Origin of the island arc Moho transition zone via melt-rock reaction and its implications for intracrustal differentiation of island arcs: Evidence from the Jijal complex (Kohistan complex, northern Pakistan)

Geology ◽  
2007 ◽  
Vol 35 (8) ◽  
pp. 683 ◽  
Author(s):  
Carlos J. Garrido ◽  
Jean-Louis Bodinier ◽  
Bruno Dhuime ◽  
Delphine Bosch ◽  
Ingrid Chanefo ◽  
...  
Keyword(s):  
Transition Zone ◽  
Island Arc ◽  
Northern Pakistan ◽  
Island Arcs

scholarly journals Tectonic reconstruction of Uda-Murgal arc and the Late Jurassic and Early Cretaceous convergent margin of Northeast Asia–Northwest Pacific

2009 ◽  
Vol 4 ◽  
pp. 273-288 ◽  
Author(s):  
S. D. Sokolov ◽  
G. Ye. Bondarenko ◽  
A. K. Khudoley ◽  
O. L. Morozov ◽  
M. V. Luchitskaya ◽  
...  
Keyword(s):  
Northeast Asia ◽  
Upper Jurassic ◽  
Island Arc ◽  
Passive Margin ◽  
Northwest Pacific ◽  
Island Arcs ◽  
The South ◽  
Convergent Margin ◽  
Tectonic Zone ◽  
The North

Abstract. A long tectonic zone composed of Upper Jurassic to Lower Cretaceous volcanic and sedimentary rocks is recognized along the Asian continent margin from the Mongol-Okhotsk fold and thrust belt on the south to the Chukotka Peninsula on the north. This belt represents the Uda-Murgal arc, which was developed along the convergent margin between Northeast Asia and Northwest Meso-Pacific. Several segments are identified in this arc based upon the volcanic and sedimentary rock assemblages, their respective compositions and basement structures. The southern and central parts of the Uda-Murgal arc were a continental margin belt with heterogeneous basement represented by metamorphic rocks of the Siberian craton, the Verkhoyansk terrigenous complex of Siberian passive margin and the Koni-Taigonos Late Paleozoic to Early Mesozoic island arc with accreted oceanic terranes. At the present day latitude of the Pekulney and Chukotka segments there was an ensimatic island arc with relicts of the South Anyui oceanic basin in a backarc basin. Accretionary prisms of the Uda-Murgal arc and accreted terranes contain fragments of Permian, Triassic to Jurassic and Jurassic to Cretaceous (Tithonian–Valanginian) oceanic crust and Jurassic ensimatic island arcs. Paleomagnetic and faunal data show significant displacement of these oceanic complexes and the terranes of the Taigonos Peninsula were originally parts of the Izanagi oceanic plate.

scholarly journals Exposed crustal cross section of the "Kohistan paleo-island arc", northern Pakistan

1996 ◽  
Vol 102 (9) ◽  
pp. XXIII-XXVI
Author(s):  
Takashi Nakajima ◽  
Sakae Sano ◽  
Teruo Shirahase
Keyword(s):  
Cross Section ◽  
Island Arc ◽  
Northern Pakistan

Subduction-related magmatic imprint of most Philippine ophiolites: implications on the early geodynamic evolution of the Philippine archipelago

2004 ◽  
Vol 175 (5) ◽  
pp. 443-460 ◽  
Author(s):  
Rodolfo A. Tamayo* ◽  
René C. Maury* ◽  
Graciano P. Yumul ◽  
Mireille Polvé ◽  
Joseph Cotten ◽  
...  
Keyword(s):  
Partial Melting ◽  
Subduction Zone ◽  
Volcanic Rocks ◽  
The Philippines ◽  
Island Arc ◽  
Island Arcs ◽  
Geodynamic Evolution ◽  
Wide Range ◽  
Opening And Closing ◽  
Back Arc

