Changing land use/land cover patterns and growing human population in Wular catchment of Kashmir Valley,India

GeoJournal - The profound increase in human activities and the degrading scenario in fragile ecosystems of the western Himalayas like that of Wular Lake have highlighted the need to analyze the...     

GIS-based spatial landslide distribution analysis of district Neelum,AJ&K,Pakistan

Natural Hazards - The Landslide happens in mountainous regions due to the catastrophe of slope through intensive rain and seismicity. The Himalayas is one of the susceptible parts of the world in...     

Vorticity Analysis and Deformation History of the Mizil Gneiss Dome,Eastern Arabian Shield,Saudi Arabia

The Mizil gneiss dome is an elliptical structure consisting of an amphibolite-facies volcanosedimentary mantle and a gneissic granite core. This dome is located at the northern tip of the Ar Rayn terrane only a few kilometers from the eastern edge of the Arabian shield. Previous investigations have shown the intrusive core to be an adakitic diapir with a U–Pb zircon age of 689 ± 10 Ma; this age is 50–80 Ma years older than other granites in this terrane. Vorticity analysis was carried out on samples from the intrusive core and volcanosedimentary cover; the Passchier and Rigid Grain Net (RGN) methods were used to obtain the kinematic vorticity number (W_k) and the mean kinematic vorticity number (W_m). The W_k and W_m values show a marked increase towards the south; such a pattern indicates a N-S movement of the core pluton thus creating an inclined diapir tilted to the south. Analogue experiments simulating the flow of magma diapirs rising form a subducted slab through the mantle wedge have shown that supra-subduction zone oblique diapirs are produced close to the trench and are elongated normal to the convergence direction as is the case in the Mizil pluton. This effect was found to increase with increasing slab dip due to enhanced drag along the upper surface of the subducted lithospheric plate. Spontaneous subduction which is often associated with rollback resulting in back-arc extension and steep dipping slabs is thought to have occurred in the Mozambique Ocean by 700 Ma. The Mizil pluton is coeval with the back-arc Urd ophiolite from the adjacent Dawadimi terrane, and could therefore have been produced by incipient subduction of a relatively cold slab as observed in many Pacific margin adakites. The tectonic evolution of the eastern shield, as deduced from the Mizil dome and other data from Ar Rayn and neighboring terranes, begins with the subduction of >100 My-old lithosphere beneath the Afif terrane resulting in back-arc spreading and the splitting of the Ar Rayn arc from the Afif microplate, with the concomitant production of a small volume of adakite melt. Other arc terrane(s) docked east of Ar Rayn with the westward-directed subduction still going but a lower angles and greater depth due to trench jump; this phase produced the more prevalent non-adakitic group-1 granites. A major collisional orogeny affected the entire eastern shield between 620–600 Ma and sutured the eastern shield terranes with northern Gondwana.     

Improvement in Engineering Properties of Expansive Soils using Ground Granulated Blast Furnace Slag

Improvement in engineering properties of expansive soils by mixing ground granulated blast furnace slag (GGBFS) is the main focus of this research. For this purpose two expansive soil samples were collected from DG Khan and Sialkot areas (Pakistan). Classification tests revealed that DG Khan sample belonged to fat clay (CH) while Sialkot soil was lean clay (CL) as classified by Unified Soil Classification System. GGBFS has been added in varying proportions between 0 and 55% in these soil samples to study its role in stabilizing these expansive soils. Based on the laboratory test performed on composite soil samples, it was observed that maximum dry unit weight increased up to 10 % by adding 50% GGBFS in both samples. California bearing ratio (CBR) value showed an increase from 3.2 % to 11.5% for DG Khan soil while CBR values varied from 2.4% to 10.7% for Sialkot soil by mixing 50% GGBFS. Addition of 30 % GGBFS to DG Khan soil reduced swell potential from 8 % to 2 % while in Sialkot soil, 20 % addition of GGBFS reduced swell potential from 5 % to 2 %. Unconfined compressive strength of remoulded sample cured for 28 days increased by about 35% with the addition of 30%GGBFS. The results indicated that mixing of GGBFS in the expansive soil samples have a marked increase in their engineering properties. Also, it is an affective and environmental friendly means to dispose waste of steel industry.     

Seismic hazard and probability assessment of Kashmir valley,northwest Himalaya,India

Seismic hazard analysis of the northwest Himalayan belt was carried out by using extreme value theory (EVT). The rate of seismicity (a value) and recurrence intervals with the given earthquake magnitude (b value) was calculated from the observed data using Gutenberg–Richter Law. The statistical evaluation of 12,125 events from 1902 to 2017 shows the increasing trend in their inter-arrival times. The frequency–magnitude relation exhibits a linear downslope trend with negative slope of 0.8277 and positive intercept of 4.6977. The empirical results showed that the annual risk probability of high magnitude earthquake M?≥?7.7 in 50 years is 88% with recurrence period of 47 years, probability of M?≤?7.5 in 50 years is 97% with recurrence period of 27 years, and probability of M?≤?6.5 in 50 years is 100% with recurrence period of 4 years. Kashmir valley, located in the NW Himalaya, encompasses a peculiar tectonic and structural setup. The patterns of the present and historical seismicity records of the valley suggest a long-term strain accumulation along NNW and SSE extensions with the decline in the seismic gap, posing a potential threat of earthquakes in the future. The Kashmir valley is characterized by the typical lithological, tectono-geomorphic, geotechnical, hydrogeological and socioeconomic settings that augment the earthquake vulnerability associated with the seismicity of the region. The cumulative impact of the various influencing parameters therefore exacerbates the seismic hazard risk of the valley to future earthquake events.     

