Main Thrust Research Articles

Zircon U–Pb, Hf, and O isotopic constraints on the tectonic affinity of the basement of the Himalayan orogenic belt: Insights from metasedimentary rocks, orthogneisses, and leucogranites in Garhwal, NW India

Zircon U–Pb geochronology and Hf–O isotope geochemistry of metasedimentary rocks, orthogneisses, and leucogranites in Garhwal, NW India, provide new insights into the tectonic affinity of the basement of the Himalayan orogenic belt. Detrital zircon U–Pb ages from metasedimentary rocks in both the Lesser Himalayan Sequence (LHS) and the overlying Main Central Thrust (MCT) zone yielded dominant Paleoproterozoic ages with the youngest age peak of 1840 Ma. Along with that, the variable ɛHf (t) values (−14.56 to 8.44) indicate that these metasedimentary rocks could have been derived from the juvenile Paleoproterozoic orthogneiss basement in the Himalayas and/or the ancient Indian craton in the south. In contrast, the metasedimentary rocks in the Ediacaran Harsil Formation are dominated by the ca. 1200–800 Ma zircons with the youngest age peak of ca. 630 Ma and variable ɛHf (t) values (−16.57 to 13.32), which belong to the underlying High Himalayan Crystalline Sequence (HHCS), rather than the overlying Tethyan Himalayan Sequence. Orthogneisses in the MCT zone record ca. 1.87–1.85 Ga felsic magmatism associated with the Nuna supercontinent. The Bhagirathi leucogranites intruding the Harsil Formation were formed at ca. 496–490 Ma. These Paleoproterozoic orthogneisses and early Paleozoic leucogranites show only positive ɛHf (t) values (0 to +15) correlatable with a juvenile mantle input. However, the zircon Hf model ages older than the U–Pb ages and the oxygen isotope values (δ18O: 7.74–8.91 ‰), significantly higher than zircons crystallized from mantle-derived magma, indicate large degrees of melting and contamination of crust materials in both the granitoids. In combination with the pre-existing geochronological data, the current study indicates that the Garhwal HHCS is characterized by bimodal Neoproterozoic zircons at ca. 1100–900 Ma and ca. 860–800 Ma with wide εHf (t) values which are similar to those in the outer LHS and the Cathaysia Block (including the Jiangnan Orogen) of the South China Craton. These observations suggest that a close relationship existed between North India and South China during the Neoproterozoic since Tonian. The provenance of the Neoproterozoic HHCS is possibly a mixed source from both southern Gondwana terranes (e.g., east Antarctica) and northern South China.

Slope instabilities and evolution of tectonic geomorphology along the strike of the Main Boundary Thrust zone in the western Himalaya, India

The Main Boundary Thrust (MBT) and Main Boundary Fault (MBF) zones of the southeast Himachal Himalaya are susceptible to various types of mass movement. Several active and in-active landslides are observed along the strike of the MBT. The landslides are mainly controlled by the brecciated and highly fractured nature of the bedrocks, and the intersecting joint sets form wedges. The movements are taking place along the fault planes, fracture planes, and bedding planes; and the types of failure are wedge failure, planar failure, toppling, rock falls, and complex landslides. The various morphotectonic features observed in the study area include fault traces, fault scarps, strath terraces, paleochannels and structurally controlled channels. Fault traces and their associated deformed landforms are the most spectacular tectonic landforms in the area. Along the strike length of the fault traces several linearly arranged sag ponds have formed, in the western segment the fault trace is observed along the MBF and the fault scarp dips south, with a maximum height of about 34 ​m. In the eastern segment the fault trace cut across the MBT, the fault trace is also displaced by transverse faults. Paleochannels and multiple levels of strath and fill terraces collectively indicate the river channel's disequilibrium state concerning the ongoing tectonic activity. The cross-cutting relation and displacement pattern of fault traces indicate later phases of tectonic activity.

