Depositional environment of Upper Paleocene – Middle Eocene series of the Lesser Himalaya, Central Nepal

Lithos ◽  
2021 ◽  
Vol 388-389 ◽  
pp. 106060
Author(s):  
Bhupati Neupane ◽  
Junmeng Zhao ◽  
Babu Ram Gyawali ◽  
Yan Deng ◽  
Bishal Maharjan ◽  
...  
Keyword(s):  
Depositional Environment ◽  
Middle Eocene ◽  
Lesser Himalaya ◽  
Central Nepal ◽  
Upper Paleocene

Sedimentary Cyclicity in the Upper Paleocene- Eocene Successions of the Haymana Basin (Ankara, Turkey): Responses of Fossils to Cyclicity

2020 ◽  
Author(s):  
Nilya Bengül
Keyword(s):  
Depositional Environment ◽  
Middle Eocene ◽  
Planktonic Foraminifera ◽  
High Energy ◽  
Central Anatolia ◽  
Accretionary Wedge ◽  
Depositional Model ◽  
Stratigraphic Sequence ◽  
Large Benthic Foraminifera ◽  
Upper Paleocene

<p>The Haymana Basin in central Anatolia (Turkey) formed during the closure of the Neo-Tethys on Late Cretaceous to Middle Eocene as a forearc accretionary wedge. Late Paleocene to Middle Eocene aged units in this basin are exposed near Çayraz Village, Haymana. The Çayraz Formation is the youngest unit of the Haymana Basin, and it is represented by packages of nummulitic banks, and the intercalation of calcareous mudstones. The aim of this study is to investigate the sedimentary cyclicity and depositional sequences in the Upper Paleocene- Eocene successions of the Haymana Basin. To be able to achieve this objective, a stratigraphic section has been measured through this succession. In this study, detailed microfacies analyses of the shallow-water carbonate successions indicate a ramp type depositional model of the carbonate rocks. The facies composed of Alveolina sp., Orbitolites sp., and  Miliolids that indicate low energy depositional environment . After that depositional environment to  the shoal; the facies composed of Nummulites spp., Assilina spp. occur and increase their abundance towards high-energy environments. Absence of the Alveolina sp., Orbitolites sp., and Miliolids. occur in accordance with that. The facies composed of Nummulites spp., Assilina spp. become associated with Discocyclina sp. towards to open sea on the ramp, and the shallow open marine part is represented by the shale with the association of planktonic foraminifera. Lateral relationships of the facies from proximal (inner ramp) to the distal (mid ramp) part of the ramp are investigated by using the knowledge of paleoecology preferences of the fossils, lithologic data of the rocks and biological aspects of the fossils.  The fossil associations and their indicator environments can be used in vertical changes of the facies as in the lateral relationships of the facies. It has potential to derive cyclic relationships of the stratigraphic sequence. Therefore, based on the detailed microfacies analysis and change in the distribution of the fossil associations in the stacking pattern of the sequence, a composite depositional model has been suggested. At this part of the research newly acquired question is that the driven factor of these cyclic relationships of the sequence, whether it occurred by the control of the eustatic sea- level or the interplay between tectonics and the eustacy as the dominating factor in the sequence formation.</p><p> </p><p>Keywords: Large Benthic Foraminifera, Nummulites spp., Assilina spp., Haymana Basin, Çayraz Formation</p>

Middle Eocene‐Oligocene anatexis and exhumation of the Greater Himalayan Sequence in central Nepal

Terra Nova ◽  
2021 ◽  
Author(s):  
Zhiqin Xu ◽  
Qin Wang ◽  
Hanwen Dong ◽  
Hui Cao ◽  
Guangwei Li ◽  
...  
Keyword(s):  
Middle Eocene ◽  
Central Nepal ◽  
Greater Himalayan Sequence

scholarly journals Occurrences of mineral resources in Bandipur Gondrang area of Tanahun district, central Nepal, Lesser Himalaya

2014 ◽  
Vol 2 ◽  
pp. 24-35
Author(s):  
Kabiraj Paudyal
Keyword(s):  
Mineral Resources ◽  
Mineral Deposits ◽  
Lesser Himalaya ◽  
Geological Investigation ◽  
Central Nepal ◽  
Metallic Mineral ◽  
Geological Map ◽  
Geological Control ◽  
Basic Rocks

