TITLE:
Petrography, Temperature Measurement, and Economic Evaluation of Granitoid Pluton of Qohrud-Kashan Using EPMA, XRD, and XRF Analysis
AUTHORS:
Afshin Ashja Ardalan, Mina Khodadady, Mohammad Hashem Emami, Jamal Sheikh Zakariaie, Mohammad Hosein Razavi, Abdollah Yazdi
KEYWORDS:
Kashan, Qohrud, Granitoid, Temperature Measurement, Analysis
JOURNAL NAME:
Open Journal of Geology,
Vol.4 No.8,
August
28,
2014
ABSTRACT:
The area which is being
studied is located in northwest of Isfahan, 30 kilometers south of Kashan, and
southern section of Qmasar. The longitude of the area of study is
51°19'13"E to 51°26'26"E and its latitude is 33°34'24"N to 33°44'24"N.
Based on microscopic observations, modal analysis, and also based on their
location in the Streckeisen [QAPF], both the stones of the Qohrud batholitic
mass themselves and its enclaves are more in quartz monzonite ranges. Granitoid
also have quartz monzonite enclaves. These enclaves are from both microgranular
mafic and Autolith types which indicate the mixing of two magmas. At the center
of the pluton, there are indications of existence of main magma reservoir and
magma mixing. In terms of mineralogy, the granitoid rocks of the area very much
resemble I-type. The zoning of the plagioclases is both the normal kind and
variation invert and has andesine general composition. The probed biotite
sample contains iron and belongs to a granitic sample from the center of the
mass. Also, the ranking graph indicates biotite as the source of
recrystallization for the analyzed points. The probed biotite sample of the
Qohrud area showed formation temperature of 730 degrees centigrade. According
to the Rb and Sr contents, the source of the rocks is at depths of 20 to 30
kilometers from the earth’s surface that are depending on the subduction zone.
The formation temperature of the specimens of the Qohrud batholithic mass is
mostly between 900 to 1000 degrees centigrade. [At] the center of the mass
(around Qahrud), the amount of molybdenum is higher than the economic limit.