MIDWIVES POPULATION AND ANTENATAL CARE (ANC) SERVICE PROVISION IN CROSS RIVER STATE, NIGERIA: A QUANTITATIVE-QUALITATIVE APPROACH

The main thrust of this study was to assess midwives’ population and service provision at Primary Health Care level in Cross River State, Nigeria. To achieve this objective, two research questions and one hypothesis was postulated to guide the study. The adopted design for this study is a concurrent triangulation mixed method design, which utilizes both quantitative and qualitative approaches. The sample comprised of 70 mid-wives for the quantitative approach and 8 mid-wives for the qualitative approach through the use of census and purposive sampling techniques respectively. A questionnaire developed by the researcher on the type of services provided by mid-wives was used to collect data for the qualitative approach, while a focused group discussion was used to collect data for the qualitative approach. The data gathered were analyzed with descriptive and inferential statistics as well as qualitatively. Results indicated that only forty-four (44) PHCs have midwives while one hundred and fifty-eight PHCs have no midwife at all. The result also indicated that the one PHC that has above 3 midwives render high quality care services to client than the 43 PHC that have below 3 midwives population has the calculated t-value of 17.225 is greater than the critical t-value of 1.980 at 0.05 level of significance and 68 degrees of freedom. This implies that there is a significant relationship between midwives’ population and ANCs service provision in PHCs in Cross River /State, Nigeria. Based on this finding, it was recommended that the presence of midwives in State Primary Health Care Development Agency should be strengthened. Nursing and midwifery council should review the policy to establish community midwifery in Cross River State were more midwives will be trained and automatically employed to PHC level in the State.

Diamond-bearing fluidolites in the junction area of East European Platform and Urals fold region

Research subject. To characterize the Sylva fluidogenic-explosive complex, which was established in the junction area of the West Ural thrust megazone (head of the Sylva River) and the eastern wing of the Yuryuzano-Sylva depression of the Pre-Ural trough. Materials and methods. The authors' materials collected during research works at GSA200/2 sheet O-40-XXIX (Shalinskaya Ploshchad), as well as those collected during the work under the Priority 2030 Federal Program, were used. Data on the geology, petrochemistry, petrography, structural and tectonic position of clastogenic rock associations in the area of influence of the Main West Ural thrust were employed. Experimental data were obtained using a TESCAN VEGA LMS electron microscope equipped with an Xplore 30 energy dispersive X-ray spectroscopic prefix, and an URS-55 X-ray unit (Ural State Mining University), as well as CPM-35 and Shimadzu EDX-8000 spectrometers and an XRD-7000 diffractometer (Geoanalitik Centre, Zavaritsky Institute of Geology and Geochemistry of the Ural Branch of the Russian Academy of Sciences). Results. For the first time, the mineralogical-petrographic and chemical compositions of diamond-bearing rocks of the Sylva fluidogenic complex were established. Diamonds and minerals contained in the studied rocks were determined by XRD (sanidine, analcime, etc.). The conducted analysis of the rocks suggests their possible fluid-magmatic genesis, which is indicated by mineralogical features, including accessory minerals-indicators of diamond content, the presence of ellipsoid and teardrop-shaped volcanic glass, finely-dispersed bulk and poorly-rolled unsorted fragments of igneous and sedimentary rocks. Conclusions. The results obtained indicate the possibility of manifestation of Early Mesozoic phreatic volcanism in the studied area, which led to the transfer of the Sylva diamond complex and accessory minerals by fluidolites.

Distribution of Active Faults and Lithospheric Discontinuities in the Himalayan-Tibetan Orogenic Zone Identified by Multiscale Gravity Analysis

