bluuebunny/crossref_metadata_2025 huggingface dataset:
Ignimbrite, Ash-Flow Tuff and Basic Volcanics of the Daling Formation of Sikkim Himalaya: Geotectonic Implications
Authors: Sinha-Roy S.
Published: November 2024

Ignimbrite and ash-flow tuff's have been identified within the graywacke unit of the Daling turbidite sequence of the Sikkim Lesser Himalaya. These, together with basic flows constitute the basal part of Proterozoic Daling Formation. Geochemistry of these rocks indicates that the tuffs are derived from calc-alkaline volcanism while the basic flows have MORB characters. It is concluded that within the Daling ocean (ProtoTethys or Palaeo-Tethys) graywacke was deposited as a trench prism, the tuffs were the products of island-arc explosive volcanism, and the basic flows, of spreading in the back-arc basin. This island arc system disappeared due to tectonic activity which deformed (the first recognisable deformation) the Daling rocks. This event probably represents the Caledonian orogeny in the Himalayas.
Silicified Cyanobacteria from the Cherts of Archaean Sandur Schist Belt-Karnataka, India
Authors: Naqvi S. M. , Venkatachala B. S. , Shukla Manoj , Kumar B. , Natarajan R. , Sharma Mukund
Published: November 2024

Silicified cyanobacterial remains are recorded from the black cherts interbedded in the Donimalai Formation of the Archaean Sandur Schist Belt and amorphous organic matter in the stromatolites underlying Deogiri Formation of the same belt. The presence of elemental carbon at the fringes of the cyanobacteria is confirmed by microprobe analysis. Carbon (d13C= -1.4 ± 0.5% vs PDB) and oxygen (d18O= + 10.6±0.5% vs SMOW) isotopic ratios and the presence of cyanobacteria extend the existence of photosynthetic activity into the Archaean.
On the Heavy Minerals of Lower Gondwana: Sediments of Ghugus Coalfield, Wardha Valley, Maharashtra, India
Authors: Singh Mahendra P. , Singh R. M.
Published: November 2024

Heavy mineral analyses of Talchir, Barakar and Kamthi sediments (Lower Gondwana) have been carried out with a view to elucidate their distribution, relative abundance, nature and behaviour. The heavy mineral separates show the presence of garnet, zircon, tourmaline, rutile, epidote, staurolite, chlorite, kyanite and opaques-including ilmenite, magnetite and hematite. It is inferred that the Talchir sediments are mainly the disintegrated products of high-rank metamorphic terrains, granitic plutons and pegmatitic veins. The heavy mineral associations of Barakar and Kamthi sediments reflect the dominance of basic and acidic igneous plutons together with the possibility of pegmatitic veins in the source area.
Mineralogy and Geochemistry of the Calcretes in Alluvial Sediments from Pune, India
Authors: Dessai A. G. , Warrier Sudha
Published: November 2024

The calcretes in the alluvial sediments from Pune district, Maharashtra occur as hardpan, powdery, laminated, concretionary and pedotubule horizons. The calcretes are associated with clay minerals belonging to the smectite, chlorite and kaolin groups. The chemical analysis of the calcretes indicates that they are predominantly composed of calcium-carbonate and silica, (Cao: 33 to 37%, SiO2 : 25 to 31%) with magnesium in very subordinate amounts. Trace elements present include Sr, Zr, V, Nb, Y, and Cs. On the basis of textural, mineralogical and chemical data, it is shown that the calcretes have resulted from two different processes, viz., by accumulation in the zone of fluctuation of groundwater tabie and by precipitation from percolating water during pedogenesis.
The Distribution of Intensity Associated With the Great 1897 Assam Earthquake and Bounds on the Extent of the Rupture Zone
Authors: Molnar Peter
Published: November 2024

The great 1897 Assam earthquake probably was associated with underthrusting of the Indian subcontinent beneath the Shillong Plateau, and as such it absorbed part of India's convergence with the Himalaya. Seeber and Armbruster (1981) concluded that slip occurred on a fault that extended north beneath the Himalaya and south beneath much of what is now Bangladesh and that the east-west dimension of the rupture was 550 km. A reassessment of the information given by Oldham (1899) leads me to favor Oldham's inference that the length of the rupture was only about 200 km. The southern edge of the rupture was more likely at the southern edge of the Shillong Plateau than south of it. The possibility that the rupture extended beneath the Himalaya seems to be permissible but not provable from Oldham's observations. Thus, it would be unwise to assume that the 1897 earthquake released the strain that had accumulated east and west of the Shillong Plateau since the last earthquakes in those areas. Although the risk of a large earthquake in the near future in the segment north of the Shillong Plateau is probably less than that in the segments of the range to the east or west, the 1897 earthquake may not have relieved the strain in that segment as well. Given the evidence that the 1897 earthquake was a very large earthquake, however, it seems unlikely that there will be a repeat of such an event in the next hundred years, or more.
Agnostid Fauna from the Middle Cambrian of Kashmir
Authors: Shah S. K. , Sudan C. S.
Published: November 2024

Agnostid fauna from the Middle Cambrian Solenopleura-Tonkinella Zone of northwestern Kashmir is described. It includes Peronopsis cf. tramitis, P. amplaxis in addition to a new species, P. extensa and two left under open nomenclature. The other taxa include Acadagnostus acadicus, A. scutalis and Pentagnostus cf. anabarensis. The assemblage is correlated with the Ptychagnostus gibbus zone of Australia and North America.
Geochemistry and Petrology of Xenolith-Bearing Lamprophyres from Murud-Janjira, Raigarh Dist., Maharashtra, India
Authors: Dessai A. G.
Published: November 2024

The N-S trending lamprophyre dykes from Murud-Janjira contain felsic and ultramafic xenoliths alongside unusually zoned clinopyroxene phenocrysts and xenocrysts that are found in an analcime base. On the basis of mineralogy and chemistry, the lamprophyres have been classified as monchiquites.

