel and high speed serial ports.
  
• The antenna, the correlator and the computer systems of the Mauritius Radio Telescope were made fully functional again for further observations.
  

Proposed Research activities for the rest of the year (upto 31.3.2001)

1. Astronomy & Astrophysics:

• Studies of HI absorption in the Warm Neutral Medium will be pursued further towards several directions in the Galaxy.
  
• HI and radio continuum imaging of clusters will be carried out with the purpose to study the gas content and star formation rates of cluster-galaxies and their possible evolution with redshift.
  
• Nature of high random velocity clouds in the Galaxy will be investigated through 21 cm HI observations.
  
• The evolution of entropy of the hot gas in galaxy clusters will be investigated. It has been suggested that the entropy is substantially larger than that is possible from gravitational contraction. It is proposed to study a few possible causes of this discrepancy in detail.
  
• Work on the properties of geometric phase will be continued.
  
• Numerical work will be taken up to investigate leads / lags between core and conal components of pulsars.
  
• Analysis of data previously obtained using the RRI 10.4 m telescope, on monitoring of SiO masers is proposed to be completed as also a statistical study of the characteristics of the SiO maser sources.
  
• Further work will be taken up on emission pattern mapping of a few bright drifting pulsars
  
• A low-frequency pulsar search will be initiated from GBD.
  
• Single-pulse observations on some bright southern pulsars and a survey of fluctuation properties of southern conal pulsars will be taken up with the Parkes telescope in Australia.
  
• A comparison of theoretical predictions of GRB afterglow spectra with what is actually observed will be made.
  
• Studies of the role of ambipolar diffusion in the evolution of crustal neutron star magnetic fields will be undertaken.
  
• A web-based training/familiarisation package on High-Energy Astrophysics to facilitate the participation of a wide community of researchers in this area will be put together.
  
• Observations of giant radio sources using the GMRT and the VLA will be made. GMRT will be used to observe HI absorption at various redshifts.
  
• X-Ray emission from a highly variable X-Ray source Cygnus X-3 will be studied and modeled using the RXTE data .
  
• Interpretation of high resolution Recombination line and continuum data on NCG 253 will be carried out.
  
• Modeling of ionized gases in the starburst galaxies NGC 4945, circinus, He 2-10, NGC 1808, and NGC 5253 will be carried out.
  
• HI absorption towards HII regions observed with the GMRT will be analysed and interpreted.
  
• OH absorption detected towards the elliptical Galaxy NGC 1052 will be interpreted.
  
• Further observations of the Galactic centre with the GMRT will be carried out.
  
• Observations of HI emission from nearby galaxies using the GMRT will be taken up.
  
• As part a of the space astrometry collaborative program between ISRO and RRI, it is proposed to conduct the first trials of a VLBI experiment between Hassan and Bangalore using the INSAT satellite for frequency transfer and observing a few strong methanol masers at 6.7 GHz.
  
• Data from the Mauritius Radio Telescope will be analysed to obtain full resolution images of the entire LST range at southern declinations.
  
• Under the ISRO-RRI collaboration for VLBI Experiments, some experiments will be conducted at MCF, Hassan and preparation will be made for satellite receivers using the new 3m Offset Paraboloid. VLBI Observations will be attempted between Hassan & Bangalore.

2. Instrumentation for Astronomy:

• Further work will be done on LNA & Feed Horns for the 6.7 GHz Receivers for a Dual Polarization system for Methanol Maser Observations.
  
• Development of a complete software simulation of the coded mask camera for ASTROSAT will be carried out. Tests on the fabricated prototype of the coded mask camera and comparison with the simulations will be conducted. Development of an image reconstruction algorithm for the coded mask camera and a software implementation of it will be undertaken.
  
• A simple feed similar to the one operating with the 220 GHz radiometer will be designed and fabricated to test the spare mixer expected to reach us in December 2000. Analysis of the data received from Hanle will be continued for determination of sky opacity. The existing radiometer at Hanle will be improved.
  
• Using programmable devices, prototype units of the Local Oscillator, clock generation and distribution circuitry will be designed and fabricated for the wideband Correlator. Testing of prototype multilayer sampler and Correlator boards will be completed.
  
• Intermediate Frequency system for the portable pulsar receiver will be designed using new generation components. Complete pulsar receiver will be tested after qualifying all the subsystems.
  