The lithospheric structure of the Tibetan Plateau and its adjacent area is a hot topic in geodynamic research. It is important to reveal the mechanism of crustal deformation and tectonic evolution of the study area. In this study, the techniques of wavelet multiscale decomposition and field edge detection were used to study the discontinuities of the lithosphere revealed by multilevel Bouguer gravity anomalies. Specifically, we evaluated the depth characteristics of the major active faults in the study area and identified 15 deep major faults that cut through the lithosphere. They are Chaman fault, Shyok suture zone, Altyn-Tagh fault, Karakash fault, Karakoram fault, Talas-Fergana fault, Kashgarr-Yeshgar transfer system, Rushan-Pshart suture zone, Sangri-Nacuo fault, Main Frontal thrust, Burmese fold belt, Yadong-Gulu fault, Gaoligong fault, Sagaing fault and Nujiang fault. We have also elucidated the tectonic mechanisms of two famous geodynamic phenomena in the Pamir Plateau. The first is the intense intermediate depth seismicity beneath Pamir-Hindukush. It cannot simply be described as the rupture of a subducted residual plate, which could be divided into two distinct tectonic units. One belongs to the Indian plate, the other to the Eurasian plate. Secondly, the mechanism of intense seismicity confined to the western upper crust of the Pamir Plateau could be explained as significant fragmentation of crustal material. Finally, and most importantly, we summarized the coupling mechanism between deep geodynamics and horizontal deformation as observed by modern geodetic techniques. In the upper mantle, the leading edge of the subducting Indian plate reached the SW boundary of Tarim basin and forms a closed structure in western Himalaya. Then, the Tibetan Plateau underwent a tectonic escape towards the east under the continuous compression between the Indian and Eurasian plates. During the process of tectonic escape, the role of the N–S direction normal faults in the Himalayan tectonic zone is limited.

Tectono-geomorphic and active deformation studies in the Ujh basin of Northwestern Himalaya

This study focuses on the morphotectonic analysis of the Ujh River basin, examining various aspects related to geometrical changes in the drainage basin caused by tectonic and erosional processes. The topographic development of the Ujh River basin is a response to enhanced tectonic deformation caused by Main Central Thrust (MCT) and Main Boundary Thrust (MBT). We assume that the basin asymmetry, tilting, incision, and migration of the river basin are regulated by the compressive force generated between MBT and MCT. The results were characterized by a high Asymmetry Factor (Af) indicating greater asymmetry suggesting a rightward tilting with low Valley Floor to Valley Width (Vf) values which indicate differential uplift and incision owing to ongoing tectonic processes. The high Stream Length Gradient (SL) Index values in the MCT zone, indicate sudden topographic breaks caused by the vertical tectonic uplift with active erosion processes. The Ujh River basin is in a disequilibrium state, with convex portions indicating uplift and concave portions indicating subsidence on the slope-area plot. The χ analysis, plotting χ values against elevation, highlights upliftment and erosion zones along the trunk stream, with major slope breaks and high χ values observed in the upstream region, particularly along the MCT. Overall, the Ujh River basin exhibits morphotectonic characteristics indicating ongoing tectonic activity and a state of disequilibrium.

The Uttarakhand Himalaya: An image of the main Himalayan thrust, Moho, and lithosphere-asthenosphere boundary

We use seismic velocity tomography and Common Conversion Point (CCP) stacked radial PRFs to model the main Himalayan thrust (MHT), Moho, and Lithosphere-Asthenosphere boundary (LAB) beneath the Uttarakhand Himalaya using broadband data from 55 three-component seismographs. The Main Himalayan Thrust (MHT) between 8 and 20 km depth, which our modelling identifies as the source of the majority of the recent micro-earthquake activity, is characterised by larger negative Ps/P amplitudes, a 10-20% drop in Vp and Vs, and a 10-15% increase in Vp/Vs. We simulate a strongly undulating northeast-dipping crust-mantle interface between 30 and 55 km depth (with larger positive Ps/P amplitudes). In addition, we establish a lithosphere-asthenosphere boundary with a northeast-dipping depth between 130 and 180 km (with larger negative Ps/P amplitudes). Both the presence of metamorphic/aqueous fluids and the predicted double Moho structure are hypothesised to result from the continued northward convergence of the Indian plate beneath the most active rupture zone in the Garhwal - Kumaon Himalaya. One possible explanation for the double Moho structure is that the Indian crust and upper mantle became entangled during the collision of the Indian and Eurasian plates. Above the aforementioned rupture zone, where all Mw6.5 events have occurred so far, the upper crust is likely accumulating the strain energy needed to generate moderate to large earthquakes on the MHT.