The lamprophyres are probably emplaced along a system ef chasmic faults that are parallel to the West Coast arm of the Khambat triple junction. They may represent flank activity of the mid-ocean ridge anomaly and are the products of tlte waning stages of Deccan magmatism.
A Reassessment of Stratigraphy of Bagh Beds, Barwah Area, Madhya Pradesh, with Description of Trace Fossils
Authors: Bauve R. M.
Published: November 2024

A reassessment of the stratigraphy of Bagh Beds in Barwah area, Madhya Pradesh reveals that only the basal member, Nimar Sandstone, is present with calcareous facies resembling the Coralline Limestone developed predominantly towards its top and followed up by sandstone shale alternations. Other younger members i.e., the Nodular Limestone, the Lower and Upper Coralline Limestone or the Deola and Chirakhan Marl are absent in this area.
Relationship Between Maceral Composition and Carbonization Properties of the Coal Seams in the Northwest Corner of Parej Area, West Bokaro Coalfield, Hazaribagh, Bihar
Authors: Kumar Vijay
Published: November 2024

Carbonization properties increase very sharply with increasing proportions of reactives and reactive indicesi.e., they are directly proportional to each other. The samples giving coke types between G and G3, caking indices between 19/21 and 29/31 and swelling indices between 2 and 5 1/2 with reactives between 56.6% and 70.1% and reactive indices between 1.30 and 2.34 are prime coking in characters. The samples giving coke types above G3, between G3/G4 and G8/G9 and below G, between D/E and F/G may be utilised as primary blends in coal preparation for the manufacture of metallurgical coke.

Both sulphur and phosphorous are within permissible limits for coals to be treated as coking to prime coking. Ash in the coal seams may be brought down by beneficiation within permissible limits for metallurgical coke. The beneficiation will also help to improve the presently determined carbonization properties and to decrease sulphur and phosphorous contents in the seams.
Oryctocephalid Fauna From the Cambrian of Spiti
Authors: Shah S. K. , Paul Sat
Published: November 2024

The oryctocephalid fauna from Middle Cambrian of Spili is described. In addition to Oryctocephalus salteri Reed, it includes Oryctocephalus opiki Shergold and Oryclocephalites cf. sulcatus Shergold, not recorded from India so far. The oryctocephalid fauna characterizes a distinct horizon at the base of Menevian (upper Middle Cambrian) which corresponds to its position in Australia (Templetonian).
Petrography and Major Oxide Chemistry of The Archaean Granitic Rocks of the Medak Area, Andhra Pradesh
Authors: Sarvothaman H. , Leelanandam C.
Published: November 2024

The model compositions of the Archaean granitic (s.1.) rocks of the Medak area in Andhra Pradesh correspond to tonalite, quartz diorite, granodiorite. adamellite, quartz monzodiorite, granite (s.s.) and alkali feldspar granite. The granitic units show retrograde effects such as albitic rims around plagioclase at K-feldspar contacts, and inclusions of chlorite, epidote and ores in hornblende; anti-rapakivi mantling of plagioclase by K-feldspar is common; K-feldspars show incipient microclinisation. The diagnostic mineral parageneses of the granitic units indicate an overall metamorphism under greenschist facies conditions though locally culminating in amphibolite facies.

The major oxide chemistry reveals that the granitic rocks are divisible into three types. (i) tonalite-quartz diorite suite; (ii) calc-alkaline granites; and, (iii) potassic granites. Tonalites and quartz diorites seem to have formed from a melt which is produced by partial melting from a potassium-depleted sub-crustal (or a mantle) source; the melts of calc-alkaline and potassic granites are probably produced by repeated anatexis from an early sialic crustal source.
Juvenile Sauropod Dinosaur from Upper Cretaceous Lameta Formation of Panchmahals District, Gujarat, India
Authors: Mohabey D. M.
Published: November 2024

Partial Skeletal remains of a juvenile sauropod have been recovered from one of the dinosaur egg clutches found in arenaceous limestone of the Upper Cretaceous Lameta Formation in Dholi Dungri in Panchmahals district, Gujarat. India. The estimated length of the skeleton is 40 cm. It is represented by vertebral column, humerus, scapula, ilium, skull fragments and other indeterminate fragments. This paper records the first find of a juvenile dinosaur in India.
Transport and Fractionation of Pb in River Sediments from the Indian Sub-Continent
Authors: Subramanian V. , Van Grieken R. , Van T'dack L.
Published: November 2024

The distribution of Ph and As in the bed sediments as particulates from the Ganges. Brahmaputra, Godavari, Krishna and Cauvery rivers has been studied. While the Pb levels in bed sediments vary from a low of 2 μg Pb/gm in the Ganges to a high of 32 μg Pb/gm in Godavari, the corresponding particulate Pb load varies by a factor of 5-40 times the bed load from a low value of 5 μg Pb/gm particulates of Krishna to a high value of 1075 μg Pb/gm in the same river. Downstream variations in all rivers are generally erratic both for particulate and bed Pb-Ievels. All the river sediments indicate a very good correlation between Pb and As on the one hand and heavy metals such as Fe, Zn, Cu etc. on the other.

