bluuebunny/crossref_metadata_2025_split huggingface dataset:
Almandine-Rich Garnets from Payalite-Perrosilite- Quartz-Bearing Ferrosyenites in the Prakasam District of Andhra Pradesh, India
Authors: Leelanandam C. 
Published: November 2024

Abstract
The fayalite-bearing ferrosyenites in the Prakasam district of Andhra Pradesh are distinctly unique as they strangely contain not only the ferrosilitic orthopyroxene but also Iate aIrnandine-rich garnet, the two minerals which are totally alien to similar rocks occurring elsewhere in the world. Symplectic, vermicular, granular and coronal garnet (with intergrowth of quartz) occurs in insignificant amounts with sporadic distribution around ore, orthopyroxene, clinopyroxene, hornblende and fayalitic olivine when they are in contact with feldspar (occasionally with intervening and incomplete rim of quartz), All the garnet-forming reactions might have resulted due to falling temperature. High and variable silica activity, local variations in f02 and rate of cooling may explain many of the observed textural features.
The electron microprobe analyses of almandine-rich garnets suggest two independent substitutions have taken place, one involving Ca and Mn, and the other involving (Ca+Mn) and Fe. The minor chemical variations in garnet are significantly controlled by its habit. Textural features, and inter- and intra-granular compositional variations in garnet even within a single specimen reflect its disequilibrium formation.
Geology and Hydrocarbon Prospects of East Coast Sedimentary Basins of India with Special Reference to Krishna Godavari Basin
Authors: Rao G. N. 
Published: November 2024

Abstract
The Eastern continental margin of the Indian Peninsula has a complex geoiogical history. Due to fragmentation of Gondwanaland the Peninsula was separated and became the mobile Indian plate. The ' Godavari bend ' of the East coast coincides with triple junction of the diverging plates. Palaeozoic to Early Mesozoic sedimentation in the East coast basins is of continental nature and is restricted to rift grabens. The easterly tilt of the Peninsula during its movemtnt gave rise to peri-cratonic sedimentary basins since the Cretaceous. These basins are extended oceanic basins with subsided pull-apart basins. Since Miocene, the cooling of the oceanic crust has facilitated more sedimentation in these basins. Basin configuration, tectonics and status of hydrocarbon exploration are discussed basinwise giving more emphasis to Krishna- Godavari Basin.
Stratigraphie Position of the Tirodi Gneiss in the Precalnbrian Terrane of Central India: Evidence from the Mansar Area, Nagpur District, Maharashtra
Authors: Mohanty S. 
Published: November 2024

Abstract
In the Precambrian terrane of central India the question of the relation between different gneiss and schist belts has not been solved. Eventhough the Tirodi gneiss is generally considered to be the basement of the Sausar Group, unequivocal sedimentological criteria are not supplemented to confirm this view. A conglomerate which belongs to the Sausar Group has been mapped at the contact of a gneissic roc in the Mansar area of Nagpur district, Maharashtra, during the present investigation. Occurrence of gneiss pebbles in this conglomerate suggests that the gneissic unit was the source of the pebbles and acted as the basement to the Sausar Group.
Electro-Facies Analysis of Reservior Rocks of Krishna-Godavari Basin
Authors: Rao G. N. 
Published: November 2024

Abstract
Recent advances in electric logs make it possible to record the logs at very thin sampling interval. The natural radiation of rocks (gamma rays) can be analysed while recording itself into three basic components like K40, Th232, and U238. The electro-facies analysis can be used to interpret the nature of sedimentary environments. The interpretation techniques for identifying the nature of different sedimentary environents arc discussed with suitable examples of electric logs from Krishna-Godavari basin. Fracture identification procedure in case of basalts and extension direction of Paleogene reservoir sands are discussed. NGS ratio log can be used in identifying the debalable age boundaries.
Tectonic Evolution of the Almora Crystalline Zone, Kumaun Lesser Himalaya: A Reinterpretation
Authors: Agarwal K. K. 
Published: November 2024

Abstract
The Almora Crystalline zone (ACZ) is one of the largest and better studied crystalline outcrop of the Lesser Himalaya. The paper presents a reinterpretation of its tectonic evolution in the light of new data generated in the course of the present study. Presence of mylonite zones (of variable thickness), bordering, as well as within the crystallines, indicate the possibility of branched-up small duplexes, from a common 'sole thrust'. Analysis of small folds and other minor structures. especially the stretching lineations and small scale shear zones indicilte a N-NNE to S-SSW direction of tectonic transport. The very synformal nature of the ACZ has been doubted here in the light of our recent understanding on rock deformation and thrust sheet movement with reference to the Himalaya. A new model has thus been presented here, according to which the ACZ represents only a small portion of a large thrust sheet which was once covering,the whole of the Lesser Himalaya. The synformal nature of the ACZ is probably due to back-thrusting in the later phases of its tectonic development.
Joint Analysis Around Nauti, District Chamoli, U.P.
Authors: Singh R. A. , Gairola Y. K. 
Published: November 2024