A detailed geological investigation was carried out to assess the distribution of minerals and their geological control in Bandipur-Gondrang area of Tanahu district, a part of Lesser Himalaya in central Nepal. The area is found rich in both metallic and non-metallic mineral deposits. The main metallic minerals found are iron in Phalamdada and Labdi Khola, copper in Bhut Khola and poly-metallic deposits including suspected gold in Bhangeri Khola and Jaubari Khola-Bar Khola sections. A large deposit of inorganic carbon is found around the Gondrang-Watak area. Similarly, a good quality of green marble (metabasite) is found as decorative stone in Bagar Khola area and good quality of roofing stone in Bandipur area. In addition to these economic deposits other several sub economic to non-economic mineral are also located in the geological map of the area. Categorization of these mineral deposits is based on the probable reserve and laboratory analysis of related samples. Geological control of mineral deposits is considered to be the stratigraphic, structural, metamorphic and hydrothermal. Iron mineralization of the area is found stratigraphical control, copper deposits by magmatism of basic rocks (amphibolites), and poly-metallic deposits are related to the hydrothermal processes.

scholarly journals Distribution of boron in the rocks of central Nepal Himalaya

2003 ◽  
Vol 28 ◽  
Author(s):  
Santa Man Rai
Keyword(s):  
Partial Melting ◽  
Boron Content ◽  
Lesser Himalaya ◽  
Main Central Thrust ◽  
Nepal Himalaya ◽  
Metasedimentary Rocks ◽  
Central Nepal ◽  
Very High

Boron content in the rocks of central Nepal Himalaya depends upon the lithology and the grade of metamorphism. The concentration of boron is abundant (up to 322 ppm) in the metasedimentary rocks of the Lesser Himalaya. There seems to be a rather good correlation between the boron content in the rocks and the grade of metamorphism. The boron content progressively increases from chlorite to garnet isograds, then it systematically decreases in the staurolite±kyanite, kyanite and sillimanite isograds, respectively. This trend may be related to the inverse metamorphism associated with movement along the Main Central Thrust. The Manaslu leucogranite contains very high amount of boron (950 ppm). The enrichment of boron in this rock may be due to the release of boron from the Lesser Himalayan rocks during the partial melting of the Higher Himalayan Crystallines (Tibetan Slab) as a result of the movement along the MCT. Tourmaline from the Manaslu Granite is also highly rich in boron (8460 ppm).

scholarly journals Geology and Mineral Resources of Phalamdada-Dhuwakot Section of West-Central Nepal, Lesser Himalaya

2018 ◽  
pp. 59-64
Author(s):  
Arjun Bhattarai ◽  
Kabiraj Paudyal
Keyword(s):  
Mineral Resources ◽  
Geological Mapping ◽  
Metamorphic Rocks ◽  
Low Grade ◽  
Lesser Himalaya ◽  
Central Nepal ◽  
West Central ◽  
Metallic Mineral ◽  
Geological Control ◽  
Core Part

Geological mapping was carried out along the Phalamdanda-Dhuwakot section of west-central Nepal in the Lesser Himalaya. The aim of geological mapping was to prospect the metallic mineral resources in the area especially to assess the geological control of mineralization as prognostic mapping and study the genesis of mineralization. The area has developed low-grade metamorphic rocks of the Nawakot Group. Geological rock units like the Kuncha Formation, Fagfog Quartzite, Dandagaon Phyllite, Nourpul Formation and Dhading Dolomite are mapped in the area. Jal Bhanjyang Thrust carries the more older rocks of the Nourpul Formation over the Dhading Dolomite. The area is highly deformed as indicated by presence of folds. Outliers of Fagfog Quartzite and Dhading Dolomite are developed at the core part of the syncline. Phalamdada iron and Anbu Khaireni as well as Dharapani copper are the major metallic deposits reported in the area. Both deposits are considered as the syngenetic in nature. Bulletin of Department of Geology, vol. 20-21, 2018, pp:59-64

scholarly journals Lithofacies and depositional environment of the Siwalik Group in Samari-Sukaura River area, Central Nepal

2013 ◽  
Vol 16 ◽  
pp. 53-64 ◽  
Author(s):  
Dev Kumar Syangbo ◽  
Naresh Kazi Tamrakar
Keyword(s):  
Depositional Environment ◽  
Foreland Basin ◽  
River System ◽  
Nepal Himalaya ◽  
Meandering River ◽  
Fine Grained ◽  
Architectural Elements ◽  
Central Nepal ◽  
Eastern Zone ◽  
Siwalik Group

