India Asia Research Articles

Geochronological enigma of the HP–UHP rocks in the Himalayan orogen

Abstract The subduction of Indian plate lithosphere during its collision with Asian plate in the Eocene resulted in a regional metamorphic belt along the strike of the Himalayan orogen. High-/ultrahigh-pressure (HP/UHP) metamorphic rocks (eclogites and host gneisses) confirm the metamorphic event in western Himalaya (Kaghan c. 46 Ma and Tso Morari at c. 47 Ma) at mantle depths (>90 km: coesite-stable). In contrast, HP/UHP rocks have not been reported from central and eastern Himalaya and only highly retrogressed eclogites and granulites ( c. 25 to 13 Ma) occur. The presence of UHP rocks in western Himalaya and highly retrogressed eclogites and granulites in central and eastern Himalaya was regarded as evidence for a diachronous India–Asia collision. Despite the along-strike regional homogeneity in major lithotectonic units of the Himalayan orogen, metamorphic diachroneity is enigmatic. It is unlikely to have a subduction-related prolonged progressive metamorphic event. In contrast, the age difference and preservation of UHP phases in the west and their transformation into granulites in central and eastern Himalaya could be associated with their prolonged residence times at crustal levels in the central and eastern Himalaya whereas the rocks exhumed rapidly in the west. The higher thermal events relating to melting of the subducting Indian lithosphere in central and eastern Himalaya evidenced from ultra-potasic volcanics in southern Tibet probably decompressed the early metabasites into granulitized eclogites, even resetting their geological clock, which is why eclogites and granulites in the east show younger ages compared with their UHP counterparts in the west.

Mesozoic-Cenozoic tectonic evolution and metallogeny in Myanmar: Evidence from zircon/cassiterite U–Pb and molybdenite Re–Os geochronology

It is well known that there are many Sn–W–Mo and Cu–Au metal resources in Myanmar. However, the absence of precise mineralization ages for these deposits significantly hinders to understand the close genetic relationship among metallogeny, ore-bearing intrusions, and tectonic evolution. In this study, two groups of consistent molybdenite Re–Os and zircon U–Pb ages indicate that the Dapingba Mo–W deposit in northern Myanmar (Tengchong terrane) formed at Early Cretaceous (∼119 Ma and ∼114 Ma). The Dapingba ore-bearing granitic magmas were mainly derived from melting of ancient Tengchong crust on the basis of zircon Hf isotopic compositions (εHf(t) = −9.3 to 2.5). Moreover, the first reported cassiterite U–Pb ages of ∼60 Ma for the Bawapin and Kalonta Sn–W deposits in southern Myanmar (western Sibumasu terrane) suggest that the two deposits formed at Paleocene. Whereas the precise molybdenite Re–Os age for the Shangalon porphyry Cu–Au deposit in the West Burma terrane indicates that this deposit formed at Eocene (∼39 Ma). Importantly, combined with previous studies on tectonic evolution and magmatic petrogenesis in Myanmar and southwest China, a comprehensive Mesozoic-Cenozoic tectono-magmatic and metallogenic model are proposed. Two periods of Early Cretaceous (∼120–114 Ma) and Late Cretaceous (∼75–70 Ma) crust-derived felsic melts and related Mo–Sn–W deposits from the Tengchong and western Sibumasu terranes likely formed in a continental arc during subduction of the Meso- and Neo-Tethys oceanic lithosphere, respectively. Subsequently, Paleocene-Eocene (∼60–50 Ma) Sn–W deposits and coeval ore-bearing granites in the western Sibumasu terrane possibly formed during roll-back of the Neo-Tethys oceanic slab. After ∼50 Ma India–Asia collision, Eocene (∼41–39 Ma) porphyry Cu–Au (West Burma terrane) and Sn–W deposits (western Sibumasu terrane) likely formed during the Neo-Tethys oceanic slab tear and break-off in a collisional setting. Whereas Miocene (∼19–14 Ma) high sulfidation epithermal Cu deposit in the West Burma terrane possibly formed in an arc setting during oblique subduction of the Indian oceanic lithosphere.

