Geochemical modelling of the Chilas Complex in the Kohistan Terrane, northern Pakistan

Takahashi, Yutaka; Mikoshiba, Masumi; Takahashi, Yasuhiro; Kausar, Allah Bakhsh; Khan, Tahseenullah; Kubo, Katashi

doi:10.1016/j.jseaes.2006.04.007

Cited by 26 publications

(16 citation statements)

References 22 publications

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“…Only one representative pattern for each type of granite is plotted in (b). The trace element patterns of the Type-3 rocks are similar to those of gabbros and diorites from the Chilas complex (Jagoutz et al, 2006;Takahashi et al, 2006…”

Section: Plutonic-volcanic Rocksmentioning

confidence: 59%

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Geochemical Architecture of the Lower- to Middle-crustal Section of a Paleo-island Arc (Kohistan Complex, Jijal–Kamila Area, Northern Pakistan): Implications for the Evolution of an Oceanic Subduction Zone

Dhuime

Bosch

Garrido

et al. 2009

Journal of Petrology

106

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Section: Plutonic-volcanic Rocksmentioning

confidence: 59%

“…Trace element patterns of the gabbros and diorites from the Chilas complex (Jagoutz et al, 2006;Takahashi et al, 2006) are reported in the inset of Fig. 4b for comparison.…”

Section: Plutonic-volcanic Rocksmentioning

confidence: 99%

Geochemical Architecture of the Lower- to Middle-crustal Section of a Paleo-island Arc (Kohistan Complex, Jijal–Kamila Area, Northern Pakistan): Implications for the Evolution of an Oceanic Subduction Zone

Dhuime

Bosch

Garrido

et al. 2009

Journal of Petrology

106

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“…Magmatic rock compositions of the Famatinian arc are from Otamendi et al (2009aOtamendi et al ( ,b, 2010aOtamendi et al ( ,b, 2012 and Walker Jr et al (2015). Rock compositions of the Kohistan arc are summarized in Jagoutz et al (2011) and are based on the works of Jan and Howie (1981), Khan (1988), Miller and Christensen (1994), Yamamoto and Yoshino (1998), Shah and Shervais (1999), Mikoshiba et al (1999), Rolland et al (2002), Bignold and Treloar (2003), Garrido et al (2006), Jagoutz et al (2006Jagoutz et al ( , 2011, Takahashi et al (2007) and Dhuime et al (2007Dhuime et al ( , 2009. Table 1) with increasing temperatures (P = 0.8 GPa).…”

Section: Fig 19mentioning

confidence: 99%

Insights into the Compositional Evolution of Crustal Magmatic Systems from Coupled Petrological-Geodynamical Models

Rummel

Kaus

Baumann

et al. 2020

Journal of Petrology

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The evolution of crustal magmatic systems is incompletely understood, as most studies are limited either by their temporal or spatial resolution. Exposed plutonic rocks represent the final stage of a long-term evolution punctuated by several magmatic events with different chemistry and generated under different mechanical conditions. Although the final state can be easily described, the nature of each magmatic pulse is more difficult to retrieve. This study presents a new method to investigate the compositional evolution of plutonic systems while considering thermal and mechanical processes. A thermomechanical code (MVEP2) extended by a semi-analytical dike/sill formation algorithm, is combined with a thermodynamic modelling approach (Perple_X) to investigate the feedback between petrology and mechanics. Melt is extracted to form dikes while depleting the source region. The evolving rock compositions are tracked on markers using a different phase diagram for each discrete bulk-rock composition. The rock compositional evolution is thus tracked with a high precision by means of a database with more than 58,000 phase diagrams. This database describes how density, melt fraction, chemical composition of melt and solid fractions and mineralogical assemblages change over crustal to uppermost mantle P-T conditions for a large range of rock compositions. Each bulk rock composition is composed of the 10 major oxides (SiO2-TiO2-Al2O3-Cr2O3-MgO-FeO-CaO-Na2O-K2O-H2O) including an oxygen buffer. The combined modelling approach is applied to study the chemical evolution of the crust during arc magmatism and related melt extraction and magma mixing processes. Basaltic sills are periodically injected into the crust to model heat/magma influx from the mantle. We find that accumulated sills turn into long-lived mush chambers when using a lower rock cohesion or assuming a higher intrusion depth. Associated partial melting of crustal host rocks occurs around densely distributed dikes and sills. High silica rocks (e.g. granites) are generated by partial melting of the host rocks, melt segregation within dikes, and from fractional crystallization of basalts. Although the volume of these rocks is relatively small in our models compared to rocks with a mafic to intermediate composition, they provide important information about the processes of magma differentiation within arc continental crust.

