Petrology and geochemistry of intrusive rocks from the South of Naqadeh, West Azerbaijan, Iran
| Autor | Abdollah Kordi - Afshin Ashja-Ardalan - Seyed-Jamal Sheikhzakariayi - Nasser Ashrafi |
| Cargo | Ph.D. Student in Petrology, Department of Geology, North Tehran Branch, Islamic Azad University, Tehran, Iran. - Assistant Professor, Department of Geology, North Tehran Branch, Islamic Azad University, Tehran, Iran. - Assistant Professor, Department of Geology, Science and Research Branch, Islamic Azad University, Tehran, Iran. - Assistant ... |
| Páginas | 524-558 |
Periódico do Núcleo de Estudos e Pesquisas sobre Gênero e Direito
Centro de Ciências Jurídicas - Universidade Federal da Paraíba
V. 8 - Nº 03 - Ano 2019
ISSN | 2179-7137 | http://periodicos.ufpb.br/ojs2/index.php/ged/index
524
PETROLOGY AND GEOCHEMISTRY OF INTRUSIVE ROCKS
FROM THE SOUTH OF NAQADEH, WEST AZERBAIJAN, IRAN
Abdollah Kordi
1
Afshin Ashja-Ardalan
2
Seyed-Jamal Sheikhzakariayi
3
Nasser Ashrafi
4
Abstract: The intrusive rocks of
Naqadeh are features of Laramide
magmatism in the Sanandaj–Sirjan zone.
According to petrographic studies, the
composition of intrusions consist of
acidic, intermediate, and basic rocks.
including syenogranites, monzogranite,
granodiorites, quartz diorites, quartz
monzonites, quartz monzonite, quartz
syenite, and olivine gabbro—in order of
abundance. Minerals forming intrusive
rocks include alkali feldspar (orthoclase
and microcline), quartz, plagioclase
(andesine to anorthite), amphibole
(magnesiohornblende to tschermakite
hornblende), pyroxene (diopside),
olivine (hyalosiderite to hortonlite),
apatite, titanite, zircon, muscovite, and
1
Ph.D. Student in Petrology, Department of Geology, North Tehran Branch, Islamic Azad
University, Tehran, Iran.
2
Assistant Professor, Department of Geology, North Tehran Branch, Islamic Azad University,
Tehran, Iran.
3
Assistant Professor, Department of Geology, Science and Research Branch, Islamic Azad
University, Tehran, Iran.
4
Assistant Professor, Department of Geology, Payame Noor University, Tehran, Iran.
Corresponding author: afshinashjaardalan@yahoo.com.
opaque minerals. The chemical analysis
of the granitoids revealed their
potassium-rich calc-alkaline nature,
falling within the meta-alumin to per-
alumin range in terms of alumin
saturation. Tectonomagmatic diagrams
for the studied rocks suggest that they are
compatible with granitoids of the
continental-subduction zone. Primitive-
mantle- and chondrite-normalized spider
diagrams indicated no depletion in any
elements, exhibiting a negative overall
slope which is consistent with
subduction patterns (negative Ta, Ti, Zr
anomalies, and positive K anomaly).
Overall, a review of field observations,
mineralogy, geochemistry, and diagrams
illustrating the sources of granites
Periódico do Núcleo de Estudos e Pesquisas sobre Gênero e Direito
Centro de Ciências Jurídicas - Universidade Federal da Paraíba
V. 8 - Nº 03 - Ano 2019
ISSN | 2179-7137 | http://periodicos.ufpb.br/ojs2/index.php/ged/index
525
showed that the intrusive rocks in the
study region are, in fact, I-type granite
and that the magmatism is a result of the
subduction of the oceanic crust,
Neotethys, under the Iranian continental
crust.
Keywords: Naqadeh Intrusive Rocks,
Sanandaj–Sirjan Zone, Petrography,
Minerals Chemistry, I-Type Granite.
1. Introduction
The study region stretches
northeast of Iran in West Azerbaijan
Province and is part of the northwestern
deformation and ophiolite belt of the
Sanandaj–Sirjan zone (Fig. 1) based on
the classification of structural units
(Stocklin, 1968) and structural–
sedimentary zones (Aghanabati, 2004)
of Iran. The zone (150–250 km wide and
1500 km long) features one of the most
complex structures in Iran (Alavi, 1994)
and houses the Zagros Mountains at its
center (Sengor, 1990). Even though the
age, nature, and source of these rock
masses remain unclear, they provide
essential information as regards the
geological history of the Sanandaj–
Sirjan zone. It is widely believed that the
rock masses are mainly of the calc-
alkaline granitoid type that formed
during the subduction of the Neotethys
under the Iranian plate (Sepahi Garw,
2007; Ahmadi Khalaji et al., 1999;
Ghalamghash et al., 2009; Yazdi et al.,
2017; Khodami and Kamali Shervedani
2018; Novruzov et al., 2019) and
following the collision of the Iranian and
Arabian Plates. A specific time scale is
yet to be presented for these events, but
there is a consensus that the subduction
process began during the Middle
Jurassic. However, the exact time of the
continental collision remains in dispute
with some authors dating it back to the
Late Cretaceous (Berberian and King,
2000; Mohajjel and Fergusson, 1981),
whereas others attribute it to the Eocene
(Numan, 2000; Ghasemi and Talbot,
2009; Mazhari et al., 2006) and even
Miocene (Mohajjel et al., 2003; Omrani
et al., 2008). Nonetheless, in the study
region, granitoid intrusive rocks from the
Late Cretaceous are abundant that
penetrated older formations (limestones
and Upper Cretaceous limestone
dolomites) during Laramide orogeny.
Contact metamorphism takes place at the
intersection between the rock mass and
country rocks resulting in the formation
of dolomite- and calcite-rich Hornfels.
As the final results of the granitic magma
Periódico do Núcleo de Estudos e Pesquisas sobre Gênero e Direito
Centro de Ciências Jurídicas - Universidade Federal da Paraíba
V. 8 - Nº 03 - Ano 2019
ISSN | 2179-7137 | http://periodicos.ufpb.br/ojs2/index.php/ged/index
526
sap, several white veins, reaching several
meters in thickness, penetrated various
parts of country rocks from Precambrian
to Cretaceous, as a sign of the last
magma injection phase in the region.
Given their intrusive nature, the enclaves
of the study region feature darker tones,
curved and round shapes with a
concentration of cognate enclaves
(autolith) southeast of the area.
Figure 1. Geology of Iran (Courtesy of Aghanabati, 2004). Structural–sedimentary zones
of Iran.
2. Geology
Stretching across 1200 km2, the
study region spans between the 45°15’
and 45°30’ E and 36°30’ and 37°00’ N
coordinates, 7 km south of Naqadeh, 30
km east of Piranshahr, and 39 km west of
Mahabad (Fig. 2). The oldest rock
outcrops in the region include a
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