• The work on the Trapezoidal structure of the antenna feeds will be continued with an emphasis on the improvement of their VSWR. Ridged and corrugated horns will be tried out as alternatives for different frequency bands. Interference measurement will be continued in a more systematic way for a few months continuously in Gauribidanur.
  
• The Plessey FFT and PCI DAS system for the Ooty Pulsar Receiver will be validated. Necessary interface to the Sampler and the Pulsar Receiver systems will be incorporated.
  
• A Design of a configurable front end module will be taken up with features to accept multiple data inputs at different rates and bit-widths, format conversion facility for the input/output data, memory to double buffer and recirculate data and facility to arrange and distribute data to one or more backends.
  
• Fabrication of the prototype 12m pre-loaded parabolic dish with wire mesh reflecting surface will be undertaken.
  
• Design studies of a suitable mount for the prototype 12m parabolic dish will be undertaken.
  
• Preliminary design study of the following CCT related activities will be initiated:
  
  a) Backend receiver using suitable DSP components
  b) Local Oscillator System
  c) Fibre optic Communication system and
  d) Low Noise wideband frontend amplifiers using HEMT'S & RF ICs
  
  
• Under the ISRO-RRI collaboration on space astrometry, field trials will be conducted for the transmission and receiving systems for frequency transfer via INSAT. These systems will be enhanced with additional digital control to provide an accurate method for ranging geostationary satellites. A complete VLBI receiver will be built utilising the frequency reference disseminated from INSAT. A high speed data recording system will also be developed on a PC platform for use in VLBI and other applications.
  
• A collaborative project with CDAC, Pune is planned in the area of "Reconfigurable Computing Systems". This project will be aimed towards building a PC based high speed signal processing system, capable of directly handling signals of bandwidths upto 40 MHz and performing real-time spectroscopy and other functions like interference surveillance.
  Sophisticated device drivers will be developed under Linux for the PCI-card for high speed data acquisition. In addition to providing the capability for sustaining data transfer rates of upto 40 MB/s into the PC memory, the device driver also utilises features specially built up in the card to provide accurate time stamping required for VLBI applications.
  

Satyendra Nath Bose National Centre For Basic Sciences, Calcutta

The centre has active research groups in physics, pure and applied mathematics, computer modelling, and theoretical chemistry. It has also been a forum of contact among Scientists and has been regularly organising national and international symposia and conferences.

During the period under review, the Centre organised 19 regular scientific seminars and 6 non-scientific seminars. The Theoretical Physics Seminar Circuit (TPSC) for the country is being run by the Centre with the centres nad sub-centres all over the country. Under this programme, 9 seminars were organised

The Centre has initiated a new programme called "Associateship Programme". In this programme, eminent senior scientists are provided support for visiting the Centre. A similar opportunity is being launched for the young bright scholars to encourage collaborative research.

Other Academic Programmes:

• Winter Institute on Foundations of Quantum Theory & Quantum Optics, January 1-13,2000
  
• Mini Workshop on Growth Models, February 2-3, 2000
  
• Mini Workshop on "Quantum Field Theory : Applications to Condensed Matter Physics", March 13-14, 2000
  
• Symposium on Protein Structure at Bose Institute, February 2000
  
• IAPT Camp on Experimental Physics, June 2000
  
• International Conference on Magnetic Materials, at Saha Institute of Nuclear Physics, October 17-19, 2000
  
• India & Abroad : Research Perspectives and Projections in Condensed Matter Physics, January 2-4, 2001
  
• Workshop on Probability and Statistical Physics, February 19-23, 2001
  
• International Workshop on Nano Materials at Sha Institute of Nuclear Physics, February 2001

In addition to above, some other events were organised with the active collaboration of the Institutes like Indian National Science Academy; Indian Institute of Science, Bangalore; Society of Biological Chemists etc.

Sree Chitra Tirunal Institute For Medical Sciences & Technology,Thiruvananthapuram

The mission of the Institute is to develop indigenous health care technology while providing high quality patient care in advanced specialities and establishing training programmes integrating medical sciences and biomedical technology. The Institute therefore has a superspeciality Hospital for cardiovascular thoracic and neurological diseases, Biomedical Tedchnology Wing for R & D activities and the Achutha Menon Centre for Health Science Studies (AMCHSS) for research and training in public health. The emergence of the Institute into the 21st century was marked by new initiatives in health care technology and public health and significant advances in patient care services and academic activities. A summary of the important achievements in the last one year are given below:

Hospital Wing:

