The break-up of the Indian subcontinent from Gondwana: constrain by detrital zircon U-Pb dating of mid- Paleozoic-early Cenozoic strata in eastern Nepal

2020 ◽  
Author(s):  
Upendra Baral ◽  
Ding Lin
Keyword(s):  
Detrital Zircon ◽  
Indian Subcontinent ◽  
Continuous Process ◽  
Age Distribution ◽  
Eastern Coast ◽  
Peninsular India ◽  
Southwest Australia ◽  
Tethys Himalaya ◽  
Himalayan Orogenic Belt ◽  
Qiangtang Terrane

<p>The rifting and the amalgamation of earth landmass is a continuous process. The assembly of the Gondwana lasted from ~730 Ma to 500 Ma, and most of the mass is covered by glaciation at the southern hemisphere. Afterthought experienced multiple episodes of rifting and collision of small ribbon shape microcontinents. The extra-peninsular Gondwana sequence is discontinuous in the Himalayan orogenic belt while peninsular Gondwana sequence is broadly distributed in numerous intracratonic basins of peninsular India. The detrital zircon U-Pb ages from Permo-Carboniferous sequence peak at ~1164 with a subordinate peak at ~1305 Ma. This result emphasised that the sediments were mainly sourced from the Stenian magmatism in Albany-Fraser orogeny or the East Africa-Nibua and eastern coast of India, and southwest Australia. Also, the unit also contains sporadic volcanic unit (Baraha Volcanics). The Saptakoshi Formation, uncomfortably overlain the Khokha Diamictite, yield the peaks at ~522 Ma and 941 Ma with a younger peak at ~113 Ma with some older peaks at ~1811 and 1917 Ma. This younger detritus possibly sourced from the Rajhmahal basalt ~~115-120 Ma) while the remaining grains show a similar trend to the underlying Diamictite and overlying Tamrang Formation. Additionally, the Tamrang Formation have peaks at ~976 Ma, and 1716 Ma, identically identical to the Greater Himalayan sequence. The U-Pb age distribution of these three units coincide with the Tethys Himalaya further brings the possibility that either they share the same provenance or recycled from the Tethys Himalaya till Permian and onwards there was input from the Lhasa terrane, South Qiangtang terrane, and Indo China blocks.</p>

Neotypification of Terminalia paniculata (Combretaceae)

Phytotaxa ◽  
2017 ◽  
Vol 326 (1) ◽  
pp. 88
Author(s):  
TAPAS CHAKRABARTY ◽  
VENKATACHALAM SAMPATH KUMAR
Keyword(s):  
World War Ii ◽  
Indian Subcontinent ◽  
Original Material ◽  
World War ◽  
Botanical Survey ◽  
Peninsular India ◽  
The Family ◽  
Central National Herbarium ◽  
Terminalia Paniculata ◽  
Southern Regional

While preparing a revised treatment of the family Combretaceae for “Flora of India Project,” our attention was drawn on Terminalia paniculata Roth (1821: 383) which was described on the basis of a specimen collected by Benjamin Heyne from peninsular India. The species is well documented in Indian Floras (e.g. Wight & Arnott 1834, Beddome 1869, Brandis 1874, Clarke 1878, Cooke 1903, Talbot 1911, Gamble 1919 and Chandrabose 1983). Gangopadhyay & Chakrabarty (1997) in their revision of the family Combretaceae of Indian subcontinent mentioned that the type of this species is not extant. The type material of T. paniculata housed in the Berlin herbarium (B; herbaria acronyms follow Thiers 2017) was presumably destroyed during the World War II. In the Kew herbarium (K), there is a collection by Benjamin Heyne (K000786096: image!) identified and listed in Wallich’s Numerical List as T. triopteris B.Heyne ex Wallich (1831: no. 3980B). This material contains two twigs, one flowering and the other fruiting and this appears to be a specimen not seen by Roth (1821) since he clearly mentioned in the protologue: “Fructum non vidi.” Thus, as per the provisions of the Code (Mc Neill et al., 2012), as there is no other extant original material (Article 9.7) traceable, a neotype (Articles 9.11 and 9.13) is designated here for T. paniculata from Peninsular India, where Benjamin Heyne made botanical explorations (Burkill, 1965). The neotype specimen is housed in the Central National Herbarium, Botanical Survey of India, Howrah, India (CAL) and its duplicate in the Madras Herbarium, Botanical Survey of India, Southern Regional Centre, Coimbatore, India (MH).

