New constraints on the tectono‐magmatic evolution of the Tidding‐Mayodia ophiolites, eastern Himalaya, northeast India

2021 ◽  
Author(s):  
Athokpam Krishnakanta Singh ◽  
Amrita Dutt ◽  
Bibhuranjan Nayak ◽  
Raj Kumar Bikramaditya ◽  
Govind Oinam ◽  
...  
Keyword(s):  
Northeast India ◽  
Eastern Himalaya ◽  
Magmatic Evolution

Seismicity, gravity, and tectonics of northeast India and northern Burma

1976 ◽  
Vol 66 (5) ◽  
pp. 1683-1694
Author(s):  
R. K. Verma ◽  
Manoj Mukhopadhyay ◽  
M. S. Ahluwalia
Keyword(s):  
Large Scale ◽  
Bouguer Anomaly ◽  
Northeast India ◽  
Eastern Himalaya ◽  
Basic Material ◽  
Bengal Basin ◽  
Seismic Zone ◽  
Shillong Plateau ◽  
Eurasian Plate ◽  
High Seismicity

abstract Practically the whole of northeastern India and northern Burma is characterized as an anomalous gravity field as well as an area of high seismicity. The Bouguer anomaly in the region varies from +44 mgals over Shillong Plateau to −255 mgals near North Lakhimpur in Assam Valley. Isostatic anomaly (Hayford) varies from +100 to −130 mgals in these areas. Over Arakan-Yoma and the Burmese plains, the isostatic anomalies vary from −20 mgals to −100 mgals. Regions of high seismicity in the area include the eastern Himalaya (including Assam syntaxis), Arakan-Yoma including the folded belt of Tripura, Irrawaddy basin, Shillong Plateau, Dauki fault and the northern part of Bengal basin. The abnormal gravity and seismicity are related to large scale tectonic movements that have taken place in the area mostly during the Cretaceous and Cenozoic times, due to interaction of the Indian, Tibetan, and Burmese plates. The high seismicity indicates that the movements are continuing. The seismic zone underlying Burma is approximately V shaped and dips toward the east underneath Arakan-Yoma. Most of the intermediate-focus earthquakes in Burma underlie the area characterized by negative isostatic anomalies, indicating the probable existence of a subduction zone underneath the Arakan-Yoma and the Burmese plains. The Shillong Plateau has a history of vertical uplift since Cretaceous times. Provided this statement is true, the uplift of the plateau preceded Himalayan tectonics starting 20 to 30 m.y. before continental India made solid contact with the Eurasian plate. The plateau is characterized by large positive isostatic anomalies as well as high seismicity. The positive isostatic anomalies may be due to intrusion or incorporation of basic material from the mantle into the crust underlying the Plateau. These intrusions may have taken place through deep seated faults such as the Dauki and could be responsible for its uplift as well.

scholarly journals An overview of the genus Anemone L. (Ranunculaceae) in India

2020 ◽  
Vol 7 (2) ◽  
pp. 136-141
Author(s):  
Pravesh Rajput ◽  
Priyanka Agnihotri
Keyword(s):  
High Altitude ◽  
Western Ghats ◽  
Conservation Status ◽  
Western Himalaya ◽  
Northeast India ◽  
Flowering Plants ◽  
Eastern Himalaya ◽  
Sustainable Utilization

The present paper documents the genus Anemone L. (Ranunculaceae) from India. A total of 26 taxa (which includes 24 species, one subspecies and one variety) has been recorded from Indo Himalayas. Western Himalaya is endowed with 9 taxa, Eastern Himalaya with 8 taxa, while 9 are common to both the flanks. Three species are present in Northeast India which are common to IHR and one species has also been reported from Western Ghats. This genus constitutes flowering plants of high altitude and maximum diversity has been observed between 2000–3000 m asl. The genus possesses high medicinal potential and needs urgent assessment of taxonomic and conservation status for its sustainable utilization.

Diversity of mosses in some underexplored regions of Manipur, Northeast India

2021 ◽  
Vol 44 (1) ◽  
Author(s):  
ASHISH KUMAR ASTHANA ◽  
VINAY SAHU ◽  
VISHAL AWASTHI
Keyword(s):  
Northeast India ◽  
Eastern Himalaya ◽  
First Time