• Comprehensive Care Centre Parkinson's Diseases and other similar diseases, the first such Centre in India started functioning in full swing and surgery for Movement Disorder was introduced and more than 100 operations for Parkinson's disease were done successfully. The advanced technique for Deep Brain Stimulation and a novel technique of bilateral simultaneous subthalamotomy further marked the progress of the movement disorders programme.
• Endoscopic neurosurgery, endoscope-assisted microneurosurgery and a state-of-the-art facility for the treatment of cardiac rhythm disorders were started. Clinical trials on patients on the use of indigenously prepared fibrin glue in preventing CSF leak were initiated.
• Center for Comprehensive Epilepsy Care was further consolidated - the only facility of this kind in India. More than 300 operations were done for intractable epilepsy with excellent results.
• The student strength of DM/MCh degree and Postdoctoral Certificate Courses was 44 and the Master of Public Health degree programme had 7 scholars. There were 13 scholars for the Ph.D. programme, 19 students for Post Basic Nursing Certificate Programme and 13 scholars for various diploma programmes.

Biomedical Technology Wing:

A major programme for the implementation of a Quality System at the Biomedical Technology Wing was initiated. The objective of programme is to accredit the Wing as a TEST LABORATORY for the evaluation of biomaterials and medical devices to an international agency. The quality system will conform to the latest standard ISO/IEC 17025.

Establishment and maintenance of the quality and high standards of scientific R & D has become essential in the current scenario of globalisation. Being the premier institute of the country that is engaged in the research and development of biomaterials and medical devices, such accreditation would be a major step forward for the country as a whole. The advantages of having a quality system and accreditation are:

a) Assurance of a high level of quality in the R & D programmes
b) Attract international consultancy and testing
c) Enable the institute's industrial partners to market their products internationally.

The Quality Manual was released and the implementation is being carried out under special funding by DST with the overall co-ordination and monitoring by the Indo-French Centre for Promotion of Advanced Research, New Delhi with a tight 16-month schedule.

Focus on conversion of R&D work on biomaterials and medical devices into commercial technologies continued. The following table summarises the R&D status of important programmes: -

The technology transfer of the concentric needle electrode was completed and the industry, South India Drugs & Devices Ltd., Chennai has successfully produced and marketed over 1000 electrodes during the year.

An agreement for the collaborative development of a Hemoconcentrator (used for the removal of water and concentration of blood in the heart-lung bypass circuit after surgery, for re-infusion to the patient) was signed with the same company.

The scale-up project as envisaged in the MOU signed with M/s.Dynamic Orthopaedics Pvt. Ltd., Aluva has been completed and the subsequent Technnology transfer of the Hydroxyapatite bone graft material is in progress.

This year ten patent applications and one design registration were filed. Three Patents filed earlier have been sealed successfully. Fortyeight research papers were published in leading journals and one Book published by the staff of BMT Wing.

Achutha Menon Centre for Health Sciences Studies (AMCHSS):

The fourth batch of Master of Public Health (MPH) Course is continuing and overseas students began to seek admission for the course. MOU was signed with National Institute for Epidemiology (ICMR) to conduct an off campus Master of Applied Epidemilogy (MEA) Course.

International recognitions : (a) One of four universities entrusted with drawing up guidelines for international health research - others being Harvard, University of Natal (S. Africa) and University of Mexico. (b) Invited to be a member of the Standing Global Forum for Bioethics along with WHO, European Union and Organisation of African Union (OAU); (c) The first batch of MPH graduates reeived critical acclaim for their research at the Global Epidemology Conferences in Bangkok, Thailand (d) Rockefeller Foundation recognizes AMCHSS for consultancy in Public Health (e) The AMCHSS joins the network of Public Health Schools Without Walls in Africa & Asia.

Wadia Institute Of Himalayan Geology, Dehra Dun

The Wadia Institute of Himalayan Geology is devoted to basic research in Himalayan Geology and its related fields, including crustal evolution, basin evolution, natural hazards, palaeoclimate, water resources and Himalayan geo-data base. The research activities of the Institute are conducted through timebound project mode and the areas of its multidisciplinary research are organised into six major research areas such as Structure & Tectonics, Petrology and Geochemistry, Biostratigraphy, Sedimentology, Geomorphology & Environmental Geology & Geophysics. Highlights of research contributions made during the year 2000-2001 are summarised below :

Typical red bed with breccia conglomerates have been identified between Garbyang and Shiala Formations in the Tethyan Garhwal Himalaya. This event is assigned within Early to Middle Ordovician age based on the recovery of Ordovician conodonts. With this observation it is now possible to extend the Lower Ordovician break (late Pan African) of Lahaul-Spiti Basin of the Himachal Tethys Himalaya eastward to the Tethys Himalaya of Garhwal. We can thus suggest that the underlying "Ralam Conglomerate" of Tethyan Garhwal Himalaya definitely marks a Late Precambrian (Vendian) event which is not correlatable with the Lower Ordovician break of Spiti, H.P. The signatures of Vendian break are widely recorded throughout in the Himalaya as well as in the northern Peninsula.