High-Tin Forged Oriental Bronzes on the Territory of Khazaria

Two bronze artefacts, a mirror fragment and a dish, were found in the territory of Khazaria, at the site of Right-bank Tsimliansk fortified settlement in a household pit, and near Bolshaia Orlovka settlement in a destroyed barrow mound. Right-bank Tsimliansk fortified settlement dates to the second half of the 9th century, while the burial from Bolshaia Orlovka falls within the 8th century. Chemical and technological investigation of the artefacts showed that both were made of bronze with 20-21% tin using hot forging. Similar technology for producing vessels, mirrors and other items emerged in the 6th-4th centuries В.С.E. in Eastern [“Oriental”] territories such as Central Asia, India, Iran, and south-eastern Asia. The methodology exists in some countries today. Rather than concluding that the finds represent evidence of regular trade contacts between Khazaria and the East, the authors consider that the artefacts are unique unrepresentative finds.

Sediment control on subduction plate speeds

Tectonic plate velocities predominantly result from a balance between the potential energy change of the subducting slab and viscous dissipation in the mantle, bending lithosphere, and slab–upper plate interface. A range of observations suggest that slabs may be weak, implying a more prominent role for plate interface dissipation than previously thought. The shallow thrust interface is commonly assumed to be weak due to an abundance of fluids and near-lithostatic pore fluid pressures, but little attention has been paid to the influence of the deeper, viscous interface. Here we show that the deep interface viscosity in subduction zones is strongly affected by the relative proportions of sedimentary to mafic rocks that are subducted to depth. Where sediments on the down-going plate are sparse, the deep interface is dominated by mafic lithologies that metamorphose to eclogites, which exhibit viscosities 1–2 orders of magnitude higher than the asthenospheric mantle, and reduce subduction plate speeds. In contrast, where sediments are abundant and subducted to depth, the deep interface viscosity is 1–2 orders of magnitude lower than the asthenospheric mantle, thus allowing significantly faster plate velocities. This correlation between subduction plate speed and deep sediment subduction may help explain dramatic accelerations (or decelerations) in convergence rates, such as the acceleration documented for India–Asia convergence during the mid-Cenozoic.

Mantle kinematics driving collisional subduction: Insights from analogue modeling

Since several decades, the processes allowing for the subduction of the continental lithosphere less dense than the mantle in a collision context have been widely explored, but models that are based upon the premise that slab pull is the prominent driver of plate tectonics fail. The India–Asia collision, where several episodes of continental subduction have been documented, constitute a case study for alternative views. One of these episodes occurred in the early collision time within the Asian plate where continental lithosphere not attached to any oceanic lithosphere subducted southward in front of the Indian lithosphere during its northward subduction that followed the oceanic subduction of the Tethys ocean. This process, known as collisional subduction, has a counter-intuitive behavior since the subduction is not driven by slab pull. It has been speculated that the mantle circulation can play an important role in triggering collisional subduction but a detailed, qualitative analysis of it is not available, yet. In this work we explore the southward subduction dynamics of the Asian lithosphere below Tibet by means of analogue experiments with the aim to highlight how the mantle circulation induces or responds to collisional subduction. We found that during the northward oceanic subduction (analogue of Tethys subduction) attached to the indenter (Indian analogue), the main component of slab motion is driven vertically by its negative buoyancy, while the trench rolls back. In the mantle the convective pattern consists in a pair of wide convective cells on both sides of the slab. But when the indenter starts to bend and plunge in the mantle, trench motion reverses. Its advance transmits the far field forces to two upper plates (Asian analogues). The more viscous frontal plate thickens, and the less viscous hinterland plate, which is attached to the back wall of the box, subducts. During this transition, a pair of sub-lithospheric convective cells is observed on both sides of the Asian analogue slab, driven by the shortening of the frontal plate. It favors the initiation of the backwall plate subduction. Such subduction is maintained during the entire collision by a wide cell with a mostly horizontal mantle flow below Tibet, passively advecting the Asian analogue slab. Experimental results suggest that once the tectonic far-field force related to the forward horizontal motion becomes dominant upon the buoyancy forces, trench advancing and the transmission of the tectonic force to the upper and backwall plates are promoted. This peculiar condition triggers the subduction of the backwall plate, despite it is light and buoyant.