Geodynamics and Early Cretaceous Magmatism of the Northern Volcanic-Plutonic Belt of Verkhoyan-Kolyma Fold Area (Northeastern Russia)

New data on the geological position, U‒Pb SIMS zircon ages, petro-geochemical features, Sr‒Nd isotopic composition and geodynamic setting of the granitoids and volcanites of the Northern volcanic-plutonic belt, Verkhoyan-Kolyma fold area, are presented. Magmatites of the belt include granitoids of Elikchan, Kuranakh, Bakyn plutons, composed of elikchansky granite-granodiorite complex, and volcanites of predominantly intermediate-felsic Tumusskaya sequence with subvolcanic bodies of the same composition. They form single Early Cretaceous (127–121 Ma) volcanic-plutonic assemblage. Granitoid plutons are elongated in sub-latitudinal-northwestern direction and are discordant to main fold and thrust structures. Granitoids intrude and metamorphose Jurassic terrigenous and Early Cretaceous volcanites of Tumusskaya sequence and are cut by younger Late Cretaceous subvolcanic bodies. Granitoids of Bakyn, Elikchan and Kuranakh plutons combine petro-geochemical features of I-, S- and A-type granites. Such diversity of petro-geochemical granitoid types as well as interrelations of major (\({\text{F}}{{{\text{e}}}_{{\text{2}}}}{\text{O}}_{3}^{{{\text{tot}}}}\)–TiO2–MgO) and rare (Ba/La–Nb × 5–Yb × 10) elements in granitoids and the same age volcanites of Tumusskaya sequence allow to refer them to magmatites of transform margin or plates translation boundaries. Collision between Chukotka microcontinent and Siberian continent with earlier accreted Kolyma-Omolon microcontinent in Barremian-Aptian time changed to post-collisional extension and formation of volcanic-plutonic assemblage of the Northern volcanic-plutonic belt. Post-collisional extension took place in the regime of plates translation boundaries. Sr–Nd isotopic characteristics of granitoids of all plutons indicate the interrelation of mantle and crustal sources of granitoid melts in this process.

An overview of copper ore mineralization in the Nepal Himalaya

Exploration of copper ore in the Nepal Himalayas has been carried out by different researchers at different times. The author conducted detailed geological studies and mineral exploration in some of the copper and polymetallic prospects and also reviewed the literature related to copper prospects in Nepal. The present research is able to delineate two distinct copper ore mineralization belts extending from west to east and identify the promising sites for copper ore and polymetallic mineralization that could be feasible for mining. The northern mineralization belt lies close to the Main Central Thrust where the mineralization occurs mostly in metamorphic rocks of garnet amphibolite facies in Darchula,Bajhang, Gorkha, Dolakha, Solukhumbu and Ilam districts. The southern mineralization belt in the Lesser Himalaya occurs in low-grade metamorphic rocks of greenschist facies in Dadeldhura, Rukum, Baglung, Myagdi, Tanahun, Dhadhing, Makwanpur, Dolakha, Udaypur, Bhojpur and Ilam districts. Most of these prospects were locally exploited on a small scale by traditional mining before 1951. Almost all mineralization in both belts is related to hydrothermal dissemination, irregular multiple vein type, replacement and cavity fillings and only a few polymetallic mineralizations at the exo-contact zone of granite bodies. The ore minerals were concentrated during the processes of regional metamorphism at the time of Himalayan upheaval. In general, the copper content in the northern belt appears to be higher in grade and tonnage as compared to the southern belt. The frequent association of tungsten, molybdenum, bismuth, nickel, tin, lead, zinc ores and traces of gold suggests the urgent need for further detailed exploration and evaluation of selected prospects which could be economic deposits and feasible for mining.

Geological control of terrestrial background radiation in Garhwal Himalaya, India.