The present paper deals with the investigation of moss taxa of some underexplored regions of Manipur, Northeast India. During the assessment of moss diversity in various localities of Manipur a total 126 species of mosses belonging to 84 genera in 34 families have been investigated and enumerated. Ten species, namely Amblystegium serpens,Entodontopsis leucostega, Entodontopsis tavoyensis, Homalia trichomanoides, Lindbergia duthiei, Philonotis mollis, Philonotis thwaitesii, Taxiphyllum giraldii,Tortella humilis and Thuidium sparsifolium are new additions to Eastern Himalaya, while 92 species of mosses have been reported for the first time from Manipur. Ten Indian endemic taxa have also been identified from the explored sites. The majority of the taxa were recorded from epiphytic habitats.

scholarly journals Effect of land-use change along altitudinal gradients on soil micronutrients in the mountain ecosystem of Indian (Eastern) Himalaya

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Burhan U. Choudhury ◽  
Meraj A. Ansari ◽  
Mahasweta Chakraborty ◽  
Thounaojam T. Meetei
Keyword(s):  
Land Use ◽  
Soil Properties ◽  
Crop Production ◽  
Acid Soils ◽  
Northeast India ◽  
Eastern Himalaya ◽  
Land Uses ◽  
Altitudinal Gradients ◽  
Mountain Ecosystem ◽  
Cu And Zn

AbstractManagement of soil micronutrients for better crop production needs a sound understanding of their status and causes of variability. This is more relevant for acid soils of the mountain ecosystem of Eastern Himalaya (Northeast India). We assessed the status, and the effect of land uses along altitudinal gradients (14 to 4090 masl) on soil properties and micronutrient concentrations (DTPA extractable Fe, Mn, Cu, and Zn) across the region. Soils varied widely in micronutrient concentrations: Fe from 0.665 to 257.1 mg kg−1 while Mn, Cu, and Zn from traces to 93.4, 17.1, and 34.2 mg kg−1, respectively. On conversion of evergreen forests (EF) to upland agriculture (Shifting—SC and Settled—SA) and plantation (PH), Mn, Cu, and Zn concentrations decreased significantly from 30.5, 1.74, and 2.13 mg kg−1 to 6.44–17.8, 0.68–0.81, and 1.06–1.42 mg kg−1, respectively. Grassland (GL) and lowland paddy (LP) had comparable Fe, Mn, and Cu concentrations (except Zn). Degradation of EF to scrubland (SL) recorded the lowest Mn (5.91 mg kg−1), Cu (0.59 mg kg−1), and Zn (0.68 mg kg−1) concentrations. Fe concentration was however increased in degraded SL (+ 73%) over EF (48.7 mg kg−1). The distribution of micronutrients among the land uses was inconsistent and followed the order: (i) Fe: SL > PH > LP > EF > GL > SC > SA, (ii) Mn: EF > GL > LP > PH > SC > SA > SL; (iii) Cu: EF > GL > LP > SC > SA = PH > SL; and (iv) Zn: GL > EF > LP > SC > SA > PH > SL. Four micronutrients responded differently and followed a non-linear, 6th—order polynomial trend along the altitudinal gradients (< 500 to 4100 masl). Peak concentrations of Fe, Mn, and Cu were recorded at 1001–2000 m while Zn was recorded at > 4000 masl. The variability (54–64%) in soil micronutrients was mainly controlled by three key soil properties: acidity, clay, and organic carbon contents. Thus, altitude-specific land-use management holds significance in the distribution of available soil micronutrients in hilly ecosystems.

scholarly journals Assessing landslide vulnerability in Kohima city, Nagaland: A geospatial approach

2020 ◽  
Vol 66 (3) ◽  
pp. 274-287
Author(s):  
Yhoshu Kedovikho ◽  
◽  
Y.V. Krishnaiah ◽  
Keyword(s):  
Meteorological Factors ◽  
Northeast India ◽  
Information Value ◽  
Vulnerability Mapping ◽  
Eastern Himalaya ◽  
Information Value Method ◽  
Gis Technique ◽  
Map Validation ◽  
Vulnerability Map ◽  
Bivariate Statistical Method

Kohima located in the Eastern Himalaya of Northeast India experience numerous landslides and soil creeps annually. Landslides, the resultant of various interactions i.e., geological, geomorphologic, meteorological factors etc., caused immense loss economically and environmentally. Kohima city experiences the torrential amount of rainfall which further aggravate landslide hazard. This paper implores the use of high-resolution satellite data for deciphering landslide vulnerability mapping through remote sensing and GIS technique. Factors such as land use and land cover, lithology, lineament, drainage, road, aspect and slope were used as thematic input layers for landslide vulnerability mapping. The bivariate statistical method particularly Information Value method was used to extract the information from the landslide and the various controlling factors to generate the landslide vulnerability map. Validation of the landslide vulnerability mapping using classification and R-index methods along with ground observation were used to create the final vulnerability map.

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