Magmatic and metamorphic history of the Proterozoic Lesser Himalayan Crystallines from Bomdila area, Arunachal Pradesh, NE Lesser Himalaya, India: Constraints from whole rock and mineral chemistry

2022 ◽  
Author(s):  
Shaik A. Rashid ◽  
Javid A Ganai ◽  
Subhadip Bhadra ◽  
Naqeebul Islam ◽  
Shamshad Ahmad
Keyword(s):  
Mineral Chemistry ◽  
Lesser Himalaya ◽  
Arunachal Pradesh ◽  
Metamorphic History ◽  
History Of

Polymetamorphism in the Archean Hemlo – Heron Bay greenstone belt, Superior Province: P–T variations and implications for tectonic evolution

1993 ◽  
Vol 30 (5) ◽  
pp. 985-996 ◽  
Author(s):  
Yuanming Pan ◽  
Michael E. Fleet
Keyword(s):  
Greenstone Belt ◽  
Regional Metamorphism ◽  
Mineral Chemistry ◽  
Superior Province ◽  
Low Grade ◽  
Garnet Porphyroblasts ◽  
Metamorphic History ◽  
Tectonic Environment ◽  
History Of ◽  
Archean Greenstone Belt

The tectono-metamorphic history of the late Archean (2800–2600 Ma) Hemlo – Heron Bay greenstone belt in the Superior Province has been delineated from textural relationships, mineral chemistry, and P–T paths in metapelites, cordierite–orthoamphibole rocks, and metabasites from the White River exploration property, Hemlo area, Ontario. An early low-temperature, medium-pressure metamorphism (about 500 °C and 6–6.5 kbar (1 kbar = 100 MPa)) is indicated by the occurrence of relict kyanite and staurolite porphyroblasts and zoned garnet porphyroblasts in metapelites and the presence of zoned calcic amphiboles in metabasites. This early metamorphism appears to have been coeval with the previously documented D1 deformation that is associated with, for example, low-angle thrusts. A second regional metamorphism predominates in the Hemlo – Heron Bay greenstone belt and is generally of relatively low grade, at about 510–530 °C and 3.2–3.5 kbar, over most of the study area and increases to medium grade (550–650 °C and 4–5 kbar) towards the southern margin with the Pukaskwa Gneissic Complex and along the central axis enclosing the Hemlo Shear Zone. The second regional metamorphism was contemporaneous with the D3 deformation and was probably related to plutonism. This type of polymetamorphism in the Hemlo – Heron Bay greenstone belt may be equivalent to those in Phanerozoic subduction complexes and therefore supports the arc–arc accretion model for the development of the southern Superior Province. Although the Hemlo – Heron Bay greenstone belt most likely represents a single tectonic environment (an oceanic island arc), the restricted occurrence of the relict kyanite and staurolite indicates that the central portion of this Archean greenstone belt probably was at a deeper crustal level at the time of the first metamorphic event.

scholarly journals Multiple Metamorphic Events Recorded within Eclogites of the Chandman District, SW Mongolia

Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 495
Author(s):  
Terbishiinkhen O. Javkhlan ◽  
Akira Takasu ◽  
Md Fazle Kabir ◽  
Dash Batulzii
Keyword(s):  
Mineral Chemistry ◽  
Orogenic Belt ◽  
Metamorphic Complex ◽  
Multiple Events ◽  
Metamorphic History ◽  
Central Asian ◽  
Lake Zone ◽  
The World ◽  
Facies Metamorphism ◽  
History Of