Abstract The basement complexes of the Philippine archipelago include at least 20 ophiolites and ophiolitic complexes. These complexes are characterised by volcanic sequences displaying geochemical compositions similar to those observed in MORB, transitional MORB-island arc tholeiites and arc volcanic rocks originating from modern Pacific-type oceans, back-arc basins and island arcs. Ocean island basalt-like rocks are rarely encountered in the volcanic sequences. The gabbros from the ophiolites contain clinopyroxenes and plagioclases showing a wide range of XMg and An values, respectively. Some of these gabbros exhibit mineral chemistries suggesting their derivation from basaltic liquids formed from mantle sources that underwent either high degrees of partial melting or several partial melting episodes. Moreover, some of the gabbros display a crystallization sequence where orthopyroxene and clinopyroxene appeared before plagioclase. The major element compositions of coexisting orthopyroxenes and olivines from the mantle peridotites are consistent with low to high degrees of partial melting. Accessory spinels in these peridotites display a wide range of XCr values as well with some of them above the empirical upper limit of 0.6 often observed in most modern mid-oceanic ridge (MOR) mantle rocks. Co-existing olivines and spinels from the peridotites also exhibit compositions suggesting that they lastly equilibrated under oxidizing mantle conditions. The juxtaposition of volcanic rocks showing affinities with modern MOR and island arc environments suggests that most of the volcanic sequences in Philippine ophiolites formed in subduction-related geodynamic settings. Similarly, their associated gabbros and peridotites display mineralogical characteristics and mineral chemistries consistent with their derivation from modern supra-subduction zone-like environments. Alternatively, these rocks could have, in part, evolved in a supra-subduction zone even though they originated from a MOR-like setting. A simplified scenario regarding the early geodynamic evolution of the Philippines is proposed on the basis of the geochemical signatures of the ophiolites, their ages of formation and the ages and origins of the oceanic basins actually bounding the archipelago, including basins presumed to be now totally consumed. This scenario envisages the early development of the archipelago to be largely dominated by the opening and closing of oceanic basins. Fragments of these basins provided the substratum on top of which the Cretaceous to Recent volcanic arcs of the Philippines were emplaced.

Lithogeochemistry of volcano-plutonic assemblages of the southern Hanson Lake Block and southeastern Glennie Domain, Trans-Hudson Orogen: evidence for a single island arc complex

1999 ◽  
Vol 36 (2) ◽  
pp. 209-225 ◽  
Author(s):  
Ralf O Maxeiner ◽  
Tom II Sibbald ◽  
William L Slimmon ◽  
Larry M Heaman ◽  
Brian R Watters
Keyword(s):  
Volcanic Rocks ◽  
Volcanic Belt ◽  
Oceanic Island ◽  
Island Arc ◽  
Island Arcs ◽  
Calc Alkaline ◽  
East Central ◽  
South Central ◽  
Volcaniclastic Rocks ◽  
Flin Flon

This paper describes the geology, geochemistry, and age of two amphibolite facies volcano-plutonic assemblages in the southern Hanson Lake Block and southeastern Glennie Domain of the Paleoproterozoic Trans-Hudson Orogen of east-central Saskatchewan. The Hanson Lake assemblage comprises a mixed suite of subaqueous to subaerial dacitic to rhyolitic (ca. 1875 Ma) and intercalated minor mafic volcanic rocks, overlain by greywackes. Similarly with modern oceanic island arcs, the Hanson Lake assemblage shows evolution from primitive arc tholeiites to evolved calc-alkaline arc rocks. It is intruded by younger subvolcanic alkaline porphyries (ca. 1861 Ma), synvolcanic granitic plutons (ca. 1873 Ma), and the younger Hanson Lake Pluton (ca. 1844 Ma). Rocks of the Northern Lights assemblage are stratigraphically equivalent to the lower portion of the Hanson Lake assemblage and comprise tholeiitic arc pillowed mafic flows and felsic to intermediate volcaniclastic rocks and greywackes, which can be traced as far west as Wapawekka Lake in the south-central part of the Glennie Domain. The Hanson Lake volcanic belt, comprising the Northern Lights and Hanson Lake assemblages, shows strong lithological, geochemical, and geochronological similarities to lithotectonic assemblages of the Flin Flon Domain (Amisk Collage), suggesting that all of these areas may have been part of a more or less continuous island arc complex, extending from Snow Lake to Flin Flon, across the Sturgeon-Weir shear zone into the Hanson Lake Block and across the Tabbernor fault zone into the Glennie Domain.