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“…Table S1. Takahashi et al (2007) and Moghadam et al (2014). The stratigraphic column for the Chilas Complex ophiolite encompasses the ultramafic-mafic-anorthosite (UMA) association east of Chilas town in Pakistan.…”

Section: Tethyan Anorthosite-bearing Ophiolitesmentioning

confidence: 99%

“…Stratigraphic columns for the Neyriz and Chilas Complex Tethyan anorthosite‐bearing ophiolites (modified after Takahashi et al (2007) and Moghadam et al (2014). The stratigraphic column for the Chilas Complex ophiolite encompasses the ultramafic‐mafic‐anorthosite (UMA) association east of Chilas town in Pakistan.…”

Section: Geological Background and Data Presentationmentioning

confidence: 99%

Comparisons Between Tethyan Anorthosite‐Bearing Ophiolites and Archean Anorthosite‐Bearing Layered Intrusions: Implications for Archean Geodynamic Processes

Sotiriou

Polat

2020

Tectonics

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Elucidating the petrogenesis and geodynamic setting(s) of anorthosites in Archean layered intrusions and Tethyan ophiolites has significant implications for crustal evolution and growth throughout Earth history. Archean anorthosite‐bearing layered intrusions occur on every continent. Tethyan ophiolites occur in Europe, Africa, and Asia. In this contribution, the field, petrographic, petrological, and geochemical characteristics of 100 Tethyan anorthosite‐bearing ophiolites and 155 Archean anorthosite‐bearing layered intrusions are compared. Tethyan anorthosite‐bearing ophiolites range from Devonian to Paleocene in age are variably composite, contain anorthosites with highly calcic (An44–100) plagioclase and magmatic amphibole. These ophiolites formed predominantly at convergent plate margins, with some forming in mid‐ocean ridge, continental rift, and mantle plume settings. The predominantly convergent plate margin tectonic setting of Tethyan anorthosite‐bearing ophiolites is indicated by negative Nb and Ti anomalies and magmatic amphibole. Archean anorthosite‐bearing layered intrusions are Eoarchean to Neoarchean in age, have megacrystic anorthosites with highly calcic (An20–100) plagioclase and magmatic amphibole, and are interlayered with gabbros and leucogabbros and intrude pillow basalts. These Archean layered intrusions are interpreted to have predominantly formed at convergent plate margins, with the remainder forming in mantle plume, continental rift, oceanic plateau, postorogenic, anorogenic, mid‐ocean ridge, and passive continental margin settings. These layered intrusions predominantly crystallized from hydrous Ca‐ and Al‐rich tholeiitic magmas. The field, petrographic, and geochemical similarities between Archean and Tethyan anorthosites indicate that they were produced by similar geodynamic processes mainly in suprasubduction zone settings. We suggest that Archean anorthosite‐bearing layered intrusions and spatially associated greenstone belts represent dismembered subduction‐related Archean ophiolites.

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Geochemical modelling of the Chilas Complex in the Kohistan Terrane, northern Pakistan

Cited by 26 publications

References 22 publications

Geochemical Architecture of the Lower- to Middle-crustal Section of a Paleo-island Arc (Kohistan Complex, Jijal–Kamila Area, Northern Pakistan): Implications for the Evolution of an Oceanic Subduction Zone

Geochemical Architecture of the Lower- to Middle-crustal Section of a Paleo-island Arc (Kohistan Complex, Jijal–Kamila Area, Northern Pakistan): Implications for the Evolution of an Oceanic Subduction Zone

Insights into the Compositional Evolution of Crustal Magmatic Systems from Coupled Petrological-Geodynamical Models

Comparisons Between Tethyan Anorthosite‐Bearing Ophiolites and Archean Anorthosite‐Bearing Layered Intrusions: Implications for Archean Geodynamic Processes

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