RESEARCH INTERESTS
¨ Depositional and diagenetic modeling of Cretaceous-Tertiary deposits.
¨ Documentation of environmental changes across major geochronological boundaries such as Maastrichtian-Danian and Cenomanian-Turonian through integrated analyses of lithology, petrography, mineralogy (bulk and clay), major and trace element geochemistry, stable isotopes and strontium isotopes, sea level changes and biota.
¨ Integrated sequence and chemostratigraphic modeling of Cretaceous-Recent deposits.
¨ Establishment of Computer Information System for statistical discrimination and prediction of depositional units (litho, bio, chronostratigraphic units, sequences and chemozones, sedimentary microenvironments of deltaic systems, etc, to aid in petroleum exploration and stratigraphic correlation.
¨ Sediment characteristics of modern depositional environments ranging from riverine-brackish-marine regimes.
¨ Dynamics of estuarine mixing, sediment and solute transport to oceans, pollutant assimilation and nutrient regeneration capacities of estuaries.
¨ Dynamics of coastal geomorphology and sedimentation patterns under the influence of changes in sea level vis-à-vis shoreline, landuse, and neotectonics; their implications on deltaic evolution and coastal zone and environmental management.
RESEARCH WORKS DONE SO FAR
Doctoral research work at Bharathidasan University
Depositional and diagenetic models of the carbonates of the Kallankurichchi Formation (Lower Maestrichtian) of Ariyalur Group, Cauvery basin, south India were developed through systematic field mapping, standard microfacies analysis, major, minor, trace elemental and isotopic data and statistical analyses. The study had recorded six standard microfacies types and recognised the depositional regime to be of shallow warm water, normal saline, moderate to high energy conditions in a distally steepened ramp setting. Recurrent storm events and sea level changes were also revealed. Prevalence of marine-phreatic, meteoric vadose and phreatic zones of diagenesis were recognised under eo, meso and telogenetic phases. Open system of diagenesis under dissolution-precipitation mode of transformation was found to have dominated other modes of diagenesis. The control of siliciclastic influx over the carbonate deposition and/or accumulation and the control of depositional texture over later stage diagenesis were also brought with geostatistical analyses of modal petrographic data and geochemistry. It was also demonstrated that with the help of petrographic and geochemical data, the standard microfacies types and carbonate petrographic types could be discriminated statistically. The work includes for the first time records in the study area on Trace fossil, storm deposits, comprehensive depositional and diagenetic models, sea level changes during lower Maestrichtian, dolomitisation and associated hydrocarbon development and/or accumulation and structural configuration of the study area. With the data and models generated, about 30 research articles in the national and international journals have been published/submitted for publication.
Post doctoral research work at IIT-Kharagpur
Detailed field mapping, recognition of stratigraphic boundaries, faunal association coupled with petrographic textural studies and point count data were attempted to establish the depositional model of the Tertiary sequence of the Kutchch region of Western Gujarat, India. Multivariate statistical discrimination of the petrographic point count data had indicated that it is possible to recognise and predict the lithostratigraphic, petrographic and standard microfacies types of carbonates to the tune of 78, 100 and 90-100 % accuracy respectively. With the data generated, two papers have been prepared. One paper has been published (on statistical prediction of carbonate petrographic types, standard microfacies and facies belts and lithostratigraphic units) and other one on prevalent sea level changes, sequence stratigraphic set up and implications on hydrocarbon potential of the basin is in the process.
Work carried out as Research Scientist at Delta Studies Institute, Andhra University
The Ministry of Petroleum and Natural Gas and the Oil and Natural Gas Corporation Limited, have established a research institute for conducting advanced research programmes to support the ongoing exploration programmes of India. I was the first scientist to join the Institute and a number of studies were initiated/conducted during my tenure there.
The information that India spends nearly 80 % of its foreign exchange reserves on importing petroleum and petro-products, coupled with increasing domestic demand-indigenous supply ratio, failure to identify new oil fields and develop known fields have contributed significantly to such a state of affairs. Although the east coast sedimentary basins of India are considered to be hosts of promising hydrocarbon reserves, three major problems were found to thwart successful oil exploration and field development programmes, viz.,
¨ as the reserves are confined to paleodeltaic systems of Krishna-Godavari basin, accurate recognition of micro-sedimentary environments are necessary as far as this basin is concerned.
¨ the occurrence of stratigraphic traps and the absence synergy in stratigraphic set-up for the onland and offshore counterparts of the Cauvery basin thwart successful exploration in this basin.
¨ absence of improved understanding of sedimentary processes in the light of modern techniques.
