Iranian Journal of Earth Sciences
Volume:3 Issue: 1, Apr 2011

Cretaceous mafic dykes in the Moyar Shear Zone (MSZ) area, north Kerala, India, provide signatures to probe into the nature of their source and thereby the evolution of the Mesozoic lithospheric mantle beneath the South Indian Granulite Terrain (SIGT). Bulk of the dykes in northern parts of Kerala is broadly in spatial association with the shear system. Mafic dykes striking NE-SW, NWSE, NNW-SSE and ENE-WSW are widespread in the MSZ and surrounding areas. Width of these dykes varies from 30cm to 5m in general, while dykes wider than 10m also occur. These mafic dykes are olivine/quartz normative tholeiites showing strong correlation to N-Type MORB and within plate basalt affinity. Anisotropy of Magnetic Susceptibility (AMS) data imply normal magnetic fabrics nearly parallel to dyke trends, but with highly variable plunge of magnetic lineation. The compositions of the least altered and least metamorphosed dykes help to define the properties of their mantle source region, as well as the nature of the crust through which the magma traveled. The present contribution on the mafic dyke swarms in Moyar Shear Zone (MSZ) provides new interpretations on the temporal relations of magmatism and tectono-metamorphic evolution of the south Indian high grade terrain.

West Carpathian Mesozoic paleogeographic development indicates the effect of a left lateral shift of the Alpine- Carpathian microcontinent along the European shelf since the Early Jurassic. The evolution during Late Triassic/Early Jurassic was controlled by convergence along the border of the Meliata Ocean and by contemporaneous divergence along the Middle Atlantic/Penninic rift. During Mid-Cretaceous, the convergence between Africa and Paleoeurope started, which finally resulted in collision of Alpine-West Carpathian microcontinent with the Paleoeuropean margin and in the formation of the Alpine Orogen.

Principal component analysis is a valid method used for data compression and information extraction in a given set of experiments. It is a well-known classical data analysis technique. There are a number of algorithms for solving the problems, some scaling better than others. Wheat ranks as the staple food of most of the nations as well as an agent of poverty reduction, food security and world peace. Due to limited sowing time and conventional cropping pattern the wheat yield suffers. Efficient tillage methods maintain soil health and crops response. The present investigations were carried out to study the effects of different tillage systems on yield and yield contributing traits, using Randomized Complete Block Design. Two tillage systems i.e. conservation tillage and conventional tillage were used. Three principal components were sufficient to explain the variations. The traits plant height, number of leaves, number of tillers, peduncle length, spike length, number of spikelets per spike, number of grains per spike, grain weight per spike and grain yield were affected significantly under conservation tillage as well as conventional tillage systems. The graphic representation showed that yield contributing traits behaved best in conservation tillage practice. The present study revealed that conservation tillage method produced optimum yield for wheat production.

In (Part I), it was stated that red beds, conglomerates and salt were considered azoic and problematic rocks, but Paleopalynology and Inorganic Geochemistry proved to be useful for placing them in time and space. In the early last century, in Mexican NE region, only three Mesozoic red bed units were differentiated, dated as Late Triassic to Late Jurassic. It was important stratigraphically to place them properly as they were considered to be the basement of the marine petroliferous sequence in some Mexican Gulf of Mexico sub-basins. Palynostratigraphic studies since 1969, and X- ray analyses since 1989 allowed to place, in time and space, the Cahuasas, Huizachal, La Joya, and La Boca red bed units, outcropping at the Huizachal-Peregrina and Huayacocotla anticlinoria and, recently, the Rosario, Conglomerado-Prieto and Cuarcítica-Cualac units at the Tlaxiaco Anticlinorium. In this (Part II) it is described the method used for reconstructing the paleogeographic distribution of these red beds. Their correlation permitted to place the Liassic units as deposited in a half- graben connected to an Epicontinental Sinemurian Sea. This sea, during the Middle Jurassic, was invaded by the Tethysian waters through the Hispanic Corridor formed across the new Gulf of Mexico, which was originated by a hot spot with a triple junction.