The eclogite-bearing Alag Khadny metamorphic complex in the Lake Zone, SW Mongolia occupies the central region of the Central Asian Orogenic Belt, the largest Phanerozoic orogenic belt in the world. The complex consists mainly of orthogneisses intercalated with eclogites and micaschists in a mélange zone. Most of eclogites are strongly amphibolitized. In this study, we examined petrography and mineral chemistry of eclogites and amphibolitized eclogites, respectively. The result of our research shows that Chandman eclogites experienced multiple events of metamorphism in throughout their subduction and subsequent collision history. We revealed that eclogites were subjected to blueschist facies metamorphism before the peak eclogite facies stage. In addition, we have studied amphibolitized eclogite, and revealed that another distinct progressive medium pressure (MP) epidote-amphibolite facies metamorphic event took place in the eclogite, consistent with collision process. The multiple events of metamorphism in eclogites have been revealed by zonation textures of HP amphiboles zoned with glaucophane→barroisite→Mg-hornblende and MP amphiboles zoned with actinolite/winchite→barroisite→Mg-hornblende/tschermakite/Fe-pargasite. These amphiboles with different zonation textures reflect their metamorphic history of subduction to collision events.

scholarly journals Zircon record of the igneous and metamorphic history of the Fiskenæsset anorthosite complex in southern West Greenland

1969 ◽  
Vol 20 ◽  
pp. 67-70 ◽  
Author(s):  
Nynke Keulen ◽  
Tomas Næraa ◽  
Thomas F. Kokfelt ◽  
John C. Schumacher ◽  
Anders Scherstén
Keyword(s):  
North Atlantic ◽  
Layered Intrusion ◽  
Mineral Chemistry ◽  
Joint Project ◽  
West Greenland ◽  
Metamorphic History ◽  
The North ◽  
History Of ◽  
The North Atlantic ◽  
North Atlantic Craton

The Fiskenæsset complex in southern West Greenland is part of the North Atlantic craton and is a layered intrusion consisting of gabbro, ultramafic and anorthositic rocks that was deformed during multiple episodes of folding and metamorphism (Myers 1985). We collected late-stage magmatic hornblenditic dykes and adjacent anorthosites and studied these samples integratively with several in situ techniques to determine the igneous and metamorphic history of the Fiskenæsset complex. The work presented here is part of an ongoing joint project between the Greenland Bureau of Minerals and Petroleum and the Geological Survey of Denmark and Greenland (GEUS). Here we report on new radiometric ages and mineral chemistry data from anorthosites from the North Atlantic craton in southern West Greenland (Fig. 1).

scholarly journals Mineral chemistry of eclogites to investigate the evolutionary metamorphic history of UHP rocks from Tso-Morari region, Ladakh, India

2010 ◽  
Vol 40 ◽  
pp. 13-20
Author(s):  
Rameshwar Rao ◽  
Hakim Rai
Keyword(s):  
High Pressures ◽  
Mineral Chemistry ◽  
Textural Features ◽  
Mineral Inclusions ◽  
Metamorphic History ◽  
Facies Metamorphism ◽  
History Of ◽  
T Path ◽  
Si Content ◽  
Tso Morari

Micro textures of metabasics from the Tso-Morari region, Ladakh were studied in order to understand the evolutionary metamorphic history of eclogites. The mineral chemistry, paragenesis of mineral inclusions in garnet, and zoning in omphacite, garnet and amphibole suggest three main metamorphic stages: (i) an eclogite stage with late blueschist facies metamorphism, (ii) a medium-pressure amphibolite facies stage, and (iii) a low-pressure amphibolite to greenschist facies stage. The high Si content in phengite, presence of rutile besides almandine-rich garnet and omphacite in eclogites indicate the attainment of high pressures. Also, the textural features and composition of amphiboles indicate that blueschist facies conditions represented by growth of glaucophane at high pressure and low temperature were followed by a lower-pressure stage of metamorphism represented by partial and in some cases complete reaction of glaucophane to calcic green amphibole such as magnesio-hornblende. The relationships define a clock-wise P-T path with the involvement of an isothermal uplift path for the eclogites and associated garnet-amphibolites of Tso-Morari region.