The Himalayan river sediments generally exhibit strong grain-size control on the fractionation of Pb and As, whereas the peninsular rivers do not show a systematic partitioning of Pb and As in various size populations.
Observations on Some Manganese Nodules from the Central Pacific
Authors: Roonwal G. S. , Vijaya Kumar U.
Published: November 2024

Manganese nodules have been studied under the microscope with the use of reflected light and scanning electron microscope. Around the nucleus accretion of the diagenetically derived material is seen to take place giving rise to columnar or dendritic texture. Away from the nucleus textural variation and abrupt discontinuity in the nodule growth is observed indicating changes in depositional characteristics of ferromanganese oxides as the nodule grew. The intermingling of manganese oxides and silicate minerals, and sometimes iron oxides is common, generating discontinuities within the nodule texture. Scanning electron microscopic observations indicate that the material deposited on the surface is crystalline, non-crystalline, inorganic. organic or detrital in nature giving rise to different surface features such as botryoidal, consolidated compact layering or unconsolidated porous surface appearance.
Laterite-Bauxite of Paduvari Plateau, South Kanara, Karnataka State
Authors: Khanadali S. D. , Devaraju T. C.
Published: November 2024

The different litho-units of the weathering profile of Paduvan Plateau show clear gradation contacts and contain relics of nearly all the minerals which are native to the underlying granitic gneiss. Mineralogically, the latent profile is dominated by gibbsite with kaolinite compared to lithomarge and goethite-hematite in the ferruginous laterite horizons. There is evidence of development of gibbsite both by the direct alteration of feldspar of the precursor rock and by the desilication of kaolinite. Four stages of transformation represented by altered gneiss, lithomarge, laterite and aluminous laterite bauxite are maintained in the weathering profile. As compared with the basalt derived laterite profiles, the Paduvari occurrence is characterised by relatively strong depletion of soda and potash and enrichment of ferrides. The field, petrographic mineralogical and geochemical data provide enough evidence of formation of Paduvan laterite profile by the in-situ chemical weathering of the underlying granitic gneiss and the aluminous laterite-bauxite by the 'in-situ chemical reworking' of laterite.
Engineering Properties of the Damuda Sandstones and Shales from the Eastern Indian Coalfields
Authors: Ramachandran C. , Narasimham C. V. L.
Published: November 2024

The compressional wave velocity, compressive strength, tensile strength, permeability and density are measured for some coal-bearing rocks of Eastern India. The ranges of compressional wave velocities for the different rock types are presented. It is observed that the compressional wave velocity in sandstones increases linearly with increase of density, compressive strength, tensile strength and Young's modulus. The absorption coefficient of compressional waves in sandstones decreased linearly with increase of Young's modulus. The permeability, determined in a few sandstone samples, increased with porosity.

Empirical relations obtained by least squares technique are also presented, relating to the variation of compressional wave velocity with density, Young's modulus and the strength of sandstones. The results would find application in coal exploration and extraction.
Pollution of the River Ganga by Municipal Waste: A Case Study from Patna
Authors: Sharma C. B. , Ghose N. C.
Published: November 2024

The present study reveals that chemical pollution around Patna in the river Ganga (av. B.O.D. 2.3 ppm) is rather insignificant. but the bacteriological pollution is alarmingly high (av. 904/ml of most probable number, MPN, count) within 10 metres of the right bank. The higher MPN count of drain water (av. 6.2 × 106/ml) is drastically reduced to seven thousand times within a distance of 500 metres in the downstream. High regenerating capacity of Ganga has been ascribed to be due to the higher concentration of sbortlived isotope of radium in comparison to that of its tributaries, viz., Son and Gandak.
Some Industrial Waste Effluents in Asansol-Raniganj Region and their Impact on the Damodar River Water Quality
Authors: De Anil K. , Sen Asit K. , Modak D. P. , Karim Md. R.
Published: November 2024

The industrial waste effluents from four industries in Asansol-Raniganj industrial complex were examined. The contamination of Damodar river water by pollutants: ammonia, nitrate-nitrite, phosphate, sulphide, phenol and other organic matters, tannin-lignin and mercury, is confirmed.
Planimetric Response of the Kerala Shoreline to the Monsoon of 1979
Authors: Thrivikramji K. P.
Published: November 2024

Beach profiles were surveyed twice in the year 1979, along transects placed approximately 10 km apart on the Laccadive sea shoreline, from Kanyakumari (Tamil Nadu) to Thalappadi (Kerala) - a distance of about 650km. Profile changes are analysed in the light of geomorphology, shelf width and gradient, wind data and ship-reported wave data. Cumulative and catastrophic shift of beach sediment during the sw monsoon of 1979 has been calculated. An apparent dichotomy exists between the beaches of northern Kerala (Malabar) and southern and central Kerala in that the beaches of Malabar are less severely eroded than those of Southern and Central Kerala.
Environmental Impact of Phosphate Mining in India
Authors: Banerjee D. M.
Published: November 2024

Phosphorus plays an important role in terrestrial environmental management. Mining of phosphate ore without observing necessary safeguards can cause enormous damage to the general ecosystem and in particular to the aquatic bodies which receive excess P influx. A careful enumeration of the actual mining situations observed in five phosphate mining centres brings out the fact that while some damage to the surrounding environment has already been caused due to mining operations in the area, more serious hazards are forthcoming, if suitable legislations are not enacted to contain them. Case studies include mines at Jhamarkotra, Matoon-Kanpur, Jhabua, Maldeota-Durmala and Purulia.
Contamination of Soil, Water and Vegetation by Copper, Lead and Zinc Ore Mining and Smelting at Khetri and Zawar (India)
Authors: Haque Md. Asrarul
Published: November 2024

Soil, water and plant samples were collected from Khetri where copper mining and smelting are preformed and from Zawar where lead-zinc ores are mined and concentrated. Khetri samples were analysed for copper and Zawar samples were analysed for lead and zinc. The samples analysed showed contamination in both the localities. There is sufficient evidence to show that mining and related activities were responsible for contaminating soil, water and vegetation. Smelting of ore caused higher degree of contamination. Effluent from smelting operations on mixing with natural water bodies made the water acidic.

Different species of plants accumulated different concentrations of metals from the same soil. Those species whose root portions are consumed can cause metal contamination.
Morphology and Morphometry of the Naini Lake, Kumaun, Lesser Himalaya
Authors: Rawat J. S.
Published: November 2024

The curvilinear lake (viz., Naini Tal) encompassing an area of 1,758 m2 exhibits such morphological features as transverse ridge dividing the lake into two parts: scarps, debris fans fringing the shores; lake plains and lake deep. The mean depth is 18.55 m, the maximum depth being 25.70 m. The maximum effective width and length are 466.6 m and 1466.6 m respectively. In 1895, the capacity of the lake was 31,699 m3. It bas become drastically reduced to 26,202 m3 by 1979, that is by 5,491 m3 in 84 years. This reduction in the capacity of the lake at the rate of 65.37m3/year is due to the increasing rate of siltation. On the basis of the rate deduced, it is inferred that the lake will be filled completely in about 380 years.
Rare Metal-Bearing Pegmatites in Parts of Southern Karnataka, India
Authors: Banerjee D. C. , Ranganath N. , Maithani P. B. , Jayaram K. M. V.
Published: November 2024

Several pegmatites containing commercially viable sources of columbite-tantalite have been located in the Holenarsipur, Kdshnarajapet and Nagamangala schist belts. The pegmatites in Holenarsipur schist belt near Hassan, contain columbite-tantalite, rich in both niobium and tantalum and carry appreciable amounts of beryl. The Nagamangala schist belt is particularly rich in tantalite-bearing (Ta2O5 50-70%) pegmatites.

Analysis of feldspars from the three different belts indicates that they are potassic in the Nagamangala belt while they are sodic in the case of two other belts. Trace element analysis of muscovite indicates an average of 42, 242, 107, 325 ppm of Be, Nb, Sn and Li in Nagamangala belt as against 55, 114, 127 and 329 ppm respectively in Holenarsipur belt. Presence of considerable amount of bismutite in Mundur pegmatite and traces of spodumene and pollucite in Nagamangala belt have been confirmed.
Petrology of Jutogh Metapelites near Chaur, Himachal Himalaya, India
Authors: Das Brijraj K. , Rastogi R.
Published: November 2024

The Jutogh metasediments in Chaur area have undergone three phases of deformation D1, D2 and D3 respectively, associated with two metamorphic episodes M1 and M2. The M1 episode was synkinematic in relation to the F1 folding phase (D1) and continued postkinematically to F1. reaching its climax during a static phase between D1 and D2. Most of the porphyroblastic minerals such as staurolite, kyanite, sillimanite and even garnet crystallized during this period. The M2 metamorphism superposed M1 during D2 deformation and was of retrograde nature. The isograds have been delineated by specific mineral reactions and the zones are characterised by critical mineral assemblages.

Metamorphic conditions suggest pressure of about 6.0 (±0.5) kb, and temperatures of 540°C (±10°C), 560°C (±10°C), 640°C (±10°C) and 650°C (±10°C) in zones (B) garnet-chlorite, (C) staurolite-biotite, (D) kyanite-biotite and (E) sillimanitegarnet-biotite, respectively.
Petrogenesis of Basalts: Examination of REE Data Using Pattern Recognition Approach Through Principal Component Analysis
Authors: Arunachalam J. , Murali A. V. , Sankar Das M.
Published: November 2024

A pattern recognition (PR) approach based on the principal component analysis (PCA) is adopted for the petrogenesis of basalts using the relative behaviour among the REE, on the data-sets of tholeiites (MOR, ocean island and continental) and alkalic basalts (melilites, nephelinites and alkali olivine basalts). It is observed that the overall variability in the REE data requires two or three principal components; with the first component accounting for 80% of the variability. The coefficient patterns of these components reveal distinct features. The dominant (first) component of tholeiites, exhibits a poor covariance of La and Ce with MREE. Coefficient patterns of the dominant component of tholeiites show breaks at Sm and at Dy/Tb similar to those observed in high pressure partition coefficients for cpx. The coefficient patterns in this major component appear to describe the REE behaviour during partial melting and high pressure fractionation of opx or cpx and eclogite.

In contrast with the tholeiites, the dominant component in alkalic basalts, shows excellent covariance among the LREE and MREE. Among the alkalic basalts, the alkali olivine basalts, show a different HREE behaviour. Comparison of the coefficient patterns of the dominant component of tholeiites and alkalic basalts suggests distinct differences in their source/mechanism of formation.

Theoretical computations involving partial melting and fractional crystallisation of only the major mineral (ol, opx, cpx, garnet/spinel) prove to be inadequate to simulate the observed coefficient patterns. The inclusion of 87Sr/86Sr isotopic ratios along with REE in the PCA, generates 'features' suggestive of additional sources (interstitial liquid, accessory minerals in the mantle and/or granitic crustal contamination) as contributing factors.

The PR approach described in this work allows one to extract more information from the REE data-set than what is possible by simple chondritic normalisation.
Structures and Textures of Vanadium-Bearing Titaniferous Magnetite Ores and their Interpretation
Authors: Chakraborty K. L. , Roy Jishu , Majumder Tapan
Published: November 2024

Various types of exsolution and replacement structures and textures uf the vanadium-bearing titano-magnetite ores have been described from the titano-magnetite deposits occurring in the gabbro-anorthosite complexes of Orissa, India. Attempt has been made to correlate different textures to various oxidation stages. The ores were formed within the temperature range of 600°-800°C and average fO2 = 18.4.
Geology of Greywackes West of Ranibennur, Dharwad District, Karnataka State
Authors: Chavadi V. C. , Hegde V. S.
Published: November 2024

The greywackes of Ranibennur are granodioritic in composition, and have been deposited in eugeosynclinal basin under reducing conditions. Matrix of the greywackes indicates operation of more than one process for its origin.
Silica Bead Industry in Cambay, Gujarat State, India
Authors: Karanth R. V.
Published: November 2024

Silica bead manufacturing industry in Cambay has a tradition of more than two thousand years. Even today it forms an important cottage industry in Gujarat. With the indigenously developed age-old methods of bead making, this industry here is successfully competing with other bead industry centres in the world. Only recently mechanised grinding and tumbling processes have been adopted. However, the concept of tumbling is not entirely alien to this cottage industry, because some forms of manunl tumbling were in practice in earlier years.
Foraminifera from Shore Sands of Bhatkal and Devgad Islands, West Coast of India
Authors: Shareef Nayaz Ahmed , Venkatachalapathy V.
Published: November 2024

Investigation of foraminiferal microfauna of the shore sands of Bhatkal and Devgad islands (Karnataka) , west coast of India, has facilitated recognition of 40 species from Bhatkal and 41 species from Devgad islands. A check list and illustrations for the species identified are provided. Three species are recorded for the first time from Indian waters. Based on population characteristics and distributional pattern, depositional environment and Indo-Pacific affinities of the microfauna are elucidated.
Monitoring Landslides in Dihang and Subansiri River Basins, Arunachal Pradesh
Authors: Prakash P. , Parthasaradhi E. V. R.
Published: November 2024

A study of aerial photographs taken before and immediately after the Great Assam Earthquake of 15th August 1950 revealed that the event had caused extensive landsliding in the northeastern India, including parts of catchments of Dihang and Subansiri rivers. Examination of the photographs of the same areas taken during 1959-60 and 1976-77 showed, that majority of the slopes that failed as a result of the earthquake, got stabilised to a large extent and some fresh landslides occurred during the period in a few areas.

Air-photo study shows that (i) the highly jointed nature of the Miri Quartzite has contributed to the maximum incidence of landslides in any particular lithological unit. (ii) The Main Boundary Fault and the system of faults parallel to it, in the Subansiri catchment have been reactivated during the Assam earthquake. (iii) In Dihang catchment, the MBF, and the Siang fracture have been reactivated.

In view of the possibility of fluid pressure exerted by impounding large quantities of water triggering off a major earthquake, it is suggested that construction of very large dams be avoided, even though the region has a very high hydel power potential.
Trace Fossils from Cambrian Tal Formation, Himachal Lesser Himalaya, India, and their Stratigraphic Significance
Authors: Mathur V. K. , Joshi Ashutosh , Kumar Gopendra
Published: November 2024

Two assemblages of ichnofossils are recorded from the Cambrian Tal Formation, Nigalidhar Syncline, Himachal Lesser Himalaya. The assemblage-I. occurring in the Arenaceous Member 300m below the horizon yielding redlichiid trilobite and brachiopod faunas of Tsanglangpuian Stage of Early Cambrian, contains forms like Rusophycus sp. aff. R. carinata Seilacher, monomorphichnus lineatus Crimes, Diplichnites spp.) Gordia sp., Astropolichon sp., ichnogenus A and ichnogenus B. The assemblage-II, in the Phulchatti Member ('Upper Tal'), includes Cruziana sp. and ichnogenus C cf. Buthotrephis. It occurs in sediments 70 m above the horizon containing trilobites and brachiopods. The former assemblage is of world-wide distribution in Lower Cambrian (upper Meishucunian to Lower Qiongzhusian), and thus, in the absence of microfauna, can be utilised in identifying Early Cambrian successions.
Morpho-Chemistry of Rutile in Dengura Manganese Ore Bodies of Koira Valley, Orissa
Authors: Mohapatra B. K. , Natarajan R. , Paul A. K. , Sahoo R. K.
Published: November 2024

Minute discrete grains of rutile present in manganese ores of Dengura, Koira valley, Sundergarh district, exhibit imperfect columnar and crystallographic forms and an outstanding illustration of twinning. EPMA and EDAX results indicate the presence of Fe, Mn, Cr, Al, Ba, K and Ta, Nb in minor proportion, in rutile crystals. Some of these clements are either present in limited solid solution or later got introduced into its structure during late epigenetic processes. These are detrital grains, pre-existing in the host shale and later affected by solution during epigene manganese are formation.
The Conglomerates of Holenarasipur Schist Belt and the Nature of Pre-Holenarasipur Crust of Peninsular India
Authors: Hussain S. M. , Naqvi S. M.
Published: November 2024

Two types of conglomerates occur in the Holenarasipur schist belt. The Tattekere conglomerate occurring in the older horizon (>3.4 b.y.) ofthe belt is oligomictic and is tectogenic (autoclastic), devoid of pebbles of detrital sedimentary origin. The Gopalapura conglomerate occurring in the younger horizon (3.2 to 3.0 b.y.) of the belt is, on the other hand, polymictic and sedimentogenic. Occurrence of gneiss pebbles in this conglomerate indicates presence of gneissic terrain in the source area and strongly supports the view that considerable sialic crust had evolved before the younger greenschist sequences were deposited in this region. This extensive crust is formed by widespread emplacement of acidic plutons during the time gap between the older and younger sequences of Holenarasipur. It is proposed that older Holenarasipur schists and gneisses which intruded it supplied the debris to the younger belt.
Petrochemistry of Basics and Metabasics, Mandi-Pandoh Area, Himachal Pradesh, India
Authors: Gupta L. N. , Chaudhri Naveen , Prasad A. K.
Published: November 2024

Basic and metabasic rocks occur in the form of an oval-shaped, plug-like body. intrusive into the granitic gneisses and metasediments belonging to the Chail Formation. The core is made of fresh olivine gabbro metamorphosed to varying degrees at the margins. Chemical data suggest that the basic and metabasic rocks are co-magmatic and the parent magma was of alkali olivine basalt composition. The observed diversity in physical and textural parameters exhibited by different rocks are considered to be the expressions of varying rates of cooling and effects of autometamorphism. These are more pronounced at the margins than in the central parts of the body.
Water and Sediment Load in Streams Draining Mussoorie Phosphate Mining Areas
Authors: Singh B. K. , Subramanian V.
Published: November 2024

Water quality studies in the mining areas clearly point out to the contributions made by the mining activity to the chemical composition of Bandal flver in the Durmala and Maldeota region Levels of phosphates and fluofide in the water are enhanced even in canal waters in the Debra Dun region Drinking water in some taps in Doon valley also show higher levels of contammation for F and P The Bandal fiver carnes total dissolved solids of about 550 ppm which is much higher than the average Indian and world river waters Throughout the region all surface waters are supersaturated With respect to fluorapatite, hydroxyapatite and carbonate apatite. In reality, this equilibrium assembly is not reflected in the phosphate minerals present In tbe river sediments Phosphate minerals constitute nearly half the population of the alluvial sediments in the region with pockets of pyrite minerals up to 10% of the sediments by weight Trace elements like Cu, Cr and F show good Correlation with the P content in the sediment suggesting common sites within the sedlment grains.
Stratigraphy and Structure of Late Archaean, Dharwar Volcanic and Sedimentary Rocks and their Basement in a Part of the Shimoga Basin, East of Bhadravathi, Karnataka
Authors: Chadwick B. , Vasudev V. N. , Jayaram S.
Published: November 2024

The Dharwar Supergroup in the Shimoga basin east of Bhadravathi has been subdivided into seven formations on the basis of sedimentary structures and facies. The lowest is dominated by metabasites including metalavas and tuffs, metagabbros with seams of titaniferous magnetite, serpentinites and talc schists. A range of sedimentary rocks including phyllitic greywackes, quartzites, dolomitic limestones, conglomerates and local banded ferruginous cherts characterise the formations overlying the metabasites. These formations include local metabasites, and the youngest formation contains a thick suite of metarhyolites. The Dharwar lithostratigraphy is characterised by rapid lateral variations in thickness and facies which are the consequence of its original unstable alluvial and relatively shallow marine depositional environments. The instability is marked by slump structures in the phyllitic greywackes and by debris flows at many levels in the stratigraphy. The Dharwar rocks were deposited on a basement of homogeneous granodiorite s.l. and foliated multiphase quartzo-feldspathic orthogneisses. Erosion of elevated parts of the basement and the Dharwar cover provided detritus for alluvial fans, shallow marine quartzites and more distal phyllitic greywackes. Correlation of the lowest formations in tbe Bababudan basin immediately to the south shows that the Dharwar Supergroup becomes progressively younger from south to north in this part of Karnataka.

The structure is characterised by large upright synclines in the Dharwar cover with intervening domal areas of basement. Many of the cover-basement contacts are faults, but some are interpreted as rotated and steepened unconformities. Flushing of water and CO2 through much of the basement and cover took place during deformation. Buoyancy forces related to heating at deep crustal levels and concomitant compressional forces, generated perhaps in a transpressive oblique-slip regime, may account for the structure of the cover and its basement. Comparable tectonothermal instability, but with trans-tensile components, may have characterised the Dharwar volcanic and depositional phases.
A Comparative Study of Transmissivity Values Obtained by Slug-Test and Pump-Tests
Authors: Karanth K. R. , Prakash V. S.
Published: November 2024

The paper deals with the comparative study of the transmissivity values obtained by slug-tests and pump-tests on 58 wells drilled by DTH rigs in crystalline rocks comprising granites, gneisses, schists and basalts. The present study indicates that transmissivity values obtained by two methods vary mostly within a factor of three, except for pump-test T values of less than 10m2/day.
History of Successive Deformations in Relation to Metamorphism-Migmatitic Events in the Schirmacher Hills, Queen Maud Land, East Antarctica
Authors: Sengupta Sudipta
Published: November 2024

The basement complex in the Schirmacher Hills of East Antarctica records the impress of multiple episodes of metamorphism, migmatization and deformation. In the earliest event there was a regional metamorphism under granulite facies conditions and synkinematic migmatization leading to the development of charnockitic rocks. An amphibolite facies metamorphism was superimposed on them. This late event was closely associated with widespread granitization leading to the development of the majority of the quartzofeldspathic gneisses. In the earliest deformation, a migmatitic banding and a crude foliation formed in the charnockitic rocks. This was followed by a period of strong deformation during which two broadly coaxial sets of isoclinal folds (F2A and F2B) formed. The folding movement was also associated with widespread ductile shearing. The periods of amphibolite facies metamorphism, extensive granitization, F2 folding and the major phase of ductile shearing were overlapping. Localized pegmatite bodies were also emplaced during the later and much weaker folding movements of F3 and F4 and along some discordant ductile shear zones cutting across the axial surfaces of F2 folds.
Ecologic Distribution of Planktonic Foraminifera in the Bottom Sediments of the Northwestern Part of the Bay of Bengal
Authors: Pal Elonee
Published: November 2024

