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Mineralogical and petrographical characteristics
of the trachybasalt clasts from Upper Miocene-Lower Pliocene Detse
ignimbrites, Konya, Turkey.
Canbaş,
H. *,
Baş, H. **
*
Aksaray University, Aksaray-TURKEY, **Selcuk
University, Konya-TURKEY
hcanbas@aksaray.edu.tr
The
study are is situated of 40 km southwest of Konya (Central Anatolia), in
where extensive Neogene volcanics forms as lava domes, nue´e ardentes,
pyroclastic fall and flow ignimbrites deposits. The samples are
mostly andesite–dacite in composition; with some basalt, basaltic
andesite, basaltic trachyandesite, and trachyandesite. The tuff in the
area is represented by Bulumya, Detse, and Sadıklar ignimbrites. The
Detse ignimbrites contain however more clasts than the rest of the
ones. The composition of the clasts range from basaltic trachyandesite
and trachybasalts, with moderately alkaline affinity. The clasts form
as cornered to ellipsoidal shape with long axes ranging anywhere from a
few cm to 15 cm.
The Detse ignimbrite varies in composition from vitric to crystal
tuff. It contains predominantly quartz, biotite, plagioclase and
hornblende pheonocrysts, and minor opaque iron ore. Major constituents
are clinopyroxene, olivine, plagioclase and sanidine in a
holocrystalline porphyric texture. SEM-EDX analyses of the sanidine from
clasts of the trachybasalts show pronounced major element zoning
profiles. The sanidine has two feldspar phases exhibiting composite and
saw-tooth-type oscillations.
Keywords:
Trachybasalt, sanidine, SEM-EDX, Konya, Turkey |