Timing of subduction initiation, arc formation, ophiolite obduction and India–Asia collision in the Himalaya

Abstract Reconstruction of the Western Himalaya requires three subduction systems operating beneath the Spong arc, Dras–Kohistan arc and the Asian continent during the Late Cretaceous–Paleocene. The timing of the closure of the Neo-Tethys Ocean along the Indus Suture Zone (ISZ) in Ladakh and south Tibet has been proposed to be as old as c. 65 Ma and as young as c. 37 Ma. The definition of the India–Asia collision can span >15 myr from the first touching of Indian continental crust with Asian crust to the final marine sedimentation between the two plates. There is good geological evidence for a Late Cretaceous–Early Paleocene phase of folding, thrusting and crustal thickening of Indian Plate shelf carbonates associated with obduction of ophiolites. There is no geological evidence of any oceanic ‘Greater Indian Basin’ separating the northern Tethyan and Greater Himalaya from India. There is clear evidence to support final ending of marine sedimentation along the ISZ at 50 Ma (planktonic foraminifera zone P7–P8). There is no evidence for diachroneity of collision along the Pakistan–Ladakh–South Tibet Himalaya. The timing of ultrahigh-pressure metamorphism cannot be used to constrain India–Asia collision, and the timing of high-grade kyanite- and sillimanite-grade metamorphism along the Greater Himalaya can only give a minimum age of collision.

Structural and metamorphic evolution of the Karakoram and Pamir following India–Kohistan–Asia collision

Abstract Following the c. 50 Ma India–Kohistan arc–Asia collision, crustal thickening uplifted the Himalaya (Indian Plate), and the Karakoram, Pamir and Tibetan Plateau (Asian Plate). Whereas surface geology of Tibet shows limited Cenozoic metamorphism and deformation, and only localized crustal melting, the Karakoram–Pamir show regional sillimanite- and kyanite-grade metamorphism, and crustal melting resulting in major granitic intrusions (Baltoro granites). U/Th–Pb dating shows that metamorphism along the Hunza Karakoram peaked at c. 83–62 and 44 Ma with intrusion of the Hunza dykes at 52–50 Ma and 35 ± 1.0 Ma, and along the Baltoro Karakoram peaked at c. 28–22 Ma, but continued until 5.4–3.5 Ma (Dassu dome). Widespread crustal melting along the Baltoro Batholith spanned 26.4–13 Ma. A series of thrust sheets and gneiss domes (metamorphic core complexes) record crustal thickening and regional metamorphism in the central and south Pamir from 37 to 20 Ma. At 20 Ma, break-off of the Indian slab caused large-scale exhumation of amphibolite-facies crust from depths of 30–55 km, and caused crustal thickening to jump to the fold-and-thrust belt at the northern edge of the Pamir. Crustal thickening, high-grade metamorphism and melting are certainly continuing at depth today in the India–Asia collision zone.

Growth of mountain belts in central Asia triggers a new collision zone in central India

Several unusual strong earthquakes occurred in central India along the Narmada-Son Lineament (NSL) zone, far from active plate boundaries. To understand the role of collisional processes in the origin of this seismicity, we develop a numerical thermomechanical model of shortening between the Indian Plate and Asia. We show that at the final stage of collision, the shortening rate of the high mountain areas slows. The continuing convergence of India and Asia triggers the initiation of a new collision zone in continental part of India. Various geological and geophysical observations indicate that the NSL is a weakest zone with northward thrusting of the thinner central Indian lithosphere underneath the thicker northern part of the Indian Plate. We hypothesize that the NSL was reactivated during the final stage of the India Asia convergence and it will possibly form a new mountain belt within the Indian continent.

