QE429 : Geology, petrology and geochemistry of the basalts of the Moghiseh area (SW-Sabzevar)
Thesis > Central Library of Shahrood University > Geosciences > MSc > 2014
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Abstarct: Moghise-Kalate sadat volcanic and volcano sedimentary rocks of cretacus,Oligo-Miocene , Pliocene and Quaternary sediment have been outcropped in South of Sabzevar ophiolitic belt and in the North margin of Central Iran zone.Moghise-Kalate sadat Oligocene volcanic rocks include a continuous series from basalt ,Olivine basalt and with related pyroclastic rocks associated . These rocks are results of eruption basaltic magma into low depth sedimentary basins of Oligocene . These lava are entered to Oligocene sedimentary basin by feeder dikes Oligocene detrital sedimentary rocks in Kalate sadat show a five of basaltic lavas , which already has been erupted as Quaternary basalts but new investigations indicate that they have been erupted in an Oligocene sedimentary basin.Oligocene volcano sedimentary rocks association has overlaid on the Eocene sediments and covered by Miocene and Pliocene sedimentary rocks. Olivine ,pyroxene and plagioclase are the main minerals and have porphyry ,Glomeroporphyry and microlitic –trachytic and Non-quilibrium texture (such as reaction rims and zoning) .The alkaline nature and intra-continental plate (back-arc) environment have been proved for these rocks baxsed on both magmatic series and tectonomagmatic diagram . Enrichment in LREE and depletion HREE are obviouse in chondrite and primitive mantle normalized spider diagrams. Spider diagrams of these rocks parallel trends of REE variation associated with the trends of major Oxides, compatible – incompatible elements variation diagram can be all indication of indicated a common unique source for these igneous rocks and confirm the role of the fractional crystallization in addition to assimilation and contamination with crustal rocks in the evolution of the magma . Neotethyan Oceanic lithospher subduction under the sothern margin of central Iran the Eocene , causes development of the extensional environments in a proto back arc basin magmatic subdution in Oligocene in Central Iran . the rocks studies plot in back-arc basin realm in petrogenetic and tectonomagmatic diagram .This setting has perfect concordance with the extentional regim prevailing in Central Iran back-arc basin during the Oligo-Miocene times . These rocks have been generated from about 5-10% partial melting of an enriched garnet lherzolitic mantle source in 100-110 Km depth.
Keywords:
#Oligocene #Back-arc #Volcanic rocks #Sabzevar #Basalt #Moghise Link
Keeping place: Central Library of Shahrood University
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Keeping place: Central Library of Shahrood University
Visitor: