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Unpublished MSc.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
Return to MS Theses completed in the Geological
Sciences Program, University at Albany