‘A walk for our race’: colonial modernity, Indigenous mobility and the origins of the Young Māori Party

This article argues that concepts of colonial modernity, originally developed for India and East Asia, and attention to micro-mobilities can provide new understandings of the emergence of Indigenous modernity in settler societies. Using previously unexplored sources, it examines a (seemingly small and local) walking tour by three Māori schoolboys in 1892 to ‘save their race from extinction’. An exemplary expression of Māori modernity, this walk is frequently cited as marking the earliest origins of the Young Māori Party, one of the most significant Māori organisations of the early twentieth century. Prior work on this group has been almost entirely confined within New Zealand historiography where it has been the subject of significant critique as a force for assimilation. Connecting this ‘walking tour’ with colonial and Indigenous histories elsewhere provides new ways of conceiving its significance, both locally and in its wider implications, that avoid such tropes. It demonstrates the possibilities of keeping both the local and the global in view, and indeed how this can amplify the importance of local histories.

EUROPEAN GENOCODES OF NATIONAL CULTURES. IN VARIETATE CONCORDIA

This paper has summarized the foundations of the author’s interdisciplinary concept of national cultures genocodes (NCG), which represents synthesis of of the Hegelian doctrine about national spirits (Volksgeist), the Jung’s theory of the collective unconscious, system of hexagrams of the Ancient Chinese Book of Changes and Girt Hofstede’s measurements of national cultures. There are generic genes (archetypes) and species ones in the national genocodes. Generic genes are the cornerstone of 6 cultural kingdoms, and specific genes — separate national cultures. All countries measured by Hofstede are divided into 6 cultural kingdoms. Kingdoms of Qian, Creative (USA, Canada, Australia, Poland and Scandinavia), Lee, Radiance (Western Europe) and Gen, Keeping Still (Japan) have an individualistic genocode. Kingdoms Zhen, Arousing (Russia, the Balkans, Greece, Turkey, Central Asia), Dui, Joyous (Africa, Latin America, Middle East) and Kun, Receptive (China, India and Southeast Asia) have a collectivist genocode. The basis of European civilization is the generic genes of the kingdoms of Lee, Qian and Zhen. The interaction between the generic and species genes of these kingdoms, their complementarity or conflict lies at the heart of alliances or wars between states. It has been shown that the greatest conflicts are observed between countries with individualistic and collectivist cultures, therefore the Balkan countries, Greece, Turkey and Russia throughout history were in a varying degree unfavorable relations with the Western European countries. But studying NCG will allow to minimize tension between countries, to understand a role and the place of each country in the World and in particular the European Cultural Space, to lay a way to the long-term union of peoples and states.

MODELING HUMAN BRUCELLOSIS USING ATMOSPHERIC VARIABLES IN FARS PROVINCE DURING THE YEARS 2009 TO 2011 USING GIS

Introduction: Brucellosis (brucellosis) is a common bacterial infectious disease between humans and animals. There is a widespread global dispersal disorder. Illness occurs throughout the world, especially in the Mediterranean countries (Southern Europe, North and East Africa), the Middle East, India and Central Asia. In this study we modeled the effects of atmospheric variables on human brucellosis disease. Methods: This study is a correlational (ecological) study. In this study, all of the cities of Fars province as sampling units and atmospheric variables including malt fever - temperature, humidity, rainfall, evaporation, sunshine, rain, frost and wind speed were estimated based on city division. It turned out Data were collected by city and city, and data analysis was done using descriptive statistics and regression analysis using GIS. Results: The incidence of brucellosis in the years 2009, 2010 and 2011 was 11.47 and 14.03 and 20.05 per 100,000 populations, respectively. The two variables of mean temperature and evaporation were two variables that influenced the model, which were able to model 21% of the changes in brucellosis. Conclusion: The present study showed that the incidence of brucellosis is significantly affected by atmospheric factors such as temperature and evaporation

Constraining the age of high-pressure metamorphism of paragneisses from the Eastern Himalayan Syntaxis using zircon petrochronology and phase equilibria

