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The Wadhrai granite stock is a part of the Nagar Parkar Igneous Complex, an extension of the Neoproterozoic Malani Igneous Suite of western Rajasthan. It is occupied by a petrographically uniform granite comprising perthite, plagioclase, quartz, with small quantities of biotite, opaque oxides, titanite, and secondary minerals. The rocks are sparingly porphyritic and contain dykes of microgranite, aplite, and rare pegmatite. In the south-central part, parallel sheets and swarms of mafic dykes, and in the western part very fine-grained felsic sheets intrude the body. The granite is metaluminous to peraluminous and characterized by high silica (73–76 wt%), and alkalis (7–9 wt%), and low CaO (0.15–1.4 wt%), MgO (0.15–0.38 wt%), Th (7–12 ppm), and U (1–2 ppm). On geochemical discriminant diagrams, it classifies mostly as A-type (with rather high Y/Nb (8.6 to 2.4, average 5.2) and low Nb/Ga and Ce (typical of A2-type), but sparingly as I-type. Chondrite-normalized patterns show enrichment in LREE over HREE, and small negative Eu anomalies, whereas mantle-normalized spidergrams display higher LILE over HFSE, distinct troughs for Nb, Sr, P, Ti, and spikes for La, Ce, Nd, Sm and Tb. The granite magma was possibly derived from a tonalite-granodiorite-dominated crustal source. Based on the above-mentioned geochemical evidence, it is interpreted that the source rocks of the magma of the Wadhrai granite likely developed initially in a continental margin subduction setting and underwent partial melting in a continental extensional environment.

It has been 15 years since the catastrophic 2005 Kashmir Mw 7.6 earthquake induced thousands of landslides in northern Pakistan and Kashmir. There have been many studies on various aspects of the landslides triggered by the earthquake, such as the mechanisms of individual large landslides, regional seismic landslide inventory mapping, spatial distribution pattern, susceptibility and hazard assessment, and landslide evolution, which provide beneficial scientific results. However, there is currently no summary and generalization of these studies for ready use of the researchers to fully understand the information of the landslide caused by the earthquake. This study comprehensively reviews and summarizes the important results obtained from published data on the landslides. The seismogenic and regional active faults, fragile lithological condition, heavy rainfall, anthropogenic activities, and steep terrain were considered as main controlling factors for the landslide occurrence. Studies on landslide evolution reveal that vegetation on most of the landslides was partially recovered after the earthquake, while slope failures along roads and drainages increased. In the affected area, landslides are still a great threat to communication networks and communities. Despite many past studies, there is still a need or in-depth research using more precise methods to understand the mechanism, hazard, and risk assessment, numerical simulation, landslide risk management and mitigation, and continuous or temporal monitoring of landslides in the affected area. Combined with high-quality data on landslides triggered by other earthquake events in recent years, the study points out the prospects of Kashmir earthquake-induced landslides and summarizes the future challenges of earthquake-triggered landslides research, including accuracy of inventories, the precision of landslide, susceptibility methods, prevention and control of landslide, and landslide hazards and risk assessment. This review can provide a reasonable scientific research and disaster prevention and mitigation strategy and scheme for landslides triggered by a large earthquake in the future.

We present a detailed LA-ICP-MS U–Pb age data of zircons from the Nagar Parkar Igneous Complex in order to evaluate the duration of the Late Proterozoic magmatism in the Indian Shield. Igneous zircons from gray and pink granites in the complex have been investigated texturally, morphologically, and finally measured for 207Pb/206Pb, 207Pb/235U, 206Pb/238Pb, and 208Pb/232Th isotope ratios. Most of the zircons are euhederal, oscillatory zoned, and contain common inclusions of needle-like apatite and less common monazite, xenotime, and K-feldspar. Selected grains in six samples from gray and pink granites were analyzed for U–Pb dating and the results plotting on or near the concordia were used for interpretation. Zircons from four samples of gray granites yielded U–Pb mean ages of 751 ± 9 Ma (MSWD = 0.29) with concordia intercepting at 750 ± 9 Ma (MSWD = 0.29) for sample NGP62a, 726 ± 13 Ma (MSWD = 1.6) with concordia intercepting at 731 ± 15 Ma (MSWD = 1.7) for sample NGP62b, 662 ± 13 Ma (MSWD = 2.7) with concordia intercepting at 711 ± 27 Ma (MSWD = 0.98) for sample NP12, and 740 ± 9 Ma (MSWD = 1.3) with concordia intercepting at 736 ± 12 Ma (MSWD = 1.3) for sample NP62. One sample (NP01) from grayish white granite gave U–Pb mean age of 699 ± 26 Ma (MSWD = 10.4) with concordia intercepting at 62 and 950 Ma (MSWD = 2.8). Similarly, zircons from one sample from pink granite (sample NP10) yielded U–Pb mean age of 713 ± 32 Ma (MSWD = 1.5) with concordia intercepts at 726 ± 41 Ma (MSWD = 1.9). The combined U–Pb zircon age data from the analyzed samples show a continuous crustal growth, from 775 Ma until 640 Ma, indicating a magmatic span of >100 million years. The magmatism in the Nagar Parkar Igneous complex, a part of the Indian Shield, could be associated with an earlier Andean-type tectonic setting in the Rodinia supercontinent followed by rift-related extensional tectonic setting during the Neoproterozoic Era. Our comprehensive age data thus define a precise time span of crustal growth in the Indian Shield between 640 and ~775 Ma and refine the previously reported ages spanning between 1.1 Ga and 0.75 Ga.

The Neo-Tethys Ocean separated the India and the Karakoram block of southern Asia during the late Mesozoic. Most native records have been significantly obscured by multiply later deformation and metamorphism during the early Tertiary India-Asia collision, the consecutively opening and closure evolutionary of the Neo-Tethys is least understood. This paper presents new petrologic, bulk rock major and trace elements, and zircon U-Pb age and Hf isotopic investigation on the recently identified Karimabad meta˗granodiorites in the southern Karakoram block, N Pakistan. The results indicated these meta˗granodiorites experienced one stage of crystallization (150 ± 0.8 Ma, n = 28, MSWD = 1.5) and at least one stage of metamorphism (59 to 63 Ma) events. The Late Jurassic meta˗granodiorites display some adakite-like geochemical features, such as high SiO2 (68.0–69.2 wt%), Al2O3(16.4–187 wt%), Sr (386–526 ppm), low Y (6.5–13.8 ppm) and Yb (0.49–0.98 ppm) contents, and thus high Sr/Y (32.8–72.0) ratios. In addition, they have low MgO (0.67–1.12 wt%), Mg# (36.0–47.8) and K2O/Na2O (0.32–0.36) with positive zircons ԐHf(t) values from +7.1 to +14.0. Few zircon grains from the same meta-granodiorite yielded values around 59–63 Ma, respectively, that may be associated with the metamorphic events associated with the crustal thickening soon before or during the later continental collision. Combining with previous researches, we suggest that these igneous rocks are related to Neo-Tethys oceanic lithosphere break-off beneath the Karakoram block, and the northward subduction initiated at the Late Jurassic (~150 Ma).

