Muhammad Rustam Khan

Geotechnical study of marble, schist, and granite as dimension stone: a case study from parts of Lesser Himalaya, Neelum Valley Area, Azad Kashmir, Pakistan

Extensive production of concrete and bricks has reduced the use of stone masonry in construction. The overwhelming use of artificial material, especially concrete, has led to many environmental issues. Use of dimension stone is almost non-existent in general construction. Nonetheless, it is still widely adopted in foundations, facings, dams, coastal defenses, and retaining and water containment structures. For the possible rational replacement of artificial materials, marble, schist, and granite were selected for evaluation as dimension stones. Important properties influencing the behaviour of construction material, such as compressive strength, tensile strength, durability, water absorption, and petrography, were investigated on selected rocks. The results were correlated with standard specifications of ASTM, ISO 14689-1 (Geotechnical investigation and testing. Identification and classification of rock. Part 1: Identification and description 1–16, 2003) and Gamble durability index (1971). Regional faults, Main Boundary Thrust, and Panjal Thrust, present in the area influence the characteristics of rocks adversely. Granite has a lower compressive strength than the ASTM specification so it should be avoided for load-bearing masonry units and external pavements. Granites and marbles have a higher degree of water absorption. All three rock units have a very high degree of polish, so their use as decorative stone, especially as internal flooring and at internal walls, is highly recommended.

Tectonic study of the Sub-Himalayas based on geophysical data in Azad Jammu and Kashmir and northern Pakistan

The tectonic study based on geophysical data has been carried out in Sub-Himalayas in Azad Jammu and Kashmir and northern Pakistan. A series of thin skinned and thick skinned faults have been delineated in the investigated area on the basis of present study. In the study area compressional stresses caused by the collisional of Indian and Eurasian plates developed the northwestsoutheast trending faults which are Shaheed Gala thrust, Bagh basement fault, Kashmir boundary thrust and Kawai fault or Indus Kohistan seismic zone. The crustal thickness increases towards north due to the stacking of the thrust sheets along these faults. The Murree Formation thrusts over the Siwaliks molasse along the Shaheed Gala thrust. This fault dips at an angle of 43º northeast and joins the thick skinned Bagh basement fault in subsurface which are penetrated up to Moho depth. In the northeast of Bagh basement fault the northwest-southeast trending Kashmir boundary thrust has been delineated in the sedimentary-metasedimentary wedge which joins the Indus Kohistan seismic zone in the subsurface. The present study suggested that the Kawai fault which is running within Murree Formation cuts 16 km thick sedimentary-metasedimentary wedge and also joins the Indus Kohistan seismic zone in the subsurface.

Petrology and geochemistry of Jura granite and granite gneiss in the Neelum Valley, Lesser Himalayas (Kashmir, Pakistan)

Late Proterozoic rocks of Tanol Formation in the Lesser Himalayas of Neelum Valley area are largely green schist to amphibolite facies rocks intruded by early Cambrian Jura granite gneiss and Jura granite representing Pan-African orogeny event in the area. These rocks are further intruded by pegmatites of acidic composition, aplites, and dolerite dykes. Based on field observations, texture, and petrographic character, three different categories of granite gneiss (i.e., highly porphyritic, coarse-grained two micas granite gneiss, medium-grained two micas granite gneiss, and leucocratic tourmaline-bearing muscovite granite gneiss), and granites (i.e., highly porphyritic coarse-grained two micas granite, medium-grained two micas granite, and leucocratic tourmaline-bearing coarse-grained muscovite granite) were classified. Thin section studies show that granite gneiss and granite are formed due to fractional crystallization, as revealed by zoning in plagioclase. The Al saturation index indicates that granite gneiss and granite are strongly peraluminous and S-type. Geochemical analysis shows that all granite gneisses are magnesian except one which is ferroan whereas all granites are ferroan except one which is magnesian. The CaO/Na2O ratio (>0.3) indicates that granitic melt of Jura granite gneiss and granite is pelite-psammite derived peraluminous granitic melt formed due to partial melting of Tanol Formation. The rare earth element (REE) patterns of the Jura granite and Jura granite gneiss indicate that granitic magma of Jura granite and Jura granite gneiss is formed due to partial melting of rocks that are similar in composition to that of upper continental crust.