Thick sedimentary sequence deposited in the foreland basin of the Nepal Himalaya is represented by the Siwalik Group. The Siwalik Group is well exposed in the Samari-Sukaura River area. The present study is focused in southern portion of the MBT around the Samari-Sukaura area for its depositional environment. The Middle Siwaliks of the Sukaura Road sections is overlained by the Lower Siwaliks which is separated by the Karki Khola Thrust. Extension of the Lower Siwaliks in the Jyamire Khola and the Bundal Khola becomes wider in the eastern Zone. Repetition of the Lower Siwaliks along the southern margin of the MBT is recognized. Depending on lithofacies assemblage and facies analysis, the two broad facies assemblages FA1 and FA2 have been distinguished. FA1 shows SB, FF, LA, LS and CH architectural elements and is interpreted as a product of the fine-grained meandering river system. FA2 shows SB, FF, LA, DA and CH architectural elements and is interpreted as a product of sandy mixed-load meandering river system. DOI: http://dx.doi.org/10.3126/bdg.v16i0.8884   Bulletin of the Department of Geology Vol. 16, 2013, pp. 53-64

Age of metamorphism in the Lesser Himalaya and the Main Central Thrust zone, Garhwal India: results of illite crystallinity,40Ar–39Ar fusion and K–Ar studies

1995 ◽  
Vol 132 (2) ◽  
pp. 139-149 ◽  
Author(s):  
G. J. H. Oliver ◽  
M. R. W. Johnson ◽  
A. E. Fallick
Keyword(s):  
Regional Metamorphism ◽  
Low Grade ◽  
Supporting Evidence ◽  
Lesser Himalaya ◽  
Main Central Thrust ◽  
Illite Crystallinity ◽  
Lower Eocene ◽  
Thrust Zone ◽  
Lower Palaeozoic ◽  
Upper Paleocene

AbstractIllite crystallinity data from the Lesser Himalaya of Garhwal show that the upper Paleocene-lower Eocene Subathu Formation, deposited immediately prior to or early in the Himalayan collision, has not suffered significant regional metamorphism. The regional metamorphism in the upper Precambrian–lower Palaeozoic Lesser Himalaya must therefore be precollisional. Illite crystallinity results from Lesser Himalayan fossiliferous Permian strata show grades of metamorphism intermediate between upper Paleocene–lower Eocene and Proterozoic–lower Palaeozoic strata indicating a pre-Permian regional metamorphism for the latter.K–Ar whole rock cooling ages provide supporting evidence for pre-collisional regional metamorphism in the Lesser Himalaya. Slates and phyllites below the Main Central Thrust (MCT) show pre-Cenozoic whole rock ages, as old as Ordovician (486 Ma). Whilst resetting of K–Ar whole rock ages has occurred locally in pervasively cleaved Palaeozoic strata (near thrusts?), fracture cleaved Permian and upper Paleocene–lower Eocene sediments give whole rock ages compatible with diagenesis. The illite crystallinity results confirm that these sediments have not been heated above mica blocking temperatures.Muscovite40Ar–39Ar and K–Ar mineral ages within the 5 km thick MCT zone are as young as 8 Ma indicating that temperatures of above ~ 350°C were maintained in the MCT zone for over 10 Ma after high temperature (~ 550°C) shearing on the MCT. This heating did not affect the MCT footwall Lesser Himalaya to any regional extent, where pre-Permian low grade regional metamorphism has not been overprinted.

scholarly journals Petrography and illite crystallinity of the Lesser Himalayan metasediments, Gorkha Narayangarh section, central Nepal

1970 ◽  
Vol 14 ◽  
pp. 67-76
Author(s):  
Kabi Raj Paudyal ◽  
Tara Prasad Pokharel ◽  
Lalu Prasad Paudel
Keyword(s):  
Systematic Study ◽  
The Other ◽  
Lesser Himalaya ◽  
Illite Crystallinity ◽  
The North ◽  
Central Nepal

Geological study was carried out in the Lesser Himalaya from Gorkha-Narayangarh section of central Nepal aiming to assessthe metamorphism of the area. The area consists of the Kunchha Formation, Fagfog Quartzite, Dandagaon Phyllites, NourpulFormation, Dhading Dolomite, Benighat Slate and the Robang Formation of the Nawakot Complex. Systematic study onpetrography and illite crystallinity was performed in the samples representing all types of lithology and formations. Bothpetrography and illite crystallinity show that the rocks south of Anbu Khaireni belong to chlorite zone. Biotite and garnet zonesare observed only in the north of Anbu Khaireni. The metamorphic zones are inverted as in the other parts of the Lesser Himalaya.DOI: http://dx.doi.org/10.3126/bdg.v14i0.5441Bulletin of the Department of Geology Vol.14 2011, pp.67-76 

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