The Late Cretaceous Chagai arc outcrops in western Pakistan, southern Afghanistan and eastern Iran. It is in the Tethyan convergence zone, formed by northward subduction of the Arabian oceanic plate beneath the Afghan block. The oldest unit of the Chagai arc is the Late Cretaceous Sinjrani Volcanic Group. This is composed of porphyritic lava flows and volcaniclastic rocks, and subordinate shale, sandstone, limestone and chert. The flows are fractionated low-K tholeiitic basalts, basalticandesites, and andesites. Relative enrichment in their LILE and depletion in HFSE, and negative Nb and Ta and positive K, Ba and Sr anomalies point to a subduction-related origin. Compared to MORB, the least fractionated Chagai basalts have low Na2O, Fe2O3T, CaO, Ti, Zr, Y and 87Sr/86Sr. Rather than an Andean setting, these results suggest derivation from a highly depleted mantle in an intraoceanic arc formed by Late Cretaceous convergence in the Ceno-Tethys. The segmented subduction zone formed between Gondwana and a collage of small continental blocks (Iran, Afghan, Karakoram, Lhasa and Burma) was accompanied by a chain of oceanic island arcs and suprasubduction ophiolites including Semail, Zagros, Chagai-Raskoh, Kandahar, Muslim Bagh, Waziristan and Kohistan-Ladakh, Nidar, Nagaland and Manipur. These complexes accreted to the southern margin of Eurasia in the Late Cretaceous.

Kharsar hill is one of many granitic plutons comprising the Nagar Parkar igneous complex. The eastern part of the hill is occupied by grey-pink granite (earlier) and the western part by pink granite (later). They are composed of perthite, quartz, and plagioclase, with minor opaque oxide, biotite, titanite, local amphibole, and secondary chlorite, epidote, leucoxene/titanite. The pink granite is characterized by the presence of mafic clots. Both the granitoids are intruded by microgranite/aplite, and porphyritic mafic and rhyolite dykes, locally in swarms. These are abundant in a NE trending 200 m wide zone cutting the entire granite hill. The dykes may extend over 1 km in length and >10 m in thickness, but most are < 100 m in length. The felsic dykes are of several generations; some are associated with the two varieties of granite, others are contemporaneous with the rhyolite and mafic dykes. The mafic dykes can be grouped into two types one of which contains hornblende and the other augite as the principal mafic mineral. Major element analyses suggest that the granitic rocks are metaluminous. The Kharsar granites, like the others in Nagar Parkar, may be an extension of the Malani igneous suite of Rajasthan. The occurrence of bimodal mafic-felsic dykes and petrographic variation in the mafic dykes are briefly discussed.

We investigated zircons from the Nagar Parkar Igneous Complex (NPIC) Gray and Pink granites for hafnium isotope and trace elements geochemistry to elucidate their petrogenetic source and tectonic setting. The studied zircons are characterized by oscillatory zoning, contain micro-inclusions of apatite, monazite, xenotime, and plagioclase. Rare-earth elements of the Neoproterozoic (ca. 750 Ma) zircons are characterized by a positive slope from La to Lu, exhibit distinct positive Ce- and negative Eu-anomalies that suggest their crystallization in magma that was fractionating plagioclase. The relatively smaller but variable Ce/Ce*N ratios (2–62), smaller Eu/Eu*N (0.01 to 0.45), and comparatively higher Th/U ratios (>0.30, reaching up to 3.20) affirm their derivation mainly from the continental crustal type magmas. The eHf(t) values of zircons in Gray and Pink granites range from +5.7 to +14.4 and +1.9 to +10.7, respectively, indicate their derivation from a juvenile crust and the absence of negative eHf(t) values point towards non-involvement of the older or reworked material during the crustal growth. The TDM model ages, calculated from the Hf isotope values of zircons, spread between 1119 and 736 Ma for Gray and 1013 and 900 Ma in Pink granites, further opine their derivation from a comparatively young and juvenile crust. Crystallization temperatures, estimated from the titanium content in zircon and zircon-saturation in whole-rock, range from 631 to 905 °C and 784 to 918 °C, respectively, show consistent results for the crystallization conditions of most granitic melts. Whole-rock major and trace element data, combined with zircon Hf isotope and trace elements geochemistry suggest within-plate A-type granitic magma that likely generated in a rift-related tectonic setting that persisted along the western margin of Rodinia during the Neoproterozoic era.

Basaltic volcanic conglomerates near the Wulgai village in Balochistan occur in the undivided sedimentary rock unit of the Bagh complex which is the melange zone beneath the Muslim Bagh ophiolite. The presence of Middle Triassic grey radiolarian chert within the upper and lower horizon of the conglomerates suggests that the lavas, from which these conglomerates were principally derived, were eroded and re-deposited in the Middle Triassic. The Wulgai conglomerate contains several textural and mineralogical varieties of volcanic rocks, such as porphyritic, glomerophyric, intersertal and vitrophyric basalts. The main minerals identified in these samples are augite, olivine, plagioclase (An35-78) leucite and nosean, with apatite ilmenite, magnetite and hematite occurring as accessory minerals. These rocks are mildly to strongly-alkaline with low Mg# and low Cr, Ni and Co contents suggesting that their parent magma had undergone considerable fractionation prior to eruption. Trace element-enriched mantle-normalized patterns with marked positive Nb anomalies are consistent with 10%-15% melting of an enriched mantle source in a within-plate tectonic setting. It is proposed that this Middle Triassic intra-plate volcanism may represent mantle plume-derived melts related to the Late Triassic rifting of micro-continental blocks (including Afghan, Iran, Karakorum and Lhasa) from the northern margin of Gondwana.