The Subaltern Speak- A Study On The Culture Of The Arunachalis With Special Reference To Mamang Dai’s The Legends Of Pensam

2019 ◽  
Vol 5 (4) ◽  
pp. 14-20
Author(s):  
Ms. Cheryl Antonette Dumenil ◽  
Dr. Cheryl Davis
Keyword(s):  
Special Reference ◽  
Small World ◽  
Natural World ◽  
Arunachal Pradesh ◽  
North East India ◽  
North East ◽  
Shared History ◽  
History Of ◽  
And Gender ◽  
Insight Into

North- East India is an under veiled region with an awe-inspiring landscape, different groups of ethnic people, their culture and heritage. Contemporary writers from this region aspire towards a vision outside the tapered ethnic channel, and they represent a shared history. In their writings, the cultural memory is showcased, and the intensity of feeling overflows the labour of technique and craft. Mamang Dai presents a rare glimpse into the ecology, culture, life of the tribal people and history of the land of the dawn-lit mountains, Arunachal Pradesh, through her novel The Legends of Pensam. The word ‘Pensam’ in the title means ‘in-between’,  but it may also be interpreted as ‘the hidden spaces of the heart’. This is a small world where anything can happen. Being adherents of the animistic faith, the tribes here believe in co-existence with the natural world along with the presence of spirits in their forests and rivers. This paper attempts to draw an insight into the culture and gender of the Arunachalis with special reference to The Legends of Pensam by Mamang Dai.

The Metasomatized Mantle beneath the North Atlantic Craton: Insights from Peridotite Xenoliths of the Chidliak Kimberlite Province (NE Canada)

2019 ◽  
Vol 60 (10) ◽  
pp. 1991-2024 ◽  
Author(s):  
M G Kopylova ◽  
E Tso ◽  
F Ma ◽  
J Liu ◽  
D G Pearson
Keyword(s):  
North Atlantic ◽  
Thermal State ◽  
Mineral Chemistry ◽  
Mantle Metasomatism ◽  
Labrador Sea ◽  
The North ◽  
Rock Types ◽  
History Of ◽  
The North Atlantic ◽  
North Atlantic Craton

Abstract We studied the petrography, mineralogy, thermobarometry and whole-rock chemistry of 120 peridotite and pyroxenite xenoliths collected from the 156–138 Ma Chidliak kimberlite province (Southern Baffin Island). Xenoliths from pipes CH-1, -6, -7 and -44 are divided into two garnet-bearing series, dunites–harzburgites–lherzolites and wehrlites–olivine pyroxenites. Both series show widely varying textures, from coarse to sheared, and textures of late formation of garnet and clinopyroxene. Some samples from the lherzolite series may contain spinel, whereas wehrlites may contain ilmenite. In CH-6, rare coarse samples of the lherzolite and wehrlite series were derived from P = 2·8 to 5·6 GPa, whereas predominant sheared and coarse samples of the lherzolite series coexist at P = 5·6–7·5 GPa. Kimberlites CH-1, -7, -44 sample mainly the deeper mantle, at P = 5·0–7·5 GPa, represented by coarse and sheared lherzolite and wehrlite series. The bulk of the pressure–temperature arrays defines a thermal state compatible with 35–39 mW m–2 surface heat flow, but a significant thermal disequilibrium was evident in the large isobaric thermal scatter, especially at depth, and in the low thermal gradients uncharacteristic of conduction. The whole-rock Si and Mg contents of the Chidliak xenoliths and their mineral chemistry reflect initial high levels of melt depletion typical of cratonic mantle and subsequent refertilization in Ca and Al. Unlike the more orthopyroxene-rich mantle of many other cratons, the Chidliak mantle is rich (∼83 vol%) in forsteritic olivine. We assign this to silicate–carbonate metasomatism, which triggered wehrlitization of the mantle. The Chidliak mantle resembles the Greenlandic part of the North Atlantic Craton, suggesting the former contiguous nature of their lithosphere before subsequent rifting into separate continental fragments. Another, more recent type of mantle metasomatism, which affected the Chidliak mantle, is characterized by elevated Ti in pyroxenes and garnet typical of all rock types from CH-1, -7 and -44. These metasomatic samples are largely absent from the CH-6 xenolith suite. The Ti imprint is most intense in xenoliths derived from depths equivalent to 5·5–6·5 GPa where it is associated with higher strain, the presence of sheared samples of the lherzolite series and higher temperatures varying isobarically by up to 200 °C. The horizontal scale of the thermal-metasomatic imprint is more ambiguous and could be as regional as tens of kilometers or as local as <1 km. The time-scale of this metasomatism relates to a conductive length-scale and could be as short as <1 Myr, shortly predating kimberlite formation. A complex protracted metasomatic history of the North Atlantic Craton reconstructed from Chidliak xenoliths matches emplacement patterns of deep CO2-rich and Ti-rich magmatism around the Labrador Sea prior to the craton rifting. The metasomatism may have played a pivotal role in thinning the North Atlantic Craton lithosphere adjacent to the Labrador Sea from ∼240 km in the Jurassic to ∼65 km in the Paleogene.