Activity concentrations of 226Ra, 232Th, and 40K were measured in soil samples from several areas of Garhwal Himalaya, Northern India, by gamma-ray spectrometry. In this region, which extends around the Himalayan Main Central Thrust, a tectonic line that separates several geological provinces, background levels of natural terrestrial radiation were assessed. The maximum levels of radium, 285Bq/kg and 136Bq/kg, respectively, were found in the Budhakedar and Uttarkashi regions, exceeding the world average value of 35Bq/kg. The mean radiation levels were found to be different between the areas, which reflects the geological diversity in the region. The overall absorbed dose rate owing to radionuclide presence in the Uttarkashi area ranged from 79 to 188 nGyh-1, with an average of 118 nGyh-1. That is more than UNSCEAR's world-populated weighted average value of 59 nGyh-1. The present investigation indicated that the absorbed dose rates are greater in Uttarkashi and Budhakedar than in other places. The multiple comparison analysis between geology and absorbed dose rate shows that the geology of Uttarkashi and Budhakedar are statistically similar. According to several hazard indices, terrestrial background radiation is not of radiological concern in the investigated region.

Recycling of silver nanoparticles from electronic waste via green synthesis and application of AgNPs-chitosan based nanocomposite on textile material

The main thrust of this project is the fabrication of silver nanoparticles (AgNPs) from electronic waste (PCB board) and applying it on 100% cotton fabric as an antimicrobial agent. The nanoparticle formation of silver was done by green synthesis way using an aqueous leaf extract of Eichhornia crassipes. Furthermore, chitosan was also applied to the fabric with silver nanoparticles by coating. FTIR and SEM tests characterized the fabricated silver nanoparticles, and antimicrobial tests were followed by the disc diffusion method. The SEM analysis showed an average particle size of 76.91 nm. The FTIR analysis showed the successful reduction of silver nanoparticles and the bonding with chitosan and cellulose. Besides, the EDX reports confirmed the existence of AgNPs by indicating a strong signal in the silver region. In addition, SEM characteristics analysis confirmed the uniform deposition of silver nanoparticles. Finally, the antimicrobial property was tested against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria. The antimicrobial result was found satisfactory in the case of green-synthesized recycled AgNPs. However, the effectiveness was not observed to be higher than green-synthesized pure AgNPs. In this study, the zone of inhibition of AgNPs was also compared to the reference antibiotics Ciprofloxacin.

Mineral resources of the Gandaki Province of Nepal: present status and prospect

Mineral resources serve as the foundation of prosperity for any country or community. However, the process of prospecting and exploring these resources is time-consuming and involves financial risks. It requires the combined expertise of both geoscientists and mining engineers, encompassing academic knowledge and professional skills. In this research, we provide an overview of the mineral resources within the Gandaki province of Nepal and evaluate their present status. The main objective is to examine the current status and potential of mineral resources in the province. To achieve this, we extensively utilize available reports, journal articles, and online sources. We gather both primary and secondary data on mineralization. Additionally, we systematically list the potential locations of all documented mineral resources within the Gandaki province, along with their GPS coordinates. Based on the current geological and mineralogical investigations, as well as our understanding of the province’s mineral resources, we identify ten minerals or mineral groups with potential economic value: iron, copper, uranium, tourmaline, syenite, thermal springs, limestone, dolomite, slate, and meta-basic rocks like amphibolite. We strive to provide geological evidence and context for supporting the presence of these minerals.
 In general, iron mineralization is observed as sedimentary deposits, exhibiting a syngenetic nature. Many copper ores are hydrothermally deposited originating from the underlying meta-basic rocks like amphibolite. The region is also known for its abundance of gemstones, including quartz crystals, garnet, kyanite, and tourmaline. These minerals are concentrated in the vicinity of the Main Central Thrust zone and its surrounding areas. Moreover, the province has significant potential for high-quality dimension stones for flooring, roofing, and pavements such as quartzite, slate, phyllite, schist, granite, and gneisses. Additionally, there are ample opportunities for the extraction of construction materials like sand and gravel from the river terraces and natural rock outcrops. Nevertheless, a systematic study focused on prospecting, exploration, and utilization of these potential and possible mineral resources is imperative for an accurate economic evaluation. To achieve this, the provincial government must develop plans and policies to facilitate the development of its own mineral resources. Furthermore, establishing strong collaboration between professionals and academia is crucial to make well-informed investments in the mineral sector. Considering the present status of minerals, the Gandaki province of Nepal holds promising prospects for harnessing its mineral resources for sustainable development.