scholarly journals Presence of continental and Bay of Bengal moisture in rainfall at Kolkata, revealed through simultaneous observation from land and sea during South-West monsoon of 2004

2016 ◽  
Author(s):  
Shaakir Shabir Dar ◽  
Prosenjit Ghosh
Keyword(s):  
Isotopic Composition ◽  
Bay Of Bengal ◽  
Indian Subcontinent ◽  
Isotopic Signature ◽  
Peninsular India ◽  
Gangetic Plain ◽  
Prevailing Wind Direction ◽  
South West Monsoon ◽  
Continental Source ◽  
Sw Monsoon

Abstract. The backward air mass trajectory analysis (HYSPLIT) during the summer monsoon suggests that the rain which precipitates at Kolkata is generated from a moisture parcel which originates from the Arabian Sea and moves inland over the dry Indian subcontinent or over the Bay of Bengal. We used monthly satellite and ground based measurements of the hydro-meteorological variables together with isotope data from Bangalore, Bay of Bengal and Kolkata and other locations to quantify the contribution of different moisture sources during the SW Monsoon. The vapor mass as it moves under the prevailing wind direction was subjected to isotopic modification due to addition of evaporated moisture from Bay of Bengal and rainout process. This was simulated using Craig and Gordon model and Rayleigh fractionation model respectively. The moisture generated during the process of evaporation from Bay of Bengal surface ocean gets advected towards the continent and precipitates as rainfall or snowfall over the Indo-Gangetic plain. We assumed based on our observation that the initial isotopic composition of vapor originating from the peninsular continental source is similar to our observation recorded at Bangalore station. It is found that the isotopic signature of Bangalore is completely lost albeit the significant contribution of the moisture from Bay of Bengal. To explain the isotopic composition of precipitation at Kolkata during the SW-Monsoon, it was necessary to invoke 75–80 % moisture contribution from the Bay of Bengal whereas the evaporated moisture parcel from the Peninsular India contribute 25 %–35 %.

Transition to Colonialism

2020 ◽  
pp. 17-65
Author(s):  
Tirthankar Roy
Keyword(s):  
Eighteenth Century ◽  
Private Property ◽  
Initial Conditions ◽  
Indian Subcontinent ◽  
Peninsular India ◽  
Highly Skilled ◽  
Fiscal Administration ◽  
The One ◽  
Territorial States

The eighteenth-century economy of the Indian subcontinent was an uneven one. On the one hand, there were present a rich indigenous commercial tradition; territorial states that respected private property in land and trade; a literate elite running the fiscal administration; and rich cities that were home to highly skilled artisans. But much of that wealth was confined to the riparian, deltaic, and seaboard regions. The greater part of peninsular India consisted of drylands, poor peasants, few roads, slow traffic, few towns, forests, waterless uplands, and uninhabited deserts. With such divergent initial conditions, the onset of globalization and the emergence of British power led to a variety of trajectories, as Chapter 2 shows.