Abstract The metamorphic evolution of the Eastern Himalayan Syntaxis (EHS) is of primary importance in understanding the tectonic framework of the India–Asia collision. However, the age of formation and exhumation of the high-pressure granulites from the EHS remains controversial. In this paper, we report the age of metamorphism of high-pressure (HP) granulite-facies paragneisses from the Namche Barwa Complex (NBC). These paragneisses consist of variable proportions of garnet, biotite, plagioclase, K-feldspar, quartz, rutile and ilmenite. Using phase equilibrium modelling of garnet growth combined with partitioning of rare earth elements (REEs) between zircon and garnet, we link multistage zircon growth to garnet growth to date the prograde stage to the interval 32.6–25.2 Ma, the pressure peak to c. 25–24 Ma and the retrograde stage to the interval 23.5–13.1 Ma. Taking into account published ages from the literature, for the NBC we propose that the prograde to peak metamorphism persisted until c. 25–24 Ma. This was followed by exhumation and melt crystallization during the interval 24–8 Ma, and cooling through the amphibolite facies after c. 8 Ma.

A Concept of the Russian Agro-Food Sector

The instability of the Russian economy (because of its dependence on the international hydrocarbons market and the extension of the 2014 sanctions) raises the need for a comprehensive concept of the Russian agro-food sector. This concept should include a set of long-term priorities and objectives for developing the agro-food sector. This article examines the macroeconomic problems facing the Russian agro-food sector and considers several long-term objectives for fostering economic growth, including the promotion of small and medium businesses and the integration into new international markets. The Eurasian Economic Union forms a transportation corridor, directly linking western Europe with China, India, and central and Southeast Asia. Particular attention is given to the development of export infrastructure (port facilities, trans-shipment bases, etc.), the creation of common standards in the transportation sector, and the convergence of transportation and transit tariffs. It is argued that small and medium businesses are highly adaptable, with the capacity to quickly adopt new technologies, to respond to new investment and changing consumer demand, and to integrate into value chains connected to new markets.

<b>Inventory of teloganodid mayflies (Ephemeroptera: Teloganodidae) from southern India with records of endemic taxa</b>

The present study deals with diagnostic characters, diversity, distribution and status of seven species belonging to four genera of Teloganodidae from southern India. Six of them are endemic to the Western Ghats as is the genus Indoganodes Selvakumar, Sivaramakrishnan & Jacobus, 2014 and one is endemic to the Eastern Ghats. Due to this high percentage of endemism, conservation of habitats and microhabitats harbouring this ancient gondwanan lineage gains priority. A larval key to the known genera and species of Teloganodidae of southern India is also provided. The present pattern of distribution of the family Teloganodidae is confined to southern Africa, Madagascar, southern India and Southeast Asia.

Gastrodia elatoides (Orchidaceae: Epidendroideae: Gastrodieae), a new holomycoheterotrophic orchid from Madagascar

Gastrodia Brown (1810: 330; Gastrodieae, Epidendroideae) is a genus of holomycoheterotrophic orchids distributed from India and eastern Asia through Malaysia to Australia, as well as in tropical Afro-Madagascar (Pearce & Cribb 2002, Kores & Molvray 2005, Chen et al. 2009, Cribb et al. 2010). In this genus, 85 species have been accepted based on the combined information from Govaerts et al. (2018) and recently published new records of Gastrodia species (Jin & Kyaw 2017, Metusala & Supriatna 2017, Suetsugu 2017, Aung & Jin 2018). Consequently, it is now the largest holomycoheterotrophic genus among vascular plants (Hsu et al. 2016, Suetsugu 2017). Gastrodia is characterised by a fleshy tuber or coralloid rhizome, fusion of sepals and petals, a spurless lip and two sectile pollinia (Pearce & Cribb 2002, Kores & Molvray 2005, Chen et al. 2009). One species, G. elata Blume (1856: 174), is a highly valued plant in traditional Chinese medicine (TCM) for the treatment of convulsive disorders such as epilepsy (Cribb et al. 2010, Chen et al. 2009).