Geochemistry of garnet in pegmatites from the Boroujerd Intrusive Complex,Sanandaj-Sirjan Zone,western Iran: implications for the origin of pegmatite melts

Mineralogy and Petrology - Pegmatite-hosted garnets from four localities in the Boroujerd region, Lorestan (Western Iran), have been analysed for major and selected trace element compositions. The...     

Bartonian orthophragminids with new endemic species from the Pirkoh and Drazinda formations in the Sulaiman Range,Indus Basin,Pakistan

The Pirkoh and Drazinda formations in the Sulaiman Range, central Pakistan, yielded assemblages of (early) Bartonian orthophragminids, characterized predominantly by discocyclinids with a significant number of species probably endemic to Indian Subcontinent. The rarity of Asterocyclina and the absence of Orbitoclypeus and Nemkovella are noteworthy. Ten species of Discocyclina Gümbel and two species of Asterocyclina Gümbel, referable to the Shallow Benthics Zone (SBZ) 17 are described for the first time from Pakistan. The discocyclinids, i.e. Discocyclina praeomphalus, D. sulaimanensis, D. kutchensis, along with the new taxa established here, D. zindapirensis sp. nov., D. rakhinalaensis sp. nov., and D. pseudodispansa sp. nov., seem to be confined to the Indo-Pakistani region (Eastern Tethys). The Discocyclina dispansa, D. discus, D. nandori, and D. augustae lineages known from Western Tethys are also common in the Indian Subcontinent, as are asterocyclinids, such as Asterocyclina sireli and A. stellata. The upper part of the Drazinda Formation (‘Pellatispira beds’), referable to latest Bartonian and/or the early Priabonian, is poor in orthophragminids and is characterized by the occurrence of reticulate Nummulites, Heterostegina, Pellatispira and Silvestriella. The records of ‘Lepidocyclina of Caribbean affinity’ with large embryons from the Eocene of the Indian Subcontinent correspond to misidentified Discocyclina discus.     

Petrogenesis of Rabor-Lalehzar magmatic rocks (SE Iran): Constraints from whole rock chemistry and Sr-Nd isotopes

The Urumieh-Dokhtar magmatic arc (UDMA) of Central Iran has been formed during Neotethyan Ocean subduction underneath Eurasia. The Rabor-Lalehzar magmatic complex (RLMC), covers an area ～1000?km² in the Kerman magmatic belt (KMB), SE of UDMA. RLMC magmatic rocks include both granitoids and volcanic rocks with calc-alkaline and adakitic signatures but with different ages.Miocene adakitic rocks are characterd by relatively enrichmented in incompatible elements, high (Sr/Y)_(N) (>40), and (La/Yb)_(N) (>10) ratios with slightly negative Eu anomalies (Eu_N/Eu*≈ 0.9), depletion in HFSEs, and relatively non-radiogenic Sr isotope signatures (⁸⁷Sr/⁸⁶Sr?=?0.7048–0.7049). In contrast, the Oligocene granitoids exhibit low Sr/Y (<20) and La/Yb (<9) ratios, negative Eu anomalies (Eu_N/Eu*?≈?0.5), and enrichment in HFSEs and radiogenic Sr isotope signatures (⁸⁷Sr/⁸⁶Sr?=?0.7050–0.7052), showing affinity to the island arc rocks. Eocene volcanic rocks which crusscut the younger granitoid rocks comprise andesites and dacites. Geochemically, lavas show calc-alkaline character without any Eu anomaly (Eu_N/Eu*?≈?1.0). Based on the geochemical and isotopic data we propose that melt source for both calc-alkaline and adakitic rocks from the RLMC can be related to the melting of a sub-continental lithospheric mantle (SCLM). Basaltic melts derived from a metasomatized mantle wedge might be emplaced at the mantle-crust boundary and formed the juvenile mafic lower crust. However, some melts fractionated in the shallow magma chambers and continued to rise forming the volcanic intermediate-mafic rocks at the surface. On the other hand, the assimilation and fractional crystallization in the shallow magma chambers of may have been responsible for the development of Oligocene granitoids with calc-alkaline affinity. In the mid-Late Miocene, following the collision between Afro-Arabia and Iranian block the juvenile mafic crust of UDMA underwent thickening and metamorphosed into garnet-amphibolites. Subsequent upwelling of a hot asthenosphere during Miocene was responsible for partial melting of thickened juvenile crust of the SE UDMA (RLM complex). The adakitic melts ascended to the shallow crust to form the adakitic rocks in the KMB.