Geological study along Sipaghat-Panchkhal-Sukute area, Kavreplanchowk and Sindhupalchowk districts, Lesser Himalaya, central Nepal

A detailed geological study has been carried out in the Lesser Himalayan rocks distributed in Panchkhal-Dolalghat- Sukute area in Kavre Palanchowk and Sindupalchowk districts. The study area belongs to Kuncha Formation of Lower Nawakot Group, Benighat Slate of Upper Nawakot Group, Nawakot Complex; Raduwa Formation, Bhaisedobhan Marble, Kalitar Formation, Chisapani Quartzite, Kulikhani Formation, and Markhu Formation of Bhimphedi Group and Tistung Formation of Phulchauki Group, Kathmandu Complex. These two complexes are separated by the Main Central Thrust (MCT). Four lithounits of the Lower Nawakot Group (i.e., Fagfog Quartzite, Dandagaon Phyllite, Nourpul Formation and Dhading Dolomite) and two lithological units (Malekhu Limestone, Robang Formation) of the Upper Nawakot Group are missing in the area. The area comprises intercalation of coarse-grained, thick bedded quartzite and gritty phyllite of Kuncha Formation, dark argillaceous slates with Jhiku Carbonate beds including sporadic amphibolite of the Benighat Slate. The Bhimphedi Group of the Kathmandu Complex comprises mainly micaceous schist, marble, metasandstone and augen gneiss whereas the Phulchauki Group comprises of metasandstone and granite. The lithological units strike NW-SE and dip towards south forming the eastern closure of the Mahabharat Synclinorium in the northern limb.

Post Conflict Bakassi and Role of Cameroonian and Nigerian Military

No one would have thought that the military clashes between Cameroon and Nigeria over the Bakassi Peninsula would one day end. For close to 50 years, Cameroon and Nigeria had been fighting over the resource-rich area of Bakassi to take control of it. The mechanisms that resolved these military upheavals were the World Court's Judgment (WCJ) of 2006 and the Green Tree Agreement (GTA) of 2006. The end of the five-year special regime program, as stipulated by the GTA, finally laid to rest the Bakassi conflict. Hitherto, following the end of hostilities between the Cameroonian and Nigerian military in the Bakassi Peninsula, the region was/is being marred by militant activities. The main thrust of this paper is to examine the role played by the Cameroonian and Nigerian military in maintaining peace in the Bakassi peninsula even after the conflict has been resolved. This research used the qualitative method with content and thematic analysis on some military activities in the Bakassi peninsula. Data was collected from secondary sources and observations from two field undertakings in Bamusso, Isangele, and Idabato subdivisions in the Bakassi region. After resolving the conflict, this paper cautions that Cameroonians and the Nigerian military have not only been engaged in security activities but have taken up new humanitarian and developmental activities. This research recommends for Cameroon and Nigerian governments divert heavy projects from the military to civilians, deploying more civilian personnel in the medical, judicial, and administrative fields in the Bakassi Peninsula. They should only limit the use of their military personnel in fighting piracy and militancy in the area. If such policies are implemented, both countries will be assured peace and tranquillity in the Bakassi Peninsula.