The Chilas Complex is a major lower crustal component of the Cretaceous Kohistan island arc and one of the largest exposed slices of arc magma chamber in the world. Covering more than 8000 km2, it reaches a current tectonic width of around 40 km. It was emplaced at 85 Ma during rifting of the arc soon after the collision of the arc with the Karakoram plate. Over 85% of the Complex comprises homogeneous, olivine-free gabbronorite and subordinate orthopyroxene–quartz diorite association (MGNA), which contains bodies of up to 30 km2 of ultramafic–mafic–anorthositic association (UMAA) rocks. Primary cumulate textures, igneous layering, and sedimentary structures are well preserved in layered parts of the UMAA in spite of pervasive granulite facies metamorphism. Mineral analyses show that the UMAA is characterized by more magnesian and more aluminous pyroxene and more calcic plagioclase than those in the MGNA. High modal abundances of orthopyroxene, magnetite and ilmenite (in MGNA), general Mg–Fe–Al spatial variations, and an MFA plot of whole-rock analyses suggest a calc-alkaline origin for the Complex. Projection of the pyroxene compositions on the Wo–En–Fs face is akin to those of pyroxenes from island arcs gabbros. The presence of highly calcic plagioclase and hornblende in UMAA is indicative of hydrous parental arc magma. The complex may be a product of two-stage partial melting of a rising mantle diaper. The MGNA rocks represent the earlier phase melting, whereas the UMAA magma resulted from the melting of the same source depleted by the extraction of the earlier melt phase. Some of the massive peridotites in the UMAA may either be cumulates or represent metasomatized and remobilized upper mantle. The Chilas Complex shows similarities with many other (supra)subduction-related mafic–ultramafic complexes worldwide.

The Hindu Kush–Kohistan–Karakoram region is critical to understanding the long-term accretion history of the south Asian margin pre-and post-India–Asia collision and the impact of these collisions on the development of high topography. However, knowledge about this region remains incomplete owing to sparse studies. Here, we present a study comprising detrital zircon U–Pb geochronology, detrital muscovite40Ar/39 Ar thermochronology and numerical modelling on40Ar/39 Ar dates. The study identifies zircon U–Pb age peaks at 200, 110–130, 60–80 and 28–40 Ma, supporting the polyphase collisions and crustal growth in the south Asian margin. The modelling study reveals fast cooling–erosion at 115–129, 69–71, 27–35 and

The Nagar Parkar Igneous Complex consists of Neoproterozoic igneous and metamorphic rocks dissected by mafic, felsic, and rhyolitic dykes. The latter can be classified broadly into porphyritic felsic dykes intruding gray and pink granites at Nagar Parkar and the surrounding areas, and the orthophyric felsic dykes intruding amphibolites, deformed pink granites, and the alkaline mafic dykes in the Dhedvero area, north of Nagar Parkar. The porphyritic felsic dykes are composed of perthites, quartz, and albitic plagioclase whereas the orthopheric felsic dykes contain K-feldspar (dominant), plagioclase, and minor quartz. Geochemically, the porphyritic and orthophyric felsic dykes are subalkaline and alkaline demonstrating post-orogenic A2- and OIB-A1-type characteristic on Nb–Y–Ce and Nb–Y–3Ga ternary plots, respectively. One orthophyric felsic dyke contains normative acmite and sodium metasilicate. This study suggests two distinct tectonic regimes for the origin of the felsic dykes of the area. The porphyritic felsic dykes show similarities with the ~800–700 Ma granites of the area, the rhyolite dykes of the Mount Abu, western Rajasthan in India, and the granites of the Seychelles microcontinent. The orthophyric felsic dykes show chemical resemblance with the Tavidar volcanic suite of western Rajasthan and the Silhouette and North islands of the Seychelles microcontinent. This study confirms spatial and temporal links among the Rodinian fragments exposed in the Nagar Parkar area of Pakistan, western Rajasthan of India, and the Seychelles microcontinent.

A pictorial review and brief description of metabasites (mainly eclogites) exposed in the western part of Himalaya, north Pakistan are presented. The metabasites occur in the Kaghan and Neelum valleys in the form of thick sheets, dikes, lenses, and zoned bodies. On the basis of petrography and mineral paragenesis, they can be distinguished into greenschist, amphibolites, garnet-amphibolites, eclogites, amphibolitized eclogites, and garnetites. In this review, first a brief history of the term eclogite and its origin for understanding the process of eclogite formation is presented. Then, a description on the occurrence of various metabasites/eclogites outcrops in the western Himalaya is given. Later, detailed petrological and textural features observed in hand specimen and under the microscope are discussed for individual rock types. Finally, an overview of the Himalayan metabasites tracing back from their magmatic basaltic source to their transformation into amphibolites and eclogites via multi-stage metamorphism is provided. The field features, with the aid of petrological and geochemical evidence of these metabasites, help to constrain the tectono-metamorphic evolution of the continent–continent collision type orogenic belts such as the India–Asia collision-related Himalayan metamorphic belt.

The Juzzak Sill occurs in the western part of the east-west trending, subduction-related magmatic belt known as the Chagai arc. The sill is concordantly emplaced in the Paleocene Juzzak Formation and locally cross-cuts the Early to Middle Eocene Robat Limestone and Eocene Saindak Formation. The sill is a porphyritic pyroxene diorite that grades into a porphyritic andesite (60.12–61.57 wt% SiO2) along the chilled margins. It comprises phenocrysts of hypersthene and plagioclase (An32–45) in a medium- to fine-grained groundmass of these minerals, opaque oxide, and apatite. The rocks are high-K (2.37–2.86 wt% K2O) calc-alkaline with low Mg# (42–55), Cr (51–80 ppm), and Ni (22–30 ppm) contents. Mantle-normalized trace element patterns, exhibited by marked negative Nb anomalies and positive spikes for Sr, Rb, and Zr and are akin to island arc signatures. The relatively higher ratios of Zr/Y (3.57–6.58), Ti/V (46.05–54.36), Ta/Yb (0.14–0.15), and Th/Yb (2.56–2.65) and high 87Sr/86Sr ratio (0.70524) suggest the role of continental crust materials, thus implying continental margin-type arc affinity. The source diagnostic ratios including K/Ba, P/Zr, and La/Ce of Juzzak Sill andesite and Eocene andesite from the Chagai arc are more or less similar, but the former has a much higher K/Y and Ba/Y ratios, which suggests assimilations of the host sediments during intrusion.