Late Cretaceous–Cenozoic thermochronology in the southern Songliao Basin, NE China: New insights from apatite and zircon fission track analysis

The Late Cretaceous–Cenozoic thermochronology in the southern Songliao Basin was determined using apatite and zircon fission track analysis data. It is crucial to deciphering the evolution of the Songliao Basin and changes in the movement direction of the Pacific Plate. We present eight new apatite and eight corresponding zircon fission track data from borehole samples across the Baixingtu uplift. The apatite fission track (AFT) thermochronological modeling reveals that the basin underwent two distinct compression- and extension-related uplift stages of rapid cooling during the Late Cretaceous–Cenozoic: stage I during the Late Cretaceous–Early Paleogene (∼70–52 Ma), stage II in the Late Paleogene–Early Neogene (∼38–10 Ma). The AFT data vary from 76.0 ± 5.0 to 25.3 ± 1.9 Ma and the zircon binomial peak fitting ages ranged from 79 to 61 Ma, all younger than the stratigraphic ages (∼92–88 Ma) of their host rocks. One sample had similar fission track ages (apatite 76.0 ± 5.0 Ma and zircon 79.0 ± 3.0 Ma) within reasonable error, representing a magmatic event. The data were divided into four groups. (i) 79–76 Ma: magmatic cooling event, (ii) 69–61 Ma: uplift of the whole region and exhumation and erosion, (iii) 37–34 Ma and (iv) ∼25 Ma: various uplift events related to tectonic inversion, causing partial uplift, exhumation and erosion in the basin. This created favorable conditions for formation and storage of mineral resources, especially sandstone uranium ore deposits. Our results combined with previous research suggest that the variation in uplift and exhumation began in the basin’s SE part and propagated to the NW ∼5–8 Ma later. The tectonic inversion in the southern Songliao Basin at least began ∼37–34 Ma. This corresponds with the time of the Paleo-Pacific Plate shifting to NWW motion and the India–Asia collision. These regional-scale uplift, exhumation and inversion events were probably responses to the subduction and turning of the Paleo-Pacific Plate from the southeast and the collision of the Indian subcontinent from the southwest. It is important to study the tectonic inversion in the whole east of China since the Late Cretaceous and the change of the direction of the Pacific plate movement.

Role of pre-existing structures in controlling the Cenozoic tectonic evolution of the eastern Tibetan plateau: New insights from analogue experiments

Pre-existing weakness due to repeated tectonic, metamorphic, and magmatic events is a fundamental feature of the continental lithosphere on Earth. Because of this, continental deformation results from a combined effect of boundary conditions imposed by plate tectonic processes and heterogeneous and anisotropic mechanical strength inherited from protracted continental evolution. In this study, we assess how this interaction may have controlled the Cenozoic evolution of the eastern Tibetan plateau during the India–Asia collision. Specifically, we use analogue models to evaluate how the pre-Cenozoic structures may have controlled the location, orientation, and kinematics of the northwest-striking Xianshuihe and northeast-striking Longmen Shan fault zones, the two most dominant Cenozoic structures in eastern Tibet. Our best model indicates that the correct location, trend, and kinematics of the two fault systems can only be generated and maintained if the following conditions are met: (1) the northern part of the Songpan–Ganzi terrane in eastern Tibet has a strong basement whereas its southern part has a weak basement, (2) the northern strong basement consists of two pieces bounded by a crustal-scale weak zone that is expressed by the Triassic development of a northwest-trending antiform exposing middle and lower crustal rocks, and (3) the region was under persistent northeast–southwest compression since ∼35 Ma. Our model makes correct prediction on the sequence of deformation in eastern Tibet; the Longmen Shan right-slip transpressional zone was initiated first as an instantaneous response to the northeast–southwest compression, which is followed by the formation of the Xianshuihe fault about a half way after the exertion of northeast–southwest shortening in the model. The success of our model highlights the importance of pre-existing weakness, a key factor that has been largely neglected in the current geodynamic models of continental deformation.

