Peralkaline silicic melts of island arcs, active continental margins, and intraplate continental settings: Evidence from the investigation of melt inclusions in minerals and quenched glasses of rocks

Petrology ◽  
2009 ◽  
Vol 17 (4) ◽  
pp. 410-428 ◽  
Author(s):  
V. I. Kovalenko ◽  
V. B. Naumov ◽  
A. V. Girnis ◽  
V. A. Dorofeeva ◽  
V. V. Yarmolyuk
Keyword(s):  
Melt Inclusions ◽  
Continental Margins ◽  
Island Arcs ◽  
Active Continental Margins

Morphology of the continental margin

1978 ◽  
Vol 290 (1366) ◽  
pp. 75-85 ◽  
Keyword(s):  
Continental Margin ◽  
Turbidity Currents ◽  
Continental Margins ◽  
Island Arcs ◽  
Horizontal Shear ◽  
Passive Margins ◽  
Shelf Slope ◽  
Shear Motion ◽  
Continental Shelf Slope ◽  
Active Continental Margins

The continental margin is the surface morphological expression of the deeper fundamental transition between the thick low density continental igneous crust and the thin high density and chemically different oceanic igneous crust. Covering the transition are thick sediment accumulations comprising over half the total sediments of the ocean, so that the precise morphological boundaries often differ in position from those of the deeper geology. Continental margins are classified as active or passive depending on the level of seismicity. Active continental margins are divided into two categories, based on the depth distribution of earthquakes and the tectonic regime. Active transform margins, characterized by shear and shallow focus earthquakes, result from horizontal shear motion between plates. Active compressional margins are characterized by shallow, intermediate and deep earthquakes along a dipping zone, by oceanic trenches and by volcanic island arcs or mountain ranges depending on whether the margin is oceanocean or ocean-continent. Passive margins, found in the Atlantic and Indian Oceans, are formed initially by the rifting of continental crust and mark the ocean-continent boundary within the spreading plate. They are characterized by continental shelf, slope and rise physiographic provinces. Once clear of the rifting axis, they cool and subside. Sedimentation can prograde the shelf and load the edge leading to further down warping; changes of sea level lead to erosion by wave action and by ice; ocean currents and turbidity currents redistribute sediments; slumps occur in unstable areas. The passive and sediment-starved margin west of Europe is described where the following factors have been significant: (a) faulting related to initial rifting; (b) infilling and progradation by sediments; (c) slumping; (d) contour current erosion and deposition; (e)canyon erosion.

scholarly journals The final stage of the Acid Island Arc magmatism in the Northern Urals

2019 ◽  
Vol 489 (2) ◽  
pp. 166-169
Author(s):  
G. A. Petrov ◽  
N. I. Tristan ◽  
G. N. Borozdina ◽  
A. V. Maslov
Keyword(s):  
Volcanic Rocks ◽  
Southern Urals ◽  
Island Arc ◽  
Continental Margins ◽  
Island Arcs ◽  
Calc Alkaline ◽  
The Southern Urals ◽  
Northern Urals ◽  
Active Continental Margins ◽  
First Time

For the first time, the time of completion of the formation of calc-alkaline volcanic complexes of the Devonian Island Arc (Franian) in the Northern Urals was determined. It is shown that the late Devonian volcanic rocks of the Limka series have geochemical characteristics that bring them closer to the rocks of developed island arcs and active continental margins. The detected delay of the final episode of calc-alkaline volcanism in the Northern Urals in comparison with the similar event in the southern Urals may be due to the oblique nature of the subduction.

Subduction zones, island arcs and active continental margins

2010 ◽  
pp. 91-122
Author(s):  
Wolfgang Frisch ◽  
Martin Meschede ◽  
Ronald Blakey
Keyword(s):  
Subduction Zones ◽  
Continental Margins ◽  
Island Arcs ◽  
Active Continental Margins

scholarly journals Synrift sandstones and clayey rocks: bulk chemical composition and location on a number of discriminant paleogeodynamic diagrams

2019 ◽  
pp. 439-465
Author(s):  
A. V. Maslov ◽  
V. N. Podkovyrov ◽  
E. Z. Gareev ◽  
A. D. Nozhkin
Keyword(s):  
Chemical Composition ◽  
Continental Margins ◽  
Bulk Chemical Composition ◽  
East European ◽  
Fine Grained ◽  
Sedimentary Deposits ◽  
Data Points ◽  
Bulk Chemical ◽  
Clayey Rocks ◽  
Active Continental Margins

The bulk chemical composition of synrift sandstones and associated clayey rocks has been analized, and the distribution of the fields they form has been studied on discriminant paleogeodynamic SiO2K2O/Na2O [Roser, Korsch, 1986] and DF1DF2 [Verma, Armstrong-Altrin, 2013] diagrams. The studied sandstones in terms of bulk chemical composition mainly correspond to greywacke, lititic, arkose and subarkose psammites; Sublitites and quartz arenites are also found. A significant part in the analyzed data massif consists of psammites, in which log(Na2O/K2O)-1.0; missing on the Pettijohn classification chart. This confirms our conclusion, based on the results of mineralogical and petrographic studies, that the sedimentary infill of rift structures unites immature sandstones, the detrital framework of which was formed due to erosion of local sources, represented by various magmatic and sedimentary formations. Synrift clayey rocks, compared with sandstones, are composed of more mature fine-grained siliciclastics. As follows from the distribution of figurative data points of clayey rocks on the F1F2 diagram [Roser, Korsch, 1988], its sources were mainly sedimentary deposits. The content of most of the main rock-forming oxides in the synrift sandstones is almost the same as in silt-sandstone rocks present in the Upper Precambrian-Phanerozoic sedimentary mega-complex of the East European Plate, but at the same time differs significantly from the Proterozoic and Phanerozoic cratonic sediments, as well as from the average composition upper continental crust. It is shown that the distribution of the fields of syntift sandstones and clayey rocks on the SiO2K2O/Na2O diagram does not have any distinct features, and their figurative data points are localized in the areas of terrigenous rocks of passive and active continental margins. On the DF1DF2 diagram, the fields of the studied psammites and clayey rocks are located in areas of riftogenous and collisional environments. We have proposed a different position of the border between these areas in the diagram, which will require further verification.

Sign in / Sign up

Export Citation Format

Share Document