Tectono-metamorphic history of the ophiolitic Lento unit (northern Corsica): evidences for the complexity of accretion-exhumation processes in a fossil subduction system

2007 ◽  
Vol 20 (1-2) ◽  
pp. 99-118 ◽  
Author(s):  
Nicola Levi ◽  
Alessandro Malasoma ◽  
Michele Marroni ◽  
Luca Pandolfi ◽  
Matteo Paperini
Keyword(s):  
Metamorphic History ◽  
History Of ◽  
Subduction System

scholarly journals Reconstructing the exhumation history of the Lesser Himalaya, NW India, from a multitechnique provenance study of the foreland basin Siwalik Group

Tectonics ◽  
2009 ◽  
Vol 28 (5) ◽  
pp. n/a-n/a ◽  
Author(s):  
Yani Najman ◽  
Mike Bickle ◽  
Eduardo Garzanti ◽  
Malcolm Pringle ◽  
Dan Barfod ◽  
...  
Keyword(s):  
Foreland Basin ◽  
Provenance Study ◽  
Lesser Himalaya ◽  
History Of ◽  
Siwalik Group ◽  
Exhumation History

scholarly journals Monazite U–Th–Pb geochronology of the Central Metasedimentary Belt Boundary Zone (CMBbz), Grenville Province, Ontario Canada

2018 ◽  
Vol 55 (9) ◽  
pp. 1063-1078 ◽  
Author(s):  
Michelle J. Markley ◽  
Steven R. Dunn ◽  
Michael J. Jercinovic ◽  
William H. Peck ◽  
Michael L. Williams
Keyword(s):  
Shear Zone ◽  
Crustal Thickening ◽  
Boundary Zone ◽  
Grenville Province ◽  
Metamorphic History ◽  
Crustal Thinning ◽  
Tectonic Significance ◽  
History Of ◽  
Central Gneiss Belt ◽  
Scale Shear

The Central Metasedimentary Belt boundary zone (CMBbz) is a crustal-scale shear zone that juxtaposes the Central Gneiss Belt and the Central Metasedimentary Belt of the Grenville Province. Geochronological work on the timing of deformation and metamorphism in the CMBbz is ambiguous, and the questions that motivate our study are: how many episodes of shear zone activity did the CMBbz experience, and what is the tectonic significance of each episode? We present electron microprobe data from monazite (the U–Th–Pb chemical method) to directly date deformation and metamorphism recorded in five garnet–biotite gneiss samples collected from three localities of the CMBbz of Ontario (West Guilford, Fishtail Lake, and Killaloe). All three localities yield youngest monazite dates ca. 1045 Ma; most of the monazite domains that yield these dates are high-Y rims. In comparison with this common late Ottawan history, the earlier history of the three CMBbz localities is less clearly shared. The West Guilford samples have monazite grain cores that show older high-Y domains and younger low-Y domains; these cores yield a prograde early Ottawan (1100–1075 Ma) history. The Killaloe samples yield a well-defined prograde, pre- to early Shawinigan history (i.e., 1220–1160 Ma) in addition to some evidence for a second early Ottawan event. In other words, the answers to our research questions are: three events; a Shawinigan event possibly associated with crustal thickening, an Ottawan event possibly associated with another round of crustal thickening, and a late Ottawan event that resists simple interpretation in terms of metamorphic history but that coincides chronologically with crustal thinning at the base of an orogenic lid.

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