A novel Penta-jet VTOL aerial robot: Modeling, control, and simulation verification

This paper presents a novel unmanned aerial vehicle known as the “Penta-jet”, which uses mini turbojet engines as its power source. The Penta-jet offers superior power compared to small rotorcraft and demonstrates enhanced maneuverability during takeoff and landing in comparison to fixed-wing aircraft. The Penta-jet uses four small thrust turbojet engines to supply steering power and a large thrust turbojet engine to provide the main thrust. To analyze the motion characteristics of the Penta-jet, a mathematical model is proposed, focusing on the dynamic analysis of the aircraft’s power system and rotation vector system. To achieve fixed-point reach and trajectory-tracking tasks, a back-stepping control technology with integral terms is designed for the attitude subsystem (inner loop) and position subsystem (outer loop). Simulation results demonstrate the proposed control method has a shorter adjustment time and smaller overshoot compared with the traditional control method, especially in tracking spiral trajectories.

Morphotectonic assessment of the Gaula river basin, Kumaun lesser Himalaya, Uttarakhand

Morphotectonics is a discipline of geomorphology that explores how landforms are formed or modified by tectonic action. In the present study we uthe sed application of geospatial technology to evaluate the active deformation owing to Main Boundary Thrust (MBT) and Ramgarh Thrust (RT) in Outer part of Kumaun Lesser Himalaya. Active deformation inside river valleys is ascribed downcuttinging and incision of bedrock, offset of river channel, lateral migration of the river, and development of Knickpoints. Therefore, we used quantitative geo-mathematical analysis of The Gaula river basin using ASTER DEM along with survey of India Toposheet (1:50,000) supplemented by field observations. Four morphotectonic metrics, including the basin elongation ratio, the asymmetry factor, the channel sinuosity, and the hypsometric integral, were derived to examine the relative index of active tectonics (RIAT). We applied Stream Power Incision Model (SPIM) by analysing the steepness index (Ksn) using the stream power law. Additionally, a comprehensive evaluation of tributary streams of the Gaula watershed has been carried out to understand relative tectonic activity. Further we used Chi integral (χ) to measure transience dynamics and geometric disequilibrium of Gaula basin. We conclude that most sub-basins are tectonically enhanced, structurally organized and elongated in nature. The landform in the study area is largely controlled by presence of MBT, RT and subsidiary thrusts spread over in the vicinity. Based on our activity classes we concluded that approximately 31% of the area in Gaula river basin falls in very active whereas ∼34% is potentially active. Furthermore, we suggest that the results will be very useful for estimation of hazard potential zones in sub-Himalayan region of foothill zone of Kumaun Himalaya.

Militant or Non-State Armed Groups (NSAGs) During/After The Resolution of The Bakassi Conflict

The Bakassi peninsula conflict and its resolution had absorbed most of Cameroon and Nigeria's socio-political and economic oxygen and the international community in the 80s, 90s, and the first decade of the 21st century. Following military clashes between Cameroon and Nigeria over the peninsula, the conflict was finally resolved through the International Court of Justice (ICJ) verdict in 2002 and the Green Tree Agreement (GTA) 2006. The main thrust of this paper is to examine some militant or Non-State Armed Groups (NSAGs) that operated during and after the resolution of the Bakassi conflict. This paper also aims to examine the reasons why these NSAGs emerged briefly. This paper applied the qualitative research method and, from it, historical consolidation, content analyses and case studies. The study's results revealed seven prominent NSAGs that emerged during/after the resolution of the Bakassi conflict. The ICJ verdict of 2002 and the GTA of 2006 were one of prominent reasons why these NSAGs emerged. The study also found that the desire to control the area's natural resources, fight against Cameroon gendarme brutality, and the poor resettlement of the Bakassi returnees also served as springboards for the emergence of these NSAGs. Through its recommendations, this paper will help the Cameroon government redefine its policies toward ensuring and maintaining lasting peace in the Bakassi peninsula- understanding the reason for the emergence of the NSAGs, its trends, and how best to handle them.