The basement rocks encountered in exploratory boreholes drilled for exploration and evaluation of coal deposits in Thar Parkar district, Sindh Pakistan have formed the basis for present studies. The basement complex was penetrated through eighteen boreholes at drill depth range from 112 to 279 meters. These rocks were identified in field as Pink and Grey Granites.. The basement rocks are of Igneous as well as metamorphic origin. The Igneous rocks identified petrographically are Alkali-feldspar Granite, Granodiorite, Rhyolite, Rhyodacite and Aplite while that of metamorphic origin is Plagioclase Hornblende Gneiss. These rocks are termed as Thar Granitoids. The chemical data plotted in various binary and ternary diagrams suggests that the Thar Granitoids are (1) in general peraluminous in nature (2) restricted to psuedoternary minimum at moderate water pressure.

This article lists a number of geological data on the conditions of formation of some major gold deposits in the conglomerates of the Earth\'s crust. We analyze the metallogenic, tectonic, stratigraphic and other factors controlling the formation of gold-bearing conglomerates in certain fields, such as the Witwatersrand (S. Africa) and Darwaz (Tajikistan). The following tectonic factors play the leading role in controlling the formation of deposits of gold-bearing conglomerates in the Earth\'s crust:  Epochs of mountain building of different ages in folded belts;  Epochs of mountain building in activation of consolidated gold ore provinces in the domed uplifts of ancient shields, median areas and in areas with complete folding;  The role of lithogenesis of the molasse cycle, transgressions and angular unconformity in the formation of gold-bearing conglomerates in a large area;  Synchroneity with mountain building in gold ore provinces of different, intermountain molasse and marginal basins of various ages; and imposed volcanic and terrigenic conglomeratic molasse basins in activated gold ore provinces  Volcanic belts and deep faults. There are three industrial types of gold-bearing conglomerates: ancient Precambrian (indurated) sedimentary-metamorphosed placer, Phanerozoic cemented placer, and younger, weak, friable Pliocene-Pleistocene placers. We give some details about the methods for their exploration and financial costs for the development of selected industrial types of gold-bearing conglomerates. In this article, it is noted that during the Sassanian and the Mongolian Empire a certain amount of native gold was extracted from the Late Alpine molasse conglomerates which formed during the activation of gold ore area of the major Iranian middle massif. By analogy with the geological conditions of formation of deposits of gold-bearing conglomerates in the Earth\'s crust, the geological search criteria for deposits of gold-bearing conglomerates in some orogenic and widespread activated imposed conglomeratic molasse basins of Iran are given. A number of promising molasse conglomeratic basins are indicated: Mashhad intermountain deflection, as well as a number of superimposed molasse basins in the active superimposed volcano- plutonic belt of Iran, in particular Lut Block, middle massif, Tabriz, Ahar, and other superimposed molasse basins in the large Sabalan ring structure. In conclusion, we propose the development of selected areas and the establishment of new major resources of the gold - placer industry of Iran.