The Kohistan arc terrane comprises an intra-oceanic island arc of Cretaceous age separating the Indian plate to the south from the Karakoram (Asian) plate to the north within the Indus suture zone of north Pakistan. The intra-oceanic arc volcanics (Chalt, Dras Group) were built on a foundation of dominantly mid-ocean ridge basalt (MORB)-related amphibolites of the Kamila Group. The subarc magma chamber is represented by multiple intrusions of a huge gabbro-norite complex (Chilas complex), which includes some ultramafic assemblages of residual mantle harzburgite and dunite, layered cumulates, and hornblendites cut by late stage dikes of hornblende + plagioclase pegmatites. The Chilas complex norites intrude the Gilgit metasediments of lower amphibolite and greenschist facies in northern Kohistan, which also form xenolithic roof pendants within the top of the Chilas complex. Along the southern margin of Kohistan, Jijal and Sapat complex ultramafics (dunites, harzburgites and websterites) form remnant suprasubduction zone ophiolitic mantle rocks along the hanging wall of the Main Mantle Thrust, the Cretaceous obduction plane along which Kohistan was emplaced onto Indian plate rocks. Garnet granulites of the Jijal complex, formed at 12–14 kbars, represent original magmatic lower crustal rocks subducted to depths of at least 45 km and metamorphosed during high-pressure and high-temperature subduction of earlier arc-related rocks. Obduction of the Sapat ophiolite and Kohistan arc occurred between ∼75 and 55 Ma. The closure of the Shyok suture zone separating Kohistan from the Karakoram plate must have occurred prior to 75 Ma, the age of the Jutal basic dikes which crosscut the closure-related fabrics, mainly late north directed backthrusting in the lower Hunza valley. Andean-type granitoid (gabbrodiorite-granodiorite-granite) emplacement along the Kohistan-Ladakh batholith ended at the time of India-Asia collision, ∼ 60–50 Myr ago. Postcollisional crustal thickening along the Karakoram led to multiple episodes of metamorphism from latest Cretaceous and throughout the Tertiary. Sillimanite grade metamorphism in Hunza was actually pre-India-Asia collision and may have resulted from the earlier Kohistan collision. Localized and sporadic crustal melting episodes across northern Kohistan (Indus confluence and Parri granite sheets) and the southern Karakoram (Hunza dikes and Sumayar and Mango Gusar leucogranites) occurred from 51 to 9 Ma and culminated in the huge Baltoro monzogranite-leucogranite intrusion 25–21 Myr ago. A vast network of leucogranitic and pegmatitite dikes containing gem quality aquamarine + muscovite ± tourmaline ± garnet ± biotite quartz are younger than 5 Ma and form the final phase of intrusion in the Haramosh area and parts of the southern Karakoram area.

The Raskoh arc is about 250 km long, 40 km wide and trends in an ENE direction. The oldest rock unit in the Raskoh arc is an accretionary complex (Early to Late Jurassic), which is followed in age by Kuchakki Volcanic Group, the most wide spread unit of the Raskoh arc. The Volcanic Group is mainly composed of basaltic to andesitic lava flows and volcaniclastics, including agglomerate, volcanic conglomerate, breccia and tuff, with subordinate shale, sandstone, limestone and chert. The flows generally form 3–15 m thick lenticular bodies but rarely reach up to 300 m. They are mainly basaltic–andesites with minor basalts and andesites. The main textures exhibited by these rocks are hypocrystalline porphyritic, subcumulophyric and intergranular. The phenocrysts comprise mainly plagioclase (An 30–54 in Nok Chah and An 56–64 in Bunap). They are embedded in a micro-cryptocrystalline groundmass having the same minerals. Apatite, magnetite, titanomagnetite and hematite occur as accessory minerals. Major, trace and rare earth elements suggest that the volcanics are oceanic island arc tholeiites. Their low Mg # (42–56) and higher FeO (total)/MgO (1.24–2.67) ratios indicate that the parent magma of these rocks was not directly derived from a mantle source but fractionated in an upper level magma chamber. The trace element patterns show enrichment in LILE and depletion in HFSE relative to N-MORB. Their primordial mantle-normalized trace element patterns show marked negative Nb anomalies with positive spikes on K, Ba and Sr which confirm their island arc signatures. Slightly depleted LREE to flat chondrite normalized REE patterns further support this interpretation. The Zr versus Zr/Y and Cr versus Y studies show that their parent magma was generated by 20–30% melting of a depleted mantle source. The trace elements ratios including Zr/Y (1.73–3.10), Ti/Zr (81.59–101.83), Ti/V (12.39–30.34), La/Yb N (0.74–2.69), Ta/Yb (0.02–0.05) and Th/Yb (0.11–0.75) of the volcanics are more consistent with oceanic island arcs rather than continental margin arcs. It is suggested that the Raskoh arc is an oceanic island arc which formed due to the intra-oceanic convergence in the Ceno-Tethys during the Late Cretaceous rather than constructed on the southern continental margin of the Afghan block, as claimed by previous workers. It is further suggested that the Semail, Zagros, Chagai–Raskoh, Muslim Bagh, and Waziristan island arcs were developed in a single but segmented Cretaceous Ceno-Tethyan convergence zone.

A shallow-focus (3.8 km deep) and low-magnitude (M L 3.8) earthquake occurred near Sheikhupura on August 08, 2010. Shaking was felt in parts of Potwar and northern Punjab but no associated damage has been reported. Tectonically, this earthquake occurred to the south of the Salt Range in the Punjab Seismic Zone (PSZ), a shallow-focus, moderate-level seismic zone characterized by steeply dipping strike-slip and extensional faults. The focal mechanism solution, using the seismological data of the United States Geological Survey and local observatory, shows an EW-trending fault plane dipping 710 N similar to the normal faults reported in the area previously. On the basis of the imposition of the stress field on the northward-moving Indian plate and the nature of the FMS of the previous and this earthquake, the Sheikhupura earthquake is considered as one of the intraplate earthquakes occurring frequently in the PSZ. The location of the event on the Bouguer gravity maps coincides with the zone of high gravity anomaly reflecting igneous intrusion(s) or, more likely, structural disturbances (i.e., extensional faulting in the basement).