Nature of the Himalayan Seismicity Belt in the Garhwal–Kumaun Segment and Its Tectonic Implications

Abstract High-quality data recorded by a dense network of 53 seismic stations in the Garhwal–Kumaun Himalaya between February 2017 and December 2021 is analyzed. A total of 813 local earthquakes are relocated using a newly developed regional 1D velocity model incorporating station corrections. In addition, focal mechanism solutions of M ≥ 3.8 events are estimated using waveform inversion. The relocated seismicity patterns along with the focal mechanism solutions are utilized to present a seismotectonic scenario of the region. Almost 95% of the relocated seismicity is found to be clustered along the Himalayan seismic belt (HSB), down to ∼24 km depth. Seismicity in this belt is interpreted to be caused due to interseismic stress loading associated with the ongoing India–Eurasia collision tectonics. A few scattered hypocenters in the deeper crust between 30 and 50 km depth attest the strength of the downgoing Indian plate. Focal mechanisms in the seismogenic upper crust reveal thrusting of the Indian plate beneath the Lesser Himalaya, with compression normal to the strike of the Main Central Thrust (MCT). The north-dipping thrust mechanisms can be associated with a near-horizontal Main Himalayan Thrust (MHT). In addition, more steeply dipping faults above it define the Lesser Himalayan duplex systems, similar to those in western and Nepal Himalaya. A prominent ∼50 km wide seismicity gap region observed within the HSB is probably due to (1) a locally varying locking width of the MHT; (2) an unruptured, ductile segment at the eastern end of the rupture zone of the great 1803 earthquake (Mw 7.8 ± 0.2); and (3) a slab tear in the MHT, similar to those in subduction zones.

Decoding the Late Pleistocene-Holocene Terrace Evolution along the Main Frontal Thrust Zone, Northeastern Himalayas, India: Insights from Tectonic Geomorphology, Sedimentology, and Optical Dating

Abstract Fluvial archives are the best preserved and provide valuable means of obtaining information pertaining to climate and tectonic deformation of an area. The present study is an attempt to reconstruct the landform evolution history in the northeastern Himalayan region of India. Based on field investigation, tectonogeomorphic mapping, and OSL dating, strath and various levels of cut-and-fill terraces were investigated along the mountain front. Optically stimulated luminescence ages of the terrace sequences suggest that the valley incision occurred in three phases, at ~23 ka, ~14 ka and ~9 – 3 ka and one phase of aggradation was also identified at ~ 7 ka. The strath terraces suggest two major episodes of tectonic uplift in the region around ~ 8 ka and ~ 6 ka. This yields an uplift rate of 0.4 and 0.9 mm/yr. The result from the study suggested that the rapid rejuvenation along the mountain front led to the formation of the strath terraces with enhanced incision of the fluvial terrace and influenced the sedimentary architecture of valley fill sequences.

Evidence of Strain Accumulation and Coupling Variation in the Himachal Region of NW Himalaya From Short Term Geodetic Measurements

AbstractHimachal region of Northwest Himalaya exhibits the widest structural re‐entrant in Kangra region and significant strain partitioning along the frontal and hinterland out‐of‐sequence faults. We report results of continuous GPS measurements from 10 new sites in the region and analyze them along with the previously published results to constrain the ongoing arc‐normal and arc‐parallel convergence rates at 16.5 ± 1.1 and 4–5 mm/yr respectively. Thus, the ongoing convergence is oblique by 15°–20°. The Main Himalayan Thrust (MHT) is strongly coupled up to ∼100 km from the Main Frontal Thrust but displays significant variation in coupling in the transition zone across the Kangra re‐entrant and the adjoining western salient. Joint analysis of the coupling variation, the geologically inferred MHT geometry variations and the local topographic anomaly pattern strongly suggest the possibility of a potentially active, strain accumulating segment of MBT along the southern margin of Dhauladhar ranges in Western Himachal region, which is also proposed to be influencing the long‐term topographic growth in the region. Although a general agreement is observed between the long‐term shortening rates along the active faults and the estimated geodetic convergence in this region, the ensuing discussion highlights their complex relationship in terms of temporal and spatial variability in the fault activity and elastic‐inelastic deformation. We use the fault orientation and the estimated convergence rate to geometrically constrain a mean dextral slip‐rate of 4.4–5.7 mm/yr along a recently discovered Khetpurali‐Taksal fault, which is proposed to partition the majority of ongoing arc‐parallel deformation along it.