Deposits of the Warchha Sandstone in the Salt Range, Pakistan are characterised by a range of fluvial facies and architectural elements that together preserve a record of both the proximal and distal parts of a meandering river system that drained the northern margin of Gondwanaland. Several fining-upward cycles are recognised and completely preserved cycles can be divided in to three parts; a lower part composed of an erosive base with gravel- and coarse sand-grade trough cross-bedded facies, a middle part composed of planar cross-bedded, ripple cross-laminated and horizontally laminated sandstone facies, and an upper part composed predominantly of horizontally laminated and massive mudstone facies. Nine architectural elements are recognised within these cycles and these record the presence of channels, downstream and laterally accreting barforms, laminated sand sheets, crevasse splays, levees, over-bank floodplain units and shallow lakes. A broad range of sedimentary structures is recognised, including different forms of bedding, cross bedding, ripple marks and stratification, channels, flute casts, load casts, desiccation cracks, rain prints, conein- cone structures, a variety of concretions and bioturbation. The occurrence and abundance of these structures varies in a systematic manner throughout the vertical thickness of the succession. Cross bedding is the most prominent and consistent sedimentary structure, including various trough and planar varieties. The clasts are mainly of plutonic and low-grade metamorphic origin, with an additional minor sedimentary component. Textural properties of the sandstone are fine- to coarse-grained, poorly to moderately sorted, sub-angular to sub-rounded and with generally loose packing. Based on modal analyses, the sandstone is dominantly a sub-arkose to arkose. Detrital constituents of this formation are mainly composed of monocrystalline quartz, feldspars (more K-feldspar than plagioclase) and various types of lithic clasts. XRD and SEM studies indicate that kaolinite is the dominant clay mineral. Detailed palaeocurrent analysis reveals a broad unimodal palaeocurrent pattern within each cycle but significant changes in local migration direction between each vertically stacked cycle, supporting the notion of a high-sinuosity system with an overall dominant flow direction to the north-northwest. Petrographic analysis indicates the provenance of the Warchha Sandstone to have been the Aravalli Range to the southeast and the Malani Range to the south of the Salt Range, suggesting northward transport across a broad alluvial plain towards the margin of the Tethys Ocean in the north

Middle to Upper Triassic (Upper Ladinian to Lower Carnian) deep-sea sedimentary rocks crop out across a large area west of Nakhlak village, Central Iran and have been named Ashin Formation. The up to 304m thick, turbiditic, siliciclastic Ashin Formation consists of alternating turbiditic, thin- and medium-bedded calcareous sandstones, purple, fine-grained volcaniclastic sandstones, and mostly green and violet, very thin-bedded volcaniclastic shales that can be subdivided into three members. Ammonoids collected from members 1 and 3 of the Ashin Formation indicate a Late Ladinian to Early Carnian age for the formation. These alternations fine upwards and exhibit sedimentary structures such as graded bedding, parallel lamination (with parting lineation) convolute bedding, small-scale cross-bedding, load casts, groove casts, prod casts, flute casts, bounce casts, chevron casts, brush casts and chips and protraction traces indicating A to E parts of the Bouma cycle. Septarian nodules occur repeatedly. The lower surfaces of sandstones contain abundant trace fossils belong to the deep-sea Nereites ichnofacies. Numerous signs of strong current activity such as groove casts, flute casts and prod marks associated with trace fossils such as Paleodictyon, Protopaleodictyon, Megagrapton and Lorenzinia indicate that the Ashin Formation represents a deep marine environment. The field and petrographic studies show that the Ashin Formation was deposited in distal parts of submarine fans, on the abyssal plain.

The components and quantities of atmospheric dusts fallout has been reported to be the pollution indicator of large urban areas. The multiplicity and complexity of sources of atmospheric dusts in urban regions (e.g. industrial complexes composed of a variety of industrial processes, automobiles, construction activities etc.) has put forward the need of source apportionment of these sources indicating their contribution to specific environmental receptor. The study presented here is focused on investigation of source contribution estimates of dusts fallout in an urban-industrial area, Raipur, India. Six sampling sites have been identified on the basis of land use for development plan of anthropogenic activities and factors related to the transportation and dispersion pattern of atmospheric dusts. 12 samples of dusts fallout has been collected from each site (one in each month) and subjected to chemical analysis of selected chemical constituents known as markers of selected major dust emitting sources(Steel making average, Road traffic-borne dusts, construction activities, municipal waste burning, and soils). Chemical profiles alongwith SPECIATE of USEPA has been used for the preparation of source profiles. Source apportionment has been done using Chemical Mass Balance (CMB 8). Good fit parameters and relative source contribution has been analyzed and documented. Variations in source contribution estimates of selected indicator species has been occurred and justify the significant contribution of local area and line sources of dusts emission in various parts of the study region. Soil has shown different contribution for different radical.