Basaltic pillow lavas from near the Muslim Bagh town in northern Balochistan are found in the tectonic slivers of the Bagh Complex, northwest of Muslim Bagh Ophiolite. These volcanic rocks are mainly basanites and tephrites. Their petrography and chemistry suggest that these belong to the mildly–strongly alkaline, intra-plate volcanic rock series. Their low Mg # and low Cr, Ni, and Co contents suggest that the parent magma of these volcanic rocks was not directly derived from a partially melted mantle source but have been modified by fractionation en route to eruption. Their primordial mantle-normalized trace element patterns show enrichment in large ion lithophile elements (LILE) and in high field strength elements (HFSE), with marked positive Nb anomalies, and further confirm their within-plate geochemical signatures consistent with an enriched mantle source. Modeling of their Zr versus Zr/Y trends suggest that these volcanic rocks were derived from about 10–15 % melting of an enriched OIB-style mantle source. It is suggested that these Late Cretaceous intra-plate volcanic rocks may represent the mantle plume activity possibly of the Reunion hotspot. These may have erupted on the Ceno-Tethys Ocean floor prior to the passage of Indian plate over it with subsequent tectonic imbrication during Ceno-Tethyan closure and collision with the Eurasian margin.

This paper deals with the data obtained from local networks in northern Pakistan for 251 earthquakes of magnitude ≥4.0 for October 8, 2005 to December 31, 2006 period. The study presents focal mechanism solutions (FMS) of 12 pre- (1904–2005) and 17 post- (October 8, 2005–December, 2005) Muzaffarabad Earthquake, their detailed tectonic interpretation, and correlation with surface evidence of co-seismic rupture with published synthetic aperture radar data. Distribution of landslides obtained from National Engineering Services of Pakistan and the earthquake damages are also discussed. Aftershock distribution, which is more prominent in the crystalline zone (northwest of Muzaffarabad), defines a 50-km-wide NW–SE trending zone that extends for 200 km from the main mantle thrust to the center of the Hazara–Kashmir Syntaxis. The FMS of the main shock and 16 aftershocks having magnitude ≥4.0 indicate thrusting to be the dominant mechanism with rupture planes having NW–SE trend and NE dip. In addition, 12 FMS of pre-Muzaffarabad Earthquake (1904–2004) from the same area have been determined and results are compared. This leads to the conclusion that the wedge-shaped NW–SE trending blind zone, referred to by earlier workers as the Indus Kohistan Seismic Zone (IKSZ), has been activated during the Muzaffarabad earthquake. The right-lateral component in all FMS, supported by the surface evidences, suggests the involvement of Balakot–Bagh Fault (BBF). We propose that the IKSZ is the source of the October 8, 2005 Muzaffarabad earthquake that reactivated the BBF. Furthermore, the IKSZ does not end at the nose of the syntaxis but extends further southeast of it. Tectonic complexity seems to be due to a variety of factors. Also, thrust and reverse solutions near the northern collisional boundary (main mantle thrust) have mostly NE/SW-directed P-axis orientations. From the detailed FMS analysis, three conclusions have been drawn: (1) Shallow events (depth ≤10 km) with prominent strike slip solutions (earlier earthquakes) are associated with the surface strike slip faults (e.g., Muzaffarabad Fault) and/or the Besham domal structure; (2) moderate depth events (depth 10–25 km) with thrust/reverse solutions but having minor right-lateral strike slip component (all Muzaffarabad earthquakes and two earlier) are associated with the IKSZ; (3) deeper earthquakes (depth below IKSZ) with pure thrust/reverse solutions may be related to the under-thrusting of the Indian plate beneath the IKSZ, which represents a major thrust zone. Imbricate thrusting and breaking and thickening of the crust are considered to be caused by steep bending of the under-thrusting plate at the collisional boundary.

The Seismic Hazard Assessment (SHA) based on probabilistic approach has been carried out for the entire seismically active NW Himalayan Fold and Thrust Belt in Pakistan. Additional information in the form of earthquake catalog, delineation of 41 active faults in a structural map, their relationship to the seismicity, and establishment of seismotectonic zones has also been undertaken. From the distribution of the 813 events within the study area, it appears that seismicity (≥4.0 Mw) is associated with both surface and blind faults. The clustering of events in specific parts along the surface faults shows that some fault segments, especially in the hinterland zone, are more active. In parts of the active deformational front, like the Salt Range, southern Potwar and Bannu, lesser seismic activity (≥4.0 Mw) could be due to damping effect of the thick Precambrian salt. A majority of the earthquakes (86%) range in magnitude from 4.0 to 4.9 Mw, followed by 107 events (13%) ranging from 5.0 to 5.9 Mw. The remaini...

The Indian Plate and Kohistan Island Arc are juxtaposed to the north of Peshawar along the Indus Suture, which is characterized by a tectonic melange consisting of ultramafic, mafic, and a variety of sedimentary rocks. Within metavolcanic greenstones, there are small, lensoid bodies comprising quartz, white mica (up to 4.5 wt% FeO), chlorite (pseudothuringite to ripidolite), pyrite, and abundant chloritoid (up to 60%) and ilmenite. These lenses consist essentially of SiO 2 , TiO 2 , Al 2 O 3 and iron oxide. There is a clear petrographic and geochemical (major, trace and RE element) transition from these rocks to their host greenstones, suggesting a common parentage. The greenstones contain high TiO 2 , Fe 2 O 3 and P 2 O 5 . Their chondrite-normalized patterns show enrichment in light REE, depletion in heavy REE, negative Eu and positive Yb anomalies. Because the greenstones have probably been altered, the present set of data is not capable of deciphering the tectonic setting of these rocks, but previous geochemical studies have suggested an island arc setting for volcanic rocks in the melange. By chemical analogy with lateritized basalts, the chloritoid-rich rocks are considered to be the product of weathering of basalts in tropical, probably equatorial, conditions before the northward drift of Kohistan. Melange formation and greenschist facies metamorphism occurred during the collision of the Indian Plate and the Kohistan Magmatic Arc, to its north, in the Late Cretaceous-Early Tertiary.