Ecologic distribution of the four abundant species of Planktonic foraminifera Globigerina bulloides, Globigerinoides rubra, Globigerinoides triloba and Neogloboquadrina dutertrei from the bottom sediments are described. The mode of analysis of distribution pattern followed can be used effectively for determining the paleoenvironment of ancient shelf area which bordered the mainland and whose physical environmental conditions were controlled by large river systems.
Analysis of the Gravity Field Over Parts of South Singhbhum, Sukinda Ultramafic Complex and Nature of Sukinda Thrust
Authors: Verma R. K. , Mukhopadhyay M. , Subba Rao P. B. V. , Satyanarayana Y.
Published: November 2024

A regional gravity survey has been carried out over the area lying between latitude 20°30' to 21°30'N, and longitude 85° to 86°15'E, forming a part of south Singhbhum geological province and northern part of the Eastern Ghats. The area is well-known for Sukinda ultramafic complex, Diateri and Malayagiri iron-ore deposits as well as Sukinda thrust.

Nearly 350 gravity stations were established along main roads, forest roads and cart tracks. Bouguer anomaly map of the area shows gravity highs over the Diated iron-ore group, the Malayagiri volcanics, the Sukinda ultramafic complex as well as over the Eastern Ghats province. Two-dimensional models. have been prepared to show the nature of the ultramafic complex, iron-ore group (lOG) of rocks and the Sukinda thrust. The lOG appear to form narrow but steeply dipping sedimentary troughs, while the Sukinda thrust appears to be steeply dipping to the south.
Cretaceous-Tertiary Boundary Events: The Fossil Vertebrate, Palaeomagnetic and Radiometric Evidence from Peninsular India
Authors: Sahni Ashok , Bajpai Sunil
Published: November 2024

Recent data based on microvertebrates and associated microfossils suggest that the Lameta and coeval formations of Peninsular India are younger (Maestrichtian) than ages previously assigned to them (Cenomanian-Turonian). Similarly, the Takli and their intertrappean correlatives in several localities have yielded dinosaurian elements indicating thereby a Cretaceous rather than Tertiary age. Furthermore, no exclusively Tertiary taxa has been recorded from these beds at Nagpur, Asifabad, Kachchh and adjoining areas. Samples collected for palaeomagnetic studies with reference to vertebrate-bearing horizons suggest that the Deccan basaltic activity was initiated in the Late Maestrichtian at the end of Lameta times. The major part of the eruption took place during the reversed magnetic chron, 29R, which encompasses the Cretaceous-Tertiary Boundary. Radiometric dates (K/Ar, 40Ar/39Ar) tend to cluster in a 60 m.y. 70 m.y. interval. The Deccan traps have been cited as a possible alternative source of Ir enrichment in comparison to the hypothesis which ascribes the anomalously high values of this element at the KTB to an extra-terrestrial impact. The gradual decline of dinosaurs as well as other marine plankton and benthos towards the close of the Cretaceous favours hypotheses that do not advocate 'instantaneous' global mass extinctions.
The Effect of Conrad on Regional Gravity Interpretations
Authors: Ramakrishna T. S.
Published: November 2024

When the regional Bouguer gravity anomalies do not corroborate with the surface geology, the general tendency of many interpreters is to take recourse to the undulations in the Moho, ignoring the Conrad in between, inspite of the fact that Conrad has been traced in several parts of the country by DSS as well as by gravity. Further, while inferring basic intrusives to explain some of the gravity highs, the corresponding magnetic data is also not taken into account. This note shows how Conrad may be creating disorder in regional gravity interpretations and how ignoring magnetic data leads to weak and suspect inferences.
Geometrical Analysis of Two Dimensional and Three Dimensional Oscillation Ripples
Authors: Das Subhasish
Published: November 2024

Analysis of ripple geometries using known tabulated laboratory and field data shows that the geometry can be of three types, i.e., sand ripples, light sediment ripples, and oscillatory bed ripples, reflecting different effects of the fluid shear stress and fluid accleration on the bed sediments. It is shown that when the bed shear stress or the amplitude of the water particle relative to the sediment size is small, the resulting vortices are more regular with low turbulence intensity and the generated ripples are two dimensional. However when the bed shear stress is large, the resulting vortices are very irregular with high turbulence intensity and the generated ripples are three dimensional in character.
Foraminiferal Evidence for Sediments of Santonian Age Occurring on Baratang Island, Andaman, India
Authors: Rajshekhar C.
Published: November 2024

The paper incorporates systematic descriptions of ten planktonic foraminiferal species recovered from the ejected material of mud volcanoes active on the Baratang Island, Andaman. The species are Pseudotextularia browni Masters, P. carseyae (Plummer, Globotruncana aegyptiaca Nakkady, G. arca (Cushman), G. concavata (Brotzen), G. coronata (Bolli), G. fornicata Plummer, G. gansseri Bolli, G. renzi Gandolfi and G. schneegansi Sigal.