Enigmatic provenance signature of sandstone from the Okwa Group, Botswana

2020 ◽  
Vol 123 (3) ◽  
pp. 331-342
Author(s):  
T. Andersen ◽  
M.A. Elburg ◽  
J. Lehmann
Keyword(s):  
South Africa ◽  
Detrital Zircon ◽  
Sedimentary Rock ◽  
Age Distribution ◽  
Sedimentary Rocks ◽  
Detrital Zircons ◽  
Significant Shift ◽  
Zircon Age ◽  
Three Samples ◽  
Isotope Distributions

Abstract Detrital zircon grains from three samples of sandstone from the Tswaane Formation of the Okwa Group of Botswana have been dated by U-Pb and analysed for Hf isotopes by multicollector LA-ICPMS. The detrital zircon age distribution pattern of the detrital zircons is dominated by a mid-Palaeoproterozoic age fraction (2 000 to 2 150 Ma) with minor late Archaean – early Palaeoproterozoic fractions. The 2 000 to 2 150 Ma zircon grains show a range of epsilon Hf from -12 to 0. The observed age and Hf isotope distributions overlap closely with those of sandstones of the Palaeoproterozoic Waterberg Group and Keis Supergroup of South Africa, but are very different from Neoproterozoic deposits in the region, and from the Takatswaane siltstone of the Okwa Group, all of which are dominated by detrital zircon grains younger than 1 950 Ma. The detrital zircon data indicate that the sources of Tswaane Formation sandstones were either Palaeoproterozoic rocks in the basement of the Kaapvaal Craton, or recycled Palaeoproterozoic sedimentary rocks similar to the Waterberg, Elim or Olifantshoek groups of South Africa. This implies a significant shift in provenance regime between the deposition of the Takatswaane and Tswaane formations. However, the detrital zircon data are also compatible with a completely different scenario in which the Tswaane Formation consists of Palaeoproterozoic sedimentary rock in tectonic rather than depositional contact with the other units of the Okwa Group.

Evaluation of emission strength efficacy in simulating black carbon burden with CHIMERE: estimating wintertime radiative effect over Indo-Gangetic Plain

2020 ◽  
Author(s):  
Sanhita Ghosh ◽  
Shubha Verma ◽  
Jayanarayanan Kuttippurath
Keyword(s):  
Black Carbon ◽  
Transport Model ◽  
Indian Subcontinent ◽  
Chemical Transport ◽  
Climate Impacts ◽  
Eastern Coast ◽  
Spatial And Temporal Patterns ◽  
Gangetic Plain ◽  
Bc Aerosols ◽  
Indo Gangetic Plain

<p>Black carbon (BC) aerosols over the Indian subcontinent have been represented inadequately so-far in chemical transport models restricting the accurate assessment of BC-induced climate impacts. The divergence between simulated and measured BC concentration has specifically been reported to be large over the Indo-Gangetic Plain (IGP) during winter when a large BC burden is observed. In this study, we evaluate the BC transport simulations over the IGP in a high resolution (0.1º × 0.1º ) chemical transport model, CHIMERE. We examine the model efficiency to simulate the observed BC distribution executing five sets of simulation experiments: <em>Constrained </em>and<em> bottomup</em> (<em>Smog, Pku, Edgar, Cmip</em>) implementing respectively, the recently estimated India-based constrained BC emission and the latest bottom-up BC emissions (India-based: Smog-India, and global: Coupled Model Intercomparison Project phase 6 (CMIP6), Emission Database for Global Atmospheric Research-V4 (EDGAR-V4) and Peking University BC Inventory (PKU)). The mean BC emission flux over most of the IGP from the five emission datasets is considerably high (450–1000 kg km<sup>-2</sup> y<sup>-1</sup>) with a relatively low divergence obtained for the eastern and upper-mideastern IGP. Evaluation of BC transport simulations shows that the spatial and temporal gradient in the simulated BC concentration from the <em>Constrained </em>was equivalent to that from the <em>bottomup</em> and also to that from observations. This indicates that the spatial and temporal patterns of BC concentration are consistently simulated by the model processes. However, the efficacy to simulate BC distribution is commendable for the estimates from <em>Constrained</em> for which the lowest normalised mean bias (NMB, < 20%) is obtained in comparison to that from the <em>bottomup</em> (37–52%). 75–100% of the observed all-day (daytime) mean BC concentration is simulated most of the times (>80% of the number of stations data) for <em>Constrained</em>, whereas, this being less frequent (<50%) for the <em>Pku, Smog, Edgar</em> and poor for <em>Cmip</em>. The BC-AOD (0.04–0.08) estimated from the <em>Constrained</em> is 20–50% higher than the <em>Pku</em> and <em>Smog</em>. Three main hotspot locations comprising of a large value of BC load are identified over the eastern, mideastern, and northern IGP. Assessment of the effect of BC burden on the wintertime radiative perturbation over the IGP shows that the presence of BC aerosols in the atmosphere enhances atmospheric heating by 2–3 times more compared to that considering atmosphere without BC. Also, a net warming at the top of the atmosphere (TOA) by 10–17 W m<sup>-</sup><sup>2</sup> is noticed from the <em>Constrained</em>, with the largest value estimated in and around megacities (Kolkata and Delhi) that extends to the eastern coast. This value is higher by 10–20% than that from <em>Cmip</em> over the IGP and by 2–10% than that from <em>Smog</em> over Delhi and eastern part of the IGP.</p>