The Waziristan Ophiolite is located in the suture zone between the Indian Plate to the east and Afghan Block to the west. It is highly dismembered and divisible into three main sheets or nappes, which from east to west are: the Vezhda Sar Nappe, entirely comprised of pillow basalts; the Boya Nappe, made up of ophiolitic melange with an intact section in its basal part; and the Datta Khel Nappe, consisting mainly of sheeted dykes with smaller proportions of other components. Faunal evidence suggests that the ophiolite is of Tithonian-Valanginian age. It was thrust over the Mesozoic shelf-slope sediments of the Indian Plate to the east during the Paleocene and is unconformably overlain by sedimentary rocks of Early to Middle Eocene age to the west. Beside the sheeted dykes, best exposed in the hanging wall of the Datta Khel Thrust ENE of Datta Khel, the ophiolite also contains isolated dykes. These are doleritic and basaltic in composition. The dykes contain high Na 2 O contents and high FeO t /MgO and LILE/HFSE ratios, and low TiO 2 ( 2 O contents. Non-depletion of Nb and high LILE/HFSE ratio negate, respectively, an island-arc or mid-ocean ridge setting for these dykes. Enrichment in the LILE suggests the involvement of a crustal component driven by fluids along the subduction zone. Several geochemical parameters suggest that the dykes of Waziristan Ophiolite have transitional characteristics between mid-ocean ridge basalt and island-arc tholeiite. It is therefore proposed that these dykes may have originated in a back-arc basin tectonic setting.

Within the syntaxial bends of the India-Asia collision the Himalaya terminate abruptly in a pair of metamorphic massifs. Nanga Parbat in the west and Namche Barwa in the east are actively deforming antiformal domes which expose Quaternary metamorphic rocks and granites. The massifs are transected by major Himalayan rivers (Indus and Tsangpo) and are loci of deep and rapid exhumation. On the basis of velocity and attenuation tomography and microseismic, magnetotelluric, geochronological, petrological, structural, and geomorphic data we have collected at Nanga Parbat we propose a model in which this intense metamorphic and structural reworking of crustal lithosphere is a consequence of strain focusing caused by significant erosion within deep gorges cut by the Indus and Tsangpo as these rivers turn sharply toward the foreland and exit their host syntaxes. The localization of this phenomenon at the terminations of the Himalayan arc owes its origin to both regional and local feedbacks between erosion and tectonics.

The Kohistan island arc terrane is sandwiched between the collided Indian and Karakoram plates in the Himalaya of North Pakistan. Structures related to collision, during which the arc was thrust onto the leading edge of continental India along the Main Mantle Thrust, have resulted in exposure of an almost complete section of arc crust. Mapping along a transect across the east end of the arc terrane provides new data concerning the magmatic emplacement of several of the principal units. The base of the arc here is occupied by a major stratiform ultramafic–gabbroic complex, the Sapat complex. This was intruded into the base of a thick pile of meta-volcanic rocks which make up the Kamila amphibolite belt, and which comprise a varied sequence of basalts some with MORB-type tholeiitic affinities and some with island-arc tholeiitic affinities as well as calc-alkaline andesites. Ultramafic and gabbronorite rocks of the Chilas complex are intrusive into the top of the Kamila amphibolite belt. The upper part of the crust comprises meta-sediments and meta-volcanic rocks of the Jaglot and Yasin-Chalt Groups. These were formed in one or more arc-related basins, and host much of the Kohistan batholith. A three-stage history of crustal thickening can be documented for the Kohistan arc. From its initiation at ca. 125–120 Ma until ca. 90 Ma, the arc grew downward through magmatic emplacement, into its base, of stratiform ultramafic–gabbroic plutonic complexes, and upward through extrusion of volcanic sequences. In Stage 2, the focus of crustal growth shifted upwards from the base of the arc with emplacement of the Chilas complex along the interface between the Kamila amphibolite belt and the overlying volcano-sedimentary cover. This stage of crustal thickening was accompanied by shortening associated with the 90–80 Ma Kohistan–Karakoram collision. Finally, in Stage 3 (80–45 Ma), the Kohistan batholith was emplaced into deformed cover rocks of the uppermost part of the arc crust.

A thick succession of metasedimentary and metavolcanic rocks has been reported for the first time in the Gilgit area. This succession (the Jaglot Group) comprises from bottom to top 1) the Gilgit Formation, 2) the Gashu Confluence Volcanics, and 3) the Thelichi Formation. The Gilgit Formation consists of thick turbiditic sediments interstratified with amphibolites and calc-silicates. The lower contact of the formation is not exposed, but presumably underplated by the Chilas Complex, and the upper contact is conformable with the Gashu-Confluence Volcanics. The Gilgit Formation contains more than 80% paragneisses and schists showing metamorphism up to the sillimanite grade. The paragneisses are strongly deformed and at places migmatized. The paragneisses of the Gilgit Formation are quartz rich, but also contain biotite, garnet, staurolite, kyanite, sillimanite, graphite, together with pyrite and magnetite. Petrographical and geochemical data show that they are metapelites, semi-metapelites and semi-metapsammites. Using geothermometry and geobarometry on garnet-biotite pairs, the estimated maximum temperature and pressure conditions are 640°C and 6.7 kbar, respectively. We assume that igneous intrusions, both the Chilas Complex and the Kohistan Batholith and crustal thickening accompanying arc accretion to the Karakoram plate might have ensued metamorphism in the Gilgit Formation and other lithological units of the Jaglot Group. As depicted by the chemical zonation profiles of garnets in two samples from Jutial, the grade of metamorphism in the metasediments of the Gilgit Formation seems to increase from top to bottom in a normal sequence. The field and laboratory studies show almandine amphibolite subfacies and sillimanite-almandine amphibolite subfacies metamorphic conditions for the Gilgit Formation, and ocean basin of a back-arc affinity for its deposition.

