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Unpublished MSc.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
thesis (scanned
text) - 26MB pdf file
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Geological
Sciences Program, University at Albany