Determination of aquifer properties and vulnerability mapping by using geoelectrical investigation of parts of Sub-Himalayas, Bhimber, Azad Jammu and Kashmir, Pakistan

A resistivity survey has been carried out for the determination of aquifer properties and vulnerability mapping of part of the Sub-Himalayas in the Bhimber District of Azad Jammu and Kashmir, Pakistan. In the study area 19 vertical electrical sounding points were established using a Schlumberger configuration. The acquired data were processed using IPI2WIN software and interpreted in terms of true resistivity and thickness of layers. The underlying lithology is loose soil, sandy clay, clay and sand. Productive groundwater zones have been identified in the central, southeastern and northwestern parts of the study area. The aquifer thickness varies considerably (6.4–224 m). On the aquifer vulnerability map, values >0.2 mhos indicate zones of moderate to good protective capacity, whereas values <0.19 mhos indicate vulnerable zones with risk of contamination. However, the aquifer is permeable and the central part has a low protective capacity and is vulnerable to infiltration of polluted fluid. The 2D resistivity inverse model and conductivity mapping delineate the contaminated plumes in the areas of poor to weak protective capacity. Chemical analysis shows that the central part of the study area is highly contaminated with magnesium, nitrate and sulphate.

Large scale mass movements triggered by the Kashmir earthquake 2005, Pakistan

The SPOT image analysis in Muzaffarabad Azad Kashmir, northwest Himalayas, Pakistan reveals that the Kashmir earthquake 2005 triggered a number of coseismic mass movements along the hanging wall block of the Muzaffarabad Fault. The Neelidandi and Langarpura rock falls have been identified as two major reactivated mass movements with an estimated volume of 3.1 × 106 m3 and 5.76 × 106 m3, respectively. The Neelidandi and Langarpura mass movements were initiated during earthquake in the direction of northwest-southeast extension and northeast-southwest directed thrusting, respectively. The Neelidandi rock fall occurred in sheared cherty dolomites and limestones of the Cambrian Muzaffarabad Formation, whereas the Langarpura rock fall occurred in alternating clays, shales, claystones, siltstones and sandstones of the Miocene Murree Formation. These rock units along the fault are highly fractured and jointed. The geotechnical maps and geological longitudinal profiles show the relationship between the geometrical characteristics and mechanism of these mass movements. Their characteristics were analyzed according to the role of topographic, seismic, geological and tectonic factors. The steep topography, sheared rocks, lithology, coseismic uplift and strong ground shaking of the hanging wall block along Muzaffarabad Fault facilitated the gravity collapse of these mass movements.

Application of gravity and magnetic methods for the crustal study and delineating associated ores in the western limb of Hazara Kashmir Syntaxis, Northwest Himalayas, Pakistan

The present geophysical study deals with the ores and crustal demonstration of southeastern Hazara and its adjoining areas of Azad Jammu and Kashmir, Pakistan, on the basis of terrestrial gravity and magnetic data. Tectonically, the study area lies in the Lesser Himalayas as well as to an extent in the sub-Himalaya, more specifically in the western limb of Hazara Kashmir Syntaxis. In this study, 567 gravity and 508 magnetic stations have been measured with CG-5 gravimeter and proton precession magnetometer, respectively. The collected data have been processed by applying standard corrections and then different types of maps were prepared. The ores in the area have been delineated by the qualitative interpretation of residual Bouguer anomaly and reduction to pole total magnetic intensity maps, whereas regional structures are demarcated by the Bouguer anomaly and regional Bouguer anomaly maps. The positive contour closures on the residual Bouguer anomaly map indicate the iron ore and phosphate, whereas negative contour closures are the effects of low-density material which consists of gypsum and soapstone. The pole-reduced total intensity map also shows the negative and positive contour closures almost in the same localities and confirms the residual Bouguer anomaly map. The geological model computed on the basis of Bouguer anomaly demarcated a series of faults between different rock units in the study area. The Kashmir Boundary Thrust cuts the western limb of Hazara Kashmir Syntaxis near the apex in the north of Muzaffarabad and marks the boundary between Murree Formation and carbonates of Abbottabad Formation. The gravity model also suggests that the thickness of the crust increases towards the northeast.