New field mapping and structural data, combined with published geochemical data, from the Kohistan arc in the NW Himalaya, enable a re-evaluation of the arc stratigraphy. Key lithological units and their relationships are more clearly defined, permitting the construction of a revised magmatic-tectonic history for the arc. The oldest units are transitional oceanic-type basalts, which form the basement to the subduction related sequence. Arc-type gabbroic sheets and plutons intrude the oceanic basalts: together these form the Kamila Amphibolite Belt. Metasediments and basaltic lavas were deposited, within an extensional basin, onto the Kamila Amphibolite Belt basement. This sequence, exposed across the arc, forms a distinct stratigraphic unit which is formally defined here as the Jaglot Group. Sediment-charged turbidity currents transported material into the basin, whilst submarine eruptions contributed the basaltic component. This period of extension culminated in the eruption of high-Mg boninites of the Chalt Volcanic Group which overlie the rocks of the Jaglot Group. The earliest granitoids of the Kohistan Batholith predate suturing and intrude the Jaglot and Chalt sequences. At c. 100 Ma Kohistan sutured to Asia. suturing being accompanied by thickening of the arc with the development of major intra-arc shear zones and a penetrative, regionally developed steep cleavage. At c. 85 Ma intra-arc rifting permitted the emplacement into the arc of the voluminous gabbronorites of the Chilas Complex which clearly intrudes the Kamila Amphibolite Belt to the south and the Jaglot Group to the north. The Chilas Complex has been regarded as part of the pre-suturing, juvenile arc sequence. Field evidence summarized here show this to be not so. Heat advection associated with emplacement of the Complex caused amphibolite facies regional metamorphism, melting of the lower arc and plutonism. Some of the resultant granitoid plutons were unroofed and eroded during a compressional phase at between 80 and 55 Ma, before emplacement of further plutons and extrusion of basaltic through to rhyolitic volcanic rocks at between 55 and 40 Ma. At least three phases of extension and rifting, each separated by short lived phases of compression, charac­terized arc evolution. Much of the magmatism is controlled by extensional tectonics within the overriding plate of the kind commonly associated with a retreating subduction zone.

The east central part of the Kohistan magmatic arc is made up principally of the Jaglot Group. From bottom to top it consists of I) paragneisses and schists intercalated with amphibolites and calc-...

The suture zones bordering the Indian subcontinent on the E, N and W are characterized in several places by the occurrence of ophiolitic complexes and tectonic melanges. High-P metamorphic rocks have recently been discovered in the melanges in Burma, Naga Hills, southern Tibet, eastern and western Ladakh, Kohistan (Jijal, Allai, Shangla) and Khost (Afghanistan). The development of these rocks has an important bearing on the plate tectonics of the Himalaya. The High-P metamorphic rocks belong to prehnite-pumpellyite, blueschist and high-P greenschist facies but extensive garnet-granulites have developed at 35 km depth in Jijal. In the Indus-Zangbo suture zone (IZS) the high-P metamorphism is complemented to the N by low- or medium-P metamorphism and calc-alkaline magmatism in Tibet, Ladakh as well as Kohistan. High-P metamorphism in Jijal has been dated at 104 Ma, in Shangla at 70–100 Ma and in western Ladakh during mid-Cretaceous. Elsewhere, the timing of the high-P metamorphism is not known but a Cretaceous age is inferred. Since collision along the IZS occurred during Eocene, the high-P metamorphism is therefore related to the northwards subduction of the neo-Tethyan lithosphere under Tibet or late Mesozoic magmatic arcs. The timing of high-P metamorphism coincides with the breakup of India from Gondwanaland and its rapid northwards movement, whereas the tectonic melanges may principally have formed during Eocene collision and obduction.

The western margin of the Indian plate is a classical example of continent-continent collision. The Afghanistan-Kabul-India continental blocks are here welded to each other by a network of sutures defined by the occurrence of ophiolites. The Waziristan Ophiolite (WO) is one of a series of ophiolites sandwiched between the western margin of the Indian plate and Afghanistan block. It is highly dismembered, but contains all the segments of an ideal ophiolite suite. It can be internally divided into three nappes which, from east to west, are: Vezhda Sar nappe, comprising entirely of pillow basalts; Boya nappe, a tectonic melange with an intact ophiolite section in the basal part at Mami Rogha; and Datta Khel nappe, consisting of sheeted dykes with variable proportions of other components. The intact ophiolite section consists of 1) basal ultramafics followed upward by 2) isotropic gabbros, and 3) pillow basalts, intercalated with and capped by pelagic sediments (chert, shale, limestone) (Figure 1). Isolated mafic dykes (doleritic), characterised by chilled margins, intrude all types of ophiolitic rocks, except the pillow basalts of Vezhda Sar nappe. Trondhjemites mostly intrude the ultramafics and rarely gabbroic rocks. Layered gabbros, missing in the ophiolite section, are sporadically distributed as fault-bounded blocks in the two western nappes.

The Kohistan Magmatic arc started building during the Early Cretaceous as an intra-oceanic island arc thousands of kilometers to the south of its present position. It was welded to the Karakoram plate along the Shyok suture during the midCretaceous, after which it became an Andean-type continental margin. Collision with India along the Indus suture occurred during the Early Eocene. The Kohistan arc exposes a complete section across the crust and consists of a range of variably metamorphosed plutonic, volcanic, and subordinate sedimentary rocks. The lower crust in Kohistan is represented by a series of mafic to ultramafic rocks. These include the granulite facies metamorphosed Jijal complex, which covers 150 sq km area of the southern fringe of the arc along the Indus River. Relics of similar rocks in amphibolites also occur 35 km to the southwest, north of Shangla. The southern (structurally lower) part of the Jijal complex in the hanging wall of the Indus suture comprises chromite-layered dunites, peridotites, and pyroxenites. These pass upwards into garnet-bearing ultramafic and mafic granulites. The transition zone contains pyroxenites (±Grt) or peridotites showing the development of garnet at the interface of plagioclase and opaque oxide /olivine. The main bulk of the granulites is represented by the assemblage Grt+Px+Pl+Qtz+Rt±Hbl. These rocks are mostly homogeneous, but locally well-layered. In addition to the principal assemblage, the layers comprise garnet pyroxenites (Cpx ± Opx ± Hbl), garnetites (±Cpx±Pl±Hbl), and metaanorthosites represented by the assemblages Pl+Grt+Cpx+Scp and (Zo+Grt±Cpx±Hbl±Qtz). The northern part of the complex contains relics of gabbronorites/pyroxene granulites (Pl+Opx+Cpx+Hbl+Ilm+Mag) protolith. The garnet granulites here invade the protolith in networks of veins and patches that appear to have formed along joints and fractures due to release of H2O during compression (increasing load pressure and temperature). Field data, combined with petrographic study and mineral analysis, suggest the following reaction for the transformation: Pl(An45)+Opx(En62)+Cpx(Mg 33.8, Fe 18.6, Ca 47.6; Al2O3 7.2%, Na2O 1.8%)+Prg=Pl(An48)+Grt(Mg 31.7, Fe 44.9, Ca 23.4)+Cpx(Mg 37.7, Fe 13.0, Ca 49.2; Al2O3 5.6%, Na2O 1.6%)+Rt+Qtz. Jan et al. (1997) and Yamamoto and Yoshino (1998) showed that this transformation was isochemical for major elements. Further XRF data (Table 1) show that apart from a loss in soda, the major and trace elements remained immobile during the pyroxene-granulite to garnet granulite transition. When normalized to primordial mantle values, the analyses of the mafic granulites display island arc signatures (Figure 1).