The analysis of fauna from the Sangcha Malla Formation exposed in the Kiogad segment of Chamoli Garhwal Himalaya shows faunal similarity with those of Zanskar and Spiti during Albian-Aptian times (middle Cretaceous). The planktonic foraminiferal taxa from the Garhwal region suggest that during Campanian-Maestrichtian time deep marine conditions prevailed in the region. The late Cretaceous sediments in the region are tectonically overlain by melange zone comprising volcano-sedimentary rocks and 'Exotic Block'. This lithology points to tectonic activity possibly related to India - Asia collision which occurred during early Late Ypresian times.

Erection of Standard Reference Sections for the Tatrot, Pinjor and Boulder Conglomerate formations of the Upper Siwalik Subgroup were recognised near Chandigarh. Tatrot and Pinjor faunas were widely studied for the demarcation of these reference sections and migration. It is concluded that extinction or migration of the Pinjor Fauna was not simultaneous in all the regions and it varies from place to place and happened in between 1.72 Ma to 0.6 Ma. Tatrot and Pinjor faunas are also known from Jammu region. Both in Chandigarh and Jammu regions fauna does not show any change at the Neogene/Quaternary boundary. However, there are evidences that along N\Q boundary the process of extinction or migration of the mammalian fauna started. This event was further marked by the change of sedimentation pattern and intensification of the Himalayan Orogeny.

The Middle Siwalik lithounit from Mohand section has recently yielded a right first upper molar (RM1) of Parapodemus, a murid rodent. The immigrant murid taxon Parapodemus sp. is being reported from the Indian Siwaliks that too from an area that was hitherto not known for fossil vertebrates. Persistent efforts in developing Siwalik microfossil assemblage from a locality in Mohand section have so far yielded gastropods, ostracods, charophytes, fish teeth and an isolated murid molar, in order of abundance in our collection. Discovery of murid rodent from this section therefore has the benefit of sound geological perspective and its biochronological significance will provide temporal constraint to it.

Mio-Pliocene Siwalik sedimentary regime in the Kangra basin witnessed a major change-over from braided to meandering river systems and a remarkable decrease in channel density from eastern part of the basin (e.g., Jawalamukhi section) towards west (e.g. Nurpur section). Magnetostratigraphy in Ranital as well as Kotla sections records an enhanced rate of sedimentation and change in magnetic fabric parameters at ~ 10 Ma. Temporal sediment dispersal pattern based on sand-body geometry, paleoflow variability (from field as well as magnetic data), clast composition (in field and thin section) suggest large scale channel migration from SSW to SW in the central part of the basin (Ranital section). It further suggested a southward basin-tilt in response to initiation (?) of Main Boundary Thrust (MBT) at ~ 10 Ma. Framework composition of sandstone suggest sedimentary (mainly argillites, sandstones and limestone) > low grade metamorphics > acid-basic igneous rocks rich source area terrain. Temporal trends in the framework mineral components reveals a variability in source area climate from semi-arid to humid. Onset of Pliocene period records a major change in detrital magnetic mineralogy and anisotropy as a result of change in source rock assemblage.

Plant fossils recovered from Chhongtash Formation have been identified as a leaf of Noeggerathiopsis, a portion of a Gangamopteris, some unidentifiable plant types and a portion of a large equisetalean stem. The dominance of monosaccates in these assemblages is similar to the Talchir or Karharbari (Early Permian) Gondwana assemblage of India. However, the presence of striate bisaccates in significant amount (20%) favour a late Asselian (~ 280-275 Ma) age. The presence of calcareous microfossils in the thin sections confirm sedimentation under marine conditions. The occurrence of fusulinid-bearing limestones as reported by earlier workers is also typical of much of the northern margin of Gondwana. Thus, the work carried out suggest that, the Early Permian plant fossils and associated palynormorphs from the marine sequence of Chhongtarh Formation show affinity with those found in marine Lower Gondwana flora recorded in the Talchir coal field in the Indian subcontinent. This supports the contention that during the Early Permian period, the Karakoram plate was Peri-Gondwanian.