118–115 Ma magmatism in the Tethyan Himalaya igneous province: Constraints on Early Cretaceous rifting of the northern margin of Greater India

Understanding the dynamics of Large Igneous Provinces (LIPs) is critical to deciphering processes associated with rupturing continental lithosphere. Microcontinental calving, the rifting of microcontinents from mature continental rifted margins, is particularly poorly understood. Here we present new insights into these processes from geochronological and geochemical analyses of igneous rocks from the Tethyan Himalaya. Early Cretaceous mafic dikes are widely exposed in the eastern and western Tethyan Himalaya, but no such rocks have been reported from the central Tethyan Himalaya. Here we present an analysis of petrological, geochronological, geochemical, and Sr–Nd–Hf–Os isotopic data for bimodal magmatic rocks from the center-east Tethyan Himalaya. Zircon U–Pb dating yields six weighted-mean concordant 206Pb/238U ages of 118±1.2 to 115±1.3 Ma. Mafic rocks display MORB-like compositions with flat to depleted LREE trends, and positive εNd(t) (+2.76 to +5.39) and εHf(t) (+8.0 to +11.9) values. The negative Nb anomalies and relatively high 187Os/188Os ratios (0.15–0.19) of these rocks are related to variable degrees (up to 10%) of crustal contamination. Geochemical characteristics indicate that mafic rocks were generated by variable degrees (2–20%) of partial melting of spinel lherzolites in shallow depleted mantle. Felsic rocks are enriched in Th and LREE, with negative Nb anomalies and decoupling of Nd (εNd(t) = −13.39 to −12.78) and Hf (εHf(t) = −4.8 to −2.0), suggesting that they were derived mainly from garnet-bearing lower continental crust. The geochemical characteristics of the bimodal magmatic associations are comparable to those of associations that form in a continental rift setting. Results indicate that Early Cretaceous magmatism occurred across the whole Tethyan Himalaya, named here as the “Tethyan Himalaya igneous province”. Separation of the Tethyan Himalaya from the Indian craton may have occurred during ongoing Early Cretaceous extension related to the Kerguelen mantle plume during the nascent stages of a global plate-reorganization event. If this is the case, our findings provide clues to the nature of the Tethyan Himalaya, challenging traditional view of the India–Asia single-stage collision model.

Detrital zircon U–Pb ages, Hf isotopic constraints, and trace element analysis of Upper Cretaceous–Neogene sedimentary units in the Western Nepal Himalaya: Implications for provenance changes and India–Asia collision

The present study integrates detrital zircon U–Pb–Hf isotopic analysis from 13 sandstone samples from an Upper Cretaceous–Miocene sedimentary sequence in Nepal Himalaya to determine their provenance. These sequences constrain a shifting of provenance from south to north. The U–Pb ages from Upper Cretaceous–Palaeocene strata (Amile Formation) mainly cluster between ~1,860 and 1,400 Ma with a peak at ~1,630 Ma and an absence of grains younger than the Palaeoproterozoic (1,400 Ma) age. The detritus yielded positive detrital zircon ƐHf (t) values (as high as +10). However, the detrital zircon U–Pb ages from Eocene–Miocene sequence cluster at ~500–650, ~700–900, ~1,600–1,850, and ~2,500 Ma, and in addition, they have both positive and negative ƐHf (t) values (+11 to −25). This finding further elucidates that the detritus in the Amile Formation was entirely sourced from India, which changed following the time of the Bhainskati Formation deposition, to a mixture of both Asian and Indian affinities (the Himalayan region). This change in source region marks the possible time of the India–Asia collision during this transition phase, that is, Late Palaeocene–Earliest Eocene.

The complete chloroplast genome of tropical and sub-tropical fruit tree Lucuma nervosa (Sapotaceae)

The Lucuma nervosa, native to Western Ghats of India, Malaysia and south-eastern Asia, is a tree member of the mulberry family (Sapotaceae). Chloroplast genome sequences play an significant role in the development of molecular markers in plant phylogenetic and population genetic studies. In this study, we report the complete chloroplast genome sequence of L. nervosa for the first time. The chloroplast genome is 157,920 bp long and includes 113 genes. Its LSC, SSC, and IR regions are 88,123, 18,861, and 25,468 bp long, respectively. Phylogenetic tree analysis exhibited that L. nervosa was clustered with other Sapotaceae species with high bootstrap values.