The southern part of the Cretaceous Kohistan island arc is occupied by an extensive belt dominantly comprised of amphibolites. These include banded amphibolites of partly meta-volcanic parentage, and non-banded amphibolites derived from intrusive rock. In addition to being relict, banding has also been produced by shear deformation, metamorphic/metasomatic segregation and, possibly, by lit-par-lit injection of plagiogranitic material. Non-banded amphibolites also occur as retrograde products of noritic granulites forming the lopolithic Chilas complex. The chemistry of 37 rocks has been compared with those of known tectonic environments. The amphibolites have chemical characteristics similar to volcanic rocks found in island arcs and most of the analyses apparently support affinity with the calc-alkaline series. The amphibolites consist essentially of hornblende, plagioclase and/or epidote. Garnet and clinopyroxene have developed locally in rocks of appropriate bulk composition. Metamorphism may have taken place during the mid-Cretaceous under conditions of 550 to 680°C and 4.5 to 6.5 kbar PH2O. The metamorphic grade appears to increase from the centre of the southern belt toward the Chilas complex to the north and Indus-Zangbo suture (IZS) to the south. In the vicinity of the IZS, garnet-clinopyroxene ± amphibole assemblage developed locally in response to high P-T.

The Waziristan complex, covering over 500 km 2 , was tectonically emplaced during the Paleocene to early Eocene. It consists of ultramafic rocks, gabbros, sheeted dikes, pillow lavas, and pelagic sediments--a typical ophiolite suite. However, a complete sequence does not occur in any single locality due to tectonic dismemberment. The podiform chromitites consist of aluminochromite (Cr 2 O 3 :49-61%) with subordinate chromian chlorite and/or chromian serpentine + magnetite. In Cr-Al-Fe (super +3) + Ti space the chromites plot in the area of alpine chromites, but on other diagrams they overlap the fields of chromites from alpine and stratiform complexes. Many chromites are zoned with "ferrit-chromit" margins richer in Cr/(Cr + Al) and poorer in Mg/(Mg + Fe (super +2) ) than the unaltered cores. The chlorites are generally rich in SiO 2 and MgO and poor in Al 2 O 3 . It appears that during greenschist facies metamorphism (or alteration) diffusion of Mg, Al, and some Cr from the chromite margins toward the silicate matrix resulted in the development of ferrit-chromit and chlorite.

SummaryThis paper presents wet chemical analyses of forty-one pyroxenes (thirty-nine of them new) from pyroxene granulites and a few neighbouring rocks from Swat Kohistan and the adjoining Indus Valley. The granulites, considered to be derived from plutonic norites of an island arc tholeiitic nature, constitute one of the most extensive belts of its kind in the world. The pyroxenes are not unusual in any respect but they bear a closer resemblance to metamorphic than to igneous pyroxenes crystallized from deep-seated tholeiitic magmas. The distribution of Mg, Fe, and Mn (average KDMg−Fe=0.57) and the tie-line intersections on the Wo-En join (generally from Wo80.5 to Wo76.5) between the coexisting eighteen pyroxene pairs from the granulites are discussed. Based on eight different methods of geothermometry and other considerations, it is concluded that the pyroxene granulites were metamorphosed at around 800 °C and 7 to 8 kbar.

Orbicular dioritic-noritic rocks from an area of mixed metemorphic and igneous rocks in Swat Kohistan, northern Pakistan, have been examined petrographically and chemically in order to determine the nature and origin of the orbicular texture. Using textural and compositional sequences it has been possible to relate the apparently different orbs to one another, and obtain a sequence of orb formation. The majority of the orbs comprise a series of distinct layers (shells) surrounding a central zone (core). Plagioclase, clinopyroxene, orthopyroxene and hornblende form the bulk of the shells. The cores have been extensively recrystallized. The development of a ‘comb-layered’ texture in some orbs and in associated layered rocks is comparable to that commonly described from other occurrences. A dual igneous/metasomatic crystallization history is invoked to explain the features of the orbs in this locality, the oscillatory zoning of the orbicular structure being caused by the alteration of primary minerals, such as pyroxene to amphibole, due to fluctuations in the pH2O of the magma.

SummaryA series of metamorphosed (amphibolite facies) basic and intermediate igneous rocks from upper Swat, Pakistan, is described, with seven chemical analyses. The rocks intrude ?Palaeozoic metasediments and are partially bordered by other, later, intrusive and volcanic rocks. The group, now represented by, from S–N, epidote amphibolites, amphibolites, noritic and hypersthene gabbros, and quartz diorites, is considered to be derived from a series of plagioclase hypersthenites, norites, hypersthene gabbros, and hypersthene diorites. Variation diagrams are used to show that the series forms a differentiated sequence; FMA and lime-alkali diagrams suggest that it is similar to the rocks of the Garabal Hill–Loch Fyne area of Scotland. Some of the mineralogy of the group is briefly discussed, with five chemical analyses. A K/Ar age determination gives 67 Ma; thus the rocks probably derive from an early Himalayan (Alpine) tholeiitic basalt magma.

SummaryAlkaline microgranites and granite, containing aegirine, riebeckite and astrophyllite, from north-west Pakistan, are briefly described, and tentatively correlated with other alkaline rocks in the region.

SynopsisColourless, purple, and pink topaz and transparent quartz crystals have been found in calcite veins (with or without milky quartz) in calcareous rocks near Katlang (34° 24′ N, 72° 6′ E), Mardan district. The veins do not contain any fluorite nor the country rocks any topaz. The topaz and transparent quartz crystals are mostly broken and perfectly euhedral outlines are very rare. Refractive indices, 2V, specific gravity, and the fluorine (determined) and H2O + (calculated) contents of two topaz crystals are suggestive of their high 100 OH/(OH+F) ratios (> 25). Rather than being derived, the topaz may have formed in situ by hydrothermal/pneumatolytic activity, followed by tectonic movements that fractured the crystals and resulted in their incorporation in later-formed vein calcite.