Reconnaissance survey of the Quaternary deposits in Ladakh and Karakoram area revealed that remnants of paleolake sediments around Khalsar and Tangste are promising repositories of the Quaternary climate history of the region. Peat deposits developed on marshy grounds in flood plain areas of Nubra (near Panamik), Shyok (near Deksit and Hunder) and Mubuk (near Tangste) are also of good significance particularly for revealing the Holocene climate history. Rock engravings of double-humped camels, Ibexes and horses were also discovered in Nubra valley. They are engraved by pecking in dark rock varnishes developed on very big granite boulders. These engravings are possibly of ~ 5000 yr B.P. (i.e. Neolithic period) and represent very good archaeological record for paleoclimate interpretation.

Indus Suture Zone (ISZ) preserves remnants of the Neo-Tethyan ocean floor and the arcs that developed due to subduction of the former under the Eurasian plate. The Zildat melange has a thrusted northern contact with the Nidar Ophiolitic complex. The latter consists of serpentinised ultramafic rocks, gabbro and basaltic-andesites. The Nidar gabbroic and volcanic rocks, enriched in LILE and LREE, have similar or lower abundance for the lesser incompatible elements including Nb, P, Zr, Ti, Y, Yb compared to typical N-MORB. This is also indicated by their positive Sm/Nd values + 0.1766 to + 0.3447 for the gabbro, probably indicating their derivation from a depleted mantle source. Gabbros of the Nidar Ophiolitic complex dated about 140 ± 32 Ma by a nine point Sm-Nd mineral-whole rock isochron (M.S.W.D.= 1.84; 143 Nd/144Ndi=0.512836 (0.000053; (Ndt140 Ma = + 7.4). These are inferred to represent the intra-oceanic island arc equivalent to Dras volcanics of Western Ladakh and the Chalt volcanics of Kohistan.

Field investigations in Eastern Ladakh showed complex association of chert with volcanics. It indicates that the volcanic eruptions were frequent and did not allow full development of chert/Jasperite and are present in the form of nodules. The layered Jasperite and Chert on volcanic nucleus are common in this lithology. They represent mixed volcanic and chert development. In the Nidar chert member the sedimentary sequence containing dominantly chert and jasperite with other sedimentary sequence are best developed. In this area especially near Rango (Hanle) the thick sedimentary succession dominated by argillaceous facies with exotic blocks of Eocene limestone suggests post Eocene tectonic activity.

Pinjore doon sediments representing alluvial fan dates around 40 ka in basal part of the exposed section. Pilot sampling for Magnetic polarity studies in the Pinjor Dun sediments inferred a consistent normal polarity except a weak short reversal event. Supporting the TL dates, it brackets the Pinjor Dun sedimentation in the Brunhes Normal (<0.78 Ma). The weak short reversal (being re-investigated) depict the occurrence of Laschamp excursion (40 ± 5 Ka).. The magnetic susceptibility stratigraphy indicates a poor correlation suggesting rapid lateral lithologic variations due to differential detrital influx.

The results obtained so far from study of structural evolution of the Kangra re-entrant indicate that the three-dimensional geometry of the Foreland basin varies with the number of basement faults, displacements along them, tectonic load on the Main Boundary Thrust, and displacement along the klippen, detachment thrust in the Lesser Himalaya. Results from balancing a few isolated sections in a large area can be misleading because a simple restoration of deformed sections by bringing the inclined layers to horizontal position along thrusts may provide wrong estimates of shortening. These shortening estimates need to be corrected by a factor that depends upon the initial geometry of the basin. In absence of this correction all previous estimates of total shortening and shortening rates appear to be erroneous. Earthquake predictions based on these data are not reliable.

Three great earthquakes with magnitude greater than 8 struck the Himalayan belt within a span of 50 years, and the 1905 Kangra earthquake is one among them. The meizoseismal region of this earthquake in the Kangra - Chamba region is analyzed for seismotectonic interpretation on the basis of the major structures and the present day seismic activity. The microseismicity recorded by a network of 12 stations for a period of 16 months spanning 4 years (1993-1996) shows the activity is mainly concentrated over the Main Boundary Thrust (MBT) and Panjal Thrust (PT) zones and the Chamba Nappe region. A NE-SW vertical section reveals that the majority of events are concentrated within a depth range of 5 to 18 km, of which majority of the foci lie between 12 and 18 km. The base of the microseismicity zone is interpreted as representing a contact or a decollement plane between the top of the Indian plate and the Himalayan rock formations. This decollement plane is northern continuation of the detachment observed in the Sub Himalaya in reflection profile. The southward propagation of the Chamba Nappe as well as the PT and MBT zone over the flat part of the detachment causes accumulation of strain energy in this region.