Appearance of Rugoglobigerina rugosa, Ventilabrella glabrata, Globotruncana concavata and simultaneous extinction of G. schneegansi indicate Santonian as a lower age limit of Cretaceous rocks on the Baratang Island.
Upper Cretaceous Dinosaur Eggs from New Localities of Gujarat, India
Authors: Mohabey D. M. , Mathur U. B.
Published: November 2024

New occurrences of well-preserved dinosaur eggs have been found in the Lameta sediments near Dohad in Panchmahals district, Gujarat. The new localities lie 90 km east of the well-known Balasinor-Rahioli belt, which has the distinction of being one of the few dinosaur nesting sites in the world. The dinosaur eggs are spherical and have nodose ornamentation. Two types of egg shells have been distinguished on the basis of their microstructure. The egg shelIs have affinity towards sauropod types and are comparable to those of Kheda Type-B.
Tectono-Stratigraphy and Emplacement History of the Ophiolite Assemblage from the Naga Hills and Andaman Island-Arc, India
Authors: Acharyya S. K. , Ray K. K. , Roy D. K.
Published: November 2024

The oceanic pelagic sediments from the ophiolite assemblages of Naga Hills (NHO) and Andaman islands (ANO) broadly correspond to Late Cretaneous to Paleocene age. Late Cretaceous ocean floor represented in ANO was dominantly below the carbonate-compensation-depth (CCD), whereas it was uneven but mainly above CCD during Paleocene-Early Eocene. Maestrichtian to Paleocene ocean floor appears to be dominantly above the CCD in NHO. The NHO and ANO have closely similar postemplacement ophiolite-derived mid- and mid-late Eocene cover sediments respectively. Emplacement of the Naga Hills ophiolites during mid-Eocene, was possibly caused due to initial collision of an ocean-island chain with the subduction zone beneath the Central Burmese continent. Emplacement of the Andaman ophiolites occurred during early-mid-Eocene and may have been caused by a similar situation. The Chin Hills ophiolites were also mainly emplaced during early Eocene. The accreted ophiolites of the Indo-Burman range and Andaman islands were thrust westward over the Paleogene turbidite pile, deposited on the down going Indian plate during late Oligocene, due to terminal India-Burma continent-continent collision. In the southern Manipur sector of Naga Hills, the olistostromal upper Disang Formation (mid to late mid-Eocene) tectonically flooring the NHO, stratigraphically underlies the flyschoid to molassic Barail (Oligocene) sediments. In Andaman islands, the Lipa Formation with early Eocene and older olistoliths, forms the dominant constituent of the lower tectonic sedimentary melange flooring the ophiolites. Towards west, the sedimentary melange overrides the Archipelago Group. (Neogene) which unconformably overlies the Andarnan Flysch of Eocene-Oligocene age. The root-zone of the collisional suture appears to be concealed below younger sediments in the Central Burma basin and in the Andaman Sea, parts of the latter being created as a back-arc marginal basin. There is thus no straightforward relation between the Late Oligocene collision suture and the present subduction zone along the trench to the west of Andaman-Nicobar islands.
Geochemical Characteristics of Mudbank Environment - A Case Study from Quilandy, West Coast of India
Authors: Ramachandran K. K.
Published: November 2024

Aerial variatron of SiO2, Al2O3, MgO, CaO, TiO2, K2O and Na2O in the Mudbank sediments off Quilandy are discussed. A comparative study of textural classes versus the elemental concentration revealed a size dependence factor on the elemental speciation. Chemical variability depicted from cluster analysis suggests three interrelated elemental groups, such as (I) Al2O3, Fe2O3, Na2O and MgO probably controlled by hydrous aluminosilicates in the finer fractions, (2) TiO2, CaO and SiO2 with coarser materials especially CaO with shell fragments, (3) lone element K2O influenced by both hydrous aluminosilicates and feldspars.

Mudbanks are conspicuous with high load suspension. Initial triggering which brought the sediments into suspension is explained in terms of convulsive physical action during the onset of southwest monsoon. It has been found that mudbank sediments are enriched with alumina and ferric oxide. Salinity reduction in the nearshore waters due to monsoonal precipitation is an ideal condition (optimum electrolitic concentration) to defloculate and disperse the sediments into suspension in the presence of phosphate as a natural peptizer. Hence apart from the physical mechanism of suspension, dispersion as a chemical mechanism for the sustenance of suspension is suggested.
How old are the Old Mine Workings of Ingaldhal (Karnataka) ?
Authors: Shankar R.
Published: November 2024

Two 14C dates (2070 ± 110 years B.P. and 1820 ± 100 years B.P.) on wooden logs which were used as supports in old workings of lngaldhal copper mines are reported here. These dates are discussed in a historical/archaeological perspective.
On Applying the Concept of Rupture Propagation to Deduce the Location of the 1905 Kangra Earthquake Epicentre
Authors: Chander Ramesh
Published: November 2024

Richter estimated from analyses of P arrival times on available seismograms that the epicentre of the 1905 Kangra earthquake lay on the border of Jammu-Kashmir and Himachal Pradesh, approximately 100krn north of Kangra. This point lies far outside the limits of rupture deduced from analyses of macroseismic effects of the earthquake. We apply the concept of rupture propagation to suggest that the Kangra earthquake epicentre was in the southeastern part of the mcsoseismal area in the Chakraia-Mussoorie sector of the Lesser Himalaya near 31° N, 78° E.
On the Occurrence of Rugoglobigerina, Species in the Borehole (577M to 585 M) at Ambalapuzha, Alleppey District, Kerala
Authors: Rajendran C. P.
Published: November 2024

Planktonic foraminifera comparable to Rugoglobigerinarugosa encountered in the sediments occurring at a depth, ranging from 577 metres to 585 metres in a borehole at Ambalapuzha in the coastal district of Alleppey in Kerala is reported. Significance of these foraminifera present in the bottom most part of the onshore sedimentary basin of Kerala is briefly discussed.