These problems were taken up for detailed study during the tenure of Research Scientist. The research works initiated in the Delta Studies Institute include,
¨ Documentation of characteristics of the deltaic micro-sedimentary environments (21 sub-environments) through systematic granulometric, grain morphologic, mineralogic, geochemical and geophysical parameterisation and to evolve a linking mechanism for the modern sedimentary characters of Cauvery, Krishna, Godavari, Pennar and Mahanadi deltas and the palaeo deltaic sequences (from the rock samples collected from sub-surface cores recovered by ONGC). So far, documentation of Krishna, Godavari and Pennar deltaic sediments, sub-surface samples of Krishna and Godavari deltas were completed and the remaining samples are being processed. The data generated during the first phase, when applied with statistical techniques, has given encouraging results, such that there is a strong possibility of prediction of depositional environments of unknown samples from the dataset generated. The environmental discrimination model developed with the study had been applied to Tertiary rocks of Kutch area and Cretaceous rocks of the Cauvery basin and found to be applicable to 86 to 100 % success rate. Enthused by these results ONGC has sanctioned project for conduct of such studies in all the major deltas of India and promised to supply sub-surface rock samples from different basins for establishing an automated computer system. The Department of Science and Technology, New Delhi has also sanctioned a specific project for establishing a computer model for the Krishna-Goavari basin.
¨ Salient features brought out during this tenure include, development of a computer assisted environmental discrimination and prediction scheme, Quaternary sea level changes and sedimentary facies characteristics of the Godavari and Krishna deltas, geomorphologic evolutionary history of the Godavari and Krishna deltas and estuarine sedimentary processes and their control over geochemistry of estuarine sediment and water. A new water sampler for estuarine and shallow marine water sampling has been developed and put to use. These studies have resulted in over 30 research articles in national and international journals, four technical and consultancy reports and a patent for the instrument design.
¨ In order to address the problem of lack of improved understanding on the sedimentary processes in the light of modern techniques, studies were taken up towards chemo and sequence stratigraphy of the Cauvery basin, wherein improved interwell and onland and offshore stratigraphic correlation would help evolving a successful exploration strategy. The initial results are encouraging that led to few national and international publications.
Work carried out as Research Associate at Dept.Geology, National College
Council of Scientific and Industrial Research, New Delhi, has awarded Research Associateship to conduct the field work in India, required for sampling for the work on the chemostratigraphy of the Cretaceous-Tertiary strata of the Cauvery basin, to be conducted in Karlsruhe University, Germany. The onland exposed part of the Cauvery basin has been mapped in 1:50,000 scale (the first ever in this part of the basin) and detailed information on microscale lithology, sedimentary and tectonic structures, faunal and floral assemblages, stratigraphic boundaries and ichnofauna were collected. This work, coupled with initial laboratory analyses has resulted in preparation of three papers (one on revised lithostratigraphy of the Cauvery basin, another on major sea level changes and the response of sedimentation system, sequence stratigraphy and the third on a record of a new trace fossil and first ever systematic record of fluvial sedimentary unit sandwiched between Cretaceous marine strata.
Work carried out as Visiting Scientist, Germany
It was concentrated towards recording events that occurred during Cretaceous-Tertiary periods in the Cauvery basin and the response of the sedimentary system to those changes through geochemical markers. The results indicate that there were major sea level changes all through the history of the basin. The tectonic influence on sedimentary system was minimal during latter part of the evolutionary history of the basin. Samples were analysed for mineralogical, major and trace elemental concentrations and stable isotopic and rare earth elemental analyses. Occurrences of coeval sea level changes and resultant geochemical compositional shifts at scales ranging from second order to infra fourth order were documented. A prototype model for stratigraphic and chronological prediction of unknown samples from Cauvery basin has been evolved and works are progressing to fine tune the model in order to make the model operational. It is believed that once operationalized, the model would serve as a baseline for global stratigraphic correlation. This study has also yielded insights on Cretaceous-Tertiary transition events in the Cauvery basin as explicit in oxygen, carbon and strontium isotopic and trace elemental anomalies and their relevance in global environmental deterioration scenario before and K/T boundary that culminated in higher faunal turnover at about 65.4 Ma.
Work done during current tenure as Pool Officer
Collaborative research has been initiated in terms of increasing the resolution of chemostratigraphic setup of the Cauvery basin towards Milankovitch band through documentation of additional chemical data in furtherance of research carried out as Humboldt Fellow, Germany; Generation of mineralogical and petrographic data of Barremian-Danian strata of the Cauvery basin and contributing to improving the chemostratigraphic setup of the basin and documentation of environmental changes prevalent during the important transition periods across Cenomainan-Turonian and Maastrichtian-Danian through integrated analyses of sedimentological, geochemical, stable isotopic, trace and rare earth elemental, strontium isotopic, mineralogical, petrographic and paleontologic data. For the first time, turbiditic deposition has been recorded from this basin. In addition, elucidation of ongoing geomorphologic, sedimentologic, geochemical and landuse dynamics of the Krishna and Godavari deltas towards sound environmental management practices was also being carried out. These studies have resulted in submission of few manuscripts to national and international journals. In addition, few research proposals are being drawn for funding by national and international agencies.
