ABSTRACT
The Kula volcanics are a small Pleistocene to Recent volcanic
field located on the north shoulder of the Gediz graben,
approximately 120 km east of Izmir. The field consists of a
mixture of flows, small cones and pyroclastic deposits erupted
during three periods of volcanic activity beginning about one
million years ago. The volcanics range in composition from
basanites to trachybasalts, commonly porphyritic with abundant
clinopyroxene, olivine and amphibole phenocrysts. The lavas also
host a wide variety of megacrysts, crustal xenoliths and hydrous
mantle-derived nodules. These volcanics unconformably overlie
Neogene lacustrine sedimentary rocks and the metamorphic basement
rocks of the late Proterozoic-Eocene Menderes Massif.
Results of analyses of up to 24 lava samples and 4 hydrous
ultramafic nodules for whole rock major elements, selected trace
elements and Rb/Sr isotopes are presented. Paragenetic models
utilizing a least-squares subtraction program for major elements
suggests that fractional crystallization processes can explain
compositional variations between products erupted from the same
cone during a single eruptive period , but not between different
cones or different eruption periods. Trace element concentrations
do not seem to support the major element fractionation models,
which suggests a-more complex origin for the lavas. Variations in
trace element and Rb/Sr isotopic values support the hypothesis
that the Kula source region has undergone a recent enrichment in
incompatible elements, similar to recently proposed models of
paragenesis for ocean island basalts. This enrichment is thought
to be related to a change from a compressional to extensional
tectonic regime in western Turkey during Neogene time. Further
isotopic analyses will be necessary to adequately test this
hypothesis.
Dyer, J.M., 1987. Petrology of the Kula Volcanic Field, western
Turkey. Unpublished MSc. thesis, State University of New York at
Albany. 241 pp., +xii
University at Albany Science Library call number: SCIENCE
Oversize (*) QE 40 Z899 1987 D94
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