The Thores volcanic island arc of the Pearya Terrane from Ellesmere Island formed on Precambrian continental crust

2021 ◽  
Author(s):  
Jarosław Majka ◽  
Karolina Kośmińska ◽  
Jakub Bazarnik ◽  
William C. McClelland
Keyword(s):  
Continental Crust ◽  
High Arctic ◽  
Sensu Stricto ◽  
Ellesmere Island ◽  
Island Arc ◽  
Fault System ◽  
Published Data ◽  
Island Arcs ◽  
Volcanic Island ◽  
National Science

<p>We report on U-Pb zircon dating and bulk rock geochemistry results of intermediate to felsic rocks of the Thores Suite of the Pearya Terrane, northern Ellesmere Island (Arctic Canada).  Our new results together with the previously published data show that the Thores Suite was formed in the Early Ordovician (c. 490-470 Ma) as a part of an island arc. Some of the dated samples revealed common xenocrystic zircon. The latter yielded ages ranging between c. 2690 Ma and c. 520 Ma. The obtained ages of xenocrystic zircon are interpreted to be typical of Laurentia. We propose that the youngest obtained cluster of ages c. 580-570 Ma expresses a component typical for the Timanide Orogen, which is conventionally tied to Baltica. The newdataset sheds light on the history and understanding of the Thores Suite, which used to be explained as an effect of the M’Clintock orogenesis. The latter event was commonly presented as foreign to the major Caledonian orogenesis sensu stricto. In our view, the Thores Suite represents an island arc, which was formed on a fragment of continental crust dismembered during Iapetus opening. Importantly, the age of the Thores island arc is coeval with other island arcs and high pressure metamorphic units of the Scandinavian and Svalbard Caledonides. Thus, it is likely that the Thores volcanic island arc was a part of the larger arc system operating within northern Iapetus. The juxtaposition of the Thores arc with the other successions of the Pearya Terrane is ascribed to a major sinistral strike-slip escape fault-system developed along the northeastern margins of Baltica and Laurentia, broadly concurrent with the main Scandian collision between the two aforementioned continents. This crustal scale fault structure enabled the juxtaposition of numerous crustal blocks of different Precambrian ancestry that can be found in various regions of the current High Arctic, including Svalbard, Greenland and Ellesmere Island.</p><p>This research was supported by the National Science Centre (Poland) project no. 2015/17B/ST10/03114 and the internal AGH-UST funding to J. Majka, the internal grant of the Polish Geological Institute - NRI no. 62.9012.2014.00.0 to J. Bazarnik and the National Science Foundation (USA) grant EAR1650022 to J. Gilotti and W. McClelland.</p>

scholarly journals The Kohistan between Gilgit and Chilas, northern Pakistan: regional tectonic implications

1996 ◽  
Vol 14 ◽  
Author(s):  
T. Khan ◽  
M. A. Khan ◽  
M. Q. Jan ◽  
M. Latif
Keyword(s):  
Sedimentary Rocks ◽  
Oceanic Island ◽  
Island Arc ◽  
Northern Pakistan ◽  
The Past ◽  
Volcanic Group ◽  
The North ◽  
Regional Tectonic ◽  
Back Arc ◽  
Field Geology

In this paper, we present geological description of an area located between Gilgit and Chilas within the Kohistan terrane. This terrane has been considered an intra-oceanic island arc, formed due to northward subduction of the Neo-tethyan lithospheric plate. At present, it is squeezed between the Karakoram­ Asian and Indian continental plates. Both the contacts are marked by suture zones, that is, Shyok (MKT) in the north and Indus (MMT) sutures in the south, respectively. The investigated area consists of plutonic, metamorphosed volcanic and sedimentary rocks, the Chilas Complex, and the Kamila Amphibolite. The metamorphosed volcanic and sedimentary rocks are packaged into the Jagfot Group. This group comprises basal turbiditic sediments, intercalated with amphibolites and calc-silicates (the Gilgit Formation), followed upward by the Gashu-Confluence Volcanics = Chait Volcanic Group, and finally the Thelichi Formation = Yasin Group of Aptian-Albian age. The Thelichi Formation comprises a volcanic base (Majne volcanics) and overlying turbidites, local intercalation of marbles, volcaniclastics and lava flows. Greenschist and amphibolite facies are common in the Jaglot Group, and particularly the sillimanite in the Gilgit Formation. A pair of anticline (the Gilgit anticline) and syncline (the Jaglot syncline) make up the structural scenario. On the basis of field geology, we conclude that the entire Jaglot Group and its equivalents, the Yasin Group, Chait Volcanic Group in Kohistan, and Burjila Formation, Bauma Harel Formation and Katzarah Formation in Ladakh show intra-oceanic back-arc basin rather than island arc affinities as suggested in the past.

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