Abstract
The orientation of joints were measured in the massive quartzites and metabasites of Garhwal Group around Nauti, District Chamoli, U.P. The area has been divided into six sub-areas for the dynamic analysis. Three joint sets have been inferred in the area on the basis of 10 å-sector rose diagrams. These joint sets exhibit a mean strike of NW-SE, NNE-SSW and N80°E-S80°W respectively, with a variation of 5° to 10° in different subareas. Of these only the first set of joints is common in all the subareas, whereas other two sets occur in different subareas. This difference in the orientation of joints in different subareas has been attributed to the rotation of rocks and development of new joints during subseguent deformations. The analysis of joints reveals that they were mainly developed during the second phase of deformation, whereas in the third and Fourth phases of deformations during the Himalayan orogenic movements earlier joints were reactivated and reoriented, as well as new joints were also developed.
Elemental Composition and Particulate Metal Fluxes from Netravati and Gurpur Rivers to the Coastal Arabian Sea
Authors: Shankar R. , Manjunatha B. R. 
Published: November 2024

Abstract
Physico-chemical parameters of water (pH, dissolved oxygen, salinity and suspended Particulate concentration) and geochemistry (Cu, Pb, Zn, Ni, Co, Mn, Fe, Al, Ca and organic matter) and magnetic susceptibility of suspended particulates have been measured, incidentally for the first rime. in two west-flowing rivers - Netravati and Gurpur - of southwestern India in order to understand weathering processes, to determine gross particulate metal fluxes to the coastal Arabian Sea and to decipher anthropogenic influences, if any. Physico-chemical parameters do not show significant variations because of the heavy fresh water discharge during southwest monsoon. The composition of Netravati and Gurpur rivers SPM (suspended particulate matter) are similar and characterized by enrichment of Al, Fe, Ni and Co but strong depletion of Ca in comparison with temperate and major rivers of the world. This is an imprint of the intense chemical weathering in the study area. Copper, Pb, Zn and Mn contents in Netravati and Gurpur R. SPM are lower than world river SPM, implying that there may not be significant anthropogenic input of these metals.
The gross particulate metal fluxes from the Netravati R. are considerably higher than those in Gurpur R, because of the former's high sediment discharge. However, the fluxes are significantly lower than those of Narbada and Tapti rivers.
Magnetic susceptibility of Netravati and Gurpur SPM is nearly the same, but substantially low (by a factor of three) when compared to the silt+clay fraction of river-bed sediments, indicating that dense magnetic minerals are not transported in suspension but as bed-load.
Mineralogy and Geochemistry of Chigicherla Kimberlite and its Xenoliths, Anantapur District, South India
Authors: Murthy D. S. N. , Dayal A. M. , Natarajan R. 
Published: November 2024

Abstract
Petrography and chemistry of newly discovered Chigicherla Kimberlite pipe of Andhra Pradesh, South India are presented. The textural characteristics of the rock suggest it to be more close to the hypabyssal type of kimberlite. Presence of melilite classifies these rocks as extreme variety of kimberlite. Mineralogy of the spinel harzburgite xenoliths that occur within these IGmberlite reveals two types of xenoliths:
Harzburgite xenoliths having spinel which is Cr rich (61.6%) and Al (10.29%) poor. Harzburgite xenolith having spinel which is A1 rich (4358%) and Cr (25.90%) poor.
Temperature estimates reveal that the Cr-rich type xenolith has equilibrated at 972°C while the Cr-poor ones were equilibrated at 839°C ± 31°C. The maximum pressure estimated for these xenoliths is 25 kb. Presence of chrome spinel and absence of magnesium aluminium spinel in the xenoliths, indicate that the uppermost 45 or 50 km of the mantle section has highly "depleted" peridotite composition. The study supports the contention of the steady state of thermal condition in the mantle lithosphere beneath the continental shield and has not changed appreciably through the last one billion years.
Radiometric, Magnetic Susceptibility and Mineralogical Studies in Some Beach Placers of Andhra Pradesh, East Coast of India
Authors: Nagamalleswara Rao B. 
Published: November 2024