The tidal acceleration due to the Moon and the Sun in the post-glacial period suggests the reactivation of pre-existing structures to the current stress field. This has been computed by Fortran-77 programme on the basis of Longman (1959) formula by taking 48 hours gravimeter readings recorded with half an honour interval at the Wadia Institute of Himalayan Geology (WIHG), Dehra Dun, India, on 16th and 17th January, 1989. The localized built up of stress on the potentially seismogenic feature is due to the ambient stress field. The stress amplification in the Himalaya, initiation and termination of micro level seismicity at fault ends or bends may be due to localization of strain in the mid-lower crust and lateral variation in density due to glacial rebound and crustal elasticity.

Using high resolution IRS-IC/ID satellite data, an area of 940 km2 , covering Nyoma, Nidar, and Kyun Tso regions was extracted from the digital data and processed. While the earlier published geological maps of the area show the presence of a number of lithological units, this study has demonstrated that refined and systematic lithological and structural inferences can be made from the high resolution Indian Remote Sensing Satellite data. An improved version of the lithologic map for the Nidar area has been prepared using the colour composite images as a mapping base. This gives a more precise synopsis of the distribution of lithologies as compared to the previously published maps. Some features existing on the image-based map which do not appear in the previous map demand further field verifications. Besides, an attempt has also been made to recognize the shrinking pattern of the Kyun Tso lakes. It is noticed that the dimension of these lakes has continually fluctuated with time due to the ongoing compression in the collision regime and possible climatic influences. The certainty of rock distributions and faults obtained from interpretations of the IRS IC/ID images in conjunction with ground data is being used to strengthen our ongoing studies of the ophiolites of the Indus Suture Zone.

Three distinct overthrusted crystalline thrust sheets,namely, the Sewak (=Chail), Lalpani (=Jutogh), Mayodia (=Vaikrita) form a continuous belt in the Lohit and Dibang valleys of Eastern Arunachal Pradesh thereby indicating foreland propogating thrust system. A large number of neotectonically active faults/thrusts have also been recognized in this part of Himalaya which not only are displacing the various tectonic boundaries but also causing damage to recently constructed river bridge at Rohing in Dibang valley and subsidence of road at Lalpani in Lohit valley and at Hunli in Dibang valley. Also a NE-SW trending big palaeolake stretching 12 km long, 5 km wide and 200 m deep has been discovered at Anini in Dibang valley. A persistent 0.3 to 0.5 m thick horizon of lacustrine deposit comprising peaty clay capping the lake sediments promises to hold important palaeoclimatic clues possibly encompassing late Pleistocene- early Holocene interval.

Use of asymmetric binary thermodynamic solution models for the refinement of the alkali feldspar - muscovite geothermometer have been investigated were applied to Central Crystalline Complex and Almora Crystallines. Monte Carlo method is applied for computing propagation of errors in biotite-garnet geothermometry with reference to P-T path analysis and inverted metamorphism in Almora Crystallines. It is interpreted that in Almora Crystallines, T varies from 500o to 700oC ± 30o C and P from 6 to 9 ± 1 kbar. Spatial distribution of data indicates inverted metamorphism.

Ore petrographic, ore chemical., fluid inclusion and stable isotope studies have been carried out on the sulphide mineralization of Dhanpur area in Chamoli District, Uttaranchal. These studies reflect a volcano-sedimentary origin for the sulphide mineralization as they were initially deposited in a stratabound submarine exhalative environment wherein rapid precipitation occurred in free space. It is also evident that the present distribution is a consequence of later tectonic event during Tertiary period. Studies of the fluids in anorogenic, peralkaline Siwana Granite, Malani Igneous Suite, Western Rajasthan show the presence of an early hydrosaline melt phase during granite crystallization, whereas enrichment of carbonic fluid had facilitated formation of aegirine bearing granite. They record a temperature of > 575o C. Presence of NaCl-H2O and carbonic fluids trapped in Siwana Granite may imply crust-mantle interaction.

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