scholarly journals Single Genetic Stock Revealed by Microsatellite Markers Among Wild Populations of Cirrhinus mrigala from Peninsular India

2021 ◽  
Vol 21 (09) ◽  
pp. 425-433
Author(s):  
Sofia P. Das ◽  
Subrat K. Swain ◽  
Lakshman Sahoo ◽  
Joy Krushna Jena ◽  
Paramananda Das
Keyword(s):  
Genetic Variation ◽  
Fishery Management ◽  
Indian Subcontinent ◽  
Genetic Stock ◽  
Peninsular India ◽  
Essential Information ◽  
Cirrhinus Mrigala ◽  
Exact Test ◽  
Indian Major Carps ◽  
Commercially Important

Cirrhinus mrigala (mrigal) is one of the Indian major carps widely cultured in the whole Indian subcontinent. Population genetic structure of this species from Peninsular Rivers of India is lacking. Among DNA markers, microsatellites are excellent tools to evaluate genetic variation of populations. In this study, genetic variation of six peninsular riverine mrigal populations was evaluated using seventeen microsatellite loci. In analyzing 288 samples, the number of alleles ranged from 4 to 27; observed heterozygosity from 0.595 to 1.00, expected heterozygosity from 0.586 to 0.959 and inbreeding coefficient (FIS) ranged from -0.034 to 0.02. Exact test for Hardy Weinberg disequilibrium revealed that one locus was not in equilibrium across the rivers except one. The AMOVA analysis revealed the main source of genetic variation to be within the population (94.54%) than among the populations (5.46%). The Nei’s genetic distance and structure analysis depict river Narmada and Mahi populations are different from the four east coast rivers. The overall Fst (0.05462) data showed moderate differentiation among the six populations. The results of this study provide essential information to resource recovery and help in delineating populations for fishery management. Besides, the data will provide a valuable baseline for further investigations on the geographic distribution of this commercially important fish species.

scholarly journals Supplemental Material: Detrital zircon geochronology and Hf isotope geochemistry of Mesozoic sedimentary basins in south-central Alaska: Insights into regional sediment transport, basin development, and tectonics along the NW Cordilleran margin

2020 ◽  
Author(s):  
C.R. Fasulo ◽  
et al.
Keyword(s):  
Detrital Zircon ◽  
Isotope Geochemistry ◽  
Age Distribution ◽  
Sedimentary Basins ◽  
Alaska Range ◽  
Zircon Age ◽  
Detrital Zircon Geochronology ◽  
South Central ◽  
Cordilleran Margin ◽  
Detrital Zircon Ages

Supplemental Figure S1. Normalized distribution plot of detrital zircon ages from the Kahiltna assemblage of the central Alaska Range (Hampton et al., 2010), the Wellesly basin (this study), and the Kahiltna assemblage of the northwestern Talkeetna Mountains (Hampton et al., 2010). Note that the detrital zircon age distribution of ages older than 500 Ma has 10× vertical exaggeration.

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