Abstract
Radiometric, magnetic susceptibility and mineralogical studies were carried out on the beach placer deposits in three different coastal regions of Andhra Pradesh: Hamsaladivi-Manginipudi (Region I), Vasishta Godavari-Upputeru (Region II) and Visakhapatnam-Bheemunipatnam (Region III). Radioactivity is highest in Region III and Iowestin Region I. Zircon being non-radioactive and other radioactive minerals being rare or absent; monazite is the only source of radioactivity in the three regions. Ilmenite is predominant in Region III and magnetite in Region I. Higher concentration of monazite is associated with ilmenite and not with magnetite. The Eastern Ghats provenance is the major source of ilmenite and monazite. It is suggested that pospecting for monazite and ilmenite in East Coast of India beaches is best done by a combination of radiometric and magnetic susceptibility techniques.
Occurrence of Spodumene in the Rare Metal-Bearing Pegmatites of Mariagalla-Allapatna Area, Mandya Dist., Karnataka
Authors: Banerjee D. C. , Krishna K. V. G. , Murthy G. V. G. K. , Srivastava S. K. , Sinha R. P. 
Published: November 2024

Abstract
Spodumene bearing rare metal pegmatites are reported mostly from Karnataka in contrast to lepidolite and amblygonite bearing pegmatites described from major mica-fields of India. Tantalite (Ta2O5 50-70%) rich pegmatites intruding the Sargur metasediments of Nagamangala schist belt near Marlagalla- Allapatna are also rich in spodumene (10-15% by vol.) as well as beryl (10.6-11.4% BeO). Light green spodumene (Li2O 6.55-7.35%) occurs randomly as prismatic crystals a few cm to 30 cm in length. Under the microscope, symplectic intergrowth between spodumene and quartz along the contact with albite and replacement of spodumene by quartz and muscovite are noticed. The 'd' spacings and intensities obtained from the X-ray diffraction patterns match well with the published values for Alphaspodumene from Pala San Diego County, California, U.S.A. Some variations observed in the intensities ofinterplanar spacings could be due to preferred orientations exhibited by the mineral. When heated to 1000° C for 3 hours, the Alpha-spodumene transformed to Beta- spodumene.
Chemically these spodumenes are "high iron non-chromian" types (FeO+Fe2O3 1.17 to 1.29%, Cr47- 87 ppm). While Mn content is high (1237-1826 ppm), other trace elements such as V, Cu, Co, Pb and Be are less than 10 ppm, Cs 39-98 ppm and Sn 19-28 ppm. Sn values are considerably low as compared to specimens reported from elsewhere, possibly because these pagmatites are devoid of cassiterite. Mineralogical assemeblage ofspodumene-tnntalite-pollucite in these pegmatites places them in "LCT (Lithium-Caesium-Tantalum) family" of rare element pegmatites as per classification of Cerny. Petromineralogical and geochronological studies of Allapatna granites have been undertaken which will throw furthur light on the geochemistry and paragenesis of these pagmatites. Few hundred tonnes of spodumene are expected to be recovered commercially from shallow depths alone along with tantalites and beryl.
Pellatispira crassicolumnata from Kachchh, Gujarat
Authors: Ray Anis Kumar , Chaki Tapasri 
Published: November 2024

Abstract
Late Eocene foraminifera genus and species Pellatispira crassicolumnata Umbgrove is documented from Kachchh (Kutch) as an unequivocal evidence of the presence of rocks of that age in the basin. The same species has earlier been reported from Surat-Broach, Gujarat and its Kachchh occurrence suggests the then existence of a trail of similar environments in this part of land.
Metamorphic-Metasomatic Fluids and Al, Si Order/Disorder of K-Rich Alkali Feldspars from Southern Indian High Grade Terrain
Authors: Swamy V. , Anantha Iyer G. V. , Menon A. G. 
Published: November 2024

Abstract
The structural state of K-feldspars in the quartzofeldspathic gneisses, charnockites, metapelites and pegmatites from the southern Karnataka, northern Tamil Nadu and southern Kerala high-grade regions of southern India has been characterized using petrographic and powder X-ray diffraction methods. The observed distribution pattern of structural state with a preponderance of disordered K-feldspar polymorphs in granulites compared to the ordered microclines in the amphibolite facies rocks is interpreted to reflect principally the varying H2O contents in the metamorphic-metasomatic fluids across metamorphic grade. The K-feldspars in the pegmatites of granitic derivation and in a pegmatite of inferred metamorphic origin also point to the important role of aqueous fluids in their structural state.
Late Quaternary Movements and Landscape Rejuvenation in Southeastern Karnataka and Adjoining Tamil Nadu in Southern Indian Shield
Authors: Valdiya K. S. 
Published: November 2024

