THE INDEX MINERALS AND MINERAL ASSEMBLAGES DETERMINED IN METAMORPHITES OF EVCİLER-ÇATKÖY (ÇAYIRALAN-YOZGAT) SEGMENT OF AKDAĞMADENİ MASSIF

Yıl 1999, Cilt: 121 Sayı: 121, 83 - 100, 01.02.1999

M. Bahadır Şahin Yavuz Erkan

Öz

In the studied area, which is
representing some part of metamorphic rocks of Akdağmadeni massif, some index
minerals and mineral assemblages reflecting progressive regional dynamo-thermal
metamorphism have been determined. In the metapelites belonging to the bottom
levels of metamorphic rocks, the index minerals such as biotite, garnet,
staurolite. kyanite. orthoclase and sillimanite and their assemblages have been
determined; in the semi-pelitic rocks which take place above the metapelitic
series we see index minerals such as plagioclase, calcite, diopsite,
hornblende, tremolite and their assemblages with the increasing carbonate in
environment. In the metacarbonates that we see widely at the top most of
metamorphic series, the mineral groups such as calcite, epidote, plagioclase,
diopsite and tremolite were found and they reflect metamorphism conditions. In
the mineral assemblages originated from various amphibolites found almost in
every lithology of metasedimentary sequence as intercalations and lenses, we
see hornblende, plagioclase and garnet as index minerals. Looking at the
experimental formation conditions of the mineral assemblages mentioned above,
we could say that the metamorphic rocks of the studied area were formed under
the progressive regional dynamo-thermal metamorphism conditions. It is pointed
out by looking at the index minerals and mineral assemblages in metapelitic
derivatives, metamorphism has occurred at 400-700 °C temperature and 3.5-6.5 kb
pressure conditions progressively. The mineral assemblages found in
semi-pelitic derivatives and metacarbonates also show a progressive
metamorphism of 350-600 °C and medium-high grade. The mineral assemblage we see
in the lithologies such as amphibolites reflects about 600 °C temperature and 6
kb pressure conditions.

Anahtar Kelimeler

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Kaynakça

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