Abstract
Late Quaternary movements on N-S trending segmented faults in the Southern Indian Shield have given rise to en echelon linear hills and isolated hillocks that abruptly rise 300 to 400m above the 900 m Bangalore peneplain covered thickly with red soil, and are made up of remarkably fresh Precambrian rocks devoid of soil capping. Tilting of soil-covered regolith on the fault-delimited hill flanks together with extraordinarily severe gully erosion in the confines of narrow fault zones bear testimony to continuing movements on these active faults, which also gave rise to many tectonic lakes following stream ponding. Further south, &gt; 1800 m high Biligirirangan-Mahadeswaramalai Hills represent fault-lined horsts, drained by meandering streams that fall and cascade down their steep scarps. Folding of Recent fluvial gravel, development of spectacular knee bend in an otherwise very straight fault valley, and abrupt pronounced northward shift of the Kaveri River from its original southeasterly course indicate Holocene movements on the faults delimiting the horsts.
The &gt;2500 m high Nilgiri massif amidst the 300-150 m Tirupattur-Coimbatore plain is characterized by gently undulating top with very thick soil cover and lazily flowing streams that drop down precipitous scarps (of 1800 to 2000 m sheer fall) through chasms and gorges. Ponding of streams due to reactivation of faults gave rise to lakes comprising 20,000 to 5000 year-old peat within black clays. Thrusting up of the Nilgiri block on the E-W oriented Moyar Shear Zone (which separates the Southern Granulite Terrane from the Dharwar Craton) is a continuing phenomenon, as evident from spectacular rejuvenation of meandering streams, development of multitudes of deep defiles and waterfalls, presence of unfurrowed straight planar valley slopes, and recurrent seismicity in the Moyar Shear Zone.
The thrust movements on the E-W shear zones have been, and are being transmitted northwards as strike-slip and oblique-slip movements on the N-S trending faults in the Dharwar Craton. Close association of epicentres with the fault zones implies that the strain accumulated in the Peninsular Shield is being relaxed through reactivation of these active faults of Precambrian antiquity.
The 24th March, 1995 Chamba Earthquake (NW Himalaya), Field Observations and Seismotectonics
Authors: Mahajan A. K. 
Published: November 2024

Abstract
On 24th March, 1995 at 17:22 hr. IST (11:52 UTC) an earthquake of magnitude 4.9 mb (USGS) struck the Chamba region in northwest Himalaya. The epicentral zone lies 8-10 km northeast of Chamba township. Based on the isoseist characteristics, the source mechanism of this earthquake has been evaluated. The longest axis of the isoseismal is aligned in NW-SE direction, which is parallel to the trend of strike of rocks in the area. The pattern of isoseismals suggest that the causative fault for the 1995 Chamba earthquake is parallel to the local Himalayan trends and the strain has been released at a very shallow depth.
Isotopic Evidence of a Rapid Cooling and Continuous Sedimentation across the Eocene Oligocene Boundary of Wagapadhar and Waior, Kutch
Authors: Sarangi S. , Sarkar A. , Bhattacharya S. K. , Ray A. K. 
Published: November 2024

Abstract
High resolution oxygen isotope analysis of samples from two different Eocene Oligocene Boundary (EOB) sections of Wagapadhar and Waior of Kutch area and their correlation with DSDP sites indicate continuity of sedimentation at these sites. A rapid cooling of -6°C across the EOB, synchronous with extinction of Eocene larger benthic foraminifera, is also observed.
Albitite-Trondhjemite-A-Type Granite Association in the Prakasam Alkaline Province, Andhra Pradesh
Authors: Sarvothaman H. , Srinivasan K. N. , Suresh G. 
Published: November 2024

Abstract
Two dykes of albitite intruding a trondhjemite-A-type granite suite in the Prakasam alkaline province in Andhra Pradesh contain &gt;90% modal plagioclase (albite), and accessory quantities of hornblende, apatite, sphene, anatase and opaque ores. The normative 100 Ab/(Ab + An) is 96 to 100, indicating pure albitic nature of the plagioclase. A two-stage 'branching' differentiation is suggested for this petrological association.
Seismically Induced Deformational Structures (Seismites) from the Mid-Late Holocene Terraces, Lower Mahi Valley, Gujarat
Authors: Maurya D. M. , Rachna R. , Chamyal L. S. 
Published: November 2024

Abstract
Seismically induced deformational structures from the lower Mahi valley are reported. These include injected liquefied sand, contorted laminations, load structures, overturned small-scale folds and convolutions. syn-sedimentary microfaults and pseudonodules. The structures are similar to the seismically-induced deformation structures reported elsewhere and conform to the criteria for reiating them to seismic events. Radiocarbon dating of the two organic rich clay layers suggest the deformation is related to a Late Holocene seismic event that took place between 3320±90 and 2850±90 yrs. B.P.
Evolution and Resetting of the Fluids in Manikaran Quartzite, Himachal Pradesh: Application to Burial and Recrystallization
Authors: Sharma Rajesh , Misra D. K. 
Published: November 2024

Abstract
Primary aqueous fluid inclusions trapped in Manikaran Quartzite suggest a depth of burial about 4 to 7 km and entrapment temperature from 67 to 146°C. The later thrust-related recrystallization occurred in H2O-CO2 fluid regime under greenschist facies conditions. This event also resulted in thermal resetting of some aqueous inclusions trapped in original grains.
Ammonite Biozonation of the Middle-Late Jurassic Sediments with Special Reference to Keera and Jara Dome, Kachchh District, Gujarat
Authors: Prasad Surendra 
Published: November 2024

Abstract
A more refined ammonite biostratigraphy than hitherto proposed for the Middle to Late Jurassic sediments of Keera and Jara domes, Kachchh district, Gujarat is presented in this paper. Ammonite based six biozones (Triangularis, Formosus, Anceps, Athleta, Maya and Helenae) and thirteen subzones (Madagascariensis, Diadematus, Semilaevis, Anceps, Eucyclum, Singulare, Kleidos, Athleta, Lalandeanum, Semirugosus, Maya, Helenae and Kranaus) are distinguished in ascending oder for Pre-Callovian-Oxfordian rocks of Kachchh. The Triangularis Biozone is assigned to Pre-Callovian/Late Bathonian, the Formosus to Early Callovian, the Anceps to Middle Callovian, the Athleta to Late Callovian, the Maya to Early Oxfordian and the Helenae to Middle Oxfordian.
Occurrence of Beudantite from the Son Valley Gold Belt, Uttar Pradesh - A Preliminary X-Ray Study
Authors: Prasad R. , Rai S. , Kumar Alok , Dwiyedi G. N. , Tripathi A. K. , Yadav M. L. 
Published: November 2024

Abstract
A rare mineral Beudantite PbFe3 (AsO4)(SO4)(OH)6had been identified by X-ray diffraction technique in a weathered mineralised quartz vein, emplaced in phyllitic sequence. Its cell parameters are a=7.32Å. and c=17.13Å that are comparable to those of JCPDS-ASTM standard. Its association with corkite suggests that the area may have potential for silver and gold.
Preliminary Thermal Modelling of the Massif Anorthosite-Charnockitic Gneiss Interface from Gruber Mountains, Central Dronning Maud Land, East Antarctica
Authors: Ravikant V. 
Published: November 2024

Abstract
The Gruber massif-type anorthosite, with marginal noritic anorthosite, represents a lopolithic magmatic intrusion within the orogen exposed in the central Dronning Maud Land (cDML). The meta anorthosite, emplaced during the Dlb deformation event into the adjacent charnockitic gneiss (which had undergone an initial deformation event (Dla) equilibrated along with the charnockitic gneiss during granulite facies conditions (M1 = 787 ± 50°C, 7.4 ± 1kbar) followed by near isobaric cooling, M2 event The gneiss and anorthosite were then deformed and partly retrogressed during a M3 metamorphism (hydration during amphibolite facies conditions) accompanied by weak to moderate D2deformation.
Cooling of the anorthosite pluton (using a parameterized model with high initial crystallinity, a lower crustal contact temperature of ~800°C with an average radius of 17 km) from 1200 to 840°C would require c. 45 Ma, following which the cooling rate would fall to &lt;1 °C Ma-1. An initial transient elevated geotherm of interest which fits the extracted P,T conditions during the M1metamorphism was calculated, simulating the equilibration of the interface. Next, cooling and uplift of this interface with realistic combinations of thermal properties of the crust, heat generation, low uplift rates and boundary conditions was made. Calculation of the cooling and uplift of the equilibrated anorthosite and chamockitic gneiss interface produces an initial near isobaric cooling path for c. 30 Ma at or near the depth of equlibration.
Using available geophysical data from the cDML orogen, the causes for the thermal perturbation during the granulite facies metamorphism are discussed and it is proposed that the granulite facies metamorphism was caused by a combination of crustal thickening and magmatic underplating during the collision (i.e. crustal thickening followed by extension) of the Kalahari (equivalent) Craton and a proposed East Antarctica Craton during the Grenvillian/Kibaran event.